Merge branch 'main' into feature/406

backend/app/controllers/application_controller.rb

@@ -92,6 +92,4 @@ class ApplicationController < ActionController::API
 
     value
   end
-
-  def resolve_locale! = Locale.find_by(code: params[:locale]) || Locale.nipponese
 end

backend/app/controllers/deerjikists_controller.rb

@@ -1,7 +1,5 @@
 class DeerjikistsController < ApplicationController
   def show
-    locale = resolve_locale!
-
     platform = params[:platform].to_s.strip
     code = params[:code].to_s.strip
     return render_bad_request('platform は必須です．') if platform.blank?
@@ -9,10 +7,10 @@ class DeerjikistsController < ApplicationController
 
     deerjikist = Deerjikist
                  .joins(:tag)
-                 .includes(tag: :tag_names)
+                 .includes(tag: :tag_name)
                  .find_by(platform:, code:)
     if deerjikist
-      render json: DeerjikistRepr.base(deerjikist, language_code: locale.language_code)
+      render json: DeerjikistRepr.base(deerjikist)
     else
       head :not_found
     end
@@ -22,7 +20,6 @@ class DeerjikistsController < ApplicationController
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
     platform = params[:platform].to_s.strip
     code = params[:code].to_s.strip
     tag_id = params[:tag_id].to_i
@@ -35,7 +32,7 @@ class DeerjikistsController < ApplicationController
       d.save!
     end
 
-    render json: DeerjikistRepr.base(deerjikist, language_code: locale.language_code)
+    render json: DeerjikistRepr.base(deerjikist)
   end
 
   def destroy

backend/app/controllers/gekanator_posts_controller.rb

@@ -2,7 +2,7 @@ class GekanatorPostsController < ApplicationController
   def index
     posts =
         Post
-        .preload(:post_similarities, tags: :tag_names)
+        .preload(:post_similarities, tags: :tag_name)
         .with_attached_thumbnail
         .order(Arel.sql(
             'COALESCE(posts.original_created_before - INTERVAL 1 MINUTE, ' \
@@ -56,7 +56,7 @@ class GekanatorPostsController < ApplicationController
   def tag_json tag
     {
       id: tag.id,
-      name: tag.name('ja'),
+      name: tag.name,
       category: tag.category
     }
   end

backend/app/controllers/gekanator_questions_controller.rb

@@ -126,9 +126,9 @@ class GekanatorQuestionsController < ApplicationController
     end
 
     Tag
-        .joins(:tag_names)
+        .joins(:tag_name)
         .where(category: categories.uniq)
-        .where(tag_names: { language_code: 'ja', primary_flg: true, name: names.uniq })
+        .where(tag_names: { name: names.uniq })
         .where.not(deprecated_at: nil)
         .pluck('tags.category', 'tag_names.name')
         .each_with_object({ }) do |(category, name), h|

backend/app/controllers/materials_controller.rb

@@ -7,8 +7,6 @@ class MaterialsController < ApplicationController
   rescue_from MaterialZipExporter::MissingFileError, with: :render_zip_missing_file
 
   def index
-    locale = resolve_locale!
-
     page = (params[:page].presence || 1).to_i
     limit = (params[:limit].presence || 20).to_i
 
@@ -22,7 +20,7 @@ class MaterialsController < ApplicationController
     q = Material.includes(:material_export_items,
                           thumbnail_attachment: :blob,
                           file_attachment: :blob,
-                          tag: :tag_names)
+                          tag: :tag_name)
     q = q.where(tag_id: nil) if filters[:tag_state] == 'untagged'
     q = q.where.not(tag_id: nil) if filters[:tag_state] == 'tagged'
     q = apply_material_tag_filter(q, filters, tag_graph)
@@ -44,10 +42,7 @@ class MaterialsController < ApplicationController
         .offset(offset)
         .to_a
 
-    response = { materials: MaterialRepr.list_many(
+    response = { materials: MaterialRepr.list_many(materials, host: request.base_url),
-                   materials,
-                   host: request.base_url,
-                   language_code: locale.language_code),
                  count: }
     if filters[:tag_id]
       response[:tag_scope] = material_index_tag_scope(filters, tag_graph)
@@ -60,8 +55,6 @@ class MaterialsController < ApplicationController
   end
 
   def show
-    locale = resolve_locale!
-
     material =
         Material
         .includes(:tag, :material_export_items)
@@ -70,17 +63,15 @@ class MaterialsController < ApplicationController
         .find_by(id: params[:id])
     return head :not_found unless material
 
-    wiki_page_body = material.tag&.tag_name('ja')&.wiki_page&.current_revision&.body
+    wiki_page_body = material.tag&.tag_name&.wiki_page&.current_revision&.body
 
-    render json: MaterialRepr.base(material, host: request.base_url,
+    render json: MaterialRepr.base(material, host: request.base_url).merge(wiki_page_body:)
-                                   language_code: locale.language_code).merge(wiki_page_body:)
   end
 
   def create
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
     tag_name_raw = params[:tag].to_s.strip
     file = params[:file]
     file_sha256 = MaterialFileSha256.from_upload(file)
@@ -98,14 +89,13 @@ class MaterialsController < ApplicationController
 
     begin
       Material.transaction do
-        tag = resolve_material_tag!(locale, tag_name_raw)
+        tag = resolve_material_tag!(tag_name_raw)
         material = Material.new(tag:, url:,
                                 created_by_user: current_user,
                                 updated_by_user: current_user)
         material.file.attach(uploaded_blob) if uploaded_blob
         material.save!
-        TagVersioning.record_tag_snapshot!(tag, created_by_user: current_user,
+        TagVersioning.record_tag_snapshot!(tag, created_by_user: current_user)
-                                           language_code: locale.language_code)
         upsert_export_paths!(material)
         MaterialVersionRecorder.record!(material:, event_type: :create,
                                         created_by_user: current_user)
@@ -117,8 +107,7 @@ class MaterialsController < ApplicationController
 
     if material
       log_thumbnail_generation(material, MaterialThumbnailGenerator.generate!(material))
-      render json: MaterialRepr.base(material, host: request.base_url,
+      render json: MaterialRepr.base(material, host: request.base_url), status: :created
-                                     language_code: locale.language_code), status: :created
     else
       render_validation_error material
     end
@@ -143,14 +132,12 @@ class MaterialsController < ApplicationController
     block = MaterialImportBlockMatcher.match_for_sha256(file_sha256)
     return render_material_import_block(block) if block
 
-    locale = resolve_locale!
-
     uploaded_blob = build_uploaded_material_blob!(file, file_sha256)
 
     begin
       Material.transaction do
         MaterialVersionRecorder.ensure_snapshot!(material, created_by_user: current_user)
-        tag = resolve_material_tag!(locale, tag_name_raw)
+        tag = resolve_material_tag!(tag_name_raw)
         material.assign_attributes(tag:, url:, updated_by_user: current_user)
         if uploaded_blob
           material.file.attach(uploaded_blob)
@@ -158,8 +145,7 @@ class MaterialsController < ApplicationController
           material.file.detach
         end
         material.save!
-        TagVersioning.record_tag_snapshot!(tag, created_by_user: current_user,
+        TagVersioning.record_tag_snapshot!(tag, created_by_user: current_user)
-                                           language_code: locale.language_code)
         upsert_export_paths!(material)
         MaterialVersionRecorder.record!(material:, event_type: :update,
                                         created_by_user: current_user)
@@ -171,8 +157,7 @@ class MaterialsController < ApplicationController
 
     log_thumbnail_generation(material, MaterialThumbnailGenerator.generate!(material))
 
-    render json: MaterialRepr.base(material, host: request.base_url,
+    render json: MaterialRepr.base(material, host: request.base_url)
-                                   language_code: locale.language_code)
   end
 
   def destroy
@@ -251,8 +236,10 @@ class MaterialsController < ApplicationController
     nil
   end
 
-  def resolve_material_tag! locale, tag_name_raw
+  def resolve_material_tag! tag_name_raw
-    Tag.find_or_create_by_tag_name!(locale, tag_name_raw, category: :material)
+    tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
+    tag = tag_name.tag
+    tag || Tag.create!(tag_name:, category: :material)
   end
 
   def material_index_needs_tag_name? filters
@@ -266,12 +253,7 @@ class MaterialsController < ApplicationController
   end
 
   def material_index_join_tag_name q
-    q.left_joins(:tag).joins(<<~SQL.squish)
+    q.left_joins(tag: :tag_name)
-      LEFT JOIN tag_names
-        ON tag_names.tag_id = tags.id
-       AND tag_names.language_code = 'ja'
-       AND tag_names.primary_flg = TRUE
-    SQL
   end
 
   def material_index_join_file_blob q
@@ -287,11 +269,9 @@ class MaterialsController < ApplicationController
 
   def apply_material_query q, term
     like = "%#{ ActiveRecord::Base.sanitize_sql_like(term) }%"
-    q.where(<<~SQL.squish, q: like)
+    q.where('tag_names.name LIKE :q OR materials.url LIKE :q OR ' \
-      tag_names.name LIKE :q
+            'material_file_blobs.filename LIKE :q',
-      OR materials.url LIKE :q
+            q: like)
-      OR material_file_blobs.filename LIKE :q
-    SQL
   end
 
   def apply_material_media_kind q, media_kind
@@ -343,9 +323,8 @@ class MaterialsController < ApplicationController
         end
     tags_by_id =
         Tag
-        .joins(:tag_names)
+        .joins(:tag_name)
-        .where(id: scope_tag_ids,
+        .where(id: scope_tag_ids)
-               tag_names: { language_code: 'ja', primary_flg: true })
         .pluck('tags.id', 'tag_names.name', 'tags.category', 'tags.deprecated_at')
         .each_with_object({ }) do |(id, name, category, deprecated_at), hash|
           hash[id] = { id:, name:, category:, deprecated: deprecated_at.present? }

backend/app/controllers/nico_tags_controller.rb

@@ -1,7 +1,5 @@
 class NicoTagsController < ApplicationController
   def index
-    locale = resolve_locale!
-
     name = params[:name].presence
     linked_tag = params[:linked_tag].presence
     link_status = params[:link_status].presence
@@ -17,27 +15,21 @@ class NicoTagsController < ApplicationController
     limit = 1 if limit < 1
 
     post_tag_max_sql =
-        PostExternalTag
+        PostTag
-        .select('external_tag_id, MAX(created_at) AS max_created_at')
+        .select('tag_id, MAX(created_at) AS max_created_at')
-        .group('external_tag_id')
+        .group('tag_id')
         .to_sql
 
-    q =
+    q = Tag.nico_tags
-        ExternalTag
+           .joins(:tag_name)
            .joins("LEFT JOIN (#{ post_tag_max_sql }) post_tag_max " \
-               'ON post_tag_max.external_tag_id = external_tags.id')
+                  'ON post_tag_max.tag_id = tags.id')
-        .includes(linked_tags: { tag_names: :wiki_page })
+           .includes(:tag_name, tag_name: :wiki_page, linked_tags: { tag_name: :wiki_page })
-    if name
+    q = q.where('tag_names.name LIKE ?', "%#{ name }%") if name
-      q = q.where(('external_tags.name LIKE ? ' +
-                   "OR CONCAT(external_tags.platform, ':', external_tags.name) LIKE ?"),
-                  "%#{ name }%", "%#{ name }")
-    end
-
     if linked_tag
       linked_tag_ids =
         Tag
-          .joins(:tag_names)
+        .joins(:tag_name)
-          .where(tag_names: { language_code: 'ja', primary_flg: true })
         .where('tag_names.name LIKE ?', "%#{ linked_tag }%")
         .pluck(:id)
       linked_nico_tag_ids = NicoTagRelation.where(tag_id: linked_tag_ids).pluck(:nico_tag_id)
@@ -46,7 +38,7 @@ class NicoTagsController < ApplicationController
     if link_status.in?(['linked', 'unlinked'])
       exists_sql =
           'EXISTS (SELECT 1 FROM nico_tag_relations ' \
-          'WHERE nico_tag_relations.nico_tag_id = external_tags.id)'
+          'WHERE nico_tag_relations.nico_tag_id = tags.id)'
       q = link_status == 'linked' ? q.where(exists_sql) : q.where("NOT #{ exists_sql }")
     end
 
@@ -54,68 +46,54 @@ class NicoTagsController < ApplicationController
     sort_sql =
         case order[0]
         when 'name'
-          'external_tags.name'
+          'tag_names.name'
         when 'updated_at'
           'post_tag_max.max_created_at'
         else
-          "external_tags.#{ order[0] }"
+          "tags.#{ order[0] }"
         end
-    tags = q.reselect('external_tags.*',
+    tags = q.reselect('tags.*',
                       Arel.sql('post_tag_max.max_created_at AS recent_post_tag_created_at'))
-            .order(Arel.sql("#{ sort_sql } #{ order[1] }, external_tags.id #{ order[1] }"))
+            .order(Arel.sql("#{ sort_sql } #{ order[1] }, tags.id #{ order[1] }"))
             .limit(limit)
             .offset((page - 1) * limit)
             .to_a
 
     render json: { tags: tags.map { |tag|
-      external_tag_json(tag).merge(
+      TagRepr.base(tag).merge(
           recent_post_tag_created_at: tag.recent_post_tag_created_at,
-          linked_tags: tag.linked_tags.map { |lt|
+          linked_tags: tag.linked_tags.map { |lt| TagRepr.base(lt) })
-            TagRepr.base(lt, language_code: locale.language_code)
-          })
     }, count: }
   end
 
-  def show
-    tag = ExternalTag.find(params[:id])
-
-    render json: external_tag_json(tag)
-  end
-
   def update
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
-
     id = params[:id].to_i
 
-    tag = ExternalTag.find(id)
+    tag = Tag.find(id)
+    return render_bad_request('ニコニコ・タグを指定してください．') unless tag.nico?
 
     linked_tag_names = params[:tags].to_s.split
     linked_tags = nil
 
     ApplicationRecord.transaction do
-      linked_tags = Tag.normalise_tags!(locale, linked_tag_names,
+      linked_tags = Tag.normalise_tags!(linked_tag_names, with_tagme: false,
-                                        with_tagme: false,
                                                           with_no_deerjikist: false)
+      if linked_tags.any? { |t| t.nico? }
+        raise Tag::NicoTagNormalisationError
+      end
 
-      TagVersioning.record_tag_snapshots!(
+      TagVersioning.record_tag_snapshots!(linked_tags, created_by_user: current_user)
-          linked_tags,
-          created_by_user: current_user,
-          language_code: locale.language_code)
 
       tag.linked_tags = linked_tags
       tag.save!
 
-      NicoTagVersionRecorder.record!(external_tag: tag,
+      NicoTagVersionRecorder.record!(tag:, event_type: :update, created_by_user: current_user)
-                                     event_type: :update,
-                                     created_by_user: current_user)
     end
 
-    render json: tag.linked_tags.map { |t|
+    render json: tag.linked_tags.map { |t| TagRepr.base(t) }, status: :ok
-      TagRepr.base(t, language_code: locale.language_code)
-    }, status: :ok
   rescue Tag::NicoTagNormalisationError
     render_validation_error fields: { tags: ['ニコニコ・タグ同士は連携できません．'] }
   rescue ActiveRecord::RecordInvalid => e
@@ -124,21 +102,6 @@ class NicoTagsController < ApplicationController
 
   private
 
-  def external_tag_json tag
-    { id: tag.id,
-      name: "#{ tag.platform }:#{ tag.name }",
-      category: 'nico',
-      post_count: tag.post_count,
-      created_at: tag.created_at,
-      updated_at: tag.created_at,
-      deprecated_at: nil,
-      aliases: [],
-      parents: [],
-      has_wiki: false,
-      material_id: nil,
-      has_deerjikists: false }
-  end
-
   def render_nico_tag_form_record_invalid record
     if record.is_a?(TagName) || record.is_a?(Tag)
       render_validation_error fields: { tags: record.errors.full_messages.map { |message|

backend/app/controllers/post_versions_controller.rb

@@ -2,9 +2,6 @@ class PostVersionsController < ApplicationController
   def index
     post_id = params[:post].presence
     tag_id = params[:tag].presence&.to_i
-    external_tag_id = params[:external_tag].presence&.to_i
-    return head :bad_request if tag_id && external_tag_id
-
     page = (params[:page].presence || 1).to_i
     limit = (params[:limit].presence || 20).to_i
 
@@ -29,14 +26,9 @@ class PostVersionsController < ApplicationController
                 'prev.original_created_from AS prev_original_created_from',
                 'prev.original_created_before AS prev_original_created_before')
     q = q.where('post_versions.post_id = ?', post_id) if post_id
-    if external_tag_id || (tag_id && !(Tag.exists?(id: tag_id)))
+    if tag_id
-      q = q.where('JSON_CONTAINS(post_versions.tags_json,' +
+      q = q.where("JSON_CONTAINS(post_versions.tags_json, JSON_OBJECT('id', #{ tag_id })) " +
-                  "JSON_OBJECT('external_tag_id', #{ external_tag_id || tag_id })) " +
+                  "OR JSON_CONTAINS(prev.tags_json, JSON_OBJECT('id', #{ tag_id }))")
-                  'OR JSON_CONTAINS(prev.tags_json,' +
-                  "JSON_OBJECT('external_tag_id', #{ external_tag_id || tag_id }))")
-    elsif tag_id
-      q = q.where("JSON_CONTAINS(post_versions.tags_json, JSON_OBJECT('tag_id', #{ tag_id })) " +
-                  "OR JSON_CONTAINS(prev.tags_json, JSON_OBJECT('tag_id', #{ tag_id }))")
     end
 
     count = q.except(:select, :order, :limit, :offset).count
@@ -51,19 +43,50 @@ class PostVersionsController < ApplicationController
   private
 
   def serialise_versions rows
-    rows = rows.to_a
     user_ids = rows.map(&:created_by_user_id).compact.uniq
     users_by_id = User.where(id: user_ids).pluck(:id, :name).to_h
-    snapshots = rows.flat_map { |row|
-      [normalise_json(row.tags_json),
-       normalise_json(row.attributes['prev_tags_json']) || []]
-    }
-    external_tag_names = external_tag_names_for(snapshots)
 
     rows.map do |row|
-      cur_tags = snapshot_tag_literals(normalise_json(row.tags_json), external_tag_names)
+      cur_tags =
-      prev_tags = snapshot_tag_literals(
+          normalise_json(row.tags_json)
-          normalise_json(row.attributes['prev_tags_json']) || [], external_tag_names)
+          .sort_by { [(case _1.fetch('category')
+                       when 'deerjikist'
+                         0
+                       when 'meme'
+                         1
+                       when 'character'
+                         2
+                       when 'general'
+                         3
+                       when 'material'
+                         4
+                       when 'meta'
+                         5
+                       else
+                         6
+                       end),
+                      _1.fetch('name').downcase] }
+          .map { Post.tag_snapshot_literal(_1) }
+      prev_tags =
+          (normalise_json(row.attributes['prev_tags_json']) || [])
+          .sort_by { [(case _1.fetch('category')
+                       when 'deerjikist'
+                         0
+                       when 'meme'
+                         1
+                       when 'character'
+                         2
+                       when 'general'
+                         3
+                       when 'material'
+                         4
+                       when 'meta'
+                         5
+                       else
+                         6
+                       end),
+                      _1.fetch('name').downcase] }
+          .map { Post.tag_snapshot_literal(_1) }
 
       { post_id: row.post_id,
         version_no: row.version_no,
@@ -90,41 +113,7 @@ class PostVersionsController < ApplicationController
     end
   end
 
-  def external_tag_names_for snapshots
+  def build_version_tags(cur_tags, prev_tags)
-    ids = snapshots.flatten.filter_map { _1['external_tag_id'] }.uniq
-    names = ExternalTag.where(id: ids).pluck(:id, :platform, :name).to_h { |id, platform, name|
-      [id, "#{ platform }:#{ name }"]
-    }
-    missing_ids = ids - names.keys
-
-    NicoTagVersion
-        .where(tag_id: missing_ids)
-        .order(:tag_id, version_no: :desc)
-        .pluck(:tag_id, :name)
-        .each { |id, name| names[id] ||= name }
-
-    names
-  end
-
-  def snapshot_tag_literals snapshots, external_tag_names
-    snapshots
-        .filter_map { |snapshot|
-          if snapshot.key?('tag_id')
-            [tag_category_order(snapshot['category']),
-             Post.tag_snapshot_literal(snapshot)]
-          elsif external_tag_names[snapshot['external_tag_id']]
-            [6, external_tag_names[snapshot['external_tag_id']]]
-          end
-        }
-        .sort_by { |order, name| [order, name.downcase] }
-        .map(&:second)
-  end
-
-  def tag_category_order category
-    ['deerjikist', 'meme', 'character', 'general', 'material', 'meta'].index(category) || 6
-  end
-
-  def build_version_tags cur_tags, prev_tags
     (cur_tags | prev_tags).map do |name|
       type =
         if cur_tags.include?(name) && prev_tags.include?(name)
@@ -135,7 +124,10 @@ class PostVersionsController < ApplicationController
           'removed'
         end
 
-      { name:, type: }
+      {
+        name:,
+        type:
+      }
     end
   end
 end

backend/app/controllers/posts_controller.rb

@@ -7,8 +7,6 @@ class PostsController < ApplicationController
   end
 
   def index
-    locale = resolve_locale!
-
     url = params[:url].presence
     title = params[:title].presence
     original_created_from = params[:original_created_from].presence
@@ -38,8 +36,8 @@ class PostsController < ApplicationController
     offset = (page - 1) * limit
 
     pt_max_sql =
-        PostVersion
+        PostTag
-        .select('post_id, MAX(created_at) AS max_updated_at')
+        .select('post_id, MAX(updated_at) AS max_updated_at')
         .group('post_id')
         .to_sql
 
@@ -48,12 +46,13 @@ class PostsController < ApplicationController
         'COALESCE(pt_max.max_updated_at, posts.updated_at))'
 
     q =
-        filtered_posts(locale)
+        filtered_posts
         .joins("LEFT JOIN (#{ pt_max_sql }) pt_max ON pt_max.post_id = posts.id")
         .reselect('posts.*', Arel.sql("#{ updated_at_all_sql } AS updated_at_all"))
-        .preload(:external_tags, :uploaded_user, :parents, :children,
+        .preload(:uploaded_user, :parents, :children,
-                 post_tags: [:sections, { tag: [:deerjikists, :materials,
+                 active_post_tags: [:sections,
-                                                { tag_names: :wiki_page }] }])
+                                    { tag: [:deerjikists, :materials,
+                                            { tag_name: :wiki_page }] }])
         .with_attached_thumbnail
 
     q = q.where('posts.url LIKE ?', "%#{ url }%") if url
@@ -92,8 +91,7 @@ class PostsController < ApplicationController
     q = q.except(:select, :order)
 
     render json: { posts: posts.map { |post|
-      PostRepr.base(post, language_code: locale.language_code)
+      PostRepr.base(post).merge(updated_at: post.updated_at_all).tap do |json|
-              .merge(updated_at: post.updated_at_all).tap do |json|
         json['thumbnail'] =
             if post.thumbnail.attached?
               rails_storage_proxy_url(post.thumbnail, only_path: false)
@@ -105,19 +103,16 @@ class PostsController < ApplicationController
   end
 
   def random
-    locale = resolve_locale!
+    post = filtered_posts.preload(:uploaded_user, :parents, :children,
-
+                                  active_post_tags: [:sections,
-    post =
+                                                     { tag: [:deerjikists, :materials,
-        filtered_posts(locale)
+                                                             { tag_name: :wiki_page }] }])
-        .preload(:uploaded_user, :parents, :children,
-                 post_tags: [:sections, { tag: [:deerjikists, :materials,
-                                                { tag_names: :wiki_page }] }])
                          .with_attached_thumbnail
                          .order('RAND()')
                          .first
     return head :not_found unless post
 
-    render json: PostRepr.base(post, current_user, language_code: locale.language_code)
+    render json: PostRepr.base(post, current_user)
   end
 
   def metadata
@@ -192,13 +187,12 @@ class PostsController < ApplicationController
   end
 
   def show
-    locale = resolve_locale!
-
     post =
         Post
         .includes(:uploaded_user, :parents, :children,
-                  post_tags: [:sections, { tag: [:deerjikists, :materials,
+                  active_post_tags: [:sections,
-                                                 { tag_names: :wiki_page }] }])
+                                     { tag: [:deerjikists, :materials,
+                                             { tag_name: :wiki_page }] }])
         .with_attached_thumbnail
         .find_by(id: params[:id])
     return head :not_found unless post
@@ -212,21 +206,18 @@ class PostsController < ApplicationController
                                  parent_posts:,
                                  child_posts:,
                                  sibling_posts:,
-                                 related:,
+                                 related:)
-                                 language_code: locale.language_code)
+                         .merge(tags: build_tag_tree_for(post))
-                         .merge(tags: build_tag_tree_for(post, locale.language_code))
   end
 
   def create
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
-
     preflight = PostCreatePreflight.new(
         attributes: post_create_attributes,
         thumbnail: params[:thumbnail],
-        host: request.base_url).run(locale)
+        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])
@@ -252,10 +243,10 @@ class PostsController < ApplicationController
                                    :post_tag_specs,
                                    :tag_sections,
                                    :normalised_parent_post_ids).symbolize_keys).merge(
-                               thumbnail: params[:thumbnail])).create!(locale)
+                               thumbnail: params[:thumbnail])).create!
 
     post.reload
-    render json: PostRepr.base(post, language_code: locale.language_code), status: :created
+    render json: PostRepr.base(post), status: :created
   rescue PostCreatePreflight::ValidationFailed => e
     render_validation_error fields: e.fields, base: e.base_errors
   rescue Tag::NicoTagNormalisationError
@@ -281,18 +272,13 @@ class PostsController < ApplicationController
     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
-
-    locale = resolve_locale!
-
     posts = parse_bulk_posts_manifest
     thumbnails = parse_bulk_thumbnails(posts.length)
-
     result = PostBulkCreator.new(
         actor: current_user,
         posts:,
         thumbnails:,
-        host: request.base_url).run(locale)
+        host: request.base_url).run
-
     render json: result
   rescue JSON::ParserError
     render_bad_request 'posts manifest の JSON が不正です．'
@@ -325,7 +311,6 @@ class PostsController < ApplicationController
     base_version_no = parse_base_version_no
     return render_bad_request('base_version_no は必須です．') if !(force) && !(base_version_no)
 
-    locale = Locale.find_by(code: params[:locale].presence) || Locale.nipponese
     title = params[:title].presence
     tag_names = params[:tags].to_s.split
     original_created_from = params[:original_created_from]
@@ -345,10 +330,9 @@ class PostsController < ApplicationController
         base_version = post.post_versions.find_by!(version_no: base_version_no)
 
         base_snapshot = post_snapshot_from_version(base_version)
-        current_snapshot = post_snapshot_from_record(post, locale)
+        current_snapshot = post_snapshot_from_record(post)
       end
-      incoming_snapshot = post_incoming_snapshot(locale:,
+      incoming_snapshot = post_incoming_snapshot(title:,
-                                                 title:,
                                                  original_created_from:,
                                                  original_created_before:,
                                                  tag_names:,
@@ -377,14 +361,14 @@ class PostsController < ApplicationController
             end
           end
 
-      apply_post_snapshot!(locale, post, snapshot_to_apply)
+      apply_post_snapshot!(post, snapshot_to_apply)
     end
 
     return render json: conflict_json, status: :conflict if conflict_json
 
     post.reload
-    json = PostRepr.base(post, current_user, language_code: locale.language_code)
+    json = PostRepr.base(post, current_user)
-    json['tags'] = build_tag_tree_for(post, locale.language_code)
+    json['tags'] = build_tag_tree_for(post)
     render json:, status: :ok
   rescue Tag::NicoTagNormalisationError
     render_validation_error fields: { tags: ['ニコニコ・タグは直接指定できません．'] }
@@ -400,21 +384,65 @@ class PostsController < ApplicationController
     render_post_form_record_invalid e.record
   end
 
+  def changes
+    id = params[:id].presence
+    tag_id = params[:tag].presence
+    page = (params[:page].presence || 1).to_i
+    limit = (params[:limit].presence || 20).to_i
+
+    page = 1 if page < 1
+    limit = 1 if limit < 1
+
+    offset = (page - 1) * limit
+
+    pts = PostTag.with_discarded
+    pts = pts.where(post_id: id) if id.present?
+    pts = pts.where(tag_id:) if tag_id.present?
+    pts = pts.includes(:post, :created_user, :deleted_user,
+                       tag: [:deerjikists, :materials, { tag_name: :wiki_page }])
+
+    events = []
+    pts.each do |pt|
+      tag = TagRepr.base(pt.tag)
+      post = pt.post
+
+      events << Event.new(
+          post:,
+          tag:,
+          user: pt.created_user && { id: pt.created_user.id, name: pt.created_user.name },
+          change_type: 'add',
+          timestamp: pt.created_at)
+
+      if pt.discarded_at
+        events << Event.new(
+            post:,
+            tag:,
+            user: pt.deleted_user && { id: pt.deleted_user.id, name: pt.deleted_user.name },
+            change_type: 'remove',
+            timestamp: pt.discarded_at)
+      end
+    end
+    events.sort_by!(&:timestamp)
+    events.reverse!
+
+    render json: { changes: (events.slice(offset, limit) || []).as_json, count: events.size }
+  end
+
   private
 
-  def filtered_posts locale
+  def filtered_posts
     tag_names = params[:tags].to_s.split
     match_type = params[:match]
     if tag_names.present?
-      filter_posts_by_tags(locale, tag_names, match_type)
+      filter_posts_by_tags(tag_names, match_type)
     else
       Post.all
     end
   end
 
-  def filter_posts_by_tags locale, tag_names, match_type
+  def filter_posts_by_tags tag_names, match_type
     literals = tag_names.map do |raw_name|
-      { name: TagName.canonicalise(locale, raw_name.sub(/\Anot:/i, '')).first,
+      { name: TagName.canonicalise(raw_name.sub(/\Anot:/i, '')).first,
         negative: raw_name.downcase.start_with?('not:') }
     end
 
@@ -422,11 +450,11 @@ class PostsController < ApplicationController
 
     if match_type == 'any'
       literals.reduce(Post.none) do |posts, literal|
-        posts.or(tag_literal_relation(locale, literal[:name], negative: literal[:negative]))
+        posts.or(tag_literal_relation(literal[:name], negative: literal[:negative]))
       end
     else
       literals.reduce(Post.all) do |posts, literal|
-        ids = tagged_post_ids_for(locale, literal[:name])
+        ids = tagged_post_ids_for(literal[:name])
         if literal[:negative]
           posts.where.not(id: ids)
         else
@@ -436,8 +464,8 @@ class PostsController < ApplicationController
     end
   end
 
-  def tag_literal_relation locale, name, negative:
+  def tag_literal_relation name, negative:
-    ids = tagged_post_ids_for(locale, name)
+    ids = tagged_post_ids_for(name)
     if negative
       Post.where.not(id: ids)
     else
@@ -445,20 +473,8 @@ class PostsController < ApplicationController
     end
   end
 
-  def tagged_post_ids_for locale, name
+  def tagged_post_ids_for(name) =
-    posts_by_internal_tags =
+      Post.joins(tags: :tag_name).where(tag_names: { name: }).select(:id)
-        Post
-        .joins(tags: :tag_names)
-        .where(tag_names: { language_code: locale.language_code, name: })
-        .select(:id)
-
-    posts_by_external_tags =
-        Post
-        .joins(:external_tags)
-        .where("CONCAT(external_tags.platform, ':', external_tags.name) = ?", name)
-
-    (posts_by_internal_tags + posts_by_external_tags).uniq(&:id)
-  end
 
   def sync_post_tags! post, desired_tags, sections
     desired_tags.each do |t|
@@ -486,13 +502,13 @@ class PostsController < ApplicationController
       end
     end
 
-    PostTag.where(post_id: post.id, tag_id: to_remove.to_a).find_each do |pt|
+    PostTag.where(post_id: post.id, tag_id: to_remove.to_a).kept.find_each do |pt|
-      pt.destroy!
+      pt.discard_by!(current_user)
     end
   end
 
-  def build_tag_tree_for post, language_code = 'ja'
+  def build_tag_tree_for post
-    post_tags = post.post_tags.reject { |post_tag| post_tag.tag.deprecated? }
+    post_tags = post.active_post_tags.reject { |post_tag| post_tag.tag.deprecated? }
     tags = post_tags.map(&:tag)
     tag_ids = tags.map(&:id)
 
@@ -521,7 +537,7 @@ class PostsController < ApplicationController
       sections = sections_by_tag_id.fetch(tag_id, [])
 
       if path.include?(tag_id)
-        return TagRepr.inline(tag, language_code:).merge(children: [], sections:)
+        return TagRepr.inline(tag).merge(children: [], sections:)
       end
 
       if memo.key?(tag_id)
@@ -533,13 +549,10 @@ class PostsController < ApplicationController
 
       children = child_ids.filter_map { |cid| build_node.(cid, new_path) }
 
-      memo[tag_id] = TagRepr.inline(tag, language_code:).merge(children:, sections:)
+      memo[tag_id] = TagRepr.inline(tag).merge(children:, sections:)
     end
 
-    internal_tags = root_ids.filter_map { |id| build_node.call(id, []) }
+    root_ids.filter_map { |id| build_node.call(id, []) }
-    external_tags =
-        post.external_tags.map { ExternalTagRepr.inline(_1).merge(children: [], sections: []) }
-    internal_tags + external_tags
   end
 
   def sibling_posts_by_parent parent_post_ids
@@ -687,48 +700,45 @@ class PostsController < ApplicationController
 
   def editable_tag_names_from_version version
     version.tags_json
-        .select { _1.key?('tag_id') }
+        .reject { _1.fetch('category') == 'nico' }
         .map { Post.tag_snapshot_literal(_1) }
-        .compact
         .sort
   end
 
-  def post_snapshot_from_record post, locale
+  def post_snapshot_from_record post
     { title: post.title,
       video_ms: post.video_ms,
       original_created_from: snapshot_time(post.original_created_from),
       original_created_before: snapshot_time(post.original_created_before),
-      tag_names: editable_tag_names_from_post(post, locale.language_code),
+      tag_names: editable_tag_names_from_post(post),
       parent_post_ids: post.parent_posts.order(:id).pluck(:id) }
   end
 
-  def editable_tag_names_from_post post, language_code
+  def editable_tag_names_from_post post
     post
         .post_tags
-        .joins(tag: :tag_names)
+        .kept
+        .joins(tag: :tag_name)
+        .merge(Tag.not_nico)
         .merge(Tag.where(deprecated_at: nil))
-        .where(tag_names: { language_code:, primary_flg: true })
+        .includes(:sections, tag: :tag_name)
-        .includes(:sections, tag: :tag_names)
         .order('tag_names.name')
         .map do |post_tag|
-      name = post_tag.tag.name(language_code)
+      name = post_tag.tag.tag_name.name
       sections = post_tag.sections.sort_by(&:begin_ms)
 
       next name if sections.empty?
 
       "#{ name }#{ sections.map { Post.section_literal(_1) }.join }"
-    end.compact.sort
+    end
   end
 
-  def post_incoming_snapshot locale:, title:, original_created_from:, original_created_before:,
+  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,
-    Tag.normalise_tags!(locale, tag_names,
+                                        with_sections: true) =>
-                        with_tagme: false,
+        { tags:, sections: }
-                        with_no_deerjikist: false,
-                        deny_deprecated: true,
-                        with_sections: true) => { tags:, sections: }
 
     tags = Tag.expand_parent_tags(tags).reject(&:deprecated?)
     video_ms = normalise_video_ms(tags, video_ms_param:, duration_param:)
@@ -739,7 +749,7 @@ class PostsController < ApplicationController
       original_created_from: snapshot_time(original_created_from),
       original_created_before: snapshot_time(original_created_before),
       tag_names: tags.uniq(&:id).map { |tag|
-        "#{ tag.name(locale.language_code) }#{ sections[tag.id].to_a.map { section_literal(_1) }.join }"
+        "#{ tag.name }#{ sections[tag.id].to_a.map { section_literal(_1) }.join }"
       }.sort,
       parent_post_ids: parent_post_ids.sort }
   end
@@ -863,7 +873,7 @@ class PostsController < ApplicationController
     (added_by_current & removed_by_me).present? || (removed_by_current & added_by_me).present?
   end
 
-  def apply_post_snapshot! locale, post, snapshot
+  def apply_post_snapshot! post, snapshot
     PostVersionRecorder.ensure_snapshot!(post, created_by_user: current_user)
 
     post.update!(title: snapshot[:title],
@@ -871,13 +881,15 @@ class PostsController < ApplicationController
                  original_created_from: snapshot[:original_created_from],
                  original_created_before: snapshot[:original_created_before])
 
-    Tag.normalise_tags!(locale, snapshot[:tag_names],
+    Tag.normalise_tags!(snapshot[:tag_names], with_tagme: false,
-                        with_tagme: false,
                                                deny_deprecated: true,
-                        with_sections: true) => { tags:, sections: }
+                                               with_sections: true) =>
-    TagVersioning.record_tag_snapshots!(tags, created_by_user: current_user,
+        { tags: editable_tags, sections: }
-                                        language_code: locale.language_code)
+    TagVersioning.record_tag_snapshots!(editable_tags, created_by_user: current_user)
 
+    readonly_tags = post.tags.nico.to_a
+
+    tags = readonly_tags + editable_tags
     tags = Tag.expand_parent_tags(tags).reject(&:deprecated?)
 
     post.video_ms = tags.any? { _1.id == Tag.video.id } ? snapshot[:video_ms] : nil

backend/app/controllers/tag_children_controller.rb

@@ -10,6 +10,7 @@ class TagChildrenController < ApplicationController
 
     parent = Tag.find(parent_id)
     child = Tag.find(child_id)
+    return render_bad_request('ニコニコ・タグの階層は変更できません．') if parent.nico? || child.nico?
 
     ApplicationRecord.transaction do
       TagVersioning.ensure_snapshot!(child, created_by_user: current_user)
@@ -32,6 +33,7 @@ class TagChildrenController < ApplicationController
 
     parent = Tag.find(parent_id)
     child = Tag.find(child_id)
+    return render_bad_request('ニコニコ・タグの階層は変更できません．') if parent.nico? || child.nico?
 
     ApplicationRecord.transaction do
       TagVersioning.ensure_snapshot!(child, created_by_user: current_user)

backend/app/controllers/tag_descriptions_controller.rb

@@ -1,57 +0,0 @@
-class TagDescriptionsController < ApplicationController
-  def show
-    description = TagDescription.find_by(tag_id: params[:id], language_code: 'ja')
-    return head :not_found unless description
-
-    render json: representation(description)
-  end
-
-  def show_by_title
-    tag_name = TagName.find_by(language_code: 'ja', name: params[:name].to_s.strip)
-    description = tag_name&.tag && TagDescription.find_by(tag: tag_name.tag, language_code: 'ja')
-    return head :not_found unless description
-
-    render json: representation(description)
-  end
-
-  def update
-    return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
-
-    body = params[:body].to_s
-    return render_unprocessable_entity('本文は必須です．', field: :body) if body.blank?
-
-    tag = Tag.find_by(id: params[:id])
-    return head :not_found unless tag
-
-    description = TagDescription.find_by(tag:, language_code: 'ja')
-
-    if description
-      TagDescriptionOperation.update!(tag:, body:, updated_by_user: current_user)
-      description.reload
-      render json: representation(description)
-    else
-      TagDescriptionOperation.create!(tag:, body:, created_by_user: current_user)
-      description = TagDescription.find_by!(tag:, language_code: 'ja')
-      render json: representation(description), status: :created
-    end
-  rescue ActiveRecord::RecordInvalid => e
-    render_validation_error e.record
-  rescue ActiveRecord::RecordNotUnique
-    render_record_not_unique
-  end
-
-  private
-
-  def representation description
-    description.as_json(only: [
-        :tag_id,
-        :language_code,
-        :body,
-        :version_no,
-        :created_by_user_id,
-        :updated_by_user_id,
-        :created_at,
-        :updated_at])
-  end
-end

backend/app/controllers/tag_groups_controller.rb

@@ -1,39 +0,0 @@
-class TagGroupsController < ApplicationController
-  def index
-    groups = TagGroup.includes(:created_by_user, :updated_by_user).order(:id)
-    render json: TagGroupRepr.many(groups.to_a)
-  end
-
-  def show
-    group = TagGroup.includes(:created_by_user, :updated_by_user).find_by(id: params[:id])
-    return head :not_found unless group
-
-    render json: TagGroupRepr.one(group)
-  end
-
-  def create
-    return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
-
-    group = TagGroupOperation.create!(**write_attributes, actor: current_user)
-    render json: TagGroupRepr.one(group), status: :created
-  end
-
-  def update
-    return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
-
-    group = TagGroup.find_by(id: params[:id])
-    return head :not_found unless group
-
-    TagGroupOperation.update!(group:, **write_attributes, actor: current_user)
-    render json: TagGroupRepr.one(group.reload)
-  end
-
-  private
-
-  def write_attributes
-    { name: params[:name], description: params[:description],
-      members: params[:members], placements: params[:placements] }
-  end
-end

backend/app/controllers/tag_versions_controller.rb

@@ -1,6 +1,5 @@
 class TagVersionsController < ApplicationController
   def index
-    locale = resolve_locale!
     tag_id = params[:id].presence
     page = (params[:page].presence || 1).to_i
     limit = (params[:limit].presence || 20).to_i
@@ -19,8 +18,7 @@ class TagVersionsController < ApplicationController
         SQL
       .select('tag_versions.*', 'prev.name AS prev_name', 'prev.category AS prev_category',
               'prev.deprecated_at AS prev_deprecated_at',
-              'prev.aliases AS prev_aliases', 'prev.names AS prev_names',
+              'prev.aliases AS prev_aliases', 'prev.parent_tag_ids AS prev_parent_tag_ids')
-              'prev.parent_tag_ids AS prev_parent_tag_ids')
     q = q.where('tag_versions.tag_id = ?', tag_id) if tag_id
 
     count = q.except(:select, :order, :limit, :offset).count
@@ -29,20 +27,18 @@ class TagVersionsController < ApplicationController
                 .limit(limit)
                 .offset(offset)
 
-    render json: { versions: serialise_versions(versions, locale.language_code), count: }
+    render json: { versions: serialise_versions(versions), count: }
   end
 
   private
 
-  def serialise_versions rows, language_code
+  def serialise_versions rows
     user_ids = rows.map(&:created_by_user_id).compact.uniq
     users_by_id = User.where(id: user_ids).pluck(:id, :name).to_h
 
     rows.map do |row|
-      current_names = names_for_locale(row.names, language_code)
+      cur_aliases = split_values(row.aliases)
-      previous_names = names_for_locale(row.attributes['prev_names'], language_code)
+      prev_aliases = split_values(row.attributes['prev_aliases'])
-      cur_aliases = current_names.fetch('aliases', []).map { _1.fetch('name') }
-      prev_aliases = previous_names.fetch('aliases', []).map { _1.fetch('name') }
 
       cur_parent_tag_ids = split_parent_tag_ids(row.parent_tag_ids)
       prev_parent_tag_ids = split_parent_tag_ids(row.attributes['prev_parent_tag_ids'])
@@ -51,22 +47,21 @@ class TagVersionsController < ApplicationController
 
       tags_by_id =
           Tag
-          .includes(:tag_names, :materials, tag_names: :wiki_page)
+          .includes(:tag_name, :materials, { tag_name: :wiki_page })
           .where(id: all_parent_tag_ids)
           .index_by(&:id)
 
       parent_tags =
           build_version_values(cur_parent_tag_ids, prev_parent_tag_ids, key: :tag_id)
           .map do |h|
-            { tag: TagRepr.base(tags_by_id[h[:tag_id]], language_code:),
+            { tag: TagRepr.base(tags_by_id[h[:tag_id]]),
               type: h[:type] }
           end
 
       { tag_id: row.tag_id,
         version_no: row.version_no,
         event_type: row.event_type,
-        names: row.names,
+        name: { current: row.name, prev: row.attributes['prev_name'] },
-        name: { current: current_names['name'], prev: previous_names['name'] },
         category: { current: row.category, prev: row.attributes['prev_category'] },
         deprecated_at: { current: row.deprecated_at&.iso8601,
                          prev: row.attributes['prev_deprecated_at']&.iso8601 },
@@ -96,12 +91,5 @@ class TagVersionsController < ApplicationController
 
   def split_values(values) = values.to_s.split(/\s+/).reject(&:blank?)
 
