#399

AGENTS.md

@@ -124,7 +124,7 @@ npm run preview
 - For arrays, never put whitespace or a line break immediately before `]`.
 - Keep the first element on the same line as `[` by default.
 - If an array would exceed the line limit, break after `[` and indent
-  elements by 4 spaces.
+  elements 4 spaces deeper than the statement's base indentation.
 
 ### Ruby delimiter and wrapping rules
 
@@ -140,6 +140,32 @@ npm run preview
   99 文字を超えるなら block 形式へ切り替へるか、message 定数化などで縮める。
 - Ruby の method chain や call argument を折り返す際、call-site の `)` を
   block close のやうに独立させない。
+- Ruby では、行末の `\` を用途を問はず一切使用しない。
+- Ruby では、文字列連結、logger message、method call、条件式、SQL 断片、
+  正規表現その他すべての式で、行末バックスラッシュによる継続を禁止する。
+- Ruby の block body は、その基準位置から 2 空白深くする。
+- Ruby の wrapped expression、method argument、array element、hash pair などの
+  continuation indentation は、その statement の基準位置から 4 空白深くする。
+- Ruby の continuation indentation を、行頭からの絶対空白数として扱はない。
+- Ruby では、暗黙的に継続可能な構文を優先し、method call、array、Hash 及び
+  括弧内ではバックスラッシュなしで改行する。
+- Ruby では、行長制限を守るために行末バックスラッシュを導入してはならない。
+- Ruby で行末バックスラッシュが必要に見える場合は、括弧内で自然に改行する、
+  一つの文字列補間へまとめる、中間変数へ分ける、`format` を使ふ、heredoc を
+  使ふ、array 又は Hash を組み立ててから処理する、条件式全体を括弧で囲む、
+  method へ抽出する、のいづれかへ書き換へる。
+- Ruby では、一つの文字列を、改行をまたいだ隣接文字列 literal として記述しない。
+- Ruby では、method argument 内でも、複数の文字列 literal を区切りなしで縦に
+  並べない。
+- RSpec の `describe`、`context`、`it` 等の description が長い場合は、意味を
+  保ったまま一行へ収まる文言へ短縮する。
+- 文字列を短縮できない場合は、用途に応じて `format`、heredoc 又は中間変数を
+  検討する。
+- ただし RSpec description では、原則として簡潔な一行の文字列を使ふ。
+- formatter 又は自動修正にも、Ruby の行末バックスラッシュを生成させない。
+- 新規 code だけでなく、今回触れる Ruby code にも行末バックスラッシュを残さない。
+- 例へば class body 内の array は、class body の 2 空白を基準に、更に 4 空白
+  深くするため、結果として行頭から 6 空白になる。
 
 Bad:
 
@@ -191,6 +217,63 @@ end
 
 Bad:
 
+```rb
+Rails.logger.info(
+    "post_import_metadata_fetch_failure "\
+    "#{ payload.to_json }")
+```
+
+Good:
+
+```rb
+payload = {
+    error: e.class.name,
+    message: e.message }
+
+Rails.logger.info(
+    "post_import_metadata_fetch_failure #{ payload.to_json }")
+```
+
+Bad:
+
+```rb
+message = "first "\
+          "second"
+```
+
+Good:
+
+```rb
+message = format(
+    '%<first>s %<second>s',
+    first: 'first',
+    second: 'second')
+```
+
+Bad:
+
+```rb
+result = first_value + \
+         second_value
+```
+
+Bad:
+
+```rb
+it(
+    'returns 409 when stale changes '
+    'do not conflict'
+) do
+```
+
+Good:
+
+```rb
+it 'returns mergeable 409 for stale non-conflicting changes' do
+```
+
+Bad:
+
 ```rb
 records.each {
   do_work(_1) }
@@ -225,20 +308,37 @@ records.each {
   formatting as the local reference shape: component and callback bodies use
   2-space block indentation, single-line bodies do not gain unnecessary
   braces, wrapped expressions use 4-space continuation indentation, multi-
-  stage ternaries use explicit parentheses, and only complete leading runs
-  of 8 spaces are compressed to tabs.
-- In TypeScript and TSX only, tabs are for leading 8-column compression only.
+  stage ternaries use explicit parentheses, and TypeScript / TSX indentation
+  and alignment whitespace compress every complete run of 8 spaces to tabs.
 - A tab does not represent one indentation level.
-- Do not replace 2-space or 4-space indentation with tabs.
-- First determine visible indentation using 2-space block indentation and
-  4-space continuation indentation, then compress only complete leading runs
-  of 8 spaces into tabs.
-- Tabs are only for leading indentation, never for spaces after non-space
-  text.
-- Keep residual leading 2, 4, or 6 spaces after any tab compression.
+- In TypeScript and TSX, first determine visible indentation using 2-space
+  block indentation and 4-space continuation indentation, then compress every
+  complete run of 8 spaces used for indentation or column alignment to tabs.
+- In TypeScript and TSX, 8-space compression is mandatory, not optional.
+- In TypeScript and TSX, this applies both to leading indentation and to
+  alignment whitespace after non-space text, such as aligned inline type
+  columns.
+- In TypeScript and TSX, keep residual 2, 4, or 6 spaces after each tab
+  compression.
+- In TypeScript and TSX, do not treat a tab as one logical indentation level.
+- In TypeScript and TSX, do not alter string literals, template-literal
+  contents, regular expressions, or user-facing text merely to apply tab
+  compression.
 - Examples: 2 columns = 2 spaces, 4 columns = 4 spaces, 6 columns = 6
   spaces, 8 columns = 1 tab, 10 columns = 1 tab + 2 spaces, 12 columns = 1
-  tab + 4 spaces, 16 columns = 2 tabs.
+  tab + 4 spaces, 14 columns = 1 tab + 6 spaces, 16 columns = 2 tabs.
+- When TypeScript or TSX code already uses column alignment, apply the same
+  8-space compression rule to that alignment whitespace.
+- Example:
+
+```ts
+type Props = {
+    row:	      PostImportRow
+    displayNumber?:   number
+    onEdit?:	  () => void
+    onRetry?:	  () => void
+    onToggleSkip?:    (checked: boolean) => void }
+```
 - TypeScript and TSX imports may stay on one line if they remain within the
   line limit; do not expand short type-only imports mechanically.
 - Keep runtime value imports and type imports in separate declarations.
@@ -285,6 +385,13 @@ case 'no':
   Ruby-style numbered parameter names. Reserve numbered parameters for Ruby.
   Use a meaningful callback parameter name such as `row`, `item`, `value`,
   `entry`, or `result`.
+- In JavaScript, JSX, TypeScript, and TSX, use `cn` from `@/lib/utils`
+  whenever `className` combines multiple values, conditional classes, or a
+  caller-provided `className` prop.
+- Do not construct `className` with template literals, `${ ... }`, string
+  concatenation, arrays joined with spaces, or feature-local class-merging
+  helpers.
+- A static `className="..."` containing only fixed classes does not need `cn`.
 - If code appears to need a distinction between `null` and `undefined`, treat
   that as a design smell and revise the logic to avoid the distinction.
   External library APIs that explicitly require distinguishing the two are the
@@ -460,9 +567,39 @@ and layout reuse, follow `frontend/AGENTS.md`.
   structure, control flow, or variable mutability unless the requested style
   explicitly requires it.
 - Do not add production dependencies without explicit approval.
+- Do not add user-facing copy, helper text, descriptions, notes, tooltips,
+  placeholders, empty-state messages, loading messages, or explanatory text
+  unless the user explicitly specified the wording.
+- When new user-facing wording appears necessary, ask the user for the exact
+  wording and placement before implementing it.
+- Do not invent replacement copy when removing unrequested wording.
 - Do not create, modify, or run tests unless the user explicitly asks for
-  test work. When the user asks for tests, keep working and rerun them until
-  they pass or the remaining failure is clearly blocked.
+  test work. When the user asks for tests, keep working within the permitted
+  test-file scope and rerun them until they pass or the remaining failure is
+  clearly blocked.
+- Test-only work includes adding, updating, deleting, reorganising, or fixing
+  SyntaxError in tests. During test-only work, do not modify production code.
+- During test-only work, do not change production constants, behaviour, API
+  contracts, validation, routes, authentication, permissions, UI, copy,
+  dependencies, limits, thresholds, defaults, migrations, schema, or
+  environment settings to satisfy tests.
+- Do not make production code match failing tests, mock assumptions, fixtures,
+  snapshots, old expectations, or stale setup. This includes changing
+  production constants merely because a test expects a different value.
+- If test work reveals a production bug, spec mismatch, or missing behaviour,
+  stop without modifying production code and report: the failing test or
+  discovered issue, the related production file, the actual behaviour, the
+  expected behaviour, and why a production change appears necessary.
+- Modify production code for test failures only when the user explicitly asks
+  for that production change. Do not expand a test task into a production task
+  on your own authority.
+- If the user explicitly asks for both production implementation and test
+  updates, implement production code to the confirmed specification first,
+  then add or update tests to verify that specification. Never roll production
+  behaviour back to satisfy old tests.
+- If it is unclear whether the test or the production implementation is stale,
+  or a test cannot be corrected without changing production code, ask the user
+  instead of guessing.
 
 ## Backend rules
 
@@ -516,6 +653,11 @@ and layout reuse, follow `frontend/AGENTS.md`.
 - Mobile UI must be checked as a first-class layout. Avoid wide fixed content,
   make dense controls wrap or scroll intentionally, and keep tag/filter
   controls usable without horizontal page overflow.
+- Frontend のスマホ／PC表示境界は原則 `md` とする。
+- button stack、footer action、dialogue action は `md` 未満で縦並び、
+  `md` 以上で横並びとする。
+- 同じ画面内で `sm` と `md` を混在させて中間 layout を作らない。
+- 明確に別の responsive 要件がある component だけを例外とする。
 - For mobile horizontal scrollers, make the scroll direction and item sizing
   explicit, and ensure chip text remains readable in both light and dark modes.
 - In TypeScript and TSX, prefer direct comparison operators such as `===` and
@@ -580,10 +722,10 @@ and layout reuse, follow `frontend/AGENTS.md`.
   beginning of a line.
 - The TSX-specific self-review must confirm JSX closing markers and closing
   parentheses keep the surrounding compact style.
-- The TypeScript/TSX self-review must confirm leading block indentation uses
-  2 spaces per level, wrapped continuations use the repository's 4-space
-  continuation alignment, and complete leading runs of 8 spaces may be
-  compressed to tabs.
+- The TypeScript/TSX self-review must confirm block indentation uses 2 spaces
+  per level, wrapped continuations use the repository's 4-space continuation
+  alignment, and every complete run of 8 spaces used for indentation or
+  alignment has been compressed to tabs.
 - Prefer `const` arrow functions for TypeScript/TSX component and helper declarations.
 - Put two blank lines before and after top-level `const` function
   declarations, unless imports, exports, or file boundaries make that awkward.
@@ -596,9 +738,18 @@ and layout reuse, follow `frontend/AGENTS.md`.
 - Indent the block body 2 spaces deeper than the keyword and opening brace.
 - Put the closing `}` on its own line at the same indentation as the keyword.
 - Do not write `try {`, `catch {`, or `finally {`.
-- In TypeScript and TSX, convert every complete leading run of 8 spaces to a
-  tab character.
-- A leading tab is exactly equivalent to 8 leading spaces.
+- In TypeScript and TSX, convert every complete run of 8 spaces used for
+  indentation or alignment to a tab character.
+- In TypeScript and TSX, a tab is exactly equivalent to 8 columns, whether it
+  appears at the beginning of a line or in alignment whitespace after
+  non-space text.
+- In TSX, JSX nesting uses 2-space block indentation and wrapped JSX
+  attributes use 4-space continuation indentation; after visible columns are
+  determined, compress every complete run of 8 spaces in the resulting
+  indentation or alignment to tabs.
+- In TSX, do not leave JSX subtree indentation at 8, 10, 12, 14, or 16
+  columns as spaces alone; convert each complete run of 8 spaces to tabs and
+  keep only the residual 2, 4, or 6 spaces.
 - In TypeScript and TSX function declarations, including `const` arrow
   function declarations, classify the parameter list before placing the closing
   `)`.
@@ -1241,9 +1392,9 @@ to `.ts` and `.tsx`:
 7. JSX `>` and `/>` stay with the final prop unless nearby code proves
    otherwise.
 8. JSX closing parentheses keep the compact local style.
-9. Leading block indentation uses 2 spaces per level, wrapped continuations
-   use the repository's 4-space continuation alignment, and complete leading
-   runs of 8 spaces may be compressed to tabs.
+9. Block indentation uses 2 spaces per level, wrapped continuations use the
+   repository's 4-space continuation alignment, and every complete run of 8
+   spaces used for indentation or alignment has been compressed to tabs.
 10. No line has trailing whitespace.
 
 Preferred:

backend/app/controllers/post_imports_controller.rb

@@ -1,44 +0,0 @@
-class PostImportsController < ApplicationController
-  before_action :require_member!
-
-  def preview
-    rows = PostImportPreviewer.new.preview_rows(
-        rows: PostImportUrlListParser.parse(params[:source]))
-    render json: { rows: }
-  rescue ArgumentError => e
-    render_bad_request e.message
-  end
-
-  def validate
-    rows = normalised_import_rows allow_warning_fields: true
-    changed_row = Integer(params[:changed_row], exception: false)
-    result =
-        PostImportPreviewer.new.preview_rows(rows:,
-                                             fetch_metadata: changed_row,
-                                             metadata_cache: { })
-    render json: { rows: result }
-  rescue ArgumentError => e
-    render_bad_request e.message
-  end
-
-  def create
-    result = PostImportRunner.new(actor: current_user,
-                                  rows: normalised_import_rows).run
-    render json: result, status: result[:created].positive? ? :created : :ok
-  rescue ArgumentError => e
-    render_bad_request e.message
-  end
-
-  private
-
-  def require_member!
-    return head :unauthorized unless current_user
-    return if current_user.gte_member?
-
-    head :forbidden
-  end
-
-  def normalised_import_rows allow_warning_fields: false
-    PostImportRowNormaliser.normalise!(params[:rows], allow_warning_fields:)
-  end
-end

backend/app/controllers/posts_controller.rb

@@ -1,5 +1,6 @@
 class PostsController < ApplicationController
   Event = Struct.new(:post, :tag, :user, :change_type, :timestamp, keyword_init: true)
+  MAX_BULK_REQUEST_BYTES = 40 * 1024 * 1024
 
   class VideoMsParseError < ArgumentError
     ;
@@ -114,6 +115,77 @@ class PostsController < ApplicationController
     render json: PostRepr.base(post, current_user)
   end
 
+  def metadata
+    return head :unauthorized unless current_user
+    return head :forbidden unless current_user.gte_member?
+    return render_bad_request('URL は必須です．') if params[:url].blank?
+
+    normal_url = PostUrlNormaliser.normalise(params[:url].to_s)
+    return render_validation_error(fields: { url: ['URL が不正です．'] }) if normal_url.blank?
+
+    Preview::UrlSafety.validate(normal_url)
+    existing_post = Post.with_attached_thumbnail.find_by(url: normal_url)
+    if existing_post.present?
+      return render json: {
+          url: normal_url,
+          title: nil,
+          thumbnail_base: nil,
+          tags: nil,
+          display_tags: [],
+          original_created_from: nil,
+          original_created_before: nil,
+          duration: nil,
+          video_ms: nil,
+          field_warnings: { },
+          base_warnings: [],
+          existing_post_id: existing_post.id,
+          existing_post: compact_post(existing_post.id) }
+    end
+
+    metadata = PostMetadataFetcher.fetch(normal_url)
+    field_warnings = { }
+    field_warnings[:title] = ['タイトルを取得できませんでした．'] if metadata[:title].blank?
+    if metadata[:thumbnail_base].blank?
+      field_warnings[:thumbnail_base] = ['サムネールを取得できませんでした．']
+    end
+
+    render json: {
+        url: normal_url,
+        title: metadata[:title],
+        thumbnail_base: metadata[:thumbnail_base],
+        tags: metadata[:tags],
+        display_tags: metadata[:display_tags],
+        original_created_from: metadata[:original_created_from],
+        original_created_before: metadata[:original_created_before],
+        duration: metadata[:duration],
+        video_ms: metadata[:video_ms],
+        field_warnings: field_warnings,
+        base_warnings: [],
+        existing_post_id: nil,
+        existing_post: nil }
+  rescue ArgumentError => e
+    render_bad_request e.message
+  rescue Preview::UrlSafety::UnsafeUrl => e
+    render_validation_error fields: { url: [e.message] }
+  rescue Preview::HttpFetcher::FetchFailed,
+         Preview::HttpFetcher::FetchTimeout,
+         Preview::HttpFetcher::ResponseTooLarge
+    render json: {
+        url: normal_url,
+        title: nil,
+        thumbnail_base: nil,
+        tags: nil,
+        display_tags: [],
+        original_created_from: nil,
+        original_created_before: nil,
+        duration: nil,
+        video_ms: nil,
+        field_warnings: { url: ['自動取得に失敗しました．'] },
+        base_warnings: [],
+        existing_post_id: nil,
+        existing_post: nil }
+  end
+
   def show
     post =
         Post
@@ -142,17 +214,41 @@ class PostsController < ApplicationController
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
+    preflight = PostCreatePreflight.new(
+        attributes: post_create_attributes,
+        thumbnail: params[:thumbnail],
+        host: request.base_url).run
+    return render json: dry_run_json(preflight) if bool?(:dry)
+    if preflight[:existing_post_id].present?
+      post = Post.new(url: preflight[:url])
+      post.errors.add :url, :taken
+      return render_post_form_record_invalid post
+    end
+
     post = PostCreator.new(actor: current_user,
-                           attributes: { title: params[:title], url: params[:url],
-                                         thumbnail: params[:thumbnail], tags: params[:tags],
-                                         original_created_from: params[:original_created_from],
-                                         original_created_before: params[:original_created_before],
-                                         parent_post_ids: parse_parent_post_ids,
-                                         video_ms: params[:video_ms],
-                                         duration: params[:duration] }).create!
+                           attributes: post_create_attributes.merge(
+                               preflight.slice(
+                                   :url,
+                                   :title,
+                                   :thumbnail_base,
+                                   :tags,
+                                   :parent_post_ids,
+                                   :original_created_from,
+                                   :original_created_before,
+                                   :duration,
+                                   :video_ms,
+                                   :direct_tag_specs,
+                                   :default_tag_specs,
+                                   :snapshot_tag_specs,
+                                   :post_tag_specs,
+                                   :tag_sections,
+                                   :normalised_parent_post_ids).symbolize_keys).merge(
+                               thumbnail: params[:thumbnail])).create!
 
     post.reload
     render json: PostRepr.base(post), status: :created
+  rescue PostCreatePreflight::ValidationFailed => e
+    render_validation_error fields: e.fields, base: e.base_errors
   rescue Tag::NicoTagNormalisationError
     render_validation_error fields: { tags: 'ニコニコ・タグは直接指定できません．' }
   rescue Tag::DeprecatedTagNormalisationError
@@ -161,6 +257,8 @@ class PostsController < ApplicationController
     render_validation_error fields: { tags: ['タグ区間の記法が不正です．'] }
   rescue PostCreator::VideoMsParseError
     render_validation_error fields: { video_ms: ['動画時間の記法が不正です．'] }
+  rescue Post::RemoteThumbnailFetchFailed
+    render_validation_error fields: { thumbnail_base: ['サムネイル画像の取得に失敗しました．'] }
   rescue MiniMagick::Error
     render_validation_error fields: { thumbnail: ['サムネイル画像の変換に失敗しました．'] }
   rescue ArgumentError => e
@@ -169,6 +267,25 @@ class PostsController < ApplicationController
     render_post_form_record_invalid e.record
   end
 
+  def bulk
+    return head :unauthorized unless current_user
+    return head :forbidden unless current_user.gte_member?
+    return head :unsupported_media_type unless request.content_mime_type == Mime[:multipart_form]
+    return head :payload_too_large if request.content_length.to_i > MAX_BULK_REQUEST_BYTES
+    posts = parse_bulk_posts_manifest
+    thumbnails = parse_bulk_thumbnails(posts.length)
+    result = PostBulkCreator.new(
+        actor: current_user,
+        posts:,
+        thumbnails:,
+        host: request.base_url).run
+    render json: result
+  rescue JSON::ParserError
+    render_bad_request 'posts manifest の JSON が不正です．'
+  rescue ArgumentError => e
+    render_validation_error base: [e.message]
+  end
+
   def viewed
     return head :unauthorized unless current_user
 
@@ -463,6 +580,79 @@ class PostsController < ApplicationController
     }.uniq
   end
 
+  def post_create_attributes
+    { title: params[:title],
+      url: params[:url],
+      thumbnail_base: params[:thumbnail_base],
+      tags: params[:tags],
+      original_created_from: params[:original_created_from],
+      original_created_before: params[:original_created_before],
+      parent_post_ids: parse_parent_post_ids,
+      video_ms: params[:video_ms],
+      duration: params[:duration] }
+  end
+
+  def parse_bulk_posts_manifest
+    manifest = params[:posts]
+    raise ArgumentError, 'posts は必須です．' if manifest.blank?
+    raise ArgumentError, 'posts は JSON 文字列で指定してください．' unless manifest.is_a?(String)
+
+    posts = JSON.parse(manifest)
+    raise ArgumentError, 'posts は配列で指定してください．' unless posts.is_a?(Array)
+    raise ArgumentError, '投稿件数は 1 件以上必要です．' if posts.empty?
+    raise ArgumentError, '投稿件数が多すぎます．' if posts.length > 100
+    raise ArgumentError, 'posts 要素の形式が不正です．' unless posts.all? { _1.is_a?(Hash) }
+
+    posts
+  end
+
+  def parse_bulk_thumbnails post_count
+    thumbnails = { }
+    raw = params[:thumbnails]
+    return thumbnails if raw.blank?
+    raise ArgumentError, 'thumbnail key が不正です．' unless raw.respond_to?(:to_unsafe_h)
+
+    raw.to_unsafe_h.each do |key, value|
+      raise ArgumentError, 'thumbnail key が不正です．' unless key.to_s.match?(/\A\d+\z/)
+
+      index = Integer(key, 10)
+      raise ArgumentError, 'thumbnail index が範囲外です．' if index.negative? || index >= post_count
+      raise ArgumentError, 'thumbnail index が重複しています．' if thumbnails.key?(index)
+      unless value.is_a?(ActionDispatch::Http::UploadedFile)
+        raise ArgumentError, 'thumbnail upload が不正です．'
+      end
+
+      thumbnails[index] = value
+    end
+
+    thumbnails
+  end
+
+  def compact_post post_id
+    return nil if post_id.blank?
+
+    post = Post.with_attached_thumbnail.find_by(id: post_id)
+    PostCompactRepr.base(post, host: request.base_url)
+  end
+
+  def dry_run_json preflight
+    preflight.slice(
+        :url,
+        :title,
+        :thumbnail_base,
+        :tags,
+        :display_tags,
+        :parent_post_ids,
+        :original_created_from,
+        :original_created_before,
+        :duration,
+        :video_ms,
+        :field_warnings,
+        :base_warnings,
+        :existing_post_id,
+        :existing_post)
+  end
+
   def sync_parent_posts! post, parent_post_ids
     if parent_post_ids.include?(post.id)
       post.errors.add :parent_post_ids, '自分自身を親投稿にはできません．'
@@ -542,6 +732,7 @@ class PostsController < ApplicationController
 
   def post_incoming_snapshot title:, original_created_from:, original_created_before:,
                              tag_names:, video_ms_param:, duration_param:, parent_post_ids:
+    validate_original_created_values!(original_created_from, original_created_before)
     Tag.normalise_tags!(tag_names, with_tagme: false, deny_deprecated: true,
                                         with_sections: true) =>
         { tags:, sections: }
@@ -579,6 +770,23 @@ class PostsController < ApplicationController
     value.to_s
   end
 
+  def validate_original_created_values! original_created_from, original_created_before
+    candidate = Post.new(
+        url: 'https://example.invalid/original-created-validation',
+        original_created_from:,
+        original_created_before:)
+    candidate.valid?
+    fields = [:original_created_from, :original_created_before, :original_created_at]
+    relevant_errors = candidate.errors.select { fields.include?(_1.attribute) }
+    return if relevant_errors.empty?
+
+    invalid_post = Post.new
+    relevant_errors.each { |error|
+      invalid_post.errors.add(error.attribute, error.message)
+    }
+    raise ActiveRecord::RecordInvalid, invalid_post
+  end
+
   def section_literal section
     "[#{ Post.ms_to_time(section[0]) }-#{ section[1] ? Post.ms_to_time(section[1]) : '' }]"
   end

backend/app/controllers/preview_controller.rb

@@ -18,14 +18,12 @@ class PreviewController < ApplicationController
   def thumbnail
     return render_bad_request('URL は必須です．') if params[:url].blank?
 
-    image = MiniMagick::Image.read(Preview::ThumbnailFetcher.fetch(params[:url]))
-    image.auto_orient
-    image.resize '180x180>'
-    image.format 'png'
-    width, height = image.dimensions
-    raise Preview::ThumbnailFetcher::GenerationFailed, 'サムネール画像の変換に失敗しました．' if width > 180 || height > 180
-
-    send_data image.to_blob, type: 'image/png', disposition: 'inline'
+    attachment =
+        Post.resized_thumbnail_attachment(
+            StringIO.new(Preview::ThumbnailFetcher.fetch(params[:url])))
+    send_data attachment[:io].read,
+              type: attachment[:content_type],
+              disposition: 'inline'
   rescue Preview::UrlSafety::UnsafeUrl => e
     render_bad_request(e.message)
   rescue Preview::HttpFetcher::FetchTimeout => e

backend/app/models/post.rb

@@ -1,7 +1,9 @@
 class Post < ApplicationRecord
   require 'date'
   require 'mini_magick'
+  require 'nokogiri'
   require 'stringio'
+  require 'timeout'
 
   class RemoteThumbnailFetchFailed < StandardError; end
 
@@ -11,22 +13,45 @@ class Post < ApplicationRecord
   ORIGINAL_CREATED_ORDER_MESSAGE = 'オリジナルの作成日時の順番がをかしぃです．'.freeze
   ORIGINAL_CREATED_MINIMUM_RANGE_MESSAGE =
       'オリジナルの作成日時の範囲は1分以上必要です．'.freeze
-
-  def self.resized_thumbnail_attachment(upload)
+  REMOTE_SVG_CONTENT_TYPE = 'image/svg+xml'.freeze
+  MAX_SVG_DIMENSION = 4_096
+  MAX_SVG_PIXELS = 16_777_216
+  THUMBNAIL_PROCESS_TIMEOUT = 5.seconds
+  def self.resized_thumbnail_attachment(upload, content_type: nil)
     upload.rewind
-    image = MiniMagick::Image.read(upload.read)
-    image.resize '180x180^'
-    image.gravity 'Center'
-    image.extent '180x180'
-    image.format 'jpg'
+    bytes = upload.read
+    blob = Timeout.timeout(THUMBNAIL_PROCESS_TIMEOUT) do
+      image = image_for_thumbnail_upload(bytes, content_type:)
+      image.auto_orient
+      image.resize '180x180'
+      image.format 'jpg'
+      image.to_blob
+    end
 
-    { io: StringIO.new(image.to_blob),
+    { io: StringIO.new(blob),
       filename: 'resized_thumbnail.jpg',
       content_type: 'image/jpeg' }
+  rescue Timeout::Error
+    raise MiniMagick::Error, 'サムネイル画像の変換に失敗しました．'
   ensure
     upload.rewind
   end
 
+  def self.remote_thumbnail_attachment(raw_url)
+    response = Preview::ThumbnailFetcher.fetch_image_response(raw_url)
+    resized_thumbnail_attachment(
+        StringIO.new(response.body),
+        content_type: response.content_type)
+  rescue Preview::UrlSafety::UnsafeUrl,
+         Preview::ThumbnailFetcher::GenerationFailed,
+         Preview::HttpFetcher::FetchFailed,
+         Preview::HttpFetcher::FetchTimeout,
+         Preview::HttpFetcher::ResponseTooLarge,
+         Timeout::Error,
+         MiniMagick::Error => e
+    raise RemoteThumbnailFetchFailed, e.message
+  end
+
   belongs_to :uploaded_user, class_name: 'User', optional: true
 
   has_many :post_tags, dependent: :destroy, inverse_of: :post
@@ -113,7 +138,10 @@ class Post < ApplicationRecord
   end
 
   def self.section_literal section
-    "[#{ Post.ms_to_time(section.begin_ms) }-#{ section.end_ms ? Post.ms_to_time(section.end_ms) : '' }]"
+    end_ms =
+        section.end_ms ? Post.ms_to_time(section.end_ms) : ''
+
+    "[#{ Post.ms_to_time(section.begin_ms) }-#{ end_ms }]"
   end
 
   def self.ms_to_time ms
@@ -157,17 +185,7 @@ class Post < ApplicationRecord
   end
 
   def attach_thumbnail_from_url! raw_url
-    response = Preview::ThumbnailFetcher.fetch_image_response(raw_url)
-    thumbnail.attach(
-        self.class.resized_thumbnail_attachment(
-            StringIO.new(response.body)))
-  rescue Preview::UrlSafety::UnsafeUrl,
-         Preview::ThumbnailFetcher::GenerationFailed,
-         Preview::HttpFetcher::FetchFailed,
-         Preview::HttpFetcher::FetchTimeout,
-         Preview::HttpFetcher::ResponseTooLarge,
-         MiniMagick::Error => e
-    raise RemoteThumbnailFetchFailed, e.message
+    thumbnail.attach(self.class.remote_thumbnail_attachment(raw_url))
   end
 
   private
@@ -209,6 +227,179 @@ class Post < ApplicationRecord
     self.url = PostUrlNormaliser.normalise(url) || url.strip
   end
 
+  def self.image_for_thumbnail_upload(bytes, content_type: nil)
+    if svg_content_type?(content_type) || svg_document_bytes?(bytes)
+      return decode_svg_thumbnail(bytes)
+    end
+
+    raise MiniMagick::Error, 'サムネイル画像の形式が不正です．' unless raster_thumbnail_bytes?(bytes)
+
+    decode_raster_thumbnail(bytes)
+  end
+
+  def self.raster_thumbnail_bytes?(bytes)
+    raster_thumbnail_format(bytes).present?
+  end
+
+  def self.remote_thumbnail_image_bytes?(bytes, content_type: nil)
+    return true if svg_content_type?(content_type) || svg_document_bytes?(bytes)
+
+    raster_thumbnail_bytes?(bytes)
+  end
+
+  def self.svg_content_type?(content_type)
+    content_type.to_s.split(';', 2).first.to_s.downcase.strip == REMOTE_SVG_CONTENT_TYPE
+  end
+
+  def self.svg_document_bytes?(bytes)
+    document = Nokogiri::XML(
+        bytes,
+        nil,
+        nil,
+        Nokogiri::XML::ParseOptions::STRICT |
+        Nokogiri::XML::ParseOptions::NONET)
+    document.root&.name == 'svg'
+  rescue Nokogiri::XML::SyntaxError
+    false
+  end
+
+  def self.decode_raster_thumbnail(bytes)
+    MiniMagick::Image.read(bytes)
+  end
+
+  def self.decode_svg_thumbnail(bytes)
+    MiniMagick::Image.read(sanitised_svg_bytes(bytes))
+  end
+
+  def self.raster_thumbnail_format(bytes)
+    binary = bytes.to_s.b
+    return 'jpeg' if binary.start_with?("\xFF\xD8\xFF".b)
+    return 'png' if binary.start_with?("\x89PNG\r\n\x1A\n".b)
+    return 'gif' if binary.start_with?('GIF87a'.b) || binary.start_with?('GIF89a'.b)
+    return 'webp' if binary.bytesize >= 12 &&
+                     binary.start_with?('RIFF'.b) &&
+                     binary.byteslice(8, 4) == 'WEBP'
+
+    nil
+  end
+
+  def self.sanitised_svg_bytes(bytes)
+    parse_options =
+        Nokogiri::XML::ParseOptions::STRICT |
+        Nokogiri::XML::ParseOptions::NONET
+    document = Nokogiri::XML(
+        bytes,
+        nil,
+        nil,
+        parse_options)
+    root = document.root
+    raise MiniMagick::Error, 'SVG が不正です．' if root == nil || root.name != 'svg'
+    raise MiniMagick::Error, 'SVG が不正です．' if document.internal_subset != nil
+    raise MiniMagick::Error, 'SVG が不正です．' if svg_uses_disallowed_features?(document)
+
+    width, height = svg_dimensions(root)
+    raise MiniMagick::Error, 'SVG が大きすぎます．' if width == nil || height == nil
+    if width > MAX_SVG_DIMENSION || height > MAX_SVG_DIMENSION || width * height > MAX_SVG_PIXELS
+      raise MiniMagick::Error, 'SVG が大きすぎます．'
+    end
+
+    document.to_xml
+  rescue Nokogiri::XML::SyntaxError
+    raise MiniMagick::Error, 'SVG が不正です．'
+  end
+
+  def self.svg_uses_disallowed_features?(document)
+    document.traverse.any? do |node|
+      next false unless node.element?
+
+      name = node.name.to_s.downcase
+      next true if name == 'script' || name == 'foreignobject'
+      next style_contains_disallowed_urls?(node.text.to_s) if name == 'style'
+
+      node.attribute_nodes.any? do |attribute|
+        attribute_name = attribute.name.to_s.downcase
+        attribute_value = attribute.value.to_s
+        attribute_name.start_with?('on') ||
+            external_svg_reference?(attribute_name, attribute_value)
+      end
+    end
+  end
+
+  def self.external_svg_reference?(attribute_name, attribute_value)
+    if ['href', 'xlink:href', 'src'].include?(attribute_name)
+      return external_svg_url?(attribute_value)
+    end
+    return style_contains_disallowed_urls?(attribute_value) if attribute_name == 'style'
+    return svg_url_function_disallowed?(attribute_value) if attribute_value.match?(/url\s*\(/i)
+
+    false
+  end
+
+  def self.external_svg_url?(value)
+    stripped = value.to_s.strip
+    return false if stripped.blank? || stripped.start_with?('#')
+
+    true
+  end
+
+  def self.style_contains_disallowed_urls?(value)
+    text = value.to_s
+    text.match?(/@import/i) || svg_url_function_disallowed?(text)
+  end
+
+  def self.svg_url_function_disallowed?(value)
+    value.to_s.scan(/url\s*\(([^)]*)\)/i).flatten.any? do |entry|
+      reference =
+          entry.to_s.strip
+               .delete_prefix("'")
+               .delete_prefix('"')
+               .delete_suffix("'")
+               .delete_suffix('"')
+      reference.present? && !(reference.start_with?('#'))
+    end
+  end
+
+  def self.svg_dimensions(root)
+    width = svg_length_to_pixels(root['width'])
+    height = svg_length_to_pixels(root['height'])
+    return [width, height] if width && height
+
+    view_box = root['viewBox'].to_s.strip.split(/\s+/).map { Float(_1) rescue nil }
+    return [nil, nil] if view_box.length != 4 || view_box.any?(&:nil?)
+    return [nil, nil] unless view_box[2].finite? && view_box[2].positive?
+    return [nil, nil] unless view_box[3].finite? && view_box[3].positive?
+
+    [view_box[2], view_box[3]]
+  end
+
+  def self.svg_length_to_pixels(value)
+    return nil if value.blank?
+
+    matched = /\A([0-9]+(?:\.[0-9]+)?)(px)?\z/i.match(value.to_s.strip)
+    return nil if matched == nil
+
+    pixels = Float(matched[1])
+    return nil unless pixels.finite? && pixels.positive?
+
+    pixels
+  rescue ArgumentError
+    nil
+  end
+
+  private_class_method :image_for_thumbnail_upload,
+                       :svg_content_type?,
+                       :decode_raster_thumbnail,
+                       :decode_svg_thumbnail,
+                       :raster_thumbnail_format,
+                       :sanitised_svg_bytes,
+                       :svg_uses_disallowed_features?,
+                       :external_svg_reference?,
+                       :external_svg_url?,
+                       :style_contains_disallowed_urls?,
+                       :svg_url_function_disallowed?,
+                       :svg_dimensions,
+                       :svg_length_to_pixels
+
   def parse_original_created_value field
     raw_value = public_send("#{ field }_before_type_cast")
     value = public_send(field)
@@ -238,7 +429,8 @@ class Post < ApplicationRecord
     value = raw_value.to_s.strip
     return nil if value.blank?
 
-    if (match = value.match(/\A(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})\z/))
+    match = value.match(/\A(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})\z/)
+    if match
       year = match[1].to_i
       month = match[2].to_i
       day = match[3].to_i
@@ -251,9 +443,12 @@ class Post < ApplicationRecord
 
     match =
         value.match(
-            /\A(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})/ \
-            '(?::(\d{2})(?:\.(\d+))?)?' \
-            '(Z|[+-]\d{2}:?\d{2})?\z/')
+            /
+              \A(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})
+              (?::(\d{2})(?:\.(\d+))?)?
+              (Z|[+-]\d{2}:?\d{2})?
+              \z
+            /x)
     return nil if match.nil?
 
     year = match[1].to_i

backend/app/representations/post_compact_repr.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+
+module PostCompactRepr
+  module_function
+
+  def base post, host: nil
+    return nil if post.nil?
+
+    PostRepr
+        .common(post, host:)
+        .slice(
+            'id',
+            'title',
+            'url',
+            'thumbnail',
+            'thumbnail_base')
+  end
+end

backend/app/representations/post_repr.rb

@@ -17,8 +17,13 @@ module PostRepr
 
   module_function
 
-  def base post, current_user = nil
-    json = common(post)
+  def base post, current_user = nil, host: nil
+    json =
+        if host.present?
+          common(post, host:)
+        else
+          common(post)
+        end
     json['tags'] = tag_json(post)
     json['uploaded_user'] = post.uploaded_user && UserRepr.base(post.uploaded_user)
     json['viewed'] = current_user ? current_user.viewed?(post) : false
@@ -26,31 +31,59 @@ module PostRepr
   end
 
   def detail post, current_user = nil, parent_posts: [], child_posts: [],
-             sibling_posts: { }, related: []
-    base(post, current_user).merge(
-        'parent_posts' => cards(parent_posts),
-        'child_posts' => cards(child_posts),
-        'sibling_posts' => sibling_posts.transform_keys(&:to_s).transform_values { |posts|
-          cards(posts)
-        },
-        'related' => cards(related))
+             sibling_posts: { }, related: [], host: nil
+    if host.present?
+      base(post, current_user, host:).merge(
+          'parent_posts' => cards(parent_posts, host:),
+          'child_posts' => cards(child_posts, host:),
+          'sibling_posts' => sibling_posts.transform_keys(&:to_s).transform_values { |posts|
+            cards(posts, host:)
+          },
+          'related' => cards(related, host:))
+    else
+      base(post, current_user).merge(
+          'parent_posts' => cards(parent_posts),
+          'child_posts' => cards(child_posts),
+          'sibling_posts' => sibling_posts.transform_keys(&:to_s).transform_values { |posts|
+            cards(posts)
+          },
+          'related' => cards(related))
+    end
   end
 
-  def card post
-    common(post).merge('parent_posts' => [], 'child_posts' => [])
+  def card post, host: nil
+    if host.present?
+      common(post, host:).merge('parent_posts' => [], 'child_posts' => [])
+    else
+      common(post).merge('parent_posts' => [], 'child_posts' => [])
+    end
   end
 
-  def cards posts
-    posts.map { |post| card(post) }
+  def cards posts, host: nil
+    if host.present?
+      posts.map { |post| card(post, host:) }
+    else
+      posts.map { |post| card(post) }
+    end
   end
 
-  def many posts, current_user = nil
-    posts.map { |p| base(p, current_user) }
+  def many posts, current_user = nil, host: nil
+    if host.present?
+      posts.map { |p| base(p, current_user, host:) }
+    else
+      posts.map { |p| base(p, current_user) }
+    end
   end
 
-  def common post
+  def common post, host: nil
     BASE_FIELDS.to_h { |field| [field.to_s, post.public_send(field)] }
-               .merge('thumbnail' => thumbnail_url(post))
+               .merge(
+                   'thumbnail' =>
+                       if host.present?
+                         thumbnail_url(post, host:)
+                       else
+                         thumbnail_url(post)
+                       end)
   end
 
   def tag_json post
@@ -65,11 +98,22 @@ module PostRepr
     }
   end
 
-  def thumbnail_url post
+  def thumbnail_url post, host: nil
     return nil unless post.thumbnail.attached?
 
-    Rails.application.routes.url_helpers.rails_blob_url(post.thumbnail, only_path: false)
-  rescue
+    options = { only_path: false }
+    options[:host] = host if host.present?
+
+    Rails.application.routes.url_helpers.rails_storage_proxy_url(post.thumbnail, **options)
+  rescue ActionController::UrlGenerationError, ArgumentError, URI::InvalidURIError => e
+    payload = {
+        post_id: post.id,
+        attachment_id: post.thumbnail.attachment&.id,
+        blob_id: post.thumbnail.blob&.id,
+        error_class: e.class,
+        message: e.message }
+
+    Rails.logger.warn("PostRepr.thumbnail_url failed #{ payload.to_json }")
     nil
   end
 end

backend/app/services/post_bulk_creator.rb

@@ -0,0 +1,202 @@
+class PostBulkCreator
+  def initialize actor:, posts:, thumbnails:, host: nil
+    @actor_id = actor.id
+    @posts = posts
+    @thumbnails = thumbnails
+    @host = host
+  end
+
+  def run
+    results = Array.new(@posts.length)
+    mutex = Mutex.new
+    next_index = 0
+
+    workers = Array.new(2) do
+      Thread.new do
+        Rails.application.executor.wrap do
+          ActiveRecord::Base.connection_pool.with_connection do
+            actor = User.find(@actor_id)
+            loop do
+              index = nil
+              begin
+                index = mutex.synchronize do
+                  current = next_index
+                  next_index += 1
+                  current
+                end
+                break if index >= @posts.length
+
+                attributes = @posts[index]
+                results[index] = create_row(actor, attributes, index)
+              rescue StandardError => e
+                Rails.logger.error(
+                    "post_bulk_creator_worker_failure #{ { error: e.class.name,
+                                                          message: e.message,
+                                                          index: }.to_json }")
+                results[index] = {
+                    status: 'failed',
+                    recoverable: false,
+                    errors: { base: ['登録中にエラーが発生しました．'] },
+                    base_errors: [] }
+              end
+            end
+          end
+        end
+      end
+    end
+    workers.each(&:join)
+
+    results.each_index do |index|
+      next if results[index].present?
+
+      results[index] = {
+          status: 'failed',
+          recoverable: false,
+          errors: { base: ['登録中にエラーが発生しました．'] },
+          base_errors: [] }
+    end
+
+    { results: }
+  end
+
+  private
+
+  def create_row actor, attributes, index
+    preflight =
+        PostCreatePreflight.new(
+            attributes: attributes,
+            thumbnail: thumbnail_for(index, attributes),
+            host: @host).run
+    if preflight[:existing_post_id].present?
+      return {
+          status: 'skipped',
+          existing_post_id: preflight[:existing_post_id],
+          existing_post: preflight[:existing_post] }
+    end
+
+    post = PostCreator.new(
+        actor: actor,
+        attributes: normalised_attributes(attributes, preflight, index)).create!
+    result = {
+        status: 'created',
+        post: { id: post.id } }
+    result[:field_warnings] = preflight[:field_warnings] if preflight[:field_warnings].present?
+    result[:base_warnings] = preflight[:base_warnings] if preflight[:base_warnings].present?
+    result
+  rescue PostCreatePreflight::ValidationFailed => e
+    {
+        status: 'failed',
+        recoverable: true,
+        errors: e.fields,
+        base_errors: e.base_errors }
+  rescue ActiveRecord::RecordInvalid => e
+    existing_post = existing_post_for_race(attributes, e.record)
+    if existing_post.present?
+      return {
+          status: 'skipped',
+          existing_post_id: existing_post[:id],
+          existing_post: existing_post }
+    end
+
+    {
+        status: 'failed',
+        recoverable: true,
+        errors: e.record.errors.to_hash,
+        base_errors: e.record.errors[:base] }
+  rescue ActiveRecord::RecordNotUnique => e
+    if e.message.include?('index_posts_on_url')
+      existing_post = existing_post_for_race(attributes)
+      return {
+          status: 'skipped',
+          existing_post_id: existing_post[:id],
+          existing_post: existing_post } if existing_post.present?
+    end
+
+    Rails.logger.error(
+        "post_bulk_creator_record_not_unique #{ { error: e.class.name,
+                                                 message: e.message }.to_json }")
+    {
+        status: 'failed',
+        recoverable: false,
+        errors: { base: ['登録中にエラーが発生しました．'] },
+        base_errors: [] }
+  rescue Tag::NicoTagNormalisationError
+    {
+        status: 'failed',
+        recoverable: true,
+        errors: { tags: ['ニコニコ・タグは直接指定できません．'] },
+        base_errors: [] }
+  rescue Tag::DeprecatedTagNormalisationError
+    {
+        status: 'failed',
+        recoverable: true,
+        errors: { tags: ['廃止済みタグは付与できません．'] },
+        base_errors: [] }
+  rescue PostCreator::VideoMsParseError
+    {
+        status: 'failed',
+        recoverable: true,
+        errors: { video_ms: ['動画時間の記法が不正です．'] },
+        base_errors: [] }
+  rescue Post::RemoteThumbnailFetchFailed
+    {
+        status: 'failed',
+        recoverable: true,
+        errors: { thumbnail_base: ['サムネイル画像の取得に失敗しました．'] },
+        base_errors: [] }
+  rescue ArgumentError => e
+    {
+        status: 'failed',
+        recoverable: true,
+        errors: { base: [e.message] },
+        base_errors: [] }
+  rescue StandardError => e
+    Rails.logger.error(
+        "post_bulk_creator_failure #{ { error: e.class.name,
+                                        message: e.message }.to_json }")
+    {
+        status: 'failed',
+        recoverable: false,
+        errors: { base: ['登録中にエラーが発生しました．'] },
+        base_errors: [] }
+  end
+
+  def normalised_attributes attributes, preflight, index
+    {
+        url: preflight[:url],
+        title: preflight[:title],
+        thumbnail_base: preflight[:thumbnail_base],
+        thumbnail: thumbnail_for(index, attributes),
+        tags: preflight[:tags],
+        parent_post_ids: preflight[:parent_post_ids],
+        original_created_from: preflight[:original_created_from],
+        original_created_before: preflight[:original_created_before],
+        duration: preflight[:duration],
+        video_ms: preflight[:video_ms],
+        direct_tag_specs: preflight[:direct_tag_specs],
+        default_tag_specs: preflight[:default_tag_specs],
+        snapshot_tag_specs: preflight[:snapshot_tag_specs],
+        post_tag_specs: preflight[:post_tag_specs],
+        tag_sections: preflight[:tag_sections],
+        normalised_parent_post_ids: preflight[:normalised_parent_post_ids] }
+  end
+
+  def thumbnail_for index, attributes
+    return nil if attributes['thumbnail_base'].present? || attributes[:thumbnail_base].present?
