#399

backend/app/controllers/posts_controller.rb

@@ -131,6 +131,7 @@ class PostsController < ApplicationController
           title: nil,
           thumbnail_base: nil,
           tags: nil,
+          display_tags: [],
           original_created_from: nil,
           original_created_before: nil,
           duration: nil,
@@ -153,6 +154,7 @@ class PostsController < ApplicationController
         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],
@@ -173,6 +175,7 @@ class PostsController < ApplicationController
         title: nil,
         thumbnail_base: nil,
         tags: nil,
+        display_tags: [],
         original_created_from: nil,
         original_created_before: nil,
         duration: nil,
@@ -633,6 +636,7 @@ class PostsController < ApplicationController
         :title,
         :thumbnail_base,
         :tags,
+        :display_tags,
         :parent_post_ids,
         :original_created_from,
         :original_created_before,

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

@@ -17,12 +17,12 @@ class Post < ApplicationRecord
   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
     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
@@ -225,9 +225,23 @@ class Post < ApplicationRecord
   end
 
   def self.image_for_thumbnail_upload(bytes, content_type: nil)
-    return decode_raster_thumbnail(bytes) unless svg_content_type?(content_type) || svg_document_bytes?(bytes)
+    if svg_content_type?(content_type) || svg_document_bytes?(bytes)
+      return decode_svg_thumbnail(bytes)
+    end
 
-    decode_svg_thumbnail(bytes)
+    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)
@@ -254,6 +268,18 @@ class Post < ApplicationRecord
     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 |
@@ -354,6 +380,7 @@ class Post < ApplicationRecord
                        :svg_content_type?,
                        :decode_raster_thumbnail,
                        :decode_svg_thumbnail,
+                       :raster_thumbnail_format,
                        :sanitised_svg_bytes,
                        :svg_uses_disallowed_features?,
                        :external_svg_reference?,

backend/app/representations/post_compact_repr.rb

@@ -7,20 +7,13 @@ module PostCompactRepr
   def base post
     return nil if post.nil?
 
-    {
-        id: post.id,
-        title: post.title,
-        url: post.url,
-        thumbnail_url: thumbnail_url(post) }
-  end
-
-  def thumbnail_url post
-    return nil unless post.thumbnail.attached?
-
-    Rails.application.routes.url_helpers.rails_storage_proxy_url(
-        post.thumbnail,
-        only_path: false)
-  rescue ActionController::UrlGenerationError, ArgumentError, URI::InvalidURIError
-    nil
+    PostRepr
+        .common(post)
+        .slice(
+            'id',
+            'title',
+            'url',
+            'thumbnail',
+            'thumbnail_base')
   end
 end

backend/app/representations/post_repr.rb

@@ -69,7 +69,12 @@ module PostRepr
     return nil unless post.thumbnail.attached?
 
     Rails.application.routes.url_helpers.rails_blob_url(post.thumbnail, only_path: false)
-  rescue
+  rescue ActionController::UrlGenerationError, ArgumentError, URI::InvalidURIError => e
+    Rails.logger.warn(
+        "PostRepr.thumbnail_url failed post_id=#{post.id} " \
+        "attachment_id=#{post.thumbnail.attachment&.id} " \
+        "blob_id=#{post.thumbnail.blob&.id} " \
+        "error_class=#{e.class} message=#{e.message}")
     nil
   end
 end

backend/app/services/post_create_plan.rb

@@ -12,6 +12,8 @@ class PostCreatePlan
     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)
@@ -25,6 +27,7 @@ class PostCreatePlan
         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(' '),
@@ -103,6 +106,31 @@ class PostCreatePlan
     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 =
@@ -135,6 +163,17 @@ class PostCreatePlan
     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
@@ -166,6 +205,15 @@ class PostCreatePlan
     }.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 { Post.section_literal(_1) } }
+    }.sort_by { _1[:name] }
+  end
+
   def normalise_video_ms snapshot_tag_specs
     return nil unless snapshot_tag_specs.any? { _1[:name] == VIDEO_TAG_NAME }
 

backend/app/services/post_create_preflight.rb

@@ -29,6 +29,7 @@ class PostCreatePreflight
           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],
@@ -63,6 +64,7 @@ class PostCreatePreflight
         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],

backend/app/services/post_metadata_fetcher.rb

@@ -32,6 +32,7 @@ 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 +43,24 @@ 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 +187,7 @@ class PostMetadataFetcher
   end
 
   private_class_method :platform_tags,
+                       :display_tags,
                        :original_created_range,
                        :parse_timestamp_range,
                        :parse_nanoseconds,

backend/app/services/post_thumbnail_upload_validator.rb

@@ -11,10 +11,15 @@ class PostThumbnailUploadValidator
     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)
-    raise InvalidUpload, 'サムネイル画像の形式が不正です．' if Post.svg_document_bytes?(thumbnail.read)
-    thumbnail.rewind
+    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(thumbnail, content_type: thumbnail.content_type)
+    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．'

backend/app/services/preview/thumbnail_fetcher.rb

@@ -4,10 +4,6 @@ module Preview
     RASTER_IMAGE_CONTENT_TYPES = [
       'image/jpeg', 'image/png', 'image/gif', 'image/webp'
     ].freeze
-    REMOTE_IMAGE_CONTENT_TYPES = [
-      *RASTER_IMAGE_CONTENT_TYPES,
-      'image/svg+xml'
-    ].freeze
     HTML_MAX_BYTES = 1.megabyte
     NICONICO_XML_MAX_BYTES = 256.kilobytes
 
@@ -32,7 +28,9 @@ module Preview
     def self.fetch_image_response(raw_url)
       uri, = UrlSafety.validate(raw_url)
       response = HttpFetcher.fetch(uri.to_s)
-      unless allowed_remote_image_content_type?(response.content_type) || Post.svg_document_bytes?(response.body)
+      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
 
@@ -55,7 +53,9 @@ module Preview
       return nil if url.blank?
 
       response = HttpFetcher.fetch(url)
-      return nil unless allowed_remote_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
@@ -96,13 +96,7 @@ module Preview
       nil
     end
 
-    def self.allowed_remote_image_content_type?(content_type)
-      mime_type = content_type.to_s.split(';', 2).first.downcase.strip
-      REMOTE_IMAGE_CONTENT_TYPES.include?(mime_type)
-    end
-
     private_class_method :fetch_image_or_nil, :fetch_image!,
-                         :niconico_thumbnail_url,
-                         :allowed_remote_image_content_type?
+                         :niconico_thumbnail_url
   end
 end

backend/config/environments/development.rb

@@ -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

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,
@@ -50,12 +79,13 @@ const TagLink: FC<Props> = ({ tag,
       '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) && (
+	{(linkFlg && withWiki && isFullTag (tag)) && (
 	    <span className={markerWrapClass}>
 	      {(tag.materialId != null || tag.hasWiki || tag.hasDeerjikists)
 	       ? (
@@ -118,7 +148,7 @@ const TagLink: FC<Props> = ({ tag,
 		style={{ paddingLeft: `${ (nestLevel - 1) }rem` }}>
 	      ↳
 	    </span>)}
-	{tag.matchedAlias != null && (
+	{matchedAlias != null && (
 	    <>
 	      <span
 		  title={textTitle}
@@ -126,7 +156,7 @@ const TagLink: FC<Props> = ({ tag,
 		  style={colourStyle}
 		  {...props}>
 		<ResponsiveMarqueeText
-		    text={tag.matchedAlias}
+		    text={matchedAlias}
 		    title={textTitle}
 		    truncateOnMobile={truncateOnMobile}/>
 	      </span>
@@ -156,7 +186,7 @@ const TagLink: FC<Props> = ({ tag,
 		  title={textTitle}
 		  truncateOnMobile={truncateOnMobile}/>
 	    </span>)}
-	{withCount && (
+	{(withCount && isFullTag (tag)) && (
 	    <span className={countClass}>{tag.postCount}</span>)}
       </span>)
 }