-  def names_for_locale names, language_code
-    values = names.is_a?(String) ? JSON.parse(names) : names
-    values&.fetch(language_code, {}) || {}
-  rescue JSON::ParserError
-    {}
-  end
-
   def split_parent_tag_ids(values) = split_values(values).map(&:to_i)
 end

backend/app/controllers/tags_controller.rb

@@ -5,8 +5,6 @@ require 'set'
 
 class TagsController < ApplicationController
   def index
-    locale = resolve_locale!
-
     post_id = params[:post]
 
     name = params[:name].presence
@@ -36,161 +34,49 @@ class TagsController < ApplicationController
 
     offset = (page - 1) * limit
 
-    tags =
+    q =
         if post_id.present?
-          Tag
+          Tag.joins(:posts, :tag_name)
-              .joins(:posts, :tag_names)
-              .where(tag_names: { language_code: locale.language_code, primary_flg: true },
-                     posts: { id: post_id })
         else
-          Tag
+          Tag.joins(:tag_name)
-              .joins(:tag_names)
-              .where(tag_names: { language_code: locale.language_code, primary_flg: true })
-        end
-
-    external_tags =
-        if post_id.present?
-          ExternalTag.joins(:posts).where(posts: { id: post_id })
-        else
-          ExternalTag.all
-        end
-
-    if name
-      tags = tags.where('tag_names.name LIKE ?', "%#{ name }%")
-      external_tags =
-          external_tags.where("CONCAT(external_tags.platform, ':', external_tags.name) LIKE ?",
-                              "%#{ name }%")
-    end
-
-    if category == 'nico'
-      tags = tags.none
-    elsif category
-      tags = tags.where(category:)
-      external_tags = external_tags.none
-    end
-
-    if post_count_between[0]
-      tags = tags.where('tags.post_count >= ?', post_count_between[0])
-      external_tags = external_tags.where('external_tags.post_count >= ?', post_count_between[0])
-    end
-
-    if post_count_between[1]
-      tags = tags.where('tags.post_count <= ?', post_count_between[1])
-      external_tags = external_tags.where('external_tags.post_count <= ?', post_count_between[1])
-    end
-
-    if created_between[0]
-      tags = tags.where('tags.created_at >= ?', created_between[0])
-      external_tags = external_tags.where('external_tags.created_at >= ?', created_between[0])
-    end
-
-    if created_between[1]
-      tags = tags.where('tags.created_at <= ?', created_between[1])
-      external_tags = external_tags.where('external_tags.created_at <= ?', created_between[1])
-    end
-
-    if updated_between[0]
-      tags = tags.where('tags.updated_at >= ?', updated_between[0])
-      external_tags = external_tags.where('external_tags.created_at >= ?', updated_between[0])
-    end
-
-    if updated_between[1]
-      tags = tags.where('tags.updated_at <= ?', updated_between[1])
-      external_tags = external_tags.where('external_tags.created_at <= ?', updated_between[1])
         end
+        .includes(:tag_name, :materials, tag_name: :wiki_page)
+    q = q.where(posts: { id: post_id }) if post_id.present?
 
+    q = q.where('tag_names.name LIKE ?', "%#{ name }%") if name
+    q = q.where(category:) if category
+    q = q.where('tags.post_count >= ?', post_count_between[0]) if post_count_between[0]
+    q = q.where('tags.post_count <= ?', post_count_between[1]) if post_count_between[1]
+    q = q.where('tags.created_at >= ?', created_between[0]) if created_between[0]
+    q = q.where('tags.created_at <= ?', created_between[1]) if created_between[1]
+    q = q.where('tags.updated_at >= ?', updated_between[0]) if updated_between[0]
+    q = q.where('tags.updated_at <= ?', updated_between[1]) if updated_between[1]
     if deprecated_given
-      if deprecated
+      q = deprecated ? q.where.not(deprecated_at: nil) : q.where(deprecated_at: nil)
-        tags = tags.where.not(deprecated_at: nil)
-        external_tags = external_tags.none
-      else
-        tags = tags.where(deprecated_at: nil)
     end
-    end
-
-    tag_sql = tags.select("'tag' AS source",
-                          'tags.id',
-                          'tag_names.name',
-                          'tags.category',
-                          'tags.post_count',
-                          'tags.created_at',
-                          'tags.updated_at',
-                          'tags.deprecated_at').to_sql
-
-    external_tag_sql = external_tags.select(
-        "'external_tag' AS source",
-        'external_tags.id',
-        "CONCAT(external_tags.platform, ':', external_tags.name) AS name",
-        "'nico' AS category",
-        'external_tags.post_count',
-        'external_tags.created_at',
-        'external_tags.created_at AS updated_at',
-        'NULL AS deprecated_at').to_sql
-
-    union_sql = "#{ tag_sql } UNION ALL #{ external_tag_sql }"
 
     sort_sql =
-        if order[0] == 'category'
+        case order[0]
-          'CASE category ' +
+        when 'name'
+          'tag_names.name'
+        when 'category'
+          'CASE tags.category ' +
           "WHEN 'deerjikist' THEN 0 " +
           "WHEN 'meme' THEN 1 " +
           "WHEN 'character' THEN 2 " +
           "WHEN 'general' THEN 3 " +
           "WHEN 'material' THEN 4 " +
           "WHEN 'meta' THEN 5 " +
-          "WHEN 'nico' THEN 6 " +
+          "WHEN 'nico' THEN 6 END"
-          'END'
         else
-          order[0]
+          "tags.#{ order[0] }"
         end
+    tags = q.order(Arel.sql("#{ sort_sql } #{ order[1] }, tags.id #{ order[1] }"))
+            .limit(limit)
+            .offset(offset)
+            .to_a
 
-    connection = ApplicationRecord.connection
+    render json: { tags: TagRepr.many(tags), count: q.size }
-
-    count = connection.select_value(<<~SQL)
-      SELECT
-        COUNT(0)
-      FROM
-        (#{ union_sql }) legacy_tags
-    SQL
-
-    rows = connection.select_all(<<~SQL).to_a
-      SELECT
-        source
-      , id
-      FROM
-        (#{ union_sql }) legacy_tags
-      ORDER BY
-        #{ sort_sql } #{ order[1] }
-      , id #{ order[1] }
-      , source #{ order[1] }
-      LIMIT
-        #{ limit }
-      OFFSET
-        #{ offset }
-    SQL
-
-    tag_ids = rows.filter { _1['source'] == 'tag' }.map { _1['id'] }
-    external_tag_ids = rows.filter { _1['source'] == 'external_tag' }.map { _1['id'] }
-
-    tags_by_id =
-        Tag
-        .joins(:tag_names)
-        .includes(:tag_names, :materials, tag_names: :wiki_page)
-        .where(tag_names: { language_code: locale.language_code, primary_flg: true },
-               id: tag_ids)
-        .index_by(&:id)
-    external_tags_by_id =
-        ExternalTag
-        .where(id: external_tag_ids)
-        .index_by(&:id)
-
-    render json: { tags: rows.map { |row|
-      if row['source'] == 'tag'
-        TagRepr.base(tags_by_id.fetch(row['id']), language_code: locale.language_code)
-      else
-        external_tag_json(external_tags_by_id.fetch(row['id']))
-      end
-    }, count: }
   end
 
   def with_depth
@@ -198,8 +84,7 @@ class TagsController < ApplicationController
     parent_tag_id = nil if parent_tag_id <= 0
     material_filter = material_filter_param(default: 'any')
 
-    locale = resolve_locale!
+    graph = build_with_depth_graph(material_filter)
-    graph = build_with_depth_graph(material_filter, locale.language_code)
 
     tag_ids =
         if parent_tag_id
@@ -214,154 +99,105 @@ class TagsController < ApplicationController
   end
 
   def autocomplete
-    locale = resolve_locale!
-
     q = params[:q].to_s.strip.sub(/\Anot:/i, '')
-    prefix = "#{ ActiveRecord::Base.sanitize_sql_like(q) }%"
 
     with_nico = bool?(:nico, default: true)
     present_only = bool?(:present, default: true)
 
     alias_rows =
         TagName
-        .where(language_code: locale.language_code, primary_flg: false)
+        .where('name LIKE ?', "#{ q }%")
-        .where('name LIKE ?', prefix)
+        .where.not(canonical_id: nil)
-        .pluck(:tag_id, :name)
+        .pluck(:canonical_id, :name)
 
-    matched_alias_by_tag_id = { }
+    matched_alias_by_tag_name_id = { }
-    tag_ids = []
+    canonical_ids = []
-    alias_rows.each do |tag_id, alias_name|
+
-      tag_ids << tag_id
+    alias_rows.each do |canonical_id, alias_name|
-      matched_alias_by_tag_id[tag_id] ||= alias_name
+      canonical_ids << canonical_id
+      matched_alias_by_tag_name_id[canonical_id] ||= alias_name
     end
 
-    base =
+    base = Tag.joins(:tag_name)
-        Tag
+              .includes(:tag_name, :materials, tag_name: :wiki_page)
-        .joins(:tag_names)
+              .where(deprecated_at: nil)
-        .includes(:tag_names, :materials, tag_names: :wiki_page)
-        .where(tag_names: { language_code: locale.language_code, primary_flg: true },
-               deprecated_at: nil)
     base = base.where('tags.post_count > 0') if present_only
 
-    canonical_hit = base.where('tag_names.name LIKE ?', prefix)
+    canonical_hit =
+        base
+        .where(((with_nico ? '(tags.category = ? AND tag_names.name LIKE ?) OR ' : '') +
+                'tag_names.name LIKE ?'),
+               *(with_nico ? ['nico', "nico:#{ q }%"] : []), "#{ q }%")
 
-    internal_tags = canonical_hit.or(base.where(id: tag_ids.uniq))
+    tags =
+        if canonical_ids.present?
+          canonical_hit.or(base.where(tag_name_id: canonical_ids.uniq))
+        else
+          canonical_hit
+        end
 
-    internal_rows =
+    tags = tags.order(Arel.sql('post_count DESC, tag_names.name')).limit(20).to_a
-        internal_tags
+
-        .order(Arel.sql('tags.post_count DESC, tag_names.name'))
+    render json: tags.map { |tag|
-        .limit(20)
+      TagRepr.base(tag).merge(matched_alias: matched_alias_by_tag_name_id[tag.tag_name_id])
-        .map { |tag|
-          TagRepr.base(tag, language_code: locale.language_code)
-                 .merge(matched_alias: matched_alias_by_tag_id[tag.id])
     }
-
-    return render json: internal_rows unless with_nico
-
-    external_base = ExternalTag.all
-    external_base = external_base.where('post_count > 0') if present_only
-
-    external_rows =
-        external_base
-        .where("CONCAT(platform, ':', name) LIKE ? OR name LIKE ?", prefix, prefix)
-        .order(post_count: :desc, name: :asc)
-        .limit(20)
-        .map { external_tag_json(_1) }
-
-    rows =
-    (internal_rows + external_rows)
-        .sort_by { |row| [-row['post_count'], row['name'] || row[:name]] }
-        .first(20)
-
-    render json: rows
   end
 
   def show
-    locale = resolve_locale!
+    tag = Tag.joins(:tag_name)
-
+             .includes(:tag_name, :materials, tag_name: :wiki_page)
-    tag =
+             .find_by(id: params[:id])
-        Tag
+    if tag
-        .joins(:tag_names)
+      render json: TagRepr.base(tag)
-        .includes(:tag_names, :materials, tag_names: :wiki_page)
+    else
-        .find_by(id: params[:id],
-                 tag_names: { language_code: locale.language_code, primary_flg: true })
-    return render json: TagRepr.base(tag, language_code: locale.language_code) if tag
-
-    external_tag = ExternalTag.find_by(id: params[:id])
-    return render json: ExternalTagRepr.base(external_tag) if external_tag
-
       head :not_found
     end
+  end
 
   def show_by_name
     name = params[:name].to_s.strip
     return render_bad_request('name は必須です．') if name.blank?
 
-    locale = resolve_locale!
+    tag = Tag.joins(:tag_name)
-
+             .includes(:tag_name, :materials, tag_name: :wiki_page)
-    tag =
+             .find_by(tag_names: { name: })
-        Tag
+    if tag
-        .joins(:tag_names)
+      render json: TagRepr.base(tag)
-        .includes(:tag_names, :materials, tag_names: :wiki_page)
+    else
-        .find_by(tag_names: { name:, language_code: locale.language_code, primary_flg: true })
+      head :not_found
-    return render json: TagRepr.base(tag, language_code: locale.language_code) if tag
+    end
-
-    platform, external_name = name.split(':', 2)
-    return head :not_found unless external_name
-
-    external_tag = ExternalTag.find_by(platform:, name: external_name)
-    return head :not_found unless external_tag
-
-    render json: ExternalTagRepr.base(external_tag)
   end
 
   def deerjikists
-    locale = resolve_locale!
+    tag = Tag.joins(:tag_name)
-
+             .includes(:tag_name, tag_name: :wiki_page)
-    tag = 
+             .find_by(id: params[:id])
-        Tag.joins(:tag_names)
-        .includes(:tag_names, tag_names: :wiki_page)
-        .find_by(id: params[:id],
-                 tag_names: { language_code: locale.language_code, primary_flg: true })
     return head :not_found unless tag
 
-    render json: { tag: TagRepr.base(tag, language_code: locale.language_code),
+    render json: { tag: TagRepr.base(tag),
-                   deerjikists: DeerjikistRepr.many(
+                   deerjikists: DeerjikistRepr.many(tag.deerjikists) }
-                       tag.deerjikists,
-                       language_code: locale.language_code) }
   end
 
   def deerjikists_by_name
     name = params[:name].to_s.strip
     return render_bad_request('name は必須です．') if name.blank?
 
-    locale = resolve_locale!
+    tag = Tag.joins(:tag_name)
-
+             .includes(:tag_name, tag_name: :wiki_page)
-    tag =
+             .find_by(tag_names: { name: })
-        Tag
-        .joins(:tag_names)
-        .includes(:tag_names, tag_names: :wiki_page)
-        .find_by(tag_names: { name:, language_code: locale.language_code, primary_flg: true })
     return head :not_found unless tag
 
-    render json: { tag: TagRepr.base(tag, language_code: locale.language_code),
+    render json: { tag: TagRepr.base(tag),
-                   deerjikists: DeerjikistRepr.many(
+                   deerjikists: DeerjikistRepr.many(tag.deerjikists) }
-                       tag.deerjikists,
-                       language_code: locale.language_code) }
   end
 
   def update_deerjikists
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
+    tag = Tag.joins(:tag_name)
-
+             .includes(:tag_name, tag_name: :wiki_page)
-    tag =
+             .find_by(id: params[:id])
-        Tag
-        .joins(:tag_names)
-        .includes(:tag_names, tag_names: :wiki_page)
-        .find_by(id: params[:id],
-                 tag_names: { language_code: locale.language_code, primary_flg: true })
     return head :not_found unless tag
 
     rows = normalise_deerjikist_rows(tag)
@@ -380,7 +216,7 @@ class TagsController < ApplicationController
         row_indexes_by_key.key?([deerjikist.platform, deerjikist.code])
       }
 
-      render_deerjikist_conflicts(locale, requested_deerjikists, row_indexes_by_key, tag)
+      render_deerjikist_conflicts(requested_deerjikists, row_indexes_by_key, tag)
       raise ActiveRecord::Rollback if performed?
 
       requested_keys_set = requested_keys.to_set
@@ -401,7 +237,7 @@ class TagsController < ApplicationController
           render_deerjikist_form_record_invalid(deerjikist, row_index) unless deerjikist.save
         rescue ActiveRecord::RecordNotUnique
           conflicts = lock_deerjikists_for_tag_update(tag.id, [[platform, code]])
-          render_deerjikist_conflicts(locale, conflicts, row_indexes_by_key, tag)
+          render_deerjikist_conflicts(conflicts, row_indexes_by_key, tag)
         end
         raise ActiveRecord::Rollback if performed?
       end
@@ -409,28 +245,22 @@ class TagsController < ApplicationController
 
     return if performed?
 
-    render json: DeerjikistRepr.many(tag.reload.deerjikists,
+    render json: DeerjikistRepr.many(tag.reload.deerjikists)
-                                     language_code: locale.language_code)
   end
 
   def materials_by_name
     name = params[:name].to_s.strip
     return render_bad_request('name は必須です．') if name.blank?
-
-    locale = resolve_locale!
-
     material_filter = material_filter_param(default: 'any')
 
-    tag =
+    tag = Tag.joins(:tag_name)
-        Tag
+             .includes(:tag_name, :materials, tag_name: :wiki_page)
-        .joins(:tag_names)
+             .find_by(tag_names: { name: })
-        .includes(:tag_names, :materials, tag_names: :wiki_page)
-        .find_by(tag_names: { name:, language_code: locale.language_code, primary_flg: true })
     return head :not_found unless tag
 
-    graph = build_with_depth_graph(material_filter, locale.language_code)
+    graph = build_with_depth_graph(material_filter)
 
-    render json: build_tag_children(tag, graph:, language_code: locale.language_code)
+    render json: build_tag_children(tag, graph:)
   end
 
   def update_all
@@ -446,37 +276,39 @@ class TagsController < ApplicationController
     return render_unprocessable_entity('カテゴリは必須です．', field: :category) if category.blank?
     return render_unprocessable_entity '廃止状態は必須です．', field: :deprecated unless params.key?(:deprecated)
 
-    locale = resolve_locale!
+    return unless validate_tag_rename(tag, name)
-
-    return unless validate_tag_rename(locale, tag, name)
 
     alias_names = params[:aliases].to_s.split.uniq
     parent_names = params[:parent_tags].to_s.split.uniq
     deprecated = bool?(:deprecated)
 
-    if category == 'nico'
+    if tag.nico? && deprecated
+      return render_unprocessable_entity 'ニコタグは廃止できません．', field: :deprecated
+    end
+
+    if tag.nico? || category == 'nico'
       return render_unprocessable_entity 'ニコタグは変更できません．', field: :category
     end
 
     ApplicationRecord.transaction do
-      TagVersioning.ensure_snapshot!(tag, created_by_user: current_user,
+      TagVersioning.ensure_snapshot!(tag, created_by_user: current_user)
-                                     language_code: locale.language_code)
 
-      old_name = tag.name(locale.language_code)
+      old_name = tag.name
       name_changed = name != old_name
+      wiki_page = tag.tag_name.wiki_page if name_changed
 
       if tag.deprecated? == deprecated
         tag.update!(category:)
       else
         tag.update!(category:, deprecated_at: deprecated ? Time.current : nil)
       end
-      rename_tag_name!(locale, tag, name) if name_changed
+      rename_tag_name!(tag, name) if name_changed
 
-      alias_names << old_name if name_changed && old_name.present?
+      alias_names << old_name if name_changed
       alias_names.delete(name)
 
-      update_aliases!(locale, tag, alias_names)
+      update_aliases!(tag, alias_names)
-      update_parent_tags!(locale, tag, parent_names)
+      update_parent_tags!(tag, parent_names)
 
       tag.reload
 
@@ -484,18 +316,17 @@ class TagsController < ApplicationController
           tag,
           event_type: :update,
           created_by_user: current_user,
-          language_code: locale.language_code)
+          name_changed:,
+          wiki_page:)
     end
 
-    render json: TagRepr.base(tag.reload, language_code: locale.language_code)
+    render json: TagRepr.base(tag.reload)
   end
 
   def update
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    locale = resolve_locale!
-
     name = params[:name].presence
     category = params[:category].presence
     deprecated_given = params.key?(:deprecated)
@@ -503,20 +334,24 @@ class TagsController < ApplicationController
 
     tag = Tag.find(params[:id])
 
-    return unless validate_tag_rename(locale, tag, name)
+    if tag.nico? && deprecated_given && deprecated
+      return render_unprocessable_entity 'ニコタグは廃止できません．', field: :deprecated
+    end
 
-    if category.present? && category == 'nico'
+    return unless validate_tag_rename(tag, name)
+
+    if tag.nico? || (category.present? && category == 'nico')
       return render_unprocessable_entity 'ニコタグは変更できません．', field: :category
     end
 
     ApplicationRecord.transaction do
-      TagVersioning.ensure_snapshot!(tag, created_by_user: current_user,
+      TagVersioning.ensure_snapshot!(tag, created_by_user: current_user)
-                                     language_code: locale.language_code)
 
-      old_name = tag.name(locale.language_code)
+      old_name = tag.name
       name_changed = name.present? && name != old_name
+      wiki_page = tag.tag_name.wiki_page if name_changed
 
-      rename_tag_name!(locale, tag, name) if name_changed
+      rename_tag_name!(tag, name) if name_changed
       tag.update!(category:) if category.present?
       if deprecated_given && tag.deprecated? != deprecated
         tag.update!(deprecated_at: deprecated ? Time.current : nil)
@@ -528,10 +363,11 @@ class TagsController < ApplicationController
           tag,
           event_type: :update,
           created_by_user: current_user,
-          language_code: locale.language_code)
+          name_changed:,
+          wiki_page:)
     end
 
-    render json: TagRepr.base(tag.reload, language_code: locale.language_code)
+    render json: TagRepr.base(tag.reload)
   end
 
   private
@@ -543,7 +379,7 @@ class TagsController < ApplicationController
     value
   end
 
-  def build_with_depth_graph material_filter, language_code
+  def build_with_depth_graph material_filter
     children_by_parent_id = Hash.new { |h, k| h[k] = [] }
     parent_ids_by_child_id = Hash.new { |h, k| h[k] = [] }
 
@@ -558,11 +394,8 @@ class TagsController < ApplicationController
 
     material_tag_ids = Material.unscoped.kept.where.not(tag_id: nil).distinct.pluck(:tag_id).to_set
 
-    tags_by_id =
+    tags_by_id = Tag.joins(:tag_name)
-        Tag
+                    .where(id: tag_ids)
-        .joins(:tag_names)
-        .where(id: tag_ids,
-               tag_names: { language_code:, primary_flg: true })
                     .pluck('tags.id', 'tag_names.name', 'tags.category', 'tags.deprecated_at')
                     .each_with_object({ }) do |(id, name, category, deprecated_at), h|
       h[id] = { name:, category:, deprecated: deprecated_at.present?,
@@ -696,164 +529,145 @@ class TagsController < ApplicationController
       children: [] }
   end
 
-  def build_tag_children tag, graph: nil, language_code: 'ja'
+  def build_tag_children tag, graph: nil
     material = tag.materials.first
     tag_graph = graph && graph[:tags_by_id][tag.id]
     material =
         nil if tag_graph && !with_depth_visible_tag?(tag_graph, graph[:material_filter])
 
-    children = tag.children.sort_by { _1.name(language_code) }
+    children = tag.children.sort_by(&:name)
     if graph
       children = children.filter { |child_tag| visible_subtree?(child_tag.id, graph) }
     end
 
-    TagRepr.base(tag, language_code:).merge(
+    TagRepr.base(tag).merge(
-        children: children.map { build_tag_children(_1, graph:, language_code:) },
+        children: children.map { build_tag_children(_1, graph:) },
         has_material: tag_graph ? tag_graph[:has_material] : material.present?,
-        material: material && MaterialRepr.base(
+        material: material && MaterialRepr.base(material, host: request.base_url))
-            material,
-            host: request.base_url,
-            language_code:))
   end
 
-  def record_tag_version! tag, event_type:, created_by_user:, language_code: 'ja'
+  def record_tag_version! tag, event_type:, created_by_user:, name_changed: false, wiki_page: nil
-    TagVersionRecorder.record!(tag:, event_type:, created_by_user:, language_code:)
+    if tag.nico?
+      NicoTagVersionRecorder.record!(tag:, event_type:, created_by_user:)
+      return
     end
 
-  def validate_tag_rename locale, tag, name
+    TagVersionRecorder.record!(tag:, event_type:, created_by_user:)
-    return true if name.blank? || name == tag.name(locale.language_code)
 
-    system_tag_names = ['タグ希望', 'bot操作', 'ニジラー情報不詳', '動画', 'ニコニコ']
+    return unless name_changed
-    if TagName.exists?(tag_id: tag.id,
+
-                       language_code: 'ja',
+    wiki_page ||= tag.tag_name.wiki_page
-                       primary_flg: true,
+    return unless wiki_page&.wiki_versions&.exists?
-                       name: system_tag_names)
+
+    WikiVersionRecorder.record!(
+        page: wiki_page,
+        event_type: :update,
+        created_by_user:)
+  end
+
+  def validate_tag_rename tag, name
+    return true if name.blank? || name == tag.name
+
+    if tag.in?([Tag.tagme, Tag.bot, Tag.no_deerjikist, Tag.video, Tag.niconico])
       render_unprocessable_entity 'システム・タグの名称は変更できません．', field: :name
       return false
     end
 
-    target_tag_name = TagName.find_by(language_code: locale.language_code, name:)
+    target_tag_name = TagName.with_discarded.find_by(name:)
-    return true unless target_tag_name&.primary_flg
+    return true if target_tag_name.nil?
+    return true if target_tag_name.canonical_id?
 
     render_unprocessable_entity 'その名前は既に使はれてゐます．', field: :name
     false
   end
 
-  def rename_tag_name! locale, tag, name
+  def rename_tag_name! tag, name
-    return if name == tag.name(locale.language_code)
+    return if name == tag.name
 
-    current_tag_name = tag.tag_name(locale.language_code)
+    current_tag_name = tag.tag_name
-    target_tag_name = TagName.find_by(language_code: locale.language_code, name:)
+    target_tag_name = TagName.with_discarded.find_by(name:)
 
-    unless target_tag_name
+    if target_tag_name.nil?
-      if current_tag_name
+      current_tag_name.update!(name:)
-        current_tag_name.update!(name:, auto_generated: false)
-      else
-        current_tag_name = TagName.create!(
-            tag:,
-            language_code: locale.language_code,
-            script_code: locale.script_code,
-            name:,
-            primary_flg: true)
-        tag.association(:tag_names).reset
-      end
       return
     end
 
-    promote_tag_alias!(tag, current_tag_name:, promoted_tag_name: target_tag_name)
+    promote_tag_alias!(
+        tag,
+        current_tag_name:,
+        promoted_tag_name: target_tag_name)
   end
 
   def promote_tag_alias! tag, current_tag_name:, promoted_tag_name:
-    old_owner_tag = promoted_tag_name.tag
+    old_owner_tag = promoted_tag_name.canonical&.tag
 
     if old_owner_tag && old_owner_tag != tag
       TagVersioning.ensure_snapshot!(old_owner_tag, created_by_user: current_user)
     end
 
-    current_tag_name.wiki_page&.update!(tag_name_id: promoted_tag_name.id)
+    promoted_tag_name.undiscard! if promoted_tag_name.discarded?
-    current_tag_name.association(:wiki_page).reset
+    promoted_tag_name.update!(canonical: nil)
 
-    current_tag_name.update!(canonical_id: promoted_tag_name.id,
+    TagName.with_discarded
-                             primary_flg: false, auto_generated: false)
+           .where(canonical_id: current_tag_name.id)
-    promoted_tag_name.update!(tag:, canonical_id: nil, primary_flg: true, auto_generated: false)
-
-    TagName.where(tag:,
-                  language_code: current_tag_name.language_code,
-                  primary_flg: false)
            .where.not(id: promoted_tag_name.id)
            .find_each do |alias_tag_name|
-      alias_tag_name.update!(canonical_id: promoted_tag_name.id, primary_flg: false)
+      alias_tag_name.update!(canonical: promoted_tag_name)
     end
 
-    tag.update!(tag_name_id: promoted_tag_name.id)
+    current_tag_name.wiki_page&.update!(tag_name: promoted_tag_name)
+    tag.update!(tag_name: promoted_tag_name)
     current_tag_name.association(:wiki_page).reset
     current_tag_name.association(:tag).reset
-    current_tag_name.reload.update!(canonical_id: promoted_tag_name.id, primary_flg: false)
+    current_tag_name.reload.update!(canonical: promoted_tag_name)
 
     return unless old_owner_tag && old_owner_tag != tag
 
-    record_tag_version!(old_owner_tag.reload, event_type: :update,
+    record_tag_version!(old_owner_tag.reload, event_type: :update, created_by_user: current_user)
-                        created_by_user: current_user,
-                        language_code: current_tag_name.language_code)
   end
 
-  def update_aliases! locale, tag, alias_names
+  def update_aliases! tag, alias_names
     alias_names = alias_names.uniq
 
     affected_tags = [tag]
 
-    primary_tag_name = TagName.find_by!(tag:,
+    current_aliases = tag.tag_name.aliases.to_a
-                                        language_code: locale.language_code,
-                                        primary_flg: true)
-    current_aliases = tag.tag_names.where(language_code: locale.language_code,
-                                          primary_flg: false).to_a
 
     current_aliases.each do |alias_tag_name|
       next if alias_names.include?(alias_tag_name.name)
 
-      affected_tags << alias_tag_name.tag
+      affected_tags << alias_tag_name.canonical&.tag
     end
 
     alias_names.each do |alias_name|
-      alias_tag_name = TagName.find_by(language_code: locale.language_code, name: alias_name)
+      alias_tag_name = TagName.find_undiscard_or_create_by!(name: alias_name)
-      if alias_tag_name&.primary? && alias_tag_name.tag_id && alias_tag_name.tag_id != tag.id
+      affected_tags << alias_tag_name.canonical&.tag
-        alias_tag_name.errors.add(:name, 'その名前は既に使はれてゐます．')
-        raise ActiveRecord::RecordInvalid, alias_tag_name
-      end
-      affected_tags << alias_tag_name&.tag
     end
 
     affected_tags.compact.uniq.each do |affected_tag|
-      TagVersioning.ensure_snapshot!(affected_tag, created_by_user: current_user,
+      TagVersioning.ensure_snapshot!(affected_tag, created_by_user: current_user)
-                                     language_code: locale.language_code)
     end
 
     current_aliases.each do |alias_tag_name|
       next if alias_names.include?(alias_tag_name.name)
 
-      alias_tag_name.update!(canonical_id: nil, tag_id: nil)
+      alias_tag_name.update!(canonical: nil)
     end
 
     alias_names.each do |alias_name|
-      alias_tag_name = TagName.find_or_initialize_by(
+      alias_tag_name = TagName.find_undiscard_or_create_by!(name: alias_name)
-          language_code: locale.language_code,
+      alias_tag_name.update!(canonical: tag.tag_name)
-          name: alias_name)
-      alias_tag_name.script_code = locale.script_code
-      alias_tag_name.update!(tag:, primary_flg: false, auto_generated: false,
-                             canonical_id: primary_tag_name.id)
     end
 
     affected_tags.compact.uniq.each do |affected_tag|
-      record_tag_version!(affected_tag, event_type: :update,
+      record_tag_version!(affected_tag, event_type: :update, created_by_user: current_user)
-                          created_by_user: current_user,
-                          language_code: locale.language_code)
     end
   end
 
-  def update_parent_tags! locale, tag, parent_names
+  def update_parent_tags! tag, parent_names
-    parent_tags = Tag.normalise_tags!(locale, parent_names,
+    parent_tags = Tag.normalise_tags!(parent_names, with_tagme: false,
-                                      with_tagme: false,
+                                                    with_no_deerjikist: false,
-                                      with_no_deerjikist: false)
+                                                    deny_nico: true)
 
     old_parent_tags = tag.parents.to_a
 
@@ -926,15 +740,13 @@ class TagsController < ApplicationController
       .to_a
   end
 
-  def render_deerjikist_conflicts locale, deerjikists, row_indexes_by_key, tag
+  def render_deerjikist_conflicts deerjikists, row_indexes_by_key, tag
     conflicts = deerjikists.filter { |deerjikist| deerjikist.tag_id != tag.id }
     return if conflicts.empty?
 
-    tag_names_by_id =
+    tag_names_by_id = Tag
-        Tag
+                      .joins(:tag_name)
-        .joins(:tag_names)
+                      .where(id: conflicts.map(&:tag_id).uniq)
-        .where(tag_names: { language_code: locale.language_code, primary_flg: true },
-               id: conflicts.map(&:tag_id).uniq)
                       .pluck('tags.id', 'tag_names.name')
                       .to_h
     fields = { }
@@ -983,20 +795,4 @@ class TagsController < ApplicationController
 
     render_validation_error fields:
   end
-
-  def external_tag_json tag
-    { 'id' => tag.id,
-      'name' => "#{ tag.platform }:#{ tag.name }",
-      'category' => 'nico',
-      'deprecated_at' => nil,
-      'created_at' => tag.created_at,
-      'updated_at' => tag.created_at,
-      'post_count' => tag.post_count,
-      'matched_alias' => nil,
-      'aliases' => [],
-      'parents' => [],
-      'has_wiki' => false,
-      'material_id' => nil,
-      'has_deerjikists' => false }
-  end
 end

backend/app/controllers/theatre_skip_events_controller.rb

@@ -6,7 +6,7 @@ class TheatreSkipEventsController < ApplicationController
     events =
         TheatreSkipEvent
         .where(theatre_id: params[:theatre_id])
-        .includes(:post, tags: :tag_names)
+        .includes(:post, tags: :tag_name)
         .order(created_at: :desc)
         .limit(limit)
 
@@ -14,7 +14,7 @@ class TheatreSkipEventsController < ApplicationController
       { id: event.id,
         theatre_id: event.theatre_id,
         post: { id: event.post.id, title: event.post.title, url: event.post.url },
-        tags: event.tags.map { |tag| { id: tag.id, name: tag.name('ja') } },
+        tags: event.tags.map { |tag| { id: tag.id, name: tag.name } },
         programme_position: event.programme_position,
         created_at: event.created_at }
     }

backend/app/controllers/wiki_pages_controller.rb

@@ -2,88 +2,47 @@ class WikiPagesController < ApplicationController
   rescue_from Wiki::Commit::Conflict, with: :render_wiki_conflict
 
   def index
-    # 互換性のための化石リソース
-
     title = params[:title].to_s.strip
-    descriptions =
+    if title.blank?
-        TagDescription.where(language_code: 'ja')
+      return render json: WikiPageRepr.base(
-        .includes(tag: :tag_names)
+          WikiPage.joins(:tag_name).includes(tag_name: :tag))
-    pages = unmigrated_wiki_pages.includes(tag_name: :tag)
-
-    tag_groups = TagGroup.all
-    if title.present?
-      pattern = "%#{ ApplicationRecord.sanitize_sql_like(title) }%"
-      descriptions =
-          descriptions.joins(tag: :tag_names)
-          .where(tag_names: { language_code: 'ja', primary_flg: true })
-          .where('tag_names.name LIKE ?', pattern).limit(20)
-      tag_groups = tag_groups.where(
-          'CONCAT(?, name) LIKE ?', TagGroupRepr::PREFIX, pattern).limit(20)
-      pages = pages.where('tag_names.name LIKE ?', pattern).limit(20)
     end
 
-    json = descriptions.map { |description| WikiPageRepr.tag_description(description) }
+    q = WikiPage.joins(:tag_name).includes(tag_name: :tag)
-    json.concat(tag_groups.map { WikiPageRepr.tag_group(_1) })
+        .where('tag_names.name LIKE ?', "%#{ WikiPage.sanitize_sql_like(title) }%")
-    json.concat(WikiPageRepr.base(pages))
+    render json: WikiPageRepr.base(q.limit(20))
-    json = json.first(20) if title.present?
-    render json:
   end
 
   def show
-    tag_description = TagDescription.find_by(id: params[:id])
-
-    return render_wiki_page_by_tag_description tag_description if tag_description
-
-    tag_group = TagGroup.find_by(id: params[:id])
-    return render_tag_group tag_group if tag_group
-
     page = WikiPage.joins(:tag_name)
                    .includes(tag_name: :tag)
                    .find_by(id: params[:id])
-
     render_wiki_page_or_404 page
   end
 
   def show_by_title
     title = params[:title].to_s.strip
-
+    page = WikiPage.joins(:tag_name)
-    if title.start_with?(TagGroupRepr::PREFIX)
-      name = title.delete_prefix(TagGroupRepr::PREFIX)
-      tag_group = TagGroup.find_by(name:)
-      return render_tag_group tag_group if tag_group
-      return head :not_found
-    end
-
-    tag_description = tag_description_by_title(title)
-
-    return render_wiki_page_by_tag_description tag_description if tag_description
-
-    page =
-        WikiPage
-        .joins(:tag_name)
                    .includes(tag_name: :tag)
                    .find_by(tag_name: { name: title })
-
     render_wiki_page_or_404 page
   end
 
   def exists
-    return head :no_content if TagDescription.exists?(id: params[:id])
+    if WikiPage.exists?(id: params[:id])
-    return head :no_content if TagGroup.exists?(id: params[:id])
+      head :no_content
-
+    else
-    head WikiPage.exists?(id: params[:id]) ? :no_content : :not_found
+      head :not_found
+    end
   end
 
   def exists_by_title
     title = params[:title].to_s.strip
-    if title.start_with?(TagGroupRepr::PREFIX)
+    if WikiPage.joins(:tag_name).exists?(tag_names: { name: title })
-      exists = TagGroup.exists?(name: title.delete_prefix(TagGroupRepr::PREFIX))
+      head :no_content
-      return head exists ? :no_content : :not_found
+    else
+      head :not_found
     end
-    return head :no_content if tag_description_by_title(title)
-
-    exists = WikiPage.joins(:tag_name).exists?(tag_names: { name: title })
-    head exists ? :no_content : :not_found
   end
 
   def diff
@@ -93,49 +52,35 @@ class WikiPagesController < ApplicationController
     from = params[:from].presence
     to = params[:to].presence
 
-    description = TagDescription.find_by(id:)
-    if description
-      versions = description_versions(description)
-      from_rev = from && versions.find(from)
-      to_rev = to ? versions.find(to) : versions.find_by!(version_no: description.version_no)
-      resource = WikiPageRepr.tag_description(description)
-    else
-      tag_group = TagGroup.find_by(id:)
-      if tag_group
-        from_rev = from && group_version(tag_group, from)
-        to_rev = to ? group_version(tag_group, to) : current_group_version(tag_group)
-        return head :not_found if (from && !from_rev) || !to_rev
-
-        from_body = from_rev && render_group_version(from_rev)
-        to_body = render_group_version(to_rev)
-        resource = { 'id' => tag_group.id,
-                     'title' => "#{ TagGroupRepr::PREFIX }#{ tag_group.name }",
-                     'deprecated_at' => nil }
-      else
     page = WikiPage.joins(:tag_name).includes(tag_name: :tag).find(id)
+
     from_rev = from && page.wiki_revisions.find(from)
     to_rev = to ? page.wiki_revisions.find(to) : page.current_revision
-        if ((from_rev && !from_rev.content?) || !to_rev&.content?)
+    if ((from_rev && !(from_rev.content?)) || !(to_rev&.content?))
       return render_unprocessable_entity('差分を表示できない版です．')
     end
-        from_body = from_rev&.body
-        to_body = to_rev.body
-        resource = WikiPageRepr.base(page)
-      end
-    end
 
-    from_body ||= from_rev&.body
+    diffs = Diff::LCS.sdiff(from_rev&.body&.lines || [], to_rev.body.lines)
-    to_body ||= to_rev.body
+    diff_json = diffs.map { |change|
-    diff_json = wiki_diff(from_body, to_body)
+      case change.action
+      when ?=
+        { type: 'context', content: change.old_element }
+      when ?!
+        [{ type: 'removed', content: change.old_element },
+         { type: 'added', content: change.new_element }]
+      when ?+
+        { type: 'added', content: change.new_element }
+      when ?-
+        { type: 'removed', content: change.old_element }
+      end
+    }.flatten.compact
 
-    render json: { wiki_page_id:      resource.fetch('id'),
+    render json: { wiki_page_id:      page.id,
-                   title:             resource.fetch('title'),
+                   title:             page.title,
-                   deprecated_at:     resource.fetch('deprecated_at'),
+                   deprecated_at:     page.deprecated_at,
                    older_revision_id: from_rev&.id,
                    newer_revision_id: to_rev.id,
                    diff:              diff_json }
-  rescue TagGroupMarkdownRenderer::UnsupportedStructure => error
-    render_unprocessable_entity(error.message)
   end
 
   def create
@@ -149,43 +94,20 @@ class WikiPagesController < ApplicationController
     return render_unprocessable_entity('タイトルは必須です．', field: :title) if title.blank?
     return render_unprocessable_entity('本文は必須です．', field: :body) if body.blank?
 