+
+    @thumbnails[index]
+  end
+
+  def existing_post_for_race attributes, record = nil
+    return nil if record.present? && !(record.errors.of_kind?(:url, :taken))
+
+    normal_url = PostUrlNormaliser.normalise(attributes['url'] || attributes[:url])
+    return nil if normal_url.blank?
+
+    compact_existing_post(Post.with_attached_thumbnail.find_by(url: normal_url))
+  end
+
+  def compact_existing_post post
+    PostCompactRepr.base(post, host: @host)
+  end
+end

backend/app/services/post_create_plan.rb

@@ -0,0 +1,271 @@
+class PostCreatePlan
+  VIDEO_TAG_NAME = '動画'.freeze
+  TAGME_TAG_NAME = 'タグ希望'.freeze
+  NO_DEERJIKIST_TAG_NAME = 'ニジラー情報不詳'.freeze
+
+  def initialize attributes:
+    @attributes = attributes.symbolize_keys
+    @existing_tags_by_name = nil
+  end
+
+  def build!
+    direct_tag_specs, tag_sections = parse_direct_tag_specs
+    default_tag_specs = build_default_tag_specs(direct_tag_specs)
+    snapshot_tag_specs = merge_tag_specs(direct_tag_specs + default_tag_specs)
+    preload_existing_tags_by_name!(snapshot_tag_specs.map { _1[:name] })
+    validate_new_tag_specs!(snapshot_tag_specs)
+    post_tag_specs = expand_parent_tag_specs(snapshot_tag_specs)
+    video_ms = normalise_video_ms(snapshot_tag_specs)
+    validate_video_sections!(video_ms, tag_sections)
+    parent_post_ids = normalise_parent_post_ids
+    validate_parent_post_ids!(parent_post_ids)
+
+    {
+        url: @attributes[:url],
+        title: @attributes[:title].to_s,
+        thumbnail_base: @attributes[:thumbnail_base].presence,
+        original_created_from: @attributes[:original_created_from].presence,
+        original_created_before: @attributes[:original_created_before].presence,
+        tags: serialised_tags(direct_tag_specs, tag_sections),
+        display_tags: display_tags(direct_tag_specs, tag_sections),
+        duration: @attributes[:duration].to_s,
+        video_ms: video_ms,
+        parent_post_ids: parent_post_ids.join(' '),
+        direct_tag_specs: direct_tag_specs,
+        default_tag_specs: default_tag_specs,
+        snapshot_tag_specs: snapshot_tag_specs,
+        post_tag_specs: post_tag_specs,
+        tag_sections: tag_sections,
+        normalised_parent_post_ids: parent_post_ids }
+  end
+
+  private
+
+  def tag_names = @attributes[:tags].to_s.split
+
+  def parse_direct_tag_specs
+    tag_sections = { }
+    direct_tag_specs = []
+
+    tag_names.each do |raw_name|
+      tag_name, category, sections = parse_raw_tag_name(raw_name)
+      existing_tag = existing_tags_by_name[tag_name]
+      raise Tag::NicoTagNormalisationError if existing_tag&.nico?
+      raise Tag::DeprecatedTagNormalisationError, [existing_tag.name] if existing_tag&.deprecated?
+
+      direct_tag_specs << {
+          name: tag_name,
+          category: (category || existing_tag&.category || 'general').to_sym }
+      if sections.present?
+        tag_sections[tag_name] ||= []
+        tag_sections[tag_name].concat(sections)
+        tag_sections[tag_name] = Tag.merge_section_ranges(tag_sections[tag_name])
+        tag_sections.delete(tag_name) if tag_sections[tag_name] == [[0, nil]]
+      end
+    end
+
+    [merge_tag_specs(direct_tag_specs), tag_sections]
+  end
+
+  def parse_raw_tag_name raw_name
+    name = raw_name.to_s
+    prefix, category =
+        Tag::CATEGORY_PREFIXES.find {
+          name.downcase.start_with?(_1[0])
+        } || ['', nil]
+    name = name.sub(/\A#{ prefix }/i, '')
+
+    sections = []
+    while (match = name.match(/\A(\S*?)\[([^\[\]\s]*)-([^\[\]\s]*)\](\S*)\z/))
+      name = "#{ match[1] }#{ match[4] }"
+      next if match[2].empty? && match[3].empty?
+
+      sections << Tag.normalise_section_range!(
+          begin_raw: match[2],
+          end_raw: match[3],
+          tag_name: name)
+    end
+    if name.include?('[') || name.include?(']')
+      raise Tag::SectionLiteralParseError.new(raw_name, raw_name)
+    end
+
+    [resolved_tag_name(name), category&.to_sym, sections]
+  end
+
+  def build_default_tag_specs direct_tag_specs
+    default_tag_specs = []
+    if direct_tag_specs.length < 10 && direct_tag_specs.none? { _1[:name] == TAGME_TAG_NAME }
+      default_tag_specs << {
+          name: TAGME_TAG_NAME,
+          category: :meta }
+    end
+    if direct_tag_specs.none? { deerjikist_tag_spec?(_1) }
+      default_tag_specs << {
+          name: NO_DEERJIKIST_TAG_NAME,
+          category: :meta }
+    end
+
+    default_tag_specs
+  end
+
+  def validate_new_tag_specs! specs
+    Array(specs).each do |spec|
+      next if existing_tags_by_name.key?(spec[:name])
+
+      validate_new_tag_spec!(spec)
+    end
+  end
+
+  def validate_new_tag_spec! spec
+    tag_name = TagName.new(name: spec[:name])
+    tag = Tag.new(category: spec[:category], tag_name:)
+    return if tag_name.valid? && tag.valid?
+
+    post = Post.new
+    tag_name.errors[:name].each do |message|
+      post.errors.add :tags, "#{ spec[:name] }: #{ message }"
+    end
+    tag.errors.each do |error|
+      next if error.attribute == :tag_name
+
+      post.errors.add :tags, "#{ spec[:name] }: #{ error.message }"
+    end
+    raise ActiveRecord::RecordInvalid, post
+  end
+
+  def expand_parent_tag_specs snapshot_tag_specs
+    existing_snapshot_tags = snapshot_tag_specs.filter_map { existing_tags_by_name[_1[:name]] }
+    expanded_parent_specs =
+        Tag.expand_parent_tags(existing_snapshot_tags)
+           .reject(&:deprecated?)
+           .map { |tag|
+             {
+                 name: tag.name,
+                 category: tag.category.to_sym } }
+    merge_tag_specs(snapshot_tag_specs + expanded_parent_specs)
+  end
+
+  def merge_tag_specs specs
+    specs.each_with_object({ }) do |spec, merged|
+      merged[spec[:name]] =
+          if merged.key?(spec[:name]) && merged[spec[:name]][:category] != :general
+            merged[spec[:name]]
+          else
+            {
+                name: spec[:name],
+                category: spec[:category] }
+          end
+    end.values.sort_by { _1[:name] }
+  end
+
+  def existing_tags_by_name
+    @existing_tags_by_name ||= begin
+      names = tag_names.map { canonical_tag_name_without_sections(_1) }.uniq
+      Tag.joins(:tag_name).where(tag_names: { name: names }).index_by(&:name)
+    end
+  end
+
+  def preload_existing_tags_by_name! names
+    wanted_names = Array(names).map { _1.to_s }.reject(&:blank?).uniq
+    missing_names = wanted_names - existing_tags_by_name.keys
+    return if missing_names.empty?
+
+    existing_tags_by_name.merge!(
+        Tag.joins(:tag_name)
+           .where(tag_names: { name: missing_names })
+           .index_by(&:name))
+  end
+
+  def canonical_tag_name_without_sections raw_name
+    name, = parse_raw_tag_name(raw_name)
+    name
+  end
+
+  def deerjikist_tag_spec? spec
+    return true if spec[:category] == :deerjikist
+
+    existing_tags_by_name[spec[:name]]&.deerjikist?
+  end
+
+  def normalise_parent_post_ids
+    Array(@attributes[:parent_post_ids]).flat_map { _1.to_s.split }.map { |token|
+      id = Integer(token, exception: false)
+      raise ArgumentError, "親投稿 Id. が不正です: #{ token }" if id.nil? || id <= 0
+
+      id
+    }.uniq.sort
+  end
+
+  def validate_parent_post_ids! ids
+    missing = ids - Post.where(id: ids).pluck(:id)
+    raise ArgumentError, "存在しない親投稿 Id. があります: #{ missing.join(' ') }" if missing.present?
+  end
+
+  def serialised_tags direct_tag_specs, tag_sections
+    direct_tag_specs.map { |spec|
+      "#{ spec[:name] }#{ tag_sections[spec[:name]].to_a.map { section_literal(_1) }.join }"
+    }.sort.join(' ')
+  end
+
+  def display_tags direct_tag_specs, tag_sections
+    direct_tag_specs.map { |spec|
+      {
+          name: spec[:name],
+          category: spec[:category].to_s,
+          section_literals: tag_sections[spec[:name]].to_a.map { section_literal(_1) } }
+    }.sort_by { _1[:name] }
+  end
+
+  def section_literal range
+    begin_ms, end_ms = range
+    "[#{ Post.ms_to_time(begin_ms) }-#{ end_ms ? Post.ms_to_time(end_ms) : '' }]"
+  end
+
+  def normalise_video_ms snapshot_tag_specs
+    return nil unless snapshot_tag_specs.any? { _1[:name] == VIDEO_TAG_NAME }
+
+    video_ms = @attributes[:video_ms]
+    if video_ms.present?
+      value = Integer(video_ms, exception: false)
+      raise PostCreator::VideoMsParseError unless value&.positive?
+
+      return value
+    end
+
+    duration = @attributes[:duration]
+    return nil if duration.blank?
+
+    value = Tag.time_to_ms!(duration.to_s, tag_name: '動画時間')
+    raise PostCreator::VideoMsParseError unless value.positive?
+
+    value
+  rescue Tag::SectionLiteralParseError
+    raise PostCreator::VideoMsParseError
+  end
+
+  def validate_video_sections! video_ms, tag_sections
+    return unless video_ms
+
+    tag_sections.each_value do |ranges|
+      ranges.each do |begin_ms, end_ms|
+        if begin_ms >= video_ms
+          post = Post.new
+          post.errors.add :video_ms, 'タグ区間の開始が動画時間以上です．'
+          raise ActiveRecord::RecordInvalid, post
+        end
+        if end_ms && end_ms > video_ms
+          post = Post.new
+          post.errors.add :video_ms, 'タグ区間の終端が動画時間を超えてゐます．'
+          raise ActiveRecord::RecordInvalid, post
+        end
+      end
+    end
+  end
+
+  def resolved_tag_name name
+    tag_name = TagName.includes(:canonical).find_by(name:)
+    return name if tag_name.nil?
+
+    (tag_name.canonical || tag_name).name
+  end
+end

backend/app/services/post_create_preflight.rb

@@ -0,0 +1,141 @@
+class PostCreatePreflight
+  class ValidationFailed < StandardError
+    attr_reader :fields, :base_errors
+
+    def initialize fields: { }, base_errors: []
+      super('入力内容を確認してください．')
+      @fields = fields
+      @base_errors = base_errors
+    end
+  end
+
+  def initialize attributes:, thumbnail: nil, host: nil
+    @attributes = attributes.symbolize_keys
+    @thumbnail = thumbnail
+    @host = host
+  end
+
+  def run
+    preview = PostImportPreviewer.new.preview_rows(
+        rows: [preview_row],
+        fetch_metadata: false).first
+    if preview[:existing_post_id].present?
+      return {
+          url: preview[:url],
+          title: preview[:attributes]['title'],
+          thumbnail_base: preview[:attributes]['thumbnail_base'],
+          tags: preview[:attributes]['tags'],
+          parent_post_ids: preview[:attributes]['parent_post_ids'],
+          original_created_from: preview[:attributes]['original_created_from'],
+          original_created_before: preview[:attributes]['original_created_before'],
+          duration: preview[:attributes]['duration'],
+          video_ms: preview[:attributes]['video_ms'],
+          display_tags: preview[:display_tags] || [],
+          field_warnings: final_field_warnings(preview[:field_warnings] || { }),
+          base_warnings: preview[:base_warnings],
+          existing_post_id: preview[:existing_post_id],
+          existing_post: existing_post_compact(preview[:existing_post_id]) }
+    end
+
+    if preview[:validation_errors].present?
+      raise ValidationFailed.new(fields: preview[:validation_errors])
+    end
+
+    validate_thumbnail_upload!
+
+    plan = PostCreatePlan.new(
+        attributes: {
+            url: preview[:url],
+            title: preview[:attributes]['title'],
+            thumbnail_base: preview[:attributes]['thumbnail_base'],
+            tags: preview[:attributes]['tags'],
+            parent_post_ids: preview[:attributes]['parent_post_ids'],
+            original_created_from: preview[:attributes]['original_created_from'],
+            original_created_before: preview[:attributes]['original_created_before'],
+            duration: preview[:attributes]['duration'],
+            video_ms: preview[:attributes]['video_ms'] }).build!
+
+    {
+        url: plan[:url],
+        title: plan[:title],
+        thumbnail_base: plan[:thumbnail_base],
+        tags: plan[:tags],
+        parent_post_ids: plan[:parent_post_ids],
+        original_created_from: plan[:original_created_from],
+        original_created_before: plan[:original_created_before],
+        duration: plan[:duration],
+        video_ms: plan[:video_ms],
+        display_tags: plan[:display_tags],
+        direct_tag_specs: plan[:direct_tag_specs],
+        default_tag_specs: plan[:default_tag_specs],
+        snapshot_tag_specs: plan[:snapshot_tag_specs],
+        post_tag_specs: plan[:post_tag_specs],
+        tag_sections: plan[:tag_sections],
+        normalised_parent_post_ids: plan[:normalised_parent_post_ids],
+        field_warnings: final_field_warnings(preview[:field_warnings] || { }),
+        base_warnings: preview[:base_warnings],
+        existing_post_id: preview[:existing_post_id],
+        existing_post: existing_post_compact(preview[:existing_post_id]) }
+  end
+
+  private
+
+  def preview_row
+    {
+        source_row: 1,
+        url: @attributes[:url].to_s,
+        attributes: {
+            'title' => @attributes[:title].to_s,
+            'thumbnail_base' => @attributes[:thumbnail_base].to_s,
+            'original_created_from' => @attributes[:original_created_from].to_s,
+            'original_created_before' => @attributes[:original_created_before].to_s,
+            'duration' => @attributes[:duration].to_s,
+            'video_ms' => @attributes[:video_ms],
+            'tags' => @attributes[:tags].to_s,
+            'parent_post_ids' => parent_post_ids_text },
+        provenance: {
+            'url' => 'manual',
+            'title' => 'manual',
+            'thumbnail_base' => 'manual',
+            'original_created_from' => 'manual',
+            'original_created_before' => 'manual',
+            'duration' => 'manual',
+            'video_ms' => 'manual',
+            'tags' => 'manual',
+            'parent_post_ids' => 'manual' },
+        tag_sources: {
+            'automatic' => '',
+            'manual' => @attributes[:tags].to_s } }
+  end
+
+  def parent_post_ids_text
+    Array(@attributes[:parent_post_ids]).flat_map { _1.to_s.split }.join(' ')
+  end
+
+  def validate_thumbnail_upload!
+    return if @attributes[:thumbnail_base].present?
+    return if @thumbnail.blank?
+
+    PostThumbnailUploadValidator.validate!(@thumbnail)
+  rescue PostThumbnailUploadValidator::InvalidUpload => e
+    raise ValidationFailed.new(fields: { thumbnail: [e.message] })
+  end
+
+  def existing_post_compact post_id
+    return nil if post_id.blank?
+
+    post = Post.with_attached_thumbnail.find_by(id: post_id)
+    PostCompactRepr.base(post, host: @host)
+  end
+
+  def final_field_warnings field_warnings
+    thumbnail_warnings = (field_warnings['thumbnail_base'] || []).reject { _1 == 'サムネールなし' }
+    if @attributes[:thumbnail_base].blank? && @thumbnail.blank?
+      thumbnail_warnings = (thumbnail_warnings + ['サムネールなし']).uniq
+    end
+
+    next_warnings = field_warnings.except('thumbnail_base')
+    next_warnings['thumbnail_base'] = thumbnail_warnings if thumbnail_warnings.present?
+    next_warnings
+  end
+end

backend/app/services/post_creator.rb

@@ -10,97 +10,114 @@ class PostCreator
   end
 
   def create!
+    thumbnail_attachment = prepare_thumbnail_attachment
     post = Post.new(title: @attributes[:title].presence,
                     url: @attributes[:url],
                     thumbnail_base: @attributes[:thumbnail_base].presence,
                     uploaded_user: @actor,
                     original_created_from: @attributes[:original_created_from].presence,
                     original_created_before: @attributes[:original_created_before].presence)
-    attach_thumbnail!(post)
 
     ApplicationRecord.transaction do
       post.save!
-      Tag.normalise_tags!(tag_names, deny_deprecated: true, with_sections: true) =>
-          { tags:, sections: }
-      TagVersioning.record_tag_snapshots!(tags, created_by_user: @actor)
-      tags = Tag.expand_parent_tags(tags).reject(&:deprecated?)
-      post.video_ms = normalise_video_ms(tags)
-      validate_video_sections!(post.video_ms, sections)
+      post.thumbnail.attach(thumbnail_attachment) if thumbnail_attachment.present?
+      snapshot_tags = planned_snapshot_tags
+      post_tags = planned_post_tags
+      sections = planned_sections
+      TagVersioning.record_tag_snapshots!(snapshot_tags, created_by_user: @actor)
+      post.video_ms = planned_video_ms
       post.save!
-      sync_post_tags!(post, tags, sections)
-      sync_parent_posts!(post, parent_post_ids)
+      sync_post_tags!(post, post_tags, sections)
+      sync_parent_posts!(post, planned_parent_post_ids)
       PostVersionRecorder.record!(post:, event_type: :create, created_by_user: @actor)
     end
     post
+  rescue StandardError
+    post&.thumbnail&.purge if post&.thumbnail&.attached?
+    raise
   end
 
   private
 
-  def attach_thumbnail! post
-    thumbnail = @attributes[:thumbnail]
-    if thumbnail.present?
-      post.thumbnail.attach(Post.resized_thumbnail_attachment(thumbnail))
-      return
-    end
-
-    thumbnail_base = post.thumbnail_base
-    return if thumbnail_base.blank?
-
-    post.attach_thumbnail_from_url!(thumbnail_base)
-  rescue Post::RemoteThumbnailFetchFailed => e
-    @field_warnings[:thumbnail_base] = [e.message]
+  def prepare_thumbnail_attachment
+    PostThumbnailAttachmentBuilder.build(
+        thumbnail: @attributes[:thumbnail],
+        thumbnail_base: @attributes[:thumbnail_base].presence)
   end
 
-  def tag_names = @attributes[:tags].to_s.split
+  def planned_snapshot_tags = planned_create_attributes[:snapshot_tags]
 
-  def parent_post_ids
-    Array(@attributes[:parent_post_ids]).flat_map { _1.to_s.split }.map { |token|
-      id = Integer(token, exception: false)
-      raise ArgumentError, "親投稿 Id. が不正です: #{ token }" if id.nil? || id <= 0
+  def planned_post_tags = planned_create_attributes[:post_tags]
 
-      id
-    }.uniq
+  def planned_sections = planned_create_attributes[:tag_sections]
+
+  def planned_parent_post_ids = planned_create_attributes[:normalised_parent_post_ids]
+
+  def planned_video_ms
+    planned_create_attributes[:video_ms]
   end
 
-  def normalise_video_ms tags
-    return nil unless tags.any? { _1.id == Tag.video.id }
-
-    video_ms = @attributes[:video_ms]
-    if video_ms.present?
-      value = Integer(video_ms, exception: false)
-      raise VideoMsParseError unless value&.positive?
-
-      return value
-    end
-    duration = @attributes[:duration]
-    return nil if duration.blank?
-
-    value = Tag.time_to_ms!(duration.to_s, tag_name: '動画時間')
-    raise VideoMsParseError unless value.positive?
-
-    value
-  rescue Tag::SectionLiteralParseError
-    raise VideoMsParseError
-  end
-
-  def validate_video_sections! video_ms, sections
-    return unless video_ms
-
-    sections.each_value do |ranges|
-      ranges.each do |begin_ms, end_ms|
-        post = Post.new
-        if begin_ms >= video_ms
-          post.errors.add :video_ms, 'タグ区間の開始が動画時間以上です．'
-          raise ActiveRecord::RecordInvalid, post
-        end
-        if end_ms && end_ms > video_ms
-          post.errors.add :video_ms, 'タグ区間の終端が動画時間を超えてゐます．'
-          raise ActiveRecord::RecordInvalid, post
-        end
+  def planned_create_attributes
+    @planned_create_attributes ||= begin
+      if @attributes.key?(:snapshot_tag_specs)
+        snapshot_tags = materialise_tags(@attributes[:snapshot_tag_specs] || [])
+        post_tags = materialise_tags(@attributes[:post_tag_specs] || [])
+        {
+            snapshot_tags: snapshot_tags,
+            post_tags: post_tags,
+            tag_sections: materialise_sections(
+                @attributes[:tag_sections] || { },
+                snapshot_tags,
+                post_tags),
+            normalised_parent_post_ids: @attributes[:normalised_parent_post_ids] || [],
+            video_ms: @attributes[:video_ms] }
+      else
+        build_materialised_plan
       end
     end
   end
 
+  def build_materialised_plan
+    plan = PostCreatePlan.new(attributes: @attributes).build!
+    snapshot_tags = materialise_tags(plan[:snapshot_tag_specs] || [])
+    post_tags = materialise_tags(plan[:post_tag_specs] || [])
+    {
+        snapshot_tags: snapshot_tags,
+        post_tags: post_tags,
+        tag_sections: materialise_sections(
+            plan[:tag_sections] || { },
+            snapshot_tags,
+            post_tags),
+        normalised_parent_post_ids: plan[:normalised_parent_post_ids] || [],
+        video_ms: plan[:video_ms] }
+  end
+
+  def materialise_tags specs
+    Array(specs).each_with_object({ }) do |spec, tags|
+      name = spec[:name] || spec['name']
+      category = spec[:category] || spec['category']
+      next if name.blank? || category.blank?
+
+      tag = Tag.find_or_create_by_tag_name!(name, category:)
+      tag.update!(category:) if tag.category.to_sym != category.to_sym
+      tags[name] ||= tag
+    end.values
+  end
+
+  def materialise_sections sections_by_name, snapshot_tags, post_tags
+    tags_by_name = post_tags.index_by(&:name)
+    snapshot_tags.each do |tag|
+      tags_by_name[tag.name] ||= tag
+    end
+
+    sections_by_name.each_with_object({ }) do |(tag_name, ranges), sections|
+      tag = tags_by_name[tag_name.to_s]
+      next if tag.nil?
+
+      sections[tag.id] = Array(ranges).map { |range| [range[0], range[1]] }
+    end
+  end
+
   def sync_post_tags! post, desired_tags, sections
     desired_ids = desired_tags.map(&:id).to_set
     current_ids = post.tags.pluck(:id).to_set

backend/app/services/post_import_previewer.rb

@@ -3,17 +3,18 @@ require 'timeout'
 
 class PostImportPreviewer
   FIELDS = [
-    'title',
-    'thumbnail_base',
-    'original_created_from',
-    'original_created_before',
-    'duration',
-    'tags',
-    'parent_post_ids'].freeze
+      'title',
+      'thumbnail_base',
+      'original_created_from',
+      'original_created_before',
+      'video_ms',
+      'duration',
+      'tags',
+      'parent_post_ids'].freeze
   FETCH_WARNING_FIELDS = ['url', 'title', 'thumbnail_base'].freeze
   TITLE_FETCH_WARNING = 'タイトルを取得できませんでした．'.freeze
   THUMBNAIL_FETCH_WARNING = 'サムネールを取得できませんでした．'.freeze
-  METADATA_FETCH_WARNING = 'メタデータを取得できませんでした．'.freeze
+  METADATA_FETCH_WARNING = '自動取得に失敗しました．'.freeze
 
   def preview_rows rows:, fetch_metadata: true, metadata_cache: { }
     prepared_rows = rows.map { prepare_row(_1) }
@@ -125,7 +126,6 @@ class PostImportPreviewer
     validate_basic_data(attributes, validation_errors)
     validate_preview_tags(merged_tags(tag_sources, provenance['tags']),
                           validation_errors,
-                          field_warnings,
                           known_tags)
     validate_parents(attributes['parent_post_ids'], validation_errors, existing_parent_ids)
     attributes.delete('url')
@@ -151,7 +151,7 @@ class PostImportPreviewer
     when true then true
     when Integer then fetch_metadata == source_row
     when false, nil then false
-    else raise ArgumentError, 'メタデータ取得対象が不正です．'
+    else raise ArgumentError, '取得対象が不正です．'
     end
   end
 
@@ -162,6 +162,8 @@ class PostImportPreviewer
       normalised =
           if field == 'duration'
             normalise_duration_attribute(value)
+          elsif field == 'video_ms'
+            value.nil? ? '' : value.to_s
           else
             value.to_s
           end
@@ -194,7 +196,7 @@ class PostImportPreviewer
 
   def clear_automatic_values! attributes, provenance, tag_sources
     ['title', 'thumbnail_base', 'original_created_from',
-     'original_created_before', 'duration'].each do |field|
+     'original_created_before', 'video_ms', 'duration'].each do |field|
       attributes[field] = '' if provenance[field] == 'automatic'
     end
     tag_sources['automatic'] = ''
@@ -223,15 +225,15 @@ class PostImportPreviewer
     end
     { data:, warnings:, validation_errors: { } }
   rescue Preview::UrlSafety::UnsafeUrl => e
+    payload = { error: e.class.name, message: e.message }
     Rails.logger.info(
-        "post_import_metadata_fetch_unsafe_url "\
-        "#{ { error: e.class.name, message: e.message }.to_json }")
+        "post_import_metadata_fetch_unsafe_url #{ payload.to_json }")
     { data: { }, warnings: { }, validation_errors: { url: [e.message] } }
   rescue Preview::HttpFetcher::FetchFailed,
          Preview::HttpFetcher::ResponseTooLarge => e
+    payload = { error: e.class.name, message: e.message }
     Rails.logger.info(
-        "post_import_metadata_fetch_failure "\
-        "#{ { error: e.class.name, message: e.message }.to_json }")
+        "post_import_metadata_fetch_failure #{ payload.to_json }")
     { data: { }, warnings: { 'url' => [METADATA_FETCH_WARNING] }, validation_errors: { } }
   end
 
@@ -252,7 +254,15 @@ class PostImportPreviewer
   def sanitise_metadata_url value
     return nil unless value.is_a?(String)
 
-    PostUrlNormaliser.normalise(value)
+    stripped = value.strip
+    return nil if stripped.blank?
+
+    uri = URI.parse(stripped)
+    return nil unless uri.is_a?(URI::HTTP) && uri.host.present?
+
+    stripped
+  rescue URI::InvalidURIError
+    nil
   end
 
   def sanitise_metadata_time value
@@ -325,14 +335,14 @@ class PostImportPreviewer
   def safe_fetch_metadata url
     fetch_metadata(url)
   rescue Preview::UrlSafety::UnsafeUrl => e
+    payload = { error: e.class.name, message: e.message }
     Rails.logger.info(
-        "post_import_metadata_fetch_unsafe_url "\
-        "#{ { error: e.class.name, message: e.message }.to_json }")
+        "post_import_metadata_fetch_unsafe_url #{ payload.to_json }")
     { data: { }, warnings: { }, validation_errors: { url: [e.message] } }
   rescue StandardError => e
+    payload = { error: e.class.name, message: e.message }
     Rails.logger.error(
-        "post_import_metadata_fetch_unexpected_failure "\
-        "#{ { error: e.class.name, message: e.message }.to_json }")
+        "post_import_metadata_fetch_unexpected_failure #{ payload.to_json }")
     { data: { }, warnings: { 'url' => [METADATA_FETCH_WARNING] }, validation_errors: { } }
   end
 
@@ -439,7 +449,7 @@ class PostImportPreviewer
     []
   end
 
-  def validate_preview_tags raw, errors, field_warnings, known_tags
+  def validate_preview_tags raw, errors, known_tags
     names = raw.to_s.split
     return if names.empty?
     if names.any? { _1.downcase.start_with?('nico:') }
@@ -451,11 +461,6 @@ class PostImportPreviewer
     existing = parsed.filter_map { known_tags[_1] }
     deprecated = existing.select(&:deprecated?).map(&:name)
     errors[:tags] = ["廃止済みタグがあります: #{ deprecated.join(' ') }"] if deprecated.present?
-    known = existing.reject(&:deprecated?).map(&:name)
-    new_tags = parsed.uniq - known
-    if new_tags.present?
-      add_field_warning!(field_warnings, 'tags', "新規タグを作成します: #{ new_tags.join(' ') }")
-    end
   rescue Tag::SectionLiteralParseError
     errors[:tags] = ['タグ区間の記法が不正です．']
   end
@@ -466,7 +471,7 @@ class PostImportPreviewer
                     thumbnail_base: attributes['thumbnail_base'].presence,
                     original_created_from: attributes['original_created_from'].presence,
                     original_created_before: attributes['original_created_before'].presence,
-                    video_ms: parse_duration(attributes['duration'], errors))
+                    video_ms: parse_video_ms(attributes, errors))
     post.valid?
     post.errors.each do |error|
       next if error.attribute == :url && error.type == :taken
@@ -475,7 +480,21 @@ class PostImportPreviewer
     end
   end
 
-  def parse_duration value, errors
+  def parse_video_ms attributes, errors
+    return nil unless attributes['tags'].to_s.split.include?('動画')
+
+    video_ms = attributes['video_ms']
+    if video_ms.present?
+      value = Integer(video_ms, exception: false)
+      if value&.positive?
+        return value
+      end
+
+      errors[:video_ms] = ['動画時間の記法が不正です．']
+      return nil
+    end
+
+    value = attributes['duration']
     return nil if value.blank?
 
     Tag.time_to_ms!(value.to_s, tag_name: '動画時間')

backend/app/services/post_import_row_normaliser.rb

@@ -1,190 +0,0 @@
-class PostImportRowNormaliser
-  ORIGINS = ['automatic', 'manual'].freeze
-  STRING_FIELDS = [
-    'title',
-    'thumbnail_base',
-    'original_created_from',
-    'original_created_before',
-    'duration',
-    'tags',
-    'parent_post_ids'].freeze
-  FLEXIBLE_FIELDS = ['video_ms'].freeze
-  ATTRIBUTE_FIELDS = (STRING_FIELDS + FLEXIBLE_FIELDS).freeze
-
-  def self.normalise! rows, allow_warning_fields: false
-    raise ArgumentError, '取込行の形式が不正です．' unless rows.is_a?(Array)
-    raise ArgumentError, '取込件数が多すぎます．' if rows.length > PostImportUrlListParser::MAX_ROWS
-
-    normalised_rows = rows.map { normalise_row!(_1, allow_warning_fields:) }
-    source_rows = normalised_rows.map { _1['source_row'] }
-    raise ArgumentError, '元行番号が重複しています．' if source_rows.uniq.length != source_rows.length
-    if normalised_rows.sum { row_bytesize(_1) } > PostImportUrlListParser::MAX_BYTES
-      raise ArgumentError, '取込データが大きすぎます．'
-    end
-
-    normalised_rows
-  end
-
-  def self.normalise_row! row, allow_warning_fields:
-    unless row.is_a?(Hash) || row.is_a?(ActionController::Parameters)
-      raise ArgumentError, '取込行の形式が不正です．'
-    end
-
-    parameters =
-        row.is_a?(ActionController::Parameters) ? row : ActionController::Parameters.new(row)
-    permitted = parameters.permit(*permitted_keys(allow_warning_fields))
-    normalised = permitted.to_h.deep_transform_keys { _1.to_s.underscore }
-
-    normalised['source_row'] = normalise_source_row!(normalised['source_row'])
-    normalise_url!(normalised['url'])
-    normalise_metadata_url!(normalised['metadata_url'])
-    normalise_attributes!(normalised.fetch('attributes', { }))
-    normalise_provenance!(normalised.fetch('provenance', { }))
-    normalise_tag_sources!(normalised['tag_sources'])
-    normalise_warning_values!(normalised, allow_warning_fields:)
-    if row_bytesize(normalised) > PostImportUrlListParser::MAX_BYTES
-      raise ArgumentError, '取込行が大きすぎます．'
-    end
-
-    normalised
-  end
-
-  def self.permitted_keys allow_warning_fields
-    keys = [
-      :source_row,
-      :sourceRow,
-      :url,
-      :metadata_url,
-      :metadataUrl,
-      { attributes: {} },
-      { provenance: {} },
-      { tag_sources: {} },
-      { tagSources: {} }]
-    return keys unless allow_warning_fields
-
-    keys + [
-      { field_warnings: {} },
-      { fieldWarnings: {} },
-      { base_warnings: [] },
-      { baseWarnings: [] }]
-  end
-  private_class_method :permitted_keys
-
-  def self.normalise_source_row! value
-    source_row = Integer(value, exception: false)
-    raise ArgumentError, '元行番号が不正です．' if source_row.nil? || source_row <= 0
-
-    source_row
-  end
-  private_class_method :normalise_source_row!
-
-  def self.normalise_url! value
-    unless value.is_a?(String)
-      raise ArgumentError, 'URL の形式が不正です．'
-    end
-    if value.bytesize > PostImportUrlListParser::MAX_URL_BYTES
-      raise ArgumentError, 'URL が長すぎます．'
-    end
-  end
-  private_class_method :normalise_url!
-
-  def self.normalise_metadata_url! value
-    raise ArgumentError, 'metadata_url の形式が不正です．' unless value.nil? || value.is_a?(String)
-    if value.to_s.bytesize > PostImportUrlListParser::MAX_URL_BYTES
-      raise ArgumentError, 'metadata_url が長すぎます．'
-    end
-  end
-  private_class_method :normalise_metadata_url!
-
-  def self.normalise_attributes! attributes
-    raise ArgumentError, 'attributes の形式が不正です．' unless attributes.is_a?(Hash)
-    raise ArgumentError, '取込項目が不正です．' unless (attributes.keys - ATTRIBUTE_FIELDS).empty?
-
-    attributes.each do |key, value|
-      case key
-      when *STRING_FIELDS
-        raise ArgumentError, '取込項目の型が不正です．' unless value.nil? || value.is_a?(String)
-      when *FLEXIBLE_FIELDS
-        unless value.nil? || value.is_a?(String) || value.is_a?(Numeric)
-          raise ArgumentError, '取込項目の型が不正です．'
-        end
-      end
-      if value.to_s.bytesize > PostImportUrlListParser::MAX_URL_BYTES
-        raise ArgumentError, '取込項目が大きすぎます．'
-      end
-    end
-  end
-  private_class_method :normalise_attributes!
-
-  def self.normalise_provenance! provenance
-    unless provenance.is_a?(Hash)
-      raise ArgumentError, 'provenance の形式が不正です．'
-    end
-
-    allowed = ATTRIBUTE_FIELDS + ['url']
-    unless (provenance.keys - allowed).empty?
-      raise ArgumentError, '値の由来が不正です．'
-    end
-    unless provenance.values.all? { ORIGINS.include?(_1) }
-      raise ArgumentError, '値の由来が不正です．'
-    end
-  end
-  private_class_method :normalise_provenance!
-
-  def self.normalise_tag_sources! tag_sources
-    return if tag_sources.nil?
-
-    unless tag_sources.is_a?(Hash)
-      raise ArgumentError, 'タグ由来の形式が不正です．'
-    end
-    unless (tag_sources.keys - ORIGINS).empty?
-      raise ArgumentError, 'タグ由来の形式が不正です．'
-    end
-    unless tag_sources.values.all? { _1.is_a?(String) }
-      raise ArgumentError, 'タグ由来の形式が不正です．'
-    end
-    if tag_sources.values.any? { _1.bytesize > PostImportUrlListParser::MAX_URL_BYTES }
-      raise ArgumentError, 'タグ由来が大きすぎます．'
-    end
-    if tag_sources.values.sum(&:bytesize) > PostImportUrlListParser::MAX_URL_BYTES
-      raise ArgumentError, 'タグ由来が大きすぎます．'
-    end
-  end
-  private_class_method :normalise_tag_sources!
-
-  def self.normalise_warning_values! normalised, allow_warning_fields:
-    return unless allow_warning_fields
-
-    field_warnings = normalised['field_warnings']
-    unless field_warnings.nil? || field_warnings.is_a?(Hash)
-      raise ArgumentError, '警告の形式が不正です．'
-    end
-    field_warnings&.each do |key, values|
-      unless ATTRIBUTE_FIELDS.include?(key) || key == 'url'
-        raise ArgumentError, '警告の形式が不正です．'
-      end
-      unless values.is_a?(Array) && values.all? { _1.is_a?(String) }
-        raise ArgumentError, '警告の形式が不正です．'
-      end
-      if values.any? { _1.bytesize > PostImportUrlListParser::MAX_URL_BYTES }
-        raise ArgumentError, '警告が大きすぎます．'
-      end
-    end
-
-    base_warnings = normalised['base_warnings']
-    return if base_warnings.nil?
-
-    unless base_warnings.is_a?(Array) && base_warnings.all? { _1.is_a?(String) }
-      raise ArgumentError, '警告の形式が不正です．'
-    end
-    if base_warnings.any? { _1.bytesize > PostImportUrlListParser::MAX_URL_BYTES }
-      raise ArgumentError, '警告が大きすぎます．'
-    end
-  end
-  private_class_method :normalise_warning_values!
-
-  def self.row_bytesize row
-    row.to_json.bytesize
-  end
-  private_class_method :row_bytesize
-end

backend/app/services/post_import_runner.rb

@@ -1,109 +0,0 @@
-class PostImportRunner
-  def initialize actor:, rows:
-    @actor = actor
-    @rows = rows
-  end
-
-  def run
-    normalised_rows = PostImportRowNormaliser.normalise!(@rows)
-    previews = PostImportPreviewer.new.preview_rows(rows: normalised_rows,
-                                                    fetch_metadata: false)
-    preview_map = previews.index_by { _1[:source_row] }
-
-    results = normalised_rows.map do |row|
-      run_row(row, preview_map.fetch(row['source_row']))
-    end
-
-    { created: results.count { _1[:status] == 'created' },
-      skipped: results.count { _1[:status] == 'skipped' },
-      failed: results.count { _1[:status] == 'failed' },
-      rows: results }
-  end
-
-  private
-
-  def run_row row, preview
-    attributes = row.fetch('attributes', { }).transform_keys { _1.to_s.underscore }
-    return { source_row: row['source_row'],
-             status: 'failed',
-             errors: preview[:validation_errors],
-             recoverable: true } if preview[:validation_errors].present?
-    if preview[:skip_reason] == 'existing'
-      return { source_row: row['source_row'],
-               status: 'skipped',
-               existing_post_id: preview[:existing_post_id] }
-    end
-
-    attributes['tags'] = preview[:attributes]['tags']
-    attributes['url'] = row['url']
-    creator = PostCreator.new(actor: @actor, attributes:)
-    post = creator.create!
-    result = { source_row: row['source_row'], status: 'created', post: PostRepr.base(post) }
-    if creator.field_warnings.present?
-      result[:field_warnings] = creator.field_warnings
-    end
-    result
-  rescue ActiveRecord::RecordInvalid => e
-    existing_post = existing_post_for_race(row, e.record)
-    if existing_post
-      return { source_row: row['source_row'],
-               status: 'skipped',
-               existing_post_id: existing_post.id }
-    end
-
-    { source_row: row['source_row'],
-      status: 'failed',
-      errors: e.record.errors.to_hash,
-      recoverable: true }
-  rescue ActiveRecord::RecordNotUnique => e
-    raise unless url_record_not_unique?(e)
-
-    existing_post = existing_post_for_race(row)
-    raise unless existing_post
-
-    { source_row: row['source_row'],
-      status: 'skipped',
-      existing_post_id: existing_post.id }
-  rescue Tag::NicoTagNormalisationError
-    { source_row: row['source_row'],
-      status: 'failed',
-      errors: { tags: ['ニコニコ・タグは直接指定できません．'] },
-      recoverable: true }
-  rescue Tag::DeprecatedTagNormalisationError
-    { source_row: row['source_row'],
-      status: 'failed',
-      errors: { tags: ['廃止済みタグは付与できません．'] },
-      recoverable: true }
-  rescue PostCreator::VideoMsParseError
-    { source_row: row['source_row'],
-      status: 'failed',
-      errors: { duration: ['動画時間の記法が不正です．'] },
-      recoverable: true }
-  rescue ArgumentError
-    { source_row: row['source_row'],
-      status: 'failed',
-      errors: { base: ['入力値が不正です．'] },
-      recoverable: true }
-  rescue StandardError => e
-    Rails.logger.error("post_import_runner_failure #{ { error: e.class.name,
-                                                        message: e.message }.to_json }")
-    { source_row: row['source_row'],
-      status: 'failed',
-      errors: { base: ['登録中にエラーが発生しました．'] } }
-  end
-
-  def existing_post_for_race row, record = nil
-    if record && !(record.errors.of_kind?(:url, :taken))
-      return nil
-    end
-
-    normal_url = PostUrlNormaliser.normalise(row['url'])
-    return nil if normal_url.blank?
-
-    Post.find_by(url: normal_url)
-  end
-
-  def url_record_not_unique? error
-    error.message.include?('index_posts_on_url')
-  end
-end

backend/app/services/post_import_url_list_parser.rb

@@ -1,25 +0,0 @@
-class PostImportUrlListParser
-  MAX_ROWS = 100
-  MAX_BYTES = 1.megabyte
-  MAX_URL_BYTES = 20.kilobytes
-
-  def self.parse source
-    raw = source.to_s
-    raise ArgumentError, '入力が大きすぎます．' if raw.bytesize > MAX_BYTES
-
-    rows = raw.split(/\r\n|\n|\r/).each_with_index.filter_map { |line, index|
-      url = line.strip
-      next if url.blank?
-
-      if url.bytesize > MAX_URL_BYTES
-        raise ArgumentError, "#{ index + 1 } 行目: URL が長すぎます．"
-      end
-
-      { source_row: index + 1, url: }
-    }
-    raise ArgumentError, 'URL を入力してください．' if rows.empty?
-    raise ArgumentError, "取込件数は #{ MAX_ROWS } 件までです．" if rows.length > MAX_ROWS
-
-    rows
-  end
-end

backend/app/services/post_metadata_fetcher.rb

@@ -3,10 +3,9 @@ require 'date'
 
 class PostMetadataFetcher
   TIMESTAMP_PATTERN =
-      Regexp.new(
-          '\A(\d{4})-(\d{2})-(\d{2})T(\d{2})' \
-          '(?::(\d{2})(?::(\d{2})(?:\.(\d+))?)?)?' \
-          '(Z|[+-]\d{2}:?\d{2})?\z')
+      /\A(\d{4})-(\d{2})-(\d{2})T(\d{2})
+        (?::(\d{2})(?::(\d{2})(?:\.(\d+))?)?)?
+        (Z|[+-]\d{2}:?\d{2})?\z/x
 
   def self.fetch raw_url
     uri, = Preview::UrlSafety.validate(raw_url)
@@ -32,6 +31,7 @@ class PostMetadataFetcher
       original_created_from: serialise_time(created_range&.first),
       original_created_before: serialise_time(created_range&.last),
       duration: serialise_duration(duration),
+      display_tags: display_tags(platform_tags),
       tags: platform_tags.join(' ') }
   end
 
@@ -42,6 +42,24 @@ class PostMetadataFetcher
     []
   end
 
+  def self.display_tags names
+    return [] if names.blank?
+
+    existing_tags =
+        Tag
+        .joins(:tag_name)
+        .where(tag_names: { name: names })
+        .index_by(&:name)
+
+    names.map { |name|
+      tag = existing_tags[name]
+      {
+          name: name,
+          category: (tag&.category || 'meta'),
+          section_literals: [] }
+    }
+  end
+
   def self.original_created_range value
     return nil if value.blank?
 
@@ -168,6 +186,7 @@ class PostMetadataFetcher
   end
 
   private_class_method :platform_tags,
+                       :display_tags,
                        :original_created_range,
                        :parse_timestamp_range,
                        :parse_nanoseconds,

backend/app/services/post_thumbnail_attachment_builder.rb

@@ -0,0 +1,11 @@
+class PostThumbnailAttachmentBuilder
+  def self.build thumbnail:, thumbnail_base:
+    if thumbnail_base.present?
+      return Post.remote_thumbnail_attachment(thumbnail_base)
+    end
+
+    return nil if thumbnail.blank?
+
+    Post.resized_thumbnail_attachment(thumbnail)
+  end
+end

backend/app/services/post_thumbnail_upload_validator.rb

@@ -0,0 +1,34 @@
+class PostThumbnailUploadValidator
+  MAX_THUMBNAIL_BYTES = 20 * 1024 * 1024
+  ALLOWED_CONTENT_TYPES = Preview::ThumbnailFetcher::RASTER_IMAGE_CONTENT_TYPES.freeze
+
+  class InvalidUpload < StandardError; end
+
+  def self.validate! thumbnail
+    return if thumbnail.blank?
+    unless thumbnail.is_a?(ActionDispatch::Http::UploadedFile)
+      raise InvalidUpload, 'thumbnail upload が不正です．'
+    end
+    raise InvalidUpload, 'thumbnail file size が大きすぎます．' if thumbnail.size > MAX_THUMBNAIL_BYTES
+    raise InvalidUpload, 'サムネイル画像の形式が不正です．' unless allowed_content_type?(thumbnail.content_type)
+    bytes = thumbnail.read
+    raise InvalidUpload, 'サムネイル画像の形式が不正です．' if Post.svg_document_bytes?(bytes)
+    unless Post.raster_thumbnail_bytes?(bytes)
+      raise InvalidUpload, 'サムネイル画像の形式が不正です．'
+    end
+
+    attachment = Post.resized_thumbnail_attachment(
+        StringIO.new(bytes),
+        content_type: thumbnail.content_type)
+    attachment[:io].close if attachment[:io].respond_to?(:close)
+  rescue MiniMagick::Error, Timeout::Error
+    raise InvalidUpload, 'サムネイル画像の変換に失敗しました．'
+  ensure
+    thumbnail&.rewind if thumbnail.respond_to?(:rewind)
+  end
+
+  def self.allowed_content_type? content_type
+    mime_type = content_type.to_s.split(';', 2).first.to_s.downcase.strip
+    ALLOWED_CONTENT_TYPES.include?(mime_type)
+  end
+end

backend/app/services/preview/thumbnail_fetcher.rb

@@ -1,7 +1,7 @@
 module Preview
   class ThumbnailFetcher
     class GenerationFailed < StandardError; end
-    ALLOWED_IMAGE_CONTENT_TYPES = [
+    RASTER_IMAGE_CONTENT_TYPES = [
       'image/jpeg', 'image/png', 'image/gif', 'image/webp'
     ].freeze
     HTML_MAX_BYTES = 1.megabyte
@@ -28,7 +28,9 @@ module Preview
     def self.fetch_image_response(raw_url)
       uri, = UrlSafety.validate(raw_url)
       response = HttpFetcher.fetch(uri.to_s)
-      unless allowed_image_content_type?(response.content_type)
+      unless Post.remote_thumbnail_image_bytes?(
+                 response.body,
+                 content_type: response.content_type)
         raise GenerationFailed, 'サムネール画像が見つかりませんでした．'
       end
 
@@ -51,7 +53,9 @@ module Preview
       return nil if url.blank?