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

@@ -1,4 +1,5 @@
 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'
@@ -90,10 +91,7 @@ const PostImportRowSummary: FC<Props> = (
             <div className="truncate text-xs text-neutral-600 dark:text-neutral-300">
               {row.url}
             </div>
-            {String (row.attributes.tags ?? '') && (
-                <div className="truncate text-xs text-neutral-500 dark:text-neutral-400">
-                  {String (row.attributes.tags ?? '')}
-                </div>)}
+            <PostImportTagLinks tags={row.displayTags}/>
             <div className="text-xs text-neutral-500 dark:text-neutral-400">
               {summaryDate (row)}
             </div>
@@ -153,10 +151,7 @@ const PostImportRowSummary: FC<Props> = (
               <div className="flex flex-wrap gap-2">
                 {displayStatus != null && <PostImportStatusBadge value={displayStatus}/>}
               </div>
-              {String (row.attributes.tags ?? '') && (
-                  <div className="text-xs text-neutral-500 dark:text-neutral-400">
-                    {String (row.attributes.tags ?? '')}
-                  </div>)}
+              <PostImportTagLinks tags={row.displayTags}/>
               <div className="text-xs text-neutral-500 dark:text-neutral-400">
                 {summaryDate (row)}
               </div>

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

@@ -0,0 +1,35 @@
+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 gap-2">
+	{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 }}
+		    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/lib/postImportRows.ts

@@ -68,6 +68,10 @@ export const validatableImportRows = (rows: PostImportRow[]): PostImportRow[] =>
 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 ?? '',
@@ -243,6 +247,11 @@ 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,
@@ -316,6 +325,12 @@ 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,

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.ts

@@ -1,105 +1,6 @@
-import type { PostImportOrigin,
-	      PostImportExistingPost,
-	      PostImportResetSnapshot,
-	      PostImportRow,
-	      PostImportSession,
-	      PostImportStatus,
-	      PostImportSkipReason,
-	      StorageErrorHandler } from '@/lib/postImportTypes'
+import type { StorageErrorHandler } from '@/lib/postImportTypes'
 
-const SESSION_VERSION = 3
-const SESSION_PREFIX = 'post-import-session:'
 const SOURCE_DRAFT_KEY = 'post-import-source-draft'
-const SESSION_MAX_AGE_MS = 24 * 60 * 60 * 1000
-const MAX_SESSION_JSON_BYTES = 262_144
-const MAX_SESSION_ROWS = 100
-const MAX_SOURCE_BYTES = 262_144
-const SESSION_ID_PATTERN =
-    /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
-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 ROW_KEYS = [
-    'sourceRow',
-    'url',
-    'attributes',
-    'fieldWarnings',
-    'baseWarnings',
-    'validationErrors',
-    'importErrors',
-    'provenance',
-    'tagSources',
-    'status',
-    'skipReason',
-    'existingPostId',
-    'existingPost',
-    'metadataUrl',
-    'resetSnapshot',
-    'createdPostId',
-    'importStatus',
-    'recoverable'] as const
-const SESSION_KEYS = [
-    'version',
-    'expiresAt',
-    'source',
-    'rows',
-    'repairMode'] as const
-const textEncoder = new TextEncoder ()
-
-
-const isPlainObject = (value: unknown): value is Record<string, unknown> =>
-    typeof value === 'object' && value != null && !(Array.isArray (value))
-
-const byteLength = (value: string): number =>
-    textEncoder.encode (value).byteLength
-
-
-export const validatePostImportSessionId = (value: unknown): string | null => {
-    if (typeof value !== 'string')
-      return null
-    if (value.length > 36 || !(SESSION_ID_PATTERN.test (value)))
-      return null
-
-    return value.toLowerCase ()
-}
-
-
-const generateUuidV4FromRandomValues = (): string => {
-    const bytes = new Uint8Array (16)
-    crypto.getRandomValues (bytes)
-    bytes[6] = (bytes[6] & 0x0f) | 0x40
-    bytes[8] = (bytes[8] & 0x3f) | 0x80
-
-    const hex = Array.from (
-	bytes,
-	byte => byte.toString (16).padStart (2, '0'))
-    return [
-	hex.slice (0, 4).join (''),
-	hex.slice (4, 6).join (''),
-	hex.slice (6, 8).join (''),
-	hex.slice (8, 10).join (''),
-	hex.slice (10, 16).join ('')].join ('-')
-}
-
-
-export const generatePostImportSessionId = (): string => {
-    if (typeof crypto.randomUUID === 'function')
-      return crypto.randomUUID ()
-
-    return generateUuidV4FromRandomValues ()
-}
-
-
-const sessionKey = (sessionId: string): string => `${ SESSION_PREFIX }${ sessionId }`
 