-    if title.start_with?(TagGroupRepr::PREFIX)
+    tag_name = TagName.find_undiscard_or_create_by!(name: title)
-      name = title.delete_prefix(TagGroupRepr::PREFIX)
-      parsed = TagGroupMarkdownParser.parse(body:, group: nil)
-      group = TagGroupOperation.create!(name:, **parsed, actor: current_user,
-                                         require_compatibility: true)
-      version = current_group_version(group)
-      return render_group_representation(TagGroupRepr.one(group), version,
-                                         body: parsed.fetch(:compatibility_body),
-                                         status: :created)
-    end
 
-    page = if title.include?(':')
+    page =
-      ApplicationRecord.transaction do
+        Wiki::Commit.create_content!(
-        tag_name = TagName.find_or_create_by!(language_code: 'ja', name: title) do |name|
+            tag_name:,
-          name.script_code = 'Jpan'
+            body:,
-          name.primary_flg = true
+            created_by_user: current_user,
-          name.auto_generated = false
+            message:)
-        end
-
-        Wiki::Commit.create_legacy_content!(
-            tag_name:, body:, created_by_user: current_user, message:)
-      end
-    else
-      tag_name = TagName.find_by(language_code: 'ja', name: title)
-      return render_unprocessable_entity field: :title unless tag_name&.tag
-
-      TagDescriptionOperation.create!(
-          tag: tag_name.tag, body:, created_by_user: current_user, message:)
-    end
 
     render json: WikiPageRepr.base(page), status: :created
   rescue ActiveRecord::RecordInvalid => e
     render_validation_error e.record
   rescue ActiveRecord::RecordNotUnique
     render_record_not_unique
-  rescue TagGroupMarkdownParser::InvalidDocument => error
-    render_unprocessable_entity(error.message)
   end
 
   def update
@@ -198,26 +120,7 @@ class WikiPagesController < ApplicationController
     return render_unprocessable_entity('タイトルは必須です．', field: :title) if title.blank?
     return render_unprocessable_entity('本文は必須です．', field: :body) if body.blank?
 
-    group = TagGroup.find_by(id: params[:id])
+    page = WikiPage.find(params[:id])
-    if title.start_with?(TagGroupRepr::PREFIX)
-      return head :not_found unless group
-
-      name = title.delete_prefix(TagGroupRepr::PREFIX)
-      parsed = TagGroupMarkdownParser.parse(body:, group:)
-      TagGroupOperation.update!(group:, name:, **parsed, actor: current_user,
-                                require_compatibility: true)
-      return head :ok
-    end
-
-    page = WikiPage.find_by(id: params[:id])
-    if legacy_group_page?(page)
-      return render_unprocessable_entity field: :title
-    end
-    if group && !legacy_update_identified?(page, title, group)
-      return render_unprocessable_entity field: :title
-    end
-    return head :not_found unless page
-
     base_revision_id = params[:base_revision_id].presence
 
     ApplicationRecord.transaction do
@@ -225,7 +128,7 @@ class WikiPagesController < ApplicationController
 
       old_title = page.title
 
-      tag = page.tag_name.tag
+      tag = Tag.find_by(tag_name_id: page.tag_name_id)
 
       if tag && title != old_title
         TagVersioning.ensure_snapshot!(tag, created_by_user: current_user)
@@ -234,17 +137,11 @@ class WikiPagesController < ApplicationController
       page.tag_name.update!(name: title) if title != old_title
 
       message = params[:message].presence
-      description = TagDescription.find_by(id: page.id)
+      Wiki::Commit.content!(page:,
-      description_page = description && (
+                            body:,
-          tag&.id == description.tag_id ||
+                            created_user: current_user,
-          (tag.nil? && !old_title.include?(':')))
+                            message:,
-      if description && !description_page
+                            base_revision_id:)
-        Wiki::Commit.legacy_content!(page:, body:, created_user: current_user,
-                                     message:, base_revision_id:)
-      else
-        Wiki::Commit.content!(page:, body:, created_user: current_user,
-                              message:, base_revision_id:)
-      end
 
       if tag && title != old_title
         tag.reload
@@ -253,32 +150,20 @@ class WikiPagesController < ApplicationController
     end
 
     head :ok
-  rescue ActiveRecord::RecordInvalid => e
+  end
-    render_validation_error e.record
+
-  rescue ActiveRecord::RecordNotUnique
+  def search
-    render_record_not_unique
+    index
-  rescue TagGroupMarkdownParser::InvalidDocument => error
-    render_unprocessable_entity(error.message)
   end
 
   def changes
     id = params[:id].presence
-    description = id && TagDescription.find_by(id:)
+    q = WikiRevision.joins(wiki_page: :tag_name)
-    if description
-      return render json: description_changes(TagDescription.where(id: description.id))
-    end
-
-    tag_group = id && TagGroup.find_by(id:)
-    if tag_group
-      return render json: tag_group_changes(TagGroupVersion.where(tag_group_id: tag_group.id))
-    end
-
-    pages = id ? WikiPage.where(id:) : unmigrated_wiki_pages
-    revisions = WikiRevision.joins(wiki_page: :tag_name)
-        .where(wiki_page_id: pages.select(:id))
                     .includes(:created_user, wiki_page: { tag_name: :tag })
-        .order(id: :desc).limit(200)
+                    .order(id: :desc)
-    json = revisions.map { |rev|
+    q = q.where(wiki_page_id: id) if id
+
+    render json: q.limit(200).map { |rev|
       { revision_id:  rev.id,
         pred:         rev.base_revision_id,
         succ:         nil,
@@ -289,124 +174,11 @@ class WikiPagesController < ApplicationController
         kind:         rev.kind,
         message:      rev.message,
         timestamp:    rev.created_at }
-    }
+    }.compact
-    unless id
-      json.concat(tag_group_changes(TagGroupVersion.all))
-      json.concat(description_changes(TagDescription.where(language_code: 'ja')))
-      json = json.each_with_index.sort_by do |row, index|
-        [-row.fetch(:timestamp).to_f, index]
-      end.map(&:first)
-    end
-    render json: json.first(200)
   end
 
   private
 
-  def legacy_group_page? page
-    return false unless page
-    return true if page.title.start_with?(TagGroupRepr::PREFIX)
-
-    prefix = ApplicationRecord.sanitize_sql_like(TagGroupRepr::PREFIX)
-    page.wiki_versions.where('title LIKE ?', "#{ prefix }%").exists?
-  end
-
-  def legacy_update_identified? page, title, group
-    return false unless page
-    return true if page.title == title
-    return false if title == group.name
-
-    namespace = page.title.split(':', 2)
-    return true if namespace.size == 2 && title.start_with?("#{ namespace.first }:")
-
-    base = params[:base_revision_id].presence
-    base && page.wiki_revisions.exists?(id: base)
-  end
-
-  def render_tag_group group
-    version = if params[:version].present?
-      group_version(group, params[:version])
-    else
-      current_group_version(group)
-    end
-    return head :not_found unless version
-
-    representation = if params[:version].present?
-      TagGroupRepr.historical(version)
-    else
-      TagGroupRepr.one(group)
-    end
-    render_group_representation(representation, version)
-  end
-
-  def render_group_version version
-    representation = TagGroupRepr.historical(version)
-    TagGroupMarkdownRenderer.render(representation)
-  end
-
-  def render_group_representation representation, version, body: nil, status: :ok
-    body ||= TagGroupMarkdownRenderer.render(representation)
-    versions = TagGroupVersion.where(tag_group_id: version.tag_group_id)
-    pred = versions.find_by(version_no: version.version_no - 1)&.id
-    succ = versions.find_by(version_no: version.version_no + 1)&.id
-    updated_at = version.created_at
-    render json: {
-        'id' => version.tag_group_id,
-        'title' => "#{ TagGroupRepr::PREFIX }#{ representation.fetch('name') }",
-        'deprecated_at' => nil,
-        'body' => body,
-        'revision_id' => version.id,
-        'pred' => pred,
-        'succ' => succ,
-        'updated_at' => updated_at }, status:
-  rescue TagGroupMarkdownRenderer::UnsupportedStructure => error
-    render_unprocessable_entity(error.message)
-  end
-
-  def current_group_version group
-    TagGroupVersion.find_by(tag_group_id: group.id, version_no: group.version_no)
-  end
-
-  def group_version group, version_id
-    TagGroupVersion.find_by(tag_group_id: group.id, id: version_id)
-  end
-
-  def wiki_diff from_body, to_body
-    diffs = Diff::LCS.sdiff(from_body.to_s.lines, to_body.to_s.lines)
-    diffs.map { |change|
-      case change.action
-      when ?=
-        { type: 'context', content: change.old_element }
-      when ?!
-        [{ type: 'removed', content: change.old_element },
-         { type: 'added', content: change.new_element }]
-      when ?+
-        { type: 'added', content: change.new_element }
-      when ?-
-        { type: 'removed', content: change.old_element }
-      end
-    }.flatten.compact
-  end
-
-  def tag_group_changes versions
-    rows = versions.includes(:created_by_user).order(id: :desc).limit(200).to_a
-    groups = TagGroup.where(id: rows.map(&:tag_group_id).uniq).index_by(&:id)
-    predecessors = TagGroupVersion.where(tag_group_id: groups.keys,
-                                         version_no: rows.map { _1.version_no - 1 })
-        .pluck(:tag_group_id, :version_no, :id)
-        .to_h { |group_id, number, version_id| [[group_id, number], version_id] }
-    rows.map do |version|
-      group = groups.fetch(version.tag_group_id)
-      user = version.created_by_user
-      { revision_id: version.id,
-        pred: predecessors[[group.id, version.version_no - 1]],
-        succ: nil,
-        wiki_page: { id: group.id, title: "#{ TagGroupRepr::PREFIX }#{ version.name }",
-                     deprecated_at: nil },
-        user: user && { id: user.id, name: user.name },
-        kind: 'content', message: nil, timestamp: version.created_at }
-    end
-  end
-
   def render_wiki_page_or_404 page
     return head :not_found unless page
 
@@ -428,70 +200,6 @@ class WikiPagesController < ApplicationController
     render json: WikiPageRepr.base(page).merge(body:, revision_id:, pred:, succ:, updated_at:)
   end
 
-  def render_wiki_page_by_tag_description description
-    versions = description_versions(description)
-    historical = params[:version].present?
-    rev = historical ? versions.find_by(id: params[:version]) :
-        versions.find_by(version_no: description.version_no)
-    return head :not_found unless rev
-
-    pred = versions.find_by(version_no: rev.version_no - 1)&.id
-    succ = versions.find_by(version_no: rev.version_no + 1)&.id
-    body = historical ? rev.body : description.body
-    updated_at = historical ? rev.created_at : description.updated_at
-    render json: WikiPageRepr.tag_description(description).merge(
-        body:, revision_id: rev.id, pred:, succ:, updated_at:)
-  end
-
-  def description_versions description
-    TagDescriptionVersion.where(tag_id: description.tag_id,
-                                language_code: description.language_code)
-  end
-
-  def tag_description_by_title title
-    TagDescription.joins(tag: :tag_names)
-        .find_by(language_code: 'ja', tag_names: { language_code: 'ja', name: title })
-  end
-
-  def unmigrated_wiki_pages
-    descriptions = TagDescription.where(language_code: 'ja')
-
-    WikiPage
-        .joins(:tag_name)
-        .where.not('tag_names.name LIKE ?', "#{ TagGroupRepr::PREFIX }%")
-        .where('tag_names.tag_id IS NULL OR tag_names.tag_id NOT IN (?)',
-               descriptions.select(:tag_id))
-  end
-
-  def description_changes descriptions
-    versions = TagDescriptionVersion.where(language_code: 'ja',
-                                           tag_id: descriptions.select(:tag_id))
-        .order(id: :desc).limit(200).to_a
-    return [] if versions.empty?
-
-    by_tag = descriptions.where(tag_id: versions.map(&:tag_id))
-        .includes(tag: :tag_names).index_by(&:tag_id)
-    users = User.where(id: versions.map(&:created_by_user_id)).index_by(&:id)
-    predecessors = TagDescriptionVersion.where(
-        language_code: 'ja', tag_id: by_tag.keys,
-        version_no: versions.map { |version| version.version_no - 1 })
-        .pluck(:tag_id, :version_no, :id)
-        .to_h { |tag_id, version_no, id| [[tag_id, version_no], id] }
-    versions.map do |version|
-      description = by_tag.fetch(version.tag_id)
-      user = users[version.created_by_user_id]
-      { revision_id: version.id,
-        pred: predecessors[[version.tag_id, version.version_no - 1]],
-        succ: nil,
-        wiki_page: { id: description.id, title: description.tag.name('ja'),
-                     deprecated_at: description.tag.deprecated_at },
-        user: user && { id: user.id, name: user.name },
-        kind: 'content',
-        message: nil,
-        timestamp: version.created_at }
-    end
-  end
-
   def find_revision page
     if params[:version].present?
       page.wiki_revisions.find_by(id: params[:version])

backend/app/models/external_tag.rb

@@ -1,24 +0,0 @@
-class ExternalTag < ApplicationRecord
-  enum :platform, nico: 'nico'
-  validates :platform, presence: true, inclusion: { in: ExternalTag.platforms.keys }
-
-  has_many :post_external_tags, dependent: :delete_all
-  has_many :posts, through: :post_external_tags
-
-  has_many :nico_tag_versions, foreign_key: :tag_id, inverse_of: :external_tag
-
-  has_many :nico_tag_relations,
-           foreign_key: :nico_tag_id,
-           inverse_of: :nico_tag,
-           dependent: :destroy
-
-  has_many :linked_tags, through: :nico_tag_relations, source: :tag
-
-  def snapshot_linked_tag_names language_code = 'ja'
-    linked_tags
-        .joins(:tag_names)
-        .where(tag_names: { language_code:, primary_flg: true })
-        .order('tag_names.name')
-        .pluck('tag_names.name')
-  end
-end

backend/app/models/language.rb

@@ -1,5 +0,0 @@
-class Language < ApplicationRecord
-  has_many :locales, foreign_key: :language_code, primary_key: :code
-
-  enum :code, ja: 'ja'
-end

backend/app/models/locale.rb

@@ -1,27 +0,0 @@
-class Locale < ApplicationRecord
-  after_create_commit :generate_tag_names!
-
-  belongs_to :language, foreign_key: :language_code, primary_key: :code
-  belongs_to :script, foreign_key: :script_code, primary_key: :code
-
-  enum :code, ja: 'ja', en: 'en', fr: 'fr'
-
-  def self.nipponese = Locale.find('ja')
-
-  private
-
-  def generate_tag_names!
-    ApplicationRecord.transaction do
-      tag_ids = TagName.where(language_code:, primary_flg: true).pluck(:tag_id)
-      Tag.where.not(id: tag_ids).find_each do
-        TagName.create!(tag_id: _1.id,
-                        language_code:,
-                        name: TagName.generate_name(self, _1, _1.tag_name('ja')),
-                        script_code:,
-                        primary_flg: true,
-                        auto_generated: true,
-                        canonical_id: nil)
-      end
-    end
-  end
-end

backend/app/models/nico_tag_relation.rb

@@ -1,10 +1,24 @@
 class NicoTagRelation < ApplicationRecord
-  belongs_to :nico_tag,
+  belongs_to :nico_tag, class_name: 'Tag'
-             class_name: 'ExternalTag',
+  belongs_to :tag, class_name: 'Tag'
-             foreign_key: :nico_tag_id,
-             inverse_of: :nico_tag_relations
-  belongs_to :tag, class_name: 'Tag', foreign_key: :tag_id
 
   validates :nico_tag_id, presence: true
   validates :tag_id, presence: true
+
+  validate :nico_tag_must_be_nico
+  validate :tag_mustnt_be_nico
+
+  private
+
+  def nico_tag_must_be_nico
+    if nico_tag && nico_tag.category != 'nico'
+      errors.add :nico_tag_id, 'タグのカテゴリがニコニコである必要があります．'
+    end
+  end
+
+  def tag_mustnt_be_nico
+    if tag && tag.category == 'nico'
+      errors.add :tag_id, '連携先タグのカテゴリはニコニコであってはなりません．'
+    end
+  end
 end

backend/app/models/nico_tag_version.rb

@@ -1,7 +1,7 @@
 class NicoTagVersion < ApplicationRecord
   include VersionRecord
 
-  belongs_to :external_tag, foreign_key: :tag_id, inverse_of: :nico_tag_versions
+  belongs_to :tag
 
   validates :name, presence: true
 end

backend/app/models/post.rb

@@ -55,27 +55,25 @@ class Post < ApplicationRecord
   belongs_to :uploaded_user, class_name: 'User', optional: true
 
   has_many :post_tags, dependent: :destroy, inverse_of: :post
-  has_many :tags, through: :post_tags
+  has_many :active_post_tags, -> { kept }, class_name: 'PostTag', inverse_of: :post
+  has_many :post_tags_with_discarded, -> { with_discarded }, class_name: 'PostTag'
+  has_many :tags, through: :active_post_tags
   has_many :active_tags, -> { where(tags: { deprecated_at: nil }) },
-           through: :post_tags,
+           through: :active_post_tags, source: :tag
-           source: :tag
 
   has_many :user_post_views, dependent: :delete_all
   has_many :post_similarities, dependent: :delete_all
   has_many :post_versions
-
   has_many :gekanator_guessed_games,
            class_name: 'GekanatorGame',
            foreign_key: :guessed_post_id,
            dependent: :delete_all,
            inverse_of: :guessed_post
-
   has_many :gekanator_correct_games,
            class_name: 'GekanatorGame',
            foreign_key: :correct_post_id,
            dependent: :delete_all,
            inverse_of: :correct_post
-
   has_many :gekanator_question_examples, dependent: :delete_all
 
   has_many :parent_post_implications,
@@ -92,9 +90,6 @@ class Post < ApplicationRecord
            inverse_of: :parent_post
   has_many :children, through: :child_post_implications, source: :post
 
-  has_many :post_external_tags, dependent: :destroy
-  has_many :external_tags, through: :post_external_tags
-
   has_one_attached :thumbnail
 
   attribute :version_no, :integer, default: 1
@@ -126,14 +121,14 @@ class Post < ApplicationRecord
     super(options).merge(thumbnail: nil)
   end
 
-  def snapshot_tag_names language_code = 'ja'
+  def snapshot_tag_names
     post_tags
-        .joins(tag: :tag_names)
+        .kept
-        .where(tag_names: { language_code:, primary_flg: true })
+        .joins(tag: :tag_name)
-        .includes(:sections, tag: :tag_names)
+        .includes(:sections, tag: :tag_name)
         .order('tag_names.name')
         .map do |post_tag|
-      name = post_tag.tag.name(language_code)
+      name = post_tag.tag.tag_name.name
       sections = post_tag.sections.sort_by(&:begin_ms)
 
       next name if sections.empty?
@@ -153,29 +148,21 @@ class Post < ApplicationRecord
     "#{ tag.fetch('name') }#{ sections.join }"
   end
 
-  def snapshot_tags_json language_code = 'ja'
+  def snapshot_tags_json
-    tag_snapshots =
     post_tags
-            .joins(tag: :tag_names)
+        .kept
-            .where(tag_names: { language_code:, primary_flg: true })
+        .joins(tag: :tag_name)
-            .includes(:sections, tag: :tag_names)
+        .includes(:sections, tag: :tag_name)
         .order('tags.id')
-            .map { |pt|
+        .map do |pt|
-          { 'tag_id' => pt.tag.id,
+      { 'id' => pt.tag.id,
         'version_no' => pt.tag.version_no,
-            'name' => pt.tag.name(language_code),
+        'name' => pt.tag.name,
         'category' => pt.tag.category,
         'sections' => pt.sections.sort_by(&:begin_ms).map {
           { 'begin_ms' => _1.begin_ms, 'end_ms' => _1.end_ms }
         } }
-        }
+    end
-
-    external_tag_snapshots =
-        post_external_tags.order(:external_tag_id).map {
-          { 'external_tag_id' => _1.external_tag_id }
-        }
-
-    tag_snapshots + external_tag_snapshots
   end
 
   def self.section_literal section

backend/app/models/post_external_tag.rb

@@ -1,4 +0,0 @@
-class PostExternalTag < ApplicationRecord
-  belongs_to :post
-  belongs_to :external_tag, counter_cache: :post_count
-end

backend/app/models/post_tag.rb

@@ -1,7 +1,14 @@
 class PostTag < ApplicationRecord
+  include Discard::Model
+
+  before_destroy do
+    raise ActiveRecord::ReadOnlyRecord, '消さないでください．'
+  end
+
   belongs_to :post
   belongs_to :tag, counter_cache: :post_count
   belongs_to :created_user, class_name: 'User', optional: true
+  belongs_to :deleted_user, class_name: 'User', optional: true
 
   has_many :sections, -> { order(:begin_ms) }, class_name: 'PostTagSection',
                                                foreign_key: [:post_id, :tag_id],
@@ -11,5 +18,18 @@ class PostTag < ApplicationRecord
 
   validates :post_id, presence: true
   validates :tag_id, presence: true
-  validates :post_id, uniqueness: { scope: :tag_id }
+  validates :post_id, uniqueness: {
+      scope: :tag_id,
+      conditions: -> { where(discarded_at: nil) } }
+
+  def discard_by! deleted_user
+    return self if discarded?
+
+    transaction do
+      update!(discarded_at: Time.current, deleted_user:)
+      Tag.where(id: tag_id).update_all('post_count = GREATEST(post_count - 1, 0)')
+    end
+
+    self
+  end
 end

backend/app/models/post_tag_section.rb

@@ -4,7 +4,7 @@ class PostTagSection < ApplicationRecord
   belongs_to :post
   belongs_to :tag
 
-  belongs_to :post_tag, foreign_key: [:post_id, :tag_id],
+  belongs_to :post_tag, -> { kept }, foreign_key: [:post_id, :tag_id],
                                      primary_key: [:post_id, :tag_id],
                                      inverse_of: :sections,
                                      optional: true

backend/app/models/region.rb

@@ -1,3 +0,0 @@
-class Region < ApplicationRecord
-  ;
-end

backend/app/models/script.rb

@@ -1,5 +0,0 @@
-class Script < ApplicationRecord
-  has_many :locales, foreign_key: :script_code, primary_key: :code
-
-  enum :code, Jpan: 'Jpan'
-end

backend/app/models/tag.rb

@@ -2,6 +2,8 @@ require 'set'
 
 
 class Tag < ApplicationRecord
+  include MyDiscard
+
   class NicoTagNormalisationError < ArgumentError
     ;
   end
@@ -26,12 +28,15 @@ class Tag < ApplicationRecord
   end
 
   has_many :post_tags, inverse_of: :tag
-  has_many :posts, through: :post_tags
+  has_many :active_post_tags, -> { kept }, class_name: 'PostTag', inverse_of: :tag
+  has_many :post_tags_with_discarded, -> { with_discarded }, class_name: 'PostTag'
+  has_many :posts, through: :active_post_tags
+
+  has_many :nico_tag_relations, foreign_key: :nico_tag_id, dependent: :destroy
+  has_many :linked_tags, through: :nico_tag_relations, source: :tag
 
   has_many :reversed_nico_tag_relations,
-           class_name: 'NicoTagRelation',
+           class_name: 'NicoTagRelation', foreign_key: :tag_id, dependent: :destroy
-           foreign_key: :tag_id,
-           dependent: :destroy
   has_many :linked_nico_tags, through: :reversed_nico_tag_relations, source: :nico_tag
 
   has_many :tag_implications, foreign_key: :parent_tag_id, dependent: :destroy
@@ -49,22 +54,32 @@ class Tag < ApplicationRecord
   has_many :materials
 
   has_many :tag_versions
+  has_many :nico_tag_versions
 
-  has_many :tag_names
+  belongs_to :tag_name
+  delegate :wiki_page, to: :tag_name
 
   attribute :version_no, :integer, default: 1
 
+  delegate :name, to: :tag_name, allow_nil: true
+  validates :tag_name, presence: true
+
   enum :category, deerjikist:  'deerjikist',
                   meme:        'meme',
                   character:   'character',
                   general:     'general',
                   material:    'material',
+                  nico:        'nico',
                   meta:        'meta'
 
   validates :category, presence: true, inclusion: { in: Tag.categories.keys }
 
+  validate :nico_tag_name_must_start_with_nico
+  validate :tag_name_must_be_canonical
   validate :category_must_be_deerjikist_with_deerjikists
-  validate :tag_names_must_be_valid
+  validate :nico_tags_cannot_be_deprecated
+
+  scope :nico_tags, -> { nico }
 
   CATEGORY_PREFIXES = {
       'general:'    => :general,
@@ -78,20 +93,8 @@ class Tag < ApplicationRecord
       'mtr:'        => :material,
       'meta:'       => :meta }.freeze
 
-  SYSTEM_TAG_NAMES = ['タグ希望', 'bot操作', 'ニジラー情報不詳', '動画', 'ニコニコ', 'YouTube'].freeze
+  def name= val
-
+    (self.tag_name ||= build_tag_name).name = val
-  def tag_name language_code
-    if tag_names.loaded?
-      tag_names.find { _1.language_code == language_code && _1.primary_flg }
-    else
-      tag_names.find_by(language_code:, primary_flg: true)
-    end
-  end
-  def name(language_code) = tag_name(language_code)&.name
-  def wiki_page = tag_name('ja')&.wiki_page
-
-  def system?
-    tag_name('ja')&.name.in?(SYSTEM_TAG_NAMES)
   end
 
   def deprecated? = deprecated_at?
@@ -102,35 +105,19 @@ class Tag < ApplicationRecord
 
   def has_deerjikists = deerjikists.loaded? ? deerjikists.any? : deerjikists.exists?
 
-  def snapshot_aliases(language_code)
+  def self.tagme = find_or_create_by_tag_name!('タグ希望', category: :meta)
-    tag_names.where(language_code:, primary_flg: false).order(:name).pluck(:name)
+  def self.bot = find_or_create_by_tag_name!('bot操作', category: :meta)
-  end
+  def self.no_deerjikist = find_or_create_by_tag_name!('ニジラー情報不詳', category: :meta)
+  def self.video = find_or_create_by_tag_name!('動画', category: :meta)
+  def self.niconico = find_or_create_by_tag_name!('ニコニコ', category: :meta)
+  def self.youtube = find_or_create_by_tag_name!('YouTube', category: :meta)
 
-  def snapshot_parent_tag_ids = parents.order(:id).pluck(:id)
+  def self.normalise_tags! tag_names, with_tagme: true,
-
-  def snapshot_linked_tag_names language_code
-    linked_tags
-        .joins(:tag_names)
-        .where(tag_names: { language_code:, primary_flg: true })
-        .order('tag_names.name')
-        .pluck('tag_names.name')
-  end
-
-  class << self
-    def tagme = find_or_create_by_tag_name!(Locale.nipponese, 'タグ希望', category: :meta)
-    def bot = find_or_create_by_tag_name!(Locale.nipponese, 'bot操作', category: :meta)
-    def no_deerjikist =
-        find_or_create_by_tag_name!(Locale.nipponese, 'ニジラー情報不詳', category: :meta)
-    def video = find_or_create_by_tag_name!(Locale.nipponese, '動画', category: :meta)
-    def niconico = find_or_create_by_tag_name!(Locale.nipponese, 'ニコニコ', category: :meta)
-    def youtube = find_or_create_by_tag_name!(Locale.nipponese, 'YouTube', category: :meta)
-
-    def normalise_tags! locale, tag_names,
-                             with_tagme: true,
                                       with_no_deerjikist: true,
+                                      deny_nico: true,
                                       deny_deprecated: false,
                                       with_sections: false
-      if tag_names.any? { |n| n.downcase.start_with?('nico:') }
+    if deny_nico && tag_names.any? { |n| n.downcase.start_with?('nico:') }
       raise NicoTagNormalisationError
     end
 
@@ -156,11 +143,11 @@ class Tag < ApplicationRecord
         raise SectionLiteralParseError.new(raw_name, raw_name)
       end
 
-        name = TagName.canonicalise(locale, name).first
+      name = TagName.canonicalise(name).first
 
-        find_or_create_by_tag_name!(locale, name, category: (cat || :general)).tap do |tag|
+      find_or_create_by_tag_name!(name, category: (cat || :general)).tap do |tag|
         if deny_deprecated && tag.deprecated?
-            raise DeprecatedTagNormalisationError, [tag.name(locale.language_code)]
+          raise DeprecatedTagNormalisationError, [tag.name]
         end
 
         tag.update!(category: cat) if cat && tag.category != cat
@@ -184,7 +171,7 @@ class Tag < ApplicationRecord
     end
   end
 
-    def expand_parent_tags tags
+  def self.expand_parent_tags tags
     return [] if tags.blank?
 
     seen = Set.new
@@ -207,7 +194,7 @@ class Tag < ApplicationRecord
     (result + tags).uniq { |t| t.id }
   end
 
-    def normalise_section_range! begin_raw:, end_raw:, tag_name:
+  def self.normalise_section_range! begin_raw:, end_raw:, tag_name:
     begin_ms = begin_raw.empty? ? 0 : time_to_ms!(begin_raw, tag_name:)
     end_ms = end_raw.empty? ? nil : time_to_ms!(end_raw, tag_name:)
 
@@ -219,7 +206,7 @@ class Tag < ApplicationRecord
     [begin_ms, end_ms]
   end
 
-    def merge_section_ranges ranges
+  def self.merge_section_ranges ranges
     sorted_ranges = ranges.sort_by { |begin_ms, end_ms| [begin_ms, end_ms || Float::INFINITY] }
     merged = []
 
@@ -240,37 +227,24 @@ class Tag < ApplicationRecord
     merged
   end
 
-    def merge_section_end left_end_ms, right_end_ms
+  def self.merge_section_end left_end_ms, right_end_ms
     return nil if left_end_ms.nil? || right_end_ms.nil?
 
     [left_end_ms, right_end_ms].max
   end
 
-    def find_or_create_by_tag_name! locale, name, category:
+  def self.find_or_create_by_tag_name! name, category:
-      language_code = locale.language_code
+    tn = TagName.find_undiscard_or_create_by!(name: name.to_s.strip)
-      name = name.to_s.strip
+    tn = tn.canonical if tn.canonical_id?
 
-      ApplicationRecord.transaction do
+    Tag.find_undiscard_or_create_by!(tag_name_id: tn.id) do |t|
-        tn = TagName.find_or_create_by!(language_code:, name:) do
+      t.category = category
-          _1.script_code = locale.script_code
-          _1.primary_flg = true
-        end
-
-        tag = tn.tag
-        next tag if tag
-
-        tag = Tag.create!(tag_name_id: tn.id, category:)
-        tn.update!(tag:, primary_flg: true, canonical_id: nil, auto_generated: false)
-        generate_tag_names!(locale, tag, tn)
-        tag.association(:tag_names).reset
-
-        tag
     end
   rescue ActiveRecord::RecordNotUnique
     retry
   end
 
-    def merge_tags! target_tag, source_tags, created_by_user: nil
+  def self.merge_tags! target_tag, source_tags, created_by_user: nil
     target_tag => Tag
 
     affected_post_ids = Set.new
@@ -285,28 +259,30 @@ class Tag < ApplicationRecord
 
         TagVersioning.ensure_snapshot!(source_tag, created_by_user:)
 
-          source_tag.post_tags.find_each do |source_pt|
+        source_tag.post_tags.kept.find_each do |source_pt|
           post_id = source_pt.post_id
           affected_post_ids << post_id
-            source_pt.destroy!
+          source_pt.discard_by!(created_by_user)
-            unless PostTag.exists?(post_id:, tag: target_tag)
+          unless PostTag.kept.exists?(post_id:, tag: target_tag)
             PostTag.create!(post_id:, tag: target_tag)
           end
         end
 
-          source_tag_name = source_tag.tag_name('ja')
+        source_tag_name = source_tag.tag_name
 
         if source_tag_name.wiki_page.present?
           raise ActiveRecord::RecordInvalid.new(source_tag_name)
         end
 
         TagVersioning.record!(source_tag, event_type: :discard, created_by_user:)
-          source_tag.tag_names.update_all(tag_id: target_tag.id, primary_flg: false,
+        source_tag.discard!
-                                          updated_at: Time.current)
-          source_tag.destroy!
 
+        if source_tag.nico?
+          source_tag_name.discard!
+        else
           source_tag_name.update_columns(canonical_id: target_tag.tag_name_id,
                                          updated_at: Time.current)
+        end
 
         TagVersioning.record!(target_tag, event_type: :update, created_by_user:)
       end
@@ -317,13 +293,43 @@ class Tag < ApplicationRecord
       end
 
       # 投稿件数を再集計
-        target_tag.update_columns(post_count: PostTag.where(tag: target_tag).count)
+      target_tag.update_columns(post_count: PostTag.kept.where(tag: target_tag).count)
     end
 
     target_tag.reload
   end
 
-    def time_to_ms! str, tag_name:
+  def snapshot_aliases = tag_name.aliases.kept.order(:name).pluck(:name)
+
+  def snapshot_parent_tag_ids = parents.order(:id).pluck(:id)
+
+  def snapshot_linked_tag_names
+    linked_tags.joins(:tag_name).order('tag_names.name').pluck('tag_names.name')
+  end
+
+  private
+
+  def nico_tag_name_must_start_with_nico
+    n = name.to_s
+    if ((nico? && !(n.downcase.start_with?('nico:'))) || 
+        (!(nico?) && n.downcase.start_with?('nico:')))
+      errors.add :name, 'ニコニコ・タグの命名規則に反してゐます．'
+    end
+  end
+
+  def tag_name_must_be_canonical
+    if tag_name&.canonical_id?
+      errors.add :tag_name, 'tag_names へは実体を示す必要があります．'
+    end
+  end
+
+  def category_must_be_deerjikist_with_deerjikists
+    if !(deerjikist?) && deerjikists.exists?
+      errors.add :category, 'ニジラーと紐づいてゐるタグはニジラー・カテゴリである必要があります．'
+    end
+  end
+
+  def self.time_to_ms! str, tag_name:
     match =
         case str
         when /\A(?<seconds>\d+)(?:\.(?<ms>\d{1,3}))?\z/
@@ -349,44 +355,9 @@ class Tag < ApplicationRecord
     total_s * 1_000 + match[:ms].to_s.ljust(3, '0')[0, 3].to_i
   end
 
-    private
+  def nico_tags_cannot_be_deprecated
-
+    if nico? && deprecated_at.present?
-    def generate_tag_names! locale, tag, base_tag_name
+      errors.add :deprecated_at, 'ニコタグは廃止できません．'
-      ApplicationRecord.transaction do
-        locales =
-            Locale
-            .where(deprecated_at: nil)
-            .where.not(language_code: locale.language_code)
-            .order(:language_code, :created_at, :script_code)
-            .uniq { _1.language_code }
-        locales.each do |locale|
-          language_code = locale.language_code
-          script_code = locale.script_code
-          TagName.create!(tag_id: tag.id,
-                          language_code:,
-                          name: TagName.generate_name(locale, tag, base_tag_name),
-                          script_code:,
-                          primary_flg: true,
-                          auto_generated: true,
-                          canonical_id: nil)
-        end
-      end
-    end
-  end
-
-  private
-
-  def tag_names_must_be_valid
-    tag_names.each do |tag_name|
-      next if tag_name.valid?
-
-      tag_name.errors[:name].each { errors.add :name, _1 }
-    end
-  end
-
-  def category_must_be_deerjikist_with_deerjikists
-    if !(deerjikist?) && deerjikists.exists?
-      errors.add :category, 'ニジラーと紐づいてゐるタグはニジラー・カテゴリである必要があります．'
     end
   end
 end

backend/app/models/tag_description.rb

@@ -1,3 +0,0 @@
-class TagDescription < ApplicationRecord
-  belongs_to :tag
-end

backend/app/models/tag_description_version.rb

@@ -1,3 +0,0 @@
-class TagDescriptionVersion < ApplicationRecord
-  ;
-end

backend/app/models/tag_group.rb

@@ -1,16 +0,0 @@
-class TagGroup < ApplicationRecord
-  belongs_to :created_by_user, class_name: 'User', optional: true
-  belongs_to :updated_by_user, class_name: 'User', optional: true
-
-  has_many :tag_group_tags, dependent: :delete_all
-  has_many :tags, through: :tag_group_tags
-  has_many :tag_group_groups, dependent: :delete_all
-  has_many :child_tag_groups, through: :tag_group_groups
-  has_many :placements, -> { order(:position) },
-           class_name: 'TagGroupPlacement', dependent: :delete_all
-  has_many :versions, -> { order(:version_no) },
-           class_name: 'TagGroupVersion', dependent: :delete_all
-
-  validates :name, presence: true, uniqueness: true, length: { maximum: 255 }
-  validates :version_no, numericality: { only_integer: true, greater_than: 0 }
-end

backend/app/models/tag_group_group.rb

@@ -1,7 +0,0 @@
-class TagGroupGroup < ApplicationRecord
-  self.primary_key = [:tag_group_id, :child_tag_group_id]
-
-  belongs_to :tag_group
-  belongs_to :child_tag_group, class_name: 'TagGroup'
-  belongs_to :created_by_user, class_name: 'User', optional: true
-end

backend/app/models/tag_group_placement.rb

@@ -1,9 +0,0 @@
-class TagGroupPlacement < ApplicationRecord
-  self.primary_key = [:tag_group_id, :position]
-
-  belongs_to :tag_group
-  belongs_to :tag, optional: true
-  belongs_to :child_tag_group, class_name: 'TagGroup', optional: true
-  belongs_to :created_by_user, class_name: 'User', optional: true
-  belongs_to :updated_by_user, class_name: 'User', optional: true
-end

backend/app/models/tag_group_tag.rb

@@ -1,7 +0,0 @@
-class TagGroupTag < ApplicationRecord
-  self.primary_key = [:tag_group_id, :tag_id]
-
-  belongs_to :tag_group
-  belongs_to :tag
-  belongs_to :created_by_user, class_name: 'User', optional: true
-end

backend/app/models/tag_group_version.rb

@@ -1,7 +0,0 @@
-class TagGroupVersion < ApplicationRecord
-  include VersionRecord
-
-  belongs_to :tag_group
-
-  scope :ordered, -> { order(:version_no) }
-end

backend/app/models/tag_name.rb

@@ -1,61 +1,45 @@
 class TagName < ApplicationRecord
-  belongs_to :language, foreign_key: :language_code, primary_key: :code
+  include MyDiscard
-  belongs_to :tag, optional: true
+
+  has_one :tag
   has_one :wiki_page
 
-  validates :name, presence: true,
+  belongs_to :canonical, class_name: 'TagName', optional: true
-                   length: { maximum: 255 },
+  has_many :aliases, class_name: 'TagName', foreign_key: :canonical_id
-                   uniqueness: { scope: :language_code }
 
+  validates :name, presence: true, length: { maximum: 255 }, uniqueness: true
+
+  validate :canonical_must_be_canonical
   validate :alias_name_must_not_have_prefix
-  validate :alias_must_not_have_wiki_page
+  validate :canonical_must_not_be_present_with_tag_or_wiki_page
   validate :name_must_be_sanitised
-  validate :name_mustnt_start_with_nico
-  validate :generated_name_must_be_reserved
 
-  def primary? = primary_flg
+  def self.canonicalise names
-
-  def self.canonicalise locale, names
     names = Array(names).map { |n| n.to_s.strip }.reject(&:blank?)
     return [] if names.blank?
 