 
       response = HttpFetcher.fetch(url)
-      return nil unless allowed_image_content_type?(response.content_type)
+      return nil unless Post.remote_thumbnail_image_bytes?(
+                            response.body,
+                            content_type: response.content_type)
 
       response.body
     rescue HttpFetcher::FetchTimeout
@@ -92,13 +96,7 @@ module Preview
       nil
     end
 
-    def self.allowed_image_content_type?(content_type)
-      mime_type = content_type.to_s.split(';', 2).first.downcase.strip
-      ALLOWED_IMAGE_CONTENT_TYPES.include?(mime_type)
-    end
-
     private_class_method :fetch_image_or_nil, :fetch_image!,
-                         :niconico_thumbnail_url,
-                         :allowed_image_content_type?
+                         :niconico_thumbnail_url
   end
 end

backend/config/environments/development.rb

@@ -1,4 +1,4 @@
-require "active_support/core_ext/integer/time"
+require 'active_support/core_ext/integer/time'
 
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
@@ -17,8 +17,8 @@ Rails.application.configure do
 
   # Enable/disable Action Controller caching. By default Action Controller caching is disabled.
   # Run rails dev:cache to toggle Action Controller caching.
-  if Rails.root.join("tmp/caching-dev.txt").exist?
-    config.public_file_server.headers = { "cache-control" => "public, max-age=#{2.days.to_i}" }
+  if Rails.root.join('tmp/caching-dev.txt').exist?
+    config.public_file_server.headers = { 'cache-control' => "public, max-age=#{2.days.to_i}" }
   else
     config.action_controller.perform_caching = false
   end
@@ -36,7 +36,11 @@ Rails.application.configure do
   config.action_mailer.perform_caching = false
 
   # Set localhost to be used by links generated in mailer templates.
-  config.action_mailer.default_url_options = { host: "localhost", port: 3000 }
+  config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
+  Rails.application.routes.default_url_options.merge!(
+      host: 'localhost',
+      port: 3002,
+      protocol: 'http')
 
   # Print deprecation notices to the Rails logger.
   config.active_support.deprecation = :log

backend/config/routes.rb

@@ -33,12 +33,6 @@ Rails.application.routes.draw do
     get :thumbnail
   end
 
-  scope 'posts/import', controller: :post_imports do
-    post :preview
-    post :validate
-    post '', action: :create
-  end
-
   resources :wiki_pages, path: 'wiki', only: [:index, :show, :create, :update] do
     collection do
       get :search
@@ -58,6 +52,8 @@ Rails.application.routes.draw do
 
   resources :posts, only: [:index, :show, :create, :update] do
     collection do
+      get :metadata
+      post :bulk
       get :random
       get :changes
       get :versions, to: 'post_versions#index'

backend/spec/models/post_spec.rb

@@ -110,7 +110,7 @@ RSpec.describe Post, type: :model do
     end
 
     describe '.resized_thumbnail_attachment' do
-      it 'centre-crops a wide image to 180x180 without distorting it' do
+      it 'fits a wide image within 180x180 without distorting it' do
         blob = image_blob(
             width: 360,
             height: 180,
@@ -123,13 +123,13 @@ RSpec.describe Post, type: :model do
         resized = described_class.resized_thumbnail_attachment(upload_for(blob))
         image = read_image(resized)
 
-        expect(image.dimensions).to eq([180, 180])
-        expect_green(colour_at(image, 0, 90))
-        expect_green(colour_at(image, 90, 90))
-        expect_green(colour_at(image, 179, 90))
+        expect(image.dimensions).to eq([180, 90])
+        expect_red(colour_at(image, 0, 45))
+        expect_green(colour_at(image, 90, 45))
+        expect_red(colour_at(image, 179, 45))
       end
 
-      it 'centre-crops a tall image to 180x180 without distorting it' do
+      it 'fits a tall image within 180x180 without distorting it' do
         blob = image_blob(
             width: 180,
             height: 360,
@@ -142,10 +142,10 @@ RSpec.describe Post, type: :model do
         resized = described_class.resized_thumbnail_attachment(upload_for(blob))
         image = read_image(resized)
 
-        expect(image.dimensions).to eq([180, 180])
-        expect_green(colour_at(image, 90, 0))
-        expect_green(colour_at(image, 90, 90))
-        expect_green(colour_at(image, 90, 179))
+        expect(image.dimensions).to eq([90, 180])
+        expect_red(colour_at(image, 45, 0))
+        expect_green(colour_at(image, 45, 90))
+        expect_red(colour_at(image, 45, 179))
       end
 
       it 'keeps a square image square without distortion' do
@@ -192,7 +192,7 @@ RSpec.describe Post, type: :model do
 
         expect(post.thumbnail).to be_attached
         image = read_image(post.thumbnail)
-        expect(image.dimensions).to eq([180, 180])
+        expect(image.dimensions).to eq([180, 135])
       end
 
       it 'does not attach anything when thumbnail conversion fails' do

backend/spec/requests/post_imports_spec.rb

@@ -1,184 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe 'Post imports API', type: :request do
-  let(:member) { create(:user, :member) }
-
-  before do
-    allow(Preview::UrlSafety).to receive(:validate) do |url|
-      [URI.parse(url), ['8.8.8.8']]
-    end
-    allow(PostMetadataFetcher).to receive(:fetch).and_return(
-      title: 'fetched title',
-      thumbnail_base: nil,
-      tags: ''
-    )
-  end
-
-  describe 'POST /posts/import/preview' do
-    it 'requires a member' do
-      sign_out
-      post '/posts/import/preview', params: { source: 'https://example.com/post' }
-      expect(response).to have_http_status(:unauthorized)
-
-      sign_in_as(create(:user, :guest))
-      post '/posts/import/preview', params: { source: 'https://example.com/post' }
-      expect(response).to have_http_status(:forbidden)
-    end
-
-    it 'parses a URL list and returns preview rows' do
-      sign_in_as(member)
-
-      post '/posts/import/preview', params: {
-        source: " https://example.com/one \r\n\r\nhttps://example.com/two"
-      }
-
-      expect(response).to have_http_status(:ok)
-      expect(json.fetch('rows').map { _1.fetch('source_row') }).to eq([1, 3])
-      expect(json.fetch('rows').map { _1.fetch('url') }).to eq([
-        'https://example.com/one',
-        'https://example.com/two'
-      ])
-    end
-
-    it 'returns a safe 400 response for an invalid source' do
-      sign_in_as(member)
-
-      post '/posts/import/preview', params: { source: '' }
-
-      expect(response).to have_http_status(:bad_request)
-      expect(json.fetch('message')).to eq('URL を入力してください．')
-    end
-  end
-
-  describe 'POST /posts/import/validate' do
-    it 'accepts camel-case row properties and returns their warnings' do
-      sign_in_as(member)
-
-      post '/posts/import/validate', params: {
-        rows: [{
-          sourceRow: '1',
-          url: 'https://example.com/post',
-          metadataUrl: 'https://example.com/post',
-          attributes: { title: 'manual title' },
-          provenance: { url: 'manual', title: 'manual' },
-          tagSources: { automatic: '', manual: '' },
-          fieldWarnings: { title: ['old warning'] },
-          baseWarnings: ['base warning']
-        }],
-        changed_row: -1
-      }
-
-      expect(response).to have_http_status(:ok)
-      result = json.fetch('rows').first
-      expect(result.fetch('source_row')).to eq(1)
-      expect(result.fetch('tag_sources')).to eq('automatic' => '', 'manual' => '')
-      expect(result.fetch('field_warnings')).to eq('title' => ['old warning'])
-      expect(result.fetch('base_warnings')).to eq(['base warning'])
-    end
-
-    it 'rejects a non-array rows value with 400' do
-      sign_in_as(member)
-
-      post '/posts/import/validate', params: { rows: { sourceRow: 1 }, changed_row: -1 }
-
-      expect(response).to have_http_status(:bad_request)
-      expect(json.fetch('message')).to eq('取込行の形式が不正です．')
-    end
-
-    it 'returns original created datetime validation errors for minute precision' do
-      sign_in_as(member)
-
-      post '/posts/import/validate', params: {
-        rows: [{
-          sourceRow: 1,
-          url: 'https://example.com/post',
-          metadataUrl: 'https://example.com/post',
-          attributes: {
-            originalCreatedFrom: '2020-01-01T00:00:30Z',
-            originalCreatedBefore: '2020-01-01T00:01Z' },
-          provenance: {
-            url: 'manual',
-            originalCreatedFrom: 'manual',
-            originalCreatedBefore: 'manual' },
-          tagSources: { automatic: '', manual: '' }
-        }],
-        changed_row: -1
-      }
-
-      expect(response).to have_http_status(:ok)
-      expect(json.fetch('rows').first.fetch('validation_errors')).to include(
-        'original_created_from' => ['オリジナルの作成日時は分単位で入力してください．']
-      )
-      expect(json.fetch('rows').first.fetch('validation_errors'))
-          .not_to have_key('original_created_at')
-    end
-  end
-
-  describe 'POST /posts/import' do
-    it 'keeps the duration string contract through preview, validate, and import' do
-      sign_in_as(member)
-      allow(PostMetadataFetcher).to receive(:fetch).and_return(
-        title: 'fetched title',
-        thumbnail_base: nil,
-        duration: '2.5',
-        tags: '動画'
-      )
-
-      post '/posts/import/preview', params: {
-        source: 'https://example.com/video'
-      }
-      preview_row = json.fetch('rows').first
-      expect(preview_row.dig('attributes', 'duration')).to eq('2.5')
-
-      post '/posts/import/validate', params: {
-        rows: [{
-          sourceRow: preview_row.fetch('source_row'),
-          url: preview_row.fetch('url'),
-          attributes: preview_row.fetch('attributes'),
-          provenance: preview_row.fetch('provenance'),
-          tagSources: preview_row.fetch('tag_sources'),
-          metadataUrl: preview_row.fetch('metadata_url')
-        }],
-        changed_row: -1
-      }
-      validated_row = json.fetch('rows').first
-      expect(validated_row.dig('attributes', 'duration')).to eq('2.5')
-
-      post '/posts/import', params: {
-        rows: [{
-          sourceRow: validated_row.fetch('source_row'),
-          url: validated_row.fetch('url'),
-          attributes: validated_row.fetch('attributes'),
-          provenance: validated_row.fetch('provenance'),
-          tagSources: validated_row.fetch('tag_sources'),
-          metadataUrl: validated_row.fetch('metadata_url')
-        }]
-      }
-
-      expect(response).to have_http_status(:ok)
-      expect(Post.order(:id).last.video_ms).to eq(2_500)
-    end
-
-    it 'returns a formal skipped result for an existing post' do
-      existing = create(:post, url: 'https://example.com/existing')
-      sign_in_as(member)
-
-      post '/posts/import', params: {
-        rows: [{
-          sourceRow: 1,
-          url: existing.url,
-          attributes: { title: 'ignored' },
-          provenance: { url: 'manual', title: 'manual' },
-          tagSources: { automatic: '', manual: '' }
-        }]
-      }
-
-      expect(response).to have_http_status(:ok)
-      expect(json).to include('created' => 0, 'skipped' => 1, 'failed' => 0)
-      expect(json.fetch('rows').first).to include(
-        'status' => 'skipped',
-        'existing_post_id' => existing.id
-      )
-    end
-  end
-end

backend/spec/requests/posts_spec.rb

@@ -9,11 +9,11 @@ RSpec.describe 'Posts API', type: :request do
   # resized_thumbnail! が MiniMagick 依存でコケやすいので request spec ではスタブしとくのが無難。
   before do
     allow_any_instance_of(Post).to receive(:resized_thumbnail!).and_return(true)
-    allow(Post).to receive(:resized_thumbnail_attachment).and_return(
-      io: StringIO.new('dummy'),
-      filename: 'resized_thumbnail.jpg',
-      content_type: 'image/jpeg'
-    )
+    allow(Post).to receive(:resized_thumbnail_attachment) do
+      { io: StringIO.new('dummy'),
+        filename: 'resized_thumbnail.jpg',
+        content_type: 'image/jpeg' }
+    end
   end
 
   def create_nico_tag!(name)
@@ -21,8 +21,7 @@ RSpec.describe 'Posts API', type: :request do
   end
 
   def dummy_upload
-    # 中身は何でもいい（加工処理はスタブしてる）
-    Rack::Test::UploadedFile.new(StringIO.new('dummy'), 'image/jpeg', original_filename: 'dummy.jpg')
+    real_thumbnail_upload
   end
 
   def real_thumbnail_upload
@@ -102,34 +101,34 @@ RSpec.describe 'Posts API', type: :request do
     end
   end
 
-  describe "GET /posts" do
+  describe 'GET /posts' do
     let!(:user) { create_member_user! }
 
-    let!(:tag_name) { TagName.create!(name: "spec_tag") }
+    let!(:tag_name) { TagName.create!(name: 'spec_tag') }
     let!(:tag) { Tag.create!(tag_name:, category: :general) }
     let!(:tag_name2) { TagName.create!(name: 'unko') }
     let!(:tag2) { Tag.create!(tag_name: tag_name2, category: :deerjikist) }
     let!(:alias_tag_name) { TagName.create!(name: 'manko', canonical: tag_name) }
 
     let!(:hit_post) do
-      Post.create!(uploaded_user: user, title: "hello spec world",
+      Post.create!(uploaded_user: user, title: 'hello spec world',
                    url: 'https://example.com/spec2').tap do |p|
         PostTag.create!(post: p, tag:)
       end
     end
 
     let!(:miss_post) do
-      Post.create!(uploaded_user: user, title: "unrelated title",
+      Post.create!(uploaded_user: user, title: 'unrelated title',
                    url: 'https://example.com/spec3').tap do |p|
         PostTag.create!(post: p, tag: tag2)
       end
     end
 
-    it "returns posts with tag name in JSON" do
-      get "/posts"
+    it 'returns posts with tag name in JSON' do
+      get '/posts'
 
       expect(response).to have_http_status(:ok)
-      posts = json.fetch("posts")
+      posts = json.fetch('posts')
 
       # 全postの全tagが name を含むこと
       expect(posts).not_to be_empty
@@ -142,8 +141,8 @@ RSpec.describe 'Posts API', type: :request do
       expect(json['count']).to be_an(Integer)
 
       # spec_tag を含む投稿が存在すること
-      all_tag_names = posts.flat_map { |p| p["tags"].map { |t| t["name"] } }
-      expect(all_tag_names).to include("spec_tag")
+      all_tag_names = posts.flat_map { |p| p['tags'].map { |t| t['name'] } }
+      expect(all_tag_names).to include('spec_tag')
     end
 
     it 'keeps children and sections keys in non-detail tag responses' do
@@ -162,9 +161,9 @@ RSpec.describe 'Posts API', type: :request do
       ])
     end
 
-    context "when q is provided" do
-      it "filters posts by q (hit case)" do
-        get "/posts", params: { tags: "spec_tag" }
+    context 'when q is provided' do
+      it 'filters posts by q (hit case)' do
+        get '/posts', params: { tags: 'spec_tag' }
 
         expect(response).to have_http_status(:ok)
         posts = json.fetch('posts')
@@ -182,8 +181,8 @@ RSpec.describe 'Posts API', type: :request do
         end
       end
 
-      it "filters posts by q (hit case by alias)" do
-        get "/posts", params: { tags: "manko" }
+      it 'filters posts by q (hit case by alias)' do
+        get '/posts', params: { tags: 'manko' }
 
         expect(response).to have_http_status(:ok)
         posts = json.fetch('posts')
@@ -201,11 +200,11 @@ RSpec.describe 'Posts API', type: :request do
         end
       end
 
-      it "returns empty posts when nothing matches" do
-        get "/posts", params: { tags: "no_such_keyword_12345" }
+      it 'returns empty posts when nothing matches' do
+        get '/posts', params: { tags: 'no_such_keyword_12345' }
 
         expect(response).to have_http_status(:ok)
-        expect(json.fetch("posts")).to eq([])
+        expect(json.fetch('posts')).to eq([])
         expect(json.fetch('count')).to eq(0)
       end
     end
@@ -693,6 +692,73 @@ RSpec.describe 'Posts API', type: :request do
     end
   end
 
+  describe 'GET /posts/metadata' do
+    let(:member) { create(:user, :member) }
+
+    it 'returns compact existing post data without fetching external metadata' do
+      sign_in_as(member)
+      existing = create(
+          :post,
+          title: 'existing post',
+          url: 'https://example.com/existing')
+      existing.thumbnail.attach(
+          io: StringIO.new('thumbnail'),
+          filename: 'thumbnail.jpg',
+          content_type: 'image/jpeg')
+      expect(PostMetadataFetcher).not_to receive(:fetch)
+
+      get '/posts/metadata', params: { url: 'https://example.com/existing' }
+
+      expect(response).to have_http_status(:ok)
+      expect(json).to include(
+          'url' => existing.url,
+          'existing_post_id' => existing.id,
+          'field_warnings' => { })
+      expect(json.fetch('existing_post')).to include(
+          'id' => existing.id,
+          'title' => existing.title,
+          'url' => existing.url,
+          'thumbnail_base' => existing.thumbnail_base)
+      expect(json.dig('existing_post', 'thumbnail'))
+          .to include('/rails/active_storage/blobs/proxy/')
+    end
+
+    it 'returns fetched metadata and structured display tags' do
+      sign_in_as(member)
+      allow(Preview::UrlSafety).to receive(:validate)
+      allow(PostMetadataFetcher).to receive(:fetch).and_return(
+          title: 'fetched title',
+          thumbnail_base: 'https://example.com/thumbnail.jpg',
+          tags: 'character:虹夏',
+          display_tags: [{ name: '虹夏', category: 'character' }],
+          original_created_from: nil,
+          original_created_before: nil,
+          duration: '1:00',
+          video_ms: 60_000)
+
+      get '/posts/metadata', params: { url: 'https://example.com/new' }
+
+      expect(response).to have_http_status(:ok)
+      expect(json).to include(
+          'url' => 'https://example.com/new',
+          'title' => 'fetched title',
+          'duration' => '1:00',
+          'video_ms' => 60_000,
+          'field_warnings' => { })
+      expect(json.fetch('display_tags')).to eq(
+          [{ 'name' => '虹夏', 'category' => 'character' }])
+    end
+
+    it 'returns URL validation errors as 422' do
+      sign_in_as(member)
+
+      get '/posts/metadata', params: { url: 'file:///etc/passwd' }
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(json.fetch('errors')).to have_key('url')
+    end
+  end
+
   describe 'POST /posts' do
     let(:member) { create(:user, :member) }
     let!(:alias_tag_name) { TagName.create!(name: 'manko', canonical: tag_name) }
@@ -712,6 +778,46 @@ RSpec.describe 'Posts API', type: :request do
       expect(response).to have_http_status(:forbidden)
     end
 
+    it 'dry-runs without persisting posts or new tags' do
+      sign_in_as(member)
+      counts = [Post.count, Tag.count, TagName.count]
+
+      post '/posts?dry=1', params: post_write_params(
+          title: 'dry-run post',
+          url: 'https://example.com/dry-run',
+          tags: 'character:new_dry_run_tag')
+
+      expect(response).to have_http_status(:ok)
+      expect(json).to include(
+          'url' => 'https://example.com/dry-run',
+          'tags' => 'new_dry_run_tag',
+          'existing_post_id' => nil)
+      expect(json.fetch('display_tags')).to eq(
+          [{ 'name' => 'new_dry_run_tag',
+             'category' => 'character',
+             'section_literals' => [] }])
+      expect([Post.count, Tag.count, TagName.count]).to eq(counts)
+    end
+
+    it 'dry-runs an existing URL without validating its upload' do
+      sign_in_as(member)
+      existing = create(:post, url: 'https://example.com/dry-existing')
+      invalid_upload = Rack::Test::UploadedFile.new(
+          StringIO.new('<svg></svg>'),
+          'image/png',
+          original_filename: 'thumbnail.png')
+
+      post '/posts?dry=1', params: post_write_params(
+          title: '',
+          url: existing.url,
+          tags: '',
+          thumbnail: invalid_upload)
+
+      expect(response).to have_http_status(:ok)
+      expect(json).to include('existing_post_id' => existing.id)
+      expect(json.fetch('field_warnings')).not_to have_key('thumbnail_base')
+    end
+
     it '201 and creates post + tags when member' do
       sign_in_as(member)
 
@@ -769,7 +875,8 @@ RSpec.describe 'Posts API', type: :request do
       )
 
       expect(response).to have_http_status(:created)
-      expect(open_transactions).to eq([baseline_open_transactions])
+      expect(open_transactions).to eq(
+          [baseline_open_transactions, baseline_open_transactions])
     end
 
     it 'returns 422 and does not create a post when thumbnail resize fails' do
@@ -827,7 +934,7 @@ RSpec.describe 'Posts API', type: :request do
 
       expect(response).to have_http_status(:unprocessable_entity)
       expect(json.fetch('errors')).to include(
-        'tags' => ['廃止済みタグは付与できません．']
+        'tags' => ['廃止済みタグがあります: deprecated_direct_tag']
       )
     end
 
@@ -1054,7 +1161,7 @@ RSpec.describe 'Posts API', type: :request do
       )
     end
 
-    context "when nico tag already exists in tags" do
+    context 'when nico tag already exists in tags' do
       before do
         Tag.find_undiscard_or_create_by!(
             tag_name: TagName.find_undiscard_or_create_by!(name: 'nico:nico_tag'),
@@ -1251,6 +1358,47 @@ RSpec.describe 'Posts API', type: :request do
     end
   end
 
+  describe 'POST /posts/bulk' do
+    let(:member) { create(:user, :member) }
+
+    it 'parses the manifest and indexed thumbnail parts' do
+      sign_in_as(member)
+      manifest = [{ 'url' => 'https://example.com/bulk',
+                    'title' => 'bulk post',
+                    'tags' => 'spec_tag',
+                    'parent_post_ids' => '' }]
+      creator = instance_double(
+          PostBulkCreator,
+          run: { results: [{ status: 'created', post: { id: 123 } }] })
+      allow(PostBulkCreator).to receive(:new).and_return(creator)
+
+      post '/posts/bulk', params: {
+          posts: JSON.generate(manifest),
+          thumbnails: { '0' => real_thumbnail_upload } }
+
+      expect(response).to have_http_status(:ok)
+      expect(json.fetch('results')).to eq(
+          [{ 'status' => 'created', 'post' => { 'id' => 123 } }])
+      expect(PostBulkCreator).to have_received(:new) do |arguments|
+        expect(arguments[:actor]).to eq(member)
+        expect(arguments[:posts]).to eq(manifest)
+        expect(arguments[:thumbnails].keys).to eq([0])
+        expect(arguments[:host]).to eq('http://www.example.com')
+      end
+    end
+
+    it 'rejects malformed manifests as a request-level error' do
+      sign_in_as(member)
+
+      post '/posts/bulk', params: {
+          posts: '{',
+          thumbnails: { '0' => real_thumbnail_upload } }
+
+      expect(response).to have_http_status(:bad_request)
+      expect(json.fetch('message')).to eq('posts manifest の JSON が不正です．')
+    end
+  end
+
   describe 'PUT /posts/:id' do
     let(:member) { create(:user, :member) }
 
@@ -1307,7 +1455,7 @@ RSpec.describe 'Posts API', type: :request do
       )
     end
 
-    context "when nico tag already exists in tags" do
+    context 'when nico tag already exists in tags' do
       before do
         Tag.find_undiscard_or_create_by!(
             tag_name: TagName.find_undiscard_or_create_by!(name: 'nico:nico_tag'),
@@ -1564,7 +1712,7 @@ RSpec.describe 'Posts API', type: :request do
         expect(post_record.reload.title).to eq('updated by other user')
       end
 
-      it 'returns 409 with mergeable true when stale tag changes do not conflict but merge is not requested' do
+      it 'returns mergeable 409 for stale non-conflicting tag changes without merge' do
         sign_in_as(member)
 
         base_version = create_post_version_for!(post_record.reload)
@@ -2271,9 +2419,9 @@ RSpec.describe 'Posts API', type: :request do
 
       expect(response).to have_http_status(:created)
       expect(Time.iso8601(json.fetch('original_created_from')))
-          .to eq(Time.iso8601('2020-01-01T00:00Z'))
+          .to eq(Time.utc(2020, 1, 1, 0, 0))
       expect(Time.iso8601(json.fetch('original_created_before')))
-          .to eq(Time.iso8601('2020-01-01T00:01Z'))
+          .to eq(Time.utc(2020, 1, 1, 0, 1))
     end
 
     it 'rejects unparseable original created timestamps on PUT /posts/:id' do

backend/spec/requests/wiki_body_search_pending_spec.rb

@@ -1,27 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe 'Wiki body search', type: :request do
-  let!(:user) { create_member_user! }
-
-  it 'searches wiki pages by body text' do
-    pending '#336 で対応予定'
-
-    Wiki::Commit.create_content!(
-        tag_name: TagName.create!(name: 'wiki_body_search_hit'),
-        body: 'unique body keyword for wiki search',
-        created_by_user: user,
-        message: 'init')
-
-    Wiki::Commit.create_content!(
-        tag_name: TagName.create!(name: 'wiki_body_search_miss'),
-        body: 'ordinary body',
-        created_by_user: user,
-        message: 'init')
-
-    get '/wiki/search', params: { body: 'unique body keyword' }
-
-    expect(response).to have_http_status(:ok)
-    expect(json.map { |page| page['title'] }).to include('wiki_body_search_hit')
-    expect(json.map { |page| page['title'] }).not_to include('wiki_body_search_miss')
-  end
-end

backend/spec/requests/wiki_restore_pending_spec.rb

@@ -1,37 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe 'Wiki restore', type: :request do
-  let!(:user) { create_member_user! }
-
-  def auth_headers user
-    { 'X-Transfer-Code' => user.inheritance_code }
-  end
-
-  it 'restores wiki page to previous version' do
-    pending '#337 で対応予定'
-
-    page =
-        Wiki::Commit.create_content!(
-            tag_name: TagName.create!(name: 'wiki_restore_page'),
-            body: 'v1',
-            created_by_user: user,
-            message: 'init')
-
-    v1 = page.wiki_versions.order(:version_no).last
-
-    Wiki::Commit.content!(
-        page:,
-        body: 'v2',
-        created_user: user,
-        message: 'edit',
-        base_revision_id: page.current_revision.id)
-
-    post "/wiki/#{ page.id }/restore",
-         params: { version_no: v1.version_no },
-         headers: auth_headers(user)
-
-    expect(response).to have_http_status(:ok)
-    expect(page.reload.body).to eq('v1')
-    expect(page.wiki_versions.order(:version_no).last.event_type).to eq('restore')
-  end
-end

backend/spec/services/post_bulk_creator_spec.rb

@@ -0,0 +1,59 @@
+require 'rails_helper'
+
+RSpec.describe PostBulkCreator do
+  it 'limits workers to two and keeps failures in their request slots' do
+    actor = instance_double(User, id: 123)
+    allow(User).to receive(:find).with(123) {
+      instance_double(User, id: 123)
+    }
+    mutex = Mutex.new
+    active = 0
+    maximum_active = 0
+
+    allow(PostCreatePreflight).to receive(:new) do |attributes:, **|
+      preflight = instance_double(PostCreatePreflight)
+      allow(preflight).to receive(:run) do
+        mutex.synchronize do
+          active += 1
+          maximum_active = [maximum_active, active].max
+        end
+        sleep 0.02
+        mutex.synchronize { active -= 1 }
+        attributes.symbolize_keys.merge(
+            existing_post_id: nil,
+            field_warnings: { },
+            base_warnings: [])
+      end
+      preflight
+    end
+    allow(PostCreator).to receive(:new) do |attributes:, **|
+      creator = instance_double(PostCreator)
+      if attributes[:title] == 'broken'
+        allow(creator).to receive(:create!).and_raise(StandardError, 'broken')
+      else
+        post = instance_double(Post, id: attributes[:title].delete_prefix('post ').to_i)
+        allow(creator).to receive(:create!).and_return(post)
+      end
+      creator
+    end
+    posts = [
+        { 'title' => 'post 1', 'url' => 'https://example.com/1' },
+        { 'title' => 'broken', 'url' => 'https://example.com/2' },
+        { 'title' => 'post 3', 'url' => 'https://example.com/3' },
+        { 'title' => 'post 4', 'url' => 'https://example.com/4' }]
+
+    results = described_class.new(
+        actor:,
+        posts:,
+        thumbnails: { }).run.fetch(:results)
+
+    expect(maximum_active).to eq(2)
+    expect(results.length).to eq(posts.length)
+    expect(results.map { _1[:status] }).to eq(
+        ['created', 'failed', 'created', 'created'])
+    expect(results[0].dig(:post, :id)).to eq(1)
+    expect(results[1]).to include(status: 'failed', recoverable: false)
+    expect(results[2].dig(:post, :id)).to eq(3)
+    expect(results[3].dig(:post, :id)).to eq(4)
+  end
+end

backend/spec/services/post_create_plan_spec.rb

@@ -0,0 +1,82 @@
+require 'rails_helper'
+
+RSpec.describe PostCreatePlan do
+  def create_tag! name, category
+    Tag.create!(name:, category:)
+  end
+
+  before do
+    create_tag!('タグ希望', :meta)
+    create_tag!('ニジラー情報不詳', :meta)
+  end
+
+  it 'plans direct and existing default tags without persisting records' do
+    counts = [TagName.count, Tag.count]
+
+    plan = described_class.new(
+        attributes: {
+            url: 'https://example.com/post',
+            title: 'title',
+            tags: 'character:new_character',
+            parent_post_ids: '' }).build!
+
+    expect(plan[:tags]).to eq('new_character')
+    expect(plan[:direct_tag_specs]).to eq(
+        [{ name: 'new_character', category: :character }])
+    expect(plan[:default_tag_specs]).to include(
+        { name: 'タグ希望', category: :meta },
+        { name: 'ニジラー情報不詳', category: :meta })
+    expect([TagName.count, Tag.count]).to eq(counts)
+  end
+
+  it 'resolves aliases and keeps tag sections separate from canonical names' do
+    canonical = create_tag!('虹夏', :character)
+    TagName.create!(name: 'にじか', canonical: canonical.tag_name)
+    create_tag!('動画', :meta)
+
+    plan = described_class.new(
+        attributes: {
+            url: 'https://example.com/video',
+            title: 'video',
+            tags: '動画 にじか[0:10-0:20]',
+            duration: '1:00',
+            parent_post_ids: '' }).build!
+
+    expect(plan[:tags].split).to include('動画', '虹夏[0:10-0:20]')
+    expect(plan[:display_tags]).to include(
+        { name: '虹夏',
+          category: 'character',
+          section_literals: ['[0:10-0:20]'] })
+    expect(plan[:video_ms]).to eq(60_000)
+  end
+
+  it 'validates a new tag name without persisting it' do
+    long_name = 'a' * 256
+    counts = [TagName.count, Tag.count]
+
+    expect {
+      described_class.new(
+          attributes: {
+              url: 'https://example.com/post',
+              title: 'title',
+              tags: long_name,
+              parent_post_ids: '' }).build!
+    }.to raise_error(ActiveRecord::RecordInvalid) { |error|
+      expect(error.record.errors[:tags]).not_to be_empty
+    }
+    expect([TagName.count, Tag.count]).to eq(counts)
+  end
+
+  it 'ignores duration when the planned tags do not include video' do
+    plan = described_class.new(
+        attributes: {
+            url: 'https://example.com/post',
+            title: 'title',
+            tags: 'ordinary_tag',
+            duration: 'invalid',
+            parent_post_ids: '' }).build!
+
+    expect(plan[:duration]).to eq('invalid')
+    expect(plan[:video_ms]).to be_nil
+  end
+end

backend/spec/services/post_creator_spec.rb

@@ -20,12 +20,12 @@ RSpec.describe PostCreator do
     allow(PostVersionRecorder).to receive(:record!)
   end
 
-  it 'prefers an explicit upload over thumbnail_base' do
-    allow(Post).to receive(:resized_thumbnail_attachment).and_return(
-        io: StringIO.new('upload'),
+  it 'prefers thumbnail_base over an explicit upload' do
+    expect(Post).not_to receive(:resized_thumbnail_attachment)
+    allow(Post).to receive(:remote_thumbnail_attachment).and_return(
+        io: StringIO.new('remote'),
         filename: 'resized_thumbnail.jpg',
         content_type: 'image/jpeg')
-    expect_any_instance_of(Post).not_to receive(:attach_thumbnail_from_url!)
 
     post = described_class.new(
         actor:,
@@ -41,13 +41,12 @@ RSpec.describe PostCreator do
   end
 
   it 'uses the common remote thumbnail attach path when thumbnail_base is given' do
-    expect_any_instance_of(Post).to receive(:attach_thumbnail_from_url!)
-        .with('https://example.com/thumb.jpg') do |post, _url|
-      post.thumbnail.attach(
-          io: StringIO.new('thumbnail'),
-          filename: 'thumbnail.jpg',
-          content_type: 'image/jpeg')
-    end
+    expect(Post).to receive(:remote_thumbnail_attachment)
+        .with('https://example.com/thumb.jpg')
+        .and_return(
+            io: StringIO.new('thumbnail'),
+            filename: 'thumbnail.jpg',
+            content_type: 'image/jpeg')
 
     post = described_class.new(
         actor:,
@@ -61,8 +60,8 @@ RSpec.describe PostCreator do
     expect(post.thumbnail).to be_attached
   end
 
-  it 'keeps creating the post and records a warning when remote thumbnail fetch fails' do
-    allow_any_instance_of(Post).to receive(:attach_thumbnail_from_url!)
+  it 'does not create a post when remote thumbnail fetch fails' do
+    allow(Post).to receive(:remote_thumbnail_attachment)
         .and_raise(Post::RemoteThumbnailFetchFailed, 'サムネール画像を取得できませんでした．')
     creator = described_class.new(
         actor:,
@@ -72,11 +71,8 @@ RSpec.describe PostCreator do
           thumbnail_base: 'https://example.com/thumb.jpg',
           tags: '' })
 
-    post = creator.create!
-
-    expect(post.thumbnail_base).to eq('https://example.com/thumb.jpg')
-    expect(post.thumbnail).not_to be_attached
-    expect(creator.field_warnings).to eq(
-        thumbnail_base: ['サムネール画像を取得できませんでした．'])
+    post_count = Post.count
+    expect { creator.create! }.to raise_error(Post::RemoteThumbnailFetchFailed)
+    expect(Post.count).to eq(post_count)
   end
 end

backend/spec/services/post_import_row_normaliser_spec.rb

@@ -1,77 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe PostImportRowNormaliser do
-  def valid_row(overrides = { })
-    {
-      sourceRow: '1',
-      url: 'https://example.com/post',
-      metadataUrl: 'https://example.com/post',
-      attributes: { title: 'title', duration: '1' },
-      provenance: { url: 'manual', title: 'automatic' },
-      tagSources: { automatic: 'tag', manual: '' }
-    }.deep_merge(overrides)
-  end
-
-  describe '.normalise!' do
-    it 'normalises aliases and source rows into a permitted plain hash' do
-      row = ActionController::Parameters.new(valid_row)
-
-      expect(described_class.normalise!([row])).to eq([
-        {
-          'source_row' => 1,
-          'url' => 'https://example.com/post',
-          'metadata_url' => 'https://example.com/post',
-          'attributes' => { 'title' => 'title', 'duration' => '1' },
-          'provenance' => { 'url' => 'manual', 'title' => 'automatic' },
-          'tag_sources' => { 'automatic' => 'tag', 'manual' => '' }
-        }
-      ])
-    end
-
-    it 'normalises source rows before checking duplicates' do
-      rows = [valid_row, valid_row(sourceRow: 1, url: 'https://example.com/other')]
-
-      expect { described_class.normalise!(rows) }
-          .to raise_error(ArgumentError, '元行番号が重複しています．')
-    end
-
-    it 'rejects non-array batches and non-hash rows' do
-      expect { described_class.normalise!({}) }
-          .to raise_error(ArgumentError, '取込行の形式が不正です．')
-      expect { described_class.normalise!(['row']) }
-          .to raise_error(ArgumentError, '取込行の形式が不正です．')
-    end
-
-    it 'rejects unknown attributes and invalid field types' do
-      expect { described_class.normalise!([valid_row(attributes: { unknown: 'x' })]) }
-          .to raise_error(ArgumentError, '取込項目が不正です．')
-      expect { described_class.normalise!([valid_row(attributes: { title: [] })]) }
-          .to raise_error(ArgumentError, '取込項目の型が不正です．')
-      expect { described_class.normalise!([valid_row(attributes: { duration: false })]) }
-          .to raise_error(ArgumentError, '取込項目の型が不正です．')
-    end
-
-    it 'rejects unknown provenance and tag-source values' do
-      expect { described_class.normalise!([valid_row(provenance: { title: 'mapped' })]) }
-          .to raise_error(ArgumentError, '値の由来が不正です．')
-      expect { described_class.normalise!([valid_row(tagSources: { mapped: 'tag' })]) }
-          .to raise_error(ArgumentError, 'タグ由来の形式が不正です．')
-    end
-
-    it 'accepts warning fields only at the validation boundary' do
-      row = valid_row.merge(
-        fieldWarnings: { title: ['取得できませんでした．'] },
-        baseWarnings: ['確認してください．']
-      )
-
-      without_warnings = described_class.normalise!([row]).first
-      with_warnings = described_class.normalise!([row], allow_warning_fields: true).first
-
-      expect(without_warnings).not_to include('field_warnings', 'base_warnings')
-      expect(with_warnings).to include(
-        'field_warnings' => { 'title' => ['取得できませんでした．'] },
-        'base_warnings' => ['確認してください．']
-      )
-    end
-  end
-end

backend/spec/services/post_import_runner_spec.rb

@@ -1,152 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe PostImportRunner do
-  let(:actor) { create(:user, :member) }
-
-  def row(source_row: 1, url: 'https://example.com/post')
-    {
-      sourceRow: source_row,
-      url:,
-      attributes: { title: 'title', tags: '' },
-      provenance: { url: 'manual', title: 'manual', tags: 'manual' },
-      tagSources: { automatic: '', manual: '' }
-    }
-  end
-
-  def preview(source_row: 1, errors: { }, skip_reason: nil, existing_post_id: nil)
-    {
-      source_row:,
-      attributes: { 'title' => 'title', 'tags' => '' },
-      validation_errors: errors,
-      skip_reason:,
-      existing_post_id:
-    }
-  end
-
-  it 'previews the whole batch once before processing individual rows' do
-    rows = [row, row(source_row: 2, url: 'https://example.com/two')]
-    previewer = instance_double(PostImportPreviewer)
-    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
-    expect(previewer).to receive(:preview_rows)
-        .with(
-          rows: satisfy { _1.map { |row_value| row_value['source_row'] } == [1, 2] },
-          fetch_metadata: false
-        )
-        .and_return([preview, preview(source_row: 2)])
-    allow(PostCreator).to receive(:new).and_return(
-      instance_double(PostCreator, create!: create(:post))
-    )
-
-    result = described_class.new(actor:, rows:).run
-
-    expect(result).to include(created: 2, skipped: 0, failed: 0)
-  end
-
-  it 'treats validation errors as failures before an existing skip' do
-    existing = create(:post)
-    previewer = instance_double(PostImportPreviewer)
-    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
-    allow(previewer).to receive(:preview_rows).and_return([
-      preview(errors: { url: ['URL が重複しています．'] },
-              skip_reason: 'existing', existing_post_id: existing.id)
-    ])
-    expect(PostCreator).not_to receive(:new)
-
-    result = described_class.new(actor:, rows: [row]).run.fetch(:rows).first
-
-    expect(result).to include(
-      status: 'failed',
-      errors: { url: ['URL が重複しています．'] },
-      recoverable: true
-    )
-  end
-
-  it 'returns the existing post ID for skipped rows' do
-    existing = create(:post)
-    previewer = instance_double(PostImportPreviewer)
-    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
-    allow(previewer).to receive(:preview_rows).and_return([
-      preview(skip_reason: 'existing', existing_post_id: existing.id)
-    ])
-
-    result = described_class.new(actor:, rows: [row]).run.fetch(:rows).first
-
-    expect(result).to eq(
-      source_row: 1,
-      status: 'skipped',
-      existing_post_id: existing.id
-    )
-  end
-
-  it 'converts a URL uniqueness validation race into a skip' do
-    existing = create(:post, url: 'https://example.com/race')
-    invalid = Post.new(url: existing.url)
-    invalid.errors.add(:url, :taken)
-    previewer = instance_double(PostImportPreviewer)
-    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
-    allow(previewer).to receive(:preview_rows).and_return([preview])
-    creator = instance_double(PostCreator)
-    allow(PostCreator).to receive(:new).and_return(creator)
-    allow(creator).to receive(:create!).and_raise(ActiveRecord::RecordInvalid.new(invalid))
-
-    result = described_class.new(
-      actor:,
-      rows: [row(url: 'https://EXAMPLE.com/race/')]
-    ).run.fetch(:rows).first
-
-    expect(result).to include(status: 'skipped', existing_post_id: existing.id)
-  end
-
-  it 're-raises RecordNotUnique errors unrelated to the posts URL index' do
-    previewer = instance_double(PostImportPreviewer)
-    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
-    allow(previewer).to receive(:preview_rows).and_return([preview])
-    creator = instance_double(PostCreator)
-    allow(PostCreator).to receive(:new).and_return(creator)
-    allow(creator).to receive(:create!)
-        .and_raise(ActiveRecord::RecordNotUnique, 'other_unique_index')
-
-    expect {
-      described_class.new(actor:, rows: [row]).run
-    }.to raise_error(ActiveRecord::RecordNotUnique)
-  end
-
-  it 'converts a posts URL index race into a skip' do
-    existing = create(:post, url: 'https://example.com/index-race')
-    previewer = instance_double(PostImportPreviewer)
-    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
-    allow(previewer).to receive(:preview_rows).and_return([preview])
-    creator = instance_double(PostCreator)
-    allow(PostCreator).to receive(:new).and_return(creator)
-    allow(creator).to receive(:create!).and_raise(
-      ActiveRecord::RecordNotUnique,
-      'duplicate key index_posts_on_url'
-    )
-
-    result = described_class.new(
-      actor:,
-      rows: [row(url: 'https://EXAMPLE.com/index-race/')]
-    ).run.fetch(:rows).first
-
-    expect(result).to include(status: 'skipped', existing_post_id: existing.id)
-  end
-
-  it 'returns thumbnail warnings from PostCreator on a created row' do
-    previewer = instance_double(PostImportPreviewer)
-    allow(PostImportPreviewer).to receive(:new).and_return(previewer)
-    allow(previewer).to receive(:preview_rows).and_return([preview])
-    created_post = create(:post)
-    creator = instance_double(
-        PostCreator,
-        create!: created_post,
-        field_warnings: { thumbnail_base: ['サムネール画像を取得できませんでした．'] })
-    allow(PostCreator).to receive(:new).and_return(creator)
-
-    result = described_class.new(actor:, rows: [row]).run.fetch(:rows).first
-
-    expect(result).to include(
-      status: 'created',
-      field_warnings: { thumbnail_base: ['サムネール画像を取得できませんでした．'] }
-    )
-  end
-end

backend/spec/services/post_import_url_list_parser_spec.rb

@@ -1,40 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe PostImportUrlListParser do
-  describe '.parse' do
-    it 'trims URLs, ignores blank lines, and preserves source line numbers' do
-      source = "  https://example.com/one  \r\n\r\nhttps://example.com/two\n"
-
-      expect(described_class.parse(source)).to eq([
-        { source_row: 1, url: 'https://example.com/one' },
-        { source_row: 3, url: 'https://example.com/two' }
-      ])
-    end
-
-    it 'rejects an empty URL list' do
-      expect { described_class.parse(" \n\r\n") }
-          .to raise_error(ArgumentError, 'URL を入力してください．')
-    end
-
-    it 'rejects more than 100 non-empty rows' do
-      source = 101.times.map { |index| "https://example.com/#{ index }" }.join("\n")
-
-      expect { described_class.parse(source) }
-          .to raise_error(ArgumentError, '取込件数は 100 件までです．')
-    end
-
-    it 'includes the original line number in an oversized URL error' do
-      source = "\n#{ 'a' * (described_class::MAX_URL_BYTES + 1) }"
-
-      expect { described_class.parse(source) }
-          .to raise_error(ArgumentError, '2 行目: URL が長すぎます．')
-    end
-
-    it 'rejects an oversized request before parsing rows' do
-      source = 'a' * (described_class::MAX_BYTES + 1)
-
-      expect { described_class.parse(source) }
-          .to raise_error(ArgumentError, '入力が大きすぎます．')
-    end
-  end
-end

backend/spec/services/post_thumbnail_upload_validator_spec.rb

@@ -0,0 +1,52 @@
+require 'rails_helper'
+require 'base64'
+require 'tempfile'
+
+RSpec.describe PostThumbnailUploadValidator do
+  def with_upload bytes, content_type:, filename:
+    tempfile = Tempfile.new(['thumbnail-upload', File.extname(filename)])
+    tempfile.binmode
+    tempfile.write(bytes)
+    tempfile.rewind
+    upload = ActionDispatch::Http::UploadedFile.new(
+        tempfile:,
+        filename:,
+        type: content_type)
+    yield upload
+  ensure
+    tempfile&.close!