 
 const readStorage = (
@@ -160,420 +61,6 @@ const removeStorage = (
 }
 
 
-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 === 'pending'
-    || 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' || value === 'manual'
-
-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 (!(hasOnlyKeys (value, ['url',
-			       'attributes',
-			       'provenance',
-			       'tagSources',
-			       'fieldWarnings',
-			       'baseWarnings',
-			       'metadataUrl'])))
-      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 sanitiseExistingPost = (value: unknown): PostImportExistingPost | undefined => {
-    if (value == null)
-      return undefined
-    if (!(isPlainObject (value)))
-      return undefined
-    if (!(isPositiveInteger (value.id)))
-      return undefined
-    if (typeof value.title !== 'string' || typeof value.url !== 'string')
-      return undefined
-    if (value.thumbnailUrl != null && typeof value.thumbnailUrl !== 'string')
-      return undefined
-
-    return {
-        id: Number (value.id),
-        title: value.title,
-        url: value.url,
-        thumbnailUrl: value.thumbnailUrl as string | undefined }
-}
-
-const recalculateThumbnailWarning = (row: PostImportRow): PostImportRow => {
-    const others = (row.fieldWarnings.thumbnailBase ?? []).filter (
-	key => key !== 'サムネールなし')
-    const thumbnailBasePresent =
-	typeof row.attributes.thumbnailBase === 'string'
-	&& row.attributes.thumbnailBase.trim () !== ''
-
-    return {
-        ...row,
-        fieldWarnings: {
-	    ...row.fieldWarnings,
-	    thumbnailBase:
-		thumbnailBasePresent
-		? others
-		: [...new Set ([...others, 'サムネールなし'])] } }
-}
-
-const serialiseExistingPost = (value: PostImportExistingPost | undefined) =>
-    value == null
-    ? undefined
-    : {
-	 id: value.id,
-	 title: value.title,
-	 url: value.url,
-	 thumbnailUrl: value.thumbnailUrl }
-
-const serialiseResetSnapshot = (value: PostImportResetSnapshot) => ({
-    url: value.url,
-    attributes: Object.fromEntries (
-	Object.entries (value.attributes).map (([key, entry]) => [key, entry])),
-    provenance: Object.fromEntries (
-	Object.entries (value.provenance).map (([key, entry]) => [key, entry])),
-    tagSources: {
-	automatic: value.tagSources.automatic,
-	manual: value.tagSources.manual },
-    fieldWarnings: Object.fromEntries (
-	Object.entries (value.fieldWarnings).map (([key, entry]) => [key, [...entry]])),
-    baseWarnings: [...value.baseWarnings],
-    metadataUrl: value.metadataUrl })
-
-export const serialisePostImportRow = (row: PostImportRow) => {
-    const thumbnailBaseWarnings = (() => {
-      const others = (row.fieldWarnings.thumbnailBase ?? []).filter (
-	  message => message !== 'サムネールなし')
-      const thumbnailBasePresent =
-	  typeof row.attributes.thumbnailBase === 'string'
-	  && row.attributes.thumbnailBase.trim () !== ''
-      return thumbnailBasePresent
-	  ? others
-	  : [...new Set ([...others, 'サムネールなし'])]
-    }) ()
-
-    return {
-	sourceRow: row.sourceRow,
-	url: row.url,
-	attributes: Object.fromEntries (
-	    Object.entries (row.attributes).map (([key, entry]) => [key, entry])),
-	fieldWarnings: Object.fromEntries (
-	    Object.entries ({
-		...row.fieldWarnings,
-		thumbnailBase: thumbnailBaseWarnings }).map (([key, entry]) => [key, [...entry]])),
-	baseWarnings: [...row.baseWarnings],
-	validationErrors: Object.fromEntries (
-	    Object.entries (row.validationErrors).map (([key, entry]) => [key, [...entry]])),
-	importErrors:
-	    row.importErrors == null
-	    ? undefined
-	    : Object.fromEntries (
-		Object.entries (row.importErrors).map (([key, entry]) => [key, [...entry]])),
-	provenance: Object.fromEntries (
-	    Object.entries (row.provenance).map (([key, entry]) => [key, entry])),
-	tagSources:
-	    row.tagSources == null
-	    ? undefined
-	    : {
-		automatic: row.tagSources.automatic,
-		manual: row.tagSources.manual },
-	status: row.status,
-	skipReason: row.skipReason,
-	existingPostId: row.existingPostId,
-	existingPost: serialiseExistingPost (row.existingPost),
-	metadataUrl: row.metadataUrl,
-	resetSnapshot: serialiseResetSnapshot (row.resetSnapshot),
-	createdPostId: row.createdPostId,
-	importStatus: row.importStatus,
-	recoverable: row.recoverable }
-}
-
-export const serialisePostImportRows = (rows: PostImportRow[]) =>
-    rows.map (row => serialisePostImportRow (row))
-
-export const serialisedPostImportRowsEqual = (
-    left:  PostImportRow[],
-    right: PostImportRow[],
-): boolean =>
-    JSON.stringify (serialisePostImportRows (left))
-    === JSON.stringify (serialisePostImportRows (right))
-
-
-const sanitiseRow = (value: unknown): PostImportRow | null => {
-    if (!(isPlainObject (value)))
-      return null
-    if (!(hasOnlyKeys (value, ROW_KEYS)))
-      return null
-    if (!(Number.isInteger (value.sourceRow)) || Number (value.sourceRow) <= 0)
-      return null
-    if (typeof value.url !== 'string')
-      return null
-    if (byteLength (value.url) > 20_480)
-      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,
-        existingPost: sanitiseExistingPost (value.existingPost),
-        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 sanitiseSession = (value: unknown): PostImportSession | null => {
-    if (!(isPlainObject (value)))
-      return null
-    if (!(hasOnlyKeys (value, SESSION_KEYS)))
-      return null
-    if (value.version !== SESSION_VERSION || !(Array.isArray (value.rows)))
-      return null
-    if (value.rows.length === 0 || value.rows.length > MAX_SESSION_ROWS)
-      return null
-    if (typeof value.expiresAt !== 'string' || isExpiredSession (value.expiresAt))
-      return null
-    if (typeof value.source !== 'string' || byteLength (value.source) > MAX_SOURCE_BYTES)
-      return null
-
-    const rows = value.rows.map (sanitiseRow)
-    if (rows.some (row => row == null))
-      return null
-    if ((new Set (rows.map (row => row?.sourceRow))).size !== rows.length)
-      return null
-
-    return {
-        version: SESSION_VERSION,
-        expiresAt: value.expiresAt,
-        source: value.source,
-        rows: (rows as PostImportRow[]).map (row => recalculateThumbnailWarning (row)),
-        repairMode: value.repairMode === 'failed' ? 'failed' : 'all' }
-}
-
-
-const isExpiredSession = (expiresAt: string): boolean => {
-    const value = Date.parse (expiresAt)
-    return Number.isNaN (value) || value <= Date.now ()
-}
-
-
-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 sessionId = validatePostImportSessionId (key.slice (SESSION_PREFIX.length))
-          if (sessionId == null)
-            {
-              sessionStorage.removeItem (key)
-              --i
-              continue
-            }
-
-          const raw = sessionStorage.getItem (key)
-          if (raw == null)
-            continue
-          if (byteLength (raw) > MAX_SESSION_JSON_BYTES)
-            {
-              sessionStorage.removeItem (key)
-              --i
-              continue
-            }
-
-          try
-          {
-            if (sanitiseSession (JSON.parse (raw)) == null)
-              {
-                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．')
-    }
-}
-
-
 export const loadPostImportSourceDraft = (
     onError?: StorageErrorHandler,
 ): { source: string } => {
@@ -605,71 +92,3 @@ export const clearPostImportSourceDraft = (
 ) => {
   removeStorage (SOURCE_DRAFT_KEY, onError)
 }
-
-
-export const savePostImportSession = (
-    sessionId: string,
-    session: Omit<PostImportSession, 'version' | 'expiresAt'>,
-    onError?:  StorageErrorHandler,
-): boolean => {
-    const validatedId = validatePostImportSessionId (sessionId)
-    if (validatedId == null)
-      return false
-
-    return writeStorage (
-        sessionKey (validatedId),
-        JSON.stringify ({
-            source: session.source,
-            rows: serialisePostImportRows (session.rows),
-            repairMode: session.repairMode,
-            version: SESSION_VERSION,
-            expiresAt: new Date (Date.now () + SESSION_MAX_AGE_MS).toISOString () }),
-        onError)
-}
-
-
-export const loadPostImportSession = (
-    sessionId: string,
-    onError?: StorageErrorHandler,
-): PostImportSession | null => {
-    const validatedId = validatePostImportSessionId (sessionId)
-    if (validatedId == null)
-      return null
-
-    const raw = readStorage (sessionKey (validatedId), onError)
-    if (raw == null)
-      return null
-    if (byteLength (raw) > MAX_SESSION_JSON_BYTES)
-      {
-        removeStorage (sessionKey (validatedId), onError)
-        return null
-      }
-
-    try
-    {
-      const session = sanitiseSession (JSON.parse (raw))
-      if (session == null)
-        {
-          removeStorage (sessionKey (validatedId), onError)
-          return null
-        }
-      return session
-    }
-    catch
-    {
-      removeStorage (sessionKey (validatedId), onError)
-      return null
-    }
-}
-
-
-export const clearPostImportSession = (
-    sessionId: string,
-    onError?: StorageErrorHandler,
-) => {
-    const validatedId = validatePostImportSessionId (sessionId)
-    if (validatedId == null)
-      return
-
-    removeStorage (sessionKey (validatedId), 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 =
@@ -9,9 +11,15 @@ 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[]>
@@ -22,7 +30,8 @@ export type PostImportExistingPost = {
     id:            number
     title:         string
     url:           string
-    thumbnailUrl?: string }
+    thumbnail?:    string | null
+    thumbnailBase?: string | null }
 
 export type PostImportRow = {
     sourceRow:         number
@@ -39,6 +48,7 @@ export type PostImportRow = {
     existingPostId?:   number
     existingPost?:     PostImportExistingPost
     metadataUrl?:      string
+    displayTags?:      PostImportDisplayTag[]
     resetSnapshot:     PostImportResetSnapshot
     createdPostId?:    number
     importStatus?:     PostImportStatus
@@ -69,13 +79,6 @@ export type PostImportResultRow =
 	errors?:   Record<string, string[]>
 	recoverable?: boolean }
 