-    tns = TagName.where(language_code: locale.language_code, name: names).index_by(&:name)
+    tns = TagName.includes(:canonical).where(name: names).index_by(&:name)
 
-    names.map { |name|
+    names.map { |name| tns[name]&.canonical&.name || name }.uniq
-      tag_name = tns[name]
-      if !tag_name || tag_name.primary? || tag_name.tag_id.nil?
-        name
-      else
-        TagName.find_by(language_code: locale.language_code,
-                        tag_id: tag_name.tag_id,
-                        primary_flg: true)&.name || name
-      end
-    }.uniq
-  end
-
-  def self.generate_name locale, tag, base_tag_name
-    # TODO: 言語ごとの自動命名ロジック完成したら書く．
-
-    "Tag_##{ tag.id }"
   end
 
   private
 
-  def generated_name_must_be_reserved
+  def canonical_must_be_canonical
-    if !auto_generated && name.to_s.start_with?('Tag_#')
+    if canonical&.canonical_id?
-      errors.add :name, 'タグの命名規則に反してゐます．'
+      errors.add :canonical, 'canonical は実体を示す必要があります．'
     end
   end
 
   def alias_name_must_not_have_prefix
-    if !(primary?) && name.to_s.include?(':')
+    if canonical_id? && name.to_s.include?(':')
       errors.add :name, 'エーリアス名にプレフィクスを含むことはできません．'
     end
   end
 
-  def alias_must_not_have_wiki_page
+  def canonical_must_not_be_present_with_tag_or_wiki_page
-    if !(primary?) && wiki_page
+    if canonical_id? && (tag || wiki_page)
-      errors.add :primary_flg, 'Wiki 参照がある名前はエーリアスになれません．'
+      errors.add :canonical, 'タグもしくは Wiki の参照がある名前はエーリアスになれません．'
     end
   end
 
@@ -64,10 +48,4 @@ class TagName < ApplicationRecord
       errors.add :name, '名前に使用できない文字が含まれてゐます．'
     end
   end
-
-  def name_mustnt_start_with_nico
-    if name.to_s.downcase.start_with?('nico:')
-      errors.add :name, 'タグの命名規則に反してゐます．'
-    end
-  end
 end

backend/app/models/tag_name_sanitisation_rule.rb

@@ -10,37 +10,29 @@ class TagNameSanitisationRule < ApplicationRecord
   validate :source_pattern_must_be_regexp
 
   class << self
-    def sanitise(name)
+    def sanitise(name) =
         rules.reduce(name.dup) { |name, (pattern, replacement)| name.gsub(pattern, replacement) }
-    end
 
     def apply!
-      Language.find_each do |language|
+      TagName.find_each do |tn|
-        TagName.where(language:).find_each do |tn|
         name = sanitise(tn.name)
         next if name == tn.name
 
         TagName.transaction do
-            existing_tn = TagName.find_by(language:, name:)
+          existing_tn = TagName.find_by(name:)
           if existing_tn
-              unless existing_tn.primary_flg
+            existing_tn = existing_tn.canonical || existing_tn
-                existing_tn = TagName.find_by!(language:,
-                                               tag_id: existing_tn.tag_id,
-                                               primary_flg: true)
-              end
             next if existing_tn.id == tn.id
 
-              existing_tag = existing_tn.tag
+            existing_tag = Tag.find_by(tag_name_id: existing_tn.id)
-              source_tag = tn.tag
+            source_tag = Tag.find_by(tag_name_id: tn.id)
 
             if existing_tag
               Tag.merge_tags!(existing_tag, source_tag) if tn.tag
             elsif source_tag
-                tn.update_columns(tag_id: nil, updated_at: Time.current)
               source_tag.update_columns(tag_name_id: existing_tn.id, updated_at: Time.current)
-                existing_tn.update_columns(tag_id: source_tag.id, updated_at: Time.current)
             end
-              tn.destroy!
+            tn.discard!
 
             next
           end
@@ -50,7 +42,6 @@ class TagNameSanitisationRule < ApplicationRecord
         end
       end
     end
-    end
 
     private
 

backend/app/models/tag_version.rb

@@ -11,6 +11,5 @@ class TagVersion < ApplicationRecord
                     meta: 'meta' }, validate: true
 
   validates :name, presence: true
-  validates :names, presence: true
   validates :category, presence: true
 end

backend/app/models/wiki_page.rb

@@ -48,11 +48,8 @@ class WikiPage < ApplicationRecord
     page
   end
 
-  def pred_revision_id revision_id
+  def pred_revision_id(revision_id) =
       wiki_revisions.where('id < ?', revision_id).order(id: :desc).limit(1).pick(:id)
-  end
+  def succ_revision_id(revision_id) =
-
-  def succ_revision_id revision_id
       wiki_revisions.where('id > ?', revision_id).order(id: :asc).limit(1).pick(:id)
 end
-end

backend/app/representations/deerjikist_repr.rb

@@ -6,12 +6,11 @@ module DeerjikistRepr
 
   module_function
 
-  def base deerjikist, language_code: 'ja'
+  def base deerjikist
-    deerjikist.as_json(BASE).merge(
+    deerjikist.as_json(BASE)
-        tag: deerjikist.tag && TagRepr.base(deerjikist.tag, language_code:))
   end
 
-  def many deerjikists, language_code: 'ja'
+  def many deerjikists
-    deerjikists.map { |d| base(d, language_code:) }
+    deerjikists.map { |d| base(d) }
   end
 end

backend/app/representations/external_tag_repr.rb

@@ -1,20 +0,0 @@
-module ExternalTagRepr
-  module_function
-
-  def base tag
-    { 'id' => tag.id,
-      'name' => "#{ tag.platform }:#{ tag.name }",
-      'category' => 'nico',
-      'post_count' => tag.post_count,
-      'created_at' => tag.created_at,
-      'updated_at' => tag.created_at,
-      'deprecated_at' => nil,
-      'aliases' => [],
-      'parents' => [],
-      'has_wiki' => false,
-      'material_id' => nil,
-      'has_deerjikists' => false }
-  end
-
-  def inline(tag) = base(tag)
-end

backend/app/representations/material_repr.rb

@@ -12,15 +12,14 @@ module MaterialRepr
 
   module_function
 
-  def base material, host:, language_code: 'ja'
+  def base material, host:
     material.as_json(BASE).merge(
-        tag: material.tag && TagRepr.base(material.tag, language_code:),
         file: if material.file.attached?
                 Rails.application.routes.url_helpers.rails_storage_proxy_url(
                     material.file, host:)
               end,
         thumbnail: thumbnail_url(material, host:),
-        thumbnail_fallback_text: thumbnail_fallback_text(material, language_code:),
+        thumbnail_fallback_text: thumbnail_fallback_text(material),
         thumbnail_fallback_kind: thumbnail_fallback_kind(material),
         media_kind: media_kind(material),
         file_byte_size: material.file_byte_size,
@@ -28,11 +27,11 @@ module MaterialRepr
         export_items: export_items(material))
   end
 
-  def many materials, host:, language_code: 'ja'
+  def many materials, host:
-    materials.map { |m| base(m, host:, language_code:) }
+    materials.map { |m| base(m, host:) }
   end
 
-  def list material, host:, language_code: 'ja'
+  def list material, host:
     { id: material.id,
       version_no: material.version_no,
       url: material.url,
@@ -41,9 +40,9 @@ module MaterialRepr
       source_path: material.source_path,
       source_file_id: material.source_file_id,
       normalized_source_key: material.normalized_source_key,
-      tag: compact_tag(material.tag, language_code:),
+      tag: compact_tag(material.tag),
       thumbnail: thumbnail_url(material, host:),
-      thumbnail_fallback_text: thumbnail_fallback_text(material, language_code:),
+      thumbnail_fallback_text: thumbnail_fallback_text(material),
       thumbnail_fallback_kind: thumbnail_fallback_kind(material),
       media_kind: media_kind(material),
       content_type: material.content_type,
@@ -54,8 +53,8 @@ module MaterialRepr
       export_items: export_items(material) }
   end
 
-  def list_many materials, host:, language_code: 'ja'
+  def list_many materials, host:
-    materials.map { |m| list(m, host:, language_code:) }
+    materials.map { |m| list(m, host:) }
   end
 
   def export_paths material
@@ -80,8 +79,8 @@ module MaterialRepr
         material.thumbnail, host:)
   end
 
-  def thumbnail_fallback_text material, language_code:
+  def thumbnail_fallback_text material
-    material.tag&.name(language_code) || material.created_at&.strftime('%Y-%m-%d')
+    material.tag&.name || material.created_at&.strftime('%Y-%m-%d')
   end
 
   def thumbnail_fallback_kind material
@@ -99,11 +98,11 @@ module MaterialRepr
     'file_other'
   end
 
-  def compact_tag tag, language_code:
+  def compact_tag tag
     return nil unless tag
 
     { id: tag.id,
-      name: tag.name(language_code),
+      name: tag.name,
       category: tag.category,
       deprecated_at: tag.deprecated_at }
   end

backend/app/representations/post_repr.rb

@@ -17,23 +17,23 @@ module PostRepr
 
   module_function
 
-  def base post, current_user = nil, host: nil, language_code: 'ja'
+  def base post, current_user = nil, host: nil
     json =
         if host.present?
           common(post, host:)
         else
           common(post)
         end
-    json['tags'] = tag_json(post, language_code:)
+    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
     json
   end
 
   def detail post, current_user = nil, parent_posts: [], child_posts: [],
-             sibling_posts: { }, related: [], host: nil, language_code: 'ja'
+             sibling_posts: { }, related: [], host: nil
     if host.present?
-      base(post, current_user, host:, language_code:).merge(
+      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|
@@ -41,7 +41,7 @@ module PostRepr
           },
           'related' => cards(related, host:))
     else
-      base(post, current_user, language_code:).merge(
+      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|
@@ -86,25 +86,16 @@ module PostRepr
                        end)
   end
 
-  def tag_json post, language_code:
+  def tag_json post
-    internal_tags =
     post
-        .post_tags
+        .active_post_tags
         .reject { _1.tag.deprecated? }
-        .sort_by { TagRepr.name_for(_1.tag, language_code) }
+        .sort_by { _1.tag.name }
         .map { |post_tag|
-          TagRepr.inline(post_tag.tag, language_code:).merge(
+      TagRepr.inline(post_tag.tag).merge(
           'children' => [],
           'sections' => post_tag.sections.as_json(only: [:begin_ms, :end_ms]))
     }
-
-    external_tags =
-        post
-        .external_tags
-        .sort_by { _1.name }
-        .map { ExternalTagRepr.base(_1).merge('children' => [], 'sections' => []) }
-
-    internal_tags + external_tags
   end
 
   def thumbnail_url post, host: nil

backend/app/representations/tag_group_repr.rb

@@ -1,194 +0,0 @@
-module TagGroupRepr
-  PREFIX = 'タググループ:'
-
-  module_function
-
-  def many groups
-    ids = groups.map(&:id)
-    return [] if ids.empty?
-
-    tag_members = TagGroupTag.where(tag_group_id: ids)
-        .group_by(&:tag_group_id)
-    group_members = TagGroupGroup.where(tag_group_id: ids)
-        .group_by(&:tag_group_id)
-    placements = TagGroupPlacement.where(tag_group_id: ids).order(:position)
-        .group_by(&:tag_group_id)
-
-    target_ids = tag_members.values.flatten.map(&:tag_id) +
-        group_members.values.flatten.map(&:child_tag_group_id) +
-        placements.values.flatten.filter_map(&:tag_id)
-    child_ids = group_members.values.flatten.map(&:child_tag_group_id) +
-        placements.values.flatten.filter_map(&:child_tag_group_id)
-    tags = Tag.select(:id, :category).where(id: target_ids.uniq).index_by(&:id)
-    names = TagName.where(tag_id: target_ids.uniq, language_code: 'ja', primary_flg: true)
-        .pluck(:tag_id, :name).to_h
-    child_groups = TagGroup.where(id: child_ids.uniq).index_by(&:id)
-
-    groups.map do |group|
-      group_json(group,
-                 tag_members.fetch(group.id, []),
-                 group_members.fetch(group.id, []),
-                 placements.fetch(group.id, []), tags, names, child_groups)
-    end
-  end
-
-  def one group
-    many([group]).first
-  end
-
-  def tag_group wiki_page
-    { 'id' => wiki_page.id,
-      'title' => "#{ PREFIX }#{ wiki_page.name }",
-      'deprecated_at' => nil,
-      'created_at' => wiki_page.created_at,
-      'updated_at' => wiki_page.updated_at }
-  end
-
-  def current_version group
-    TagGroupVersion.find_by(tag_group_id: group.id, version_no: group.version_no)
-  end
-
-  def historical version
-    members = Array(version.members)
-    placements = Array(version.placements)
-    tag_references = members.filter_map { |member| member['tag_id'] } +
-        collect_ids(placements, 'tag_id')
-    group_references = members.filter_map { |member| member['tag_group_id'] } +
-        collect_ids(placements, 'tag_group_id')
-    tag_versions = historical_tag_versions(tag_references)
-    group_versions = historical_group_versions(group_references)
-    tag_version_numbers = members.filter_map do |member|
-      next unless member['tag_id']
-
-      [member.fetch('tag_id'), member.fetch('version_no')]
-    end.to_h
-    group_version_numbers = members.filter_map do |member|
-      next unless member['tag_group_id']
-
-      [member.fetch('tag_group_id'), member.fetch('version_no')]
-    end.to_h
-    historical_members = members.map do |member|
-      historical_member(member, tag_versions, group_versions)
-    end
-    historical_placements = placements.map do |node|
-      historical_placement(node, tag_versions, group_versions,
-                           tag_version_numbers, group_version_numbers)
-    end
-    { 'id' => version.tag_group_id,
-      'name' => version.name,
-      'description' => version.description,
-      'version_no' => version.version_no,
-      'members' => historical_members,
-      'placements' => historical_placements,
-      'created_at' => version.created_at,
-      'updated_at' => version.created_at,
-      'created_by_user' => user_json(version.created_by_user),
-      'updated_by_user' => user_json(version.created_by_user) }
-  end
-
-  def group_json group, tag_members, group_members, rows, tags, names, child_groups
-    tree = placement_tree(rows, tags, names, child_groups)
-    members = tag_members.sort_by(&:tag_id).map do |member|
-      { 'tag' => tag_json(tags.fetch(member.tag_id), names.fetch(member.tag_id)) }
-    end
-    members.concat(group_members.sort_by(&:child_tag_group_id).map do |member|
-      { 'tag_group' => group_json_reference(child_groups.fetch(member.child_tag_group_id)) }
-    end)
-    { 'id' => group.id,
-      'name' => group.name,
-      'description' => group.description,
-      'version_no' => group.version_no,
-      'members' => members,
-      'placements' => tree,
-      'created_at' => group.created_at,
-      'updated_at' => group.updated_at,
-      'created_by_user' => user_json(group.created_by_user),
-      'updated_by_user' => user_json(group.updated_by_user) }
-  end
-
-  def user_json user
-    UserRepr.base(user) if user
-  end
-
-  def placement_tree rows, tags, names, child_groups
-    by_parent = rows.group_by(&:parent_position)
-    build = lambda do |parent|
-      by_parent.fetch(parent, []).sort_by(&:position).map do |row|
-        node = if row.tag_id
-          { 'tag' => tag_json(tags.fetch(row.tag_id), names.fetch(row.tag_id)) }
-        elsif row.child_tag_group_id
-          { 'tag_group' => group_json_reference(child_groups.fetch(row.child_tag_group_id)) }
-        else
-          { 'section_name' => row.section_name, 'description' => row.description }
-        end
-        node.merge('children' => build.call(row.position))
-      end
-    end
-    build.call(nil)
-  end
-
-  def tag_json tag, name
-    { 'id' => tag.id, 'name' => name, 'category' => tag.category }
-  end
-
-  def group_json_reference group
-    { 'id' => group.id, 'name' => group.name }
-  end
-
-  def collect_ids nodes, key
-    nodes.flat_map do |node|
-      [node[key], *collect_ids(Array(node['children']), key)].compact
-    end
-  end
-
-  def historical_tag_versions ids
-    TagVersion.where(tag_id: ids.uniq).to_a.index_by do |version|
-      [version.tag_id, version.version_no]
-    end
-  end
-
-  def historical_group_versions ids
-    TagGroupVersion.where(tag_group_id: ids.uniq).to_a.index_by do |version|
-      [version.tag_group_id, version.version_no]
-    end
-  end
-
-  def historical_member member, tag_versions, group_versions
-    if member['tag_id']
-      id = member.fetch('tag_id')
-      version = tag_versions.fetch([id, member.fetch('version_no')])
-      { 'tag' => { 'id' => id, 'name' => japanese_version_name(version),
-                   'category' => version.category } }
-    else
-      id = member.fetch('tag_group_id')
-      version = group_versions.fetch([id, member.fetch('version_no')])
-      { 'tag_group' => { 'id' => id, 'name' => version.name } }
-    end
-  end
-
-  def historical_placement(node, tag_versions, group_versions,
-                           tag_version_numbers, group_version_numbers)
-    result = if node['tag_id']
-      id = node.fetch('tag_id')
-      version_no = tag_version_numbers.fetch(id)
-      version = tag_versions.fetch([id, version_no])
-      { 'tag' => { 'id' => id, 'name' => japanese_version_name(version),
-                   'category' => version.category } }
-    elsif node['tag_group_id']
-      id = node.fetch('tag_group_id')
-      version_no = group_version_numbers.fetch(id)
-      version = group_versions.fetch([id, version_no])
-      { 'tag_group' => { 'id' => id, 'name' => version.name } }
-    else
-      { 'section_name' => node.fetch('section_name'), 'description' => node['description'] }
-    end
-    result.merge('children' => Array(node['children']).map do |child|
-      historical_placement(child, tag_versions, group_versions,
-                           tag_version_numbers, group_version_numbers)
-    end)
-  end
-
-  def japanese_version_name version
-    version.names.fetch('ja').fetch('name')
-  end
-end

backend/app/representations/tag_repr.rb

@@ -3,23 +3,18 @@
 
 module TagRepr
   BASE = { only: [:id, :category, :post_count, :created_at, :updated_at, :deprecated_at],
-           methods: [:has_wiki, :material_id, :has_deerjikists] }.freeze
+           methods: [:name, :has_wiki, :material_id, :has_deerjikists] }.freeze
 
   module_function
 
-  def base tag, language_code: 'ja'
+  def base tag
-    tag.as_json(BASE).merge(name: name_for(tag, language_code),
+    tag.as_json(BASE).merge(aliases: tag.snapshot_aliases,
-                            aliases: tag.snapshot_aliases(language_code),
+                            parents: tag.parents.map { _1.as_json(BASE) })
-                            parents: tag.parents.map { inline(_1, language_code:) })
   end
 
-  def inline tag, language_code: 'ja'
+  def inline tag
-    tag.as_json(BASE).merge(name: name_for(tag, language_code), aliases: [], parents: [])
+    tag.as_json(BASE).merge(aliases: [], parents: [])
   end
 
-  def many(tags, language_code: 'ja') = tags.map { |tag| base(tag, language_code:) }
+  def many(tags) = tags.map { |t| base(t) }
-
-  def name_for tag, language_code
-    tag.name(language_code) || (tag.system? ? tag.name('ja') : nil)
-  end
 end

backend/app/representations/wiki_page_repr.rb

@@ -10,25 +10,6 @@ module WikiPageRepr
     wiki_page.as_json(BASE)
   end
 
-  def tag_description description
-    tag = description.tag
-    { 'id' => description.id,
-      'tag_name_id' => tag.tag_name('ja')&.id,
-      'body' => description.body,
-      'created_user_id' => description.created_by_user_id,
-      'updated_user_id' => description.updated_by_user_id,
-      'created_at' => description.created_at,
-      'updated_at' => description.updated_at,
-      'discarded_at' => nil,
-      'version_no' => description.version_no,
-      'title' => tag.name('ja'),
-      'deprecated_at' => tag.deprecated_at }
-  end
-
-  def tag_group tag_group
-    TagGroupRepr.tag_group(tag_group)
-  end
-
   def many wiki_pages
     wiki_pages.map { |p| base(p) }
   end

backend/app/services/material_version_recorder.rb

@@ -31,7 +31,7 @@ class MaterialVersionRecorder < VersionRecorder
     { url: @record.url,
       parent: @record.parent,
       tag: @record.tag,
-      tag_name: @record.tag&.name('ja'),
+      tag_name: @record.tag&.name,
       tag_category: @record.tag&.category,
       source_kind: @record.source_kind,
       source_uri: @record.source_uri,

backend/app/services/nico_tag_version_recorder.rb

@@ -1,22 +1,19 @@
 class NicoTagVersionRecorder < VersionRecorder
-  def self.record! external_tag:, event_type:, created_by_user:
+  def self.record! tag:, event_type:, created_by_user:
-    new(external_tag:, event_type:, created_by_user:).record!
+    new(tag:, event_type:, created_by_user:).record!
   end
 
-  def initialize external_tag:, event_type:, created_by_user:
+  def initialize tag:, event_type:, created_by_user:
-    super(record: external_tag, event_type:, created_by_user:)
+    super(record: tag, event_type:, created_by_user:)
   end
 
   private
 
   def version_class = NicoTagVersion
   def version_association = :nico_tag_versions
-  def record_key = :external_tag
+  def record_key = :tag
 
   def snapshot_attributes
-    { name: "#{ @record.platform }:#{ @record.name }",
+    { name: @record.name, linked_tags: @record.snapshot_linked_tag_names.join(' ') }
-      linked_tags: @record.snapshot_linked_tag_names.join(' ') }
   end
-
-  def tracks_version_no_on_record? = false
 end

backend/app/services/post_bulk_creator.rb

@@ -6,7 +6,7 @@ class PostBulkCreator
     @host = host
   end
 
-  def run locale
+  def run
     results = Array.new(@posts.length)
     mutex = Mutex.new
     next_index = 0
@@ -27,7 +27,7 @@ class PostBulkCreator
                 break if index >= @posts.length
 
                 attributes = @posts[index]
-                results[index] = create_row(locale, actor, attributes, index)
+                results[index] = create_row(actor, attributes, index)
               rescue StandardError => e
                 Rails.logger.error(
                     "post_bulk_creator_worker_failure #{ { error: e.class.name,
@@ -61,12 +61,12 @@ class PostBulkCreator
 
   private
 
-  def create_row locale, actor, attributes, index
+  def create_row actor, attributes, index
     preflight =
         PostCreatePreflight.new(
             attributes: attributes,
             thumbnail: thumbnail_for(index, attributes),
-            host: @host).run(locale)
+            host: @host).run
     if preflight[:existing_post_id].present?
       return {
           status: 'skipped',
@@ -76,7 +76,7 @@ class PostBulkCreator
 
     post = PostCreator.new(
         actor: actor,
-        attributes: normalised_attributes(attributes, preflight, index)).create!(locale)
+        attributes: normalised_attributes(attributes, preflight, index)).create!
     result = {
         status: 'created',
         post: { id: post.id } }

backend/app/services/post_create_plan.rb

@@ -8,19 +8,20 @@ class PostCreatePlan
     @existing_tags_by_name = nil
   end
 
-  def build! locale
+  def build!
-    direct_tag_specs, tag_sections = parse_direct_tag_specs(locale)
+    direct_tag_specs, tag_sections = parse_direct_tag_specs
-    default_tag_specs = build_default_tag_specs(locale, 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!(locale, snapshot_tag_specs.map { _1[:name] })
+    preload_existing_tags_by_name!(snapshot_tag_specs.map { _1[:name] })
-    validate_new_tag_specs!(locale, snapshot_tag_specs)
+    validate_new_tag_specs!(snapshot_tag_specs)
-    post_tag_specs = expand_parent_tag_specs(locale, 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],
+    {
+        url: @attributes[:url],
         title: @attributes[:title].to_s,
         thumbnail_base: @attributes[:thumbnail_base].presence,
         original_created_from: @attributes[:original_created_from].presence,
@@ -42,16 +43,15 @@ class PostCreatePlan
 
   def tag_names = @attributes[:tags].to_s.split
 
-  def parse_direct_tag_specs locale
+  def parse_direct_tag_specs
     tag_sections = { }
     direct_tag_specs = []
 
     tag_names.each do |raw_name|
-      tag_name, category, sections = parse_raw_tag_name(locale, raw_name)
+      tag_name, category, sections = parse_raw_tag_name(raw_name)
-      existing_tag = existing_tags_by_name(locale)[tag_name]
+      existing_tag = existing_tags_by_name[tag_name]
-      if existing_tag&.deprecated?
+      raise Tag::NicoTagNormalisationError if existing_tag&.nico?
-        raise Tag::DeprecatedTagNormalisationError, [existing_tag.name(locale.language_code)]
+      raise Tag::DeprecatedTagNormalisationError, [existing_tag.name] if existing_tag&.deprecated?
-      end
 
       direct_tag_specs << {
           name: tag_name,
@@ -67,7 +67,7 @@ class PostCreatePlan
     [merge_tag_specs(direct_tag_specs), tag_sections]
   end
 
-  def parse_raw_tag_name locale, raw_name
+  def parse_raw_tag_name raw_name
     name = raw_name.to_s
     prefix, category =
         Tag::CATEGORY_PREFIXES.find {
@@ -76,7 +76,7 @@ class PostCreatePlan
     name = name.sub(/\A#{ prefix }/i, '')
 
     sections = []
-    while match = name.match(/\A(\S*?)\[([^\[\]\s]*)-([^\[\]\s]*)\](\S*)\z/)
+    while (match = name.match(/\A(\S*?)\[([^\[\]\s]*)-([^\[\]\s]*)\](\S*)\z/))
       name = "#{ match[1] }#{ match[4] }"
       next if match[2].empty? && match[3].empty?
 
@@ -89,17 +89,17 @@ class PostCreatePlan
       raise Tag::SectionLiteralParseError.new(raw_name, raw_name)
     end
 
-    [resolved_tag_name(locale, name), category&.to_sym, sections]
+    [resolved_tag_name(name), category&.to_sym, sections]
   end
 
-  def build_default_tag_specs locale, direct_tag_specs
+  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?(locale, _1) }
+    if direct_tag_specs.none? { deerjikist_tag_spec?(_1) }
       default_tag_specs << {
           name: NO_DEERJIKIST_TAG_NAME,
           category: :meta }
@@ -108,18 +108,17 @@ class PostCreatePlan
     default_tag_specs
   end
 
-  def validate_new_tag_specs! locale, specs
+  def validate_new_tag_specs! specs
     Array(specs).each do |spec|
-      next if existing_tags_by_name(locale).key?(spec[:name])
+      next if existing_tags_by_name.key?(spec[:name])
 
-      validate_new_tag_spec!(locale, spec)
+      validate_new_tag_spec!(spec)
     end
   end
 
-  def validate_new_tag_spec! locale, spec
+  def validate_new_tag_spec! spec
-    tag_name = TagName.new(name: spec[:name], language_code: locale.language_code,
+    tag_name = TagName.new(name: spec[:name])
-                           script_code: locale.script_code, primary_flg: true)
+    tag = Tag.new(category: spec[:category], tag_name:)
-    tag = Tag.new(category: spec[:category])
     return if tag_name.valid? && tag.valid?
 
     post = Post.new
@@ -134,22 +133,20 @@ class PostCreatePlan
     raise ActiveRecord::RecordInvalid, post
   end
 
-  def expand_parent_tag_specs locale, snapshot_tag_specs
+  def expand_parent_tag_specs snapshot_tag_specs
-    existing_snapshot_tags = snapshot_tag_specs.filter_map do
+    existing_snapshot_tags = snapshot_tag_specs.filter_map { existing_tags_by_name[_1[:name]] }
-      existing_tags_by_name(locale)[_1[:name]]
-    end
     expanded_parent_specs =
         Tag.expand_parent_tags(existing_snapshot_tags)
            .reject(&:deprecated?)
            .map { |tag|
-             { name: tag.name(locale.language_code),
+             {
-               category: tag.category.to_sym }
+                 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({ }) { |spec, merged|
+    specs.each_with_object({ }) do |spec, merged|
       merged[spec[:name]] =
           if merged.key?(spec[:name]) && merged[spec[:name]][:category] != :general
             merged[spec[:name]]
@@ -158,40 +155,36 @@ class PostCreatePlan
                 name: spec[:name],
                 category: spec[:category] }
           end
-    }.values.sort_by { _1[:name] }
+    end.values.sort_by { _1[:name] }
   end
 
-  def existing_tags_by_name locale
+  def existing_tags_by_name
     @existing_tags_by_name ||= begin
-      names = tag_names.map { canonical_tag_name_without_sections(locale, _1) }.uniq
+      names = tag_names.map { canonical_tag_name_without_sections(_1) }.uniq
-      TagName.where(language_code: locale.language_code, primary_flg: true, name: names)
+      Tag.joins(:tag_name).where(tag_names: { name: names }).index_by(&:name)
-             .includes(:tag)
-             .each_with_object({ }) { |tag_name, tags| tags[tag_name.name] = tag_name.tag }
     end
   end
 
-  def preload_existing_tags_by_name! locale, names
+  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(locale).keys
+    missing_names = wanted_names - existing_tags_by_name.keys
     return if missing_names.empty?
 
-    existing_tags_by_name(locale).merge!(
+    existing_tags_by_name.merge!(
-        TagName.where(language_code: locale.language_code,
+        Tag.joins(:tag_name)
-                      primary_flg: true,
+           .where(tag_names: { name: missing_names })
-                      name: missing_names)
+           .index_by(&:name))
-               .includes(:tag)
-               .each_with_object({ }) { |tag_name, tags| tags[tag_name.name] = tag_name.tag })
   end
 
-  def canonical_tag_name_without_sections locale, raw_name
+  def canonical_tag_name_without_sections raw_name
-    name, = parse_raw_tag_name(locale, raw_name)
+    name, = parse_raw_tag_name(raw_name)
     name
   end
 
-  def deerjikist_tag_spec? locale, spec
+  def deerjikist_tag_spec? spec
     return true if spec[:category] == :deerjikist
 
-    existing_tags_by_name(locale)[spec[:name]]&.deerjikist?
+    existing_tags_by_name[spec[:name]]&.deerjikist?
   end
 
   def normalise_parent_post_ids
@@ -269,12 +262,10 @@ class PostCreatePlan
     end
   end
 
-  def resolved_tag_name locale, name
+  def resolved_tag_name name
-    tag_name = TagName.find_by(language_code: locale.language_code, name:)
+    tag_name = TagName.includes(:canonical).find_by(name:)
-    return name if !(tag_name) || tag_name.primary?
+    return name if tag_name.nil?
 
-    TagName.find_by(language_code: locale.language_code,
+    (tag_name.canonical || tag_name).name
-                    tag_id: tag_name.tag_id,
-                    primary_flg: true)&.name || name
   end
 end

backend/app/services/post_create_preflight.rb

@@ -15,10 +15,9 @@ class PostCreatePreflight
     @host = host
   end
 
-  def run locale
+  def run
     preview = PostImportPreviewer.new.preview_rows(
         rows: [preview_row],
-        locale:,
         fetch_metadata: false).first
     if preview[:existing_post_id].present?
       return {
@@ -54,7 +53,7 @@ class PostCreatePreflight
             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!(locale)
+            video_ms: preview[:attributes]['video_ms'] }).build!
 
     {
         url: plan[:url],

backend/app/services/post_creator.rb

@@ -9,7 +9,7 @@ class PostCreator
     @field_warnings = { }
   end
 
-  def create! locale
+  def create!
     thumbnail_attachment = prepare_thumbnail_attachment
     post = Post.new(title: @attributes[:title].presence,
                     url: @attributes[:url],
@@ -21,17 +21,14 @@ class PostCreator
     ApplicationRecord.transaction do
       post.save!
       post.thumbnail.attach(thumbnail_attachment) if thumbnail_attachment.present?
-      snapshot_tags = planned_snapshot_tags(locale)
+      snapshot_tags = planned_snapshot_tags
-      post_tags = planned_post_tags(locale)
+      post_tags = planned_post_tags
-      sections = planned_sections(locale)
+      sections = planned_sections
-      TagVersioning.record_tag_snapshots!(
+      TagVersioning.record_tag_snapshots!(snapshot_tags, created_by_user: @actor)
-          snapshot_tags,
+      post.video_ms = planned_video_ms
-          created_by_user: @actor,
-          language_code: locale.language_code)
-      post.video_ms = planned_video_ms(locale)
       post.save!
       sync_post_tags!(post, post_tags, sections)
-      sync_parent_posts!(post, planned_parent_post_ids(locale))
+      sync_parent_posts!(post, planned_parent_post_ids)
       PostVersionRecorder.record!(post:, event_type: :create, created_by_user: @actor)
     end
     post
@@ -48,73 +45,69 @@ class PostCreator
         thumbnail_base: @attributes[:thumbnail_base].presence)
   end
 
-  def planned_snapshot_tags(locale) = planned_create_attributes(locale)[:snapshot_tags]
+  def planned_snapshot_tags = planned_create_attributes[:snapshot_tags]
 
-  def planned_post_tags(locale) = planned_create_attributes(locale)[:post_tags]
+  def planned_post_tags = planned_create_attributes[:post_tags]
 
-  def planned_sections(locale) = planned_create_attributes(locale)[:tag_sections]
+  def planned_sections = planned_create_attributes[:tag_sections]
 
-  def planned_parent_post_ids locale
+  def planned_parent_post_ids = planned_create_attributes[:normalised_parent_post_ids]
-    planned_create_attributes(locale)[:normalised_parent_post_ids]
+
+  def planned_video_ms
+    planned_create_attributes[:video_ms]
   end
 
-  def planned_video_ms locale
+  def planned_create_attributes
-    planned_create_attributes(locale)[:video_ms]
-  end
-
-  def planned_create_attributes locale
     @planned_create_attributes ||= begin
       if @attributes.key?(:snapshot_tag_specs)
-        snapshot_tags = materialise_tags(locale, @attributes[:snapshot_tag_specs] || [])
+        snapshot_tags = materialise_tags(@attributes[:snapshot_tag_specs] || [])
-        post_tags = materialise_tags(locale, @attributes[:post_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,
+                post_tags),
-                locale),
             normalised_parent_post_ids: @attributes[:normalised_parent_post_ids] || [],
             video_ms: @attributes[:video_ms] }
       else
-        build_materialised_plan(locale)
+        build_materialised_plan
       end
     end
   end
 
-  def build_materialised_plan locale
+  def build_materialised_plan
-    plan = PostCreatePlan.new(attributes: @attributes).build!(locale)
+    plan = PostCreatePlan.new(attributes: @attributes).build!
-    snapshot_tags = materialise_tags(locale, plan[:snapshot_tag_specs] || [])
+    snapshot_tags = materialise_tags(plan[:snapshot_tag_specs] || [])
-    post_tags = materialise_tags(locale, plan[:post_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,
+            post_tags),
-            locale),
         normalised_parent_post_ids: plan[:normalised_parent_post_ids] || [],
         video_ms: plan[:video_ms] }
   end
 
-  def materialise_tags locale, specs
+  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!(locale, name, category:)
+      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, locale = Locale.nipponese
+  def materialise_sections sections_by_name, snapshot_tags, post_tags
-    tags_by_name = post_tags.index_by { _1.name(locale.language_code) }
+    tags_by_name = post_tags.index_by(&:name)
     snapshot_tags.each do |tag|
-      tags_by_name[tag.name(locale.language_code)] ||= tag
+      tags_by_name[tag.name] ||= tag
     end
 
     sections_by_name.each_with_object({ }) do |(tag_name, ranges), sections|
@@ -128,11 +121,9 @@ class PostCreator
   def sync_post_tags! post, desired_tags, sections
     desired_ids = desired_tags.map(&:id).to_set
     current_ids = post.tags.pluck(:id).to_set
-
     Tag.where(id: desired_ids - current_ids).find_each do |tag|
       PostTag.create_or_find_by!(post:, tag:, created_user: @actor)
     end
-
     PostTagSection.where(post_id: post.id).destroy_all
     sections.each do |tag_id, ranges|
       ranges.each do |begin_ms, end_ms|
@@ -142,9 +133,10 @@ class PostCreator
                                end_ms:)
       end
     end
-
     PostTag.where(post_id: post.id,
-                  tag_id: (current_ids - desired_ids).to_a).destroy_all
+                  tag_id: (current_ids - desired_ids).to_a).kept.find_each do |post_tag|
+      post_tag.discard_by!(@actor)
+    end
   end
 
   def sync_parent_posts! post, ids

backend/app/services/post_import_previewer.rb

@@ -16,7 +16,7 @@ class PostImportPreviewer
   THUMBNAIL_FETCH_WARNING = 'サムネール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:, locale: Locale.nipponese, fetch_metadata: true, metadata_cache: { }
+  def preview_rows rows:, fetch_metadata: true, metadata_cache: { }
     prepared_rows = rows.map { prepare_row(_1) }
     url_counts = prepared_rows.filter_map { _1[:normal_url] }.tally
     existing_posts =
@@ -30,14 +30,13 @@ class PostImportPreviewer
         url_counts)
     known_tags =
         preload_known_tags(
-            locale,
             prepared_rows,
             fetch_metadata,
             metadata_cache,
             existing_posts,
             url_counts)
     prepared_rows.map { |row|
-      preview_row(locale, row,
+      preview_row(row,
                   fetch_metadata:,
                   metadata_cache:,
                   existing_posts:,
@@ -60,7 +59,7 @@ class PostImportPreviewer
     source.merge(url_text: url, normal_url:, url_error: validate_url_safety(normal_url))
   end
 
-  def preview_row locale, row,
+  def preview_row row,
                   fetch_metadata:,
                   metadata_cache:,
                   existing_posts:,
@@ -125,8 +124,7 @@ class PostImportPreviewer
 
     attributes['url'] = url
     validate_basic_data(attributes, validation_errors)
-    validate_preview_tags(locale,
+    validate_preview_tags(merged_tags(tag_sources, provenance['tags']),
-                          merged_tags(tag_sources, provenance['tags']),
                           validation_errors,
                           known_tags)
     validate_parents(attributes['parent_post_ids'], validation_errors, existing_parent_ids)
@@ -348,7 +346,7 @@ class PostImportPreviewer
     { data: { }, warnings: { 'url' => [METADATA_FETCH_WARNING] }, validation_errors: { } }
   end
 
-  def preload_known_tags locale, prepared_rows, fetch_metadata, metadata_cache, existing_posts, url_counts
+  def preload_known_tags prepared_rows, fetch_metadata, metadata_cache, existing_posts, url_counts
     names = prepared_rows.flat_map { |row|
       attributes = initial_attributes(row)
       provenance = initial_provenance(row)
@@ -360,13 +358,15 @@ class PostImportPreviewer
         metadata = metadata_for(row[:normal_url], metadata_cache)
         apply_metadata!(attributes, provenance, tag_sources, metadata[:data])
       end
-      preview_tag_names(locale, merged_tags(tag_sources, provenance['tags']))
+      preview_tag_names(merged_tags(tag_sources, provenance['tags']))
     }.compact.uniq
     return { } if names.empty?
 