+  end
+
+  it 'accepts a raster upload after decoding and rewinds it' do
+    gif = Base64.decode64('R0lGODdhAQABAIABAP///wAAACwAAAAAAQABAAACAkQBADs=')
+
+    with_upload(gif, content_type: 'image/gif', filename: 'thumbnail.gif') do |upload|
+      expect { described_class.validate!(upload) }.not_to raise_error
+      expect(upload.read(6)).to eq('GIF87a')
+    end
+  end
+
+  it 'rejects SVG content disguised as a raster MIME type' do
+    with_upload(
+        '<svg width="10" height="10"></svg>',
+        content_type: 'image/png',
+        filename: 'thumbnail.png') do |upload|
+      expect { described_class.validate!(upload) }
+          .to raise_error(
+              described_class::InvalidUpload,
+              'サムネイル画像の形式が不正です．')
+    end
+  end
+
+  it 'rejects non-raster content disguised as an image' do
+    with_upload(
+        '%PDF-1.7',
+        content_type: 'image/png',
+        filename: 'thumbnail.png') do |upload|
+      expect { described_class.validate!(upload) }
+          .to raise_error(
+              described_class::InvalidUpload,
+              'サムネイル画像の形式が不正です．')
+    end
+  end
+end

backend/spec/services/preview/thumbnail_fetcher_spec.rb

@@ -2,7 +2,7 @@ require 'rails_helper'
 
 RSpec.describe Preview::ThumbnailFetcher do
   describe '.fetch' do
-    it 'rejects svg thumbnails' do
+    it 'accepts svg thumbnails for the common safe rasterisation path' do
       page = Preview::HttpFetcher::Response.new(
           '<meta property="og:image" content="https://example.com/thumb.svg">',
           'text/html',
@@ -12,8 +12,9 @@ RSpec.describe Preview::ThumbnailFetcher do
           'image/svg+xml',
           'https://example.com/thumb.svg')
 
-      allow(Preview::UrlSafety).to receive(:validate)
-          .and_return([URI.parse('https://example.com/page'), ['203.0.113.10']])
+      allow(Preview::UrlSafety).to receive(:validate) do |url|
+        [URI.parse(url), ['203.0.113.10']]
+      end
       allow(Preview::HttpFetcher).to receive(:fetch)
           .with('https://example.com/page', max_bytes: described_class::HTML_MAX_BYTES)
           .and_return(page)
@@ -21,9 +22,7 @@ RSpec.describe Preview::ThumbnailFetcher do
           .with('https://example.com/thumb.svg')
           .and_return(svg)
 
-      expect {
-        described_class.fetch('https://example.com/page')
-      }.to raise_error(Preview::ThumbnailFetcher::GenerationFailed)
+      expect(described_class.fetch('https://example.com/page')).to eq('<svg></svg>')
     end
 
     it 'accepts allowed image content type with parameters' do
@@ -32,12 +31,13 @@ RSpec.describe Preview::ThumbnailFetcher do
           'text/html',
           'https://example.com/page')
       image = Preview::HttpFetcher::Response.new(
-          'jpeg-bytes',
+          "\xFF\xD8\xFFjpeg-bytes".b,
           'image/jpeg; charset=binary',
           'https://example.com/thumb.jpg')
 
-      allow(Preview::UrlSafety).to receive(:validate)
-          .and_return([URI.parse('https://example.com/page'), ['203.0.113.10']])
+      allow(Preview::UrlSafety).to receive(:validate) do |url|
+        [URI.parse(url), ['203.0.113.10']]
+      end
       allow(Preview::HttpFetcher).to receive(:fetch)
           .with('https://example.com/page', max_bytes: described_class::HTML_MAX_BYTES)
           .and_return(page)
@@ -45,7 +45,8 @@ RSpec.describe Preview::ThumbnailFetcher do
           .with('https://example.com/thumb.jpg')
           .and_return(image)
 
-      expect(described_class.fetch('https://example.com/page')).to eq('jpeg-bytes')
+      expect(described_class.fetch('https://example.com/page'))
+          .to eq("\xFF\xD8\xFFjpeg-bytes".b)
     end
   end
 

backend/spec/tasks/nico_sync_spec.rb

@@ -1,10 +1,10 @@
-require "rails_helper"
+require 'rails_helper'
 
 
-RSpec.describe "nico:sync" do
+RSpec.describe 'nico:sync' do
   def stub_python(json_array)
     status = instance_double(Process::Status, success?: true)
-    allow(Open3).to receive(:capture3).and_return([json_array.to_json, "", status])
+    allow(Open3).to receive(:capture3).and_return([json_array.to_json, '', status])
   end
 
   def create_tag!(name, category:)
@@ -16,21 +16,21 @@ RSpec.describe "nico:sync" do
     NicoTagRelation.create!(nico_tag_id: nico_tag.id, tag_id: tag.id)
   end
 
-  it "既存 post を見つけて、nico tag と linked tag を追加し、差分が出たら bot を付ける" do
+  it '既存 post を見つけて、nico tag と linked tag を追加し、差分が出たら bot を付ける' do
     # 既存 post（正規表現で拾われるURL）
     post = Post.create!(
-      title: "old",
-      url: "https://www.nicovideo.jp/watch/sm9",
+      title: 'old',
+      url: 'https://www.nicovideo.jp/watch/sm9',
       uploaded_user: nil
     )
 
     # 既存の非nicoタグ（kept_non_nico_ids）
-    kept_general = create_tag!("spec_kept", category: "general")
+    kept_general = create_tag!('spec_kept', category: 'general')
     PostTag.create!(post: post, tag: kept_general)
 
     # 追加される linked tag を準備（nico tag に紐付く一般タグ）
-    linked = create_tag!("spec_linked", category: "general")
-    nico = create_tag!("nico:AAA", category: "nico")
+    linked = create_tag!('spec_linked', category: 'general')
+    nico = create_tag!('nico:AAA', category: 'nico')
     link_nico_to_tag!(nico, linked)
 
     # bot / tagme は task 内で使うので作っておく（Tag.bot/tagme がある前提）
@@ -46,22 +46,22 @@ RSpec.describe "nico:sync" do
         'deleted_at' => '2026-01-31 00:00:00' }])
 
     # 外部HTTPは今回「既存 post なので呼ばれない」はずだが、念のため塞ぐ
-    allow(URI).to receive(:open).and_return(StringIO.new("<html></html>"))
+    allow(URI).to receive(:open).and_return(StringIO.new('<html></html>'))
 
-    run_rake_task("nico:sync")
+    run_rake_task('nico:sync')
 
     post.reload
-    active_tag_names = post.tags.joins(:tag_name).pluck("tag_names.name")
+    active_tag_names = post.tags.joins(:tag_name).pluck('tag_names.name')
 
-    expect(active_tag_names).to include("spec_kept")
-    expect(active_tag_names).to include("nico:AAA")
-    expect(active_tag_names).to include("spec_linked")
+    expect(active_tag_names).to include('spec_kept')
+    expect(active_tag_names).to include('nico:AAA')
+    expect(active_tag_names).to include('spec_linked')
 
     expect(post.original_created_from).to eq(Time.iso8601('2026-01-01T03:34:00Z'))
     expect(post.original_created_before).to eq(Time.iso8601('2026-01-01T03:35:00Z'))
 
     # 差分が出るので bot が付く（kept_non_nico_ids != desired_non_nico_ids）
-    expect(active_tag_names).to include("bot操作")
+    expect(active_tag_names).to include('bot操作')
   end
 
   it '既存 post のサムネール取得に共通 attach 経路を使ふ' do
@@ -73,11 +73,11 @@ RSpec.describe "nico:sync" do
     Tag.tagme
 
     stub_python([{ 'code' => 'sm9', 'title' => 't', 'tags' => [] }])
-    allow(URI).to receive(:open)
-        .and_return(
-            StringIO.new(
-                '<meta name="thumbnail" content="https://example.com/thumb.jpg">'))
-    expect(post).to receive(:attach_thumbnail_from_url!)
+    allow(URI).to receive(:open) do
+      StringIO.new(
+          '<meta name="thumbnail" content="https://example.com/thumb.jpg">')
+    end
+    expect_any_instance_of(Post).to receive(:attach_thumbnail_from_url!)
         .with('https://example.com/thumb.jpg')
 
     run_rake_task('nico:sync')
@@ -92,43 +92,45 @@ RSpec.describe "nico:sync" do
     Tag.tagme
 
     stub_python([{ 'code' => 'sm9', 'title' => 't', 'tags' => [] }])
-    allow(URI).to receive(:open)
-        .and_return(
-            StringIO.new(
-                '<meta name="thumbnail" content="https://example.com/thumb.jpg">'))
-    expect(post).to receive(:attach_thumbnail_from_url!)
-        .with('https://example.com/thumb.jpg')
-        .twice
-        .and_raise(Post::RemoteThumbnailFetchFailed, 'failed')
+    allow(URI).to receive(:open) do
+      StringIO.new(
+          '<meta name="thumbnail" content="https://example.com/thumb.jpg">')
+    end
+    calls = 0
+    allow_any_instance_of(Post).to receive(:attach_thumbnail_from_url!) do
+      calls += 1
+      raise Post::RemoteThumbnailFetchFailed, 'failed'
+    end
 
     2.times do
       run_rake_task('nico:sync')
     end
+    expect(calls).to eq(2)
   end
 
-  it "既存 post にあった古い nico tag は active から外され、履歴として discard される" do
+  it '既存 post にあった古い nico tag は active から外され、履歴として discard される' do
     post = Post.create!(
-      title: "old",
-      url: "https://www.nicovideo.jp/watch/sm9",
+      title: 'old',
+      url: 'https://www.nicovideo.jp/watch/sm9',
       uploaded_user: nil
     )
 
     # 旧nicoタグ（今回の同期結果に含まれない）
-    old_nico = create_tag!("nico:OLD", category: "nico")
+    old_nico = create_tag!('nico:OLD', category: 'nico')
     old_pt = PostTag.create!(post: post, tag: old_nico)
     expect(old_pt.discarded_at).to be_nil
 
     # 今回は NEW のみ欲しい
-    new_nico = create_tag!("nico:NEW", category: "nico")
+    new_nico = create_tag!('nico:NEW', category: 'nico')
 
     # bot/tagme 念のため
     Tag.bot
     Tag.tagme
 
-    stub_python([{ "code" => "sm9", "title" => "t", "tags" => ["NEW"] }])
-    allow(URI).to receive(:open).and_return(StringIO.new("<html></html>"))
+    stub_python([{ 'code' => 'sm9', 'title' => 't', 'tags' => ['NEW'] }])
+    allow(URI).to receive(:open).and_return(StringIO.new('<html></html>'))
 
-    run_rake_task("nico:sync")
+    run_rake_task('nico:sync')
 
     # OLD は active から外れる（discarded_at が入る）
     old_pts = PostTag.where(post_id: post.id, tag_id: old_nico.id).order(:id).to_a
@@ -136,9 +138,9 @@ RSpec.describe "nico:sync" do
 
     # NEW は active にいる
     post.reload
-    active_names = post.tags.joins(:tag_name).pluck("tag_names.name")
-    expect(active_names).to include("nico:NEW")
-    expect(active_names).not_to include("nico:OLD")
+    active_names = post.tags.joins(:tag_name).pluck('tag_names.name')
+    expect(active_names).to include('nico:NEW')
+    expect(active_names).not_to include('nico:OLD')
   end
 
   def snapshot_tags(post)

frontend/AGENTS.md

@@ -130,6 +130,13 @@ pass or the remaining failure is clearly blocked.
 
 - Tailwind scans `src/**/*.{html,js,ts,jsx,tsx,mdx}`.
 - Use `cn` from `src/lib/utils.ts` for conditional class names and class merging.
+- In JavaScript, JSX, TypeScript, and TSX, use `cn` from `@/lib/utils`
+  whenever `className` combines multiple values, conditional classes, or a
+  caller-provided `className` prop.
+- Do not construct `className` with template literals, `${ ... }`, string
+  concatenation, arrays joined with spaces, or feature-local class-merging
+  helpers.
+- A static `className="..."` containing only fixed classes does not need `cn`.
 - Reuse components from `src/components/common`, `src/components/layout`, and
   `src/components/ui` before adding new primitives.
 - Keep Tailwind classes consistent with nearby components.
@@ -140,6 +147,15 @@ pass or the remaining failure is clearly blocked.
   short Japanese labels that fit the control.
 - Preserve existing Japanese tone and orthography in nearby UI text, including
   old-kana wording where the file already uses it.
+- Do not add user-facing copy, helper text, descriptions, notes, tooltips,
+  placeholders, empty-state messages, loading messages, or explanatory text
+  unless the user explicitly specified the wording.
+- When new user-facing wording appears necessary, ask the user for the exact
+  wording and placement before implementing it.
+- Do not invent replacement copy when removing unrequested wording.
+- Do not use `タグなし` as user-facing copy for an empty tag state. When the
+  tag state is empty, show no copy. If actual data contains the tag name
+  `タグなし`, treat it as ordinary data and display it normally.
 - When adding dynamic tag colour classes, update `tailwind.config.js` safelist
   if the class cannot be statically detected.
 - Do not introduce new UI libraries or production dependencies without approval.
@@ -586,6 +602,12 @@ offsets, or footer offsets, inspect existing layout components such as
 Do not create a second layout shell before checking whether the current layout
 can be reused or minimally extended.
 
+- Frontend のスマホ／PC表示境界は原則 `md` とする。
+- button stack、footer action、dialogue action は `md` 未満で縦並び、
+  `md` 以上で横並びとする。
+- 同じ画面内で `sm` と `md` を混在させて中間 layout を作らない。
+- 明確に別の responsive 要件がある component だけを例外とする。
+
 ### Delimiter decision table
 
 Use this table before accepting any edited TypeScript or TSX hunk. The table is

frontend/src/App.tsx

@@ -1,8 +1,9 @@
 import { AnimatePresence, LayoutGroup, MotionConfig, motion } from 'framer-motion'
 import { Fragment, useEffect, useMemo, useState } from 'react'
-import { BrowserRouter,
+import { createBrowserRouter,
 	 Navigate,
 	 Route,
+	 RouterProvider,
 	 Routes,
 	 useLocation } from 'react-router-dom'
 
@@ -41,11 +42,8 @@ import NotFound from '@/pages/NotFound'
 import TOSPage from '@/pages/TOSPage.mdx'
 import PostDetailPage from '@/pages/posts/PostDetailPage'
 import PostHistoryPage from '@/pages/posts/PostHistoryPage'
-import PostImportResultPage from '@/pages/posts/PostImportResultPage'
-import PostImportReviewPage from '@/pages/posts/PostImportReviewPage'
-import PostImportSourcePage from '@/pages/posts/PostImportSourcePage'
-import PostListPage from '@/pages/posts/PostListPage'
 import PostNewPage from '@/pages/posts/PostNewPage'
+import PostListPage from '@/pages/posts/PostListPage'
 import PostSearchPage from '@/pages/posts/PostSearchPage'
 import ServiceUnavailable from '@/pages/ServiceUnavailable'
 import SettingPage from '@/pages/users/SettingPage'
@@ -78,9 +76,6 @@ const RouteTransitionWrapper = ({ animationMode, user, setUser }: {
 	    <Route path="/" element={<Navigate to="/posts" replace/>}/>
 	    <Route path="/posts" element={<PostListPage/>}/>
 	    <Route path="/posts/new" element={<PostNewPage user={user}/>}/>
-	    <Route path="/posts/import" element={<PostImportSourcePage user={user}/>}/>
-	    <Route path="/posts/import/:sessionId/review" element={<PostImportReviewPage user={user}/>}/>
-	    <Route path="/posts/import/:sessionId/result" element={<PostImportResultPage user={user}/>}/>
 	    <Route path="/posts/search" element={<PostSearchPage/>}/>
 	    <Route path="/posts/:id" element={<PostDetailRoute user={user}/>}/>
 	    <Route path="/posts/changes" element={<PostHistoryPage/>}/>
@@ -119,9 +114,6 @@ const RouteTransitionWrapper = ({ animationMode, user, setUser }: {
 	  <Route path="/" element={<Navigate to="/posts" replace/>}/>
 	  <Route path="/posts" element={<PostListPage/>}/>
 	  <Route path="/posts/new" element={<PostNewPage user={user}/>}/>
-	  <Route path="/posts/import" element={<PostImportSourcePage user={user}/>}/>
-	  <Route path="/posts/import/:sessionId/review" element={<PostImportReviewPage user={user}/>}/>
-	  <Route path="/posts/import/:sessionId/result" element={<PostImportResultPage user={user}/>}/>
 	  <Route path="/posts/search" element={<PostSearchPage/>}/>
 	  <Route path="/posts/:id" element={<PostDetailRoute user={user}/>}/>
 	  <Route path="/posts/changes" element={<PostHistoryPage/>}/>
@@ -163,7 +155,7 @@ const PostDetailRoute = ({ user }: { user: User | null }) => {
 }
 
 
-const App: FC = () => {
+const RoutedApp: FC = () => {
   const [user, setUser] = useState<User | null> (null)
   const [status, setStatus] = useState (200)
   const behaviourSettings = useClientBehaviourSettings ()
@@ -262,42 +254,46 @@ const App: FC = () => {
   }
 
   return (
-      <>
-	<RouteBlockerOverlay/>
-	{import.meta.env.DEV && <DevModeWatermark/>}
+      <DialogueProvider>
+	<UnsavedChangesGuardProvider>
+	  <KeyboardShortcutsProvider>
+	  <MotionConfig
+	      reducedMotion={
+		  animationMode === 'normal'
+		  ? 'never'
+		  : animationMode === 'reduced'
+		    ? 'user'
+		    : 'always'
+	      }>
+	    <LayoutWrapper>
+	      <motion.div
+		  layout={animationMode === 'off' ? false : 'position'}
+		  transition={{ layout: appLayoutTransition }}
+		  className="relative flex h-dvh w-full flex-col overflow-y-hidden">
+		<TopNav user={user}/>
+		<RouteTransitionWrapper
+		    animationMode={animationMode}
+		    user={user}
+		    setUser={setUser}/>
+	      </motion.div>
+	    </LayoutWrapper>
+	  </MotionConfig>
 
-	<BrowserRouter>
-	  <DialogueProvider>
-	    <UnsavedChangesGuardProvider>
-	      <KeyboardShortcutsProvider>
-	      <MotionConfig
-		  reducedMotion={
-		      animationMode === 'normal'
-		      ? 'never'
-		      : animationMode === 'reduced'
-			? 'user'
-			: 'always'
-		  }>
-		<LayoutWrapper>
-		  <motion.div
-		      layout={animationMode === 'off' ? false : 'position'}
-		      transition={{ layout: appLayoutTransition }}
-		      className="relative flex flex-col h-dvh w-full overflow-y-hidden">
-		    <TopNav user={user}/>
-		    <RouteTransitionWrapper
-			animationMode={animationMode}
-			user={user}
-			setUser={setUser}/>
-		  </motion.div>
-		</LayoutWrapper>
-	      </MotionConfig>
-
-	      <Toaster/>
-	      </KeyboardShortcutsProvider>
-	    </UnsavedChangesGuardProvider>
-	  </DialogueProvider>
-	</BrowserRouter>
-      </>)
+	  <Toaster/>
+	  </KeyboardShortcutsProvider>
+	</UnsavedChangesGuardProvider>
+      </DialogueProvider>)
 }
 
+const router = createBrowserRouter ([{
+    path: '*',
+    element: <RoutedApp/> }])
+
+const App: FC = () => (
+    <>
+      <RouteBlockerOverlay/>
+      {import.meta.env.DEV && <DevModeWatermark/>}
+      <RouterProvider router={router}/>
+    </>)
+
 export default App

frontend/src/components/PostEditForm.test.tsx

@@ -78,19 +78,23 @@ describe ('PostEditForm', () => {
 
     render (<PostEditForm post={post} onSave={vi.fn ()}/>)
 
-    expect (screen.getByPlaceholderText ('例: 2 / 2.5 / 1:23')).toHaveValue ('180.5')
+    expect (screen.getByText ('動画時間').parentElement?.querySelector ('input'))
+	.toHaveValue ('180.5')
 
     const tags = screen.getAllByRole ('textbox')[2]
     fireEvent.change (tags, { target: { value: 'general-tag' } })
-    expect (screen.queryByPlaceholderText ('例: 2 / 2.5 / 1:23')).not.toBeInTheDocument ()
+    expect (screen.queryByText ('動画時間')).not.toBeInTheDocument ()
 
     fireEvent.change (tags, {
       target: { value: '動画 general-tag' },
     })
-    expect (screen.getByPlaceholderText ('例: 2 / 2.5 / 1:23')).toHaveValue ('180.5')
+    expect (screen.getByText ('動画時間').parentElement?.querySelector ('input'))
+	.toHaveValue ('180.5')
   })
 
-  it ('shows deduplicated original-created endpoint errors on the shared datetime field', async () => {
+  it (
+      'shows deduplicated original-created endpoint errors on the shared datetime field',
+      async () => {
     const post = buildPost ()
     api.isApiError.mockReturnValue (true)
     postsApi.updatePost.mockRejectedValueOnce ({
@@ -112,5 +116,5 @@ describe ('PostEditForm', () => {
     expect (await screen.findByText ('日時を確認してください．')).toBeInTheDocument ()
     expect (screen.getByText ('終了を確認してください．')).toBeInTheDocument ()
     expect (screen.getAllByText ('日時を確認してください．')).toHaveLength (1)
-  })
+      })
 })

frontend/src/components/PostOriginalCreatedTimeField.test.tsx

@@ -73,7 +73,7 @@ describe ('PostOriginalCreatedTimeField', () => {
             setOriginalCreatedBefore={vi.fn ()}/>,
     )
 
-    const input = screen.getDisplayValue ('2024-01-01T12:34')
+    const input = screen.getByDisplayValue ('2024-01-01T12:34')
     fireEvent.change (input, { target: { value: '2024-01-01T12:35' } })
 
     expect (setFrom).toHaveBeenCalledWith ('2024-01-01T03:35Z')

frontend/src/components/PostOriginalCreatedTimeField.tsx

@@ -24,10 +24,10 @@ const PostOriginalCreatedTimeField: FC<Props> = (
       <FormField label="オリジナルの作成日時" messages={errors}>
 	  {({ describedBy, invalid }) => (
 	      <>
-		<div className="my-1 flex flex-col gap-2 sm:flex-row sm:items-start">
-		  <div className="min-w-0 flex-1">
+		<div className="my-1 flex">
+		  <div className="w-80">
 		    <DateTimeField
-			className="w-full"
+			className="mr-2"
 			disabled={disabled ?? false}
 			aria-describedby={describedBy}
 			aria-invalid={invalid}
@@ -61,10 +61,10 @@ const PostOriginalCreatedTimeField: FC<Props> = (
 		  </div>
 		</div>
 
-		<div className="my-1 flex flex-col gap-2 sm:flex-row sm:items-start">
-		  <div className="min-w-0 flex-1">
+		<div className="my-1 flex">
+		  <div className="w-80">
 		    <DateTimeField
-			className="w-full"
+			className="mr-2"
 			disabled={disabled}
 			aria-describedby={describedBy}
 			aria-invalid={invalid}

frontend/src/components/PrefetchLink.tsx

@@ -6,7 +6,6 @@ import { createPath, useNavigate } from 'react-router-dom'
 import { useOverlayStore } from '@/components/RouteBlockerOverlay'
 import { prefetchForURL } from '@/lib/prefetchers'
 import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
-import { useUnsavedChangesGuard } from '@/lib/useUnsavedChangesGuard'
 import { cn } from '@/lib/utils'
 
 import type { AnchorHTMLAttributes, MouseEvent, TouchEvent } from 'react'
@@ -36,7 +35,6 @@ export default forwardRef<HTMLAnchorElement, Props> (({
   const navigate = useNavigate ()
   const qc = useQueryClient ()
   const behaviourSettings = useClientBehaviourSettings ()
-  const { confirmDiscardNavigation } = useUnsavedChangesGuard ()
   const linkPreloadMode = behaviourSettings.linkPreload ?? 'intent'
   const path = useMemo (
       () => typeof to === 'string' ? to : createPath (to),
@@ -45,10 +43,6 @@ export default forwardRef<HTMLAnchorElement, Props> (({
   const url = useMemo (() => {
     return (new URL (path, window.location.origin)).toString ()
   }, [path])
-  const nextPathname = useMemo (
-      () => (new URL (path, window.location.origin)).pathname,
-      [path],
-  )
   const setOverlay = useOverlayStore (s => s.setActive)
 
   const doPrefetch = async () => {
@@ -93,13 +87,6 @@ export default forwardRef<HTMLAnchorElement, Props> (({
 
       ev.preventDefault ()
 
-      if (nextPathname !== window.location.pathname)
-	{
-	  const confirmed = await confirmDiscardNavigation ()
-	  if (!(confirmed))
-	    return
-	}
-
       flushSync (() => {
 	setOverlay (true)
       })

frontend/src/components/TagLink.tsx

@@ -4,9 +4,13 @@ import { cn } from '@/lib/utils'
 
 import type { ComponentProps, CSSProperties, FC, HTMLAttributes } from 'react'
 
-import type { Tag } from '@/types'
+import type { Category, Tag } from '@/types'
 
-type CommonProps = { 
+type LightweightTag = {
+    name:     string
+    category: Category }
+
+type FullCommonProps = {
     tag:        Tag
     nestLevel?: number
     truncateOnMobile?: boolean
@@ -14,18 +18,43 @@ type CommonProps = {
     withCount?: boolean }
 
 type PropsWithLink =
-    & CommonProps
+    & FullCommonProps
     & { linkFlg?: true }
     & Partial<ComponentProps<typeof PrefetchLink>>
 
 type PropsWithoutLink =
-    & CommonProps
+    & FullCommonProps
     & { linkFlg: false }
     & Partial<HTMLAttributes<HTMLSpanElement>>
 
+type LightweightPropsWithLink =
+    & {
+	tag:              LightweightTag
+	nestLevel?:       number
+	truncateOnMobile?: boolean
+	withWiki:         false
+	withCount:        false
+	linkFlg?:         true }
+    & Partial<ComponentProps<typeof PrefetchLink>>
+
+type LightweightPropsWithoutLink =
+    & {
+	tag:              LightweightTag
+	nestLevel?:       number
+	truncateOnMobile?: boolean
+	withWiki:         false
+	withCount:        false
+	linkFlg:          false }
+    & Partial<HTMLAttributes<HTMLSpanElement>>
+
 type Props =
     | PropsWithLink
     | PropsWithoutLink
+    | LightweightPropsWithLink
+    | LightweightPropsWithoutLink
+
+const isFullTag = (tag: Tag | LightweightTag): tag is Tag =>
+    'id' in tag
 
 
 const TagLink: FC<Props> = ({ tag,
@@ -46,16 +75,18 @@ const TagLink: FC<Props> = ({ tag,
   const spanClass = 'tag-link-colour'
   const linkClass = 'tag-link-colour tag-link-hover-colour'
   const textClass = 'group min-w-0 max-w-full overflow-hidden align-bottom'
-  const rootClass =
-      'inline-flex min-w-0 max-w-full flex-nowrap items-stretch align-baseline gap-x-1 md:items-baseline'
   const markerWrapClass = 'shrink-0 self-start md:self-auto'
   const countClass = 'shrink-0 self-end md:self-auto'
+  const matchedAlias = isFullTag (tag) ? tag.matchedAlias : null
   const textTitle = title
-      ?? (tag.matchedAlias == null ? tag.name : `${ tag.matchedAlias } → ${ tag.name }`)
+      ?? (matchedAlias == null ? tag.name : `${ matchedAlias } → ${ tag.name }`)
 
   return (
-      <span className={rootClass}>
-	{(linkFlg && withWiki) && (
+      <span
+	  className={cn (
+	      'inline-flex min-w-0 max-w-full flex-nowrap items-stretch align-baseline',
+	      'gap-x-1 md:items-baseline')}>
+	{(linkFlg && withWiki && isFullTag (tag)) && (
 	    <span className={markerWrapClass}>
 	      {(tag.materialId != null || tag.hasWiki || tag.hasDeerjikists)
 	       ? (
@@ -118,7 +149,7 @@ const TagLink: FC<Props> = ({ tag,
 		style={{ paddingLeft: `${ (nestLevel - 1) }rem` }}>
 	      ↳
 	    </span>)}
-	{tag.matchedAlias != null && (
+	{matchedAlias != null && (
 	    <>
 	      <span
 		  title={textTitle}
@@ -126,7 +157,7 @@ const TagLink: FC<Props> = ({ tag,
 		  style={colourStyle}
 		  {...props}>
 		<ResponsiveMarqueeText
-		    text={tag.matchedAlias}
+		    text={matchedAlias}
 		    title={textTitle}
 		    truncateOnMobile={truncateOnMobile}/>
 	      </span>
@@ -156,7 +187,7 @@ const TagLink: FC<Props> = ({ tag,
 		  title={textTitle}
 		  truncateOnMobile={truncateOnMobile}/>
 	    </span>)}
-	{withCount && (
+	{(withCount && isFullTag (tag)) && (
 	    <span className={countClass}>{tag.postCount}</span>)}
       </span>)
 }

frontend/src/components/TopNav.test.tsx

@@ -17,19 +17,21 @@ describe ('menuOutline', () => {
     for (const role of ['member', 'admin'] as const)
       {
 	expect (submenuItem (role, '広場', '追加')?.visible).toBe (true)
-	expect (submenuItem (role, '広場', '取込')?.visible).toBe (true)
 	expect (submenuItem (role, '素材', '追加')?.visible).toBe (true)
 	expect (submenuItem (role, 'Wiki', '新規')?.visible).toBe (true)
 	expect (submenuItem (role, 'Wiki', '編輯')?.visible).toBe (true)
       }
 
     expect (submenuItem ('guest', '広場', '追加')?.visible).toBe (false)
-    expect (submenuItem ('guest', '広場', '取込')?.visible).toBe (false)
     expect (submenuItem ('guest', '素材', '追加')?.visible).toBe (false)
     expect (submenuItem ('guest', 'Wiki', '新規')?.visible).toBe (false)
     expect (submenuItem ('guest', 'Wiki', '編輯')?.visible).toBe (false)
   })
 
+  it ('uses /posts/new as the post creation entrypoint', () => {
+    expect (submenuItem ('member', '広場', '追加')?.to).toBe ('/posts/new')
+  })
+
   it ('keeps material suppression admin-only', () => {
     expect (submenuItem ('member', '素材', '抑止')?.visible).toBe (false)
     expect (submenuItem ('admin', '素材', '抑止')?.visible).toBe (true)

frontend/src/components/TopNav.tsx

@@ -45,7 +45,6 @@ export const menuOutline = (
 	  { name: '一覧', to: '/posts' },
 	  { name: '検索', to: '/posts/search' },
 	  { name: '追加', to: '/posts/new', visible: editable },
-	  { name: '取込', to: '/posts/import', visible: editable },
 	  { name: '全体履歴', to: '/posts/changes' },
 	  { name: 'ヘルプ', to: '/wiki/ヘルプ:広場' }] },
       { name: 'タグ', to: '/tags', subMenu: [

frontend/src/components/dialogues/DialogueProvider.test.tsx

@@ -80,7 +80,9 @@ describe ('DialogueProvider', () => {
     expect (dialogue).toHaveClass ('max-h-[calc(100dvh-1rem)]', 'flex-col', 'max-w-3xl')
     await waitFor (() => expect (screen.getByRole ('button', { name: '左操作' }))
 	.toBeInTheDocument ())
-    expect (screen.getByRole ('button', { name: '左操作' })).toHaveClass ('w-full', 'sm:w-auto')
+    expect (screen.getByRole ('button', { name: '左操作' })).toHaveClass (
+	'w-full',
+	'md:w-auto')
     fireEvent.click (screen.getByRole ('button', { name: '左操作' }))
 
     await waitFor (() => expect (action).toHaveBeenCalledTimes (1))

frontend/src/components/dialogues/DialogueProvider.tsx

@@ -215,12 +215,12 @@ const DialogueProvider: FC<Props> = ({ children }) => {
 
 		       <DialogFooter
 			   className="shrink-0 flex-col gap-2 pt-4
-				      sm:flex-row sm:justify-between sm:gap-0 sm:space-x-0">
-			 <div className="flex w-full flex-col gap-2 sm:w-auto sm:flex-row">
+				      md:flex-row md:justify-between md:gap-0 md:space-x-0">
+			 <div className="flex w-full flex-col gap-2 md:w-auto md:flex-row">
 			   {startActions.map (action => (
 			       <Button
 				   key={action.label}
-				   className="w-full sm:w-auto"
+				   className="w-full md:w-auto"
 				   variant={action.variant === 'danger'
 				       ? 'destructive'
 				       : 'default'}
@@ -232,9 +232,9 @@ const DialogueProvider: FC<Props> = ({ children }) => {
 			       </Button>))}
 			 </div>
 
-			 <div className="flex w-full flex-col gap-2 sm:w-auto sm:flex-row">
+			 <div className="flex w-full flex-col gap-2 md:w-auto md:flex-row">
 			   <Button
-			       className="w-full sm:w-auto"
+			       className="w-full md:w-auto"
 			       variant="outline"
 			       onClick={() => closeRequest (active.id)}
 			       disabled={pendingIds.includes (active.id)
@@ -245,7 +245,7 @@ const DialogueProvider: FC<Props> = ({ children }) => {
 			   {endActions.map (action => (
 			       <Button
 				   key={action.label}
-				   className="w-full sm:w-auto"
+				   className="w-full md:w-auto"
 				   variant={action.variant === 'danger'
 				       ? 'destructive'
 				       : 'default'}

frontend/src/components/posts/PostCoreDataFields.tsx

@@ -0,0 +1,94 @@
+import PostOriginalCreatedTimeField from '@/components/PostOriginalCreatedTimeField'
+import PostTagsField from '@/components/posts/PostTagsField'
+import PostTextField from '@/components/posts/PostTextField'
+
+import type { FC, ReactNode } from 'react'
+
+type TextMessages = string[] | undefined
+
+type CoreField = {
+  value:    string
+  onChange: (value: string) => void
+  errors?:  TextMessages
+  warnings?: TextMessages
+  disabled?: boolean }
+
+type OriginalCreatedField = {
+  originalCreatedAt?:     TextMessages
+  originalCreatedFrom?:   TextMessages
+  originalCreatedBefore?: TextMessages }
+
+type PostCoreDataFieldsProps = {
+  title: {
+    value:     string
+    onChange:  (value: string) => void
+    errors?:   TextMessages
+    warnings?: TextMessages
+    disabled?: boolean
+    after?:    ReactNode }
+  originalCreated: {
+    disabled?:                boolean
+    originalCreatedFrom:      string | null
+    setOriginalCreatedFrom:   (value: string | null) => void
+    originalCreatedBefore:    string | null
+    setOriginalCreatedBefore: (value: string | null) => void
+    errors?:                  OriginalCreatedField }
+  tags: {
+    value:     string
+    onChange:  (value: string) => void
+    errors?:   TextMessages
+    warnings?: TextMessages
+    disabled?: boolean
+    rows?:     number }
+  parentPostIds: CoreField }
+
+const groupedMessages = (...values: (TextMessages | null | undefined)[]): string[] =>
+    [...new Set (values.flatMap (value => value ?? []))]
+
+
+const PostCoreDataFields: FC<PostCoreDataFieldsProps> = (
+    { title,
+      originalCreated,
+      tags,
+      parentPostIds },
+) => (
+    <>
+      <PostTextField
+          label="タイトル"
+          value={title.value}
+          disabled={title.disabled}
+          warnings={title.warnings}
+          errors={title.errors}
+          after={title.after}
+          onChange={title.onChange}/>
+
+      <PostOriginalCreatedTimeField
+          disabled={originalCreated.disabled}
+          originalCreatedFrom={originalCreated.originalCreatedFrom}
+          setOriginalCreatedFrom={originalCreated.setOriginalCreatedFrom}
+          originalCreatedBefore={originalCreated.originalCreatedBefore}
+          setOriginalCreatedBefore={originalCreated.setOriginalCreatedBefore}
+          errors={groupedMessages (
+              originalCreated.errors?.originalCreatedAt,
+              originalCreated.errors?.originalCreatedFrom,
+              originalCreated.errors?.originalCreatedBefore)}/>
+
+      <PostTagsField
+          tags={tags.value}
+          disabled={tags.disabled}
+          setTags={tags.onChange}
+          warnings={tags.warnings}
+          errors={tags.errors}
+          rows={tags.rows}/>
+
+      <PostTextField
+          label="親投稿"
+          value={parentPostIds.value}
+          disabled={parentPostIds.disabled}
+          warnings={parentPostIds.warnings}
+          errors={parentPostIds.errors}
+          onChange={parentPostIds.onChange}/>
+    </>)
+
+export default PostCoreDataFields
+export type { PostCoreDataFieldsProps }

frontend/src/components/posts/PostCreationDataFields.tsx

@@ -0,0 +1,48 @@
+import PostCoreDataFields from '@/components/posts/PostCoreDataFields'
+import PostTextField from '@/components/posts/PostTextField'
+
+import type { FC, ReactNode } from 'react'
+
+import type { PostCoreDataFieldsProps } from '@/components/posts/PostCoreDataFields'
+
+type TextMessages = string[] | undefined
+
+type Props = {
+  url: {
+    value:       string
+    onChange:    (value: string) => void
+    errors?:     TextMessages
+    warnings?:   TextMessages
+    disabled?:   boolean
+    type?:       string
+    placeholder?: string }
+  thumbnailField: ReactNode
+  core:           PostCoreDataFieldsProps
+  extraFields?:   ReactNode }
+
+
+const PostCreationDataFields: FC<Props> = (
+    { url,
+      thumbnailField,
+      core,
+      extraFields },
+) => (
+    <>
+      <PostTextField
+          label="URL"
+          type={url.type}
+          value={url.value}
+          disabled={url.disabled}
+          warnings={url.warnings}
+          errors={url.errors}
+          placeholder={url.placeholder}
+          onChange={url.onChange}/>
+
+      {thumbnailField}
+
+      <PostCoreDataFields {...core}/>
+
+      {extraFields}
+    </>)
+
+export default PostCreationDataFields

frontend/src/components/posts/PostCreationDataFieldsUsage.test.tsx

@@ -0,0 +1,31 @@
+import { render, screen } from '@testing-library/react'
+import { describe, expect, it, vi } from 'vitest'
+
+import { buildPostImportRow } from '@/test/postImportFactories'
+
+import type { DialogueFormControls } from '@/lib/dialogues/useDialogue'
+
+const sharedFieldsSpy = vi.hoisted (() => vi.fn (() => <div data-testid="shared-fields"/>))
+
+vi.mock ('@/components/posts/PostCreationDataFields', () => ({
+  default: sharedFieldsSpy,
+}))
+
+describe ('PostCreationDataFields usage', () => {
+  it ('is used by PostImportRowForm', async () => {
+    const { default: PostImportRowForm } = await import (
+        '@/components/posts/import/PostImportRowForm')
+
+    render (
+        <PostImportRowForm
+            row={buildPostImportRow ()}
+            controls={{
+              close: vi.fn (),
+              confirm: vi.fn (),
+              setActions: vi.fn (),
+            } as DialogueFormControls}
+            onSave={vi.fn ()}/>)
+
+    expect (screen.getByTestId ('shared-fields')).toBeInTheDocument ()
+  })
+})

frontend/src/components/posts/PostDurationField.tsx

@@ -21,8 +21,7 @@ const PostDurationField: FC<Props> = (
         onChange={onChange}
         errors={errors}
         disabled={disabled}
-        type="text"
-        placeholder="例: 2 / 2.5 / 1:23"/>
+        type="text"/>
 )
 
 export default PostDurationField

frontend/src/components/posts/PostTextField.tsx

@@ -14,7 +14,8 @@ type Props = {
   type?:        string
   placeholder?: string
   className?:   string
-  after?:       ReactNode }
+  after?:       ReactNode
+  onBlur?:      () => void }
 
 
 const PostTextField: FC<Props> = (
@@ -27,7 +28,8 @@ const PostTextField: FC<Props> = (
       type = 'text',
       placeholder,
       className,
-      after },
+      after,
+      onBlur },
 ) => (
     <FormField label={label} messages={errors}>
       {({ describedBy, invalid }) => (
@@ -37,6 +39,7 @@ const PostTextField: FC<Props> = (
                 value={value}
                 disabled={disabled}
                 placeholder={placeholder}
+                onBlur={onBlur}
                 onChange={ev => onChange (ev.target.value)}
                 aria-describedby={describedBy}
                 aria-invalid={invalid}

frontend/src/components/posts/PostThumbnailPreview.test.tsx

@@ -1,4 +1,4 @@
-import { render, screen } from '@testing-library/react'
+import { fireEvent, render, screen } from '@testing-library/react'
 import { describe, expect, it } from 'vitest'
 
 import PostThumbnailPreview from '@/components/posts/PostThumbnailPreview'
@@ -9,4 +9,28 @@ describe ('PostThumbnailPreview', () => {
 
     expect (screen.getByRole ('img')).toHaveAttribute ('src', 'blob:preview')
   })
+
+  it ('renders an empty thumbnail frame without text when the URL is empty', () => {
+    const { container } = render (
+        <PostThumbnailPreview url="" className="h-10 w-10"/>)
+
+    expect (screen.queryByRole ('img')).toBeNull ()
+    expect (screen.queryByText ('サムネールを表示できません')).toBeNull ()
+    expect (screen.queryByText ('なし')).toBeNull ()
+    expect (container.querySelector ('div.rounded.border.bg-muted')).not.toBeNull ()
+    expect (container.textContent).toBe ('')
+  })
+
+  it ('renders an empty thumbnail frame without text when image loading fails', () => {
+    const { container } = render (
+        <PostThumbnailPreview url="blob:preview" className="h-10 w-10"/>)
+
+    fireEvent.error (screen.getByRole ('img'))
+
+    expect (screen.queryByRole ('img')).toBeNull ()
+    expect (screen.queryByText ('サムネールを表示できません')).toBeNull ()
+    expect (screen.queryByText ('なし')).toBeNull ()
+    expect (container.querySelector ('div.rounded.border.bg-muted')).not.toBeNull ()
+    expect (container.textContent).toBe ('')
+  })
 })

frontend/src/components/posts/PostThumbnailPreview.tsx

@@ -1,49 +1,63 @@
 import { useEffect, useState } from 'react'
 
+import { cn } from '@/lib/utils'
+
 import type { FC } from 'react'
 
 type Props = {
   url:        string
+  file?:      File
   alt?:       string
-  className?: string }
+  className?: string
+  referrerPolicy?: 'no-referrer' }
 
 
 const PostThumbnailPreview: FC<Props> = (
-    { url, alt = 'サムネール', className = 'h-16 w-16' },
+    { url,
+      file,
+      alt = 'サムネール',
+      className = 'h-16 w-16',
+      referrerPolicy },
 ) => {
   const [failed, setFailed] = useState (false)
+  const [fileUrl, setFileUrl] = useState<string | null> (null)
 
   useEffect (() => {
     setFailed (false)
-  }, [url])
+  }, [file, url])
 
-  if (!(url))
-    {
-      return (
-          <div
-              className={`${ className } flex items-center justify-center rounded border
-                          border-border bg-muted text-xs text-muted-foreground`}>
-            なし
-          </div>)
+  useEffect (() => {
+    if (file == null)
+      {
+        setFileUrl (null)
+        return
+      }
+
+    const nextUrl = URL.createObjectURL (file)
+    setFileUrl (nextUrl)
+
+    return () => {
+      URL.revokeObjectURL (nextUrl)
     }
+  }, [file])
 
-  if (failed)
+  const resolvedUrl = url.trim () !== '' ? url : (fileUrl ?? '')
+
+  if (resolvedUrl === '' || failed)
     {
       return (
           <div
-              className={`${ className } flex items-center justify-center rounded border
-                          border-amber-300 bg-amber-50 p-2 text-center text-xs
-                          text-amber-700 dark:border-amber-900 dark:bg-amber-950
-                          dark:text-amber-200`}>
-            サムネールを表示できません
-          </div>)
+              className={cn (
+                  className,
+                  'rounded border border-border bg-muted')}/>)
     }
 
   return (
       <img
-          src={url}
+          src={resolvedUrl}
           alt={alt}
-          className={`${ className } rounded border border-border object-cover`}
+          referrerPolicy={referrerPolicy}
+          className={cn (className, 'rounded border border-border object-cover')}
           onError={() => setFailed (true)}/>)
 }
 

frontend/src/components/posts/import/PostImportRowForm.test.tsx

@@ -85,7 +85,7 @@ describe ('PostImportRowForm', () => {
   it ('marks edited fields and areas invalid from field errors', () => {
     const row = buildPostImportRow ({
       validationErrors: { url: ['URL error'], tags: ['tag error'] },
-      importErrors: { duration: ['duration error'] },
+      importErrors: { title: ['title error'] },
       fieldWarnings: { title: ['title warning'] } })
 
     render (
@@ -96,7 +96,7 @@ describe ('PostImportRowForm', () => {
 
     expect (screen.getByText ('URL error')).toBeInTheDocument ()
     expect (screen.getByText ('tag error')).toBeInTheDocument ()
-    expect (screen.getByText ('duration error')).toBeInTheDocument ()
+    expect (screen.getByText ('title error')).toBeInTheDocument ()
     expect (screen.getByText ('title warning')).toBeInTheDocument ()
     expect (screen.getAllByRole ('textbox').filter (
 	textbox => textbox.getAttribute ('aria-invalid') === 'true')).toHaveLength (3)
@@ -134,7 +134,9 @@ describe ('PostImportRowForm', () => {
       resetRequested: false })
   })
 
-  it ('keeps the shared duration and tags string contract without leaking file upload UI', async () => {
+  it (
+      'shows upload input only when the thumbnail URL is blank',
+      async () => {
     let actions: DialogueFormAction[] = []
     const controls: DialogueFormControls = {
       close: vi.fn (),
@@ -152,8 +154,20 @@ describe ('PostImportRowForm', () => {
             onSave={onSave}/>)
     await waitFor (() => expect (actions.length).toBe (2))
 
-    expect (container.querySelector ('input[type="file"]')).toBeNull ()
-    expect (screen.getByPlaceholderText ('例: 2 / 2.5 / 1:23')).toHaveValue ('2')
+    const labels = Array.from (container.querySelectorAll ('label'))
+        .map (node => node.textContent?.trim ())
+
+    expect (labels.slice (0, 6)).toEqual ([
+      'URL',
+      'サムネール',
+      'タイトル',
+      'オリジナルの作成日時',
+      'タグ',
+      '親投稿'])
+    expect (container.querySelector ('input[type="file"]')).toHaveAttribute (
+	'accept',
+	'image/*')
+    expect (screen.queryByPlaceholderText ('例: 2 / 2.5 / 1:23')).not.toBeInTheDocument ()
     expect (screen.getByDisplayValue ('tag1')).toBeInTheDocument ()
 
     await act (async () => {
@@ -162,10 +176,9 @@ describe ('PostImportRowForm', () => {
 
     expect (onSave).toHaveBeenCalledWith ({
       draft: expect.objectContaining ({
-        duration: '2',
         tags: 'tag1' }),
       resetRequested: false })
-  })
+      })
 
   it ('keeps reset enabled when the value matches but provenance still differs', async () => {
     const row = buildPostImportRow ({
@@ -178,7 +191,6 @@ describe ('PostImportRowForm', () => {
           thumbnailBase: '',
           originalCreatedFrom: '',
           originalCreatedBefore: '',
-          duration: '',
           tags: '',
           parentPostIds: '' },
         provenance: {
@@ -187,7 +199,6 @@ describe ('PostImportRowForm', () => {
           thumbnailBase: 'automatic',
           originalCreatedFrom: 'automatic',
           originalCreatedBefore: 'automatic',
-          duration: 'automatic',
           tags: 'automatic',
           parentPostIds: 'automatic' },
         tagSources: { automatic: '', manual: '' },
@@ -210,7 +221,9 @@ describe ('PostImportRowForm', () => {
     expect (actions.find (action => action.label === '変更をリセット')?.disabled).toBe (false)
   })
 
-  it ('disables every field while save validation is pending and re-enables them afterwards', async () => {
+  it (
+      'disables every field while save validation is pending and re-enables them afterwards',
+      async () => {
     let actions: DialogueFormAction[] = []
     let resolveSave:
         ((value: { saved: boolean
@@ -234,8 +247,9 @@ describe ('PostImportRowForm', () => {
             onSave={onSave}/>)
     await waitFor (() => expect (actions.length).toBe (2))
 
+    let savePromise: Promise<boolean | void> | undefined
     await act (async () => {
-      await actions.find (action => action.label === '編輯内容を保存')?.onSelect ()
+      savePromise = actions.find (action => action.label === '編輯内容を保存')?.onSelect ()
     })
 
     await waitFor (() => {
@@ -249,6 +263,9 @@ describe ('PostImportRowForm', () => {
       row: buildPostImportRow ({
         attributes: { title: 'draft title' },
         validationErrors: { title: ['タイトルを確認してください．'] } }) })
+    await act (async () => {
+      await savePromise
+    })
 
     await waitFor (() => {
       screen.getAllByRole ('textbox').forEach (textbox => {
@@ -257,5 +274,5 @@ describe ('PostImportRowForm', () => {
     })
     expect (screen.getByDisplayValue ('draft title')).toBeInTheDocument ()
     expect (screen.getByText ('タイトルを確認してください．')).toBeInTheDocument ()
-  })
+      })
 })

frontend/src/components/posts/import/PostImportRowForm.tsx

@@ -1,17 +1,17 @@
 import { useCallback, useEffect, useMemo, useState } from 'react'
 
-import PostOriginalCreatedTimeField from '@/components/PostOriginalCreatedTimeField'
 import FieldError from '@/components/common/FieldError'
 import FieldWarning from '@/components/common/FieldWarning'
+import PostCreationDataFields from '@/components/posts/PostCreationDataFields'
 import PostDurationField from '@/components/posts/PostDurationField'
-import PostTagsField from '@/components/posts/PostTagsField'
 import PostTextField from '@/components/posts/PostTextField'
 import PostImportThumbnailPreview from '@/components/posts/import/PostImportThumbnailPreview'
+import { hasThumbnailBaseValue, hasVideoTag } from '@/lib/postImportRows'
 
 import type { FC } from 'react'
 
-import type { PostImportEditableDraft, PostImportRow } from '@/lib/postImportSession'
 import type { DialogueFormControls } from '@/lib/dialogues/useDialogue'
+import type { PostImportEditableDraft, PostImportRow } from '@/lib/postImportTypes'
 
 type Draft = PostImportEditableDraft
 
@@ -23,15 +23,18 @@ type Props = {
 			     saved: boolean
 			     row:   PostImportRow | null }> }
 
+const THUMBNAIL_MISSING_WARNING = 'サムネールなし'
+
 const buildDraft = (row: PostImportRow): Draft => ({
     url: row.url,
     title: String (row.attributes.title ?? ''),
     thumbnailBase: String (row.attributes.thumbnailBase ?? ''),
     originalCreatedFrom: String (row.attributes.originalCreatedFrom ?? ''),
     originalCreatedBefore: String (row.attributes.originalCreatedBefore ?? ''),
-    duration: String (row.attributes.duration ?? ''),