-export type PostImportSession = {
-    version:     number
-    expiresAt:   string
-    source:      string
-    rows:        PostImportRow[]
-    repairMode:  PostImportRepairMode }
-
 export type PostImportSourceIssue = {
     sourceRow: number
     message:   string

frontend/src/lib/postNewQueryState.ts

@@ -1,811 +1,58 @@
-import { resultRepairMode } from '@/lib/postImportRows'
-import { validatePostImportSessionId } from '@/lib/postImportStorage'
-
-import type {
-    PostImportOrigin,
-    PostImportRepairMode,
-    PostImportRow,
-    PostImportSkipReason,
-} from '@/lib/postImportTypes'
-
-type QueryRowState = {
-  source_row:              number
-  title:                   string
-  thumbnail_base:          string
-  original_created_from:   string
-  original_created_before: string
-  video_ms:                string
-  duration:                string
-  tags:                    string
-  parent_post_ids:         string
-  manual:                  string[]
-  skip:                    PostImportSkipReason | null
-  existing_post_id:        number | null
-  import_status:           PostImportRow['importStatus'] | null
-  created_post_id:         number | null
-  recoverable:             boolean | null }
-
-type FullRowState = QueryRowState & { url: string }
-
-type MultiRowMetaState = {
-  v:    1
-  rows: EncodedRowState[] }
-
-type EncodedSkip = 'e' | 'm'
-type EncodedImportStatus = 'p' | 'c' | 's' | 'f'
-
-type EncodedRowState = {
-  n?: number
-  u?: string
-  t?: string
-  h?: string
-  f?: string
-  b?: string
-  x?: string
-  d?: string
-  g?: string
-  p?: string
-  m?: string[]
-  s?: EncodedSkip
-  e?: number
-  i?: EncodedImportStatus
-  c?: number
-  r?: boolean }
-
-type EncodedState = {
-  v:    1
-  rows: EncodedRowState[] }
-
-export type ParsedPostNewState = {
-  rows:       PostImportRow[]
-  source:     string
-  repairMode: PostImportRepairMode
-  shortcut:   boolean }
-
-export type SerialisedPostNewState = {
-  path:     string
-  complete: boolean }
-
-const BASIC_KEYS = [
-    'url',
-    'title',
-    'thumbnail_base',
-    'original_created_from',
-    'original_created_before',
-    'video_ms',
-    'duration',
-    'tags',
-    'parent_post_ids'] as const
-const STATE_KEYS = [
-    'manual',
-    'skip',
-    'existing_post_id',
-    'import_status',
-    'created_post_id',
-    'recoverable'] as const
-const SINGLE_ROW_KEYS = [...BASIC_KEYS, ...STATE_KEYS, 'session_id'] as const
-const ENCODED_ROW_KEYS = [
-    'n',
-    'u',
-    't',
-    'h',
-    'f',
-    'b',
-    'x',
-    'd',
-    'g',
-    'p',
-    'm',
-    's',
-    'e',
-    'i',
-    'c',
-    'r'] as const
-const ALLOWED_MANUAL_FIELDS = [
-    'title',
-    'thumbnailBase',
-    'originalCreatedFrom',
-    'originalCreatedBefore',
-    'duration',
-    'tags',
-    'parentPostIds'] as const
-const MAX_REGULAR_URL_LENGTH = 768
-const MAX_COMPRESSED_STATE_LENGTH = 767
-const COMPRESSED_STATE_PREFIX = 'z1.'
-const MAX_COMPRESSED_STATE_PARAM_LENGTH = 8_192
-const MAX_COMPRESSED_STATE_BYTES = 16_384
-const MAX_DECOMPRESSED_STATE_BYTES = 262_144
-const MAX_STATE_ROWS = 100
-const MAX_QUERY_STRING_BYTES = 20_480
+const POST_NEW_REVIEW_PATH_PREFIX = '/posts/new?urls='
+const MAX_POST_NEW_REVIEW_TARGET_BYTES = 4096
 
 const textEncoder = new TextEncoder ()
-const textDecoder = new TextDecoder ()
-
-const isPlainObject = (value: unknown): value is Record<string, unknown> =>
-    typeof value === 'object' && value != null && !(Array.isArray (value))
-
-const hasOnlyKeys = (
-    value:        Record<string, unknown>,
-    allowedKeys:  readonly string[],
-): boolean =>
-    Object.keys (value).every (key => allowedKeys.includes (key))
-
-const byteLength = (value: string): number =>
-    textEncoder.encode (value).byteLength
-
-const isValidSkipReason = (value: unknown): value is PostImportSkipReason =>
-    value === 'existing' || value === 'manual'
 
 
-const isValidImportStatus = (
-    value: unknown,
-): value is PostImportRow['importStatus'] =>
-    value === 'pending'
-    || value === 'created'
-    || value === 'skipped'
-    || value === 'failed'
-
-
-const encodeSkip = (
-    value: PostImportSkipReason | null,
-): EncodedSkip | undefined =>
-    value === 'existing'
-    ? 'e'
-    : value === 'manual'
-      ? 'm'
-      : undefined
-
-
-const decodeSkip = (
-    value: unknown,
-): PostImportSkipReason | null => {
-  if (value == null)
+const rawUrlsParam = (search: string): string | null => {
+  const query = search.startsWith ('?') ? search.slice (1) : search
+  if (query === '')
     return null
-  if (value === 'e')
-    return 'existing'
-  if (value === 'm')
-    return 'manual'
+
+  for (const segment of query.split ('&'))
+    {
+      if (segment === 'urls')
+        return ''
+      if (segment.startsWith ('urls='))
+        return segment.slice ('urls='.length)
+    }
+
   return null
 }
 
 
-const encodeImportStatus = (
-    value: PostImportRow['importStatus'] | null,
-): EncodedImportStatus | undefined =>
-    value === 'pending'
-    ? 'p'
-    : value === 'created'
-      ? 'c'
-      : value === 'skipped'
-        ? 's'
-        : value === 'failed'
-          ? 'f'
-          : undefined
+export const buildPostNewReviewPath = (urls: string[]): string =>
+    `${ POST_NEW_REVIEW_PATH_PREFIX }${ urls.map (url => encodeURIComponent (url)).join ('+') }`
 
 
-const decodeImportStatus = (
-    value: unknown,
-): PostImportRow['importStatus'] | null => {
-  if (value == null)
-    return null
-  if (value === 'p')
-    return 'pending'
-  if (value === 'c')
-    return 'created'
-  if (value === 's')
-    return 'skipped'
-  if (value === 'f')
-    return 'failed'
-  return null
-}
+export const postNewReviewPathByteLength = (urls: string[]): number =>
+    textEncoder.encode (buildPostNewReviewPath (urls)).byteLength
 
 
-const parsePositiveInt = (value: string | null): number | null => {
-  if (value == null || value === '')
-    return null
-
-  const parsed = Number.parseInt (value, 10)
-  return Number.isInteger (parsed) && parsed > 0 ? parsed : null
-}
+export const isPostNewReviewPathWithinLimit = (urls: string[]): boolean =>
+    postNewReviewPathByteLength (urls) < MAX_POST_NEW_REVIEW_TARGET_BYTES
 