-    TagName.where(language_code: locale.language_code, primary_flg: true, name: names)
+    Tag.joins(:tag_name)
-           .includes(:tag)
+      .where(tag_names: { name: names })
-           .each_with_object({ }) { |tag_name, tags| tags[tag_name.name] = tag_name.tag }
+      .includes(:tag_name)
+      .to_a
+      .index_by(&:name)
   end
 
   def preload_parent_ids prepared_rows
@@ -437,21 +437,19 @@ class PostImportPreviewer
     sources['automatic'].to_s
   end
 
-  def preview_tag_names locale, raw
+  def preview_tag_names raw
     names = raw.to_s.split
     return [] if names.empty?
     if names.any? { _1.downcase.start_with?('nico:') }
       return []
     end
 
-    names.map { |name|
+    names.map { |name| TagName.canonicalise(name.sub(/\[.*\]\z/, '')).first }
-      TagName.canonicalise(locale, name.sub(/\[.*\]\z/, '')).first
-    }
   rescue Tag::SectionLiteralParseError
     []
   end
 
-  def validate_preview_tags locale, raw, errors, 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:') }
@@ -459,11 +457,9 @@ class PostImportPreviewer
       return
     end
 
-    parsed = names.map { |name|
+    parsed = names.map { |name| TagName.canonicalise(name.sub(/\[.*\]\z/, '')).first }
-      TagName.canonicalise(locale, name.sub(/\[.*\]\z/, '')).first
-    }
     existing = parsed.filter_map { known_tags[_1] }
-    deprecated = existing.select(&:deprecated?).map { _1.name(locale.language_code) }
+    deprecated = existing.select(&:deprecated?).map(&:name)
     errors[:tags] = ["廃止済みタグがあります: #{ deprecated.join(' ') }"] if deprecated.present?
   rescue Tag::SectionLiteralParseError
     errors[:tags] = ['タグ区間の記法が不正です．']

backend/app/services/post_metadata_fetcher.rb

@@ -47,9 +47,9 @@ class PostMetadataFetcher
 
     existing_tags =
         Tag
-        .joins(:tag_names)
+        .joins(:tag_name)
-        .where(tag_names: { language_code: 'ja', primary_flg: true, name: names })
+        .where(tag_names: { name: names })
-        .index_by { _1.name('ja') }
+        .index_by(&:name)
 
     names.map { |name|
       tag = existing_tags[name]

backend/app/services/tag_description_operation.rb

@@ -1,54 +0,0 @@
-class TagDescriptionOperation
-  LANGUAGE_CODE = 'ja'
-
-  def self.create!(tag:, body:, created_by_user:, message: nil)
-    ApplicationRecord.transaction do
-      tag.lock!
-      raise ActiveRecord::RecordNotUnique if TagDescription.exists?(
-          tag_id: tag.id, language_code: LANGUAGE_CODE)
-
-      page = Wiki::CompatibilityWriter.create!(
-          tag_name: tag.tag_name(LANGUAGE_CODE), body:, created_by_user:, message:)
-      revision = page.wiki_revisions.order(id: :desc).first
-      record_version!(tag:, revision:, body:, user: created_by_user,
-                      description: nil)
-      page
-    end
-  end
-
-  def self.update!(tag:, body:, updated_by_user:, message: nil,
-                   base_revision_id: nil)
-    ApplicationRecord.transaction do
-      tag.lock!
-      description = TagDescription.lock.find_by!(
-          tag_id: tag.id, language_code: LANGUAGE_CODE)
-      page = WikiPage.lock.find(description.id)
-      revision = Wiki::CompatibilityWriter.update!(
-          page:, body:, updated_by_user:, message:,
-          base_revision_id:)
-      next unless revision
-
-      record_version!(tag:, revision:, body: revision.body,
-                      user: updated_by_user, description:)
-      revision
-    end
-  end
-
-  def self.record_version! tag:, revision:, body:, user:, description:
-    version_no = description ? description.version_no + 1 : 1
-    TagDescriptionVersion.create!(
-        id: revision.id, tag_id: tag.id, language_code: LANGUAGE_CODE,
-        version_no:, event_type: description ? 'update' : 'create', body:,
-        created_by_user_id: user.id, created_at: revision.created_at)
-    if description
-      description.update!(body:, version_no:, updated_by_user_id: user.id)
-    else
-      TagDescription.create!(
-          id: revision.wiki_page_id, tag_id: tag.id,
-          language_code: LANGUAGE_CODE, version_no:, body:,
-          created_by_user_id: user.id, updated_by_user_id: user.id)
-    end
-  end
-
-  private_class_method :record_version!
-end

backend/app/services/tag_group_markdown_parser.rb

@@ -1,177 +0,0 @@
-require 'kramdown'
-
-class TagGroupMarkdownParser
-  PREFIX = TagGroupRepr::PREFIX
-
-  class InvalidDocument < StandardError
-    ;
-  end
-
-  def self.parse(body:, group: nil)
-    new(body:, group:).parse
-  end
-
-  def initialize(body:, group:)
-    @body = body.to_s.gsub(/\r\n?/, "\n")
-    @group = group
-  end
-
-  def parse
-    parse_body = @body.gsub(/([^\n])\n([\x23]{1,6}[ \t]+\S)/, "\\1\n\n\\2")
-    root = Kramdown::Document.new(parse_body, input: 'GFM', auto_ids: false).root
-    placements = []
-    description_parts = []
-    headings = []
-
-    root.children.each do |node|
-      case node.type
-      when :blank
-        next
-      when :header
-        level = node.options.fetch(:level)
-        name = inline_text(node).strip
-        invalid!('Section 名は必須です．') if name.blank?
-
-        headings.pop while headings.any? && headings.last.fetch(:level) >= level
-        parent = headings.last&.fetch(:node)
-        section = { 'section_name' => name, 'description' => nil,
-                    'children' => [] }
-        (parent ? parent.fetch('children') : placements) << section
-        headings << { level:, node: section }
-      when :p
-        text = inline_markdown(node).strip
-        next if text.empty?
-
-        if headings.any?
-          section = headings.last.fetch(:node)
-          section['description'] = [section['description'], text].compact.join("\n\n")
-        else
-          description_parts << text
-        end
-      when :ul
-        invalid!('未対応のリスト項目があります．') if node.attr.any?
-        target = headings.any? ? headings.last.fetch(:node).fetch('children') : placements
-        target.concat(node.children.map { parse_list_item(_1) })
-      else
-        invalid!("未対応の Markdown 構文 #{ node.type.inspect } です．")
-      end
-    end
-
-    description = description_parts.presence&.join("\n\n")
-    { description:, placements:, members: build_members(placements),
-      compatibility_body: @body.sub(/\n+\z/, '') }
-  rescue Kramdown::Error => error
-    invalid!("Markdown を解析できません：#{ error.message }")
-  end
-
-  private
-
-  def parse_list_item(item)
-    invalid!('リスト項目ではありません．') unless item.type == :li
-    invalid!('未対応のリスト項目があります．') if item.attr.any?
-
-    nested, own = item.children.partition { |child| child.type == :ul }
-    invalid!('順序付きリストは使用できません．') if own.any? { _1.type == :ol }
-    own.reject! { _1.type == :blank }
-    invalid!('未対応のリスト項目があります．') unless own.all? do |child|
-      [:p, :text].include?(child.type)
-    end
-    invalid!('リスト項目は一つの段落で指定してください．') if own.size != 1
-
-    label = own.map { inline_text(_1) }.join(' ').strip
-    invalid!('空のリスト項目は使用できません．') if label.blank?
-
-    node = if label.start_with?(PREFIX)
-      group_name = label.delete_prefix(PREFIX).strip
-      child_group = TagGroup.find_by(name: group_name)
-      invalid!("Tag Group #{ group_name.inspect } を解決できません．") unless child_group
-      invalid!('自分自身を含めることはできません．') if child_group.id == @group&.id
-      { 'tag_group_id' => child_group.id }
-    elsif label.end_with?(':', '：')
-      section_name = label.sub(/[:：]\z/, '').strip
-      invalid!('Section 名は必須です．') if section_name.blank?
-      { 'section_name' => section_name, 'description' => nil }
-    else
-      { 'tag_id' => resolve_tag(label) }
-    end
-
-    node['children'] = nested.flat_map do |list|
-      invalid!('未対応の入れ子リストです．') unless list.type == :ul
-      list.children.map { parse_list_item(_1) }
-    end
-    node
-  end
-
-  def resolve_tag(name)
-    names = TagName.where(language_code: 'ja', name:).to_a
-    tag_ids = names.filter_map(&:tag_id).uniq
-    invalid!("Tag #{ name.inspect } を解決できません．") if tag_ids.empty?
-    invalid!("Tag 名 #{ name.inspect } が曖昧です．") if tag_ids.many?
-
-    tag_ids.first
-  end
-
-  def build_members(nodes)
-    references = []
-    visit = lambda do |items|
-      items.each do |node|
-        references << node.slice('tag_id', 'tag_group_id') if
-            node.key?('tag_id') || node.key?('tag_group_id')
-        visit.call(node.fetch('children'))
-      end
-    end
-    visit.call(nodes)
-    references.uniq
-  end
-
-  def inline_text(node)
-    if node.attr.any?
-      invalid!("未対応のインライン構文 #{ node.type.inspect } です．")
-    end
-
-    case node.type
-    when :text
-      node.value.to_s
-    when :p, :header
-      node.children.map { inline_text(_1) }.join
-    else
-      invalid!("未対応のインライン構文 #{ node.type.inspect } です．")
-    end
-  end
-
-  def inline_markdown(node)
-    case node.type
-    when :text
-      node.value.to_s
-    when :codespan
-      text = node.value.to_s
-      longest = text.scan(/`+/).map(&:length).max || 0
-      delimiter = '`' * (longest + 1)
-      padded = text.start_with?('`', ' ') || text.end_with?('`', ' ')
-      content = padded ? " #{ text } " : text
-      "#{ delimiter }#{ content }#{ delimiter }"
-    when :softbreak
-      "\n"
-    when :br
-      "  \n"
-    when :p
-      node.children.map { inline_markdown(_1) }.join
-    when :a
-      href = node.attr.fetch('href')
-      label = node.children.map { inline_markdown(_1) }.join
-      title = node.attr['title']&.gsub('"', '\\"')
-      suffix = title ? " \"#{ title }\"" : ''
-      "[#{ label }](#{ href }#{ suffix })"
-    when :em
-      "*#{ node.children.map { inline_markdown(_1) }.join }*"
-    when :strong
-      "**#{ node.children.map { inline_markdown(_1) }.join }**"
-    else
-      invalid!("未対応の説明文構文 #{ node.type.inspect } です．")
-    end
-  end
-
-  def invalid! message
-    raise InvalidDocument, message
-  end
-end

backend/app/services/tag_group_markdown_renderer.rb

@@ -1,118 +0,0 @@
-class TagGroupMarkdownRenderer
-  class UnsupportedStructure < StandardError
-    ;
-  end
-
-  def self.render group
-    new(group).render
-  end
-
-  def initialize group
-    @group = group
-  end
-
-  def render
-    placements = @group.fetch('placements')
-    validate_membership!(placements)
-    blocks = []
-    if @group['description'].present?
-      blocks << clean_text(@group['description'])
-    end
-
-    sections = placements.select { _1.key?('section_name') }
-    if sections.any? && sections.size != placements.size
-      raise UnsupportedStructure,
-          '最上位の見出し Section と Placement の混在は Markdown にできません．'
-    end
-
-    if placements.all? { _1.key?('section_name') }
-      blocks.concat(placements.map { render_heading(_1, 2) })
-    else
-      blocks << render_list(placements, 0)
-    end
-
-    blocks.compact.reject(&:empty?).join("\n").sub(/\n+\z/, '')
-  end
-
-  private
-
-  def validate_membership! placements
-    placed = placement_members(placements).uniq.sort
-    members = @group.fetch('members').map { |member|
-      if member['tag']
-        ['tag', member.fetch('tag').fetch('id')]
-      else
-        ['tag_group', member.fetch('tag_group').fetch('id')]
-      end
-    }.uniq.sort
-    missing = members - placed
-    if missing.any?
-      raise UnsupportedStructure, '掲載位置のない membership は Markdown にできません．'
-    end
-  end
-
-  def placement_members nodes
-    nodes.flat_map do |node|
-      own = if node['tag']
-        [['tag', node.fetch('tag').fetch('id')]]
-      elsif node['tag_group']
-        [['tag_group', node.fetch('tag_group').fetch('id')]]
-      else
-        []
-      end
-      own + placement_members(node.fetch('children'))
-    end
-  end
-
-  def render_heading section, level
-    header = "#{ '#' * level } #{ clean_text(section.fetch('section_name')) }"
-    blocks = [header]
-    blocks << clean_text(section['description']) if section['description'].present?
-    children = section.fetch('children')
-    section_indexes = children.each_index.select { |index| children[index].key?('section_name') }
-    if section_indexes.any?
-      first_section = section_indexes.first
-      if children[first_section..].any? { !_1.key?('section_name') }
-        raise UnsupportedStructure,
-            '見出し Section と兄弟 Placement の交互配置は Markdown にできません．'
-      end
-      list_nodes = children[0...first_section]
-      blocks << render_list(list_nodes, 0) if list_nodes.any?
-      blocks.concat(children[first_section..].map { render_heading(_1, level + 1) })
-    elsif children.any?
-      blocks << render_list(children, 0)
-    end
-    blocks.join("\n")
-  end
-
-  def render_list nodes, depth
-    nodes.map do |node|
-      indent = '  ' * depth
-      if node.key?('section_name')
-        raise UnsupportedStructure,
-            'リスト内 Section の説明文は Markdown にできません．' if node['description'].present?
-
-        children = node.fetch('children')
-        head = "#{ indent }- #{ clean_text(node.fetch('section_name')) }:"
-        tail = render_list(children, depth + 1) if children.any?
-        [head, tail].compact.join("\n")
-      else
-        label = if node['tag']
-          node.fetch('tag').fetch('name')
-        else
-          "#{ TagGroupRepr::PREFIX }#{ node.fetch('tag_group').fetch('name') }"
-        end
-        raise UnsupportedStructure, '名称のない Placement は Markdown にできません．' if label.blank?
-
-        head = "#{ indent }- #{ clean_text(label) }"
-        children = node.fetch('children')
-        tail = render_list(children, depth + 1) if children.any?
-        [head, tail].compact.join("\n")
-      end
-    end.join("\n")
-  end
-
-  def clean_text value
-    value.to_s.gsub(/\r\n?/, "\n").lines.map(&:rstrip).join("\n").strip
-  end
-end

backend/app/services/tag_group_operation.rb

@@ -1,410 +0,0 @@
-class TagGroupOperation
-  MAX_PLACEMENT_DEPTH = 5
-  PREFIX = TagGroupRepr::PREFIX
-
-  def self.create!(name:, description:, members:, placements:, actor:,
-                   require_compatibility: false, compatibility_body: nil)
-    group, sync_issue = ApplicationRecord.transaction do
-      group = TagGroup.new(version_no: 1, created_by_user: actor,
-                           updated_by_user: actor)
-      attributes = prepare!(group:, name:, description:, members:, placements:)
-      group.assign_attributes(name: attributes.fetch(:name),
-                              description: attributes.fetch(:description))
-      group.save!
-      persist_structure!(group:, attributes:, actor:)
-      persist_version!(group:, attributes:, actor:, event_type: 'create')
-      issue = sync_compatibility!(group:, actor:, old_name: nil,
-                                  require_compatibility:, compatibility_body:)
-      [group, issue]
-    end
-    report_sync_issue(group, actor, sync_issue)
-    group
-  end
-
-  def self.update!(group:, name:, description:, members:, placements:, actor:,
-                   require_compatibility: false, compatibility_body: nil)
-    group, sync_issue = ApplicationRecord.transaction do
-      group.lock!
-      old_name = group.name
-      attributes = prepare!(group:, name:, description:, members:, placements:)
-      next [group, nil] if unchanged?(group, attributes)
-
-      group.update!(name: attributes.fetch(:name),
-                    description: attributes.fetch(:description),
-                    version_no: group.version_no + 1,
-                    updated_by_user: actor)
-      persist_structure!(group:, attributes:, actor:)
-      persist_version!(group:, attributes:, actor:, event_type: 'update')
-      issue = sync_compatibility!(group:, actor:, old_name:,
-                                  require_compatibility:, compatibility_body:)
-      [group, issue]
-    end
-    report_sync_issue(group, actor, sync_issue)
-    group
-  end
-
-  def self.prepare!(group:, name:, description:, members:, placements:)
-    record = group
-    normalized_name = name.to_s.strip
-    invalid!(record, :name, 'グループ名は必須です．') if normalized_name.blank?
-    if normalized_name.length > 255
-      invalid!(record, :name, 'グループ名は 255 文字以内で入力してください．')
-    end
-    invalid!(record, :description, '説明文は文字列で入力してください．') unless
-        description.nil? || description.is_a?(String)
-
-    record.name = normalized_name
-    record.description = description
-    unless record.valid?
-      raise ActiveRecord::RecordInvalid, record
-    end
-
-    member_rows = normalize_members(record, members)
-    placement_tree = normalize_placements(record, placements)
-    validate_references!(record, member_rows, placement_tree)
-    validate_containment!(record, member_rows)
-    { name: normalized_name, description:, members: member_rows,
-      placements: placement_tree }
-  end
-  private_class_method :prepare!
-
-  def self.unchanged?(group, attributes)
-    unless (group.name_in_database == attributes.fetch(:name) &&
-            group.description_in_database == attributes.fetch(:description))
-      return false
-    end
-
-    members = TagGroupTag.where(tag_group_id: group.id).pluck(:tag_id)
-        .map { { 'tag_id' => _1 } }
-    members.concat(TagGroupGroup.where(tag_group_id: group.id)
-        .pluck(:child_tag_group_id).map { { 'tag_group_id' => _1 } })
-    requested_members = attributes.fetch(:members).map do |member|
-      member.except('version_no')
-    end
-    return false unless members.to_set == requested_members.to_set
-
-    rows = TagGroupPlacement.where(tag_group_id: group.id).order(:position)
-        .group_by(&:parent_position)
-    build = lambda do |parent_position|
-      rows.fetch(parent_position, []).map do |row|
-        node = if row.tag_id
-          { 'tag_id' => row.tag_id }
-        elsif row.child_tag_group_id
-          { 'tag_group_id' => row.child_tag_group_id }
-        else
-          { 'section_name' => row.section_name, 'description' => row.description }
-        end
-        node.merge('children' => build.call(row.position))
-      end
-    end
-    build.call(nil) == comparable_placements(attributes.fetch(:placements))
-  end
-  private_class_method :unchanged?
-
-  def self.comparable_placements(nodes)
-    nodes.map do |node|
-      result = node.dup
-      result['description'] = node['description'] if node.key?('section_name')
-      result['children'] = comparable_placements(node.fetch('children'))
-      result
-    end
-  end
-  private_class_method :comparable_placements
-
-  def self.normalize_members(record, members)
-    invalid!(record, :members, 'members は配列で指定してください．') unless members.is_a?(Array)
-
-    result = members.map do |member|
-      member = stringify_keys(member)
-      unless member.is_a?(Hash) && member.keys.one? &&
-             (member.key?('tag_id') || member.key?('tag_group_id'))
-        invalid!(record, :members, '各 member は tag_id または tag_group_id を一つ指定してください．')
-      end
-      key = member.keys.first
-      id = integer_id(record, member.fetch(key), :members)
-      { key => id }
-    end
-    invalid!(record, :members, 'membership に重複があります．') unless result.uniq == result
-    result
-  end
-  private_class_method :normalize_members
-
-  def self.normalize_placements(record, placements)
-    invalid!(record, :placements, 'placements は配列で指定してください．') unless
-        placements.is_a?(Array)
-
-    normalize_placement_nodes(record, placements, 1)
-  end
-  private_class_method :normalize_placements
-
-  def self.normalize_placement_nodes(record, nodes, depth)
-    if depth > MAX_PLACEMENT_DEPTH && nodes.any?
-      invalid!(record, :placements, '配置の深さは 5 階層までです．')
-    end
-
-    nodes.map do |raw_node|
-      node = stringify_keys(raw_node)
-      unless node.is_a?(Hash) && node.key?('children')
-        invalid!(record, :placements, '各 Placement に children 配列が必要です．')
-      end
-      children = node.delete('children')
-      unless children.is_a?(Array)
-        invalid!(record, :placements, 'children は配列で指定してください．')
-      end
-
-      kinds = ['tag_id', 'tag_group_id', 'section_name'].select { node.key?(_1) }
-      invalid!(record, :placements, 'Placement の種類を一つ指定してください．') unless
-          kinds.one?
-      kind = kinds.first
-      allowed = [kind, 'description']
-      invalid!(record, :placements, '不明な Placement 項目があります．') unless
-          (node.keys - allowed).empty?
-
-      case kind
-      when 'tag_id', 'tag_group_id'
-        node[kind] = integer_id(record, node.fetch(kind), :placements)
-        if node['description'].present?
-          invalid!(record, :placements, 'Tag / Tag Group Placement に説明文は指定できません．')
-        end
-        node.delete('description')
-      when 'section_name'
-        section_name = node.fetch(kind)
-        unless section_name.is_a?(String) && section_name.strip.present? &&
-               section_name.length <= 255
-          invalid!(record, :placements, 'Section 名は 1〜255 文字で入力してください．')
-        end
-        node[kind] = section_name.strip
-        unless node['description'].nil? || node['description'].is_a?(String)
-          invalid!(record, :placements, 'Section の説明文は文字列で入力してください．')
-        end
-      end
-
-      node['children'] = normalize_placement_nodes(record, children, depth + 1)
-      node
-    end
-  end
-  private_class_method :normalize_placement_nodes
-
-  def self.validate_references!(record, members, placements)
-    membership = members.to_set
-    placed = placement_references(placements).uniq
-    missing = placed - membership.to_a
-    invalid!(record, :placements, 'Placement の対象は membership に含めてください．') if
-        missing.any?
-
-    tag_ids = members.filter_map { _1['tag_id'] }
-    group_ids = members.filter_map { _1['tag_group_id'] }
-    tags = Tag.where(id: tag_ids).index_by(&:id)
-    groups = TagGroup.where(id: group_ids).index_by(&:id)
-    invalid!(record, :members, '存在しない Tag が含まれています．') if
-        tags.size != tag_ids.uniq.size
-    invalid!(record, :members, '存在しない Tag Group が含まれています．') if
-        groups.size != group_ids.uniq.size
-
-    tag_versions = TagVersion.where(tag_id: tag_ids).pluck(:tag_id, :version_no).to_set
-    group_versions = TagGroupVersion.where(tag_group_id: group_ids)
-        .pluck(:tag_group_id, :version_no).to_set
-    tag_names = TagName.where(tag_id: tag_ids, language_code: 'ja', primary_flg: true)
-        .pluck(:tag_id).uniq
-
-    members.each do |member|
-      if member.key?('tag_id')
-        id = member.fetch('tag_id')
-        invalid!(record, :members, "Tag ##{ id } に日本語の正規名がありません．") unless
-            tag_names.include?(id)
-        version_no = tags.fetch(id).version_no
-        unless tag_versions.include?([id, version_no])
-          invalid!(record, :members, "Tag ##{ id } の Version がありません．")
-        end
-        member['version_no'] = version_no
-      else
-        id = member.fetch('tag_group_id')
-        version_no = groups.fetch(id).version_no
-        unless group_versions.include?([id, version_no])
-          invalid!(record, :members, "Tag Group ##{ id } の Version がありません．")
-        end
-        member['version_no'] = version_no
-      end
-    end
-  end
-  private_class_method :validate_references!
-
-  def self.validate_containment!(record, members)
-    target_id = record.id
-    return unless target_id
-
-    children = members.filter_map { _1['tag_group_id'] }
-    edges = TagGroupGroup.pluck(:tag_group_id, :child_tag_group_id)
-        .group_by(&:first).transform_values { _1.map(&:last) }
-    edges[target_id] = children
-    visiting = Set.new
-    visited = Set.new
-    visit = lambda do |group_id|
-      invalid!(record, :members, 'Tag Group の循環包含はできません．') if
-          group_id == target_id && visiting.include?(group_id)
-      return if visited.include?(group_id)
-
-      visiting.add(group_id)
-      edges.fetch(group_id, []).each do |child_id|
-        invalid!(record, :members, 'Tag Group の循環包含はできません．') if
-            child_id == target_id
-        visit.call(child_id)
-      end
-      visiting.delete(group_id)
-      visited.add(group_id)
-    end
-    children.each { visit.call(_1) }
-  end
-  private_class_method :validate_containment!
-
-  def self.persist_structure!(group:, attributes:, actor:)
-    tag_members = TagGroupTag.where(tag_group_id: group.id).index_by(&:tag_id)
-    group_members = TagGroupGroup.where(tag_group_id: group.id).index_by(&:child_tag_group_id)
-    attributes.fetch(:members).each do |member|
-      if member.key?('tag_id')
-        next if tag_members.delete(member.fetch('tag_id'))
-
-        TagGroupTag.create!(tag_group_id: group.id, tag_id: member.fetch('tag_id'),
-                            created_by_user: actor)
-      else
-        next if group_members.delete(member.fetch('tag_group_id'))
-
-        TagGroupGroup.create!(tag_group_id: group.id,
-                              child_tag_group_id: member.fetch('tag_group_id'),
-                              created_by_user: actor)
-      end
-    end
-    existing = TagGroupPlacement.where(tag_group_id: group.id).index_by(&:position)
-    persist_placements!(group:, nodes: attributes.fetch(:placements), actor:, existing:)
-    existing.values.sort_by(&:position).reverse_each(&:delete)
-    tag_members.each_value(&:delete)
-    group_members.each_value(&:delete)
-  end
-  private_class_method :persist_structure!
-
-  def self.persist_placements!(group:, nodes:, actor:, existing:, parent_position: nil,
-                               next_position: [0])
-    nodes.each do |node|
-      next_position[0] += 1
-      position = next_position[0]
-      row = existing.delete(position) || TagGroupPlacement.new(
-          tag_group_id: group.id, position:, created_by_user: actor)
-      row.assign_attributes(
-          parent_position:,
-          section_name: node['section_name'], description: node['description'],
-          tag_id: node['tag_id'], child_tag_group_id: node['tag_group_id'])
-      if row.new_record? || row.changed?
-        row.updated_by_user = actor
-        row.save!
-      end
-      persist_placements!(group:, nodes: node.fetch('children'), actor:, existing:,
-                          parent_position: position, next_position:)
-    end
-  end
-  private_class_method :persist_placements!
-
-  def self.persist_version!(group:, attributes:, actor:, event_type:)
-    TagGroupVersion.create!(tag_group: group, version_no: group.version_no,
-                            event_type:, name: group.name,
-                            description: group.description,
-                            members: attributes.fetch(:members),
-                            placements: attributes.fetch(:placements),
-                            created_by_user: actor)
-  end
-  private_class_method :persist_version!
-
-  def self.sync_compatibility!(group:, actor:, old_name:,
-                               require_compatibility:, compatibility_body:)
-    representation = TagGroupRepr.one(group)
-    body = begin
-      TagGroupMarkdownRenderer.render(representation)
-    rescue TagGroupMarkdownRenderer::UnsupportedStructure => error
-      if compatibility_body.present?
-        compatibility_body
-      elsif require_compatibility
-        invalid!(group, :base, error.message)
-      else
-        return error.message
-      end
-    end
-    invalid!(group, :base, '本文は必須です．') if body.blank?
-
-    title = "#{ PREFIX }#{ group.name }"
-    old_title = old_name && "#{ PREFIX }#{ old_name }"
-    page = if old_title
-      WikiPage.joins(:tag_name).find_by(tag_names: { name: old_title })
-    else
-      nil
-    end
-    page ||= WikiPage.joins(:tag_name).find_by(tag_names: { name: title })
-
-    if page
-      tag_name = page.tag_name
-      tag_name.update!(name: title) if tag_name.name != title
-      Wiki::Commit.legacy_content!(page:, body:, created_user: actor, message: nil,
-                                   base_revision_id: nil)
-    else
-      tag_name = TagName.find_or_initialize_by(language_code: 'ja', name: title)
-      tag_name.script_code = 'Jpan'
-      tag_name.primary_flg = true
-      tag_name.auto_generated = false
-      tag_name.save!
-      Wiki::Commit.create_legacy_content!(tag_name:, body:, created_by_user: actor)
-    end
-    nil
-  end
-  private_class_method :sync_compatibility!
-
-  def self.report_sync_issue(group, actor, reason)
-    return unless reason
-
-    payload = { status: 'unsupported_structure', tag_group_id: group.id,
-                version_no: group.version_no, user_id: actor&.id, reason: }
-    Rails.logger.warn("tag_group_wiki_sync_skipped #{ payload.to_json }")
-  end
-  private_class_method :report_sync_issue
-
-  def self.placement_references(nodes)
-    nodes.flat_map do |node|
-      own = if node.key?('tag_id')
-        [{ 'tag_id' => node.fetch('tag_id') }]
-      elsif node.key?('tag_group_id')
-        [{ 'tag_group_id' => node.fetch('tag_group_id') }]
-      else
-        []
-      end
-      own + placement_references(node.fetch('children'))
-    end
-  end
-  private_class_method :placement_references
-
-  def self.stringify_keys(value)
-    case value
-    when ActionController::Parameters
-      value.to_unsafe_h.deep_stringify_keys
-    when Hash
-      value.deep_stringify_keys
-    else
-      value
-    end
-  end
-  private_class_method :stringify_keys
-
-  def self.integer_id(record, value, attribute)
-    integer = if value.is_a?(Integer)
-      value
-    elsif value.is_a?(String) && value.match?(/\A[0-9]+\z/)
-      value.to_i
-    end
-    invalid!(record, attribute, 'ID は正の整数で指定してください．') unless integer
-    invalid!(record, attribute, 'ID は正の整数で指定してください．') unless integer.positive?
-    integer
-  end
-  private_class_method :integer_id
-
-  def self.invalid!(record, attribute, message)
-    record.errors.add(attribute, message)
-    raise ActiveRecord::RecordInvalid, record
-  end
-  private_class_method :invalid!
-end

backend/app/services/tag_version_recorder.rb

@@ -1,5 +1,5 @@
 class TagVersionRecorder < VersionRecorder
-  def self.record! tag:, event_type:, created_by_user:, **_options
+  def self.record! tag:, event_type:, created_by_user:
     new(tag:, event_type:, created_by_user:).record!
   end
 
@@ -14,29 +14,10 @@ class TagVersionRecorder < VersionRecorder
   def record_key = :tag
 
   def snapshot_attributes
-    names = snapshot_names
+    { name: @record.name,
-    compatibility_names = names.fetch('ja')
-
-    { name: compatibility_names.fetch('name'),
       category: @record.category,
       deprecated_at: @record.deprecated_at,
-      aliases: compatibility_names.fetch('aliases').map { _1.fetch('name') }.join(' '),
+      aliases: @record.snapshot_aliases.join(' '),
-      names:,
       parent_tag_ids: @record.snapshot_parent_tag_ids.join(' ') }
   end
-
-  def snapshot_names
-    @record.tag_names.order(:language_code, :name).group_by(&:language_code)
-        .transform_values do |tag_names|
-      primary = tag_names.find(&:primary?)
-      aliases = tag_names.reject(&:primary?).sort_by(&:name).map { |tag_name|
-        { 'name' => tag_name.name, 'script_code' => tag_name.script_code }
-      }
-
-      { 'name' => primary.name,
-        'script_code' => primary.script_code,
-        'auto_generated' => primary.auto_generated,
-        'aliases' => aliases }
-    end
-  end
 end

backend/app/services/tag_versioning.rb

@@ -1,22 +1,38 @@
 class TagVersioning
-  def self.record! tag, event_type:, created_by_user:, language_code: 'ja'
+  def self.record! tag, event_type:, created_by_user:
-    TagVersionRecorder.record!(tag:, event_type:, created_by_user:, language_code:)
+    if tag.nico?
+      NicoTagVersionRecorder.record!(tag:, event_type:, created_by_user:)
+    else
+      TagVersionRecorder.record!(tag:, event_type:, created_by_user:)
+    end
   end
 
-  def self.ensure_snapshot! tag, created_by_user:, language_code: 'ja'
+  def self.ensure_snapshot! tag, created_by_user:
+    if tag.nico?
+      return if tag.nico_tag_versions.exists?
+
+      NicoTagVersionRecorder.record!(tag:, event_type: :create, created_by_user:)
+    else
       return if tag.tag_versions.exists?
 
-    TagVersionRecorder.record!(tag:, event_type: :create, created_by_user:, language_code:)
+      TagVersionRecorder.record!(tag:, event_type: :create, created_by_user:)
+    end
   end
 
-  def self.record_tag_snapshot! tag, created_by_user:, language_code: 'ja'
+  def self.record_tag_snapshot! tag, created_by_user:
-    event_type = tag.tag_versions.exists? ? :update : :create
+    event_type =
-    record!(tag, event_type:, created_by_user:, language_code:)
+        if tag.nico?
+          tag.nico_tag_versions.exists? ? :update : :create
+        else
+          tag.tag_versions.exists? ? :update : :create
         end
 
-  def self.record_tag_snapshots! tags, created_by_user:, language_code: 'ja'
+    record!(tag, event_type:, created_by_user:)
+  end
+
+  def self.record_tag_snapshots! tags, created_by_user:
     tags.each do |tag|
-      record_tag_snapshot!(tag, created_by_user:, language_code:)
+      record_tag_snapshot!(tag, created_by_user:)
     end
   end
 end

backend/app/services/theatre_post_selector.rb

@@ -41,7 +41,7 @@ class TheatrePostSelector
   def weighted_candidates
     @weighted_candidates ||= begin
       penalties = tag_penalties
-      posts = eligible_posts.includes(tags: :tag_names).to_a
+      posts = eligible_posts.includes(tags: :tag_name).to_a
 
       posts.map do |post|
         post_tags = post.tags.to_a
@@ -82,7 +82,7 @@ class TheatrePostSelector
   def tag_penalty_json
     return [] if tag_penalties.empty?
 
-    tags = Tag.where(id: tag_penalties.keys).includes(:tag_names).index_by(&:id)
+    tags = Tag.where(id: tag_penalties.keys).includes(:tag_name).index_by(&:id)
 
     tag_penalties
       .map { |tag_id, penalty|
@@ -113,7 +113,7 @@ class TheatrePostSelector
 
   def light_tag_json tag
     { id: tag.id,
-      name: tag.name('ja'),
+      name: tag.name,
       category: tag.category }
   end
 end

backend/app/services/version_recorder.rb

@@ -47,14 +47,10 @@ class VersionRecorder
   end
 
   def update_record_version_no! version_no
-    return unless tracks_version_no_on_record?
-
     @record.update_columns(version_no:)
     @record.version_no = version_no
   end
 
-  def tracks_version_no_on_record? = true
-
   def validate_version_sequence! latest
     if !(latest) && @event_type != 'create'
       raise "#{ version_class.name } first event must be create"
@@ -64,7 +60,7 @@ class VersionRecorder
       raise "#{ version_class.name } create event already exists"
     end
 
-    return if !(latest) || !(tracks_version_no_on_record?)
+    return unless latest
 
     if @record.version_no != latest.version_no
       raise ("#{ record_class.name }##{ @record.id } version_no is #{ @record.version_no }, " +

backend/app/services/wiki/commit.rb

@@ -8,15 +8,6 @@ module Wiki
     end
 
     def self.create_content! tag_name:, body:, created_by_user:, message: nil
-      if tag_name.tag && tag_name.language_code == 'ja'
-        return TagDescriptionOperation.create!(
-            tag: tag_name.tag, body:, created_by_user:, message:)
-      end
-
-      create_legacy_content!(tag_name:, body:, created_by_user:, message:)
-    end
-
-    def self.create_legacy_content! tag_name:, body:, created_by_user:, message: nil
       normalised = normalise_body(body)
 
       page = WikiPage.new(tag_name:,
@@ -42,18 +33,6 @@ module Wiki
     end
 
     def self.content! page:, body:, created_user:, message: nil, base_revision_id: nil
-      description = TagDescription.find_by(id: page.id)
-      if description
-        return TagDescriptionOperation.update!(
-            tag: description.tag, body:, updated_by_user: created_user,
-            message:, base_revision_id:)
-      end
-
-      legacy_content!(page:, body:, created_user:, message:, base_revision_id:)
-    end
-
-    def self.legacy_content! page:, body:, created_user:, message: nil,
-                             base_revision_id: nil
       new(page:, created_user:).content!(body:, message:, base_revision_id:)
     end
 
@@ -78,6 +57,9 @@ module Wiki
       line_shas = lines.map { |line| Digest::SHA256.hexdigest(line) }
       tree_sha = Digest::SHA256.hexdigest(line_shas.join(','))
 
+      line_id_by_sha = upsert_lines!(lines, line_shas)
+      line_ids = line_shas.map { |sha| line_id_by_sha.fetch(sha) }
+
       ActiveRecord::Base.transaction do
         @page.lock!
 
@@ -90,8 +72,6 @@ module Wiki
           end
         end
 
-        line_id_by_sha = upsert_lines!(lines, line_shas)
-        line_ids = line_shas.map { |sha| line_id_by_sha.fetch(sha) }
         @page.update!(body: normalised)
 
         WikiVersionRecorder.record!(
@@ -114,6 +94,7 @@ module Wiki
           { wiki_revision_id: rev.id, wiki_line_id: line_id, position: pos }
         end
         WikiRevisionLine.insert_all!(rows) if rows.any?
+
         rev
       end
     end

backend/app/services/wiki/compatibility_writer.rb

@@ -1,33 +0,0 @@
-module Wiki
-  class CompatibilityWriter
-    def self.create! tag_name:, body:, created_by_user:, message: nil
-      Commit.create_legacy_content!(
-          tag_name:, body:, created_by_user:, message:)
-    end
-
-    def self.update! page:, body:, updated_by_user:, message: nil,
-                     base_revision_id: nil
-      normalised = Commit.normalise_body(body)
-      if normalised.blank?
-        return Commit.legacy_content!(
-            page:, body: normalised, created_user: updated_by_user, message:,
-            base_revision_id:)
-      end
-
-      if base_revision_id.present?
-        current_id = page.wiki_revisions.maximum(:id)
-        if current_id && current_id != base_revision_id.to_i
-          raise Commit::Conflict,
-              "競合が発生してゐます" +
-              "（現在の Id.：#{ current_id }，ベース Id.：#{ base_revision_id }）．"
-        end
-      end
-
-      return if Commit.normalise_body(page.body) == normalised
-
-      Commit.legacy_content!(
-          page:, body: normalised, created_user: updated_by_user, message:,
-          base_revision_id:)
-    end
-  end
-end

backend/app/services/youtube/sync.rb

@@ -103,7 +103,7 @@ module Youtube
     end
 
     def sync_post_tags! post, desired_tag_ids, current_tag_ids: nil
-      current_tag_ids ||= PostTag.where(post_id: post.id).pluck(:tag_id).to_set
+      current_tag_ids ||= PostTag.kept.where(post_id: post.id).pluck(:tag_id).to_set
       desired_tag_ids = desired_tag_ids.compact.to_set
 
       to_add = desired_tag_ids - current_tag_ids
@@ -117,8 +117,8 @@ module Youtube
         end
       end
 
-      PostTag.where(post_id: post.id, tag_id: to_remove.to_a).find_each do |pt|
+      PostTag.where(post_id: post.id, tag_id: to_remove.to_a).kept.find_each do |pt|
-        pt.destroy!
+        pt.discard_by!(nil)
       end
     end
 

backend/config/routes.rb

@@ -1,7 +1,5 @@
 Rails.application.routes.draw do
-  resources :tag_groups, only: [:index, :show, :create, :update]
+  resources :nico_tags, path: 'tags/nico', only: [:index, :update]
-
-  resources :nico_tags, path: 'tags/nico', only: [:index, :show, :update]
 
   scope 'tags/:parent_id/children', controller: :tag_children do
     post ':child_id', action: :create
@@ -16,7 +14,6 @@ Rails.application.routes.draw do
 
       scope :name do
         get ':name/deerjikists', action: :deerjikists_by_name
-        get ':name/description', to: 'tag_descriptions#show_by_title'
         get ':name/materials', action: :materials_by_name
         get ':name', action: :show_by_name
       end
@@ -28,9 +25,6 @@ Rails.application.routes.draw do
 
       get :deerjikists
       put :deerjikists, action: :update_deerjikists
-
-      get :description, to: 'tag_descriptions#show'
-      put :description, to: 'tag_descriptions#update'
     end
   end
 
@@ -41,7 +35,7 @@ Rails.application.routes.draw do
 
   resources :wiki_pages, path: 'wiki', only: [:index, :show, :create, :update] do
     collection do
-      get :search, action: :index
+      get :search
       get :changes
 
       scope :title do
@@ -61,6 +55,7 @@ Rails.application.routes.draw do
       get :metadata
       post :bulk
       get :random
+      get :changes
       get :versions, to: 'post_versions#index'
     end
 

backend/db/migrate/20260921000000_delete_inactive_records_from_post_tags.rb

@@ -1,53 +0,0 @@
-class DeleteInactiveRecordsFromPostTags < ActiveRecord::Migration[8.0]
-  def up
-    execute <<~SQL
-      DELETE
-      FROM
-        post_tags
-      WHERE
-        discarded_at IS NOT NULL
-    SQL
-
-    remove_index :post_tags, [:tag_id, :discarded_at]
-    remove_index :post_tags, [:post_id, :discarded_at]
-    remove_index :post_tags, name: 'idx_post_tags_active_unique'
-    remove_index :post_tags, :discarded_at
-
-    remove_foreign_key :post_tags, column: :deleted_user_id
-    remove_index :post_tags, :deleted_user_id
-
-    remove_column :post_tags, :active_unique_key
-    remove_column :post_tags, :is_active
-    remove_column :post_tags, :discarded_at
-    remove_column :post_tags, :deleted_user_id
-    remove_column :post_tags, :updated_at
-
-    execute <<~SQL
-      ALTER TABLE
-        post_tags
-      MODIFY COLUMN
-        id BIGINT NOT NULL
-    SQL
-
-    execute <<~SQL
-      ALTER TABLE
-        post_tags
-      DROP PRIMARY KEY
-    SQL
-
-    remove_column :post_tags, :id
-
-    execute <<~SQL
-      ALTER TABLE
-        post_tags
-      ADD PRIMARY KEY
-        (post_id, tag_id)
-    SQL
-
-    remove_index :post_tags, :post_id
-  end
-
-  def down
-    raise ActiveRecord::IrreversibleMigration, '戻せません．'
-  end
-end

backend/db/migrate/20260921010000_add_foreign_key_on_post_id_and_tag_id_in_post_tag_sections.rb