     tags: String (row.attributes.tags ?? ''),
-    parentPostIds: String (row.attributes.parentPostIds ?? '') })
+    parentPostIds: String (row.attributes.parentPostIds ?? ''),
+    duration: String (row.attributes.duration ?? ''),
+    thumbnailFile: row.thumbnailFile })
 
 const buildResetDraft = (row: PostImportRow): Draft => ({
     url: row.resetSnapshot.url,
@@ -39,9 +42,10 @@ const buildResetDraft = (row: PostImportRow): Draft => ({
     thumbnailBase: String (row.resetSnapshot.attributes.thumbnailBase ?? ''),
     originalCreatedFrom: String (row.resetSnapshot.attributes.originalCreatedFrom ?? ''),
     originalCreatedBefore: String (row.resetSnapshot.attributes.originalCreatedBefore ?? ''),
-    duration: String (row.resetSnapshot.attributes.duration ?? ''),
     tags: String (row.resetSnapshot.attributes.tags ?? ''),
-    parentPostIds: String (row.resetSnapshot.attributes.parentPostIds ?? '') })
+    parentPostIds: String (row.resetSnapshot.attributes.parentPostIds ?? ''),
+    duration: String (row.resetSnapshot.attributes.duration ?? ''),
+    thumbnailFile: undefined })
 
 const groupedMessages = (...values: (string[] | undefined)[]): string[] =>
     [...new Set (values.flatMap (value => value ?? []))]
@@ -52,9 +56,10 @@ const sameDraft = (left:  Draft, right: Draft): boolean =>
     && left.thumbnailBase === right.thumbnailBase
     && left.originalCreatedFrom === right.originalCreatedFrom
     && left.originalCreatedBefore === right.originalCreatedBefore
-    && left.duration === right.duration
     && left.tags === right.tags
     && left.parentPostIds === right.parentPostIds
+    && left.duration === right.duration
+    && left.thumbnailFile === right.thumbnailFile
 
 const sameProvenance = (
     current: PostImportRow['provenance'],
@@ -69,6 +74,24 @@ const sameTagSources = (
     (current?.automatic ?? '') === reset.automatic
     && (current?.manual ?? '') === reset.manual
 
+const sameWarnings = (
+    current: PostImportRow,
+    reset:   PostImportRow['resetSnapshot'],
+): boolean =>
+    JSON.stringify (current.fieldWarnings) === JSON.stringify (reset.fieldWarnings)
+    && JSON.stringify (current.baseWarnings) === JSON.stringify (reset.baseWarnings)
+
+const thumbnailWarnings = (
+    messages:       string[] | undefined,
+    thumbnailBase:  string,
+    thumbnailFile:  File | undefined,
+): string[] => {
+  const others = (messages ?? []).filter (message => message !== THUMBNAIL_MISSING_WARNING)
+  return hasThumbnailBaseValue (thumbnailBase) || thumbnailFile != null
+      ? others
+      : [...new Set ([...others, THUMBNAIL_MISSING_WARNING])]
+}
+
 
 const PostImportRowForm: FC<Props> = (
     { row,
@@ -79,24 +102,33 @@ const PostImportRowForm: FC<Props> = (
   const [messageRow, setMessageRow] = useState<PostImportRow | null> (null)
   const [saving, setSaving] = useState (false)
   const [resetRequested, setResetRequested] = useState (false)
+  const [committedThumbnailBase, setCommittedThumbnailBase] = useState (
+      () => String (row.attributes.thumbnailBase ?? ''))
 
   useEffect (() => {
     const nextDraft = buildDraft (row)
     setDraft (nextDraft)
     setMessageRow (null)
     setResetRequested (false)
+    setCommittedThumbnailBase (String (row.attributes.thumbnailBase ?? ''))
   }, [row])
 
   const displayRow = messageRow ?? row
   const resetDraft = useMemo (
       () => buildResetDraft (row),
       [row])
+  const durationVisible = hasVideoTag (draft.tags)
+  const currentThumbnailWarnings = thumbnailWarnings (
+      displayRow.fieldWarnings.thumbnailBase,
+      draft.thumbnailBase,
+      draft.thumbnailFile)
   const resetDisabled =
       saving
       || (sameDraft (draft, resetDraft)
           && sameProvenance (row.provenance, row.resetSnapshot.provenance)
           && sameTagSources (row.tagSources, row.resetSnapshot.tagSources)
-          && row.metadataUrl === row.resetSnapshot.metadataUrl)
+          && row.metadataUrl === row.resetSnapshot.metadataUrl
+          && sameWarnings (displayRow, row.resetSnapshot))
 
   const update = <Key extends keyof Draft,> (
       key:   Key,
@@ -113,7 +145,6 @@ const PostImportRowForm: FC<Props> = (
 
     const confirmed = await controls.confirm ({
 	title: '変更をリセットしますか?',
-	description: '現在の URL に対する自動取得直後の内容へ戻します．',
 	confirmText: 'リセット',
 	cancelText: '取消',
 	variant: 'danger' })
@@ -123,6 +154,7 @@ const PostImportRowForm: FC<Props> = (
     setDraft (resetDraft)
     setResetRequested (true)
     setMessageRow (null)
+    setCommittedThumbnailBase (resetDraft.thumbnailBase)
     return false
   }, [controls, resetDisabled, resetDraft])
 
@@ -164,77 +196,103 @@ const PostImportRowForm: FC<Props> = (
 	    <div className="grid gap-6 md:grid-cols-[7rem_minmax(0,1fr)]">
 	      <div className="space-y-3 md:sticky md:top-0 md:self-start">
 		<PostImportThumbnailPreview
-		    url={draft.thumbnailBase}
+		    url={committedThumbnailBase}
+		    file={
+			hasThumbnailBaseValue (committedThumbnailBase)
+			? undefined
+			: draft.thumbnailFile}
 		    className="h-28 w-28"/>
 	      </div>
 
 	      <div className="space-y-4">
-		<PostTextField
-		    label="URL"
-		    value={draft.url}
-		    disabled={saving}
-		    warnings={displayRow.fieldWarnings.url}
-		    errors={groupedMessages (
-			displayRow.validationErrors.url,
-			displayRow.importErrors?.url)}
-		    onChange={value => update ('url', value)}/>
-		<PostTextField
-		    label="タイトル"
-		    value={draft.title}
-		    disabled={saving}
-		    warnings={displayRow.fieldWarnings.title}
-		    errors={groupedMessages (
-			displayRow.validationErrors.title,
-			displayRow.importErrors?.title)}
-		    onChange={value => update ('title', value)}/>
-		<PostTextField
-		    label="サムネール基底 URL"
-		    value={draft.thumbnailBase}
-		    disabled={saving}
-		    warnings={displayRow.fieldWarnings.thumbnailBase}
-		    errors={groupedMessages (
-			displayRow.validationErrors.thumbnailBase,
-			displayRow.importErrors?.thumbnailBase)}
-		    onChange={value => update ('thumbnailBase', value)}/>
-		<PostOriginalCreatedTimeField
-		    disabled={saving}
-		    originalCreatedFrom={draft.originalCreatedFrom || null}
-		    setOriginalCreatedFrom={value => update ('originalCreatedFrom', value ?? '')}
-		    originalCreatedBefore={draft.originalCreatedBefore || null}
-		    setOriginalCreatedBefore={value => update ('originalCreatedBefore', value ?? '')}
-		    errors={groupedMessages (
-			displayRow.validationErrors.originalCreatedAt,
-			displayRow.validationErrors.originalCreatedFrom,
-			displayRow.validationErrors.originalCreatedBefore,
-			displayRow.importErrors?.originalCreatedAt,
-			displayRow.importErrors?.originalCreatedFrom,
-			displayRow.importErrors?.originalCreatedBefore)}/>
-		<PostDurationField
-		    value={draft.duration}
-		    disabled={saving}
-		    errors={groupedMessages (
-			displayRow.validationErrors.duration,
-			displayRow.validationErrors.videoMs,
-			displayRow.importErrors?.duration,
-			displayRow.importErrors?.videoMs)}
-		    onChange={value => update ('duration', value)}/>
-		<PostTagsField
-		    tags={draft.tags}
-		    disabled={saving}
-		    setTags={value => update ('tags', value)}
-		    warnings={displayRow.fieldWarnings.tags}
-		    errors={groupedMessages (
-			displayRow.validationErrors.tags,
-			displayRow.importErrors?.tags)}
-		    rows={4}/>
-		<PostTextField
-		    label="親投稿"
-		    value={draft.parentPostIds}
-		    disabled={saving}
-		    errors={groupedMessages (
-			displayRow.validationErrors.parentPostIds,
-			displayRow.importErrors?.parentPostIds)}
-		    onChange={value => update ('parentPostIds', value)}/>
+		<PostCreationDataFields
+		    url={{
+			value: draft.url,
+			onChange: value => update ('url', value),
+			disabled: saving,
+			warnings: displayRow.fieldWarnings.url,
+			errors: groupedMessages (
+			    displayRow.validationErrors.url,
+			    displayRow.importErrors?.url) }}
+		    thumbnailField={
+			<>
+			  <PostTextField
+			      label="サムネール"
+			      value={draft.thumbnailBase}
+			      disabled={saving}
+			      warnings={currentThumbnailWarnings}
+			      errors={groupedMessages (
+				  displayRow.validationErrors.thumbnailBase,
+				  displayRow.importErrors?.thumbnailBase)}
+			      onBlur={() => {
+				if (draft.thumbnailBase.trim () !== committedThumbnailBase.trim ())
+				  setCommittedThumbnailBase (draft.thumbnailBase)
+			      }}
+			      onChange={value => update ('thumbnailBase', value)}/>
+			  {!(hasThumbnailBaseValue (draft.thumbnailBase)) && (
+			      <input
+				  type="file"
+				  accept="image/*"
+				  disabled={saving}
+				  onChange={event => {
+				    const file = event.target.files?.[0]
+				    update ('thumbnailFile', file)
+				  }}/>)}
+			</>}
+		    core={{
+			title: {
+			    value: draft.title,
+			    onChange: value => update ('title', value),
+			    disabled: saving,
+			    warnings: displayRow.fieldWarnings.title,
+			    errors: groupedMessages (
+				displayRow.validationErrors.title,
+				displayRow.importErrors?.title) },
+			originalCreated: {
+			    disabled: saving,
+			    originalCreatedFrom: draft.originalCreatedFrom || null,
+			    setOriginalCreatedFrom: value =>
+				update ('originalCreatedFrom', value ?? ''),
+			    originalCreatedBefore: draft.originalCreatedBefore || null,
+			    setOriginalCreatedBefore: value =>
+				update ('originalCreatedBefore', value ?? ''),
+			    errors: {
+				originalCreatedAt: groupedMessages (
+				    displayRow.validationErrors.originalCreatedAt,
+				    displayRow.importErrors?.originalCreatedAt),
+				originalCreatedFrom: groupedMessages (
+				    displayRow.validationErrors.originalCreatedFrom,
+				    displayRow.importErrors?.originalCreatedFrom),
+				originalCreatedBefore: groupedMessages (
+				    displayRow.validationErrors.originalCreatedBefore,
+				    displayRow.importErrors?.originalCreatedBefore) } },
+			tags: {
+			    value: draft.tags,
+			    onChange: value => update ('tags', value),
+			    disabled: saving,
+			    warnings: displayRow.fieldWarnings.tags,
+			    errors: groupedMessages (
+				displayRow.validationErrors.tags,
+				displayRow.importErrors?.tags),
+			    rows: 4 },
+			parentPostIds: {
+			    value: draft.parentPostIds,
+			    onChange: value => update ('parentPostIds', value),
+			    disabled: saving,
+			    errors: groupedMessages (
+				displayRow.validationErrors.parentPostIds,
+				displayRow.importErrors?.parentPostIds) } }}
+		    extraFields={
+			durationVisible
+			? (
+			    <PostDurationField
+				value={draft.duration}
+				onChange={value => update ('duration', value)}
+				disabled={saving}
+				errors={groupedMessages (
+				    displayRow.validationErrors.videoMs,
+				    displayRow.importErrors?.videoMs)}/>)
+			: null}/>
 		<FieldWarning messages={displayRow.baseWarnings}/>
 		<FieldError messages={displayRow.validationErrors.base}/>
 		<FieldError messages={displayRow.importErrors?.base}/>

frontend/src/components/posts/import/PostImportRowSummary.tsx

@@ -1,18 +1,32 @@
+import FieldError from '@/components/common/FieldError'
+import PostImportTagLinks from '@/components/posts/import/PostImportTagLinks'
 import { Button } from '@/components/ui/button'
 import PostImportThumbnailPreview from '@/components/posts/import/PostImportThumbnailPreview'
 import PostImportStatusBadge from '@/components/posts/import/PostImportStatusBadge'
 import { displayPostImportStatus } from '@/components/posts/import/postImportRowStatus'
-import { canEditReviewRow } from '@/lib/postImportSession'
+import {
+    canEditReviewRow,
+    canRetryResultRow,
+    hasVideoTag,
+} from '@/lib/postImportRows'
 import { cn, originalCreatedAtString } from '@/lib/utils'
 
 import type { FC } from 'react'
 
-import type { PostImportRow } from '@/lib/postImportSession'
+import type { PostImportRow } from '@/lib/postImportTypes'
 
 type Props = {
-    row:           PostImportRow
-    onEdit:        () => void
-    editDisabled?: boolean }
+    row:	      PostImportRow
+    displayNumber?:   number
+    onEdit?:	      () => void
+    onRetry?:	      () => void
+    onToggleSkip?:    (checked: boolean) => void
+    rowMessages?:     string[]
+    editDisabled?:    boolean
+    retryDisabled?:   boolean
+    skipDisabled?:    boolean
+    showActions?:     boolean
+    showSkipToggle?:  boolean }
 
 const summaryWarning = (row: PostImportRow): string | null =>
     Object.values (row.fieldWarnings ?? { }).flat ()[0]
@@ -25,95 +39,159 @@ const summaryDate = (row: PostImportRow): string =>
 	row.attributes.originalCreatedBefore?.toString () ?? null)
 
 
-const PostImportRowSummary: FC<Props> = ({ row, onEdit, editDisabled }) => {
+const PostImportRowSummary: FC<Props> = (
+    { row,
+      displayNumber,
+      onEdit,
+      onRetry,
+      onToggleSkip,
+      rowMessages,
+      editDisabled,
+      retryDisabled,
+      skipDisabled,
+      showActions = true,
+      showSkipToggle = false },
+) => {
   const warning = summaryWarning (row)
   const displayStatus = displayPostImportStatus (row)
+  const editVisible = onEdit != null
+  const editAllowed = editVisible && canEditReviewRow (row)
+  const retryAllowed = onRetry != null && canRetryResultRow (row)
+  const skipChecked = row.skipReason === 'manual'
+  const rowNumber = displayNumber ?? row.sourceRow
+  const duration = String (row.attributes.duration ?? '')
+  const showDuration = hasVideoTag (row.attributes.tags) && duration !== ''
+  const skipControl = showSkipToggle
+      ? (
+	  <label className="flex items-center gap-2 text-sm">
+	    <input
+		type="checkbox"
+		checked={skipChecked}
+		onChange={event => onToggleSkip?.(event.target.checked)}
+		disabled={skipDisabled === true}/>
+	    <span>スキップ</span>
+	  </label>)
+      : null
 
   return (
       <>
-        <div
-            className={cn (
-                'hidden items-center gap-4 rounded-lg border p-4 md:grid',
-                'md:grid-cols-[4rem_5rem_minmax(0,1fr)_auto_auto]',
-                'transition-shadow hover:shadow-sm')}>
-          <div className="space-y-1">
-            <div className="text-sm font-medium">#{row.sourceRow}</div>
-          </div>
-          <PostImportThumbnailPreview
-              url={String (row.attributes.thumbnailBase ?? '')}
-              className="h-16 w-16"/>
-          <div className="min-w-0 space-y-1">
-            <div className="line-clamp-2 text-sm font-medium">
-              {String (row.attributes.title ?? '') || '（タイトル未取得）'}
-            </div>
-            <div className="truncate text-xs text-neutral-600 dark:text-neutral-300">
-              {row.url}
-            </div>
-            <div className="truncate text-xs text-neutral-500 dark:text-neutral-400">
-              {String (row.attributes.tags ?? '') || 'タグなし'}
-            </div>
-            <div className="text-xs text-neutral-500 dark:text-neutral-400">
-              {summaryDate (row)}
-              {row.attributes.duration ? ` / ${ row.attributes.duration }` : ''}
-            </div>
-            {warning && (
-                <div className="text-xs text-amber-700 dark:text-amber-200">
-                  {warning}
-                </div>)}
-          </div>
-          <div className="space-y-1">
-            {displayStatus != null && <PostImportStatusBadge value={displayStatus}/>}
-          </div>
-          <div className="flex justify-end">
-            <Button
-                type="button"
-                variant="outline"
-                onClick={onEdit}
-                disabled={!(canEditReviewRow (row)) || editDisabled === true}>
-              編輯
-            </Button>
-          </div>
-        </div>
+	<div
+	    className={cn (
+		'hidden items-center gap-4 rounded-lg border p-4 md:grid',
+		'md:grid-cols-[4rem_5rem_minmax(0,1fr)_auto_auto]',
+		'transition-shadow hover:shadow-sm')}>
+	  <div className="space-y-1">
+	    <div className="text-sm font-medium">#{rowNumber}</div>
+	  </div>
+	  <PostImportThumbnailPreview
+	      url={String (row.attributes.thumbnailBase ?? '')}
+	      file={row.thumbnailFile}
+	      className="h-16 w-16"/>
+	  <div className="min-w-0 space-y-1">
+	    <div className="line-clamp-2 text-sm font-medium">
+	      {String (row.attributes.title ?? '')}
+	    </div>
+	    <div className="truncate text-xs text-neutral-600 dark:text-neutral-300">
+	      {row.url}
+	    </div>
+	    <PostImportTagLinks tags={row.displayTags}/>
+	    <div className="text-xs text-neutral-500 dark:text-neutral-400">
+	      {summaryDate (row)}
+	    </div>
+	    {showDuration && (
+		<div className="text-xs text-neutral-500 dark:text-neutral-400">
+		  動画時間 {duration}
+		</div>)}
+	    {warning && (
+		<div className="text-xs text-amber-700 dark:text-amber-200">
+		  {warning}
+		</div>)}
+	    <FieldError messages={rowMessages}/>
+	  </div>
+	  <div className="space-y-1">
+	    {displayStatus != null && <PostImportStatusBadge value={displayStatus}/>}
+	  </div>
+	  <div className="flex justify-end">
+	    <div className="flex items-center gap-2">
+	      {skipControl}
+	      {showActions && editVisible && (
+		  <Button
+		      type="button"
+		      variant="outline"
+		      onClick={onEdit}
+		      disabled={editDisabled === true || !(editAllowed)}>
+		    編輯
+		  </Button>)}
+	      {showActions && retryAllowed && (
+		  <Button
+		      type="button"
+		      variant="outline"
+		      onClick={onRetry}
+		      disabled={retryDisabled === true}>
+		    再試行
+		  </Button>)}
+	    </div>
+	  </div>
+	</div>
 
-        <div
-            className={cn (
-                'space-y-3 rounded-lg border p-4 md:hidden',
-                'transition-shadow hover:shadow-sm')}>
-          <div className="flex items-start gap-3">
-            <PostImportThumbnailPreview
-                url={String (row.attributes.thumbnailBase ?? '')}
-                className="h-20 w-20 shrink-0"/>
-            <div className="min-w-0 flex-1 space-y-2">
-              <div className="line-clamp-2 text-sm font-medium">
-                {String (row.attributes.title ?? '') || '（タイトル未取得）'}
-              </div>
-              <div className="truncate text-xs text-neutral-600 dark:text-neutral-300">
-                {row.url}
-              </div>
-              <div className="flex flex-wrap gap-2">
-                {displayStatus != null && <PostImportStatusBadge value={displayStatus}/>}
-              </div>
-              <div className="text-xs text-neutral-500 dark:text-neutral-400">
-                {String (row.attributes.tags ?? '') || 'タグなし'}
-              </div>
-              <div className="text-xs text-neutral-500 dark:text-neutral-400">
-                {summaryDate (row)}
-                {row.attributes.duration ? ` / ${ row.attributes.duration }` : ''}
-              </div>
-              {warning && (
-                  <div className="text-xs text-amber-700 dark:text-amber-200">
-                    {warning}
-                  </div>)}
-            </div>
-          </div>
-          <Button
-              type="button"
-              variant="outline"
-              onClick={onEdit}
-              disabled={!(canEditReviewRow (row)) || editDisabled === true}>
-            編輯
-          </Button>
-        </div>
+	<div
+	    className={cn (
+		'space-y-3 rounded-lg border p-4 md:hidden',
+		'transition-shadow hover:shadow-sm')}>
+	  <div className="text-sm font-medium">#{rowNumber}</div>
+	  <div className="flex items-start gap-3">
+	    <PostImportThumbnailPreview
+		url={String (row.attributes.thumbnailBase ?? '')}
+		file={row.thumbnailFile}
+		className="h-20 w-20 shrink-0"/>
+	    <div className="min-w-0 flex-1 space-y-2">
+	      <div className="line-clamp-2 text-sm font-medium">
+		{String (row.attributes.title ?? '')}
+	      </div>
+	      <div className="truncate text-xs text-neutral-600 dark:text-neutral-300">
+		{row.url}
+	      </div>
+	      <div className="flex flex-wrap gap-2">
+		{displayStatus != null && <PostImportStatusBadge value={displayStatus}/>}
+	      </div>
+	      <PostImportTagLinks tags={row.displayTags}/>
+	      <div className="text-xs text-neutral-500 dark:text-neutral-400">
+		{summaryDate (row)}
+	      </div>
+	      {showDuration && (
+		  <div className="text-xs text-neutral-500 dark:text-neutral-400">
+		    動画時間 {duration}
+		  </div>)}
+	      {warning && (
+		  <div className="text-xs text-amber-700 dark:text-amber-200">
+		    {warning}
+		  </div>)}
+	      <FieldError messages={rowMessages}/>
+	      {skipControl}
+	    </div>
+	  </div>
+	  {showActions && (editVisible || retryAllowed) && (
+	      <div className="flex flex-col gap-2 md:flex-row">
+		{editVisible && (
+		    <Button
+			type="button"
+			className="w-full md:w-auto"
+			variant="outline"
+			onClick={onEdit}
+			disabled={editDisabled === true || !(editAllowed)}>
+		      編輯
+		    </Button>)}
+		{retryAllowed && (
+		    <Button
+			type="button"
+			className="w-full md:w-auto"
+			variant="outline"
+			onClick={onRetry}
+			disabled={retryDisabled === true}>
+		      再試行
+		    </Button>)}
+	      </div>)}
+	</div>
       </>)
 }
 

frontend/src/components/posts/import/PostImportStatusBadge.tsx

@@ -10,13 +10,19 @@ type Props = {
 
 const LABELS: Record<PostImportBadgeValue, string> = {
     ready: '登録可能',
+    error: '登録不可',
     warning: '警告',
-    skipped: 'スキップ' }
+    skipped: 'スキップ',
+    created: '登録済み',
+    failed: '登録失敗' }
 
 const TONES: Record<PostImportBadgeValue, StatusBadgeTone> = {
     ready: 'success',
+    error: 'warning',
     warning: 'warning',
-    skipped: 'neutral' }
+    skipped: 'neutral',
+    created: 'success',
+    failed: 'warning' }
 
 
 const PostImportStatusBadge: FC<Props> = ({ value }) => (

frontend/src/components/posts/import/PostImportTagLinks.tsx

@@ -0,0 +1,36 @@
+import TagLink from '@/components/TagLink'
+
+import type { FC } from 'react'
+
+import type { PostImportDisplayTag } from '@/lib/postImportTypes'
+
+type Props = {
+  tags: PostImportDisplayTag[] | undefined }
+
+const PostImportTagLinks: FC<Props> = ({ tags }) => {
+  if (tags == null || tags.length === 0)
+    return null
+
+  return (
+      <div className="flex flex-wrap text-xs gap-x-1">
+	{tags.map (tag => {
+	  const key = `${ tag.category }:${ tag.name }:${ tag.sectionLiterals?.join ('|') ?? '' }`
+	  return (
+	      <span key={key} className="inline-flex flex-nowrap items-baseline gap-1">
+		<TagLink
+		    tag={{
+			name: tag.name,
+			category: tag.category }}
+		    linkFlg={false}
+		    withWiki={false}
+		    withCount={false}/>
+		{tag.sectionLiterals?.map (literal => (
+		    <span key={literal} className="text-xs text-neutral-500 dark:text-neutral-400">
+		      {literal}
+		    </span>))}
+	      </span>)
+	})}
+      </div>)
+}
+
+export default PostImportTagLinks

frontend/src/components/posts/import/PostImportThumbnailPreview.test.tsx

@@ -1,14 +1,8 @@
-import { render, screen, waitFor } from '@testing-library/react'
+import { fireEvent, render, screen } from '@testing-library/react'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import PostImportThumbnailPreview from '@/components/posts/import/PostImportThumbnailPreview'
 
-const api = vi.hoisted (() => ({
-  apiGet: vi.fn (),
-}))
-
-vi.mock ('@/lib/api', () => api)
-
 describe ('PostImportThumbnailPreview', () => {
   beforeEach (() => {
     vi.clearAllMocks ()
@@ -16,63 +10,50 @@ describe ('PostImportThumbnailPreview', () => {
     globalThis.URL.revokeObjectURL = vi.fn ()
   })
 
-  it ('uses a backend-fetched blob URL instead of the external thumbnail URL directly', async () => {
-    api.apiGet.mockResolvedValueOnce (new Blob (['img'], { type: 'image/png' }))
-
+  it ('renders the remote URL directly without a backend proxy', () => {
     render (
-        <PostImportThumbnailPreview
-            url="https://example.com/thumbnail.jpg"
-            className="h-10 w-10"/>)
+	<PostImportThumbnailPreview
+	    url="https://example.com/thumbnail.jpg"
+	    className="h-10 w-10"/>)
 
-    await waitFor (() => {
-      expect (screen.getByRole ('img')).toHaveAttribute ('src', 'blob:preview')
-    })
-    expect (screen.getByRole ('img')).not.toHaveAttribute (
-        'src',
-        'https://example.com/thumbnail.jpg')
-    expect (api.apiGet).toHaveBeenCalledWith ('/preview/thumbnail', {
-      params: { url: 'https://example.com/thumbnail.jpg' },
-      responseType: 'blob' })
+    expect (screen.getByRole ('img')).toHaveAttribute (
+	'src',
+	'https://example.com/thumbnail.jpg')
+    expect (screen.getByRole ('img')).toHaveAttribute (
+	'referrerpolicy',
+	'no-referrer')
   })
 
-  it ('does not render the unsafe URL directly when preview fetching fails', async () => {
-    api.apiGet.mockRejectedValueOnce (new Error ('unsafe'))
+  it ('shows the empty frame after the remote image fails', () => {
+    const { container } = render (
+	<PostImportThumbnailPreview
+	    url="https://example.com/missing.jpg"
+	    className="h-10 w-10"/>)
 
-    render (
-        <PostImportThumbnailPreview
-            url="http://127.0.0.1/private.png"
-            className="h-10 w-10"/>)
+    fireEvent.error (screen.getByRole ('img'))
 
-    expect (await screen.findByText ('サムネールを表示できません')).toBeInTheDocument ()
     expect (screen.queryByRole ('img')).toBeNull ()
+    expect (container.querySelector ('div.rounded.border.bg-muted')).not.toBeNull ()
+    expect (container.textContent).toBe ('')
   })
 
-  it ('revokes the old object URL when the source URL changes', async () => {
-    const createObjectUrlMock =
-        globalThis.URL.createObjectURL as unknown as ReturnType<typeof vi.fn>
-    createObjectUrlMock
-        .mockReturnValueOnce ('blob:first')
-        .mockReturnValueOnce ('blob:second')
-    api.apiGet
-        .mockResolvedValueOnce (new Blob (['first'], { type: 'image/png' }))
-        .mockResolvedValueOnce (new Blob (['second'], { type: 'image/png' }))
+  it ('uses and revokes an object URL only when the remote URL is blank', () => {
+    const file = new File (['image'], 'thumbnail.png', { type: 'image/png' })
+    const { rerender, unmount } = render (
+	<PostImportThumbnailPreview url="" file={file} className="h-10 w-10"/>)
 
-    const { rerender } = render (
-        <PostImportThumbnailPreview
-            url="https://example.com/first.jpg"
-            className="h-10 w-10"/>)
-    await waitFor (() => {
-      expect (screen.getByRole ('img')).toHaveAttribute ('src', 'blob:first')
-    })
+    expect (screen.getByRole ('img')).toHaveAttribute ('src', 'blob:preview')
 
     rerender (
-        <PostImportThumbnailPreview
-            url="https://example.com/second.jpg"
-            className="h-10 w-10"/>)
+	<PostImportThumbnailPreview
+	    url="https://example.com/remote.jpg"
+	    file={file}
+	    className="h-10 w-10"/>)
+    expect (screen.getByRole ('img')).toHaveAttribute (
+	'src',
+	'https://example.com/remote.jpg')
 
-    await waitFor (() => {
-      expect (screen.getByRole ('img')).toHaveAttribute ('src', 'blob:second')
-    })
-    expect (globalThis.URL.revokeObjectURL).toHaveBeenCalledWith ('blob:first')
+    unmount ()
+    expect (globalThis.URL.revokeObjectURL).toHaveBeenCalledWith ('blob:preview')
   })
 })

frontend/src/components/posts/import/PostImportThumbnailPreview.tsx

@@ -1,89 +1,25 @@
-import { useEffect, useRef, useState } from 'react'
-
 import PostThumbnailPreview from '@/components/posts/PostThumbnailPreview'
-import { apiGet } from '@/lib/api'
-import { cn } from '@/lib/utils'
 
 import type { FC } from 'react'
 
 type Props = {
   url:        string
+  file?:      File
   alt?:       string
   className?: string }
 
 
 const PostImportThumbnailPreview: FC<Props> = (
     { url,
+      file,
       alt = 'サムネール',
       className = 'h-16 w-16' },
-) => {
-  const [previewUrl, setPreviewUrl] = useState ('')
-  const [unavailable, setUnavailable] = useState (false)
-  const previewUrlRef = useRef ('')
-
-  useEffect (() => {
-    if (previewUrlRef.current)
-      {
-        URL.revokeObjectURL (previewUrlRef.current)
-        previewUrlRef.current = ''
-      }
-    setPreviewUrl ('')
-    setUnavailable (false)
-
-    if (!(url))
-      return
-
-    let active = true
-
-    const loadPreview = async () => {
-      try
-      {
-        const blob = await apiGet<Blob> ('/preview/thumbnail', {
-            params: { url },
-            responseType: 'blob' })
-        if (!(active))
-          return
-
-        const nextPreviewUrl = URL.createObjectURL (blob)
-        previewUrlRef.current = nextPreviewUrl
-        setPreviewUrl (nextPreviewUrl)
-      }
-      catch
-      {
-        if (active)
-          setUnavailable (true)
-      }
-    }
-
-    void loadPreview ()
-
-    return () => {
-      active = false
-      if (previewUrlRef.current)
-        {
-          URL.revokeObjectURL (previewUrlRef.current)
-          previewUrlRef.current = ''
-        }
-    }
-  }, [url])
-
-  if (unavailable)
-    {
-      return (
-          <div
-              className={`${ className } flex items-center justify-center rounded border
-                          border-amber-300 bg-amber-50 p-2 text-center text-xs
-                          text-amber-700 dark:border-amber-900 dark:bg-amber-950
-                          dark:text-amber-200`}>
-            サムネールを表示できません
-          </div>)
-    }
-
-  return (
-      <PostThumbnailPreview
-          url={previewUrl}
-          alt={alt}
-          className={className}/>)
-}
+) => (
+    <PostThumbnailPreview
+        url={url}
+        file={file}
+        alt={alt}
+        className={className}
+        referrerPolicy="no-referrer"/>)
 
 export default PostImportThumbnailPreview

frontend/src/components/posts/import/postImportRowStatus.test.ts

@@ -12,16 +12,18 @@ describe ('displayPostImportStatus', () => {
     expect (displayPostImportStatus (buildPostImportRow ({
       skipReason: 'existing',
       existingPostId: 2 }))).toBe ('skipped')
+    expect (displayPostImportStatus (buildPostImportRow ({
+      skipReason: 'manual' }))).toBe ('skipped')
   })
 
-  it ('does not expose validation, failure, or created states as badges', () => {
+  it ('distinguishes validation, failure, and created states', () => {
     expect (displayPostImportStatus (buildPostImportRow ({
       status: 'error',
-      validationErrors: { title: ['invalid'] } }))).toBeNull ()
+      validationErrors: { title: ['invalid'] } }))).toBe ('error')
     expect (displayPostImportStatus (buildPostImportRow ({
-      importStatus: 'failed' }))).toBeNull ()
+      importStatus: 'failed' }))).toBe ('failed')
     expect (displayPostImportStatus (buildPostImportRow ({
       importStatus: 'created',
-      createdPostId: 3 }))).toBeNull ()
+      createdPostId: 3 }))).toBe ('created')
   })
 })

frontend/src/components/posts/import/postImportRowStatus.ts

@@ -1,6 +1,12 @@
-import type { PostImportRow } from '@/lib/postImportSession'
+import type { PostImportRow } from '@/lib/postImportTypes'
 
-export type PostImportDisplayStatus = 'ready' | 'skipped' | 'warning'
+export type PostImportDisplayStatus =
+    'ready'
+    | 'error'
+    | 'skipped'
+    | 'warning'
+    | 'created'
+    | 'failed'
 
 export type PostImportBadgeValue = PostImportDisplayStatus
 
@@ -11,12 +17,18 @@ const hasWarnings = (row: PostImportRow): boolean =>
 export const displayPostImportStatus = (
     row: PostImportRow,
 ): PostImportDisplayStatus | null =>
-    (row.skipReason === 'existing' || row.importStatus === 'skipped')
+    row.status === 'pending'
+    ? null
+    : (row.importStatus === 'failed')
+    ? 'failed'
+    : (row.skipReason != null || row.importStatus === 'skipped')
     ? 'skipped'
-    : ((Object.keys (row.validationErrors ?? { }).length > 0
-	|| row.importStatus === 'failed'
-	|| row.importStatus === 'created')
-       ? null
-       : ((hasWarnings (row) || row.status === 'warning')
-	  ? 'warning'
-	  : 'ready'))
+    : (row.importStatus === 'created')
+      ? 'created'
+      : (row.status === 'error')
+      ? 'error'
+      : (Object.values (row.validationErrors ?? { }).some (messages => messages.length > 0))
+      ? 'error'
+      : ((hasWarnings (row) || row.status === 'warning')
+	 ? 'warning'
+	 : 'ready')

frontend/src/components/ui/dialog.tsx

@@ -1,10 +1,10 @@
-"use client"
+'use client'
 
-import * as React from "react"
-import * as DialogPrimitive from "@radix-ui/react-dialog"
-import { X } from "lucide-react"
+import * as DialogPrimitive from '@radix-ui/react-dialog'
+import { X } from 'lucide-react'
+import * as React from 'react'
 
-import { cn } from "@/lib/utils"
+import { cn } from '@/lib/utils'
 
 const Dialog = DialogPrimitive.Root
 
@@ -15,111 +15,109 @@ const DialogPortal = DialogPrimitive.Portal
 const DialogClose = DialogPrimitive.Close
 
 const DialogOverlay = React.forwardRef<
-  React.ElementRef<typeof DialogPrimitive.Overlay>,
-  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Overlay>
->(({ className, ...props }, ref) => (
-  <DialogPrimitive.Overlay
-    ref={ref}
-    className={cn(
-      "fixed inset-0 z-50 bg-black/80 data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0",
-      className)}
-    {...props}
-  />))
+    React.ElementRef<typeof DialogPrimitive.Overlay>,
+    React.ComponentPropsWithoutRef<typeof DialogPrimitive.Overlay>
+>(
+    ({ className, ...props }, ref) => (
+	<DialogPrimitive.Overlay
+	    ref={ref}
+	    className={cn (
+		'fixed inset-0 z-50 bg-black/80',
+		'data-[state=open]:animate-in data-[state=closed]:animate-out',
+		'data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0',
+		className)}
+	    {...props}/>))
 DialogOverlay.displayName = DialogPrimitive.Overlay.displayName
 
 const DialogContent = React.forwardRef<
-  React.ElementRef<typeof DialogPrimitive.Content>,
-  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Content>
->(({ className, children, ...props }, ref) => (
-  <DialogPortal>
-    <DialogOverlay />
-    <DialogPrimitive.Content
-      ref={ref}
-      className={cn (
-	  'fixed left-[50%] top-[50%] z-50 grid w-[calc(100%-2rem)] max-w-lg',
-	  'translate-x-[-50%] translate-y-[-50%]',
-	  'gap-5 rounded-2xl border border-border',
-	  'bg-background p-6 text-foreground shadow-2xl',
-	  'duration-200',
-	  'data-[state=open]:animate-in data-[state=closed]:animate-out',
-	  'data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0',
-	  'data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95',
-	  className)}
-      {...props}
-    >
-      {children}
+    React.ElementRef<typeof DialogPrimitive.Content>,
+    React.ComponentPropsWithoutRef<typeof DialogPrimitive.Content>
+>(
+    ({ className, children, ...props }, ref) => (
+	<DialogPortal>
+	  <DialogOverlay />
+	  <DialogPrimitive.Content
+	      ref={ref}
+	      className={cn (
+		  'fixed left-[50%] top-[50%] z-50 grid w-[calc(100%-2rem)] max-w-lg',
+		  'translate-x-[-50%] translate-y-[-50%]',
+		  'gap-5 rounded-2xl border border-border',
+		  'bg-background p-6 text-foreground shadow-2xl',
+		  'duration-200',
+		  'data-[state=open]:animate-in data-[state=closed]:animate-out',
+		  'data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0',
+		  'data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95',
+		  className)}
+	      {...props}>
+	    {children}
 
-      <DialogPrimitive.Close
-	  className={cn (
-	      'absolute left-4 top-4 rounded-full p-1',
-	      'text-slate-500 transition-colors',
-	      'hover:bg-slate-200 hover:text-slate-900',
-	      'dark:text-slate-400 dark:hover:bg-slate-700 dark:hover:text-slate-50',
-	      'focus:outline-none focus:ring-2 focus:ring-slate-400')}>
-	<X className="h-4 w-4"/>
-	<span className="sr-only">閉ぢる</span>
-      </DialogPrimitive.Close>
-    </DialogPrimitive.Content>
-  </DialogPortal>))
+	    <DialogPrimitive.Close
+		className={cn (
+		    'absolute left-4 top-4 rounded-full p-1',
+		    'text-slate-500 transition-colors',
+		    'hover:bg-slate-200 hover:text-slate-900',
+		    'dark:text-slate-400 dark:hover:bg-slate-700 dark:hover:text-slate-50',
+		    'focus:outline-none focus:ring-2 focus:ring-slate-400')}>
+	      <X className="h-4 w-4"/>
+	      <span className="sr-only">閉ぢる</span>
+	    </DialogPrimitive.Close>
+	  </DialogPrimitive.Content>
+	</DialogPortal>))
 DialogContent.displayName = DialogPrimitive.Content.displayName
 
-const DialogHeader = ({
-  className,
-  ...props
-}: React.HTMLAttributes<HTMLDivElement>) => (
-  <div
-    className={cn(
-      "flex flex-col space-y-1.5 text-center sm:text-left",
-      className)}
-    {...props}
-  />)
-DialogHeader.displayName = "DialogHeader"
+const DialogHeader = (
+    { className, ...props }: React.HTMLAttributes<HTMLDivElement>,
+) => (
+    <div
+	className={cn (
+	    'flex flex-col space-y-1.5 text-center md:text-left',
+	    className)}
+	{...props}/>)
+DialogHeader.displayName = 'DialogHeader'
 
-const DialogFooter = ({
-  className,
-  ...props
-}: React.HTMLAttributes<HTMLDivElement>) => (
-  <div
-    className={cn(
-      "flex flex-col-reverse sm:flex-row sm:justify-end sm:space-x-2",
-      className)}
-    {...props}
-  />)
-DialogFooter.displayName = "DialogFooter"
+const DialogFooter = (
+    { className, ...props }: React.HTMLAttributes<HTMLDivElement>,
+) => (
+    <div
+	className={cn (
+	    'flex flex-col-reverse md:flex-row md:justify-end md:space-x-2',
+	    className)}
+	{...props}/>)
+DialogFooter.displayName = 'DialogFooter'
 
 const DialogTitle = React.forwardRef<
-  React.ElementRef<typeof DialogPrimitive.Title>,
-  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Title>
->(({ className, ...props }, ref) => (
-  <DialogPrimitive.Title
-    ref={ref}
-    className={cn(
-      "text-lg font-semibold leading-none tracking-tight",
-      className)}
-    {...props}
-  />))
+    React.ElementRef<typeof DialogPrimitive.Title>,
+    React.ComponentPropsWithoutRef<typeof DialogPrimitive.Title>
+>(
+    ({ className, ...props }, ref) => (
+	<DialogPrimitive.Title
+	    ref={ref}
+	    className={cn (
+		'text-lg font-semibold leading-none tracking-tight',
+		className)}
+	    {...props}/>))
 DialogTitle.displayName = DialogPrimitive.Title.displayName
 
 const DialogDescription = React.forwardRef<
-  React.ElementRef<typeof DialogPrimitive.Description>,
-  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Description>
->(({ className, ...props }, ref) => (
-  <DialogPrimitive.Description
-    ref={ref}
-    className={cn("text-sm text-muted-foreground", className)}
-    {...props}
-  />))
+    React.ElementRef<typeof DialogPrimitive.Description>,
+    React.ComponentPropsWithoutRef<typeof DialogPrimitive.Description>
+>(
+    ({ className, ...props }, ref) => (
+	<DialogPrimitive.Description
+	    ref={ref}
+	    className={cn ('text-sm text-muted-foreground', className)}
+	    {...props}/>))
 DialogDescription.displayName = DialogPrimitive.Description.displayName
 
 export {
-  Dialog,
-  DialogPortal,
-  DialogOverlay,
-  DialogClose,
-  DialogTrigger,
-  DialogContent,
-  DialogHeader,
-  DialogFooter,
-  DialogTitle,
-  DialogDescription,
+    Dialog,
+    DialogPortal,
+    DialogOverlay,
+    DialogClose,
+    DialogTrigger,
+    DialogContent,
+    DialogHeader,
+    DialogFooter,
+    DialogTitle,
+    DialogDescription,
 }

frontend/src/lib/api.ts

@@ -8,6 +8,7 @@ import type { AxiosError, AxiosRequestConfig } from 'axios'
 type Opt = {
     params?:        AxiosRequestConfig['params']
     headers?:       Record<string, string>
+    signal?:        AbortSignal
     responseType?:  'blob' }
 
 const client = axios.create ({ baseURL: API_BASE_URL })

frontend/src/lib/postImportRows.test.ts

@@ -16,7 +16,7 @@ import { creatableImportRows,
 	 resultRowMessages,
 	 resultSummaryCounts,
 	 retryImportRow,
-	 reviewSummaryCounts } from '@/lib/postImportSession'
+	 reviewSummaryCounts } from '@/lib/postImportRows'
 import { buildPostImportRow } from '@/test/postImportFactories'
 
 describe ('post import row state', () => {
@@ -26,22 +26,26 @@ describe ('post import row state', () => {
       sourceRow: 2,
       skipReason: 'existing',
       existingPostId: 20 })
-    const invalid = buildPostImportRow ({
+    const manual = buildPostImportRow ({
       sourceRow: 3,
+      skipReason: 'manual' })
+    const invalid = buildPostImportRow ({
+      sourceRow: 4,
       status: 'error',
       validationErrors: { url: ['invalid'] } })
     const created = buildPostImportRow ({
-      sourceRow: 4,
+      sourceRow: 5,
       importStatus: 'created',
       createdPostId: 40 })
-    const rows = [ready, existing, invalid, created]
+    const rows = [ready, existing, manual, invalid, created]
 
-    expect (processableImportRows (rows)).toEqual ([ready, existing])
+    expect (processableImportRows (rows)).toEqual ([ready])
     expect (creatableImportRows (rows)).toEqual ([ready])
     expect (reviewSummaryCounts (rows)).toEqual ({
-      total: 4,
-      submittable: 1,
-      skipPlanned: 1 })
+      creatable: 1,
+      manualSkipped: 1,
+      existingSkipped: 1,
+      pendingOrError: 1 })
   })
 
   it ('preserves terminal rows while merging validation results', () => {
@@ -270,7 +274,7 @@ describe ('post import row state', () => {
           thumbnailBase: '',
           originalCreatedFrom: '',
           originalCreatedBefore: '',
-          duration: '2.5',
+          duration: '2',
           tags: 'edited-tag',
           parentPostIds: '' },
         true)
@@ -279,7 +283,7 @@ describe ('post import row state', () => {
     expect (nextRow.importErrors).toBeUndefined ()
     expect (nextRow.url).toBe ('https://example.com/edited')
     expect (nextRow.attributes.title).toBe ('edited title')
-    expect (nextRow.attributes.duration).toBe ('2.5')
+    expect (nextRow.attributes.duration).toBe ('2')
     expect (nextRow.attributes.tags).toBe ('edited-tag')
     expect (nextRow.provenance.title).toBe ('manual')
     expect (nextRow.provenance.url).toBe ('manual')

frontend/src/lib/postImportRows.ts

@@ -2,11 +2,41 @@ import type { PostImportEditableDraft,
 	      PostImportResultRow,
 	      PostImportRow } from '@/lib/postImportTypes'
 
-const hasSkipReason = (row: PostImportRow): boolean =>
+const THUMBNAIL_MISSING_WARNING = 'サムネールなし'
+
+export const hasThumbnailBaseValue = (value: unknown): boolean =>
+    typeof value === 'string' && value.trim () !== ''
+
+export const hasVideoTag = (value: unknown): boolean =>
+    typeof value === 'string'
+    && value.split (/\s+/).includes ('動画')
+
+export const isExistingSkipRow = (row: PostImportRow): boolean =>
     row.skipReason === 'existing'
 
+
+export const isManualSkipRow = (row: PostImportRow): boolean =>
+    row.skipReason === 'manual'
+
+
+const hasSkipReason = (row: PostImportRow): boolean =>
+    row.skipReason != null
+
+export const compactMessageRecord = (
+    messages: Record<string, string[]>,
+): Record<string, string[]> =>
+    Object.fromEntries (
+	Object.entries (messages).filter (([, values]) => values.length > 0))
+
+
+export const hasErrorMessages = (
+    messages: Record<string, string[]>,
+): boolean =>
+    Object.values (messages).some (values => values.length > 0)
+
+
 const hasValidationErrors = (row: PostImportRow): boolean =>
-    Object.keys (row.validationErrors ?? { }).length > 0
+    hasErrorMessages (row.validationErrors ?? { })
 
 const isRecoverableRow = (row: PostImportRow): boolean =>
     row.recoverable === true
@@ -15,9 +45,33 @@ const isRepairableImportStatus = (row: PostImportRow): boolean =>
     isRecoverableRow (row)
     && (row.importStatus === 'failed' || row.importStatus === 'pending')
 
+
+export const isNonRecoverableFailedRow = (row: PostImportRow): boolean =>
+    row.importStatus === 'failed' && row.recoverable !== true
+
+
+export const isTerminalRow = (row: PostImportRow): boolean =>
+    row.importStatus === 'created'
+    || row.importStatus === 'skipped'
+    || isNonRecoverableFailedRow (row)
+
+
+export const isCompletedReviewRow = (row: PostImportRow): boolean =>
+    row.importStatus === 'created'
+    || row.importStatus === 'skipped'
+    || hasSkipReason (row)
+
+
+export const validatableImportRows = (rows: PostImportRow[]): PostImportRow[] =>
+    rows.filter (row => !(hasSkipReason (row)) && !(isTerminalRow (row)))
+
 const buildResetSnapshot = (row: PostImportRow) => ({
     url: row.url,
     attributes: { ...row.attributes },
+    displayTags: row.displayTags?.map (tag => ({
+	name: tag.name,
+	category: tag.category,
+	sectionLiterals: tag.sectionLiterals == null ? undefined : [...tag.sectionLiterals] })) ?? [],
     provenance: { ...row.provenance },
     tagSources: {
 	automatic: row.tagSources?.automatic ?? '',
@@ -27,9 +81,34 @@ const buildResetSnapshot = (row: PostImportRow) => ({
     baseWarnings: [...row.baseWarnings],
     metadataUrl: row.metadataUrl })
 
+const deduped = (values: string[]): string[] =>
+    [...new Set (values)]
+
+
+const thumbnailWarnings = (row: PostImportRow): string[] => {
+    const current = row.fieldWarnings.thumbnailBase ?? []
+    const others = current.filter (message => message !== THUMBNAIL_MISSING_WARNING)
+    return hasThumbnailBaseValue (row.attributes.thumbnailBase) || row.thumbnailFile != null
+        ? others
+        : deduped ([...others, THUMBNAIL_MISSING_WARNING])
+}
+
+
+export const applyThumbnailWarning = (row: PostImportRow): PostImportRow => ({
+    ...row,
+    fieldWarnings: compactMessageRecord ({
+	...row.fieldWarnings,
+	thumbnailBase: thumbnailWarnings (row) }) })
+
+
+export const applyThumbnailWarnings = (rows: PostImportRow[]): PostImportRow[] =>
+    rows.map (row => applyThumbnailWarning (row))
+
 
 export const processableImportRows = (rows: PostImportRow[]): PostImportRow[] =>
-    rows.filter (row => {
+    validatableImportRows (rows).filter (row => {
+      if (row.status === 'pending')
+        return false
       if (row.importStatus === 'created')
         return false
       if (row.importStatus === 'skipped')
@@ -46,13 +125,12 @@ export const creatableImportRows = (rows: PostImportRow[]): PostImportRow[] =>
 
 
 export const reviewSummaryCounts = (rows: PostImportRow[]) => ({
-    total: rows.length,
-    submittable: rows.filter (row =>