 
-const decodeBase64UrlBytes = (value: string): Uint8Array | null => {
+export const parsePostNewReviewUrls = (search: string): string[] => {
+  const raw = rawUrlsParam (search)
+  if (raw == null)
+    return []
+
+  return raw
+      .split ('+')
+      .filter (segment => segment !== '')
+      .map (segment => {
         try
         {
-    const padded = value.replaceAll ('-', '+').replaceAll ('_', '/')
-    const remainder = padded.length % 4
-    const base64 =
-        remainder === 0
-        ? padded
-        : `${ padded }${ '='.repeat (4 - remainder) }`
-    const binary = window.atob (base64)
-    return Uint8Array.from (binary, char => char.charCodeAt (0))
+          return decodeURIComponent (segment)
         }
         catch
         {
-    return null
+          return segment
         }
-}
-
-
-const encodeBase64UrlBytes = (value: Uint8Array): string => {
-  const binary = Array.from (value, byte => String.fromCharCode (byte)).join ('')
-  return window.btoa (binary).replaceAll ('+', '-').replaceAll ('/', '_').replaceAll ('=', '')
-}
-
-
-const compressBytes = async (value: Uint8Array): Promise<Uint8Array> => {
-  const stream =
-      new Blob ([value]).stream ().pipeThrough (new CompressionStream ('gzip'))
-  return new Uint8Array (await new Response (stream).arrayBuffer ())
-}
-
-
-const decompressBytes = async (value: Uint8Array): Promise<Uint8Array> => {
-  const stream =
-      new Blob ([value]).stream ().pipeThrough (new DecompressionStream ('gzip'))
-  const bytes = new Uint8Array (await new Response (stream).arrayBuffer ())
-  if (bytes.byteLength > MAX_DECOMPRESSED_STATE_BYTES)
-    throw new Error ('decompressed state too large')
-  return bytes
-}
-
-
-const decodeCompressedState = async (value: string): Promise<string | null> => {
-  if (!(value.startsWith (COMPRESSED_STATE_PREFIX)))
-    return null
-  if (value.length > MAX_COMPRESSED_STATE_PARAM_LENGTH)
-    return null
-
-  const encoded = value.slice (COMPRESSED_STATE_PREFIX.length)
-  const compressed = decodeBase64UrlBytes (encoded)
-  if (compressed == null)
-    return null
-  if (compressed.byteLength > MAX_COMPRESSED_STATE_BYTES)
-    return null
-
-  try
-  {
-    return textDecoder.decode (await decompressBytes (compressed))
-  }
-  catch
-  {
-    return null
-  }
-}
-
-
-const encodeCompressedState = async (value: string): Promise<string> => {
-  const compressed = await compressBytes (textEncoder.encode (value))
-  return `${ COMPRESSED_STATE_PREFIX }${ encodeBase64UrlBytes (compressed) }`
-}
-
-
-const manualFields = (row: PostImportRow): string[] =>
-    ['title',
-     'thumbnailBase',
-     'originalCreatedFrom',
-     'originalCreatedBefore',
-     'duration',
-     'tags',
-     'parentPostIds']
-    .filter (field => row.provenance[field] === 'manual')
-
-
-const baseRowState = (row: PostImportRow): QueryRowState => ({
-    source_row: row.sourceRow,
-    title: String (row.attributes.title ?? ''),
-    thumbnail_base: String (row.attributes.thumbnailBase ?? ''),
-    original_created_from: String (row.attributes.originalCreatedFrom ?? ''),
-    original_created_before: String (row.attributes.originalCreatedBefore ?? ''),
-    video_ms: String (row.attributes.videoMs ?? ''),
-    duration: String (row.attributes.duration ?? ''),
-    tags: String (row.attributes.tags ?? ''),
-    parent_post_ids: String (row.attributes.parentPostIds ?? ''),
-    manual: manualFields (row),
-    skip: row.skipReason ?? null,
-    existing_post_id: row.existingPostId ?? null,
-    import_status: row.importStatus ?? null,
-    created_post_id: row.createdPostId ?? null,
-    recoverable: row.recoverable ?? null })
-
-
-const buildRow = (state: FullRowState): PostImportRow => {
-  const manual = new Set (state.manual)
-  const provenance: Record<string, PostImportOrigin> = {
-      url: 'manual',
-      title: manual.has ('title') ? 'manual' : 'automatic',
-      thumbnailBase: manual.has ('thumbnailBase') ? 'manual' : 'automatic',
-      originalCreatedFrom: manual.has ('originalCreatedFrom') ? 'manual' : 'automatic',
-      originalCreatedBefore: manual.has ('originalCreatedBefore') ? 'manual' : 'automatic',
-      videoMs: manual.has ('duration') ? 'manual' : 'automatic',
-      duration: manual.has ('duration') ? 'manual' : 'automatic',
-      tags: manual.has ('tags') ? 'manual' : 'automatic',
-      parentPostIds: manual.has ('parentPostIds') ? 'manual' : 'automatic' }
-  const tagSources = provenance.tags === 'manual'
-      ? { automatic: '', manual: state.tags }
-      : { automatic: state.tags, manual: '' }
-  const attributes = {
-      title: state.title,
-      thumbnailBase: state.thumbnail_base,
-      originalCreatedFrom: state.original_created_from,
-      originalCreatedBefore: state.original_created_before,
-      videoMs: manual.has ('duration') ? '' : state.video_ms,
-      duration: state.duration,
-      tags: state.tags,
-      parentPostIds: state.parent_post_ids }
-
-  return {
-      sourceRow: state.source_row,
-      url: state.url,
-      attributes,
-      fieldWarnings: { },
-      baseWarnings: [],
-      validationErrors: { },
-      provenance,
-      tagSources,
-      status: 'pending',
-      skipReason: state.skip ?? undefined,
-      existingPostId: state.existing_post_id ?? undefined,
-      resetSnapshot: {
-	  url: state.url,
-	  attributes: { ...attributes },
-	  provenance: { ...provenance },
-	  tagSources: { ...tagSources },
-	  fieldWarnings: { },
-	  baseWarnings: [] },
-      createdPostId: state.created_post_id ?? undefined,
-      importStatus: state.import_status ?? undefined,
-      recoverable: state.recoverable ?? undefined }
-}
-
-
-const parseManual = (value: string | null): string[] =>
-    (value ?? '')
-    .split (',')
-    .map (entry => entry.trim ())
-    .filter (entry => entry !== '')
-
-
-const hasOnlyAllowedManualFields = (value: string[]): boolean =>
-    value.every (field => ALLOWED_MANUAL_FIELDS.includes (field as never))
-
-
-const isStringArray = (value: unknown): value is string[] =>
-    Array.isArray (value) && value.every (entry => typeof entry === 'string')
-
-
-const parseEncodedRow = (
-    value:      unknown,
-    requireUrl: boolean,
-): FullRowState | null => {
-  if (!(isPlainObject (value)))
-    return null
-
-  const row = value as Record<string, unknown>
-  if (!(hasOnlyKeys (row, ENCODED_ROW_KEYS)))
-    return null
-  const url = row['u']
-  const manual = row['m']
-  const skip = decodeSkip (row['s'])
-  const importStatus = decodeImportStatus (row['i'])
-  const existingPostId = row['e']
-  const createdPostId = row['c']
-  const recoverable = row['r']
-  const sourceRow = row['n']
-
-  if (requireUrl && typeof url !== 'string')
-    return null
-  if (typeof url === 'string' && byteLength (url) > MAX_QUERY_STRING_BYTES)
-    return null
-  if (manual != null && !(isStringArray (manual)))
-    return null
-  if ((manual ?? []).some (field => !(ALLOWED_MANUAL_FIELDS.includes (field as never))))
-    return null
-  if (row['s'] != null && skip == null)
-    return null
-  if (row['i'] != null && importStatus == null)
-    return null
-  if (existingPostId != null
-      && !(typeof existingPostId === 'number'
-           && Number.isInteger (existingPostId)
-           && existingPostId > 0))
-    return null
-  if (createdPostId != null
-      && !(typeof createdPostId === 'number'
-           && Number.isInteger (createdPostId)
-           && createdPostId > 0))
-    return null
-  if (recoverable != null && typeof recoverable !== 'boolean')
-    return null
-  if (sourceRow != null
-      && !(typeof sourceRow === 'number'
-           && Number.isInteger (sourceRow)
-           && sourceRow > 0))
-    return null
-
-  const stringFields = [
-      ['t', 'title'],
-      ['h', 'thumbnail_base'],
-      ['f', 'original_created_from'],
-      ['b', 'original_created_before'],
-      ['x', 'video_ms'],
-      ['d', 'duration'],
-      ['g', 'tags'],
-      ['p', 'parent_post_ids']] as const
-  let parsedStrings: Record<(typeof stringFields)[number][1], string>
-  try
-  {
-    parsedStrings = Object.fromEntries (
-	stringFields.map (([key, target]) => {
-	  const fieldValue = row[key]
-	  if (fieldValue != null && typeof fieldValue !== 'string')
-	    throw new Error ('invalid row')
-	  if (typeof fieldValue === 'string' && byteLength (fieldValue) > MAX_QUERY_STRING_BYTES)
-	    throw new Error ('invalid row')
-	  return [target, fieldValue ?? '']
-	}),
-    ) as Record<(typeof stringFields)[number][1], string>
-  }
-  catch
-  {
-    return null
-  }
-
-  return {
-      source_row:
-          typeof sourceRow === 'number'
-          ? sourceRow
-          : 1,
-      url: typeof url === 'string' ? url : '',
-      title: parsedStrings.title,
-      thumbnail_base: parsedStrings.thumbnail_base,
-      original_created_from: parsedStrings.original_created_from,
-      original_created_before: parsedStrings.original_created_before,
-      video_ms: parsedStrings.video_ms,
-      duration: parsedStrings.duration,
-      tags: parsedStrings.tags,
-      parent_post_ids: parsedStrings.parent_post_ids,
-      manual: manual ?? [],
-      skip,
-      existing_post_id: existingPostId ?? null,
-      import_status: importStatus,
-      created_post_id: createdPostId ?? null,
-      recoverable: recoverable ?? null }
-}
-
-
-const parseSingleRow = (params: URLSearchParams): ParsedPostNewState | null => {
-  const url = params.get ('url')
-  if (url == null || url === '')
-    return null
-  if (byteLength (url) > MAX_QUERY_STRING_BYTES)
-    return null
-
-  const hasOnlyUrl = Array.from (params.keys ()).every (
-      key => key === 'url' || key === 'session_id')
-  if (hasOnlyUrl)
-    {
-      const row = buildRow ({
-	  source_row: 1,
-	  url,
-	  title: '',
-	  thumbnail_base: '',
-	  original_created_from: '',
-	  original_created_before: '',
-	  video_ms: '',
-	  duration: '',
-	  tags: '',
-	  parent_post_ids: '',
-	  manual: [],
-	  skip: null,
-	  existing_post_id: null,
-	  import_status: null,
-	  created_post_id: null,
-	  recoverable: null })
-      return {
-	  rows: [row],
-	  source: url,
-	  repairMode: 'all',
-	  shortcut: true }
-    }
-
-  if (!(Array.from (params.keys ()).every (key => SINGLE_ROW_KEYS.includes (key as never))))
-    return null
-
-  const skipValue = params.get ('skip')
-  const importStatus = params.get ('import_status')
-  const recoverable =
-      params.get ('recoverable') == null
-      ? null
-      : params.get ('recoverable') === 'true'
-  if (skipValue != null && !(isValidSkipReason (skipValue)))
-    return null
-  if (importStatus != null && !(isValidImportStatus (importStatus)))
-    return null
-  if (!(hasOnlyAllowedManualFields (parseManual (params.get ('manual')))))
-    return null
-
-  const row = buildRow ({
-      source_row: 1,
-      url,
-      title: params.get ('title') ?? '',
-      thumbnail_base: params.get ('thumbnail_base') ?? '',
-      original_created_from: params.get ('original_created_from') ?? '',
-      original_created_before: params.get ('original_created_before') ?? '',
-      video_ms: params.get ('video_ms') ?? '',
-      duration: params.get ('duration') ?? '',
-      tags: params.get ('tags') ?? '',
-      parent_post_ids: params.get ('parent_post_ids') ?? '',
-      manual: parseManual (params.get ('manual')),
-      skip: skipValue,
-      existing_post_id: parsePositiveInt (params.get ('existing_post_id')),
-      import_status: importStatus,
-      created_post_id: parsePositiveInt (params.get ('created_post_id')),
-      recoverable })
-
-  return {
-      rows: [row],
-      source: url,
-      repairMode: resultRepairMode ([row]),
-      shortcut: false }
-}
-
-
-const parseMetaRows = (
-    urlsValue: string,
-    metaValue: string,
-): ParsedPostNewState | null => {
-  const decodedBytes = decodeBase64UrlBytes (metaValue)
-  if (decodedBytes == null)
-    return null
-
-  let parsed: MultiRowMetaState
-  try
-  {
-    parsed = JSON.parse (textDecoder.decode (decodedBytes)) as MultiRowMetaState
-  }
-  catch
-  {
-    return null
-  }
-
-  if (parsed.v !== 1 || !(Array.isArray (parsed.rows)))
-    return null
-
-  const urls = urlsValue.split (' ').filter (url => url !== '')
-  if (urls.length < 2
-      || urls.length > MAX_STATE_ROWS
-      || urls.length !== parsed.rows.length
-      || parsed.rows.length > MAX_STATE_ROWS)
-    return null
-  if (urls.some (url => byteLength (url) > MAX_QUERY_STRING_BYTES))
-    return null
-
-  const fullRows = parsed.rows.map ((row, index) => {
-    const parsedRow = parseEncodedRow (row, false)
-    return parsedRow == null
-        ? null
-        : { ...parsedRow, url: urls[index] ?? '' }
       })
-  if (fullRows.some (row => row == null))
-    return null
-  if ((new Set (fullRows.map (row => (row as FullRowState).source_row))).size !== fullRows.length)
-    return null
-
-  const rows = fullRows.map (row => buildRow (row as FullRowState))
-  return {
-      rows,
-      source: urls.join ('\n'),
-      repairMode: resultRepairMode (rows),
-      shortcut: false }
 }
 