@@ -1,11 +0,0 @@
-class AddForeignKeyOnPostIdAndTagIdInPostTagSections < ActiveRecord::Migration[8.0]
-  def change
-    remove_foreign_key :post_tag_sections, :posts, column: :post_id
-    remove_foreign_key :post_tag_sections, :tags, column: :tag_id
-
-    add_foreign_key :post_tag_sections, :post_tags,
-                    column: [:post_id, :tag_id],
-                    primary_key: [:post_id, :tag_id],
-                    on_delete: :cascade
-  end
-end

backend/db/migrate/20260921020000_delete_discarded_records_from_tags.rb

@@ -1,46 +0,0 @@
-class DeleteDiscardedRecordsFromTags < ActiveRecord::Migration[8.0]
-  def up
-    remove_foreign_key :tag_versions, :tags, column: :tag_id
-    remove_foreign_key :nico_tag_versions, :tags, column: :tag_id
-    remove_foreign_key :material_versions, :tags, column: :tag_id
-
-    execute <<~SQL
-      DELETE
-        ntr
-      FROM
-        nico_tag_relations ntr
-        INNER JOIN
-          tags t
-          ON
-            t.discarded_at IS NOT NULL
-            AND t.id IN (ntr.tag_id, ntr.nico_tag_id)
-    SQL
-
-    execute <<~SQL
-      DELETE
-        ti
-      FROM
-        tag_implications ti
-        INNER JOIN
-          tags t
-          ON
-            t.discarded_at IS NOT NULL
-            AND t.id IN (ti.tag_id, ti.parent_tag_id)
-    SQL
-
-    execute <<~SQL
-      DELETE
-      FROM
-        tags
-      WHERE
-        discarded_at IS NOT NULL
-    SQL
-
-    remove_index :tags, :discarded_at
-    remove_column :tags, :discarded_at
-  end
-
-  def down
-    raise ActiveRecord::IrreversibleMigration, '戻せません．'
-  end
-end

backend/db/migrate/20260921030000_delete_discarded_records_from_tag_names.rb

@@ -1,18 +0,0 @@
-class DeleteDiscardedRecordsFromTagNames < ActiveRecord::Migration[8.0]
-  def up
-    execute <<~SQL
-      DELETE
-      FROM
-        tag_names
-      WHERE
-        discarded_at IS NOT NULL
-    SQL
-
-    remove_index :tag_names, :discarded_at
-    remove_column :tag_names, :discarded_at
-  end
-
-  def down
-    raise ActiveRecord::IrreversibleMigration, '戻せません．'
-  end
-end

backend/db/migrate/20260921040000_create_external_tags.rb

@@ -1,54 +0,0 @@
-class CreateExternalTags < ActiveRecord::Migration[8.0]
-  def up
-    create_table :external_tags do |t|
-      t.string :platform, limit: 16, null: false
-      t.string :name, limit: 255, null: false
-      t.integer :post_count, null: false, default: 0
-      t.datetime :created_at, null: false
-
-      t.index [:platform, :name], unique: true
-    end
-
-    execute <<~SQL
-      INSERT INTO
-        external_tags(id, platform, name, post_count, created_at)
-      SELECT
-        t.id
-      , 'nico' AS platform
-      , SUBSTR(tn.name, 6) AS name
-      , t.post_count
-      , t.created_at
-      FROM
-        tags t
-        INNER JOIN
-          tag_names tn
-          ON
-            tn.id = t.tag_name_id
-            AND t.category = 'nico'
-    SQL
-
-    execute <<~SQL
-      INSERT INTO
-        external_tags(id, platform, name, post_count, created_at)
-      SELECT
-        ntv.tag_id
-      , 'nico' AS platform
-      , SUBSTR(ntv.name, 6) AS name
-      , 0 AS post_count
-      , ntv.created_at
-      FROM
-        nico_tag_versions ntv
-        LEFT JOIN
-          external_tags et
-          ON
-            et.id = ntv.tag_id
-      WHERE
-        ntv.version_no = 1
-        AND et.id IS NULL
-    SQL
-  end
-
-  def down
-    drop_table :external_tags
-  end
-end

backend/db/migrate/20260921050000_create_post_external_tags.rb

@@ -1,29 +0,0 @@
-class CreatePostExternalTags < ActiveRecord::Migration[8.0]
-  def up
-    create_table :post_external_tags, primary_key: [:post_id, :external_tag_id] do |t|
-      t.references :post, null: false, index: false, foreign_key: true
-      t.references :external_tag, null: false, foreign_key: true
-      t.datetime :created_at, null: false
-    end
-
-    execute <<~SQL
-      INSERT INTO
-        post_external_tags(post_id, external_tag_id, created_at)
-      SELECT
-        pt.post_id
-      , pt.tag_id AS external_tag_id
-      , pt.created_at
-      FROM
-        post_tags pt
-        INNER JOIN
-          tags t
-          ON
-            pt.tag_id = t.id
-            AND t.category = 'nico'
-    SQL
-  end
-
-  def down
-    drop_table :post_external_tags
-  end
-end

backend/db/migrate/20260921060000_change_foreign_key_on_nico_tag_relations.rb

@@ -1,6 +0,0 @@
-class ChangeForeignKeyOnNicoTagRelations < ActiveRecord::Migration[8.0]
-  def change
-    remove_foreign_key :nico_tag_relations, :tags, column: :nico_tag_id
-    add_foreign_key :nico_tag_relations, :external_tags, column: :nico_tag_id
-  end
-end

backend/db/migrate/20260921230000_migrate_external_tags.rb

@@ -1,199 +0,0 @@
-class MigrateExternalTags < ActiveRecord::Migration[8.0]
-  class MigrationPostVersion < ActiveRecord::Base
-    self.table_name = 'post_versions'
-  end
-
-  def up
-    x = connection.select_value(<<~SQL)
-      SELECT
-        COUNT(0)
-      FROM
-        post_tag_sections pts
-      INNER JOIN
-        tags t
-        ON
-          t.id = pts.tag_id
-      WHERE
-        t.category = 'nico'
-    SQL
-    if x > 0
-      raise "post_tag_sections に #{ x } 件のチンカスがあります!"
-    end
-
-    x = connection.select_value(<<~SQL)
-      SELECT
-        COUNT(0)
-      FROM
-        materials m
-        INNER JOIN
-          tags t
-          ON
-            t.id = m.tag_id
-      WHERE
-        t.category = 'nico'
-    SQL
-    if x > 0
-      raise "materials に #{ x } 件のチンカスがあります!"
-    end
-
-    x = connection.select_value(<<~SQL)
-      SELECT
-        COUNT(0)
-      FROM
-        tag_implications ti
-        INNER JOIN
-          tags t
-          ON
-            t.id = ti.tag_id
-            OR t.id = ti.parent_tag_id
-      WHERE
-        t.category = 'nico'
-    SQL
-    if x > 0
-      raise "tag_implications に #{ x } 件のチンカスがあります!"
-    end
-
-    execute <<~SQL
-      DELETE
-        ts
-      FROM
-        tag_similarities ts
-        INNER JOIN
-          tags t
-          ON
-            t.category = 'nico'
-            AND (t.id = ts.tag_id
-                 OR t.id = ts.target_tag_id)
-    SQL
-
-    execute <<~SQL
-      DELETE
-        tset
-      FROM
-        theatre_skip_event_tags tset
-        INNER JOIN
-          tags t
-          ON
-            t.category = 'nico'
-            AND t.id = tset.tag_id
-    SQL
-
-    remove_check_constraint :post_versions, name: 'chk_post_versions_tags_json_schema'
-
-    say_with_time 'Migrate post_versions.tags_json' do
-      count = 0
-
-      MigrationPostVersion.find_each(batch_size: 500) do |version|
-        tags = version.tags_json.map do |tag|
-          if tag.fetch('category') == 'nico'
-            { 'external_tag_id' => tag.fetch('id') }
-          else
-            { 'tag_id' => tag.fetch('id'),
-              'version_no' => tag.fetch('version_no'),
-              'name' => tag.fetch('name'),
-              'category' => tag.fetch('category'),
-              'sections' => tag.fetch('sections') }
-          end
-        end
-
-        version.update_columns(tags_json: tags)
-        count += 1
-      end
-
-      count
-    end
-
-    add_tags_json_constraint!
-
-    tag_name_ids = connection.select_values(<<~SQL)
-      SELECT
-        tag_name_id
-      FROM
-        tags
-      WHERE
-        category = 'nico'
-    SQL
-
-    connection.transaction do
-      execute <<~SQL
-        DELETE
-          pt
-        FROM
-          post_tags pt
-          INNER JOIN
-            tags t
-            ON
-              t.category = 'nico'
-              AND t.id = pt.tag_id
-      SQL
-
-      execute <<~SQL
-        DELETE
-        FROM
-          tags
-        WHERE
-          category = 'nico'
-      SQL
-
-      unless tag_name_ids.empty?
-        execute <<~SQL
-          DELETE
-          FROM
-            tag_names
-          WHERE
-            id IN (#{ tag_name_ids.join(', ') })
-        SQL
-      end
-    end
-  end
-
-  def down
-    raise ActiveRecord::IrreversibleMigration, '戻せません．'
-  end
-
-  private
-
-  def add_tags_json_constraint!
-    schema = { type: 'array',
-               items: { oneOf: [internal_tag_schema, external_tag_schema] } }
-
-    quoted_schema = connection.quote(JSON.generate(schema))
-
-    add_check_constraint :post_versions,
-                         "JSON_SCHEMA_VALID(#{ quoted_schema }, tags_json)",
-                         name: 'chk_post_versions_tags_json_schema'
-  end
-
-  def internal_tag_schema
-    { type: 'object',
-      properties: { tag_id: { type: 'integer', minimum: 1 },
-                    version_no: { type: 'integer', minimum: 1 },
-                    name: { type: 'string', minLength: 1 },
-                    category: { type: 'string',
-                                enum: ['deerjikist',
-                                       'meme',
-                                       'character',
-                                       'general',
-                                       'material',
-                                       'meta'] },
-                    sections: sections_schema },
-      required: ['tag_id', 'version_no', 'sections'],
-      additionalProperties: false }
-  end
-
-  def external_tag_schema
-    { type: 'object',
-      properties: { external_tag_id: { type: 'integer', minimum: 1 } },
-      required: ['external_tag_id'],
-      additionalProperties: false }
-  end
-
-  def sections_schema
-    { type: 'array',
-      items: { type: 'object',
-               properties: { begin_ms: { type: 'integer', minimum: 0 },
-                             end_ms: { type: ['integer', 'null'], minimum: 0 } },
-               required: ['begin_ms', 'end_ms'],
-               additionalProperties: false } }
-  end
-end

backend/db/migrate/20260922000000_create_languages.rb

@@ -1,20 +0,0 @@
-class CreateLanguages < ActiveRecord::Migration[8.0]
-  def up
-    create_table :languages, id: { type: :string, limit: 16 }, primary_key: :code do |t|
-      t.string :name, null: false
-      t.datetime :deprecated_at, index: true
-      t.datetime :created_at, null: false
-    end
-
-    execute <<~SQL
-      INSERT INTO
-        languages(code, name, created_at)
-      VALUES
-        ('ja', '日本語', #{ connection.quote Time.current })
-    SQL
-  end
-
-  def down
-    drop_table :languages
-  end
-end

backend/db/migrate/20260922010000_create_scripts.rb

@@ -1,23 +0,0 @@
-class CreateScripts < ActiveRecord::Migration[8.0]
-  def up
-    create_table :scripts, id: { type: 'CHAR(4)' }, primary_key: :code do |t|
-      t.string :name, null: false
-      t.datetime :deprecated_at, index: true
-      t.datetime :created_at, null: false
-
-      t.check_constraint "REGEXP_LIKE(code, '^[A-Z][a-z]{3}$', 'c')",
-                         name: 'scripts_code_check'
-    end
-
-    execute <<~SQL
-      INSERT INTO
-        scripts(code, name, created_at)
-      VALUES
-        ('Jpan', '漢字、仮名文字およびラテン文字', #{ connection.quote Time.current })
-    SQL
-  end
-
-  def down
-    drop_table :scripts
-  end
-end

backend/db/migrate/20260922013000_create_regions.rb

@@ -1,25 +0,0 @@
-class CreateRegions < ActiveRecord::Migration[8.0]
-  def up
-    create_table :regions, id: { type: :integer, limit: 2 }, primary_key: :code do |t|
-      t.column :alpha_code, 'CHAR(2)'
-      t.string :name, null: false
-      t.datetime :deprecated_at, index: true
-      t.datetime :created_at, null: false
-
-      t.check_constraint "REGEXP_LIKE(alpha_code, '^[A-Z]{2}$', 'c')",
-                         name: 'regions_alpha_code_check'
-      t.index [:alpha_code], unique: true
-    end
-
-    execute <<~SQL
-      INSERT INTO
-        regions(code, alpha_code, name, created_at)
-      VALUES
-        (392, 'JP', '日本国', #{ connection.quote Time.current })
-    SQL
-  end
-
-  def down
-    drop_table :regions
-  end
-end

backend/db/migrate/20260922020000_create_locales.rb

@@ -1,38 +0,0 @@
-class CreateLocales < ActiveRecord::Migration[8.0]
-  def up
-    create_table :locales, id: { type: :string, limit: 32 }, primary_key: :code do |t|
-      t.string :language_code, limit: 16, null: false, index: true
-      t.column :script_code, 'CHAR(4)', null: false
-      t.integer :region_code, limit: 2, null: false
-      t.string :variants, limit: 255, null: false, default: ''
-      t.string :name, null: false
-      t.datetime :deprecated_at, index: true
-      t.datetime :created_at, null: false
-
-      t.foreign_key :languages, column: :language_code, primary_key: :code
-      t.foreign_key :scripts, column: :script_code, primary_key: :code
-      t.foreign_key :regions, column: :region_code, primary_key: :code
-      t.check_constraint ('REGEXP_LIKE(variants, ' +
-                          "'^(" +
-                          '(([a-z0-9]{5,8}|[0-9][a-z0-9]{3})' +
-                          '(-([a-z0-9]{5,8}|[0-9][a-z0-9]{3}))*' +
-                          '(-x(-[a-z0-9]{1,8})+)?)' +
-                          '|(x(-[a-z0-9]{1,8})+)' +
-                          ")?$', 'c')"),
-                         name: 'locales_variants_check'
-
-      t.index [:language_code, :script_code, :region_code, :variants], unique: true
-    end
-
-    execute <<~SQL
-      INSERT INTO
-        locales(code, language_code, script_code, region_code, name, created_at)
-      VALUES
-        ('ja', 'ja', 'Jpan', 392, '日本語', #{ connection.quote Time.current })
-    SQL
-  end
-
-  def down
-    drop_table :locales
-  end
-end

backend/db/migrate/20260922030000_add_columns_to_tag_names.rb

@@ -1,69 +0,0 @@
-class AddColumnsToTagNames < ActiveRecord::Migration[8.0]
-  def up
-    add_reference :tag_names, :tag, after: :id, foreign_key: true
-    add_column :tag_names, :language_code, :string,
-               limit: 16, null: false, after: :tag_id, default: 'ja'
-    add_column :tag_names, :script_code, 'CHAR(4)',
-               null: false, after: :name, default: 'Jpan'
-    add_column :tag_names, :primary_flg, :boolean,
-               null: false, after: :script_code, default: true
-    add_column :tag_names, :auto_generated, :boolean,
-               null: false, default: false, after: :primary_flg
-
-    add_foreign_key :tag_names, :languages, column: :language_code, primary_key: :code
-    add_foreign_key :tag_names, :scripts, column: :script_code, primary_key: :code
-
-    remove_index :tag_names, :name
-    add_index :tag_names, [:language_code, :name], unique: true
-
-    change_column_default :tag_names, :language_code, from: 'ja', to: nil
-    change_column_default :tag_names, :script_code, from: 'Jpan', to: nil
-
-    execute <<~SQL
-      UPDATE
-        tag_names tn
-        LEFT JOIN
-          tags AS t
-          ON
-            t.tag_name_id = COALESCE(tn.canonical_id, tn.id)
-      SET
-        tn.tag_id = t.id
-      , tn.primary_flg = CASE
-                         WHEN tn.canonical_id IS NULL THEN
-                           1
-                         ELSE
-                           0
-                         END
-    SQL
-
-    change_column_default :tag_names, :primary_flg, from: true, to: nil
-
-    add_column :tag_names, :primary_tag_id, :bigint,
-               as: 'CASE WHEN primary_flg THEN tag_id ELSE NULL END'
-    add_index :tag_names, [:primary_tag_id, :language_code], unique: true
-
-    add_check_constraint :tag_names,
-                         'primary_flg OR (NOT auto_generated)',
-                         name: 'chk_tag_names_auto_generated_primary'
-  end
-
-  def down
-    remove_check_constraint :tag_names,
-                            name: 'chk_tag_names_auto_generated_primary'
-
-    remove_index :tag_names, [:primary_tag_id, :language_code]
-    remove_column :tag_names, :primary_tag_id
-
-    remove_foreign_key :tag_names, column: :language_code
-    remove_foreign_key :tag_names, column: :script_code
-
-    remove_index :tag_names, [:language_code, :name]
-    add_index :tag_names, :name, unique: true
-
-    remove_column :tag_names, :auto_generated
-    remove_column :tag_names, :primary_flg
-    remove_column :tag_names, :script_code
-    remove_column :tag_names, :language_code
-    remove_reference :tag_names, :tag, foreign_key: true
-  end
-end

backend/db/migrate/20260922040000_add_names_to_tag_versions.rb

@@ -1,68 +0,0 @@
-class AddNamesToTagVersions < ActiveRecord::Migration[8.0]
-  class TagVersion < ActiveRecord::Base
-    self.table_name = 'tag_versions'
-  end
-
-  def up
-    add_column :tag_versions, :names, :json
-    TagVersion.reset_column_information
-
-    say_with_time 'Backfilling multilingual tag version names' do
-      TagVersion.find_each do |version|
-        aliases = version.aliases.to_s.split.filter_map do |name|
-          name.present? && { name:, script_code: 'Jpan' }
-        end
-        names = { ja: { name: version.name,
-                        script_code: 'Jpan',
-                        auto_generated: false,
-                        aliases: } }
-        version.update_columns(names:)
-      end
-    end
-
-    add_names_constraint!
-
-    change_column_null :tag_versions, :names, false
-  end
-
-  def down
-    remove_check_constraint :tag_versions,
-                            name: 'chk_tag_versions_names_schema'
-
-    remove_column :tag_versions, :names
-  end
-
-  private
-
-  def add_names_constraint!
-    schema = { type: 'object',
-               minProperties: 1,
-               patternProperties: { '^.{1,16}$': name_schema },
-               additionalProperties: false }
-
-    quoted_schema = connection.quote(JSON.generate(schema))
-
-    add_check_constraint :tag_versions,
-                         "JSON_SCHEMA_VALID(#{ quoted_schema }, names)",
-                         name: 'chk_tag_versions_names_schema'
-  end
-
-  def name_schema
-    { type: 'object',
-      required: ['name', 'script_code', 'auto_generated', 'aliases'],
-      properties: { **name_schema_base,
-                    auto_generated: { type: 'boolean' },
-                    aliases: { type: 'array',
-                               uniqueItems: true,
-                               items: { type: 'object',
-                                        required: ['name', 'script_code'],
-                                        properties: name_schema_base,
-                                        additionalProperties: false } } },
-      additionalProperties: false }
-  end
-
-  def name_schema_base
-    { name: { type: 'string', minLength: 1, maxLength: 255 },
-      script_code: { type: 'string', pattern: '^[A-Z][a-z]{3}$' } }
-  end
-end

backend/db/migrate/20261003000000_create_tag_descriptions.rb

@@ -1,63 +0,0 @@
-class CreateTagDescriptions < ActiveRecord::Migration[8.0]
-  def change
-    create_table :tag_description_versions do |t|
-      t.references :tag, null: false, foreign_key: false
-      t.string :language_code, limit: 16, null: false
-      t.integer :version_no, null: false
-      t.string :event_type, null: false
-      t.text :body, null: false
-      t.string :source_language_code, limit: 16
-      t.integer :source_version_no
-      t.references :created_by_user
-      t.datetime :created_at, null: false
-
-      t.index [:tag_id, :language_code, :version_no], unique: true
-      t.foreign_key :tag_description_versions,
-                    column: [:tag_id, :source_language_code, :source_version_no],
-                    primary_key: [:tag_id, :language_code, :version_no]
-
-      t.check_constraint 'version_no > 0',
-                         name: 'chk_tag_description_versions_version_no_positive'
-
-      t.check_constraint "event_type IN ('create', 'update', 'discard', 'restore')",
-                         name: 'tag_description_versions_event_type_valid'
-
-      t.check_constraint ('(source_language_code IS NULL AND source_version_no IS NULL) OR ' +
-                          '(source_language_code IS NOT NULL AND source_version_no IS NOT NULL)'),
-                         name: 'chk_tag_description_versions_source_pair'
-
-      t.check_constraint 'source_language_code IS NULL OR source_language_code <> language_code',
-                         name: 'chk_tag_description_versions_source_language_code_different'
-    end
-
-    create_table :tag_descriptions do |t|
-      t.references :tag, null: false, foreign_key: true
-      t.string :language_code, limit: 16, null: false, index: true
-      t.integer :version_no, null: false
-      t.text :body, null: false
-      t.string :source_language_code, limit: 16
-      t.integer :source_version_no
-      t.references :created_by_user, foreign_key: { to_table: :users }
-      t.references :updated_by_user, foreign_key: { to_table: :users }
-      t.timestamps
-
-      t.foreign_key :languages, column: :language_code, primary_key: :code
-      t.foreign_key :tag_description_versions,
-                    column: [:tag_id, :source_language_code, :source_version_no],
-                    primary_key: [:tag_id, :language_code, :version_no]
-
-      t.index [:tag_id, :language_code], unique: true
-      t.index [:source_language_code, :source_version_no]
-
-      t.check_constraint 'version_no > 0',
-                         name: 'chk_tag_descriptions_version_no_positive'
-
-      t.check_constraint ('(source_language_code IS NULL AND source_version_no IS NULL) OR ' +
-                          '(source_language_code IS NOT NULL AND source_version_no IS NOT NULL)'),
-                         name: 'chk_tag_descriptions_source_pair'
-
-      t.check_constraint 'source_language_code IS NULL OR source_language_code <> language_code',
-                         name: 'chk_tag_descriptions_source_language_code_different'
-    end
-  end
-end

backend/db/migrate/20261003010000_migrate_tag_descriptions_from_wiki_pages.rb

@@ -1,104 +0,0 @@
-class MigrateTagDescriptionsFromWikiPages < ActiveRecord::Migration[8.0]
-  class WikiPage < ActiveRecord::Base
-    self.table_name = 'wiki_pages'
-  end
-
-  class WikiRevision < ActiveRecord::Base
-    self.table_name = 'wiki_revisions'
-  end
-
-  class WikiRevisionLine < ActiveRecord::Base
-    self.table_name = 'wiki_revision_lines'
-  end
-
-  class TagName < ActiveRecord::Base
-    self.table_name = 'tag_names'
-  end
-
-  class TagDescription < ActiveRecord::Base
-    self.table_name = 'tag_descriptions'
-  end
-
-  class TagDescriptionVersion < ActiveRecord::Base
-    self.table_name = 'tag_description_versions'
-  end
-
-  def up
-    WikiPage.find_each do |page|
-      tag_name = TagName.find_by(id: page.tag_name_id, language_code: 'ja')
-      next unless tag_name&.tag_id
-
-      revisions = WikiRevision.where(wiki_page_id: page.id).order(:id).to_a
-
-      revisions.each_with_index do |revision, index|
-        version_no = index + 1
-
-        tag_id = tag_name[:tag_id]
-
-        unless tag_id
-          raise (
-              'tag_id is nil: ' +
-              "wiki_page_id=#{ page.id }, " +
-              "tag_name_id=#{ tag_name.id }, " +
-              "tag_name=#{ tag_name.attributes.inspect}")
-        end
-
-        revision_id = revision.id
-
-        say (
-            "wiki_page_id=#{ page.id }, " +
-            "tag_name_id=#{ tag_name.id }, " +
-            "tag_id=#{ tag_id }, " +
-            "revision_id=#{ revision_id }")
-
-        version = TagDescriptionVersion.new(
-            id: revision_id,
-            tag_id:,
-            language_code: 'ja',
-            version_no:,
-            event_type: version_no == 1 ? 'create' : 'update',
-            body: revision_body(revision_id),
-            source_language_code: nil,
-            source_version_no: nil,
-            created_by_user_id: revision.created_user_id,
-            created_at: revision.created_at)
-
-        say version.attributes.inspect
-
-        version.save!
-      end
-
-      next if page.discarded_at.present?
-      next if revisions.empty?
-
-      TagDescription.create!(
-          id: page.id,
-          tag_id: tag_name.tag_id,
-          language_code: 'ja',
-          version_no: revisions.length,
-          body: page.body,
-          source_language_code: nil,
-          source_version_no: nil,
-          created_by_user_id: page.created_user_id,
-          updated_by_user_id: page.updated_user_id,
-          created_at: page.created_at,
-          updated_at: page.updated_at)
-    end
-  end
-
-  def down
-    raise ActiveRecord::IrreversibleMigration, '戻せません．'
-  end
-
-  private
-
-  def revision_body revision_id
-    WikiRevisionLine
-        .joins('INNER JOIN wiki_lines ' +
-               'ON wiki_lines.id = wiki_revision_lines.wiki_line_id')
-        .where(wiki_revision_id: revision_id)
-        .order(:position)
-        .pluck('wiki_lines.body')
-        .join("\n")
-  end
-end

backend/db/migrate/20261005000000_repair_wiki_updated_at.rb

@@ -1,53 +0,0 @@
-class RepairWikiUpdatedAt < ActiveRecord::Migration[8.0]
-  class WikiPage < ActiveRecord::Base
-    self.table_name = 'wiki_pages'
-  end
-
-  class WikiVersion < ActiveRecord::Base
-    self.table_name = 'wiki_versions'
-  end
-
-  class TagDescription < ActiveRecord::Base
-    self.table_name = 'tag_descriptions'
-  end
-
-  class TagDescriptionVersion < ActiveRecord::Base
-    self.table_name = 'tag_description_versions'
-  end
-
-  def up
-    say_with_time 'Repairing wiki_pages.updated_at from wiki_versions' do
-      WikiPage.find_each do |page|
-        version =
-            WikiVersion
-            .where(wiki_page_id: page.id)
-            .order(version_no: :desc)
-            .first
-
-        next unless version
-
-        page.update_columns(updated_at: version.created_at)
-      end
-    end
-
-    say_with_time 'Repairing tag_descriptions.updated_at from tag_description_versions' do
-      TagDescription.find_each do |description|
-        version =
-            TagDescriptionVersion
-            .where(
-                tag_id: description.tag_id,
-                language_code: description.language_code)
-            .order(version_no: :desc)
-            .first
-
-        next unless version
-
-        description.update_columns(updated_at: version.created_at)
-      end
-    end
-  end
-
-  def down
-    ;
-  end
-end

backend/db/migrate/20261008000000_create_tag_groups.rb

@@ -1,149 +0,0 @@
-class CreateTagGroups < ActiveRecord::Migration[8.0]
-  def change
-    # 翻訳系は上流の Translation リソースが未完のため保留
-
-    create_table :tag_groups do |t|
-      t.integer :version_no, null: false
-      t.string :name, limit: 255, null: false
-      t.text :description
-      t.references :created_by_user, foreign_key: { to_table: :users }
-      t.references :updated_by_user, foreign_key: { to_table: :users }
-      t.timestamps
-
-      t.check_constraint 'version_no > 0', name: 'chk_tag_groups_version_no_positive'
-      t.index :name, unique: true
-    end
-
-    create_table :tag_group_tags, primary_key: [:tag_group_id, :tag_id] do |t|
-      t.references :tag_group, null: false, foreign_key: true, index: false
-      t.references :tag, null: false, foreign_key: true
-      t.references :created_by_user, foreign_key: { to_table: :users }
-      t.datetime :created_at, null: false
-    end
-
-    create_table :tag_group_groups, primary_key: [:tag_group_id, :child_tag_group_id] do |t|
-      t.references :tag_group, null: false, foreign_key: true, index: false
-      t.references :child_tag_group,
-                   null: false, foreign_key: { to_table: :tag_groups }
-      t.references :created_by_user, foreign_key: { to_table: :users }
-      t.datetime :created_at, null: false
-
-      t.check_constraint 'tag_group_id <> child_tag_group_id',
-                         name: 'chk_tag_group_groups_tag_group_id_not_child_tag_group_id'
-    end
-
-    create_table :tag_group_placements, primary_key: [:tag_group_id, :position] do |t|
-      t.references :tag_group, null: false, foreign_key: true, index: false
-      t.integer :position, null: false
-      t.integer :parent_position
-      t.string :section_name, limit: 255
-      t.text :description
-      t.references :tag
-      t.references :child_tag_group
-      t.references :created_by_user, foreign_key: { to_table: :users }
-      t.references :updated_by_user, foreign_key: { to_table: :users }
-      t.timestamps
-
-      t.foreign_key :tag_group_placements,
-                    column: [:tag_group_id, :parent_position],
-                    primary_key: [:tag_group_id, :position]
-
-      t.foreign_key :tag_group_tags,
-                    column: [:tag_group_id, :tag_id],
-                    primary_key: [:tag_group_id, :tag_id]
-
-      t.foreign_key :tag_group_groups,
-                    column: [:tag_group_id, :child_tag_group_id],
-                    primary_key: [:tag_group_id, :child_tag_group_id]
-
-      t.check_constraint 'position > parent_position',
-                         name: 'chk_tag_group_placements_position_gt_parent_position'
-
-      t.check_constraint ('((section_name IS NOT NULL AND tag_id IS NULL AND child_tag_group_id IS NULL) OR ' +
-                          '(section_name IS NULL AND tag_id IS NOT NULL AND child_tag_group_id IS NULL) OR ' +
-                          '(section_name IS NULL AND tag_id IS NULL AND child_tag_group_id IS NOT NULL)) AND ' +
-                          '(section_name IS NOT NULL OR description IS NULL)'),
-                         name: 'chk_tag_group_placements_references_exclusive'
-    end
-
-    create_table :tag_group_versions do |t|
-      t.references :tag_group, null: false
-      t.integer :version_no, null: false
-      t.string :event_type, null: false
-      t.string :name, limit: 255, null: false
-      t.text :description
-      t.json :members, null: false
-      t.json :placements, null: false
-      t.references :created_by_user
-      t.datetime :created_at, null: false
-
-      t.check_constraint 'version_no > 0',
-                         name: 'chk_tag_group_versions_version_no_positive'
-      t.index [:tag_group_id, :version_no], unique: true
-
-      add_members_constraint!(t)
-      add_placements_constraint!(t)
-    end
-  end
-
-  private
-
-  def add_members_constraint! t
-    schema = { type: 'array',
-               uniqueItems: true,
-               items: member_schema }
-
-    quoted_schema = connection.quote(JSON.generate(schema))
-
-    t.check_constraint "JSON_SCHEMA_VALID(#{ quoted_schema }, members)", 
-                       name: 'chk_tag_group_versions_members_schema'
-  end
-
-  def member_schema
-    { oneOf: [tag_member_schema, group_member_schema] }
-  end
-
-  def tag_member_schema
-    { type: 'object',
-      required: ['tag_id', 'version_no'],
-      properties: { tag_id: { type: 'integer', minimum: 1 },
-                    version_no: { type: 'integer', minimum: 1 } },
-      additionalProperties: false }
-  end
-
-  def group_member_schema
-    { type: 'object',
-      required: ['tag_group_id', 'version_no'],
-      properties: { tag_group_id: { type: 'integer', minimum: 1 },
-                    version_no: { type: 'integer', minimum: 1 } },
-      additionalProperties: false }
-  end
-
-  def add_placements_constraint! t
-    schema = { type: 'array', items: placement_schema(5) }
-
-    quoted_schema = connection.quote(JSON.generate(schema))
-
-    t.check_constraint "JSON_SCHEMA_VALID(#{ quoted_schema }, placements)",
-                       name: 'chk_tag_group_versions_placements_schema'
-  end
-
-  def placement_schema rest
-    { type: 'object',
-      required: ['children'],
-      properties: { section_name: { type: 'string' },
-                    description: { type: ['string', 'null'] },
-                    tag_id: { type: 'integer', minimum: 1 },
-                    tag_group_id: { type: 'integer', minimum: 1 },
-                    children: if rest > 1
-                                { type: 'array', items: placement_schema(rest - 1) }
-                              else
-                                { type: 'array', maxItems: 0 }
-                              end },
-      oneOf: [{ required: ['section_name'] },
-              { required: ['tag_id'] },
-              { required: ['tag_group_id'] }],
-      dependencies: { description: ['section_name'] },
-      additionalProperties: false }
-  end
-end

backend/db/migrate/20261008010000_migrate_tag_groups_from_wiki_pages.rb

@@ -1,518 +0,0 @@
-class MigrateTagGroupsFromWikiPages < ActiveRecord::Migration[8.0]
-  PREFIX = 'タググループ:'
-
-  def up
-    require 'json'
-    require 'time'
-    require 'kramdown'
-    require 'kramdown-parser-gfm'
-
-    assert_empty_destination!
-
-    pages = connection.select_all(<<~SQL).to_a
-      SELECT
-        wp.id
-      , wp.created_user_id
-      , wp.updated_user_id
-      , wp.created_at
-      , wp.updated_at
-      , wp.discarded_at
-      , tn.name
-      FROM
-        wiki_pages wp
-        INNER JOIN
-          tag_names tn
-          ON
-            tn.id = wp.tag_name_id
-      WHERE
-        tn.language_code = 'ja'
-        AND tn.name LIKE #{ quote("#{ PREFIX }%") }
-      ORDER BY
-        wp.id
-    SQL
-
-    return if pages.empty?
-
-    pages.each do |page|
-      if page['discarded_at']
-        say "Wiki ##{ page.fetch('id') }: 破棄済みですが，Revision の移行を継続します．"
-      end
-    end
-
-    tag_ids = load_tag_ids
-    page_ids = pages.map { |page| page.fetch('id').to_i }
-
-    revisions = connection.select_all(<<~SQL).to_a
-      SELECT
-        wr.id
-      , wr.wiki_page_id
-      , wr.kind
-      , wr.redirect_page_id
-      , wr.created_user_id
-      , wr.created_at
-      FROM
-        wiki_revisions wr
-      WHERE
-        wr.wiki_page_id IN (#{ page_ids.join(', ') })
-      ORDER BY
-        wr.wiki_page_id
-      , wr.id
-    SQL
-
-    revisions_by_page = revisions.group_by { |row| row.fetch('wiki_page_id').to_i }
-
-    pages = pages.select do |page|
-      page_id = page.fetch('id').to_i
-      if revisions_by_page.fetch(page_id, []).empty?
-        # tag_groups.version_no > 0 のため，Revision 0 件の Wiki は作成しない．
-        say "Wiki ##{ page_id }: Revision が 0 件のため移行対象から除外します．"
-        false
-      else
-        true
-      end
-    end
-
-    return if pages.empty?
-
-    group_ids = pages.to_h { |page| [page.fetch('name'), page.fetch('id').to_i] }
-    revision_history = pages.to_h do |page|
-      page_id = page.fetch('id').to_i
-      history = revisions_by_page.fetch(page_id).each_with_index.map do |revision, index|
-        { 'id' => revision.fetch('id').to_i,
-          'version_no' => index + 1,
-          'created_at' => revision.fetch('created_at') }
-      end
-      [page_id, history]
-    end
-
-    tag_history = connection.select_all(<<~SQL).to_a.group_by { |row| row.fetch('tag_id').to_i }
-      SELECT
-        tag_id
-      , version_no
-      , created_at
-      FROM
-        tag_versions
-      ORDER BY
-        tag_id
-      , created_at
-      , version_no
-    SQL
-
-    prepared = { }
-    pages.each do |page|
-      page_id = page.fetch('id').to_i
-      history = revisions_by_page.fetch(page_id)
-
-      prepared[page_id] = history.each_with_index.map do |revision, index|
-        context = "Wiki ##{ page_id } / Revision ##{ revision.fetch('id') }"
-        body = revision_body(revision.fetch('id').to_i)
-
-        if revision.fetch('kind').to_i == 1
-          destination = revision['redirect_page_id']
-          description = "旧 Wiki のリダイレクト先: Wiki ##{ destination }"
-          placements = []
-          members = []
-          say "#{ context }: リダイレクトを説明文として移行します．"
-        else
-          begin
-            description, placements = parse_wiki(body, tag_ids, group_ids, context)
-            validate_tree!(placements, context)
-            members = build_members(placements, revision.fetch('created_at'),
-                                    tag_history, revision_history, context)
-          rescue StandardError => error
-            # 解析できない版も捨てず，当時の Markdown を説明文として保存する．
-            say "#{ context }: 構造化を保留し，本文を保存します (#{ error.message })．"
-            description = body
-            placements = []
-            members = []
-          end
-        end
-
-        { revision:, version_no: index + 1, description:, members:, placements:, body: }
-      end
-    end
-
-    # 自己包含は禁止されてゐるため，当該版は原文の保存を優先する．
-    prepared.each do |group_id, versions|
-      current = versions.last
-      next unless current.fetch(:members).any? { |member| member['tag_group_id'] == group_id }
-
-      say "Tag Group ##{ group_id }: 直接の自己参照を検出したため，現行構造化を保留します．"
-      current[:description] = current.fetch(:body)
-      current[:members] = []
-      current[:placements] = []
-    end
-
-    begin
-      validate_current_groups!(prepared)
-    rescue StandardError => error
-      say "Tag Group の包含関係に問題がありますが，移行を継続します (#{ error.message })．"
-    end
-
-    # 移行先の書込みはすべて検証の後．DDL は含めない．
-    connection.transaction do
-      pages.each do |page|
-        page_id = page.fetch('id').to_i
-        current = prepared.fetch(page_id).last
-
-        insert_row('tag_groups', {
-            id: page_id,
-            # page.version_no ではなく，この Wiki に紐付く Revision の総数．
-            version_no: revisions_by_page.fetch(page_id).size,
-            name: page.fetch('name').delete_prefix(PREFIX),
-            description: current.fetch(:description),
-            created_by_user_id: page.fetch('created_user_id'),
-            updated_by_user_id: page.fetch('updated_user_id'),
-            created_at: page.fetch('created_at'),
-            updated_at: page.fetch('updated_at') })
-      end
-
-      pages.each do |page|
-        page_id = page.fetch('id').to_i
-        name = page.fetch('name').delete_prefix(PREFIX)
-
-        prepared.fetch(page_id).each do |item|
-          revision = item.fetch(:revision)
-
-          insert_row('tag_group_versions', {
-              id: revision.fetch('id'),
-              tag_group_id: page_id,
-              version_no: item.fetch(:version_no),
-              event_type: item.fetch(:version_no) == 1 ? 'create' : 'update',
-              name:,
-              description: item.fetch(:description),
-              members: JSON.generate(item.fetch(:members)),
-              placements: JSON.generate(item.fetch(:placements)),
-              created_by_user_id: revision.fetch('created_user_id'),
-              created_at: revision.fetch('created_at') })
-        end
-      end
-
-      pages.each do |page|
-        page_id = page.fetch('id').to_i
-        current = prepared.fetch(page_id).last
-        revision = current.fetch(:revision)
-
-        current.fetch(:members).each do |member|
-          if member.key?('tag_id')
-            insert_row('tag_group_tags', {
-                tag_group_id: page_id,
-                tag_id: member.fetch('tag_id'),
-                created_by_user_id: revision.fetch('created_user_id'),
-                created_at: revision.fetch('created_at') })
-          else
-            insert_row('tag_group_groups', {
-                tag_group_id: page_id,
-                child_tag_group_id: member.fetch('tag_group_id'),
-                created_by_user_id: revision.fetch('created_user_id'),
-                created_at: revision.fetch('created_at') })
-          end
-        end
-      end
-
-      pages.each do |page|
-        page_id = page.fetch('id').to_i
-        current = prepared.fetch(page_id).last
-        revision = current.fetch(:revision)
-        position = 0
-
-        append = -> nodes, parent_position do
-          nodes.each do |node|
-            position += 1
-            own_position = position
-
-            insert_row('tag_group_placements', {
-                tag_group_id: page_id,
-                position: own_position,
-                parent_position:,
-                section_name: node['section_name'],
-                description: node['description'],
-                tag_id: node['tag_id'],
-                child_tag_group_id: node['tag_group_id'],
-                created_by_user_id: revision.fetch('created_user_id'),
-                updated_by_user_id: revision.fetch('created_user_id'),
-                created_at: revision.fetch('created_at'),
-                updated_at: revision.fetch('created_at') })
-
-            append.(node.fetch('children'), own_position)
-          end
-        end
-
-        append.(current.fetch(:placements), nil)
-      end
-    end
-  end
-
-  def down
-    raise ActiveRecord::IrreversibleMigration, '戻せません．'
-  end
-
-  private
-
-  def assert_empty_destination!
-    ['tag_groups', 'tag_group_versions', 'tag_group_tags',
-     'tag_group_groups', 'tag_group_placements'].each do |table|
-      count = connection.select_value("SELECT COUNT(*) FROM #{ table }").to_i
-      raise "#{ table } が空ではありません．" if count.positive?
-    end
-  end
-
-  # 解決は tag_names.name -> tag_names.tag_id のみ．
-  # tags.tag_name_id は読まない．
-  def load_tag_ids
-    rows = connection.select_all(<<~SQL).to_a
-      SELECT
-        name
-      , tag_id
-      FROM
-        tag_names
-      WHERE
-        language_code = 'ja'
-        AND tag_id IS NOT NULL
-    SQL
-
-    rows.each_with_object({ }) do |row, by_name|
-      name = row.fetch('name')
-      id = row.fetch('tag_id').to_i
-      by_name[name] ||= []
-      by_name[name] << id unless by_name[name].include?(id)
-    end
-  end
-
-  def revision_body revision_id
-    connection.select_rows(<<~SQL).flatten.join("\n")
-      SELECT
-        wl.body
-      FROM
-        wiki_revision_lines wrl
-        INNER JOIN wiki_lines wl ON wl.id = wrl.wiki_line_id
-      WHERE
-        wrl.wiki_revision_id = #{ Integer(revision_id) }
-      ORDER BY
-        wrl.position
-    SQL
-  end
-
-  def parse_wiki markdown, tag_ids, group_ids, context
-    root = Kramdown::Document.new(markdown, input: 'GFM').root
-    placements = []
-    description_parts = []
-    headings = []
-
-    root.children.each_with_index do |node, index|
-      case node.type
-      when :blank
-        next
-      when :header
-        level = node.options.fetch(:level)
-        name = inline_text(node).strip
-        raise "#{ context }: 名前のない見出しがあります．" if name.empty?
-
-        headings.pop while headings.any? && headings.last.first >= level
-        parent = headings.last&.last
-        section = { 'section_name' => name, 'description' => nil, 'children' => [] }
-        (parent ? parent.fetch('children') : placements) << section
-        headings << [level, section]
-      when :p
-        text = inline_markdown(node).strip
-        next if text.empty?
-
-        if headings.any?
-          heading = headings.last.last
-          heading['description'] = [heading['description'], text].compact.join("\n\n")
-        else
-          description_parts << text
-        end
-      when :ul, :ol
-        if headings.any? && see_also_heading?(headings.last.last.fetch('section_name'))
-          heading = headings.last.last
-          raw = original_block(markdown, root.children, index)
-          heading['description'] = [heading['description'], raw].compact.join("\n\n")
-        else
-          target = headings.any? ? headings.last.last.fetch('children') : placements
-          target.concat(node.children.map { |item| parse_list_item(item, tag_ids, group_ids, context) })
-        end
-      else
-        raise "#{ context }: 未対応の Markdown 構文 #{ node.type.inspect }"
-      end
-    end
-
-    [description_parts.empty? ? nil : description_parts.join("\n\n"), placements]
-  end
-
-  def see_also_heading? name
-    ['see also', '関連項目'].include?(name.strip.downcase.sub(/[:：]\z/, ''))
-  end
-
-  def original_block markdown, siblings, index
-    current = siblings.fetch(index)
-    start_line = current.options[:location]
-    raise 'Markdown block の位置が不明です．' unless start_line
-
-    following = siblings[(index + 1)..].find do |node|
-      node.options[:location] && node.options[:location] > start_line
-    end
-    end_line = following ? following.options.fetch(:location) - 1 : markdown.lines.length
-    markdown.lines[(start_line - 1)...end_line].join.strip
-  end
-
-  def parse_list_item item, tag_ids, group_ids, context
-    raise "#{ context }: リスト項目ではありません．" if item.type != :li
-
-    nested, own = item.children.partition { |child| [:ul, :ol].include?(child.type) }
-    own.reject! { |child| child.type == :blank }
-    unless own.all? { |child| [:p, :text, :a, :codespan].include?(child.type) }
-      raise "#{ context }: 未対応のリスト項目があります．"
-    end
-
-    label = own.map { |child| inline_text(child) }.join(' ').strip
-    raise "#{ context }: 空のリスト項目があります．" if label.empty?
-
-    node =
-        if group_ids.key?(label)
-          { 'tag_group_id' => group_ids.fetch(label) }
-        elsif tag_ids.key?(label)
-          ids = tag_ids.fetch(label)
-          unless ids.one?
-            raise "#{ context }: タグ名 #{ label.inspect } が複数の ID を指します：#{ ids.inspect }"
-          end
-          { 'tag_id' => ids.first }
-        elsif label.end_with?(':', '：')
-          name = label.sub(/[:：]\z/, '')
-          raise "#{ context }: 空の区分名があります．" if name.empty?
-          if see_also_heading?(name) && nested.any?
-            raise "#{ context }: リスト内の See also は説明文への保管処理が未実装です．"
-          end
-          { 'section_name' => name, 'description' => nil }
-        else
-          raise "#{ context }: 解決不能なリスト項目 #{ label.inspect }"
-        end
-
-    node['children'] = nested.flat_map do |list|
-      list.children.map { |child| parse_list_item(child, tag_ids, group_ids, context) }
-    end
-
-    node
-  end
-
-  def inline_text node
-    case node.type
-    when :text, :codespan
-      node.value.to_s
-    when :softbreak, :br
-      ' '
-    when :a, :p, :header, :em, :strong, :span, :li
-      node.children.map { |child| inline_text(child) }.join
-    else
-      raise "未対応のインライン構文 #{ node.type.inspect }"
-    end
-  end
-
-  def inline_markdown node
-    case node.type
-    when :text
-      node.value.to_s
-    when :codespan
-      "`#{ node.value }`"
-    when :softbreak
-      "\n"
-    when :br
-      "  \n"
-    when :p
-      node.children.map { |child| inline_markdown(child) }.join
-    when :a
-      href = node.attr.fetch('href')
-      "[#{ node.children.map { |child| inline_markdown(child) }.join }](#{ href })"
-    when :em
-      "*#{ node.children.map { |child| inline_markdown(child) }.join }*"
-    when :strong
-      "**#{ node.children.map { |child| inline_markdown(child) }.join }**"
-    else
-      raise "未対応のインライン構文 #{ node.type.inspect }"
-    end
-  end
-
-  def validate_tree! nodes, context, depth = 1
-    raise "#{ context }: 配置の深さが 5 を超えてゐます．" if depth > 5 && nodes.any?
-
-    nodes.each do |node|
-      name = node['section_name']
-      if name && name.length > 255
-        raise "#{ context }: 区分名が 255 文字を超えてゐます．"
-      end
-      validate_tree!(node.fetch('children'), context, depth + 1)
-    end
-  end
-
-  def build_members nodes, date, tag_history, group_history, context
-    ids_of_tags = []
-    ids_of_groups = []
-
-    visit = -> items do
-      items.each do |node|
-        ids_of_tags << node['tag_id'] if node.key?('tag_id')
-        ids_of_groups << node['tag_group_id'] if node.key?('tag_group_id')
-        visit.(node.fetch('children'))
-      end
-    end
-    visit.(nodes)
-
-    tags = ids_of_tags.uniq.map do |id|
-      { 'tag_id' => id,
-        'version_no' => version_at(tag_history[id], date, context, "Tag ##{ id }") }
-    end
-
-    groups = ids_of_groups.uniq.map do |id|
-      { 'tag_group_id' => id,
-        'version_no' => version_at(group_history[id], date, context, "TagGroup ##{ id }") }
-    end
-
-    tags + groups
-  end
-
-  def version_at history, date, context, target
-    raise "#{ context }: #{ target } の履歴が存在しません．" unless history&.any?
-
-    timestamp = Time.parse(date.to_s)
-    candidates = history.select do |row|
-      Time.parse(row.fetch('created_at').to_s) <= timestamp
-    end
-    if candidates.empty?
-      raise "#{ context }: #{ target } は #{ date } 時点で存在しません．"
-    end
-
-    candidates.max_by { |row|
-      [Time.parse(row.fetch('created_at').to_s), row.fetch('version_no').to_i]
-    }.fetch('version_no').to_i
-  end
-
-  def validate_current_groups! prepared
-    edges = { }
-    prepared.each do |group_id, versions|
-      edges[group_id] = versions.last.fetch(:members)
-                              .filter_map { |member| member['tag_group_id'] }
-    end
-
-    visiting = { }
-    visited = { }
-    visit = -> group_id do
-      raise "Tag Group の循環参照を検出しました：#{ group_id }" if visiting[group_id]
-      return if visited[group_id]
-
-      visiting[group_id] = true
-      edges.fetch(group_id, []).each { |child_id| visit.(child_id) }
-      visiting.delete(group_id)
-      visited[group_id] = true
-    end
-
-    edges.keys.each { |group_id| visit.(group_id) }
-  end
-
-  def quote(value) = connection.quote(value)
-
-  def insert_row table, values
-    columns = values.keys.join(', ')
-    payload = values.values.map { |value| quote(value) }.join(', ')
-    execute "INSERT INTO #{ table } (#{ columns }) VALUES (#{ payload })"
-  end
-end