-        creatableImportRows ([row]).length > 0
-        && !(hasValidationErrors (row))).length,
-    skipPlanned: rows.filter (row =>
-        processableImportRows ([row]).length > 0
-        && hasSkipReason (row)).length })
+    creatable: rows.filter (row => creatableImportRows ([row]).length > 0).length,
+    manualSkipped: rows.filter (row => isManualSkipRow (row)).length,
+    existingSkipped: rows.filter (row => isExistingSkipRow (row)).length,
+    pendingOrError: rows.filter (row =>
+        !(isCompletedReviewRow (row))
+        && creatableImportRows ([row]).length === 0).length })
 
 
 export const resultSummaryCounts = (rows: PostImportRow[]) =>
@@ -85,19 +163,22 @@ export const resultRepairMode = (
 
 
 export const canEditReviewRow = (row: PostImportRow): boolean =>
-    !(row.importStatus === 'created'
+    !(hasSkipReason (row)
+      || row.importStatus === 'created'
       || row.importStatus === 'skipped'
       || (row.importStatus === 'failed' && row.recoverable !== true))
 
 
 export const canEditResultRow = (row: PostImportRow): boolean =>
-    row.recoverable === true
+    row.skipReason == null
+    && row.recoverable === true
     && (row.importStatus === 'failed'
         || (row.importStatus === 'pending' && hasValidationErrors (row)))
 
 
 export const canRetryResultRow = (row: PostImportRow): boolean =>
-    row.recoverable === true
+    row.skipReason == null
+    && row.recoverable === true
     && (row.importStatus === 'failed'
         || (row.importStatus === 'pending' && !(hasValidationErrors (row))))
 
@@ -113,6 +194,14 @@ export const resultRowWarnings = (row: PostImportRow): string[] =>
         ...Object.values (row.fieldWarnings ?? { }).flat (),
         ...row.baseWarnings])]
 
+
+const isManualChange = (
+    current: unknown,
+    next:    string,
+): boolean =>
+    next !== String (current ?? '')
+
+
 export const buildNextEditedRow = (
     editingRow:  PostImportRow,
     draft:       PostImportEditableDraft,
@@ -133,12 +222,12 @@ export const buildNextEditedRow = (
     draftFields.forEach (([field, value]) => {
 	nextAttributes[field] = value
 	nextProvenance[field] =
-	    value !== String (editingRow.attributes[field] ?? '')
+	    isManualChange (editingRow.attributes[field], value)
 	    ? 'manual'
 	    : (editingRow.provenance[field] ?? 'automatic')
     })
     nextAttributes.tags = draft.tags
-    if (draft.tags !== String (editingRow.attributes.tags ?? ''))
+    if (isManualChange (editingRow.attributes.tags, draft.tags))
       {
 	nextProvenance.tags = 'manual'
 	nextTagSources.manual = draft.tags
@@ -153,6 +242,12 @@ export const buildNextEditedRow = (
 	...editingRow,
 	url: draft.url,
 	attributes: nextAttributes,
+	displayTags:
+	    editingRow.displayTags?.map (tag => ({
+		name: tag.name,
+		category: tag.category,
+		sectionLiterals: tag.sectionLiterals == null ? undefined : [...tag.sectionLiterals] })),
+	thumbnailFile: draft.thumbnailFile,
 	provenance: {
 	    ...nextProvenance,
 	    url: urlChanged ? 'manual' : (editingRow.provenance.url ?? 'manual') },
@@ -212,7 +307,7 @@ export const mergeValidatedImportRows = (
         return previous
 
       const fieldWarnings =
-          Object.keys (row.fieldWarnings).length > 0 || row.metadataUrl !== previous.metadataUrl
+          hasErrorMessages (row.fieldWarnings) || row.metadataUrl !== previous.metadataUrl
           ? { ...row.fieldWarnings }
           : { ...previous.fieldWarnings }
       for (const [field, origin] of Object.entries (row.provenance))
@@ -225,10 +320,17 @@ export const mergeValidatedImportRows = (
           ...previous,
           url: row.url,
           attributes: row.attributes,
+          displayTags:
+              row.displayTags?.map (tag => ({
+                  name: tag.name,
+                  category: tag.category,
+                  sectionLiterals:
+                      tag.sectionLiterals == null ? undefined : [...tag.sectionLiterals] })),
           provenance: row.provenance,
           tagSources: row.tagSources,
           skipReason: row.skipReason,
           existingPostId: row.existingPostId,
+          existingPost: row.existingPost,
           fieldWarnings,
           baseWarnings:
               row.baseWarnings.length > 0 || row.metadataUrl !== previous.metadataUrl
@@ -265,9 +367,11 @@ export const mergeImportResults = (
               skipReason: undefined,
               createdPostId: result.post.id,
               existingPostId: undefined,
-              fieldWarnings: result.fieldWarnings ?? row.fieldWarnings,
+              existingPost: undefined,
+              fieldWarnings: compactMessageRecord (
+		  result.fieldWarnings ?? row.fieldWarnings),
               baseWarnings: result.baseWarnings ?? row.baseWarnings,
-              importErrors: result.errors }
+              importErrors: compactMessageRecord (result.errors ?? { }) }
         case 'skipped':
           return {
               ...row,
@@ -276,9 +380,11 @@ export const mergeImportResults = (
               skipReason: 'existing',
               createdPostId: undefined,
               existingPostId: result.existingPostId,
-              fieldWarnings: result.fieldWarnings ?? row.fieldWarnings,
+              existingPost: result.existingPost ?? row.existingPost,
+              fieldWarnings: compactMessageRecord (
+		  result.fieldWarnings ?? row.fieldWarnings),
               baseWarnings: result.baseWarnings ?? row.baseWarnings,
-              importErrors: result.errors }
+              importErrors: compactMessageRecord (result.errors ?? { }) }
         case 'failed':
           return {
               ...row,
@@ -287,9 +393,11 @@ export const mergeImportResults = (
               skipReason: undefined,
               createdPostId: undefined,
               existingPostId: undefined,
-              fieldWarnings: result.fieldWarnings ?? row.fieldWarnings,
+              existingPost: undefined,
+              fieldWarnings: compactMessageRecord (
+		  result.fieldWarnings ?? row.fieldWarnings),
               baseWarnings: result.baseWarnings ?? row.baseWarnings,
-              importErrors: result.errors }
+              importErrors: compactMessageRecord (result.errors ?? { }) }
         }
     })
 }
@@ -307,6 +415,7 @@ export const retryImportRow = (
         : row)
 
 export const initialisePreviewRows = (rows: PostImportRow[]): PostImportRow[] =>
-    rows.map (row => ({
-        ...row,
-        resetSnapshot: buildResetSnapshot (row) }))
+    applyThumbnailWarnings (
+	rows.map (row => ({
+	    ...row,
+	    resetSnapshot: buildResetSnapshot (row) })))

frontend/src/lib/postImportSession.ts

@@ -1,4 +0,0 @@
-export * from '@/lib/postImportTypes'
-export * from '@/lib/postImportStorage'
-export * from '@/lib/postImportSourceValidation'
-export * from '@/lib/postImportRows'

frontend/src/lib/postImportSourceValidation.test.ts

@@ -1,6 +1,9 @@
 import { describe, expect, it } from 'vitest'
 
-import { countImportSourceLines, validateImportSource } from '@/lib/postImportSession'
+import {
+    countImportSourceLines,
+    validateImportSource,
+} from '@/lib/postImportSourceValidation'
 
 describe ('post import source validation', () => {
   it ('counts trimmed non-empty CRLF and LF rows', () => {

frontend/src/lib/postImportSourceValidation.ts

@@ -12,23 +12,14 @@ const bytesize = (value: string): number =>
     new TextEncoder ().encode (value).length
 
 
-const normaliseImportUrl = (value: string): string | null => {
+const parseImportUrl = (value: string): URL | null => {
     const trimmed = value.trim ()
     if (!(trimmed))
       return null
 
     try
     {
-      const url = new URL (trimmed)
-      if (!(url.protocol === 'http:' || url.protocol === 'https:'))
-        return null
-      if (!(url.host))
-        return null
-
-      url.hostname = url.hostname.toLowerCase ()
-      if (url.pathname.endsWith ('/'))
-        url.pathname = url.pathname.replace (/\/+$/, '')
-      return url.toString ()
+      return new URL (trimmed)
     }
     catch
     {
@@ -37,12 +28,23 @@ const normaliseImportUrl = (value: string): string | null => {
 }
 
 
-export const countImportSourceLines = (source: string): number =>
+const normaliseImportUrl = (url: URL): string => {
+  url.hostname = url.hostname.toLowerCase ()
+  if (url.pathname.endsWith ('/'))
+    url.pathname = url.pathname.replace (/\/+$/, '')
+  return url.toString ()
+}
+
+
+export const extractImportSourceUrls = (source: string): string[] =>
     source
         .split (/\r\n|\n|\r/)
         .map (line => line.trim ())
         .filter (line => line !== '')
-        .length
+
+
+export const countImportSourceLines = (source: string): number =>
+    extractImportSourceUrls (source).length
 
 
 export const validateImportSource = (
@@ -61,7 +63,6 @@ export const validateImportSource = (
       ++count
       const sourceRow = index + 1
       const displayUrl = truncateUrl (value)
-      const normalised = normaliseImportUrl (value)
       if (count > MAX_ROWS)
         {
           issues.push ({
@@ -70,14 +71,6 @@ export const validateImportSource = (
               url: displayUrl })
           return
         }
-      if (!(value.startsWith ('http://') || value.startsWith ('https://')))
-        {
-          issues.push ({
-              sourceRow,
-              message: 'HTTP または HTTPS の URL ではありません．',
-              url: displayUrl })
-          return
-        }
       if (bytesize (value) > MAX_URL_BYTES)
         {
           issues.push ({
@@ -86,7 +79,8 @@ export const validateImportSource = (
               url: displayUrl })
           return
         }
-      if (normalised == null)
+      const parsed = parseImportUrl (value)
+      if (parsed == null)
         {
           issues.push ({
               sourceRow,
@@ -94,6 +88,23 @@ export const validateImportSource = (
               url: displayUrl })
           return
         }
+      if (!(parsed.protocol === 'http:' || parsed.protocol === 'https:'))
+        {
+          issues.push ({
+              sourceRow,
+              message: 'HTTP または HTTPS の URL ではありません．',
+              url: displayUrl })
+          return
+        }
+      if (!(parsed.host))
+        {
+          issues.push ({
+              sourceRow,
+              message: 'URL の形式が不正です．',
+              url: displayUrl })
+          return
+        }
+      const normalised = normaliseImportUrl (parsed)
       const duplicateRow = seen.get (normalised)
       if (duplicateRow != null)
         {

frontend/src/lib/postImportStorage.test.ts

@@ -1,117 +1,31 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
-import { cleanupExpiredPostImportSessions,
-	 clearPostImportSourceDraft,
-	 loadPostImportSession,
-	 loadPostImportSourceDraft,
-	 savePostImportSession,
-	 savePostImportSourceDraft } from '@/lib/postImportSession'
-import { buildPostImportRow } from '@/test/postImportFactories'
+import {
+    clearPostImportSourceDraft,
+    loadPostImportSourceDraft,
+    savePostImportSourceDraft,
+} from '@/lib/postImportStorage'
 
-describe ('post import storage', () => {
+describe ('post import source draft storage', () => {
   beforeEach (() => {
     sessionStorage.clear ()
-    vi.useRealTimers ()
+    vi.restoreAllMocks ()
   })
 
-  it ('round-trips a valid session and source draft', () => {
-    const row = buildPostImportRow ({
-      attributes: { duration: '2.5' },
-      recoverable: true,
-      importStatus: 'pending',
-      validationErrors: { title: ['invalid'] } })
-    const skipped = buildPostImportRow ({
-      importStatus: 'skipped',
-      skipReason: 'existing',
-      existingPostId: 10 })
-
-    expect (savePostImportSession ('session', {
-      source: skipped.url,
-      rows: [row, skipped],
-      repairMode: 'all' })).toBe (true)
-    expect (loadPostImportSession ('session')).toMatchObject ({
-      version: 2,
-      source: skipped.url,
-      rows: [{
-	attributes: { duration: '2.5' },
-	recoverable: true,
-	importStatus: 'pending' },
-	      {
-	importStatus: 'skipped',
-	skipReason: 'existing',
-	existingPostId: 10 }] })
-
+  it ('round-trips and clears the URL list source draft', () => {
     expect (savePostImportSourceDraft ('https://example.com')).toBe (true)
-    expect (loadPostImportSourceDraft ()).toEqual ({ source: 'https://example.com' })
+    expect (loadPostImportSourceDraft ()).toEqual ({
+	source: 'https://example.com' })
+
     clearPostImportSourceDraft ()
+
     expect (loadPostImportSourceDraft ()).toEqual ({ source: '' })
   })
 
-  it ('rejects inconsistent post IDs and terminal statuses', () => {
-    const session = {
-      version: 2,
-      savedAt: new Date ().toISOString (),
-      source: '',
-      repairMode: 'all',
-      rows: [buildPostImportRow ()] }
-    const invalidRows = [
-      { ...session.rows[0], skipReason: 'existing', existingPostId: undefined },
-      { ...session.rows[0], existingPostId: 2, skipReason: undefined },
-      { ...session.rows[0], importStatus: 'created', createdPostId: undefined },
-      { ...session.rows[0], importStatus: 'failed', createdPostId: 3 },
-      { ...session.rows[0], importStatus: 'created', recoverable: true },
-      { ...session.rows[0], importStatus: 'skipped', recoverable: true },
-      { ...session.rows[0], recoverable: true }]
+  it ('ignores malformed stored drafts', () => {
+    sessionStorage.setItem ('post-import-source-draft', '{')
 
-    for (const [index, row] of invalidRows.entries ())
-      {
-	sessionStorage.setItem (`post-import-session:invalid-${ index }`, JSON.stringify ({
-	  ...session,
-	  rows: [row] }))
-	expect (loadPostImportSession (`invalid-${ index }`)).toBeNull ()
-      }
-  })
-
-  it ('rejects invalid attribute, provenance, tag-source, and snapshot data', () => {
-    const row = buildPostImportRow ()
-    const invalidRows = [
-      { ...row, attributes: { title: [] } },
-      { ...row, attributes: { unknown: 'value' } },
-      { ...row, provenance: { title: 'mapped' } },
-      { ...row, tagSources: { mapped: 'tag' } },
-      { ...row, resetSnapshot: { ...row.resetSnapshot,
-	fieldWarnings: { title: 'warning' } } }]
-
-    invalidRows.forEach ((invalidRow, index) => {
-      sessionStorage.setItem (`post-import-session:shape-${ index }`, JSON.stringify ({
-	version: 2,
-	savedAt: new Date ().toISOString (),
-	source: '',
-	rows: [invalidRow],
-	repairMode: 'all' }))
-      expect (loadPostImportSession (`shape-${ index }`)).toBeNull ()
-    })
-  })
-
-  it ('removes expired and malformed sessions without touching current sessions', () => {
-    const current = {
-      version: 2,
-      savedAt: new Date ().toISOString (),
-      source: '',
-      rows: [buildPostImportRow ()],
-      repairMode: 'all' }
-    const expired = {
-      ...current,
-      savedAt: new Date (Date.now () - 25 * 60 * 60 * 1000).toISOString () }
-    sessionStorage.setItem ('post-import-session:current', JSON.stringify (current))
-    sessionStorage.setItem ('post-import-session:expired', JSON.stringify (expired))
-    sessionStorage.setItem ('post-import-session:malformed', '{')
-
-    cleanupExpiredPostImportSessions ()
-
-    expect (sessionStorage.getItem ('post-import-session:current')).not.toBeNull ()
-    expect (sessionStorage.getItem ('post-import-session:expired')).toBeNull ()
-    expect (sessionStorage.getItem ('post-import-session:malformed')).toBeNull ()
+    expect (loadPostImportSourceDraft ()).toEqual ({ source: '' })
   })
 
   it ('reports storage access failures without throwing', () => {

frontend/src/lib/postImportStorage.ts

@@ -1,52 +1,24 @@
-import type { PostImportOrigin,
-	      PostImportResetSnapshot,
-	      PostImportRow,
-	      PostImportSession,
-	      PostImportStatus,
-	      PostImportSkipReason,
-	      StorageErrorHandler } from '@/lib/postImportTypes'
+import type { StorageErrorHandler } from '@/lib/postImportTypes'
 
-const SESSION_VERSION = 2
-const SESSION_PREFIX = 'post-import-session:'
 const SOURCE_DRAFT_KEY = 'post-import-source-draft'
-const SESSION_MAX_AGE_MS = 24 * 60 * 60 * 1000
-const ATTRIBUTE_KEYS = [
-    'title',
-    'thumbnailBase',
-    'originalCreatedFrom',
-    'originalCreatedBefore',
-    'duration',
-    'videoMs',
-    'tags',
-    'parentPostIds'] as const
-const PROVENANCE_KEYS = [...ATTRIBUTE_KEYS, 'url'] as const
-const TAG_SOURCE_KEYS = ['automatic', 'manual'] as const
-const WARNING_KEYS = [...ATTRIBUTE_KEYS, 'url'] as const
-
-
-const isPlainObject = (value: unknown): value is Record<string, unknown> =>
-    typeof value === 'object' && value != null && !(Array.isArray (value))
-
-
-const sessionKey = (sessionId: string): string => `${ SESSION_PREFIX }${ sessionId }`
 
 
 const readStorage = (
     key:       string,
     onError?:  StorageErrorHandler,
 ): string | null => {
-    if (typeof window === 'undefined')
-      return null
+  if (typeof window === 'undefined')
+    return null
 
-    try
-    {
-      return sessionStorage.getItem (key)
-    }
-    catch
-    {
-      onError?.('保存済みデータを読み込めませんでした．')
-      return null
-    }
+  try
+  {
+    return sessionStorage.getItem (key)
+  }
+  catch
+  {
+    onError?.('保存済みデータを読み込めませんでした．')
+    return null
+  }
 }
 
 
@@ -55,19 +27,19 @@ const writeStorage = (
     value:     string,
     onError?:  StorageErrorHandler,
 ): boolean => {
-    if (typeof window === 'undefined')
-      return false
+  if (typeof window === 'undefined')
+    return false
 
-    try
-    {
-      sessionStorage.setItem (key, value)
-      return true
-    }
-    catch
-    {
-      onError?.('ブラウザへ保存できませんでした．')
-      return false
-    }
+  try
+  {
+    sessionStorage.setItem (key, value)
+    return true
+  }
+  catch
+  {
+    onError?.('ブラウザへ保存できませんでした．')
+    return false
+  }
 }
 
 
@@ -75,281 +47,36 @@ const removeStorage = (
     key:       string,
     onError?:  StorageErrorHandler,
 ) => {
-    if (typeof window === 'undefined')
-      return
+  if (typeof window === 'undefined')
+    return
 
-    try
-    {
-      sessionStorage.removeItem (key)
-    }
-    catch
-    {
-      onError?.('保存済みデータを削除できませんでした．')
-    }
-}
-
-
-const ensureStringListRecord = (value: unknown): Record<string, string[]> | null => {
-    if (!(isPlainObject (value)))
-      return null
-
-    const result: Record<string, string[]> = { }
-    for (const [key, entry] of Object.entries (value))
-      {
-        if (!(Array.isArray (entry)) || !(entry.every (item => typeof item === 'string')))
-          return null
-        result[key] = entry
-      }
-    return result
-}
-
-
-const isValidStatus = (
-    value: unknown,
-): value is PostImportRow['status'] =>
-    value === 'ready' || value === 'warning' || value === 'error'
-
-
-const isValidImportStatus = (
-    value: unknown,
-): value is PostImportStatus =>
-    value === 'pending'
-    || value === 'created'
-    || value === 'skipped'
-    || value === 'failed'
-
-
-const isValidOrigin = (
-    value: unknown,
-): value is PostImportOrigin =>
-    value === 'automatic' || value === 'manual'
-
-
-const isValidSkipReason = (
-    value: unknown,
-): value is PostImportSkipReason =>
-    value === 'existing'
-
-const isPositiveInteger = (value: unknown): value is number =>
-    Number.isInteger (value) && Number (value) > 0
-
-const hasOnlyKeys = (
-    value:        Record<string, unknown>,
-    allowedKeys:  readonly string[],
-): boolean =>
-    Object.keys (value).every (key => allowedKeys.includes (key))
-
-const sanitiseResetSnapshot = (value: unknown): PostImportResetSnapshot | null => {
-    if (!(isPlainObject (value)))
-      return null
-    if (typeof value.url !== 'string')
-      return null
-    if (!(isPlainObject (value.attributes)))
-      return null
-    if (!(hasOnlyKeys (value.attributes, ATTRIBUTE_KEYS)))
-      return null
-    if (!(Object.values (value.attributes).every (entry =>
-        typeof entry === 'string' || typeof entry === 'number')))
-      return null
-    if (!(isPlainObject (value.provenance)))
-      return null
-    if (!(hasOnlyKeys (value.provenance, PROVENANCE_KEYS)))
-      return null
-    if (!(Object.values (value.provenance).every (origin => isValidOrigin (origin))))
-      return null
-    if (!(isPlainObject (value.tagSources)))
-      return null
-    if (!(hasOnlyKeys (value.tagSources, TAG_SOURCE_KEYS)))
-      return null
-    if (!(Object.values (value.tagSources).every (entry => typeof entry === 'string')))
-      return null
-    const fieldWarnings = ensureStringListRecord (value.fieldWarnings)
-    if (fieldWarnings == null)
-      return null
-    if (!(hasOnlyKeys (fieldWarnings, WARNING_KEYS)))
-      return null
-    if (!(Array.isArray (value.baseWarnings))
-        || !(value.baseWarnings.every (warning => typeof warning === 'string')))
-      return null
-    if (value.metadataUrl != null && typeof value.metadataUrl !== 'string')
-      return null
-
-    return {
-        url: value.url,
-        attributes: value.attributes as Record<string, string | number>,
-        provenance: value.provenance as Record<string, PostImportOrigin>,
-        tagSources: value.tagSources as Record<PostImportOrigin, string>,
-        fieldWarnings,
-        baseWarnings: value.baseWarnings,
-        metadataUrl: value.metadataUrl as string | undefined }
-}
-
-
-const sanitiseRow = (value: unknown): PostImportRow | null => {
-    if (!(isPlainObject (value)))
-      return null
-    if (!(Number.isInteger (value.sourceRow)) || Number (value.sourceRow) <= 0)
-      return null
-    if (typeof value.url !== 'string')
-      return null
-    if (!(isPlainObject (value.attributes)))
-      return null
-    if (!(isPlainObject (value.provenance)))
-      return null
-    if (!(isValidStatus (value.status)))
-      return null
-    if (value.importStatus != null && !(isValidImportStatus (value.importStatus)))
-      return null
-    if (value.skipReason != null && !(isValidSkipReason (value.skipReason)))
-      return null
-    if (value.recoverable != null && value.recoverable !== true)
-      return null
-    if (value.skipReason === 'existing' && !(isPositiveInteger (value.existingPostId)))
-      return null
-    if (value.skipReason !== 'existing' && value.existingPostId != null)
-      return null
-    if (value.importStatus === 'created' && !(isPositiveInteger (value.createdPostId)))
-      return null
-    if (value.importStatus !== 'created' && value.createdPostId != null)
-      return null
-    if (value.recoverable === true
-        && value.importStatus !== 'failed'
-        && value.importStatus !== 'pending')
-      return null
-    if ((value.importStatus === 'created' || value.importStatus === 'skipped')
-        && value.recoverable != null)
-      return null
-
-    const validationErrors = ensureStringListRecord (value.validationErrors)
-    const fieldWarnings = ensureStringListRecord (value.fieldWarnings)
-    const resetSnapshot = sanitiseResetSnapshot (value.resetSnapshot)
-    if (validationErrors == null || fieldWarnings == null)
-      return null
-    if (resetSnapshot == null)
-      return null
-
-    const importErrors =
-        value.importErrors == null
-        ? undefined
-        : ensureStringListRecord (value.importErrors)
-    if (importErrors === null)
-      return null
-    if (!(Array.isArray (value.baseWarnings))
-        || !(value.baseWarnings.every (warning => typeof warning === 'string')))
-      return null
-
-    const provenanceEntries = Object.entries (value.provenance)
-    if (!(hasOnlyKeys (value.attributes, ATTRIBUTE_KEYS)))
-      return null
-    if (!(Object.values (value.attributes).every (entry =>
-        typeof entry === 'string' || typeof entry === 'number')))
-      return null
-    if (!(hasOnlyKeys (value.provenance, PROVENANCE_KEYS)))
-      return null
-    if (!(provenanceEntries.every (([, origin]) => isValidOrigin (origin))))
-      return null
-
-    if (value.tagSources != null)
-      {
-        if (!(isPlainObject (value.tagSources)))
-          return null
-        if (!(hasOnlyKeys (value.tagSources, TAG_SOURCE_KEYS)))
-          return null
-        if (!(Object.values (value.tagSources).every (entry => typeof entry === 'string')))
-          return null
-      }
-
-    return {
-        sourceRow: Number (value.sourceRow),
-        url: value.url,
-        attributes: value.attributes as Record<string, string | number>,
-        fieldWarnings,
-        baseWarnings: value.baseWarnings,
-        validationErrors,
-        importErrors,
-        provenance: value.provenance as Record<string, PostImportOrigin>,
-        tagSources: value.tagSources as Record<PostImportOrigin, string> | undefined,
-        status: value.status,
-        skipReason: value.skipReason ?? undefined,
-        existingPostId:
-            isPositiveInteger (value.existingPostId) ? Number (value.existingPostId) : undefined,
-        metadataUrl: typeof value.metadataUrl === 'string' ? value.metadataUrl : undefined,
-        resetSnapshot,
-        createdPostId:
-            isPositiveInteger (value.createdPostId) ? Number (value.createdPostId) : undefined,
-        importStatus: value.importStatus ?? undefined,
-        recoverable: value.recoverable === true ? true : undefined }
-}
-
-
-const isExpiredSession = (savedAt: string): boolean => {
-    const value = Date.parse (savedAt)
-    return Number.isNaN (value) || Date.now () - value > SESSION_MAX_AGE_MS
-}
-
-
-export const createPostImportSessionId = (): string =>
-    typeof crypto !== 'undefined' && 'randomUUID' in crypto
-    ? crypto.randomUUID ()
-    : `${ Date.now () }-${ Math.random ().toString (36).slice (2) }`
-
-
-export const cleanupExpiredPostImportSessions = (
-    onError?: StorageErrorHandler,
-) => {
-    if (typeof window === 'undefined')
-      return
-
-    try
-    {
-      for (let i = 0; i < sessionStorage.length; ++i)
-        {
-          const key = sessionStorage.key (i)
-          if (key == null || !(key.startsWith (SESSION_PREFIX)))
-            continue
-
-          const raw = sessionStorage.getItem (key)
-          if (raw == null)
-            continue
-          try
-          {
-            const value = JSON.parse (raw) as { savedAt?: string }
-            if (typeof value.savedAt !== 'string' || isExpiredSession (value.savedAt))
-              {
-                sessionStorage.removeItem (key)
-                --i
-              }
-          }
-          catch
-          {
-            sessionStorage.removeItem (key)
-            --i
-          }
-        }
-    }
-    catch
-    {
-      onError?.('保存済みデータを整理できませんでした．')
-    }
+  try
+  {
+    sessionStorage.removeItem (key)
+  }
+  catch
+  {
+    onError?.('保存済みデータを削除できませんでした．')
+  }
 }
 
 
 export const loadPostImportSourceDraft = (
     onError?: StorageErrorHandler,
 ): { source: string } => {
-    const raw = readStorage (SOURCE_DRAFT_KEY, onError)
-    if (raw == null)
-      return { source: '' }
+  const raw = readStorage (SOURCE_DRAFT_KEY, onError)
+  if (raw == null)
+    return { source: '' }
 
-    try
-    {
-      const value = JSON.parse (raw) as { source?: string }
-      return { source: typeof value.source === 'string' ? value.source : '' }
-    }
-    catch
-    {
-      return { source: '' }
-    }
+  try
+  {
+    const value = JSON.parse (raw) as { source?: string }
+    return { source: typeof value.source === 'string' ? value.source : '' }
+  }
+  catch
+  {
+    return { source: '' }
+  }
 }
 
 
@@ -363,56 +90,5 @@ export const savePostImportSourceDraft = (
 export const clearPostImportSourceDraft = (
     onError?: StorageErrorHandler,
 ) => {
-    removeStorage (SOURCE_DRAFT_KEY, onError)
-}
-
-
-export const savePostImportSession = (
-    sessionId: string,
-    session:   Omit<PostImportSession, 'version' | 'savedAt'>,
-    onError?:  StorageErrorHandler,
-): boolean =>
-    writeStorage (
-        sessionKey (sessionId),
-        JSON.stringify ({
-            ...session,
-            version: SESSION_VERSION,
-            savedAt: new Date ().toISOString () }),
-        onError)
-
-
-export const loadPostImportSession = (
-    sessionId: string,
-    onError?: StorageErrorHandler,
-): PostImportSession | null => {
-    const raw = readStorage (sessionKey (sessionId), onError)
-    if (raw == null)
-      return null
-
-    try
-    {
-      const value = JSON.parse (raw) as Partial<PostImportSession>
-      if (value.version !== SESSION_VERSION || !(Array.isArray (value.rows)))
-        return null
-      if (typeof value.savedAt !== 'string' || isExpiredSession (value.savedAt))
-        {
-          removeStorage (sessionKey (sessionId), onError)
-          return null
-        }
-
-      const rows = value.rows.map (sanitiseRow)
-      if (rows.some (row => row == null))
-        return null
-
-      return {
-          version: SESSION_VERSION,
-          savedAt: value.savedAt,
-          source: typeof value.source === 'string' ? value.source : '',
-          rows: rows as PostImportRow[],
-          repairMode: value.repairMode === 'failed' ? 'failed' : 'all' }
-    }
-    catch
-    {
-      return null
-    }
+  removeStorage (SOURCE_DRAFT_KEY, onError)
 }

frontend/src/lib/postImportTypes.ts

@@ -1,3 +1,5 @@
+import type { Category } from '@/types'
+
 export type PostImportOrigin = 'automatic' | 'manual'
 export type PostImportRepairMode = 'all' | 'failed'
 export type PostImportStatus =
@@ -5,19 +7,32 @@ export type PostImportStatus =
     | 'created'
     | 'skipped'
     | 'failed'
-export type PostImportSkipReason = 'existing'
+export type PostImportSkipReason = 'existing' | 'manual'
 export type PostImportResultStatus = 'created' | 'skipped' | 'failed'
 export type PostImportAttributeValue = string | number
 
+export type PostImportDisplayTag = {
+    name:            string
+    category:        Category
+    sectionLiterals?: string[] }
+
 export type PostImportResetSnapshot = {
     url:         string
     attributes:  Record<string, PostImportAttributeValue>
+    displayTags: PostImportDisplayTag[]
     provenance:  Record<string, PostImportOrigin>
     tagSources:  Record<PostImportOrigin, string>
     fieldWarnings: Record<string, string[]>
     baseWarnings: string[]
     metadataUrl?: string }
 
+export type PostImportExistingPost = {
+    id:            number
+    title:         string
+    url:           string
+    thumbnail?:    string | null
+    thumbnailBase?: string | null }
+
 export type PostImportRow = {
     sourceRow:         number
     url:               string
@@ -28,14 +43,17 @@ export type PostImportRow = {
     importErrors?:     Record<string, string[]>
     provenance:        Record<string, PostImportOrigin>
     tagSources?:       Record<PostImportOrigin, string>
-    status:            'ready' | 'warning' | 'error'
+    status:            'pending' | 'ready' | 'warning' | 'error'
     skipReason?:       PostImportSkipReason
     existingPostId?:   number
+    existingPost?:     PostImportExistingPost
     metadataUrl?:      string
+    displayTags?:      PostImportDisplayTag[]
     resetSnapshot:     PostImportResetSnapshot
     createdPostId?:    number
     importStatus?:     PostImportStatus
-    recoverable?:      boolean }
+    recoverable?:      boolean
+    thumbnailFile?:    File }
 
 export type PostImportResultRow =
     | {
@@ -49,6 +67,7 @@ export type PostImportResultRow =
 	sourceRow:      number
 	status:         'skipped'
 	existingPostId: number
+	existingPost?:  PostImportExistingPost
 	fieldWarnings?: Record<string, string[]>
 	baseWarnings?:  string[]
 	errors?:        Record<string, string[]> }
@@ -60,13 +79,6 @@ export type PostImportResultRow =
 	errors?:   Record<string, string[]>
 	recoverable?: boolean }
 
-export type PostImportSession = {
-    version:    number
-    savedAt:    string
-    source:     string
-    rows:       PostImportRow[]
-    repairMode: PostImportRepairMode }
-
 export type PostImportSourceIssue = {
     sourceRow: number
     message:   string
@@ -80,6 +92,7 @@ export type PostImportEditableDraft = {
     originalCreatedBefore: string
     duration:              string
     tags:                  string
-    parentPostIds:         string }
+    parentPostIds:         string
+    thumbnailFile?:        File }
 
 export type StorageErrorHandler = (message: string) => void

frontend/src/lib/postNewQueryState.test.ts

@@ -0,0 +1,43 @@
+import { describe, expect, it } from 'vitest'
+
+import {
+    buildPostNewReviewPath,
+    hasPostNewReviewState,
+    isPostNewReviewPathWithinLimit,
+    parsePostNewReviewUrls,
+    postNewReviewPathByteLength,
+} from '@/lib/postNewQueryState'
+
+describe ('post new review URL state', () => {
+  it ('encodes each URL separately and preserves literal plus signs', () => {
+    const urls = [
+	'https://example.com/one+a',
+	'https://example.com/two?value=b+c']
+
+    const path = buildPostNewReviewPath (urls)
+
+    expect (path).toBe (
+	'/posts/new?urls=https%3A%2F%2Fexample.com%2Fone%2Ba'
+	+ '+https%3A%2F%2Fexample.com%2Ftwo%3Fvalue%3Db%2Bc')
+    expect (parsePostNewReviewUrls (path.slice ('/posts/new'.length))).toEqual (urls)
+  })
+
+  it ('uses only the raw urls parameter as review state', () => {
+    expect (hasPostNewReviewState ('?session_id=old&meta=old')).toBe (false)
+    expect (hasPostNewReviewState ('?unknown=value&urls=')).toBe (true)
+    expect (parsePostNewReviewUrls ('?unknown=value&urls=one+two&meta=old'))
+	.toEqual (['one', 'two'])
+  })
+
+  it ('allows at most a 6 143 byte request target', () => {
+    const baseUrl = 'https://example.com/'
+    const baseLength = postNewReviewPathByteLength ([baseUrl])
+    const allowed = `${ baseUrl }${ 'a'.repeat (6_143 - baseLength) }`
+    const denied = `${ allowed }a`
+
+    expect (postNewReviewPathByteLength ([allowed])).toBe (6_143)
+    expect (isPostNewReviewPathWithinLimit ([allowed])).toBe (true)
+    expect (postNewReviewPathByteLength ([denied])).toBe (6_144)
+    expect (isPostNewReviewPathWithinLimit ([denied])).toBe (false)
+  })
+})

frontend/src/lib/postNewQueryState.ts

@@ -0,0 +1,58 @@
+const POST_NEW_REVIEW_PATH_PREFIX = '/posts/new?urls='
+const MAX_POST_NEW_REVIEW_TARGET_BYTES = 6_144
+
+const textEncoder = new TextEncoder ()
+
+
+const rawUrlsParam = (search: string): string | null => {
+  const query = search.startsWith ('?') ? search.slice (1) : search
+  if (query === '')
+    return null
+
+  for (const segment of query.split ('&'))
+    {
+      if (segment === 'urls')
+        return ''
+      if (segment.startsWith ('urls='))
+        return segment.slice ('urls='.length)
+    }
+
+  return null
+}
+
+
+export const buildPostNewReviewPath = (urls: string[]): string =>
+    `${ POST_NEW_REVIEW_PATH_PREFIX }${ urls.map (url => encodeURIComponent (url)).join ('+') }`
+
+
+export const postNewReviewPathByteLength = (urls: string[]): number =>
+    textEncoder.encode (buildPostNewReviewPath (urls)).byteLength
+
+
+export const isPostNewReviewPathWithinLimit = (urls: string[]): boolean =>
+    postNewReviewPathByteLength (urls) < MAX_POST_NEW_REVIEW_TARGET_BYTES
+
+
+export const parsePostNewReviewUrls = (search: string): string[] => {
+  const raw = rawUrlsParam (search)
+  if (raw == null)
+    return []
+
+  return raw
+      .split ('+')
+      .filter (segment => segment !== '')
+      .map (segment => {
+        try
+        {
+          return decodeURIComponent (segment)
+        }
+        catch
+        {
+          return segment
+        }
+      })
+}
+
+
+export const hasPostNewReviewState = (search: string): boolean =>
+    rawUrlsParam (search) != null

frontend/src/lib/useKeyboardShortcuts.tsx

@@ -25,7 +25,6 @@ import {
     getEffectiveKeyBindings,
     setClientKeyboardSettings,
 } from '@/lib/settings'
-import { useUnsavedChangesGuard } from '@/lib/useUnsavedChangesGuard'
 
 import type {
     KeyBinding,
@@ -97,7 +96,6 @@ const focusSearchTarget = (): void => {
 export const KeyboardShortcutsProvider = ({ children }: PropsWithChildren) => {
   const location = useLocation ()
   const navigate = useNavigate ()
-  const { confirmDiscardNavigation } = useUnsavedChangesGuard ()
 
   const [keyboardSettings, setKeyboardSettingsState] =
       useState<ClientKeyboardSettings> (() => getClientKeyboardSettings ())
@@ -149,11 +147,8 @@ export const KeyboardShortcutsProvider = ({ children }: PropsWithChildren) => {
   }, [])
 
   const guardedNavigate = useCallback ((path: string) => {
-    confirmDiscardNavigation ().then (confirmed => {
-      if (confirmed)
-	navigate (path)
-    })
-  }, [confirmDiscardNavigation, navigate])
+    navigate (path)
+  }, [navigate])
 
   const builtinHandlers = useMemo<ShortcutHandlers> (
       () => ({

frontend/src/lib/useUnsavedChangesGuard.test.tsx

@@ -0,0 +1,77 @@
+import { fireEvent, screen, waitFor, within } from '@testing-library/react'
+import { useState } from 'react'
+import { useLocation, useNavigate } from 'react-router-dom'
+import { describe, expect, it, vi } from 'vitest'
+
+import { useUnsavedChangesGuard } from '@/lib/useUnsavedChangesGuard'
+import { renderWithProviders } from '@/test/render'
+
+const GuardHarness = () => {
+  const [dirty, setDirty] = useState (true)
+  const location = useLocation ()
+  const navigate = useNavigate ()
+  const discard = vi.fn (() => setDirty (false))
+  const { allowNextNavigation } = useUnsavedChangesGuard ({
+    dirty,
+    onDiscard: discard })
+
+  return (
+      <>
+	<output aria-label="location">{location.pathname}{location.search}</output>
+	<button type="button" onClick={() => navigate ('/next?tab=one')}>move</button>
+	<button
+	    type="button"
+	    onClick={() => {
+	      allowNextNavigation ()
+	      navigate ('/allowed')
+	    }}>
+	  allowed move
+	</button>
+      </>)
+}
+
+describe ('useUnsavedChangesGuard', () => {
+  it ('blocks route changes and resets a cancelled transition', async () => {
+    renderWithProviders (<GuardHarness/>, { route: '/current' })
+
+    fireEvent.click (screen.getByRole ('button', { name: 'move' }))
+
+    expect (within (await screen.findByRole ('dialog')).getByText (
+	'変更が破棄してページ移動しますか?')).toBeInTheDocument ()
+    expect (screen.getByLabelText ('location')).toHaveTextContent ('/current')
+
+    fireEvent.click (screen.getByRole ('button', { name: '取消' }))
+
+    await waitFor (() => {
+      expect (screen.queryByRole ('dialog')).not.toBeInTheDocument ()
+    })
+    expect (screen.getByLabelText ('location')).toHaveTextContent ('/current')
+  })
+
+  it ('proceeds with the blocked transition after discard is confirmed', async () => {
+    renderWithProviders (<GuardHarness/>, { route: '/current' })
+
+    fireEvent.click (screen.getByRole ('button', { name: 'move' }))
+    fireEvent.click (await screen.findByRole ('button', {
+      name: '変更を破棄して移動' }))
+
+    await waitFor (() => {
+      expect (screen.getByLabelText ('location')).toHaveTextContent ('/next?tab=one')
+    })
+  })
+
+  it ('allows only the next navigation without leaving a bypass token', async () => {
+    renderWithProviders (<GuardHarness/>, { route: '/current' })
+
+    fireEvent.click (screen.getByRole ('button', { name: 'allowed move' }))
+    await waitFor (() => {
+      expect (screen.getByLabelText ('location')).toHaveTextContent ('/allowed')
+    })
+
+    fireEvent.click (screen.getByRole ('button', { name: 'move' }))
+
+    expect (within (await screen.findByRole ('dialog')).getByText (
+	'変更が破棄してページ移動しますか?')).toBeInTheDocument ()
+    expect (screen.getByLabelText ('location')).toHaveTextContent ('/allowed')
+  })
+})

frontend/src/lib/useUnsavedChangesGuard.tsx

@@ -1,6 +1,15 @@
-import { createContext, useCallback, useContext, useMemo, useState } from 'react'
+import {
+    createContext,
+    useCallback,
+    useContext,
+    useEffect,
+    useMemo,
+    useRef,
+    useState,
+} from 'react'
+import { useBlocker } from 'react-router-dom'
 
-import { useDialogue } from '@/components/dialogues/DialogueProvider'
+import { useDialogue } from '@/lib/dialogues/useDialogue'
 
 import type { FC, PropsWithChildren } from 'react'
 
@@ -8,12 +17,16 @@ type UnsavedChangesSource = {
     dirty:    boolean
     discard:  () => void | Promise<void> }
 
+type UseUnsavedChangesGuardOptions = {
+    dirty:      boolean
+    onDiscard?: () => void | Promise<void> }
+
 type UnsavedChangesGuardContextValue = {
-    hasUnsavedChanges:             boolean
-    registerUnsavedChangesSource:  (
-	source: UnsavedChangesSource | null,
-    ) => void
-    confirmDiscardNavigation:      () => Promise<boolean> }
+    hasUnsavedChanges:            boolean
+    registerUnsavedChangesSource: (
+        source: UnsavedChangesSource,
+    ) => () => void
+    allowNextNavigation:          () => void }
 
 const UnsavedChangesGuardContext =
     createContext<UnsavedChangesGuardContextValue | null> (null)
@@ -21,49 +34,171 @@ const UnsavedChangesGuardContext =
 
 export const UnsavedChangesGuardProvider: FC<PropsWithChildren> = ({ children }) => {
   const dialogue = useDialogue ()
-  const [source, setSource] = useState<UnsavedChangesSource | null> (null)
+  const sourcesRef = useRef (new Map<symbol, UnsavedChangesSource> ())
+  const bypassNextNavigationRef = useRef<symbol | null> (null)
+  const [revision, setRevision] = useState (0)
+  const dialogueOpenRef = useRef (false)
+  const handlingBlockedTransitionRef = useRef (false)
 
   const registerUnsavedChangesSource = useCallback ((
-      nextSource: UnsavedChangesSource | null,
-  ) => {
-    setSource (nextSource)
+      source: UnsavedChangesSource,
+  ): (() => void) => {
+    const sourceId = Symbol ('unsaved-changes-source')
+    sourcesRef.current.set (sourceId, source)
+    setRevision (current => current + 1)
+
+    return () => {
+      if (!(sourcesRef.current.delete (sourceId)))
+        return
+
+      setRevision (current => current + 1)
+    }
   }, [])
 
-  const confirmDiscardNavigation = useCallback (async (): Promise<boolean> => {
-    if (!(source?.dirty))
+  const allowNextNavigation = useCallback (() => {
+    const token = Symbol ('allowed-navigation')
+    bypassNextNavigationRef.current = token
+
+    queueMicrotask (() => {
+      if (bypassNextNavigationRef.current === token)
+        bypassNextNavigationRef.current = null
+    })
+  }, [])
+
+  const sources = useMemo (
+      () => [...sourcesRef.current.values ()],
+      [revision],
+  )
+  const dirtySources = useMemo (
+      () => sources.filter (source => source.dirty),
+      [sources],
+  )
+  const hasUnsavedChanges = dirtySources.length > 0
+  const hasUnsavedChangesRef = useRef (hasUnsavedChanges)
+  hasUnsavedChangesRef.current = hasUnsavedChanges
+  const shouldBlock = useCallback (() => {
+    if (bypassNextNavigationRef.current != null)
+      {
+        bypassNextNavigationRef.current = null
+        return false
+      }
+
+    return hasUnsavedChangesRef.current
+  }, [])
+  const blocker = useBlocker (shouldBlock)
+
+  const confirmDiscardChanges = useCallback (async (): Promise<boolean> => {
+    if (!(hasUnsavedChanges))
       return true
 
-    const confirmed = await dialogue.confirm ({
-	title: '未保存の変更があります',
-	description: 'このまま移動すると、保存していない変更は失われます。',
-	cancelText: 'このページに残る',
-	confirmText: '変更を破棄して移動',
-	variant: 'danger' })
-    if (!(confirmed))
+    if (dialogueOpenRef.current)
       return false
 
-    await source.discard ()
-    return true
-  }, [dialogue, source])
+    dialogueOpenRef.current = true
+
+    try
+    {
+      const confirmed = await dialogue.confirm ({
+          title: '変更が破棄してページ移動しますか?',
+          confirmText: '変更を破棄して移動',
+          variant: 'danger' })
+      if (!(confirmed))
+        return false
+
+      return true
+    }
+    finally
+    {
+      dialogueOpenRef.current = false
+    }
+  }, [dialogue, hasUnsavedChanges])
+
+  useEffect (() => {
+    if (blocker.state !== 'blocked' || handlingBlockedTransitionRef.current)
+      return
+
+    handlingBlockedTransitionRef.current = true
+    void (async () => {
+      try
+      {
+        const confirmed = await confirmDiscardChanges ()
+        if (!(confirmed))
+          {
+            blocker.reset ()
+            return
+          }
+
+        let discardResults: Array<void | Promise<void>>
+        try
+        {
+	  discardResults = dirtySources.map (source => source.discard ())
+        }
+        catch
+        {
+	  blocker.reset ()
+	  return
+        }
+
+        blocker.proceed ()
+        await Promise.allSettled (discardResults)
+      }
+      finally
+      {
+        handlingBlockedTransitionRef.current = false
+      }
+    }) ()
+  }, [blocker, confirmDiscardChanges, dirtySources])
+
+  useEffect (() => {
+    if (!(hasUnsavedChanges))
+      return
+
+    const handleBeforeUnload = (event: BeforeUnloadEvent) => {
+      event.preventDefault ()
+      event.returnValue = ''
+    }
+
+    window.addEventListener ('beforeunload', handleBeforeUnload)
+    return () => {
+      window.removeEventListener ('beforeunload', handleBeforeUnload)
+    }
+  }, [hasUnsavedChanges])
 
   const value = useMemo<UnsavedChangesGuardContextValue> (() => ({
-      hasUnsavedChanges: source?.dirty === true,
+      hasUnsavedChanges,
       registerUnsavedChangesSource,
-      confirmDiscardNavigation,
-  }), [confirmDiscardNavigation, registerUnsavedChangesSource, source?.dirty])
+      allowNextNavigation,
+  }), [
+      allowNextNavigation,
+      hasUnsavedChanges,
+      registerUnsavedChangesSource,
+  ])
 
   return (
       <UnsavedChangesGuardContext.Provider value={value}>
-	{children}
+        {children}
       </UnsavedChangesGuardContext.Provider>)
 }
 
 
-export const useUnsavedChangesGuard = (): UnsavedChangesGuardContextValue => {
+export const useUnsavedChangesGuard = (
+    options?: UseUnsavedChangesGuardOptions,
+): UnsavedChangesGuardContextValue => {
   const context = useContext (UnsavedChangesGuardContext)
 
   if (context == null)
     throw new Error ('UnsavedChangesGuardProvider が必要です．')
 
+  const { registerUnsavedChangesSource } = context
+
+  useEffect (() => {
+    if (options == null)
+      return
+
+    return registerUnsavedChangesSource ({
+        dirty: options.dirty,
+        discard: options.onDiscard ?? (() => undefined) })
+  }, [options?.dirty, options?.onDiscard, registerUnsavedChangesSource])