 
-const parseFullState = async (stateValue: string): Promise<ParsedPostNewState | null> => {
-  const decoded = await decodeCompressedState (stateValue)
-  if (decoded == null)
-    return null
-
-  let parsed: EncodedState
-  try
-  {
-    parsed = JSON.parse (decoded) as EncodedState
-  }
-  catch
-  {
-    return null
-  }
-
-  if (parsed.v !== 1
-      || !(Array.isArray (parsed.rows))
-      || parsed.rows.length === 0
-      || parsed.rows.length > MAX_STATE_ROWS)
-    return null
-
-  const fullRows = parsed.rows.map (row => parseEncodedRow (row, true))
-  if (fullRows.some (row => row == null))
-    return null
-  if ((new Set (fullRows.map (row => (row as FullRowState).source_row))).size !== fullRows.length)
-    return null
-
-  const rows = fullRows.map (row => buildRow (row as FullRowState))
-  return {
-      rows,
-      source: rows.map (row => row.url).join ('\n'),
-      repairMode: resultRepairMode (rows),
-      shortcut: false }
-}
-
-
-const regularQuery = (rows: PostImportRow[]): URLSearchParams => {
-  if (rows.length === 1)
-    {
-      const row = rows[0]
-      const params = new URLSearchParams ()
-      params.set ('url', row?.url ?? '')
-      params.set ('title', String (row?.attributes.title ?? ''))
-      params.set ('thumbnail_base', String (row?.attributes.thumbnailBase ?? ''))
-      params.set ('original_created_from', String (row?.attributes.originalCreatedFrom ?? ''))
-      params.set ('original_created_before', String (row?.attributes.originalCreatedBefore ?? ''))
-      params.set ('video_ms', String (row?.attributes.videoMs ?? ''))
-      params.set ('duration', String (row?.attributes.duration ?? ''))
-      params.set ('tags', String (row?.attributes.tags ?? ''))
-      params.set ('parent_post_ids', String (row?.attributes.parentPostIds ?? ''))
-      const manual = manualFields (row).join (',')
-      if (manual !== '')
-	params.set ('manual', manual)
-      if (row.skipReason != null)
-	params.set ('skip', row.skipReason)
-      if (row.existingPostId != null)
-	params.set ('existing_post_id', String (row.existingPostId))
-      if (row.importStatus != null)
-	params.set ('import_status', row.importStatus)
-      if (row.createdPostId != null)
-	params.set ('created_post_id', String (row.createdPostId))
-      if (row.recoverable != null)
-	params.set ('recoverable', row.recoverable ? 'true' : 'false')
-      return params
-    }
-
-  const params = new URLSearchParams ()
-  params.set ('urls', rows.map (row => row.url).join (' '))
-  params.set ('meta', encodeBase64UrlBytes (textEncoder.encode (JSON.stringify ({
-      v: 1,
-      rows: rows.map (row => encodeRowState (row, false)) }))))
-  return params
-}
-
-
-const encodeRowState = (
-    row:          PostImportRow,
-    includeUrl:   boolean,
-): EncodedRowState => {
-  const base = baseRowState (row)
-  const encoded: EncodedRowState = includeUrl ? { u: row.url } : { }
-
-  encoded.n = base.source_row
-  if (base.title !== '')
-    encoded.t = base.title
-  if (base.thumbnail_base !== '')
-    encoded.h = base.thumbnail_base
-  if (base.original_created_from !== '')
-    encoded.f = base.original_created_from
-  if (base.original_created_before !== '')
-    encoded.b = base.original_created_before
-  if (base.video_ms !== '')
-    encoded.x = base.video_ms
-  if (base.duration !== '')
-    encoded.d = base.duration
-  if (base.tags !== '')
-    encoded.g = base.tags
-  if (base.parent_post_ids !== '')
-    encoded.p = base.parent_post_ids
-  if (base.manual.length > 0)
-    encoded.m = [...base.manual]
-  if (base.skip != null)
-    encoded.s = encodeSkip (base.skip)
-  if (base.existing_post_id != null)
-    encoded.e = base.existing_post_id
-  if (base.import_status != null)
-    encoded.i = encodeImportStatus (base.import_status)
-  if (base.created_post_id != null)
-    encoded.c = base.created_post_id
-  if (base.recoverable != null)
-    encoded.r = base.recoverable
-
-  return encoded
-}
-
-
-const encodeStateRows = (rows: PostImportRow[]): EncodedState => ({
-    v: 1,
-    rows: rows.map (row => encodeRowState (row, true)) })
-
-
-export const hasPostNewReviewState = (search: string): boolean => {
-  const params = new URLSearchParams (search)
-  return params.has ('state')
-      || params.has ('urls')
-      || params.has ('meta')
-      || params.has ('url')
-      || parsePostNewSessionId (search) != null
-}
-
-
-export const parsePostNewSessionId = (search: string): string | null =>
-    validatePostImportSessionId (
-        new URLSearchParams (search).get ('session_id'))
-
-
-export const appendPostNewSessionId = (
-    path:       string,
-    sessionId:  string,
-): string => {
-  const validatedId = validatePostImportSessionId (sessionId)
-  if (validatedId == null)
-    return path
-
-  const separator = path.includes ('?') ? '&' : '?'
-  return `${ path }${ separator }session_id=${ validatedId }`
-}
-
-
-export const parsePostNewState = async (
-    search: string,
-): Promise<ParsedPostNewState | null> => {
-  const params = new URLSearchParams (search)
-  const stateValue = params.get ('state')
-  if (stateValue != null)
-    return await parseFullState (stateValue)
-
-  const urlsValue = params.get ('urls')
-  const metaValue = params.get ('meta')
-  if (urlsValue != null || metaValue != null)
-    {
-      if (urlsValue == null || metaValue == null)
-	return null
-      return parseMetaRows (urlsValue, metaValue)
-    }
-
-  return parseSingleRow (params)
-}
-
-
-const serialiseCompressedRows = async (
-    rows: PostImportRow[],
-): Promise<SerialisedPostNewState | null> => {
-  try
-  {
-    for (let count = rows.length; count > 0; --count)
-      {
-	const nextRows = rows.slice (0, count)
-	const encoded = encodeStateRows (nextRows)
-	const state = await encodeCompressedState (JSON.stringify (encoded))
-	const path = `/posts/new?state=${ state }`
-	if (path.length <= MAX_COMPRESSED_STATE_LENGTH)
-	  return {
-	      path,
-	      complete: count === rows.length }
-      }
-  }
-  catch
-  {
-  }
-
-  return null
-}
-
-
-export const serialisePostNewState = async (
-    rows: PostImportRow[],
-): Promise<SerialisedPostNewState | null> => {
-  const regular = regularQuery (rows).toString ()
-  const regularPath = `/posts/new?${ regular }`
-  if (regularPath.length < MAX_REGULAR_URL_LENGTH)
-    return {
-	path: regularPath,
-	complete: true }
-
-  return await serialiseCompressedRows (rows)
-}
+export const hasPostNewReviewState = (search: string): boolean =>
+    rawUrlsParam (search) != null