backend/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
+ActiveRecord::Schema[8.0].define(version: 2026_07_27_123600) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -48,14 +48,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
     t.index ["tag_id"], name: "index_deerjikists_on_tag_id"
   end
 
-  create_table "external_tags", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "platform", limit: 16, null: false
-    t.string "name", null: false
-    t.integer "post_count", default: 0, null: false
-    t.datetime "created_at", null: false
-    t.index ["platform", "name"], name: "index_external_tags_on_platform_and_name", unique: true
-  end
-
   create_table "gekanator_ai_runs", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "model", null: false
     t.integer "input_tokens", default: 0, null: false
@@ -138,29 +130,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
     t.index ["ip_address"], name: "index_ip_addresses_on_ip_address", unique: true
   end
 
-  create_table "languages", primary_key: "code", id: { type: :string, limit: 16 }, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "name", null: false
-    t.datetime "deprecated_at"
-    t.datetime "created_at", null: false
-    t.index ["deprecated_at"], name: "index_languages_on_deprecated_at"
-  end
-
-  create_table "locales", primary_key: "code", id: { type: :string, limit: 32 }, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "language_code", limit: 16, null: false
-    t.string "script_code", limit: 4, null: false
-    t.integer "region_code", limit: 2, null: false
-    t.string "variants", default: "", null: false
-    t.string "name", null: false
-    t.datetime "deprecated_at"
-    t.datetime "created_at", null: false
-    t.index ["deprecated_at"], name: "index_locales_on_deprecated_at"
-    t.index ["language_code", "script_code", "region_code", "variants"], name: "idx_on_language_code_script_code_region_code_varian_b0ba85c39a", unique: true
-    t.index ["language_code"], name: "index_locales_on_language_code"
-    t.index ["region_code"], name: "fk_rails_175159992c"
-    t.index ["script_code"], name: "fk_rails_0b74ce96a8"
-    t.check_constraint "regexp_like(`variants`,_utf8mb4'^((([a-z0-9]{5,8}|[0-9][a-z0-9]{3})(-([a-z0-9]{5,8}|[0-9][a-z0-9]{3}))*(-x(-[a-z0-9]{1,8})+)?)|(x(-[a-z0-9]{1,8})+))?$',_utf8mb4'c')", name: "locales_variants_check"
-  end
-
   create_table "material_export_items", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "material_id", null: false
     t.string "profile", default: "legacy_drive", null: false
@@ -312,13 +281,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
     t.check_constraint "`version_no` > 0", name: "nico_tag_versions_version_no_positive"
   end
 
-  create_table "post_external_tags", primary_key: ["post_id", "external_tag_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "post_id", null: false
-    t.bigint "external_tag_id", null: false
-    t.datetime "created_at", null: false
-    t.index ["external_tag_id"], name: "index_post_external_tags_on_external_tag_id"
-  end
-
   create_table "post_implications", primary_key: ["post_id", "parent_post_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "post_id", null: false
     t.bigint "parent_post_id", null: false
@@ -349,12 +311,23 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
     t.check_constraint "`begin_ms` >= 0", name: "chk_post_tag_sections_begin_ms_natural"
   end
 
-  create_table "post_tags", primary_key: ["post_id", "tag_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+  create_table "post_tags", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "post_id", null: false
     t.bigint "tag_id", null: false
     t.bigint "created_user_id"
+    t.bigint "deleted_user_id"
     t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.datetime "discarded_at"
+    t.virtual "is_active", type: :boolean, as: "(`discarded_at` is null)", stored: true
+    t.virtual "active_unique_key", type: :string, as: "(case when (`discarded_at` is null) then concat(`post_id`,_utf8mb4':',`tag_id`) else NULL end)", stored: true
+    t.index ["active_unique_key"], name: "idx_post_tags_active_unique", unique: true
     t.index ["created_user_id"], name: "index_post_tags_on_created_user_id"
+    t.index ["deleted_user_id"], name: "index_post_tags_on_deleted_user_id"
+    t.index ["discarded_at"], name: "index_post_tags_on_discarded_at"
+    t.index ["post_id", "discarded_at"], name: "index_post_tags_on_post_id_and_discarded_at"
+    t.index ["post_id"], name: "index_post_tags_on_post_id"
+    t.index ["tag_id", "discarded_at"], name: "index_post_tags_on_tag_id_and_discarded_at"
     t.index ["tag_id"], name: "index_post_tags_on_tag_id"
   end
 
@@ -390,7 +363,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
     t.check_constraint "(`video_ms` is null) or (`video_ms` > 0)", name: "chk_post_versions_video_ms_positive"
     t.check_constraint "`event_type` in (_utf8mb4'create',_utf8mb4'update',_utf8mb4'discard',_utf8mb4'restore')", name: "post_versions_event_type_valid"
     t.check_constraint "`version_no` > 0", name: "post_versions_version_no_positive"
-    t.check_constraint "json_schema_valid(_utf8mb4'{\"type\":\"array\",\"items\":{\"oneOf\":[{\"type\":\"object\",\"properties\":{\"tag_id\":{\"type\":\"integer\",\"minimum\":1},\"version_no\":{\"type\":\"integer\",\"minimum\":1},\"name\":{\"type\":\"string\",\"minLength\":1},\"category\":{\"type\":\"string\",\"enum\":[\"deerjikist\",\"meme\",\"character\",\"general\",\"material\",\"meta\"]},\"sections\":{\"type\":\"array\",\"items\":{\"type\":\"object\",\"properties\":{\"begin_ms\":{\"type\":\"integer\",\"minimum\":0},\"end_ms\":{\"type\":[\"integer\",\"null\"],\"minimum\":0}},\"required\":[\"begin_ms\",\"end_ms\"],\"additionalProperties\":false}}},\"required\":[\"tag_id\",\"version_no\",\"sections\"],\"additionalProperties\":false},{\"type\":\"object\",\"properties\":{\"external_tag_id\":{\"type\":\"integer\",\"minimum\":1}},\"required\":[\"external_tag_id\"],\"additionalProperties\":false}]}}',`tags_json`)", name: "chk_post_versions_tags_json_schema"
+    t.check_constraint "json_schema_valid(_utf8mb4'{\"type\":\"array\",\"items\":{\"type\":\"object\",\"properties\":{\"id\":{\"type\":\"integer\",\"minimum\":1},\"version_no\":{\"type\":\"integer\",\"minimum\":1},\"name\":{\"type\":\"string\",\"minLength\":1},\"category\":{\"type\":\"string\",\"enum\":[\"deerjikist\",\"meme\",\"character\",\"general\",\"material\",\"meta\",\"nico\"]},\"sections\":{\"type\":\"array\",\"items\":{\"type\":\"object\",\"properties\":{\"begin_ms\":{\"type\":\"integer\",\"minimum\":0},\"end_ms\":{\"type\":[\"integer\",\"null\"],\"minimum\":0}},\"required\":[\"begin_ms\",\"end_ms\"],\"additionalProperties\":false}}},\"required\":[\"id\",\"version_no\",\"name\",\"category\",\"sections\"],\"additionalProperties\":false}}',`tags_json`)", name: "chk_post_versions_tags_json_schema"
   end
 
   create_table "posts", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -411,24 +384,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
     t.check_constraint "`version_no` > 0", name: "chk_posts_version_no_positive"
   end
 
-  create_table "regions", primary_key: "code", id: { type: :integer, limit: 2 }, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "alpha_code", limit: 2
-    t.string "name", null: false
-    t.datetime "deprecated_at"
-    t.datetime "created_at", null: false
-    t.index ["alpha_code"], name: "index_regions_on_alpha_code", unique: true
-    t.index ["deprecated_at"], name: "index_regions_on_deprecated_at"
-    t.check_constraint "regexp_like(`alpha_code`,_utf8mb4'^[A-Z]{2}$',_utf8mb4'c')", name: "regions_alpha_code_check"
-  end
-
-  create_table "scripts", primary_key: "code", id: { type: :string, limit: 4 }, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "name", null: false
-    t.datetime "deprecated_at"
-    t.datetime "created_at", null: false
-    t.index ["deprecated_at"], name: "index_scripts_on_deprecated_at"
-    t.check_constraint "regexp_like(`code`,_utf8mb4'^[A-Z][a-z]{3}$',_utf8mb4'c')", name: "scripts_code_check"
-  end
-
   create_table "settings", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "user_id", null: false
     t.datetime "created_at", null: false
@@ -440,121 +395,17 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
     t.index ["user_id"], name: "index_settings_on_user_id", unique: true
   end
 
-  create_table "tag_description_versions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+  create_table "wiki_assets", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "tag_id", null: false
+    t.bigint "wiki_page_id", null: false
-    t.string "language_code", limit: 16, null: false
+    t.integer "no", null: false
-    t.integer "version_no", null: false
+    t.string "alt_text"
-    t.string "event_type", null: false
+    t.binary "sha256", limit: 32, null: false
-    t.text "body", null: false
+    t.bigint "created_by_user_id", null: false
-    t.string "source_language_code", limit: 16
-    t.integer "source_version_no"
-    t.bigint "created_by_user_id"
-    t.datetime "created_at", null: false
-    t.index ["created_by_user_id"], name: "index_tag_description_versions_on_created_by_user_id"
-    t.index ["tag_id", "language_code", "version_no"], name: "idx_on_tag_id_language_code_version_no_ced77e57e6", unique: true
-    t.index ["tag_id", "source_language_code", "source_version_no"], name: "fk_rails_4f13094dbc"
-    t.index ["tag_id"], name: "index_tag_description_versions_on_tag_id"
-    t.check_constraint "((`source_language_code` is null) and (`source_version_no` is null)) or ((`source_language_code` is not null) and (`source_version_no` is not null))", name: "chk_tag_description_versions_source_pair"
-    t.check_constraint "(`source_language_code` is null) or (`source_language_code` <> `language_code`)", name: "chk_tag_description_versions_source_language_code_different"
-    t.check_constraint "`event_type` in (_utf8mb4'create',_utf8mb4'update',_utf8mb4'discard',_utf8mb4'restore')", name: "tag_description_versions_event_type_valid"
-    t.check_constraint "`version_no` > 0", name: "chk_tag_description_versions_version_no_positive"
-  end
-
-  create_table "tag_descriptions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "tag_id", null: false
-    t.string "language_code", limit: 16, null: false
-    t.integer "version_no", null: false
-    t.text "body", null: false
-    t.string "source_language_code", limit: 16
-    t.integer "source_version_no"
-    t.bigint "created_by_user_id"
-    t.bigint "updated_by_user_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["created_by_user_id"], name: "index_tag_descriptions_on_created_by_user_id"
+    t.index ["created_by_user_id"], name: "index_wiki_assets_on_created_by_user_id"
-    t.index ["language_code"], name: "index_tag_descriptions_on_language_code"
+    t.index ["wiki_page_id", "no"], name: "index_wiki_assets_on_wiki_page_id_and_no", unique: true
-    t.index ["source_language_code", "source_version_no"], name: "idx_on_source_language_code_source_version_no_00117fe02a"
+    t.index ["wiki_page_id", "sha256"], name: "index_wiki_assets_on_wiki_page_id_and_sha256", unique: true
-    t.index ["tag_id", "language_code"], name: "index_tag_descriptions_on_tag_id_and_language_code", unique: true
-    t.index ["tag_id", "source_language_code", "source_version_no"], name: "fk_rails_d1be0a7696"
-    t.index ["tag_id"], name: "index_tag_descriptions_on_tag_id"
-    t.index ["updated_by_user_id"], name: "index_tag_descriptions_on_updated_by_user_id"
-    t.check_constraint "((`source_language_code` is null) and (`source_version_no` is null)) or ((`source_language_code` is not null) and (`source_version_no` is not null))", name: "chk_tag_descriptions_source_pair"
-    t.check_constraint "(`source_language_code` is null) or (`source_language_code` <> `language_code`)", name: "chk_tag_descriptions_source_language_code_different"
-    t.check_constraint "`version_no` > 0", name: "chk_tag_descriptions_version_no_positive"
-  end
-
-  create_table "tag_group_groups", primary_key: ["tag_group_id", "child_tag_group_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "tag_group_id", null: false
-    t.bigint "child_tag_group_id", null: false
-    t.bigint "created_by_user_id"
-    t.datetime "created_at", null: false
-    t.index ["child_tag_group_id"], name: "index_tag_group_groups_on_child_tag_group_id"
-    t.index ["created_by_user_id"], name: "index_tag_group_groups_on_created_by_user_id"
-    t.check_constraint "`tag_group_id` <> `child_tag_group_id`", name: "chk_tag_group_groups_tag_group_id_not_child_tag_group_id"
-  end
-
-  create_table "tag_group_placements", primary_key: ["tag_group_id", "position"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "tag_group_id", null: false
-    t.integer "position", null: false
-    t.integer "parent_position"
-    t.string "section_name"
-    t.text "description"
-    t.bigint "tag_id"
-    t.bigint "child_tag_group_id"
-    t.bigint "created_by_user_id"
-    t.bigint "updated_by_user_id"
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["child_tag_group_id"], name: "index_tag_group_placements_on_child_tag_group_id"
-    t.index ["created_by_user_id"], name: "index_tag_group_placements_on_created_by_user_id"
-    t.index ["tag_group_id", "child_tag_group_id"], name: "fk_rails_7342b54ced"
-    t.index ["tag_group_id", "parent_position"], name: "fk_rails_3af6ee71ca"
-    t.index ["tag_group_id", "tag_id"], name: "fk_rails_365dc60759"
-    t.index ["tag_id"], name: "index_tag_group_placements_on_tag_id"
-    t.index ["updated_by_user_id"], name: "index_tag_group_placements_on_updated_by_user_id"
-    t.check_constraint "(((`section_name` is not null) and (`tag_id` is null) and (`child_tag_group_id` is null)) or ((`section_name` is null) and (`tag_id` is not null) and (`child_tag_group_id` is null)) or ((`section_name` is null) and (`tag_id` is null) and (`child_tag_group_id` is not null))) and ((`section_name` is not null) or (`description` is null))", name: "chk_tag_group_placements_references_exclusive"
-    t.check_constraint "`position` > `parent_position`", name: "chk_tag_group_placements_position_gt_parent_position"
-  end
-
-  create_table "tag_group_tags", primary_key: ["tag_group_id", "tag_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "tag_group_id", null: false
-    t.bigint "tag_id", null: false
-    t.bigint "created_by_user_id"
-    t.datetime "created_at", null: false
-    t.index ["created_by_user_id"], name: "index_tag_group_tags_on_created_by_user_id"
-    t.index ["tag_id"], name: "index_tag_group_tags_on_tag_id"
-  end
-
-  create_table "tag_group_versions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "tag_group_id", null: false
-    t.integer "version_no", null: false
-    t.string "event_type", null: false
-    t.string "name", null: false
-    t.text "description"
-    t.json "members", null: false
-    t.json "placements", null: false
-    t.bigint "created_by_user_id"
-    t.datetime "created_at", null: false
-    t.index ["created_by_user_id"], name: "index_tag_group_versions_on_created_by_user_id"
-    t.index ["tag_group_id", "version_no"], name: "index_tag_group_versions_on_tag_group_id_and_version_no", unique: true
-    t.index ["tag_group_id"], name: "index_tag_group_versions_on_tag_group_id"
-    t.check_constraint "`version_no` > 0", name: "chk_tag_group_versions_version_no_positive"
-    t.check_constraint "json_schema_valid(_utf8mb4'{\"type\":\"array\",\"items\":{\"type\":\"object\",\"required\":[\"children\"],\"properties\":{\"section_name\":{\"type\":\"string\"},\"description\":{\"type\":[\"string\",\"null\"]},\"tag_id\":{\"type\":\"integer\",\"minimum\":1},\"tag_group_id\":{\"type\":\"integer\",\"minimum\":1},\"children\":{\"type\":\"array\",\"items\":{\"type\":\"object\",\"required\":[\"children\"],\"properties\":{\"section_name\":{\"type\":\"string\"},\"description\":{\"type\":[\"string\",\"null\"]},\"tag_id\":{\"type\":\"integer\",\"minimum\":1},\"tag_group_id\":{\"type\":\"integer\",\"minimum\":1},\"children\":{\"type\":\"array\",\"items\":{\"type\":\"object\",\"required\":[\"children\"],\"properties\":{\"section_name\":{\"type\":\"string\"},\"description\":{\"type\":[\"string\",\"null\"]},\"tag_id\":{\"type\":\"integer\",\"minimum\":1},\"tag_group_id\":{\"type\":\"integer\",\"minimum\":1},\"children\":{\"type\":\"array\",\"items\":{\"type\":\"object\",\"required\":[\"children\"],\"properties\":{\"section_name\":{\"type\":\"string\"},\"description\":{\"type\":[\"string\",\"null\"]},\"tag_id\":{\"type\":\"integer\",\"minimum\":1},\"tag_group_id\":{\"type\":\"integer\",\"minimum\":1},\"children\":{\"type\":\"array\",\"items\":{\"type\":\"object\",\"required\":[\"children\"],\"properties\":{\"section_name\":{\"type\":\"string\"},\"description\":{\"type\":[\"string\",\"null\"]},\"tag_id\":{\"type\":\"integer\",\"minimum\":1},\"tag_group_id\":{\"type\":\"integer\",\"minimum\":1},\"children\":{\"type\":\"array\",\"maxItems\":0}},\"oneOf\":[{\"required\":[\"section_name\"]},{\"required\":[\"tag_id\"]},{\"required\":[\"tag_group_id\"]}],\"dependencies\":{\"description\":[\"section_name\"]},\"additionalProperties\":false}}},\"oneOf\":[{\"required\":[\"section_name\"]},{\"required\":[\"tag_id\"]},{\"required\":[\"tag_group_id\"]}],\"dependencies\":{\"description\":[\"section_name\"]},\"additionalProperties\":false}}},\"oneOf\":[{\"required\":[\"section_name\"]},{\"required\":[\"tag_id\"]},{\"required\":[\"tag_group_id\"]}],\"dependencies\":{\"description\":[\"section_name\"]},\"additionalProperties\":false}}},\"oneOf\":[{\"required\":[\"section_name\"]},{\"required\":[\"tag_id\"]},{\"required\":[\"tag_group_id\"]}],\"dependencies\":{\"description\":[\"section_name\"]},\"additionalProperties\":false}}},\"oneOf\":[{\"required\":[\"section_name\"]},{\"required\":[\"tag_id\"]},{\"required\":[\"tag_group_id\"]}],\"dependencies\":{\"description\":[\"section_name\"]},\"additionalProperties\":false}}',`placements`)", name: "chk_tag_group_versions_placements_schema"
-    t.check_constraint "json_schema_valid(_utf8mb4'{\"type\":\"array\",\"uniqueItems\":true,\"items\":{\"oneOf\":[{\"type\":\"object\",\"required\":[\"tag_id\",\"version_no\"],\"properties\":{\"tag_id\":{\"type\":\"integer\",\"minimum\":1},\"version_no\":{\"type\":\"integer\",\"minimum\":1}},\"additionalProperties\":false},{\"type\":\"object\",\"required\":[\"tag_group_id\",\"version_no\"],\"properties\":{\"tag_group_id\":{\"type\":\"integer\",\"minimum\":1},\"version_no\":{\"type\":\"integer\",\"minimum\":1}},\"additionalProperties\":false}]}}',`members`)", name: "chk_tag_group_versions_members_schema"
-  end
-
-  create_table "tag_groups", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.integer "version_no", null: false
-    t.string "name", null: false
-    t.text "description"
-    t.bigint "created_by_user_id"
-    t.bigint "updated_by_user_id"
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["created_by_user_id"], name: "index_tag_groups_on_created_by_user_id"
-    t.index ["name"], name: "index_tag_groups_on_name", unique: true
-    t.index ["updated_by_user_id"], name: "index_tag_groups_on_updated_by_user_id"
-    t.check_constraint "`version_no` > 0", name: "chk_tag_groups_version_no_positive"
   end
 
   create_table "tag_implications", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -578,22 +429,14 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
   end
 
   create_table "tag_names", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "tag_id"
-    t.string "language_code", limit: 16, null: false
     t.string "name", null: false
-    t.string "script_code", limit: 4, null: false
-    t.boolean "primary_flg", null: false
-    t.boolean "auto_generated", default: false, null: false
     t.bigint "canonical_id"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.virtual "primary_tag_id", type: :bigint, as: "(case when `primary_flg` then `tag_id` else NULL end)"
+    t.datetime "discarded_at"
     t.index ["canonical_id"], name: "index_tag_names_on_canonical_id"
-    t.index ["language_code", "name"], name: "index_tag_names_on_language_code_and_name", unique: true
+    t.index ["discarded_at"], name: "index_tag_names_on_discarded_at"
-    t.index ["primary_tag_id", "language_code"], name: "index_tag_names_on_primary_tag_id_and_language_code", unique: true
+    t.index ["name"], name: "index_tag_names_on_name", unique: true
-    t.index ["script_code"], name: "fk_rails_dd783b3d1c"
-    t.index ["tag_id"], name: "index_tag_names_on_tag_id"
-    t.check_constraint "(0 <> `primary_flg`) or (0 = `auto_generated`)", name: "chk_tag_names_auto_generated_primary"
   end
 
   create_table "tag_similarities", primary_key: ["tag_id", "target_tag_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -615,13 +458,11 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
     t.datetime "deprecated_at"
     t.datetime "created_at", null: false
     t.bigint "created_by_user_id"
-    t.json "names", null: false
     t.index ["created_at"], name: "index_tag_versions_on_created_at"
     t.index ["created_by_user_id", "created_at"], name: "index_tag_versions_on_created_by_user_id_and_created_at", order: { created_at: :desc }
     t.index ["tag_id", "created_at"], name: "index_tag_versions_on_tag_id_and_created_at", order: { created_at: :desc }
     t.index ["tag_id", "version_no"], name: "index_tag_versions_on_tag_id_and_version_no", unique: true
     t.check_constraint "`version_no` > 0", name: "tag_versions_version_no_positive"
-    t.check_constraint "json_schema_valid(_utf8mb4'{\"type\":\"object\",\"minProperties\":1,\"patternProperties\":{\"^.{1,16}$\":{\"type\":\"object\",\"required\":[\"name\",\"script_code\",\"auto_generated\",\"aliases\"],\"properties\":{\"name\":{\"type\":\"string\",\"minLength\":1,\"maxLength\":255},\"script_code\":{\"type\":\"string\",\"pattern\":\"^[A-Z][a-z]{3}$\"},\"auto_generated\":{\"type\":\"boolean\"},\"aliases\":{\"type\":\"array\",\"uniqueItems\":true,\"items\":{\"type\":\"object\",\"required\":[\"name\",\"script_code\"],\"properties\":{\"name\":{\"type\":\"string\",\"minLength\":1,\"maxLength\":255},\"script_code\":{\"type\":\"string\",\"pattern\":\"^[A-Z][a-z]{3}$\"}},\"additionalProperties\":false}}},\"additionalProperties\":false}},\"additionalProperties\":false}',`names`)", name: "chk_tag_versions_names_schema"
   end
 
   create_table "tags", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -631,8 +472,10 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.integer "post_count", default: 0, null: false
+    t.datetime "discarded_at"
     t.integer "version_no", null: false
     t.index ["deprecated_at"], name: "index_tags_on_deprecated_at"
+    t.index ["discarded_at"], name: "index_tags_on_discarded_at"
     t.index ["tag_name_id"], name: "index_tags_on_tag_name_id", unique: true
     t.check_constraint "(`deprecated_at` is null) or (`category` <> _utf8mb4'nico')", name: "chk_tags_deprecated_at_not_nico"
     t.check_constraint "`version_no` > 0", name: "chk_tags_version_no_positive"
@@ -789,6 +632,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.datetime "discarded_at"
+    t.integer "next_asset_no", default: 1, null: false
     t.integer "version_no", null: false
     t.index ["created_user_id"], name: "index_wiki_pages_on_created_user_id"
     t.index ["discarded_at"], name: "index_wiki_pages_on_discarded_at"
@@ -857,9 +701,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
   add_foreign_key "gekanator_question_suggestions", "users"
   add_foreign_key "gekanator_questions", "gekanator_question_suggestions"
   add_foreign_key "gekanator_questions", "users", column: "created_by_id"
-  add_foreign_key "locales", "languages", column: "language_code", primary_key: "code"
-  add_foreign_key "locales", "regions", column: "region_code", primary_key: "code"
-  add_foreign_key "locales", "scripts", column: "script_code", primary_key: "code"
   add_foreign_key "material_export_items", "materials"
   add_foreign_key "material_export_items", "users", column: "created_by_user_id"
   add_foreign_key "material_import_blocks", "users", column: "created_by_user_id"
@@ -868,57 +709,37 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
   add_foreign_key "material_sync_suppressions", "users", column: "created_by_user_id"
   add_foreign_key "material_versions", "materials"
   add_foreign_key "material_versions", "materials", column: "parent_id"
+  add_foreign_key "material_versions", "tags"
   add_foreign_key "material_versions", "users", column: "created_by_user_id"
   add_foreign_key "material_versions", "users", column: "updated_by_user_id"
   add_foreign_key "materials", "materials", column: "parent_id"
   add_foreign_key "materials", "tags"
   add_foreign_key "materials", "users", column: "created_by_user_id"
   add_foreign_key "materials", "users", column: "updated_by_user_id"
-  add_foreign_key "nico_tag_relations", "external_tags", column: "nico_tag_id"
   add_foreign_key "nico_tag_relations", "tags"
+  add_foreign_key "nico_tag_relations", "tags", column: "nico_tag_id"
+  add_foreign_key "nico_tag_versions", "tags"
   add_foreign_key "nico_tag_versions", "users", column: "created_by_user_id"
-  add_foreign_key "post_external_tags", "external_tags"
-  add_foreign_key "post_external_tags", "posts"
   add_foreign_key "post_implications", "posts"
   add_foreign_key "post_implications", "posts", column: "parent_post_id"
   add_foreign_key "post_similarities", "posts"
   add_foreign_key "post_similarities", "posts", column: "target_post_id"
-  add_foreign_key "post_tag_sections", "post_tags", column: ["post_id", "tag_id"], primary_key: ["post_id", "tag_id"], on_delete: :cascade
+  add_foreign_key "post_tag_sections", "posts"
+  add_foreign_key "post_tag_sections", "tags"
   add_foreign_key "post_tags", "posts"
   add_foreign_key "post_tags", "tags"
   add_foreign_key "post_tags", "users", column: "created_user_id"
+  add_foreign_key "post_tags", "users", column: "deleted_user_id"
   add_foreign_key "post_versions", "posts"
   add_foreign_key "post_versions", "users", column: "created_by_user_id"
   add_foreign_key "posts", "users", column: "uploaded_user_id"
   add_foreign_key "settings", "users"
-  add_foreign_key "tag_description_versions", "tag_description_versions", column: ["tag_id", "source_language_code", "source_version_no"], primary_key: ["tag_id", "language_code", "version_no"]
-  add_foreign_key "tag_descriptions", "languages", column: "language_code", primary_key: "code"
-  add_foreign_key "tag_descriptions", "tag_description_versions", column: ["tag_id", "source_language_code", "source_version_no"], primary_key: ["tag_id", "language_code", "version_no"]
-  add_foreign_key "tag_descriptions", "tags"
-  add_foreign_key "tag_descriptions", "users", column: "created_by_user_id"
-  add_foreign_key "tag_descriptions", "users", column: "updated_by_user_id"
-  add_foreign_key "tag_group_groups", "tag_groups"
-  add_foreign_key "tag_group_groups", "tag_groups", column: "child_tag_group_id"
-  add_foreign_key "tag_group_groups", "users", column: "created_by_user_id"
-  add_foreign_key "tag_group_placements", "tag_group_groups", column: ["tag_group_id", "child_tag_group_id"], primary_key: ["tag_group_id", "child_tag_group_id"]
-  add_foreign_key "tag_group_placements", "tag_group_placements", column: ["tag_group_id", "parent_position"], primary_key: ["tag_group_id", "position"]
-  add_foreign_key "tag_group_placements", "tag_group_tags", column: ["tag_group_id", "tag_id"], primary_key: ["tag_group_id", "tag_id"]
-  add_foreign_key "tag_group_placements", "tag_groups"
-  add_foreign_key "tag_group_placements", "users", column: "created_by_user_id"
-  add_foreign_key "tag_group_placements", "users", column: "updated_by_user_id"
-  add_foreign_key "tag_group_tags", "tag_groups"
-  add_foreign_key "tag_group_tags", "tags"
-  add_foreign_key "tag_group_tags", "users", column: "created_by_user_id"
-  add_foreign_key "tag_groups", "users", column: "created_by_user_id"
-  add_foreign_key "tag_groups", "users", column: "updated_by_user_id"
   add_foreign_key "tag_implications", "tags"
   add_foreign_key "tag_implications", "tags", column: "parent_tag_id"
-  add_foreign_key "tag_names", "languages", column: "language_code", primary_key: "code"
-  add_foreign_key "tag_names", "scripts", column: "script_code", primary_key: "code"
   add_foreign_key "tag_names", "tag_names", column: "canonical_id"
-  add_foreign_key "tag_names", "tags"
   add_foreign_key "tag_similarities", "tags"
   add_foreign_key "tag_similarities", "tags", column: "target_tag_id"
+  add_foreign_key "tag_versions", "tags"
   add_foreign_key "tag_versions", "users", column: "created_by_user_id"
   add_foreign_key "tags", "tag_names"
   add_foreign_key "theatre_comments", "theatres"
@@ -945,6 +766,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_08_010000) do
   add_foreign_key "user_post_views", "posts"
   add_foreign_key "user_post_views", "users"
   add_foreign_key "user_theme_slots", "users"
+  add_foreign_key "wiki_assets", "users", column: "created_by_user_id"
+  add_foreign_key "wiki_assets", "wiki_pages"
   add_foreign_key "wiki_pages", "tag_names"
   add_foreign_key "wiki_pages", "users", column: "created_user_id"
   add_foreign_key "wiki_pages", "users", column: "updated_user_id"

backend/lib/tasks/export_nico.rake

@@ -3,8 +3,8 @@ namespace :nico do
   task export: :environment do
     require 'open3'
 
-    mysql_user = ENV.fetch('NIZIKA_NICO_MYSQL_USER')
+    mysql_user = ENV.fetch('MYSQL_USER')
-    mysql_pass = ENV.fetch('NIZIKA_NICO_MYSQL_PASS')
+    mysql_pass = ENV.fetch('MYSQL_PASS')
     nizika_nico_path = ENV.fetch('NIZIKA_NICO_PATH')
 
     videos = Post.where('url LIKE ?', '%nicovideo.jp/watch/%').pluck(:url).filter_map {
@@ -14,7 +14,7 @@ namespace :nico do
     next if videos.empty?
 