+
   return context
 }

frontend/src/pages/materials/MaterialListPage.tsx

@@ -13,7 +13,7 @@ import MainArea from '@/components/layout/MainArea'
 import { SITE_TITLE } from '@/config'
 import { fetchMaterials, parseMaterialFilter } from '@/lib/materials'
 import { materialsKeys } from '@/lib/queryKeys'
-import { dateString, inputClass } from '@/lib/utils'
+import { cn, dateString, inputClass } from '@/lib/utils'
 
 import type { FC, FormEvent } from 'react'
 
@@ -113,10 +113,11 @@ const clearedTagSelectionPath = (
 
 const MaterialThumb: FC<{ material: Material }> = ({ material }) => (
     <div
-	className={`flex aspect-square h-[180px] w-[180px] items-center justify-center
-		    overflow-hidden rounded-lg border border-stone-200 bg-white text-center
-		    text-stone-900 shadow-sm dark:border-stone-700 dark:bg-stone-900
-		    dark:text-stone-100`}>
+	className={cn (
+	    'flex aspect-square h-[180px] w-[180px] items-center justify-center',
+	    'overflow-hidden rounded-lg border border-stone-200 bg-white text-center',
+	    'text-stone-900 shadow-sm dark:border-stone-700 dark:bg-stone-900',
+	    'dark:text-stone-100')}>
       {material.thumbnail
        ? <img src={material.thumbnail} alt="" className="block h-full w-full object-cover"/>
        : (
@@ -482,7 +483,7 @@ const MaterialListPage: FC = () => {
 			className={inputClass (invalid)}>
 		      <option value="all">すべて</option>
 		      <option value="tagged">タグあり</option>
-		      <option value="untagged">タグなし</option>
+		      <option value="untagged"></option>
 		    </select>)}
 	      </FormField>
 
@@ -531,30 +532,32 @@ const MaterialListPage: FC = () => {
 
 	  <div className="flex flex-wrap items-center justify-between gap-3">
 	    <div className="flex flex-wrap gap-2">
-	      <button
-		  type="button"
-		  onClick={() => updateQuery ({ view: 'card' })}
-		  className={`rounded-full border px-4 py-2 text-sm ${
-		      view === 'card'
-		      ? [
-			  'border-sky-500 bg-sky-50 text-sky-700 dark:border-sky-400',
-			  'dark:bg-sky-950 dark:text-sky-100'].join (' ')
-		      : [
-			  'border-stone-300 bg-white text-stone-900 dark:border-stone-700',
-			  'dark:bg-stone-900 dark:text-stone-100'].join (' ') }`}>
+		      <button
+			  type="button"
+			  onClick={() => updateQuery ({ view: 'card' })}
+			  className={cn (
+			      'rounded-full border px-4 py-2 text-sm',
+			      view === 'card'
+			      ? [
+				  'border-sky-500 bg-sky-50 text-sky-700 dark:border-sky-400',
+				  'dark:bg-sky-950 dark:text-sky-100']
+			      : [
+				  'border-stone-300 bg-white text-stone-900 dark:border-stone-700',
+				  'dark:bg-stone-900 dark:text-stone-100'])}>
 		アイコン
 	      </button>
-	      <button
-		  type="button"
-		  onClick={() => updateQuery ({ view: 'list' })}
-		  className={`rounded-full border px-4 py-2 text-sm ${
-		      view === 'list'
-		      ? [
-			  'border-sky-500 bg-sky-50 text-sky-700 dark:border-sky-400',
-			  'dark:bg-sky-950 dark:text-sky-100'].join (' ')
-		      : [
-			  'border-stone-300 bg-white text-stone-900 dark:border-stone-700',
-			  'dark:bg-stone-900 dark:text-stone-100'].join (' ') }`}>
+		      <button
+			  type="button"
+			  onClick={() => updateQuery ({ view: 'list' })}
+			  className={cn (
+			      'rounded-full border px-4 py-2 text-sm',
+			      view === 'list'
+			      ? [
+				  'border-sky-500 bg-sky-50 text-sky-700 dark:border-sky-400',
+				  'dark:bg-sky-950 dark:text-sky-100']
+			      : [
+				  'border-stone-300 bg-white text-stone-900 dark:border-stone-700',
+				  'dark:bg-stone-900 dark:text-stone-100'])}>
 		詳細
 	      </button>
 	    </div>

frontend/src/pages/posts/PostImportResultPage.test.tsx

@@ -1,402 +0,0 @@
-import { act, fireEvent, render, screen, waitFor } from '@testing-library/react'
-import { HelmetProvider } from 'react-helmet-async'
-import { MemoryRouter, Route, Routes } from 'react-router-dom'
-import { beforeEach, describe, expect, it, vi } from 'vitest'
-
-import {
-  loadPostImportSession,
-  savePostImportSession,
-} from '@/lib/postImportSession'
-import PostImportResultPage from '@/pages/posts/PostImportResultPage'
-import { buildUser } from '@/test/factories'
-import { buildPostImportRow } from '@/test/postImportFactories'
-import { originalCreatedAtString } from '@/lib/utils'
-
-import type { PostImportRow } from '@/lib/postImportSession'
-import type { DialogueFormAction, DialogueFormControls } from '@/lib/dialogues/useDialogue'
-
-const api = vi.hoisted (() => ({
-  apiGet: vi.fn (),
-  apiPost: vi.fn (),
-}))
-
-const toastApi = vi.hoisted (() => ({
-  toast: vi.fn (),
-}))
-
-const dialogue = vi.hoisted (() => ({
-  form: vi.fn (() => Promise.resolve ()),
-}))
-
-vi.mock ('@/components/ui/use-toast', () => toastApi)
-vi.mock ('@/lib/api', () => api)
-vi.mock ('@/lib/dialogues/useDialogue', () => ({
-  default: () => dialogue,
-}))
-
-describe ('PostImportResultPage', () => {
-  beforeEach (() => {
-    sessionStorage.clear ()
-    vi.clearAllMocks ()
-    globalThis.URL.createObjectURL = vi.fn (() => 'blob:preview')
-    globalThis.URL.revokeObjectURL = vi.fn ()
-    api.apiGet.mockResolvedValue (new Blob (['img'], { type: 'image/png' }))
-  })
-
-  it ('shows edit and retry only for recoverable failures and shows warnings', () => {
-    savePostImportSession ('result-session', {
-      source: '',
-      repairMode: 'failed',
-      rows: [
-        buildPostImportRow ({
-          sourceRow: 1,
-          attributes: { title: 'recoverable row' },
-          importStatus: 'failed',
-          recoverable: true,
-          importErrors: { base: ['recoverable failed'] } }),
-        buildPostImportRow ({
-          sourceRow: 2,
-          attributes: { title: 'hard failed row' },
-          importStatus: 'failed',
-          importErrors: { base: ['hard failed'] } }),
-        buildPostImportRow ({
-          sourceRow: 3,
-          attributes: {
-            title: 'created row',
-            originalCreatedFrom: '2024-01-01T00:00:00Z',
-            originalCreatedBefore: '2024-01-02T00:00:00Z' },
-          importStatus: 'created',
-          createdPostId: 3,
-          fieldWarnings: {
-            thumbnailBase: ['サムネール画像を取得できませんでした．'] } })] })
-
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/result-session/result']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<PostImportResultPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    expect (screen.getAllByRole ('button', { name: '編輯' })).toHaveLength (1)
-    expect (screen.getAllByRole ('button', { name: '再試行' })).toHaveLength (1)
-    expect (screen.getByText ('サムネール画像を取得できませんでした．'))
-        .toBeInTheDocument ()
-    expect (screen.getByText (
-        originalCreatedAtString ('2024-01-01T00:00:00Z', '2024-01-02T00:00:00Z'),
-    )).toBeInTheDocument ()
-  })
-
-  it ('shows hour-precision original-created ranges with the shared utility output', () => {
-    const from = '2024-01-01T12:00:00Z'
-    const before = '2024-01-01T13:00:00Z'
-    savePostImportSession ('result-hour-range', {
-      source: '',
-      repairMode: 'all',
-      rows: [buildPostImportRow ({
-        sourceRow: 1,
-        importStatus: 'created',
-        createdPostId: 1,
-        attributes: {
-          title: 'created row',
-          originalCreatedFrom: from,
-          originalCreatedBefore: before } })] })
-
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/result-hour-range/result']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<PostImportResultPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    expect (screen.getByText (originalCreatedAtString (from, before))).toBeInTheDocument ()
-  })
-
-  it ('keeps recoverable pending rows actionable and hides actions for hard failures', () => {
-    savePostImportSession ('result-pending', {
-      source: '',
-      repairMode: 'failed',
-      rows: [
-        buildPostImportRow ({
-          sourceRow: 1,
-          importStatus: 'pending',
-          recoverable: true,
-          validationErrors: { title: ['invalid'] } }),
-        buildPostImportRow ({
-          sourceRow: 2,
-          importStatus: 'pending',
-          recoverable: true }),
-        buildPostImportRow ({
-          sourceRow: 3,
-          importStatus: 'failed',
-          importErrors: { base: ['hard failed'] } })] })
-
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/result-pending/result']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<PostImportResultPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    expect (screen.getAllByRole ('button', { name: '編輯' })).toHaveLength (1)
-    expect (screen.getAllByRole ('button', { name: '再試行' })).toHaveLength (1)
-    expect (screen.getByText ('invalid')).toBeInTheDocument ()
-    expect (screen.getByText ('hard failed')).toBeInTheDocument ()
-  })
-
-  it ('disables editing, retry, and navigation while retry is running', async () => {
-    let resolveValidation: ((value: { rows: PostImportRow[] }) => void) | null = null
-    savePostImportSession ('result-retry-busy', {
-      source: '',
-      repairMode: 'failed',
-      rows: [
-        buildPostImportRow ({
-          sourceRow: 1,
-          importStatus: 'failed',
-          recoverable: true,
-          importErrors: { base: ['failed'] } }),
-        buildPostImportRow ({
-          sourceRow: 2,
-          importStatus: 'failed',
-          recoverable: true,
-          importErrors: { base: ['failed'] } })] })
-    api.apiPost.mockImplementationOnce (() =>
-        new Promise<{ rows: PostImportRow[] }> (resolve => {
-          resolveValidation = resolve
-        }))
-    api.apiPost.mockResolvedValueOnce ({
-      created: 0,
-      skipped: 0,
-      failed: 0,
-      rows: [] })
-
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/result-retry-busy/result']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<PostImportResultPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    fireEvent.click (screen.getAllByRole ('button', { name: '再試行' })[0])
-
-    await waitFor (() => {
-      screen.getAllByRole ('button', { name: '編輯' }).forEach (button => {
-        expect (button).toBeDisabled ()
-      })
-      screen.getAllByRole ('button', { name: '再試行' }).forEach (button => {
-        expect (button).toBeDisabled ()
-      })
-      expect (screen.getByRole ('button', { name: '確認画面へ戻る' })).toBeDisabled ()
-      expect (screen.getByRole ('button', { name: '新しい URL リストを入力' })).toBeDisabled ()
-    })
-
-    resolveValidation?.({ rows: [buildPostImportRow ({ sourceRow: 1 })] })
-  })
-
-  it ('persists retry success to sessionStorage', async () => {
-    savePostImportSession ('result-retry-success', {
-      source: '',
-      repairMode: 'failed',
-      rows: [buildPostImportRow ({
-        sourceRow: 1,
-        importStatus: 'failed',
-        recoverable: true,
-        importErrors: { base: ['failed'] } })] })
-    api.apiPost
-        .mockResolvedValueOnce ({
-          rows: [buildPostImportRow ({
-            sourceRow: 1,
-            importStatus: 'pending',
-            recoverable: true })] })
-        .mockResolvedValueOnce ({
-          created: 1,
-          skipped: 0,
-          failed: 0,
-          rows: [{
-            sourceRow: 1,
-            status: 'created',
-            post: { id: 10 } }] })
-
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/result-retry-success/result']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<PostImportResultPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    fireEvent.click (screen.getByRole ('button', { name: '再試行' }))
-
-    await waitFor (() => {
-      expect (loadPostImportSession ('result-retry-success')?.rows[0]?.importStatus)
-          .toBe ('created')
-    })
-  })
-
-  it ('keeps edited recoverable rows in session and retries with the edited values', async () => {
-    savePostImportSession ('result-edit-retry', {
-      source: '',
-      repairMode: 'failed',
-      rows: [buildPostImportRow ({
-        sourceRow: 1,
-        attributes: { title: 'old title' },
-        importStatus: 'failed',
-        recoverable: true,
-        importErrors: { base: ['failed'] } })] })
-    api.apiPost
-        .mockResolvedValueOnce ({
-          rows: [buildPostImportRow ({
-            sourceRow: 1,
-            attributes: { title: 'edited title' },
-            importStatus: 'pending',
-            recoverable: true })] })
-        .mockResolvedValueOnce ({
-          rows: [buildPostImportRow ({
-            sourceRow: 1,
-            attributes: { title: 'edited title' },
-            importStatus: 'pending',
-            recoverable: true })] })
-        .mockResolvedValueOnce ({
-          created: 1,
-          skipped: 0,
-          failed: 0,
-          rows: [{
-            sourceRow: 1,
-            status: 'created',
-            post: { id: 11 } }] })
-    dialogue.form.mockImplementationOnce (async options => {
-      let actions: DialogueFormAction[] = []
-      const controls: DialogueFormControls = {
-        close: vi.fn (),
-        confirm: vi.fn (),
-        setActions: next => {
-          actions = next
-        } }
-
-      render (options.body (controls))
-      await waitFor (() => expect (actions.length).toBe (2))
-      fireEvent.change (screen.getByDisplayValue ('old title'), {
-        target: { value: 'edited title' } })
-      await act (async () => {
-        await actions.find (action => action.label === '編輯内容を保存')?.onSelect ()
-      })
-    })
-
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/result-edit-retry/result']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<PostImportResultPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    fireEvent.click (screen.getByRole ('button', { name: '編輯' }))
-
-    await waitFor (() => {
-      const saved = loadPostImportSession ('result-edit-retry')
-      expect (saved?.rows[0]?.attributes.title).toBe ('edited title')
-      expect (saved?.rows[0]?.importStatus).toBe ('pending')
-    })
-
-    fireEvent.click (screen.getByRole ('button', { name: '再試行' }))
-
-    await waitFor (() => {
-      expect (api.apiPost.mock.calls[2]?.[1]?.rows?.[0]?.attributes?.title)
-          .toBe ('edited title')
-    })
-  })
-
-  it ('persists restored failed state when retry fails', async () => {
-    savePostImportSession ('result-retry-failure', {
-      source: '',
-      repairMode: 'failed',
-      rows: [buildPostImportRow ({
-        sourceRow: 1,
-        importStatus: 'failed',
-        recoverable: true,
-        importErrors: { base: ['failed'] } })] })
-    api.apiPost.mockRejectedValueOnce (new Error ('network error'))
-
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/result-retry-failure/result']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<PostImportResultPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    fireEvent.click (screen.getByRole ('button', { name: '再試行' }))
-
-    await waitFor (() => {
-      const saved = loadPostImportSession ('result-retry-failure')
-      expect (saved?.rows[0]?.importStatus).toBe ('failed')
-      expect (saved?.rows[0]?.recoverable).toBe (true)
-    })
-  })
-
-  it ('restores the failed row when the retry import response is incomplete', async () => {
-    savePostImportSession ('result-retry-missing-row', {
-      source: '',
-      repairMode: 'failed',
-      rows: [buildPostImportRow ({
-        sourceRow: 1,
-        importStatus: 'failed',
-        recoverable: true,
-        importErrors: { base: ['failed'] } })] })
-    api.apiPost
-        .mockResolvedValueOnce ({
-          rows: [buildPostImportRow ({
-            sourceRow: 1,
-            importStatus: 'pending',
-            recoverable: true })] })
-        .mockResolvedValueOnce ({
-          created: 1,
-          skipped: 0,
-          failed: 0,
-          rows: [] })
-
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/result-retry-missing-row/result']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<PostImportResultPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    fireEvent.click (screen.getByRole ('button', { name: '再試行' }))
-
-    await waitFor (() => {
-      const saved = loadPostImportSession ('result-retry-missing-row')
-      expect (saved?.rows[0]?.importStatus).toBe ('failed')
-      expect (toastApi.toast).toHaveBeenCalledWith (
-          expect.objectContaining ({ title: '登録結果が不完全でした' }))
-    })
-  })
-})

frontend/src/pages/posts/PostImportResultPage.tsx

@@ -1,544 +0,0 @@
-import { useEffect, useMemo, useRef, useState } from 'react'
-import { Helmet } from 'react-helmet-async'
-import { useNavigate, useParams } from 'react-router-dom'
-
-import FieldError from '@/components/common/FieldError'
-import FieldWarning from '@/components/common/FieldWarning'
-import PageTitle from '@/components/common/PageTitle'
-import PrefetchLink from '@/components/PrefetchLink'
-import MainArea from '@/components/layout/MainArea'
-import PostImportRowForm from '@/components/posts/import/PostImportRowForm'
-import PostImportStatusBadge from '@/components/posts/import/PostImportStatusBadge'
-import { displayPostImportStatus } from '@/components/posts/import/postImportRowStatus'
-import { Button } from '@/components/ui/button'
-import { toast } from '@/components/ui/use-toast'
-import { SITE_TITLE } from '@/config'
-import { apiPost } from '@/lib/api'
-import useDialogue from '@/lib/dialogues/useDialogue'
-import { canEditContent } from '@/lib/users'
-import { clearPostImportSourceDraft,
-	 buildNextEditedRow,
-	 canEditResultRow,
-	 canRetryResultRow,
-	 hasExactSourceRows,
-	 initialisePreviewRows,
-	 loadPostImportSession,
-	 mergeImportResults,
-	 mergeValidatedImportRow,
-	 replaceImportRow,
-	 resultRepairMode,
-	 resultRowMessages,
-	 resultRowWarnings,
-	 resultSummaryCounts,
-	 retryImportRow,
-	 savePostImportSession } from '@/lib/postImportSession'
-import { originalCreatedAtString } from '@/lib/utils'
-import Forbidden from '@/pages/Forbidden'
-
-import type { FC } from 'react'
-
-import type { PostImportRowDraft } from '@/components/posts/import/PostImportRowForm'
-import type { PostImportResultRow, PostImportRow } from '@/lib/postImportSession'
-import type { PostImportSession } from '@/lib/postImportSession'
-import type { User } from '@/types'
-
-type Props = { user: User | null }
-
-
-const PostImportResultPage: FC<Props> = ({ user }) => {
-  const editable = canEditContent (user)
-  const dialogue = useDialogue ()
-  const navigate = useNavigate ()
-  const { sessionId } = useParams ()
-
-  const [session, setSession] = useState<PostImportSession | null> (null)
-  const [missing, setMissing] = useState (false)
-  const [loadingRow, setLoadingRow] = useState<number | null> (null)
-  const [, setEditingRow] = useState<PostImportRow | null> (null)
-  const sessionRef = useRef<PostImportSession | null> (null)
-
-  useEffect (() => {
-    if (sessionId == null)
-      return
-
-    const loaded = loadPostImportSession (sessionId, message =>
-	toast ({ title: '取込状態を復元できませんでした', description: message }))
-    setSession (loaded)
-    setMissing (loaded == null)
-  }, [sessionId])
-
-  useEffect (() => {
-    if (sessionId == null || session == null)
-      return
-
-    savePostImportSession (sessionId, session, message =>
-	toast ({ title: '取込状態を保存できませんでした', description: message }))
-  }, [session, sessionId])
-
-  useEffect (() => {
-    sessionRef.current = session
-  }, [session])
-
-  const counts = useMemo (
-      () => resultSummaryCounts (session?.rows ?? []),
-      [session])
-  const busy = loadingRow != null
-
-  const persistSession = (nextSession: PostImportSession) => {
-    if (sessionId == null)
-      return
-
-    savePostImportSession (sessionId, nextSession, message =>
-        toast ({ title: '取込状態を保存できませんでした', description: message }))
-  }
-
-  const saveDraft = async (
-      row: PostImportRow,
-      { draft, resetRequested }: {
-	  draft:            PostImportRowDraft
-	  resetRequested:   boolean },
-  ): Promise<{ saved: boolean
-	       row:   PostImportRow | null }> => {
-    const currentSession = sessionRef.current
-    if (currentSession == null)
-      return { saved: false, row: null }
-    if (!(canEditResultRow (row)))
-      return { saved: false, row: null }
-
-    const baseRow =
-	resetRequested
-	? { ...row,
-	    url: row.resetSnapshot.url,
-	    attributes: { ...row.resetSnapshot.attributes },
-	    provenance: { ...row.resetSnapshot.provenance },
-	    tagSources: { ...row.resetSnapshot.tagSources },
-	    fieldWarnings: Object.fromEntries (
-		Object.entries (row.resetSnapshot.fieldWarnings)
-		    .map (([key, values]) => [key, [...values]])),
-	    baseWarnings: [...row.resetSnapshot.baseWarnings],
-	    metadataUrl: row.resetSnapshot.metadataUrl }
-	: row
-    const urlChanged = draft.url !== baseRow.url
-    const nextRow = buildNextEditedRow (baseRow, draft, urlChanged)
-
-    const nextRows = currentSession.rows.map (row =>
-		row.sourceRow === baseRow.sourceRow
-		? nextRow
-		: row)
-    try
-    {
-      const validated = await apiPost<{ rows: PostImportRow[] }> ('/posts/import/validate', {
-	  rows:
-	      nextRows
-	      .filter (row => row.importStatus !== 'created')
-	      .map (row => ({ sourceRow: row.sourceRow,
-			      url: row.url,
-			      attributes: row.attributes,
-			      provenance: row.provenance,
-			      tagSources: row.tagSources,
-			      metadataUrl: row.metadataUrl })),
-	  changed_row: urlChanged ? baseRow.sourceRow : -1 })
-      const validatedRows = initialisePreviewRows (validated.rows)
-      const target = validatedRows.find (
-          validatedRow => validatedRow.sourceRow === baseRow.sourceRow)
-      const latestSession = sessionRef.current
-      if (latestSession == null)
-        return { saved: false, row: null }
-      if (target == null)
-        {
-          const restoredRows = replaceImportRow (latestSession.rows, row)
-          const restoredSession = {
-              ...latestSession,
-              rows: restoredRows,
-              repairMode: resultRepairMode (restoredRows) }
-          sessionRef.current = restoredSession
-          setSession (restoredSession)
-          toast ({ title: '行の再検証結果が不完全でした' })
-          return { saved: false, row: null }
-        }
-      const editedRows = replaceImportRow (latestSession.rows, nextRow)
-      const rows = mergeValidatedImportRow (editedRows, target)
-      const nextSession = {
-          ...latestSession,
-          rows,
-          repairMode: resultRepairMode (rows) }
-      sessionRef.current = nextSession
-      setSession (nextSession)
-      persistSession (nextSession)
-      const mergedTarget =
-          rows.find (mergedRow => mergedRow.sourceRow === baseRow.sourceRow)
-          ?? target
-      if (Object.keys (mergedTarget.validationErrors).length > 0)
-        return { saved: false, row: mergedTarget }
-      return { saved: true, row: null }
-    }
-    catch
-    {
-      toast ({ title: '行の再検証に失敗しました' })
-      return { saved: false, row: null }
-    }
-  }
-
-  const openEditingDialogue = async (row: PostImportRow) => {
-    const saveRowDraft = (
-	{ draft, resetRequested }: {
-	    draft:          PostImportRowDraft
-	    resetRequested: boolean },
-    ) =>
-	saveDraft (row, { draft, resetRequested })
-
-    await dialogue.form ({
-	title: '投稿を編輯',
-	description: `投稿 ${ row.sourceRow } の内容を確認し、必要な項目を編輯してください．`,
-	cancelText: '取消',
-	size: 'large',
-	body: controls => (
-	    <PostImportRowForm
-		row={row}
-		controls={controls}
-		onSave={saveRowDraft}/>) })
-  }
-
-  const editRow = async (row: PostImportRow) => {
-    setEditingRow (row)
-    try
-    {
-      await openEditingDialogue (row)
-    }
-    finally
-    {
-      setEditingRow (current =>
-          current?.sourceRow === row.sourceRow
-          ? null
-          : current)
-    }
-  }
-
-  const retry = async (sourceRow: number) => {
-    if (session == null || sessionId == null || loadingRow != null)
-      return
-
-    const initialSession = sessionRef.current
-    if (initialSession == null)
-      return
-
-    setLoadingRow (sourceRow)
-    const originalRow = initialSession.rows.find (row => row.sourceRow === sourceRow)
-    if (originalRow == null)
-      {
-        setLoadingRow (null)
-        return
-      }
-    try
-    {
-      const pendingRows = retryImportRow (initialSession.rows, sourceRow)
-      const pendingSession = { ...initialSession, rows: pendingRows }
-      sessionRef.current = pendingSession
-      setSession (pendingSession)
-      persistSession (pendingSession)
-      const requestedRows = pendingRows.filter (row => row.importStatus !== 'created')
-      const validated = await apiPost<{ rows: PostImportRow[] }> ('/posts/import/validate', {
-          rows: requestedRows.map (row => ({
-                  sourceRow: row.sourceRow,
-                  url: row.url,
-                  attributes: row.attributes,
-                  provenance: row.provenance,
-                  tagSources: row.tagSources,
-                  metadataUrl: row.metadataUrl })),
-          changed_row: -1 })
-      const validatedRows = initialisePreviewRows (validated.rows)
-      if (!(hasExactSourceRows (requestedRows.map (row => row.sourceRow), validatedRows)))
-        {
-          const latest = sessionRef.current ?? pendingSession
-          const restoredRows = replaceImportRow (latest.rows, originalRow)
-          const restoredSession = {
-              ...latest,
-              rows: restoredRows,
-              repairMode: resultRepairMode (restoredRows) }
-          sessionRef.current = restoredSession
-          setSession (restoredSession)
-          persistSession (restoredSession)
-          toast ({ title: '再検証結果が不完全でした' })
-          return
-        }
-      const validatedTarget = validatedRows.find (
-          row => row.sourceRow === sourceRow)
-      if (validatedTarget == null)
-        {
-          const latest = sessionRef.current ?? pendingSession
-          const restoredRows = replaceImportRow (latest.rows, originalRow)
-          const restoredSession = {
-              ...latest,
-              rows: restoredRows,
-              repairMode: resultRepairMode (restoredRows) }
-          sessionRef.current = restoredSession
-          setSession (restoredSession)
-          persistSession (restoredSession)
-          toast ({ title: '再検証結果が不完全でした' })
-          return
-        }
-      const latestAfterValidate = sessionRef.current ?? pendingSession
-      const mergedValidatedRows = mergeValidatedImportRow (
-          latestAfterValidate.rows,
-          validatedTarget)
-      const nextSession = {
-          ...latestAfterValidate,
-          rows: mergedValidatedRows,
-          repairMode: resultRepairMode (mergedValidatedRows) }
-      sessionRef.current = nextSession
-      setSession (nextSession)
-      persistSession (nextSession)
-      const target = mergedValidatedRows.find (row => row.sourceRow === sourceRow)
-      if (target == null)
-        {
-          const restoredRows = replaceImportRow (latestAfterValidate.rows, originalRow)
-          const restoredSession = {
-              ...latestAfterValidate,
-              rows: restoredRows,
-              repairMode: resultRepairMode (restoredRows) }
-          sessionRef.current = restoredSession
-          setSession (restoredSession)
-          persistSession (restoredSession)
-          toast ({ title: '再検証結果が不完全でした' })
-          return
-        }
-      if (Object.keys (target.validationErrors ?? { }).length > 0)
-        {
-          const saved = savePostImportSession (sessionId, nextSession, message =>
-              toast ({ title: '取込状態を保存できませんでした', description: message }))
-          if (saved)
-            void editRow (target)
-          return
-        }
-
-      const result = await apiPost<{
-          created: number
-          skipped: number
-          failed:  number
-          rows:    PostImportResultRow[] }> ('/posts/import', {
-              rows: [{
-                  sourceRow: target.sourceRow,
-                  url: target.url,
-                  attributes: target.attributes,
-                  provenance: target.provenance,
-                  tagSources: target.tagSources,
-                  metadataUrl: target.metadataUrl }] })
-      if (!(hasExactSourceRows ([sourceRow], result.rows)))
-        {
-          const latest = sessionRef.current ?? nextSession
-          const restoredRows = replaceImportRow (latest.rows, originalRow)
-          const restoredSession = {
-              ...latest,
-              rows: restoredRows,
-              repairMode: resultRepairMode (restoredRows) }
-          sessionRef.current = restoredSession
-          setSession (restoredSession)
-          persistSession (restoredSession)
-          toast ({ title: '登録結果が不完全でした' })
-          return
-        }
-      const latestAfterImport = sessionRef.current ?? nextSession
-      const mergedRows = mergeImportResults (latestAfterImport.rows, result.rows)
-      const recoverableRows = result.rows.filter (row =>
-          row.status === 'failed'
-          && row.recoverable
-          && Object.keys (row.errors ?? { }).length > 0)
-      const nextRows = mergedRows.map ((row): PostImportRow => {
-        const recoverable = recoverableRows.find (
-            recoverableRow => recoverableRow.sourceRow === row.sourceRow)
-        if (recoverable == null)
-          return row
-        return {
-            ...row,
-            importStatus: 'pending',
-            recoverable: true,
-            validationErrors: recoverable.errors ?? { },
-            importErrors: undefined }
-      })
-      const recoverableTarget = nextRows.find (row => row.sourceRow === sourceRow)
-      const resultSession = {
-          ...nextSession,
-          rows: nextRows,
-          repairMode: resultRepairMode (nextRows) }
-      sessionRef.current = resultSession
-      setSession (resultSession)
-      persistSession (resultSession)
-      if (recoverableTarget != null
-          && Object.keys (recoverableTarget.validationErrors).length > 0)
-        {
-          const saved = savePostImportSession (sessionId, resultSession, message =>
-              toast ({ title: '取込状態を保存できませんでした', description: message }))
-          if (saved)
-            void editRow (recoverableTarget)
-          return
-        }
-    }
-    catch
-    {
-      const latest = sessionRef.current
-      if (latest != null)
-        {
-          const restoredRows = replaceImportRow (latest.rows, originalRow)
-          const restoredSession = {
-              ...latest,
-              rows: restoredRows,
-              repairMode: resultRepairMode (restoredRows) }
-          sessionRef.current = restoredSession
-          setSession (restoredSession)
-          persistSession (restoredSession)
-        }
-      toast ({ title: '再試行に失敗しました' })
-    }
-    finally
-    {
-      setLoadingRow (null)
-    }
-  }
-
-  const openRepair = (sourceRow: number) => {
-    const currentSession = sessionRef.current
-    if (currentSession == null || sessionId == null || loadingRow != null)
-      return
-
-    const nextSession = { ...currentSession, repairMode: 'failed' as const }
-    sessionRef.current = nextSession
-    setSession (nextSession)
-    const saved = savePostImportSession (sessionId, nextSession, message =>
-	toast ({ title: '取込状態を保存できませんでした', description: message }))
-    if (!(saved))
-      return
-    const row = nextSession.rows.find (rowValue => rowValue.sourceRow === sourceRow)
-    if (row != null)
-      void editRow (row)
-  }
-
-  if (!(editable))
-    return <Forbidden/>
-
-  if (missing || sessionId == null || session == null)
-    {
-      return (
-	  <MainArea>
-	    <div className="mx-auto max-w-4xl space-y-4 p-4">
-	      <PageTitle>投稿インポート結果</PageTitle>
-	      <FieldError messages={['取込状態が見つかりません．']}/>
-	      <Button type="button" onClick={() => navigate ('/posts/import')}>
-		URL リスト入力へ戻る
-	      </Button>
-	    </div>
-	  </MainArea>)
-    }
-
-  return (
-      <MainArea>
-	<Helmet>
-	  <title>{`投稿インポート結果 | ${ SITE_TITLE }`}</title>
-	</Helmet>
-
-	<div className="mx-auto max-w-5xl space-y-4 p-4">
-	  <PageTitle>登録結果</PageTitle>
-
-	  <div className="text-sm text-neutral-700 dark:text-neutral-200">
-	    登録成功 {counts.created}件　スキップ {counts.skipped}件　失敗 {counts.failed}件
-	  </div>
-
-	  <div className="space-y-3">
-	    {session.rows.map (row => {
-	      const displayStatus = displayPostImportStatus (row)
-	      const canEdit = canEditResultRow (row)
-	      const canRetry = canRetryResultRow (row)
-	      return (
-		  <div
-		      key={row.sourceRow}
-		      className="rounded-lg border p-4 transition-shadow hover:shadow-sm">
-		    <div className="flex flex-col gap-3 md:flex-row md:items-start
-				    md:justify-between">
-		      <div className="space-y-2">
-			<div className="flex flex-wrap items-center gap-2">
-			  <span className="text-sm font-medium">行 {row.sourceRow}</span>
-			  {displayStatus != null && <PostImportStatusBadge value={displayStatus}/>}
-			</div>
-			<div className="text-sm text-neutral-700 dark:text-neutral-200">
-			  {String (row.attributes.title ?? '') || row.url}
-			</div>
-			<div className="text-xs text-neutral-500 dark:text-neutral-400">
-			  {row.url}
-			</div>
-			<div className="text-xs text-neutral-500 dark:text-neutral-400">
-			  {String (row.attributes.tags ?? '') || 'タグなし'}
-			</div>
-			<div className="text-xs text-neutral-500 dark:text-neutral-400">
-			  {originalCreatedAtString (
-			      row.attributes.originalCreatedFrom?.toString () ?? null,
-			      row.attributes.originalCreatedBefore?.toString () ?? null)}
-			  {row.attributes.duration ? ` / ${ row.attributes.duration }` : ''}
-			</div>
-			<FieldWarning messages={resultRowWarnings (row)}/>
-			<FieldError messages={resultRowMessages (row)}/>
-		      </div>
-
-		      <div className="flex flex-col gap-2 sm:flex-row">
-			{(row.createdPostId != null || row.existingPostId != null) && (
-			    <Button type="button" variant="outline" asChild>
-			      <PrefetchLink
-				  to={`/posts/${ row.createdPostId ?? row.existingPostId }`}>
-				投稿を開く
-			      </PrefetchLink>
-			    </Button>)}
-			{canEdit && (
-			    <Button
-				type="button"
-				variant="outline"
-				onClick={() => openRepair (row.sourceRow)}
-				disabled={busy}>
-			      編輯
-			    </Button>)}
-			{canRetry && (
-			    <Button
-				type="button"
-				onClick={() => retry (row.sourceRow)}
-				disabled={busy}>
-			      再試行
-			    </Button>)}
-		      </div>
-		    </div>
-		  </div>)})}
-	    </div>
-
-	    <div className="flex flex-col gap-2 sm:flex-row">
-	      <Button
-		  type="button"
-		  variant="outline"
-		  disabled={busy}
-		  onClick={() => {
-		      const currentSession = sessionRef.current
-		      if (currentSession == null)
-			return
-		      const nextSession = { ...currentSession, repairMode: 'all' as const }
-		      sessionRef.current = nextSession
-		      setSession (nextSession)
-		      const saved = savePostImportSession (sessionId, nextSession, message =>
-			  toast ({ title: '取込状態を保存できませんでした', description: message }))
-		      if (!(saved))
-			return
-		      navigate (`/posts/import/${ sessionId }/review`)
-		  }}>
-		確認画面へ戻る
-	      </Button>
-	      <Button
-		  type="button"
-		  variant="outline"
-		  disabled={busy}
-		  onClick={() => {
-		      clearPostImportSourceDraft (message =>
-			  toast ({ title: '入力内容を削除できませんでした', description: message }))
-		      navigate ('/posts/import')
-		  }}>
-		新しい URL リストを入力
-	      </Button>
-	    </div>
-	  </div>
-	</MainArea>)
-}
-
-export default PostImportResultPage

frontend/src/pages/posts/PostImportReviewPage.test.tsx

@@ -1,295 +1,157 @@
-import { fireEvent, render, screen, waitFor } from '@testing-library/react'
-import { HelmetProvider } from 'react-helmet-async'
-import { MemoryRouter, Route, Routes } from 'react-router-dom'
+import { fireEvent, screen, waitFor } from '@testing-library/react'
+import { useLocation } from 'react-router-dom'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
-import { loadPostImportSession, savePostImportSession } from '@/lib/postImportSession'
 import PostImportReviewPage from '@/pages/posts/PostImportReviewPage'
 import { buildUser } from '@/test/factories'
-import { buildPostImportRow } from '@/test/postImportFactories'
+import { renderWithProviders } from '@/test/render'
 
-import type { DialogueFormAction, DialogueFormControls } from '@/lib/dialogues/useDialogue'
-import type { PostImportRow } from '@/lib/postImportSession'
+import type { ReactNode } from 'react'
 
 const api = vi.hoisted (() => ({
   apiGet: vi.fn (),
   apiPost: vi.fn (),
-}))
-
-const toastApi = vi.hoisted (() => ({
-  toast: vi.fn (),
-}))
-
-const dialogue = vi.hoisted (() => ({
-  form: vi.fn (() => Promise.resolve ()),
-}))
+  isApiError: vi.fn (() => false) }))
 
 vi.mock ('@/lib/api', () => api)
-vi.mock ('@/components/ui/use-toast', () => toastApi)
-vi.mock ('@/lib/dialogues/useDialogue', () => ({
-  default: () => dialogue,
-}))
+vi.mock ('framer-motion', () => ({
+  AnimatePresence: ({ children }: { children?: ReactNode }) => <>{children}</>,
+  motion: {
+    div: ({ children }: { children?: ReactNode }) => <div>{children}</div>,
+    main: ({ children }: { children?: ReactNode }) => <main>{children}</main> } }))
+
+const metadata = (url: string, title: string) => ({
+  url,
+  title,
+  thumbnailBase: 'https://example.com/thumbnail.jpg',
+  originalCreatedFrom: '',
+  originalCreatedBefore: '',
+  duration: '',
+  tags: '',
+  parentPostIds: [],
+  fieldWarnings: { },
+  baseWarnings: [],
+  displayTags: [] })
+
+
+const LocationProbe = () => {
+  const location = useLocation ()
+  return <output aria-label="current-location">{location.pathname}{location.search}</output>
+}
+
+
+const renderReviewPage = (urls: string[]) => {
+  const search = urls.map (url => encodeURIComponent (url)).join ('+')
+  return renderWithProviders (
+      <>
+	<PostImportReviewPage user={buildUser ()}/>
+	<LocationProbe/>
+      </>,
+      { route: `/posts/new?urls=${ search }` })
+}
 
 describe ('PostImportReviewPage', () => {
   beforeEach (() => {
-    sessionStorage.clear ()
     vi.clearAllMocks ()
-    globalThis.URL.createObjectURL = vi.fn (() => 'blob:preview')
-    globalThis.URL.revokeObjectURL = vi.fn ()
-    api.apiGet.mockResolvedValue (new Blob (['img'], { type: 'image/png' }))
+    api.isApiError.mockReturnValue (false)
   })
 
-  it ('navigates to the result route after an initial recoverable failure', async () => {
-    savePostImportSession ('review-session', {
-      source: 'https://example.com/post',
-      repairMode: 'all',
-      rows: [buildPostImportRow ({ sourceRow: 1 })] })
-    api.apiPost
-        .mockResolvedValueOnce ({
-          rows: [buildPostImportRow ({ sourceRow: 1 })] })
-        .mockResolvedValueOnce ({
-          created: 0,
-          skipped: 0,
-          failed: 1,
-          rows: [{
-            sourceRow: 1,
-            status: 'failed',
-            recoverable: true,
-            errors: { title: ['invalid'] } }] })
+  it ('fetches metadata with at most four concurrent requests', async () => {
+    const resolvers: Array<(value: ReturnType<typeof metadata>) => void> = []
+    api.apiGet.mockImplementation ((_path, options) =>
+	new Promise (resolve => {
+	  resolvers.push (resolve)
+	  const url = String (options.params.url)
+	  void url
+	}))
+    const urls = Array.from (
+	{ length: 6 },
+	(_, index) => `https://example.com/${ index + 1 }`)
 
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/review-session/review']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/review"
-                  element={<PostImportReviewPage user={buildUser ()}/>}/>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<div>RESULT ROUTE</div>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
+    renderReviewPage (urls)
 
-    fireEvent.click (screen.getByRole ('button', { name: '取込実行' }))
+    await waitFor (() => expect (api.apiGet).toHaveBeenCalledTimes (4))
 
-    await waitFor (() => {
-      expect (screen.getByText ('RESULT ROUTE')).toBeInTheDocument ()
-    })
-    expect (dialogue.form).not.toHaveBeenCalled ()
+    resolvers[0]?.(metadata (urls[0]!, 'first'))
+
+    expect (await screen.findAllByText ('first')).toHaveLength (2)
+    await waitFor (() => expect (api.apiGet).toHaveBeenCalledTimes (5))
+    expect (screen.getByRole ('button', { name: '追加' })).toBeDisabled ()
+
+    for (let index = 1; index < resolvers.length; ++index)
+      resolvers[index]?.(metadata (urls[index]!, `post ${ index + 1 }`))
   })
 
-  it ('disables row editing and navigation while batch import is running', async () => {
-    let resolveValidation: ((value: { rows: PostImportRow[] }) => void) | null = null
-    savePostImportSession ('review-loading', {
-      source: 'https://example.com/post',
-      repairMode: 'all',
-      rows: [buildPostImportRow ({ sourceRow: 1 })] })
-    api.apiPost.mockImplementationOnce (() =>
-        new Promise<{ rows: PostImportRow[] }> (resolve => {
-          resolveValidation = resolve
-        }))
-    api.apiPost.mockResolvedValueOnce ({
-      created: 0,
-      skipped: 0,
-      failed: 0,
-      rows: [] })
+  it ('keeps successful rows when another metadata request fails', async () => {
+    api.apiGet
+	.mockResolvedValueOnce (metadata ('https://example.com/one', 'first'))
+	.mockRejectedValueOnce (new TypeError ('network'))
 
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/review-loading/review']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/review"
-                  element={<PostImportReviewPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    fireEvent.click (screen.getByRole ('button', { name: '取込実行' }))
+    renderReviewPage (['https://example.com/one', 'https://example.com/two'])
 
+    expect (await screen.findAllByText ('first')).toHaveLength (2)
     await waitFor (() => {
-      expect (screen.getByRole ('button', { name: '編輯' })).toBeDisabled ()
-      expect (screen.getByRole ('button', { name: 'URL リスト入力へ戻る' })).toBeDisabled ()
-      expect (screen.getByRole ('button', { name: '取込実行' })).toBeDisabled ()
+      expect (screen.getAllByText ('登録不可')).toHaveLength (2)
     })
-
-    resolveValidation?.({ rows: [buildPostImportRow ({ sourceRow: 1 })] })
+    expect (screen.getAllByRole ('button', { name: '編輯' })[0]).toBeEnabled ()
   })
 
-  it ('does not call import when validation omits a requested source row', async () => {
-    savePostImportSession ('review-missing-row', {
-      source: 'https://example.com/post-1\nhttps://example.com/post-2',
-      repairMode: 'all',
-      rows: [
-        buildPostImportRow ({ sourceRow: 1 }),
-        buildPostImportRow ({ sourceRow: 2 })] })
-    api.apiPost.mockResolvedValueOnce ({
-      rows: [buildPostImportRow ({ sourceRow: 1 })] })
+  it ('shows existing posts with Active Storage thumbnail precedence', async () => {
+    api.apiGet.mockResolvedValue ({
+      ...metadata ('https://example.com/post', ''),
+      existingPostId: 24,
+      existingPost: {
+	id: 24,
+	title: 'existing post',
+	url: 'https://example.com/post',
+	thumbnail: 'https://example.com/storage.jpg',
+	thumbnailBase: 'https://example.com/base.jpg' } })
 
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/review-missing-row/review']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/review"
-                  element={<PostImportReviewPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
+    renderReviewPage (['https://example.com/post'])
 
-    fireEvent.click (screen.getByRole ('button', { name: '取込実行' }))
+    const disclosure = await screen.findByRole ('button', {
+      name: '既存投稿による自動スキップ 1件' })
+    expect (screen.getByRole ('button', { name: '追加' })).toBeDisabled ()
 
-    await waitFor (() => {
-      expect (toastApi.toast).toHaveBeenCalledWith (
-          expect.objectContaining ({ title: '再検証結果が不完全でした' }))
-    })
-    expect (api.apiPost).toHaveBeenCalledTimes (1)
+    fireEvent.click (disclosure)
+
+    expect ((await screen.findAllByRole ('img', { name: 'サムネール' }))[0])
+	.toHaveAttribute ('src', 'https://example.com/storage.jpg')
   })
 
-  it ('does not navigate to result when import omits a requested source row', async () => {
-    savePostImportSession ('review-missing-import-row', {
-      source: 'https://example.com/post',
-      repairMode: 'all',
-      rows: [buildPostImportRow ({ sourceRow: 1 })] })
-    api.apiPost
-        .mockResolvedValueOnce ({
-          rows: [buildPostImportRow ({ sourceRow: 1 })] })
-        .mockResolvedValueOnce ({
-          created: 1,
-          skipped: 0,
-          failed: 0,
-          rows: [] })
+  it ('keeps a recoverable bulk failure on the review screen', async () => {
+    api.apiGet.mockResolvedValue (
+	metadata ('https://example.com/post', 'new post'))
+    api.apiPost.mockResolvedValue ({
+      results: [{
+	status: 'failed',
+	recoverable: true,
+	errors: { title: ['invalid title'] } }] })
 
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/review-missing-import-row/review']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/review"
-                  element={<PostImportReviewPage user={buildUser ()}/>}/>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<div>RESULT ROUTE</div>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
+    renderReviewPage (['https://example.com/post'])
 
-    fireEvent.click (screen.getByRole ('button', { name: '取込実行' }))
+    fireEvent.click (await screen.findByRole ('button', { name: '追加' }))
 
-    await waitFor (() => {
-      expect (toastApi.toast).toHaveBeenCalledWith (
-          expect.objectContaining ({ title: '登録結果が不完全でした' }))
-    })
-    expect (screen.queryByText ('RESULT ROUTE')).not.toBeInTheDocument ()
+    expect (await screen.findAllByText ('登録失敗')).toHaveLength (2)
+    expect (screen.getAllByText ('invalid title')).toHaveLength (2)
+    expect (screen.getAllByRole ('button', { name: '編輯' })[0]).toBeEnabled ()
+    expect (screen.getAllByRole ('button', { name: '再試行' })[0]).toBeEnabled ()
+    expect (screen.getByLabelText ('current-location')).toHaveTextContent ('/posts/new?')