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, useLocation } from 'react-router-dom'
 
-import { useDialogue } from '@/components/dialogues/DialogueProvider'
+import { useDialogue } from '@/lib/dialogues/useDialogue'
 
 import type { FC, PropsWithChildren } from 'react'
 
@@ -8,12 +17,17 @@ 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> }
+    confirmDiscardNavigation:      () => Promise<boolean>
+    allowNextNavigation:           () => void }
 
 const UnsavedChangesGuardContext =
     createContext<UnsavedChangesGuardContextValue | null> (null)
@@ -21,7 +35,9 @@ const UnsavedChangesGuardContext =
 
 export const UnsavedChangesGuardProvider: FC<PropsWithChildren> = ({ children }) => {
   const dialogue = useDialogue ()
+  const location = useLocation ()
   const [source, setSource] = useState<UnsavedChangesSource | null> (null)
+  const bypassNextNavigationRef = useRef (false)
 
   const registerUnsavedChangesSource = useCallback ((
       nextSource: UnsavedChangesSource | null,
@@ -29,28 +45,81 @@ export const UnsavedChangesGuardProvider: FC<PropsWithChildren> = ({ children })
     setSource (nextSource)
   }, [])
 
+  const allowNextNavigation = useCallback (() => {
+    bypassNextNavigationRef.current = true
+  }, [])
+
   const confirmDiscardNavigation = useCallback (async (): Promise<boolean> => {
     if (!(source?.dirty))
       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',
+	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
 
+    bypassNextNavigationRef.current = true
     await source.discard ()
     return true
   }, [dialogue, source])
 