     _, stderr, status = Open3.capture3(
-        { 'NIZIKA_NICO_MYSQL_USER' => mysql_user, 'NIZIKA_NICO_MYSQL_PASS' => mysql_pass },
+        { 'MYSQL_USER' => mysql_user, 'MYSQL_PASS' => mysql_pass },
         'python3', '-m', 'tracked_videos.put_bulk_upsert', *videos,
         chdir: nizika_nico_path)
 

backend/lib/tasks/migrate_help_pages.rake

@@ -1,44 +0,0 @@
-namespace :help do
-  desc 'ヘルプ移行'
-  task migrate: :environment do
-    help_path = ENV.fetch('BTRC_HUB_HELP_PATH')
-    abort if help_path.blank?
-
-    # 現状物理削除はなぃはず
-    pages = 
-        WikiPage
-        .joins(:tag_name)
-        .where(tag_names: { tag_id: nil })
-        .where.not("tag_names.name LIKE 'タググループ:%'")
-
-    pages.find_each do |page|
-      puts page.body
-      puts page.title
-
-      puts 'この identifier は何にする?'
-      identifier = $stdin.gets.chomp
-      Dir.mkdir "#{ help_path }/#{ identifier }"
-      Dir.mkdir "#{ help_path }/#{ identifier }/editions"
-      Dir.mkdir "#{ help_path }/#{ identifier }/editions/ja"
-
-      last_file_name = ''
-      WikiVersion.where(wiki_page_id: page.id).order(:version_no).each do |ver|
-        last_file_name, last_file_name_no = last_file_name.split('.')
-
-        file_name = ver.created_at.strftime('%Y-%m-%d')
-        if file_name == last_file_name
-          file_name += ".#{ (last_file_name_no || 1).to_i + 1 }"
-        end
-
-        File.write "#{ help_path }/#{ identifier }/editions/ja/#{ file_name }.mdx", ver.body
-
-        last_file_name = file_name
-      end
-
-      article_meta = { 'identifier' => identifier,
-                       'canonical_language' => 'ja',
-                       'languages' => { 'ja' => { 'current_edition' => last_file_name } } }
-      File.write "#{ help_path }/#{ identifier }/article.yml", article_meta.to_yaml
-    end
-  end
-end

backend/lib/tasks/sync_nico.rake

@@ -16,7 +16,7 @@ namespace :nico do
     end
 
     def sync_post_tags! post, desired_tag_ids, current_tag_ids: nil
-      current_tag_ids ||= PostTag.where(post_id: post.id).pluck(:tag_id).to_set
+      current_tag_ids ||= PostTag.kept.where(post_id: post.id).pluck(:tag_id).to_set
       desired_tag_ids = desired_tag_ids.compact.to_set
 
       to_add = desired_tag_ids - current_tag_ids
@@ -30,35 +30,16 @@ namespace :nico do
         end
       end
 
-      PostTag.where(post_id: post.id, tag_id: to_remove.to_a).find_each(&:destroy!)
+      PostTag.where(post_id: post.id, tag_id: to_remove.to_a).kept.find_each do |pt|
-    end
+        pt.discard_by!(nil)
-
-    def sync_post_external_tags! post, desired_external_tag_ids, current_external_tag_ids: nil
-      current_external_tag_ids ||=
-          PostExternalTag.where(post_id: post.id).pluck(:external_tag_id).to_set
-      desired_external_tag_ids = desired_external_tag_ids.compact.to_set
-
-      to_add = desired_external_tag_ids - current_external_tag_ids
-      to_remove = current_external_tag_ids - desired_external_tag_ids
-
-      ExternalTag.where(id: to_add.to_a).find_each do |external_tag|
-        begin
-          PostExternalTag.create!(post:, external_tag:)
-        rescue ActiveRecord::RecordNotUnique
-          ;
       end
     end
 
-      PostExternalTag
+    mysql_user = ENV['MYSQL_USER']
-          .where(post_id: post.id, external_tag_id: to_remove.to_a)
+    mysql_pass = ENV['MYSQL_PASS']
-          .find_each(&:destroy!)
-    end
-
-    mysql_user = ENV['NIZIKA_NICO_MYSQL_USER']
-    mysql_pass = ENV['NIZIKA_NICO_MYSQL_PASS']
     nizika_nico_path = ENV['NIZIKA_NICO_PATH']
     stdout, stderr, status = Open3.capture3(
-        { 'NIZIKA_NICO_MYSQL_USER' => mysql_user, 'NIZIKA_NICO_MYSQL_PASS' => mysql_pass },
+        { 'MYSQL_USER' => mysql_user, 'MYSQL_PASS' => mysql_pass },
         'python3', "#{ nizika_nico_path }/get_videos.py")
 
     unless status.success?
@@ -130,64 +111,58 @@ namespace :nico do
         sync_post_tags!(post, [Tag.tagme.id, Tag.bot.id, Tag.niconico.id, Tag.video.id])
       end
 
+      tags = post.tags
       # 既存のタグ Id. 集合
-      kept_tag_ids = post.tags.pluck(:id).to_set
+      kept_tag_ids = tags.pluck(:id).to_set
-
+      # うち内部タグ Id. 集合
-      # 既存の外部タグ Id. 集合
+      kept_non_nico_tag_ids = tags.not_nico.pluck(:id).to_set
-      kept_external_tag_ids = post.external_tags.nico.pluck(:id).to_set
-
-      # 記載すべき外部タグ Id. のリスト
-      desired_external_tag_ids = []
 
+      # 記載すべき外部タグ Id. および連携される内部タグ Id. のリスト
+      desired_nico_tag_based_ids = []
       # 記載すべき内部タグ Id. のリスト
-      desired_tag_ids = kept_tag_ids.to_a
+      desired_non_nico_tag_ids = []
 
       datum['tags'].each do |raw|
-        name = TagNameSanitisationRule.sanitise("nico:#{ raw }").delete_prefix('nico:')
+        name = TagNameSanitisationRule.sanitise("nico:#{ raw }")
-        tag = ExternalTag.find_or_create_by!(platform: :nico, name:)
+        tag = Tag.find_or_create_by_tag_name!(name, category: :nico)
 
-        unless tag.nico_tag_versions.exists?
+        event_type = tag.nico_tag_versions.exists? ? :update : :create
-          NicoTagVersionRecorder.record!(external_tag: tag,
+        NicoTagVersionRecorder.record!(tag:, event_type:, created_by_user: nil)
-                                         event_type: :create,
-                                         created_by_user: nil)
-        end
 
-        desired_external_tag_ids << tag.id
+        desired_nico_tag_based_ids << tag.id
 
         # 新たに記載される外部タグと連携される内部タグを記載
-        # 連携タグは記載すれども消除せず．
+        unless tag.id.in?(kept_tag_ids)
-        unless tag.id.in?(kept_external_tag_ids)
+          linked_ids = tag.linked_tags.pluck(:id)
-          desired_tag_ids.concat(tag.linked_tags.pluck(:id))
+          desired_non_nico_tag_ids.concat(linked_ids)
+          desired_nico_tag_based_ids.concat(linked_ids)
         end
       end
 
       deerjikist = Deerjikist.find_by(platform: :nico, code: datum['user'])
       if deerjikist
-        desired_tag_ids << deerjikist.tag_id
+        desired_non_nico_tag_ids << deerjikist.tag_id
-      elsif !(Tag.where(id: kept_tag_ids).where(category: :deerjikist).exists?)
+        desired_nico_tag_based_ids << deerjikist.tag_id
-        desired_tag_ids << Tag.no_deerjikist.id
+      elsif !(Tag.where(id: kept_non_nico_tag_ids).where(category: :deerjikist).exists?)
+        desired_non_nico_tag_ids << Tag.no_deerjikist.id
+        desired_nico_tag_based_ids << Tag.no_deerjikist.id
       end
 
-      desired_external_tag_ids.uniq!
+      desired_nico_tag_based_ids.uniq!
-      desired_tag_ids.uniq!
 
-      # 外部タグの記載に際しては “bot 操作” タグを記載しなぃ．
+      desired_all_tag_ids = kept_non_nico_tag_ids.to_a + desired_nico_tag_based_ids
-      if kept_tag_ids != desired_tag_ids.to_set
+      desired_non_nico_tag_ids.concat(kept_non_nico_tag_ids.to_a)
-        desired_tag_ids << Tag.bot.id
+      desired_non_nico_tag_ids.uniq!
-        desired_tag_ids.uniq!
+      if kept_non_nico_tag_ids != desired_non_nico_tag_ids.to_set
+        desired_all_tag_ids << Tag.bot.id
       end
+      desired_all_tag_ids.uniq!
 
-      tags_changed =
+      sync_post_tags!(post, desired_all_tag_ids, current_tag_ids: kept_tag_ids)
-          kept_tag_ids != desired_tag_ids.to_set ||
-          kept_external_tag_ids != desired_external_tag_ids.to_set
-
-      sync_post_tags!(post, desired_tag_ids, current_tag_ids: kept_tag_ids)
-      sync_post_external_tags!(post, desired_external_tag_ids,
-                               current_external_tag_ids: kept_external_tag_ids)
 
       if post_created
         PostVersionRecorder.record!(post:, event_type: :create, created_by_user: nil)
-      elsif post_changed || tags_changed
+      elsif post_changed || kept_tag_ids != desired_all_tag_ids.to_set
         PostVersionRecorder.ensure_snapshot!(post, created_by_user: nil)
         PostVersionRecorder.record!(post:, event_type: :update, created_by_user: nil)
       end

backend/spec/db/delete_discarded_tags_spec.rb

@@ -1,124 +0,0 @@
-require 'rails_helper'
-require_relative '../../db/migrate/20260921020000_delete_discarded_records_from_tags'
-require_relative '../../db/migrate/20260921030000_delete_discarded_records_from_tag_names'
-
-RSpec.describe 'discarded tag cleanup migrations' do
-  [DeleteDiscardedRecordsFromTags, DeleteDiscardedRecordsFromTagNames].each do |migration_class|
-    it "rejects rollback of #{ migration_class.name }" do
-      expect { migration_class.new.down }
-          .to raise_error(ActiveRecord::IrreversibleMigration)
-    end
-  end
-
-  context 'with legacy records' do
-    # Reproduce the historical schema required by these pre-multilingual migrations.
-    self.use_transactional_tests = false
-
-    before do
-      record_class = Class.new(ActiveRecord::Base) do
-        self.abstract_class = true
-      end
-      stub_const('TagCleanupMigrationRecord', record_class)
-      config = ActiveRecord::Base.connection_db_config.configuration_hash
-      @database = "btrc_hub_test_tag_cleanup_#{ Process.pid }_#{ SecureRandom.hex(4) }"
-      record_class.establish_connection(config.merge(database: nil))
-      @connection = record_class.lease_connection
-      @connection.create_database(@database)
-      @database_created = true
-      @connection.execute("USE #{ @connection.quote_table_name(@database) }")
-    end
-
-    after do
-      @connection.drop_database(@database) if @database_created
-    ensure
-      TagCleanupMigrationRecord.remove_connection
-    end
-
-    before do
-      @connection.create_table(:tag_names) do |t|
-        t.string :name, null: false, index: { unique: true }
-        t.bigint :canonical_id
-        t.datetime :discarded_at, index: true
-      end
-      @connection.add_foreign_key(:tag_names, :tag_names, column: :canonical_id)
-      @connection.create_table(:tags) do |t|
-        t.references :tag_name, null: false, foreign_key: true, index: { unique: true }
-        t.datetime :discarded_at, index: true
-      end
-      @connection.create_table(:nico_tag_relations) do |t|
-        t.references :tag, null: false, foreign_key: true
-        t.references :nico_tag, null: false, foreign_key: { to_table: :tags }
-      end
-      @connection.create_table(:tag_implications) do |t|
-        t.references :tag, null: false, foreign_key: true
-        t.references :parent_tag, null: false, foreign_key: { to_table: :tags }
-      end
-      [:tag_versions, :nico_tag_versions, :material_versions].each do |table|
-        @connection.create_table(table) do |t|
-          t.references :tag, null: false, foreign_key: true
-        end
-      end
-
-      @connection.execute(<<~SQL)
-        INSERT INTO tag_names (id, name, canonical_id, discarded_at) VALUES
-          (1, 'kept', NULL, NULL),
-          (2, 'merged_alias', 1, NULL),
-          (3, 'nico:deleted', NULL, '2026-09-20'),
-          (4, 'nico:kept', NULL, NULL),
-          (5, 'deleted_name', NULL, '2026-09-20')
-      SQL
-      @connection.execute(<<~SQL)
-        INSERT INTO tags (id, tag_name_id, discarded_at) VALUES
-          (1, 1, NULL), (2, 2, '2026-09-20'),
-          (3, 3, '2026-09-20'), (4, 4, NULL)
-      SQL
-      @connection.execute(<<~SQL)
-        INSERT INTO nico_tag_relations (id, tag_id, nico_tag_id) VALUES
-          (1, 1, 4), (2, 2, 4), (3, 1, 3), (4, 2, 3)
-      SQL
-      @connection.execute(<<~SQL)
-        INSERT INTO tag_implications (id, tag_id, parent_tag_id) VALUES
-          (1, 1, 4), (2, 2, 1), (3, 1, 2), (4, 2, 3)
-      SQL
-      @connection.execute('INSERT INTO tag_versions (tag_id) VALUES (1), (2)')
-      @connection.execute('INSERT INTO nico_tag_versions (tag_id) VALUES (3), (4)')
-      @connection.execute('INSERT INTO material_versions (tag_id) VALUES (1), (2)')
-    end
-
-    it 'removes discarded records and their links while retaining aliases and history' do
-      [DeleteDiscardedRecordsFromTags, DeleteDiscardedRecordsFromTagNames].each do |klass|
-        migration = klass.new
-        allow(migration).to receive(:connection).and_return(@connection)
-        migration.suppress_messages { migration.up }
-      end
-
-      expect(@connection.select_values('SELECT id FROM tags ORDER BY id')).to eq([1, 4])
-      expect(@connection.select_rows('SELECT id, canonical_id FROM tag_names ORDER BY id'))
-          .to eq([[1, nil], [2, 1], [4, nil]])
-      expect(@connection.select_values('SELECT id FROM nico_tag_relations')).to eq([1])
-      expect(@connection.select_values('SELECT id FROM tag_implications')).to eq([1])
-      expect(@connection.select_values('SELECT tag_id FROM tag_versions ORDER BY tag_id'))
-          .to eq([1, 2])
-      expect(@connection.select_values('SELECT tag_id FROM nico_tag_versions ORDER BY tag_id'))
-          .to eq([3, 4])
-      expect(@connection.select_values('SELECT tag_id FROM material_versions ORDER BY tag_id'))
-          .to eq([1, 2])
-
-      [:tags, :tag_names].each do |table|
-        expect(@connection.column_exists?(table, :discarded_at)).to be(false)
-        expect(@connection.index_exists?(table, :discarded_at)).to be(false)
-      end
-      [:tag_versions, :nico_tag_versions, :material_versions].each do |table|
-        expect(@connection.foreign_key_exists?(table, :tags, column: :tag_id)).to be(false)
-      end
-      expect(@connection.foreign_key_exists?(:tags, :tag_names)).to be(true)
-      expect(@connection.foreign_key_exists?(:tag_names, :tag_names, column: :canonical_id))
-          .to be(true)
-      expect(@connection.index_exists?(:tag_names, :name, unique: true)).to be(true)
-      expect(@connection.index_exists?(:tags, :tag_name_id, unique: true)).to be(true)
-      [:nico_tag_relations, :tag_implications].each do |table|
-        expect(@connection.foreign_keys(table).map(&:to_table)).to eq(['tags', 'tags'])
-      end
-    end
-  end
-end

backend/spec/db/external_tags_spec.rb

@@ -1,191 +0,0 @@
-require 'rails_helper'
-require_relative '../../db/migrate/20260921040000_create_external_tags'
-require_relative '../../db/migrate/20260921050000_create_post_external_tags'
-require_relative '../../db/migrate/20260921060000_change_foreign_key_on_nico_tag_relations'
-require_relative '../../db/migrate/20260921230000_migrate_external_tags'
-
-RSpec.describe 'external tag migrations' do
-  self.use_transactional_tests = false
-
-  before do
-    record_class = Class.new(ActiveRecord::Base) do
-      self.abstract_class = true
-    end
-    stub_const('ExternalTagMigrationRecord', record_class)
-    config = ActiveRecord::Base.connection_db_config.configuration_hash
-    @database = "btrc_hub_test_external_tags_#{ Process.pid }_#{ SecureRandom.hex(4) }"
-    record_class.establish_connection(config.merge(database: nil))
-    @connection = record_class.lease_connection
-    @connection.create_database(@database)
-    @database_created = true
-    @connection.execute("USE #{ @connection.quote_table_name(@database) }")
-    version_class = Class.new(record_class) do
-      self.table_name = 'post_versions'
-    end
-    stub_const('MigrateExternalTags::MigrationPostVersion', version_class)
-    create_legacy_tables
-    seed_legacy_records
-  end
-
-  after do
-    @connection.drop_database(@database) if @database_created
-  ensure
-    ExternalTagMigrationRecord.remove_connection
-  end
-
-  def migrate klass
-    migration = klass.new
-    allow(migration).to receive(:connection).and_return(@connection)
-    migration.suppress_messages { migration.migrate(:up) }
-  end
-
-  def create_legacy_tables
-    @connection.create_table(:tag_names) { |t| t.string :name }
-    @connection.create_table(:tags) do |t|
-      t.references :tag_name, foreign_key: true
-      t.string :category
-      t.integer :post_count
-      t.datetime :created_at
-    end
-    @connection.create_table(:posts)
-    @connection.create_table(:post_tags) do |t|
-      t.references :post, foreign_key: true
-      t.references :tag, foreign_key: true
-      t.datetime :created_at
-    end
-    @connection.create_table(:nico_tag_versions) do |t|
-      t.bigint :tag_id
-      t.integer :version_no
-      t.string :name
-      t.datetime :created_at
-    end
-    @connection.create_table(:nico_tag_relations) do |t|
-      t.references :tag, foreign_key: true
-      t.references :nico_tag, foreign_key: { to_table: :tags }
-    end
-    [:post_tag_sections, :materials, :theatre_skip_event_tags].each do |table|
-      @connection.create_table(table) { |t| t.references :tag, foreign_key: true }
-    end
-    @connection.create_table(:tag_implications) do |t|
-      t.references :tag, foreign_key: true
-      t.references :parent_tag, foreign_key: { to_table: :tags }
-    end
-    @connection.create_table(:tag_similarities) do |t|
-      t.references :tag, foreign_key: true
-      t.references :target_tag, foreign_key: { to_table: :tags }
-    end
-    @connection.create_table(:post_versions) { |t| t.json :tags_json, null: false }
-    @connection.add_check_constraint(:post_versions, 'JSON_VALID(tags_json)',
-                                     name: 'chk_post_versions_tags_json_schema')
-  end
-
-  def seed_legacy_records
-    @connection.execute(<<~SQL)
-      INSERT INTO tag_names (id, name) VALUES (1, 'internal'), (2, 'nico:raw tag[]');
-    SQL
-    @connection.execute(<<~SQL)
-      INSERT INTO tags (id, tag_name_id, category, post_count, created_at) VALUES
-        (1, 1, 'general', 1, '2026-09-01'), (2, 2, 'nico', 1, '2026-09-02')
-    SQL
-    @connection.execute('INSERT INTO posts (id) VALUES (1)')
-    @connection.execute(<<~SQL)
-      INSERT INTO post_tags (post_id, tag_id, created_at) VALUES
-        (1, 1, '2026-09-03'), (1, 2, '2026-09-04')
-    SQL
-    @connection.execute(<<~SQL)
-      INSERT INTO nico_tag_versions (tag_id, version_no, name, created_at) VALUES
-        (2, 1, 'nico:raw tag[]', '2026-09-02'),
-        (3, 1, 'nico:deleted', '2026-09-01'),
-        (3, 2, 'nico:deleted_later', '2026-09-02')
-    SQL
-    @connection.execute('INSERT INTO nico_tag_relations (tag_id, nico_tag_id) VALUES (1, 2)')
-    @connection.execute(<<~SQL)
-      INSERT INTO tag_similarities (tag_id, target_tag_id) VALUES (1, 1), (1, 2), (2, 1)
-    SQL
-    @connection.execute('INSERT INTO theatre_skip_event_tags (tag_id) VALUES (1), (2)')
-    @legacy_internal = { 'id' => 1, 'version_no' => 2,
-                         'name' => 'internal', 'category' => 'general',
-                         'sections' => [{ 'begin_ms' => 1000, 'end_ms' => nil }] }
-    snapshots = [@legacy_internal,
-                 { 'id' => 2, 'category' => 'nico' },
-                 { 'id' => 3, 'category' => 'nico' }]
-    @connection.execute(<<~SQL)
-      INSERT INTO post_versions (tags_json) VALUES
-        (#{ @connection.quote(snapshots.to_json) }), ('[]')
-    SQL
-  end
-
-  def prepare_external_tables
-    migrate(CreateExternalTags)
-    migrate(CreatePostExternalTags)
-    migrate(ChangeForeignKeyOnNicoTagRelations)
-  end
-
-  it 'preserves ids, raw names, counts, timestamps, post links and historical-only tags' do
-    prepare_external_tables
-
-    rows = @connection.select_rows(<<~SQL)
-      SELECT id, platform, name, post_count, DATE_FORMAT(created_at, '%Y-%m-%d')
-      FROM external_tags ORDER BY id
-    SQL
-    expect(rows).to eq([
-        [2, 'nico', 'raw tag[]', 1, '2026-09-02'],
-        [3, 'nico', 'deleted', 0, '2026-09-01']])
-    expect(@connection.select_rows(<<~SQL)).to eq([[1, 2, '2026-09-04']])
-      SELECT post_id, external_tag_id, DATE_FORMAT(created_at, '%Y-%m-%d')
-      FROM post_external_tags
-    SQL
-    expect(@connection.foreign_key_exists?(:nico_tag_relations, :external_tags,
-                                           column: :nico_tag_id)).to be(true)
-    expect(@connection.foreign_key_exists?(:nico_tag_relations, :tags,
-                                           column: :tag_id)).to be(true)
-  end
-
-  it 'converts snapshots and removes only obsolete internal rows and derived links' do
-    prepare_external_tables
-    migrate(MigrateExternalTags)
-
-    expect(@connection.select_values('SELECT id FROM tags')).to eq([1])
-    expect(@connection.select_values('SELECT id FROM tag_names')).to eq([1])
-    expect(@connection.select_values('SELECT tag_id FROM post_tags')).to eq([1])
-    expect(@connection.select_rows('SELECT tag_id, nico_tag_id FROM nico_tag_relations'))
-        .to eq([[1, 2]])
-    expect(@connection.select_rows('SELECT tag_id, target_tag_id FROM tag_similarities'))
-        .to eq([[1, 1]])
-    expect(@connection.select_values('SELECT tag_id FROM theatre_skip_event_tags')).to eq([1])
-    expect(@connection.select_value('SELECT COUNT(*) FROM nico_tag_versions')).to eq(3)
-    versions = MigrateExternalTags::MigrationPostVersion.order(:id)
-    expect(versions.first.tags_json).to eq([
-        @legacy_internal.except('id').merge('tag_id' => 1),
-        { 'external_tag_id' => 2 }, { 'external_tag_id' => 3 }])
-    expect(versions.last.tags_json).to eq([])
-
-    invalid_snapshots = [@legacy_internal,
-                         { 'external_tag_id' => 0 },
-                         { 'external_tag_id' => 2, 'tag_id' => 1 },
-                         { 'external_tag_id' => 2, 'name' => 'extra' },
-                         { 'tag_id' => 1, 'version_no' => 1 }]
-    invalid_snapshots.each do |snapshot|
-      expect {
-        MigrateExternalTags::MigrationPostVersion.create!(tags_json: [snapshot])
-      }.to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-    end
-    expect { MigrateExternalTags.new.down }
-        .to raise_error(ActiveRecord::IrreversibleMigration)
-  end
-
-  { post_tag_sections: '(tag_id) VALUES (2)',
-    materials: '(tag_id) VALUES (2)',
-    tag_implications: '(tag_id, parent_tag_id) VALUES (1, 2)' }.each do |table, values|
-    it "aborts before deleting data when #{ table } references a legacy nico tag" do
-      prepare_external_tables
-      @connection.execute("INSERT INTO #{ table } #{ values }")
-
-      expect { migrate(MigrateExternalTags) }.to raise_error(RuntimeError, /#{ table }/)
-
-      expect(@connection.select_values('SELECT id FROM tags ORDER BY id')).to eq([1, 2])
-      expect(MigrateExternalTags::MigrationPostVersion.first.tags_json.first)
-          .to eq(@legacy_internal)
-    end
-  end
-end

backend/spec/db/tag_description_migration_spec.rb

@@ -1,34 +0,0 @@
-require 'rails_helper'
-require_relative '../../db/migrate/20261003010000_migrate_tag_descriptions_from_wiki_pages'
-
-RSpec.describe 'Tag description migration identity' do
-  it 'preserves every revision ID and repeated body in an independent sequence' do
-    user = create_member_user!
-    tag_name = create(:tag_name, name: 'description_migration')
-    page = Wiki::Commit.create_content!(
-        tag_name:, body: 'A', created_by_user: user)
-    revisions = [page.current_revision]
-    ['A', 'B', 'B', 'A'].each do |body|
-      revisions << Wiki::Commit.content!(
-          page:, body:, created_user: user, base_revision_id: revisions.last.id)
-    end
-    tag = create(:tag, primary_tag_name: tag_name)
-    legacy_state = [page.reload.attributes, revisions.map(&:attributes)]
-    expect(page.wiki_versions.count).to eq(3)
-
-    migration = MigrateTagDescriptionsFromWikiPages.new
-    migration.suppress_messages { migration.up }
-
-    versions = TagDescriptionVersion.where(tag_id: tag.id, language_code: 'ja')
-        .order(:version_no)
-    expect(versions.pluck(:id)).to eq(revisions.map(&:id))
-    expect(versions.pluck(:version_no)).to eq([1, 2, 3, 4, 5])
-    expect(versions.pluck(:body)).to eq(['A', 'A', 'B', 'B', 'A'])
-    expect(versions.pluck(:created_by_user_id)).to eq([user.id] * 5)
-    expect(versions.pluck(:created_at)).to eq(revisions.map(&:created_at))
-    expect(TagDescription.find(page.id)).to have_attributes(
-        tag_id: tag.id, language_code: 'ja', version_no: 5, body: 'A')
-    expect([page.reload.attributes, revisions.map { |revision| revision.reload.attributes }])
-        .to eq(legacy_state)
-  end
-end

backend/spec/db/tag_group_constraints_spec.rb

@@ -1,110 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe 'Tag group persistence constraints' do
-  include TagGroupRecords
-
-  let!(:user) { create_member_user! }
-  let!(:tag) { group_tag('制約確認') }
-  let!(:group_id) do
-    seed_group(
-        name: '制約確認',
-        members: [{ 'tag_id' => tag.id, 'version_no' => tag.version_no }])
-  end
-
-  def placement attributes
-    insert_group_row('tag_group_placements', {
-        tag_group_id: group_id, position: 1,
-        created_at: Time.current, updated_at: Time.current }.merge(attributes))
-  end
-
-  def reject_statement
-    before_state = group_state
-    expect { yield }.to raise_error(ActiveRecord::StatementInvalid)
-    expect(group_state).to eq(before_state)
-  end
-
-  it 'allows membership without placement' do
-    expect(group_rows('tag_group_tags', tag_group_id: group_id).size).to eq(1)
-    expect(group_rows('tag_group_placements', tag_group_id: group_id)).to be_empty
-  end
-
-  it 'allows repeated Tag placements with unique membership' do
-    placement(tag_id: tag.id)
-    placement(tag_id: tag.id, position: 2)
-    expect(group_rows('tag_group_tags', tag_group_id: group_id).size).to eq(1)
-    expect(group_rows('tag_group_placements', tag_group_id: group_id).size).to eq(2)
-  end
-
-  it 'rejects duplicate Tag membership' do
-    reject_statement do
-      insert_group_row('tag_group_tags', {
-          tag_group_id: group_id, tag_id: tag.id, created_at: Time.current })
-    end
-  end
-
-  it 'rejects duplicate child membership' do
-    child_id = seed_group(name: '子')
-    attributes = { tag_group_id: group_id, child_tag_group_id: child_id,
-                   created_at: Time.current }
-    insert_group_row('tag_group_groups', attributes)
-    reject_statement { insert_group_row('tag_group_groups', attributes) }
-  end
-
-  it 'rejects direct self membership' do
-    reject_statement do
-      insert_group_row('tag_group_groups', {
-          tag_group_id: group_id, child_tag_group_id: group_id, created_at: Time.current })
-    end
-  end
-
-  it 'rejects a placement without a kind' do
-    reject_statement { placement({ }) }
-  end
-
-  it 'rejects simultaneous Section and Tag kinds' do
-    reject_statement { placement(section_name: '区分', tag_id: tag.id) }
-  end
-
-  it 'rejects a description attached to a Tag placement' do
-    reject_statement { placement(tag_id: tag.id, description: '不正') }
-  end
-
-  it 'allows an optional description on a Section' do
-    placement(section_name: '区分', description: '説明')
-    expect(group_rows('tag_group_placements', tag_group_id: group_id).sole)
-        .to include('section_name' => '区分', 'description' => '説明')
-  end
-
-  it 'rejects a Tag placement absent from membership' do
-    other = group_tag('非メンバー')
-    reject_statement { placement(tag_id: other.id) }
-  end
-
-  it 'rejects a missing parent placement' do
-    reject_statement { placement(section_name: '子', parent_position: 9) }
-  end
-
-  it 'rejects a child ordered before its parent' do
-    placement(section_name: '親', position: 2)
-    reject_statement { placement(section_name: '子', position: 1, parent_position: 2) }
-  end
-
-  it 'rejects duplicate group names' do
-    reject_statement { seed_group(name: '制約確認') }
-  end
-
-  it 'rejects a missing mandatory group name' do
-    reject_statement { seed_group(name: nil) }
-  end
-
-  it 'rejects a six-level snapshot' do
-    nodes = []
-    6.times { nodes = [{ 'tag_id' => tag.id, 'children' => nodes }] }
-    reject_statement do
-      insert_group_row('tag_group_versions', {
-          tag_group_id: group_id, version_no: 2, event_type: 'update', name: '制約確認',
-          members: [{ 'tag_id' => tag.id, 'version_no' => tag.version_no }].to_json,
-          placements: nodes.to_json, created_at: Time.current })
-    end
-  end
-end

backend/spec/db/tag_group_migration_spec.rb

@@ -1,119 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe 'Tag group migration identity and structure' do
-  include TagGroupRecords
-
-  let!(:user) { create_member_user! }
-
-  before { I18n.locale = :ja }
-
-  it 'preserves page and revision IDs, timestamps and repeated historical structures' do
-    tag = group_tag('洗澡鹿')
-    body = "説明文\n\n- 洗澡鹿\n- 洗澡鹿"
-    page = legacy_group('伊地知ニジカ亜種', body)
-    revisions = [page.current_revision]
-    [body, '# 空の区分', body].each do |text|
-      revisions << Wiki::Commit.legacy_content!(page:, body: text, created_user: user)
-    end
-    before_state = group_state.except(*TagGroupRecords::GROUP_TABLES)
-
-    migrate_groups
-
-    versions = group_rows('tag_group_versions', tag_group_id: page.id)
-        .sort_by { _1.fetch('version_no') }
-    expect(versions.map { _1.fetch('id') }).to eq(revisions.map(&:id))
-    expect(versions.map { _1.fetch('version_no') }).to eq([1, 2, 3, 4])
-    expect(versions.map { _1.fetch('created_at') }).to eq(revisions.map(&:created_at))
-    expect(versions.map { _1.fetch('created_by_user_id') }).to eq([user.id] * 4)
-    expect(versions.map { _1.fetch('event_type') }).to eq(['create', 'update', 'update', 'update'])
-    expect(group_version(page.id, 1).fetch('placements')).to eq(
-        group_version(page.id, 2).fetch('placements'))
-    expect(group_version(page.id, 3).fetch('placements')).to eq([
-        { 'section_name' => '空の区分', 'description' => nil, 'children' => [] }])
-    expect_group_snapshot(
-        page.id, number: 4, description: '説明文',
-        members: [{ 'tag_id' => tag.id, 'version_no' => tag.version_no }],
-        placements: [{ 'tag_id' => tag.id, 'children' => [] }] * 2)
-    expect(group_rows('tag_groups', id: page.id).sole).to include(
-        'created_at' => page.created_at, 'updated_at' => page.reload.updated_at)
-    expect(group_state.except(*TagGroupRecords::GROUP_TABLES)).to eq(before_state)
-  end
-
-  it 'migrates nested list Sections and child groups as different placement kinds' do
-    series = group_tag('ぼざろクリーチャーシリーズ')
-    deer = group_tag('洗澡鹿')
-    nijika = group_tag('伊地知ニジカ')
-    child = legacy_group('伊地知ニジカ亜種', <<~MARKDOWN)
-      - ぼざろクリーチャーシリーズ
-        - 伊地知ニジカ亜種:
-          - 洗澡鹿
-    MARKDOWN
-    parent = legacy_group('ぼざろクリーチャーシリーズのキャラクター', <<~MARKDOWN)
-      - ぼざろクリーチャーシリーズ
-        - 伊地知ニジカ
-          - タググループ:伊地知ニジカ亜種
-    MARKDOWN
-
-    migrate_groups
-
-    expect_group_snapshot(
-        child.id, number: 1,
-        members: [series, deer].map { { 'tag_id' => _1.id, 'version_no' => _1.version_no } },
-        placements: [{ 'tag_id' => series.id, 'children' => [
-            { 'section_name' => '伊地知ニジカ亜種', 'description' => nil,
-              'children' => [{ 'tag_id' => deer.id, 'children' => [] }] }] }])
-    expect_group_snapshot(
-        parent.id, number: 1,
-        members: [
-            { 'tag_id' => series.id, 'version_no' => series.version_no },
-            { 'tag_id' => nijika.id, 'version_no' => nijika.version_no },
-            { 'tag_group_id' => child.id, 'version_no' => 1 }],
-        placements: [{ 'tag_id' => series.id, 'children' => [
-            { 'tag_id' => nijika.id, 'children' => [
-                { 'tag_group_id' => child.id, 'children' => [] }] }] }])
-  end
-
-  it 'preserves heading order, group paragraphs and Section descriptions' do
-    names = ['タグ希望', 'キャラクター名希望', '楽曲情報希望', 'bot操作', 'ニジラー情報不詳']
-    tags = names.map { group_tag(_1) }
-    markdown = <<~MARKDOWN
-      全体の説明
-
-      # 要求
-      要求の説明
-
-      - タグ希望
-        - キャラクター名希望
-        - 楽曲情報希望
-
-      # 情報
-      - bot操作
-      - ニジラー情報不詳
-    MARKDOWN
-    page = legacy_group('メタタグ', markdown)
-    expect(page.current_revision.body).to eq(markdown.chomp)
-
-    migrate_groups
-
-    leaves = tags.map { { 'tag_id' => _1.id, 'children' => [] } }
-    leaves.first['children'] = leaves[1..2]
-    expect_group_snapshot(
-        page.id, number: 1, description: '全体の説明',
-        members: tags.map { { 'tag_id' => _1.id, 'version_no' => _1.version_no } },
-        placements: [
-            { 'section_name' => '要求', 'description' => '要求の説明',
-              'children' => [leaves.first] },
-            { 'section_name' => '情報', 'description' => nil,
-              'children' => leaves[3..4] }])
-  end
-
-  it 'leaves Help in the legacy domain' do
-    page = Wiki::Commit.create_legacy_content!(
-        tag_name: create(:tag_name, name: 'Help:移行対象外'),
-        body: 'Help 本文', created_by_user: user)
-    before_state = group_state
-    migrate_groups
-    expect(group_state).to eq(before_state)
-    expect(page.reload.body).to eq('Help 本文')
-  end
-end

backend/spec/db/tag_name_constraints_spec.rb

@@ -1,36 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe 'TagName database invariants' do
-  def insert_name!(**attributes)
-    TagName.insert_all!([{ name: 'constraint_name', language_code: 'ja',
-                          script_code: 'Jpan', primary_flg: true,
-                          created_at: Time.current, updated_at: Time.current,
-                          **attributes }])
-  end
-
-  it 'defaults persisted names to human-confirmed provenance' do
-    insert_name!
-
-    expect(TagName.find_by!(name: 'constraint_name').auto_generated).to be(false)
-  end
-
-  [[true, true], [true, false], [false, false]].each do |primary_flg, auto_generated|
-    it "allows primary=#{ primary_flg }, auto_generated=#{ auto_generated }" do
-      expect { insert_name!(primary_flg:, auto_generated:) }
-          .to change(TagName, :count).by(1)
-    end
-  end
-
-  it 'rejects auto-generated aliases at the database boundary' do
-    expect { insert_name!(primary_flg: false, auto_generated: true) }
-        .to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-  end
-
-  it 'rejects a second primary for the same tag and language' do
-    tag = create(:tag)
-
-    expect { insert_name!(tag_id: tag.id, auto_generated: false) }
-        .to raise_error(ActiveRecord::RecordNotUnique)
-    expect(TagName.where(tag:, language_code: 'ja', primary_flg: true).count).to eq(1)
-  end
-end

backend/spec/db/tag_version_names_spec.rb

@@ -1,91 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe 'TagVersion names database constraint' do
-  let(:tag) { create(:tag) }
-  let(:names) do
-    { 'ja' => { 'name' => 'snapshot_name', 'script_code' => 'Jpan',
-                'auto_generated' => false, 'aliases' => [] } }
-  end
-  let(:alias_name) { { 'name' => 'snapshot_alias', 'script_code' => 'Jpan' } }
-
-  def insert_snapshot!(snapshot)
-    TagVersion.insert_all!([{ tag_id: tag.id, version_no: 1, event_type: 'create',
-                             name: 'snapshot_name', category: 'general',
-                             aliases: '', parent_tag_ids: '', names: snapshot,
-                             created_at: Time.current }])
-  end
-
-  it 'accepts grouped Nipponese names with an empty alias list' do
-    expect { insert_snapshot!(names) }.to change(TagVersion, :count).by(1)
-    expect(TagVersion.find_by!(tag_id: tag.id).names).to eq(names)
-  end
-
-  it 'accepts aliases containing only their name and script' do
-    names['ja']['aliases'] = [alias_name]
-
-    expect { insert_snapshot!(names) }.to change(TagVersion, :count).by(1)
-  end
-
-  it 'rejects a flat array root' do
-    expect { insert_snapshot!([names.fetch('ja')]) }
-        .to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-  end
-
-  it 'rejects an empty object root' do
-    expect { insert_snapshot!({ }) }
-        .to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-  end
-
-  it 'rejects a language entry that is not an object' do
-    expect { insert_snapshot!({ 'ja' => 'not an object' }) }
-        .to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-  end
-
-  ['name', 'script_code', 'auto_generated', 'aliases'].each do |field|
-    it "rejects a primary entry missing #{ field }" do
-      names['ja'].delete(field)
-
-      expect { insert_snapshot!(names) }
-          .to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-    end
-  end
-
-  it 'rejects an empty primary name' do
-    names['ja']['name'] = ''
-
-    expect { insert_snapshot!(names) }
-        .to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-  end
-
-  it 'rejects incorrect script casing' do
-    names['ja']['script_code'] = 'JPAN'
-
-    expect { insert_snapshot!(names) }
-        .to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-  end
-
-  ['unknown', 'primary_flg', 'language_code'].each do |field|
-    it "rejects the extra primary field #{ field }" do
-      names['ja'][field] = true
-
-      expect { insert_snapshot!(names) }
-          .to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-    end
-  end
-
-  ['unknown', 'primary_flg', 'auto_generated'].each do |field|
-    it "rejects the extra alias field #{ field }" do
-      names['ja']['aliases'] = [alias_name.merge(field => true)]
-
-      expect { insert_snapshot!(names) }
-          .to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-    end
-  end
-
-  it 'rejects duplicate alias objects' do
-    names['ja']['aliases'] = [alias_name, alias_name.deep_dup]
-
-    expect { insert_snapshot!(names) }
-        .to raise_error(ActiveRecord::StatementInvalid, /check constraint/i)
-  end
-end

backend/spec/factories/external_tags.rb

@@ -1,6 +0,0 @@
-FactoryBot.define do
-  factory :external_tag do
-    platform { :nico }
-    sequence(:name) { |n| "external_tag_#{ n }" }
-  end
-end

backend/spec/factories/tag_names.rb

@@ -1,13 +1,5 @@
 FactoryBot.define do
   factory :tag_name do
-    language_code { 'ja' }
+    name { "tag-#{SecureRandom.hex(4)}" }
-    script_code { 'Jpan' }
-    primary_flg { true }
-    auto_generated { false }
-    sequence(:name) { |number| "tag-#{ SecureRandom.hex(4) }-#{ number }" }
-
-    trait :alias do
-      primary_flg { false }
-    end
   end
 end

backend/spec/factories/tags.rb

@@ -1,40 +1,21 @@
 FactoryBot.define do
   factory :tag do
     transient do
-      primary_name { nil }
+      name { nil }
-      primary_tag_name do
-        attributes = primary_name.nil? ? { } : { name: primary_name }
-        build(:tag_name, **attributes)
-      end
     end
 
     category { :general }
     post_count { 0 }
+    association :tag_name
 
     after(:build) do |tag, evaluator|
-      evaluator.primary_tag_name.primary_flg = true
+      tag.name = evaluator.name if evaluator.name.present?
-      tag.tag_names.target << evaluator.primary_tag_name
     end
 
-    before(:create) do |tag, evaluator|
+    trait :nico do
-      evaluator.primary_tag_name.save!
+      category { :nico }
-      # Compatibility write only; ownership is established through tag_id below.
+      transient do
-      tag.tag_name_id = evaluator.primary_tag_name.id
+        name { "nico:#{ SecureRandom.hex(4) }" }
-    end
-
-    after(:create) do |tag, evaluator|
-      evaluator.primary_tag_name.update!(tag:, primary_flg: true)
-
-      Locale.where(deprecated_at: nil).order(:language_code, :created_at, :script_code).to_a
-          .uniq(&:language_code).each do |locale|
-        next if tag.tag_names.exists?(language_code: locale.language_code,
-                                      primary_flg: true)
-
-        create(:tag_name,
-            tag:, language_code: locale.language_code,
-            script_code: locale.script_code,
-            name: TagName.generate_name(locale, tag, evaluator.primary_tag_name),
-            primary_flg: true, auto_generated: true)
       end
     end
   end

backend/spec/models/external_tag_spec.rb

@@ -1,38 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe ExternalTag, type: :model do
-  it 'preserves names without internal tag sanitisation or TagName records' do
-    external = nil
-
-    expect {
-      external = described_class.create!(platform: :nico, name: 'raw tag[]')
-    }.not_to change(TagName, :count)
-
-    expect(external.reload.name).to eq('raw tag[]')
-  end
-
-  it 'deletes post associations without deleting posts or version history' do
-    external = create(:external_tag)
-    post = create(:post)
-    PostExternalTag.create!(post:, external_tag: external)
-    version = NicoTagVersionRecorder.record!(
-        external_tag: external, event_type: :create, created_by_user: nil)
-
-    external.destroy!
-
-    expect(PostExternalTag.where(external_tag_id: external.id)).to be_empty
-    expect(post.reload.external_tags).to be_empty
-    expect(version.reload.tag_id).to eq(external.id)
-  end
-
-  it 'deletes external links without deleting linked internal tags' do
-    external = create(:external_tag)
-    tag = create(:tag)
-    NicoTagRelation.create!(nico_tag: external, tag:)
-
-    external.destroy!
-
-    expect(NicoTagRelation.where(nico_tag_id: external.id)).to be_empty
-    expect(Tag.exists?(tag.id)).to be(true)
-  end
-end

backend/spec/models/language_spec.rb

@@ -1,32 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe Language, type: :model do
-  it 'accepts Nipponese as the current supported language' do
-    expect(described_class.find('ja')).to be_valid
-    expect(described_class.where(deprecated_at: nil).pluck(:code)).to eq(['ja'])
-  end
-
-  it 'accepts English when multilingual support is enabled' do
-    pending '日本語以外の Language 有効化は別課題で実装する'
-    expect { described_class.create!(code: 'en', name: 'English') }
-        .to change(described_class, :count).by(1)
-  end
-
-  it 'rejects an unsupported language code' do
-    expect {
-      described_class.create!(code: 'xx', name: 'Unsupported')
-    }.to raise_error { |error|
-      expect(error).to be_a(ArgumentError).or be_a(ActiveRecord::RecordInvalid)
-    }
-  end
-
-  ['en', 'fr'].each do |code|
-    it "does not register #{ code } as a currently supported language" do
-      expect {
-        described_class.create!(code:, name: 'Unsupported')
-      }.to raise_error { |error|
-        expect(error).to be_a(ArgumentError).or be_a(ActiveRecord::RecordInvalid)
-      }
-    end
-  end
-end