   })
 
-  it ('keeps edited recoverable rows in session before the next batch submit', async () => {
-    savePostImportSession ('review-edit-retry', {
-      source: 'https://example.com/post',
-      repairMode: 'failed',
-      rows: [buildPostImportRow ({
-        sourceRow: 1,
-        attributes: { title: 'old title' },
-        importStatus: 'failed',
-        recoverable: true,
-        importErrors: { base: ['failed'] } })] })
-    api.apiPost
-        .mockResolvedValueOnce ({
-          rows: [buildPostImportRow ({
-            sourceRow: 1,
-            attributes: { title: 'edited title' },
-            importStatus: 'pending',
-            recoverable: true })] })
-        .mockResolvedValueOnce ({
-          rows: [buildPostImportRow ({
-            sourceRow: 1,
-            attributes: { title: 'edited title' },
-            importStatus: 'pending',
-            recoverable: true })] })
-        .mockResolvedValueOnce ({
-          created: 0,
-          skipped: 0,
-          failed: 1,
-          rows: [{
-            sourceRow: 1,
-            status: 'failed',
-            recoverable: true,
-            errors: { title: ['invalid'] } }] })
-    dialogue.form.mockImplementationOnce (async options => {
-      let actions: DialogueFormAction[] = []
-      const controls: DialogueFormControls = {
-        close: vi.fn (),
-        confirm: vi.fn (),
-        setActions: next => {
-          actions = next
-        } }
+  it ('navigates to /posts after every submitted row is created', async () => {
+    api.apiGet.mockResolvedValue (
+	metadata ('https://example.com/post', 'new post'))
+    api.apiPost.mockResolvedValue ({
+      results: [{ status: 'created', post: { id: 42 } }] })
 
-      render (options.body (controls))
-      await waitFor (() => expect (actions.length).toBe (2))
-      fireEvent.change (screen.getByDisplayValue ('old title'), {
-        target: { value: 'edited title' } })
-      await actions.find (action => action.label === '編輯内容を保存')?.onSelect ()
-    })
+    renderReviewPage (['https://example.com/post'])
 
-    render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/review-edit-retry/review']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/review"
-                  element={<PostImportReviewPage user={buildUser ()}/>}/>
-              <Route
-                  path="/posts/import/:sessionId/result"
-                  element={<div>RESULT ROUTE</div>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    fireEvent.click (screen.getByRole ('button', { name: '編輯' }))
+    fireEvent.click (await screen.findByRole ('button', { name: '追加' }))
 
     await waitFor (() => {
-      const saved = loadPostImportSession ('review-edit-retry')
-      expect (saved?.rows[0]?.attributes.title).toBe ('edited title')
-      expect (saved?.rows[0]?.importStatus).toBe ('pending')
+      expect (screen.getByLabelText ('current-location')).toHaveTextContent ('/posts')
     })
-
-    fireEvent.click (screen.getByRole ('button', { name: '取込実行' }))
-
-    await waitFor (() => {
-      expect (api.apiPost.mock.calls[1]?.[1]?.rows?.[0]?.attributes?.title)
-          .toBe ('edited title')
-    })
-  })
-
-  it ('sorts recoverable pending validation rows to the top in repair mode', () => {
-    savePostImportSession ('review-repair-sort', {
-      source: '',
-      repairMode: 'failed',
-      rows: [
-        buildPostImportRow ({
-          sourceRow: 2,
-          attributes: { title: 'normal row' } }),
-        buildPostImportRow ({
-          sourceRow: 1,
-          attributes: { title: 'repair row' },
-          importStatus: 'pending',
-          recoverable: true,
-          validationErrors: { title: ['invalid'] } })] })
-
-    const { container } = render (
-        <HelmetProvider>
-          <MemoryRouter initialEntries={['/posts/import/review-repair-sort/review']}>
-            <Routes>
-              <Route
-                  path="/posts/import/:sessionId/review"
-                  element={<PostImportReviewPage user={buildUser ()}/>}/>
-            </Routes>
-          </MemoryRouter>
-        </HelmetProvider>)
-
-    const titles = Array.from (container.querySelectorAll ('.line-clamp-2')).map (
-        node => node.textContent)
-    expect (titles[0]).toBe ('repair row')
+    expect (api.apiPost).toHaveBeenCalledWith ('/posts/bulk', expect.any (FormData))
   })
 })

frontend/src/pages/posts/PostImportSourcePage.test.tsx

@@ -1,21 +1,12 @@
-import { fireEvent, screen, waitFor } from '@testing-library/react'
+import { fireEvent, screen } from '@testing-library/react'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import PostImportSourcePage from '@/pages/posts/PostImportSourcePage'
 import { buildUser } from '@/test/factories'
-import { buildPostImportRow } from '@/test/postImportFactories'
 import { renderWithProviders } from '@/test/render'
 
-const api = vi.hoisted (() => ({
-  apiPost: vi.fn (),
-  isApiError: vi.fn () }))
-
 const router = vi.hoisted (() => ({ navigate: vi.fn () }))
 
-const toastApi = vi.hoisted (() => ({ toast: vi.fn () }))
-
-vi.mock ('@/lib/api', () => api)
-vi.mock ('@/components/ui/use-toast', () => toastApi)
 vi.mock ('react-router-dom', async importOriginal => ({
   ...await importOriginal<typeof import('react-router-dom')> (),
   useNavigate: () => router.navigate }))
@@ -24,70 +15,53 @@ describe ('PostImportSourcePage', () => {
   beforeEach (() => {
     sessionStorage.clear ()
     vi.clearAllMocks ()
-    api.isApiError.mockReturnValue (false)
   })
 
-  it ('shows no empty error initially and validates only after Next is pressed', () => {
+  it ('validates an empty source only after Next is pressed', () => {
     renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
 
     expect (screen.queryByText ('URL を入力してください．')).not.toBeInTheDocument ()
+
     fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
+
     expect (screen.getByText ('URL を入力してください．')).toBeInTheDocument ()
-    expect (api.apiPost).not.toHaveBeenCalled ()
+    expect (router.navigate).not.toHaveBeenCalled ()
   })
 
-  it ('shows frontend URL issues with line numbers without requesting preview', () => {
+  it ('reports frontend URL issues with original line numbers', () => {
     renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
     const input = screen.getByRole ('textbox', { name: '' })
 
     fireEvent.change (input, {
       target: { value: '\nftp://example.com/file\nhttps://example.com/valid' } })
-    expect (screen.queryByText (/2 行目/)).not.toBeInTheDocument ()
     fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
 
     expect (screen.getByText (/2 行目: HTTP または HTTPS/)).toBeInTheDocument ()
     expect (screen.getByText ('ftp://example.com/file')).toBeInTheDocument ()
     expect (input).toHaveAttribute ('aria-invalid', 'true')
-    expect (input.getAttribute ('aria-describedby')).toContain ('post-import-source-issues')
-    expect (api.apiPost).not.toHaveBeenCalled ()
-  })
-
-  it ('shows backend URL errors against original input without a session', async () => {
-    api.apiPost.mockResolvedValue ({
-      rows: [buildPostImportRow ({
-	sourceRow: 2,
-	url: 'https://example.com/canonical',
-	status: 'error',
-	validationErrors: { url: ['URL が重複しています．'] } })] })
-    renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
-
-    fireEvent.change (screen.getByRole ('textbox', { name: '' }), {
-      target: { value: '\nhttps://example.com/original' } })
-    fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
-
-    expect (await screen.findByText ('2 行目: URL が重複しています．')).toBeInTheDocument ()
-    expect (screen.getAllByText ('https://example.com/original')).toHaveLength (2)
     expect (router.navigate).not.toHaveBeenCalled ()
-    expect (Array.from ({ length: sessionStorage.length }, (_, index) =>
-	sessionStorage.key (index))).not.toContainEqual(
-	    expect.stringMatching (/^post-import-session:/))
   })
 
-  it ('stores a successful preview before navigating to the review route', async () => {
-    api.apiPost.mockResolvedValue ({ rows: [buildPostImportRow ()] })
+  it ('navigates with individually encoded URLs without calling an API', () => {
     renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
 
     fireEvent.change (screen.getByRole ('textbox', { name: '' }), {
-      target: { value: 'https://example.com/post' } })
+      target: {
+	value: 'https://example.com/one+a\nhttps://example.com/two?value=b+c' } })
     fireEvent.click (screen.getByRole ('button', { name: '次へ' }))
 
-    await waitFor (() => {
-      expect (router.navigate).toHaveBeenCalledWith (
-	  expect.stringMatching (/^\/posts\/import\/[^/]+\/review$/))
-    })
-    const sessionKeys = Array.from ({ length: sessionStorage.length }, (_, index) =>
-	sessionStorage.key (index)).filter (
-	    key => key?.startsWith ('post-import-session:'))
-    expect (sessionKeys).toHaveLength (1)
+    expect (router.navigate).toHaveBeenCalledWith (
+	'/posts/new?urls=https%3A%2F%2Fexample.com%2Fone%2Ba'
+	+ '+https%3A%2F%2Fexample.com%2Ftwo%3Fvalue%3Db%2Bc')
+  })
+
+  it ('disables Next when the encoded request target reaches 4096 bytes', () => {
+    renderWithProviders (<PostImportSourcePage user={buildUser ()}/>)
+    const input = screen.getByRole ('textbox', { name: '' })
+
+    fireEvent.change (input, {
+      target: { value: `https://example.com/${ 'a'.repeat (6_200) }` } })
+
+    expect (screen.getByRole ('button', { name: '次へ' })).toBeDisabled ()
   })
 })

frontend/src/pages/posts/PostImportSourcePage.tsx

@@ -11,21 +11,24 @@ import MainArea from '@/components/layout/MainArea'
 import { Button } from '@/components/ui/button'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
-import { apiPost, isApiError } from '@/lib/api'
+import {
+    buildPostNewReviewPath,
+    isPostNewReviewPathWithinLimit,
+} from '@/lib/postNewQueryState'
+import {
+    countImportSourceLines,
+    extractImportSourceUrls,
+    validateImportSource,
+} from '@/lib/postImportSourceValidation'
+import {
+    loadPostImportSourceDraft,
+    savePostImportSourceDraft,
+} from '@/lib/postImportStorage'
 import { canEditContent } from '@/lib/users'
-import { countImportSourceLines,
-	 cleanupExpiredPostImportSessions,
-	 createPostImportSessionId,
-	 initialisePreviewRows,
-	 loadPostImportSourceDraft,
-	 savePostImportSession,
-	 savePostImportSourceDraft,
-	 validateImportSource } from '@/lib/postImportSession'
 import Forbidden from '@/pages/Forbidden'
 
 import type { FC } from 'react'
 
-import type { PostImportRow } from '@/lib/postImportSession'
 import type { User } from '@/types'
 
 type Props = { user: User | null }
@@ -34,16 +37,6 @@ const MAX_ROWS = 100
 const SOURCE_ERROR_ID = 'post-import-source-error'
 const SOURCE_ISSUES_ID = 'post-import-source-issues'
 
-const urlIssuesFromRows = (rows: PostImportRow[], source: string) => {
-  const sourceLines = source.split (/\r\n|\n|\r/)
-
-  return rows.flatMap (row =>
-      (row.validationErrors.url ?? []).map (message => ({
-	  sourceRow: row.sourceRow,
-	  message,
-	  url: sourceLines[row.sourceRow - 1]?.trim () ?? row.url })))
-}
-
 
 const PostImportSourcePage: FC<Props> = ({ user }) => {
   const editable = canEditContent (user)
@@ -56,6 +49,8 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
   const editedRef = useRef (false)
 
   const lineCount = countImportSourceLines (source)
+  const sourceUrls = extractImportSourceUrls (source)
+  const withinPathLimit = isPostNewReviewPathWithinLimit (sourceUrls)
   const messages = sourceError != null ? [sourceError] : []
   const sourceDescribedBy =
       [sourceError != null ? SOURCE_ERROR_ID : null,
@@ -64,14 +59,16 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
       .join (' ')
 
   useEffect (() => {
-    cleanupExpiredPostImportSessions (message =>
-	toast ({ title: '保存済みデータを整理できませんでした', description: message }))
-
     const draft = loadPostImportSourceDraft (message =>
 	toast ({ title: '保存済み入力を復元できませんでした', description: message }))
 
     if (!(editedRef.current))
-      setSource (current => current === '' ? draft.source : current)
+      {
+	setSource (current =>
+	    current === ''
+	    ? draft.source
+	    : current)
+      }
   }, [])
 
   useEffect (() => {
@@ -104,40 +101,15 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 	setSourceError (null)
 	return
       }
+    if (!(withinPathLimit))
+      return
 
     setLoading (true)
     setSourceIssues ([])
     setSourceError (null)
     try
     {
-      const data = await apiPost<{ rows: PostImportRow[] }> ('/posts/import/preview', { source })
-      const urlIssues = urlIssuesFromRows (data.rows, source)
-      if (urlIssues.length > 0)
-	{
-	  setSourceIssues (urlIssues)
-	  return
-	}
-      const sessionId = createPostImportSessionId ()
-      const saved = savePostImportSession (
-	  sessionId,
-	  { source,
-	    rows: initialisePreviewRows (data.rows),
-	    repairMode: 'all' },
-	  message => toast ({ title: '取込状態を保存できませんでした', description: message }))
-      if (!(saved))
-	return
-      navigate (`/posts/import/${ sessionId }/review`)
-    }
-    catch (requestError)
-    {
-      const message =
-	  isApiError<{ message?: string, baseErrors?: string[] }> (requestError)
-	  ? (requestError.response?.data?.message
-	     ?? requestError.response?.data?.baseErrors?.[0])
-	  : undefined
-      setSourceError (message ?? '入力を確認してください．')
-      toast ({ title: '投稿情報の取得に失敗しました',
-	       description: message ?? '入力を確認してください．' })
+      navigate (buildPostNewReviewPath (sourceUrls))
     }
     finally
     {
@@ -146,17 +118,17 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
   }
 
   if (!(editable))
-    return <Forbidden/>
+	return <Forbidden/>
 
   return (
       <MainArea>
 	<Helmet>
-	  <title>{`投稿インポート | ${ SITE_TITLE }`}</title>
+	  <title>{`広場に投稿を追加 | ${ SITE_TITLE }`}</title>
 	</Helmet>
 
 	<Form className="max-w-4xl">
-	  <PageTitle>投稿インポート</PageTitle>
-	  <FormField label="URL リスト">
+	  <PageTitle>広場に投稿を追加</PageTitle>
+	  <FormField label="URL リスト（1 行 1 URL）">
 	    {() => (
 		<TextArea
 		    value={source}
@@ -166,8 +138,9 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 		    className="h-80 font-mono text-sm"
 		    onBlur={() => {
 		      savePostImportSourceDraft (source, message =>
-			  toast ({ title: '入力内容を保存できませんでした',
-				   description: message }))
+			  toast ({
+			      title: '入力内容を保存できませんでした',
+			      description: message }))
 		    }}
 		    onChange={ev => {
 		      editedRef.current = true
@@ -189,15 +162,15 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 		</li>))}
 	  </ul>
 
-	  <div className="flex items-center justify-between gap-3">
+	  <div className="relative z-10 flex items-center justify-between gap-3">
 	    <div className="text-sm text-neutral-600 dark:text-neutral-300">
 	      入力行数 {lineCount} / {MAX_ROWS}
 	    </div>
 	    <Button
 		type="button"
-		className="shrink-0"
+		className="pointer-events-auto shrink-0"
 		onClick={preview}
-		disabled={loading}>
+		disabled={loading || !(withinPathLimit)}>
 	      次へ
 	    </Button>
 	  </div>

frontend/src/pages/posts/PostNewPage.test.tsx

@@ -1,162 +1,40 @@
-import { fireEvent, screen, waitFor } from '@testing-library/react'
+import { screen } from '@testing-library/react'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
 
-import { toMinutePrecisionIsoUtc } from '@/components/common/DateTimeField'
 import PostNewPage from '@/pages/posts/PostNewPage'
 import { buildUser } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
 
 const api = vi.hoisted (() => ({
-  apiGet:     vi.fn (),
-  apiPost:    vi.fn (),
-  isApiError: vi.fn (),
-}))
-
-const toastApi = vi.hoisted (() => ({
-  toast: vi.fn (),
-}))
+  apiGet: vi.fn (),
+  apiPost: vi.fn (),
+  isApiError: vi.fn () }))
 
 vi.mock ('@/lib/api', () => api)
-vi.mock ('@/components/ui/use-toast', () => toastApi)
 
 describe ('PostNewPage', () => {
   beforeEach (() => {
     vi.clearAllMocks ()
     api.isApiError.mockReturnValue (false)
+    api.apiGet.mockResolvedValue ({
+      url: 'https://example.com/post',
+      title: 'post',
+      tags: '' })
+    sessionStorage.clear ()
   })
 
-  it ('blocks guests', () => {
-    renderWithProviders (<PostNewPage user={buildUser ({ role: 'guest' })}/>)
+  it ('shows the source page on /posts/new', () => {
+    renderWithProviders (<PostNewPage user={buildUser ()}/>, {
+      route: '/posts/new' })
 
-    expect (screen.getByText ('403')).toBeInTheDocument ()
+    expect (screen.getByRole ('heading', { name: '広場に投稿を追加' })).toBeInTheDocument ()
   })
 
-  it ('submits a new post with manual title and thumbnail fetch UI', async () => {
-    api.apiPost.mockResolvedValueOnce ({})
-    api.apiGet.mockResolvedValue ([])
+  it ('shows the review page when query state is present', () => {
+    renderWithProviders (<PostNewPage user={buildUser ()}/>, {
+      route: '/posts/new?urls=https%3A%2F%2Fexample.com%2Fpost' })
 
-    renderWithProviders (<PostNewPage user={buildUser ({ role: 'member' })}/>)
-
-    const textboxes = screen.getAllByRole ('textbox')
-    fireEvent.change (textboxes[0], { target: { value: 'https://example.com/post' } })
-    fireEvent.change (textboxes[1], { target: { value: '投稿タイトル' } })
-    fireEvent.change (textboxes[3], { target: { value: '1 2' } })
-    fireEvent.change (textboxes[4], { target: { value: 'tag1 tag2' } })
-    fireEvent.click (screen.getByRole ('button', { name: '追加' }))
-
-    await waitFor (() => {
-      expect (api.apiPost).toHaveBeenCalledWith (
-          '/posts',
-          expect.any (FormData),
-          { headers: { 'Content-Type': 'multipart/form-data' } },
-      )
-    })
-    const formData = api.apiPost.mock.calls[0]?.[1] as FormData
-    expect (formData.get ('url')).toBe ('https://example.com/post')
-    expect (formData.get ('title')).toBe ('投稿タイトル')
-    expect (formData.get ('parent_post_ids')).toBe ('1 2')
-    expect (formData.get ('tags')).toBe ('tag1 tag2')
-    expect (toastApi.toast).toHaveBeenCalledWith ({ title: '投稿成功!' })
-  })
-
-  it ('preserves duration while the video tag is temporarily removed', () => {
-    api.apiGet.mockResolvedValue ([])
-
-    renderWithProviders (<PostNewPage user={buildUser ({ role: 'member' })}/>)
-
-    const tags = screen.getAllByRole ('textbox')[4]
-    fireEvent.change (tags, { target: { value: '動画' } })
-    fireEvent.change (
-        screen.getByPlaceholderText ('例: 2 / 2.5 / 1:23'),
-        { target: { value: '180.5' } })
-
-    fireEvent.change (tags, { target: { value: 'general-tag' } })
-    expect (screen.queryByPlaceholderText ('例: 2 / 2.5 / 1:23')).not.toBeInTheDocument ()
-
-    fireEvent.change (tags, {
-      target: { value: '動画 general-tag' },
-    })
-    expect (screen.getByPlaceholderText ('例: 2 / 2.5 / 1:23')).toHaveValue ('180.5')
-  })
-
-  it ('shows 422 validation errors for post fields', async () => {
-    api.apiGet.mockResolvedValue ([])
-    api.isApiError.mockReturnValue (true)
-    api.apiPost.mockRejectedValueOnce ({
-      response: {
-        status: 422,
-        data:   {
-          type:        'validation_error',
-          message:     '入力内容を確認してください．',
-          errors:      { tags: ['ニコニコ・タグは直接指定できません．'] },
-          base_errors: ['投稿内容を確認してください．'],
-        },
-      },
-    })
-
-    renderWithProviders (<PostNewPage user={buildUser ({ role: 'member' })}/>)
-
-    const textboxes = screen.getAllByRole ('textbox')
-    fireEvent.change (textboxes[0], { target: { value: 'https://example.com/post' } })
-    fireEvent.change (textboxes[1], { target: { value: '投稿タイトル' } })
-    fireEvent.change (textboxes[4], { target: { value: 'nico:nico_tag' } })
-    fireEvent.click (screen.getByRole ('button', { name: '追加' }))
-
-    expect (await screen.findByText ('投稿内容を確認してください．')).toBeInTheDocument ()
-    expect (screen.getByText ('ニコニコ・タグは直接指定できません．')).toBeInTheDocument ()
-    expect (screen.getAllByRole ('textbox')[4]).toHaveAttribute ('aria-invalid', 'true')
-  })
-
-  it ('uses the shared duration, tags, and datetime value contract for post submission', async () => {
-    api.apiPost.mockResolvedValueOnce ({})
-    api.apiGet.mockResolvedValue ([])
-
-    const { container } = renderWithProviders (<PostNewPage user={buildUser ({ role: 'member' })}/>)
-
-    const textboxes = screen.getAllByRole ('textbox')
-    fireEvent.change (textboxes[0], { target: { value: 'https://example.com/post' } })
-    fireEvent.change (textboxes[1], { target: { value: '投稿タイトル' } })
-    fireEvent.change (textboxes[4], { target: { value: '動画 tag1 tag2' } })
-    fireEvent.change (
-        screen.getByPlaceholderText ('例: 2 / 2.5 / 1:23'),
-        { target: { value: '2.5' } })
-    const datetimeInputs = container.querySelectorAll ('input[type="datetime-local"]')
-    fireEvent.change (datetimeInputs[0] as HTMLInputElement, {
-      target: { value: '2024-01-01T12:34' } })
-    fireEvent.click (screen.getByRole ('button', { name: '追加' }))
-
-    await waitFor (() => expect (api.apiPost).toHaveBeenCalled ())
-
-    const formData = api.apiPost.mock.calls[0]?.[1] as FormData
-    expect (container.querySelector ('input[type="file"]')).not.toBeNull ()
-    expect (formData.get ('duration')).toBe ('2.5')
-    expect (formData.get ('tags')).toBe ('動画 tag1 tag2')
-    expect (formData.get ('original_created_from')).toBe (
-        toMinutePrecisionIsoUtc ('2024-01-01T12:34'))
-  })
-
-  it ('shows deduplicated original-created endpoint errors on the shared datetime field', async () => {
-    api.apiGet.mockResolvedValue ([])
-    api.isApiError.mockReturnValue (true)
-    api.apiPost.mockRejectedValueOnce ({
-      response: {
-        status: 422,
-        data:   {
-          type: 'validation_error',
-          errors: {
-            original_created_at: ['日時を確認してください．'],
-            original_created_from: ['日時を確認してください．'],
-            original_created_before: ['終了を確認してください．'] },
-        },
-      },
-    })
-
-    renderWithProviders (<PostNewPage user={buildUser ({ role: 'member' })}/>)
-
-    fireEvent.click (screen.getByRole ('button', { name: '追加' }))
-
-    expect (await screen.findByText ('日時を確認してください．')).toBeInTheDocument ()
-    expect (screen.getByText ('終了を確認してください．')).toBeInTheDocument ()
-    expect (screen.getAllByText ('日時を確認してください．')).toHaveLength (1)
+    expect (screen.getByRole ('heading', { name: '追加内容確認' })).toBeInTheDocument ()
+    expect (screen.queryByText ('広場に投稿を追加')).not.toBeInTheDocument ()
   })
 })

frontend/src/pages/posts/PostNewPage.tsx

@@ -1,23 +1,9 @@
-import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
-import { Helmet } from 'react-helmet-async'
-import { useNavigate } from 'react-router-dom'
+import { useMemo } from 'react'
+import { useLocation } from 'react-router-dom'
 
-import PostOriginalCreatedTimeField from '@/components/PostOriginalCreatedTimeField'
-import FieldError from '@/components/common/FieldError'
-import Form from '@/components/common/Form'
-import PageTitle from '@/components/common/PageTitle'
-import MainArea from '@/components/layout/MainArea'
-import PostDurationField from '@/components/posts/PostDurationField'
-import PostTagsField from '@/components/posts/PostTagsField'
-import PostTextField from '@/components/posts/PostTextField'
-import PostThumbnailPreview from '@/components/posts/PostThumbnailPreview'
-import { Button } from '@/components/ui/button'
-import { toast } from '@/components/ui/use-toast'
-import { SITE_TITLE } from '@/config'
-import { apiGet, apiPost } from '@/lib/api'
-import { canEditContent } from '@/lib/users'
-import { useValidationErrors } from '@/lib/useValidationErrors'
-import Forbidden from '@/pages/Forbidden'
+import PostImportReviewPage from '@/pages/posts/PostImportReviewPage'
+import PostImportSourcePage from '@/pages/posts/PostImportSourcePage'
+import { hasPostNewReviewState } from '@/lib/postNewQueryState'
 
 import type { FC } from 'react'
 
@@ -25,220 +11,16 @@ import type { User } from '@/types'
 
 type Props = { user: User | null }
 
-type PostFormField =
-    'url' | 'title' | 'tags' | 'parentPostIds'
-    | 'videoMs' | 'originalCreatedAt' | 'originalCreatedFrom'
-    | 'originalCreatedBefore' | 'thumbnail'
-
-const groupedMessages = (...values: (string[] | undefined)[]): string[] =>
-    [...new Set (values.flatMap (value => value ?? []))]
-
 
 const PostNewPage: FC<Props> = ({ user }) => {
-  const editable = canEditContent (user)
+  const location = useLocation ()
+  const reviewMode = useMemo (
+      () => hasPostNewReviewState (location.search),
+      [location.search])
 
-  const navigate = useNavigate ()
-
-  const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
-      useValidationErrors<PostFormField> ()
-
-  const [originalCreatedBefore, setOriginalCreatedBefore] =
-      useState<string | null> (null)
-  const [originalCreatedFrom, setOriginalCreatedFrom] =
-      useState<string | null> (null)
-  const [parentPostIds, setParentPostIds] = useState ('')
-  const [tags, setTags] = useState ('')
-  const [duration, setDuration] = useState ('')
-  const [thumbnailFile, setThumbnailFile] = useState<File | null> (null)
-  const [thumbnailLoading, setThumbnailLoading] = useState (false)
-  const [thumbnailPreview, setThumbnailPreview] = useState<string> ('')
-  const [title, setTitle] = useState ('')
-  const [titleLoading, setTitleLoading] = useState (false)
-  const [url, setURL] = useState ('')
-
-  const thumbnailPreviewRef = useRef ('')
-  const videoFlg =
-      useMemo (() => tags.split (/\s+/).some (tag => tag.replace (/\[.*\]$/, '') === '動画'),
-	       [tags])
-
-  const handleSubmit = async () => {
-    clearValidationErrors ()
-
-    const formData = new FormData
-    formData.append ('title', title)
-    formData.append ('url', url)
-    formData.append ('tags', tags)
-    formData.append ('parent_post_ids', parentPostIds)
-    if (videoFlg && duration !== '')
-      formData.append ('duration', duration)
-    if (thumbnailFile)
-      formData.append ('thumbnail', thumbnailFile)
-    if (originalCreatedFrom)
-      formData.append ('original_created_from', originalCreatedFrom)
-    if (originalCreatedBefore)
-      formData.append ('original_created_before', originalCreatedBefore)
-
-    try
-    {
-      await apiPost ('/posts', formData, { headers: { 'Content-Type': 'multipart/form-data' } })
-      toast ({ title: '投稿成功!' })
-      navigate ('/posts')
-    }
-    catch (e)
-    {
-      applyValidationError (e)
-      toast ({ title: '投稿失敗', description: '入力を確認してください．' })
-    }
-  }
-
-  const fetchTitle = useCallback (async () => {
-    setTitleLoading (true)
-    try
-    {
-      const data = await apiGet<{ title: string }> ('/preview/title', { params: { url } })
-      setTitle (data.title || '')
-    }
-    finally
-    {
-      setTitleLoading (false)
-    }
-  }, [url])
-
-  const fetchThumbnail = useCallback (async () => {
-    setThumbnailPreview ('')
-    setThumbnailFile (null)
-    setThumbnailLoading (true)
-    if (thumbnailPreviewRef.current)
-      URL.revokeObjectURL (thumbnailPreviewRef.current)
-    try
-    {
-      const data = await apiGet<Blob> ('/preview/thumbnail',
-				       { params: { url },
-					 responseType: 'blob' })
-      const imageURL = URL.createObjectURL (data)
-      setThumbnailPreview (imageURL)
-      setThumbnailFile (new File ([data],
-				  'thumbnail.png',
-				  { type: data.type || 'image/png' }))
-    }
-    finally
-    {
-      setThumbnailLoading (false)
-    }
-  }, [url])
-
-  useEffect (() => {
-    thumbnailPreviewRef.current = thumbnailPreview
-  }, [thumbnailPreview])
-
-  if (!(editable))
-    return <Forbidden/>
-
-  return (
-      <MainArea>
-	<Helmet>
-	  <title>{`広場に投稿を追加 | ${ SITE_TITLE }`}</title>
-	</Helmet>
-	<Form>
-	  <PageTitle>広場に投稿を追加する</PageTitle>
-	  <FieldError messages={baseErrors}/>
-
-	  <PostTextField
-	      label="URL"
-	      type="url"
-	      value={url}
-	      errors={fieldErrors.url}
-	      placeholder="例：https://www.nicovideo.jp/watch/..."
-	      onChange={setURL}/>
-
-	  <PostTextField
-	      label="タイトル"
-	      value={title}
-	      errors={fieldErrors.title}
-	      disabled={titleLoading}
-	      placeholder={titleLoading ? 'Loading...' : undefined}
-	      onChange={setTitle}
-	      after={
-		  <div className="flex flex-wrap items-center gap-2 text-sm">
-		    <span>必要なタイミングで URL から取得できます．</span>
-		    <Button
-			type="button"
-			variant="outline"
-			onClick={() => void fetchTitle ()}
-			disabled={!(url) || titleLoading}>
-		      取得
-		    </Button>
-		  </div>}/>
-
-	  <div className="space-y-2">
-	    <div className="flex flex-wrap items-center gap-2 text-sm">
-	      <span>必要なタイミングで URL から取得できます．</span>
-	      <Button
-		  type="button"
-		  variant="outline"
-		  onClick={() => void fetchThumbnail ()}
-		  disabled={!(url) || thumbnailLoading}>
-		取得
-	      </Button>
-	    </div>
-	    {thumbnailLoading && (
-		<p className="text-gray-500 text-sm">Loading...</p>)}
-	    <PostTextField
-		label="サムネール"
-		value={thumbnailFile?.name ?? ''}
-		errors={fieldErrors.thumbnail}
-		disabled
-		onChange={() => {}}/>
-	    <input
-		type="file"
-		accept="image/*"
-		onChange={e => {
-		  const file = e.target.files?.[0]
-		  if (file)
-		    {
-		      setThumbnailFile (file)
-		      setThumbnailPreview (URL.createObjectURL (file))
-		    }
-		}}/>
-	    <PostThumbnailPreview
-		url={thumbnailPreview}
-		alt="preview"
-		className="h-28 w-28"/>
-	  </div>
-
-	  <PostTextField
-	      label="親投稿"
-	      value={parentPostIds}
-	      errors={fieldErrors.parentPostIds}
-	      onChange={setParentPostIds}/>
-
-	  <PostTagsField tags={tags} setTags={setTags} errors={fieldErrors.tags}/>
-
-	  {/* オリジナルの作成日時 */}
-	  <PostOriginalCreatedTimeField
-	      originalCreatedFrom={originalCreatedFrom}
-	      setOriginalCreatedFrom={setOriginalCreatedFrom}
-	      originalCreatedBefore={originalCreatedBefore}
-	      setOriginalCreatedBefore={setOriginalCreatedBefore}
-	      errors={groupedMessages (
-		  fieldErrors.originalCreatedAt,
-		  fieldErrors.originalCreatedFrom,
-		  fieldErrors.originalCreatedBefore)}/>
-
-	  {videoFlg && (
-	      <PostDurationField
-		  value={duration}
-		  errors={fieldErrors.videoMs}
-		  onChange={setDuration}/>)}
-
-	  {/* 送信 */}
-	  <Button onClick={handleSubmit}
-		  className="px-4 py-2 bg-blue-600 text-white rounded disabled:bg-gray-400"
-		  disabled={titleLoading || thumbnailLoading}>
-	    追加
-	  </Button>
-	</Form>
-      </MainArea>)
+  return reviewMode
+      ? <PostImportReviewPage user={user}/>
+      : <PostImportSourcePage user={user}/>
 }
 
 export default PostNewPage

frontend/src/pages/tags/NicoTagListPage.test.tsx

@@ -6,7 +6,6 @@ import { dateString } from '@/lib/utils'
 import { buildTag, buildUser } from '@/test/factories'
 import { renderWithProviders } from '@/test/render'
 
-import type { ReactNode } from 'react'
 import type { NicoTag } from '@/types'
 
 const api = vi.hoisted (() => ({
@@ -27,10 +26,10 @@ const scrollIntoView = vi.fn ()
 
 vi.mock ('@/lib/api', () => api)
 vi.mock ('@/components/ui/use-toast', () => toastApi)
-vi.mock ('@/components/dialogues/DialogueProvider', () => ({
-  default: ({ children }: { children: ReactNode }) => <>{children}</>,
-  useDialogue: () => dialogue,
-}))
+vi.mock ('@/components/dialogues/DialogueProvider', async importOriginal => ({
+  ...await importOriginal<
+      typeof import('@/components/dialogues/DialogueProvider')> (),
+  useDialogue: () => dialogue }))
 
 const buildNicoTag = (values: Partial<NicoTag> = {}): NicoTag => ({
     ...buildTag (),

frontend/src/pages/theatres/TheatreDetailPage.test.tsx

@@ -40,10 +40,10 @@ const postEmbed = vi.hoisted (() => ({
 
 vi.mock ('@/lib/api', () => api)
 vi.mock ('@/lib/posts', () => postsApi)
-vi.mock ('@/components/dialogues/DialogueProvider', () => ({
-  default: ({ children }: { children: ReactNode }) => <>{children}</>,
-  useDialogue: () => dialogue,
-}))
+vi.mock ('@/components/dialogues/DialogueProvider', async importOriginal => ({
+  ...await importOriginal<
+      typeof import('@/components/dialogues/DialogueProvider')> (),
+  useDialogue: () => dialogue }))
 vi.mock ('@/components/PostEmbed', () => ({
   default: (props: {
     ref?: { current: unknown }
@@ -262,7 +262,9 @@ describe ('TheatreDetailPage', () => {
     expect (postEmbed.seek).not.toHaveBeenCalledWith (0)
   })
 
-  it ('shows child tags from the post tag tree in both vertical and horizontal layouts', async () => {
+  it (
+      'shows child tags from the post tag tree in both vertical and horizontal layouts',
+      async () => {
     const childTag = buildTag ({ id: 12, name: '子タグ', category: 'general' })
     const parentTag = buildTag ({
       id:       11,
@@ -307,7 +309,7 @@ describe ('TheatreDetailPage', () => {
       expect (within (tagSection ()).getAllByRole ('link', { name: '子タグ' }))
 	.toHaveLength (1)
     })
-  })
+      })
 
   it ('does not advance host post while video length is unknown', async () => {
     api.apiPut.mockImplementation ((path: string) => {

frontend/src/pages/users/SettingPage.tsx

@@ -1197,13 +1197,9 @@ const SettingPage: FC<Props> = ({ user, setUser }) => {
   }, [hasUnsavedThemeChanges, savedThemeSlots])
 
   useEffect (() => {
-    registerUnsavedChangesSource ({
-	dirty: hasPageUnsavedChanges,
-	discard: discardAllDirtyChanges })
-
-    return () => {
-      registerUnsavedChangesSource (null)
-    }
+    return registerUnsavedChangesSource ({
+        dirty: hasPageUnsavedChanges,
+        discard: discardAllDirtyChanges })
   }, [discardAllDirtyChanges, hasPageUnsavedChanges, registerUnsavedChangesSource])
 
   useKeyboardShortcuts ({

frontend/src/test/coverage.todo.test.ts

@@ -1,10 +0,0 @@
-import { describe, it } from 'vitest'
-
-describe ('pending high-level browser coverage', () => {
-  it.todo ('adds MSW-backed API boundary tests in a follow-up issue')
-  it.todo ('covers TheatreDetailPage with timer polling, comment posting, and next-post updates')
-  it.todo ('covers NicoTagListPage linking and pagination against realistic API payloads')
-  it.todo ('covers TagDetailSidebar drag/drop parent-child editing with pointer-event fidelity')
-  it.todo ('covers TopNav desktop and mobile menu flows as browser-level integration tests')
-  it.todo ('covers full App bootstrap for user creation, user verification, and 503 handling')
-})

frontend/src/test/postImportFactories.ts

@@ -1,4 +1,4 @@
-import type { PostImportRow } from '@/lib/postImportSession'
+import type { PostImportRow } from '@/lib/postImportTypes'
 
 export const buildPostImportRow = (
     overrides: Partial<PostImportRow> = {},

frontend/src/test/render.tsx

@@ -1,7 +1,8 @@
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import { render } from '@testing-library/react'
+import { createContext, useContext, useState } from 'react'
 import { HelmetProvider } from 'react-helmet-async'
-import { MemoryRouter } from 'react-router-dom'
+import { createMemoryRouter, RouterProvider } from 'react-router-dom'
 
 import DialogueProvider from '@/components/dialogues/DialogueProvider'
 import { KeyboardShortcutsProvider } from '@/lib/useKeyboardShortcuts'
@@ -13,6 +14,20 @@ type Options = {
   route?: string
 }
 
+const TestContentContext = createContext<ReactNode> (null)
+
+
+const TestRoute = () => {
+  const children = useContext (TestContentContext)
+
+  return (
+      <UnsavedChangesGuardProvider>
+        <KeyboardShortcutsProvider>
+          {children}
+        </KeyboardShortcutsProvider>
+      </UnsavedChangesGuardProvider>)
+}
+
 export const renderWithProviders = (
     ui:       ReactElement,
     options: Options = {},
@@ -22,20 +37,23 @@ export const renderWithProviders = (
       queries: { retry: false } },
   })
 
-  const Wrapper = ({ children }: { children: ReactNode }) => (
-      <QueryClientProvider client={queryClient}>
-        <HelmetProvider>
-          <MemoryRouter initialEntries={[options.route ?? '/']}>
-            <DialogueProvider>
-              <UnsavedChangesGuardProvider>
-                <KeyboardShortcutsProvider>
-                  {children}
-                </KeyboardShortcutsProvider>
-              </UnsavedChangesGuardProvider>
-            </DialogueProvider>
-          </MemoryRouter>
-        </HelmetProvider>
-      </QueryClientProvider>)
+  const Wrapper = ({ children }: { children: ReactNode }) => {
+    const [router] = useState (() => createMemoryRouter ([{
+        path: '*',
+        element: <TestRoute/> }], {
+        initialEntries: [options.route ?? '/'] }))
+
+    return (
+	<QueryClientProvider client={queryClient}>
+	  <HelmetProvider>
+	    <DialogueProvider>
+	      <TestContentContext.Provider value={children}>
+		<RouterProvider router={router}/>
+	      </TestContentContext.Provider>
+	    </DialogueProvider>
+	  </HelmetProvider>
+	</QueryClientProvider>)
+  }
 
   return {
     queryClient,