+  const blocker = useBlocker (() =>
+      source?.dirty === true && !(bypassNextNavigationRef.current))
+
+  useEffect (() => {
+    if (blocker.state !== 'blocked')
+      return
+
+    let cancelled = false
+
+    void (async () => {
+      const confirmed = await confirmDiscardNavigation ()
+      if (cancelled)
+	return
+
+      if (confirmed)
+	blocker.proceed ()
+      else
+	blocker.reset ()
+    }) ()
+
+    return () => {
+      cancelled = true
+    }
+  }, [blocker, confirmDiscardNavigation])
+
+  useEffect (() => {
+    bypassNextNavigationRef.current = false
+  }, [location.hash, location.pathname, location.search])
+
+  useEffect (() => {
+    if (!(source?.dirty))
+      return
+
+    const handleBeforeUnload = (event: BeforeUnloadEvent) => {
+      event.preventDefault ()
+      event.returnValue = ''
+    }
+
+    window.addEventListener ('beforeunload', handleBeforeUnload)
+    return () => {
+      window.removeEventListener ('beforeunload', handleBeforeUnload)
+    }
+  }, [source?.dirty])
+
   const value = useMemo<UnsavedChangesGuardContextValue> (() => ({
       hasUnsavedChanges: source?.dirty === true,
       registerUnsavedChangesSource,
       confirmDiscardNavigation,
-  }), [confirmDiscardNavigation, registerUnsavedChangesSource, source?.dirty])
+      allowNextNavigation,
+  }), [
+      allowNextNavigation,
+      confirmDiscardNavigation,
+      registerUnsavedChangesSource,
+      source?.dirty,
+  ])
 
   return (
       <UnsavedChangesGuardContext.Provider value={value}>
@@ -59,11 +128,26 @@ export const UnsavedChangesGuardProvider: FC<PropsWithChildren> = ({ children })
 }
 
 
-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．')
 
+  useEffect (() => {
+    if (options == null)
+      return
+
+    context.registerUnsavedChangesSource ({
+	dirty: options.dirty,
+	discard: options.onDiscard ?? (() => undefined) })
+
+    return () => {
+      context.registerUnsavedChangesSource (null)
+    }
+  }, [context, options?.dirty, options?.onDiscard])
+
   return context
 }

frontend/src/pages/posts/PostImportSourcePage.tsx

@@ -12,26 +12,23 @@ import { Button } from '@/components/ui/button'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import {
-    appendPostNewSessionId,
-    serialisePostNewState,
+    buildPostNewReviewPath,
+    isPostNewReviewPathWithinLimit,
 } from '@/lib/postNewQueryState'
-import { canEditContent } from '@/lib/users'
-import { countImportSourceLines,
-	 generatePostImportSessionId,
-	 cleanupExpiredPostImportSessions,
-	 initialisePreviewRows,
-	 loadPostImportSession,
+import {
+    countImportSourceLines,
+    extractImportSourceUrls,
+    validateImportSource,
+} from '@/lib/postImportSourceValidation'
+import {
     loadPostImportSourceDraft,
-	 resultRepairMode,
-	 serialisedPostImportRowsEqual,
-	 savePostImportSession,
     savePostImportSourceDraft,
-	 validateImportSource } from '@/lib/postImportSession'
+} from '@/lib/postImportStorage'
+import { canEditContent } from '@/lib/users'
 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 }
@@ -40,69 +37,6 @@ const MAX_ROWS = 100
 const SOURCE_ERROR_ID = 'post-import-source-error'
 const SOURCE_ISSUES_ID = 'post-import-source-issues'
 
-const buildInitialRows = (source: string): PostImportRow[] =>
-    source
-        .split (/\r\n|\n|\r/)
-        .map ((line, index) => ({
-            sourceRow: index + 1,
-            url: line.trim () }))
-        .filter (row => row.url !== '')
-        .map (row => ({
-            sourceRow: row.sourceRow,
-            url: row.url,
-            attributes: {
-                title: '',
-                thumbnailBase: '',
-                originalCreatedFrom: '',
-                originalCreatedBefore: '',
-                duration: '',
-                videoMs: '',
-                tags: '',
-                parentPostIds: '' },
-            fieldWarnings: { },
-            baseWarnings: [],
-            validationErrors: { },
-            provenance: {
-                url: 'manual',
-                title: 'automatic',
-                thumbnailBase: 'automatic',
-                originalCreatedFrom: 'automatic',
-                originalCreatedBefore: 'automatic',
-                duration: 'automatic',
-                videoMs: 'automatic',
-                tags: 'automatic',
-                parentPostIds: 'automatic' },
-            tagSources: {
-                automatic: '',
-                manual: '' },
-            status: 'pending' as const,
-            resetSnapshot: {
-                url: row.url,
-                attributes: {
-                    title: '',
-                    thumbnailBase: '',
-                    originalCreatedFrom: '',
-                    originalCreatedBefore: '',
-                    duration: '',
-                    videoMs: '',
-                    tags: '',
-                    parentPostIds: '' },
-                provenance: {
-                    url: 'manual',
-                    title: 'automatic',
-                    thumbnailBase: 'automatic',
-                    originalCreatedFrom: 'automatic',
-                    originalCreatedBefore: 'automatic',
-                    duration: 'automatic',
-                    videoMs: 'automatic',
-                    tags: 'automatic',
-                    parentPostIds: 'automatic' },
-                tagSources: {
-                    automatic: '',
-                    manual: '' },
-                fieldWarnings: { },
-                baseWarnings: [] } }))
-
 
 const PostImportSourcePage: FC<Props> = ({ user }) => {
   const editable = canEditContent (user)
@@ -115,6 +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,
@@ -122,13 +58,7 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
       .filter (value => value != null)
       .join (' ')
 
-  const showStorageError = (message: string) =>
-      toast ({ description: message })
-
   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 }))
 
@@ -171,73 +101,15 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 	setSourceError (null)
 	return
       }
+    if (!(withinPathLimit))
+      return
 
     setLoading (true)
     setSourceIssues ([])
     setSourceError (null)
     try
     {
-      const nextRows = initialisePreviewRows (buildInitialRows (source))
-      const serialised = await serialisePostNewState (nextRows)
-      const sessionId = (() => {
-	try
-	{
-	  return generatePostImportSessionId ()
-	}
-	catch
-	{
-	  return null
-	}
-      }) ()
-      const session = {
-	  source,
-	  rows: nextRows,
-	  repairMode: resultRepairMode (nextRows) }
-      const saved =
-	  sessionId == null
-	  ? false
-	  : savePostImportSession (sessionId, session, showStorageError)
-      const loadedSession =
-	  sessionId == null
-	  ? null
-	  : loadPostImportSession (sessionId, showStorageError)
-      const sessionRoundTripSucceeded =
-	  saved
-	  && serialisedPostImportRowsEqual (
-	      loadedSession?.rows ?? [],
-	      nextRows)
-      const canNavigate =
-	  serialised?.complete === true
-	  || sessionRoundTripSucceeded
-      if (!(canNavigate))
-	{
-	  showStorageError ('ブラウザへ保存できませんでした．')
-	  return
-	}
-
-      const nextPath = (() => {
-	if (serialised != null)
-	  {
-	    return sessionId == null
-		? serialised.path
-		: appendPostNewSessionId (serialised.path, sessionId)
-	  }
-	if (sessionRoundTripSucceeded && sessionId != null)
-	  return `/posts/new?session_id=${ sessionId }`
-	return null
-      }) ()
-      if (nextPath == null)
-	{
-	  showStorageError ('ブラウザへ保存できませんでした．')
-	  return
-	}
-
-      navigate (nextPath)
-    }
-    catch (error)
-    {
-      console.error (error)
-      showStorageError ('ブラウザへ保存できませんでした．')
+      navigate (buildPostNewReviewPath (sourceUrls))
     }
     finally
     {
@@ -256,7 +128,7 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 
 	<Form className="max-w-4xl">
 	  <PageTitle>広場に投稿を追加</PageTitle>
-	  <FormField label="URL リスト">
+	  <FormField label="URL リスト（1 行 1 URL）">
 	    {() => (
 		<TextArea
 		    value={source}
@@ -266,7 +138,8 @@ 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',
+			  toast ({
+			      title: '入力内容を保存できませんでした',
 			      description: message }))
 		    }}
 		    onChange={ev => {
@@ -297,7 +170,7 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 		type="button"
 		className="pointer-events-auto shrink-0"
 		onClick={preview}
-		disabled={loading}>
+		disabled={loading || !(withinPathLimit)}>
 	      次へ
 	    </Button>
 	  </div>