#55

backend/app/controllers/application_controller.rb

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

backend/app/controllers/materials_controller.rb

@@ -72,6 +72,7 @@ class MaterialsController < ApplicationController
     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)
@@ -89,7 +90,7 @@ class MaterialsController < ApplicationController
 
     begin
       Material.transaction do
-        tag = resolve_material_tag!(tag_name_raw)
+        tag = resolve_material_tag!(locale, tag_name_raw)
         material = Material.new(tag:, url:,
                                 created_by_user: current_user,
                                 updated_by_user: current_user)
@@ -236,10 +237,8 @@ class MaterialsController < ApplicationController
     nil
   end
 
-  def resolve_material_tag! tag_name_raw
+  def resolve_material_tag! locale, tag_name_raw
-    tag_name = TagName.find_or_create_by!(name: tag_name_raw)
+    Tag.find_or_create_by_tag_name!(locale, tag_name_raw, category: :material)
-    tag = tag_name.tag
-    tag || Tag.create!(tag_name:, category: :material)
   end
 
   def material_index_needs_tag_name? filters

backend/app/controllers/nico_tags_controller.rb

@@ -15,22 +15,23 @@ 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 " \
+           .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')
-    q = q.where('external_tags.name LIKE ?', "%#{ name }%") if name
+           .includes(:tag_name, tag_name: :wiki_page, linked_tags: { tag_name: :wiki_page })
+    q = q.where('tag_names.name LIKE ?', "%#{ name }%") if name
     if linked_tag
       linked_tag_ids =
-          Tag
+        Tag
-          .joins(:tag_name)
+        .joins(:tag_name)
-          .where('tag_names.name LIKE ?', "%#{ linked_tag }%")
+        .where('tag_names.name LIKE ?', "%#{ linked_tag }%")
-          .pluck(:id)
+        .pluck(:id)
       linked_nico_tag_ids = NicoTagRelation.where(tag_id: linked_tag_ids).pluck(:nico_tag_id)
       q = q.where(id: linked_nico_tag_ids)
     end
@@ -69,16 +70,23 @@ class NicoTagsController < ApplicationController
     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!(linked_tag_names, with_tagme: false,
+      linked_tags = Tag.normalise_tags!(locale, linked_tag_names,
-                                                          with_no_deerjikist: false)
+                                        with_tagme: false,
+                                        with_no_deerjikist: false)
+      if linked_tags.any? { |t| t.nico? }
+        raise Tag::NicoTagNormalisationError
+      end
 
       TagVersioning.record_tag_snapshots!(linked_tags, created_by_user: current_user)
 

backend/app/controllers/post_versions_controller.rb

@@ -27,8 +27,8 @@ class PostVersionsController < ApplicationController
                 'prev.original_created_before AS prev_original_created_before')
     q = q.where('post_versions.post_id = ?', post_id) if post_id
     if tag_id
-      q = q.where("JSON_CONTAINS(post_versions.tags_json, JSON_OBJECT('tag_id', #{ tag_id })) " +
+      q = q.where("JSON_CONTAINS(post_versions.tags_json, JSON_OBJECT('id', #{ tag_id })) " +
-                  "OR JSON_CONTAINS(prev.tags_json, JSON_OBJECT('tag_id', #{ tag_id }))")
+                  "OR JSON_CONTAINS(prev.tags_json, JSON_OBJECT('id', #{ tag_id }))")
     end
 
     count = q.except(:select, :order, :limit, :offset).count
@@ -113,18 +113,21 @@ class PostVersionsController < ApplicationController
     end
   end
 
-  def build_version_tags cur_tags, prev_tags
+  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)
+        if cur_tags.include?(name) && prev_tags.include?(name)
-            'context'
+          'context'
-          elsif cur_tags.include?(name)
+        elsif cur_tags.include?(name)
-            'added'
+          'added'
-          else
+        else
-            'removed'
+          'removed'
-          end
+        end
 
-      { name:, type: }
+      {
+        name:,
+        type:
+      }
     end
   end
 end

backend/app/controllers/posts_controller.rb

@@ -308,6 +308,7 @@ 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]
@@ -329,7 +330,8 @@ class PostsController < ApplicationController
         base_snapshot = post_snapshot_from_version(base_version)
         current_snapshot = post_snapshot_from_record(post)
       end
-      incoming_snapshot = post_incoming_snapshot(title:,
+      incoming_snapshot = post_incoming_snapshot(locale:,
+                                                 title:,
                                                  original_created_from:,
                                                  original_created_before:,
                                                  tag_names:,
@@ -358,7 +360,7 @@ class PostsController < ApplicationController
             end
           end
 
-      apply_post_snapshot!(post, snapshot_to_apply)
+      apply_post_snapshot!(locale, post, snapshot_to_apply)
     end
 
     return render json: conflict_json, status: :conflict if conflict_json
@@ -671,6 +673,7 @@ class PostsController < ApplicationController
     post
         .post_tags
         .joins(tag: :tag_name)
+        .merge(Tag.not_nico)
         .merge(Tag.where(deprecated_at: nil))
         .includes(:sections, tag: :tag_name)
         .order('tag_names.name')
@@ -684,11 +687,13 @@ class PostsController < ApplicationController
     end
   end
 
-  def post_incoming_snapshot title:, original_created_from:, original_created_before:,
+  def post_incoming_snapshot locale:, 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) => { tags:, sections: }
+                        with_tagme: 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:)
@@ -823,7 +828,7 @@ class PostsController < ApplicationController
     (added_by_current & removed_by_me).present? || (removed_by_current & added_by_me).present?
   end
 
-  def apply_post_snapshot! post, snapshot
+  def apply_post_snapshot! locale, post, snapshot
     PostVersionRecorder.ensure_snapshot!(post, created_by_user: current_user)
 
     post.update!(title: snapshot[:title],
@@ -831,12 +836,15 @@ class PostsController < ApplicationController
                  original_created_from: snapshot[:original_created_from],
                  original_created_before: snapshot[:original_created_before])
 
-    Tag.normalise_tags!(snapshot[:tag_names],
+    Tag.normalise_tags!(locale, snapshot[:tag_names],
                         with_tagme: false,
                         deny_deprecated: true,
-                        with_sections: true) => { tags:, sections: }
+                        with_sections: true) => { tags: editable_tags, sections: }
-    TagVersioning.record_tag_snapshots!(tags, created_by_user: current_user)
+    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/tags_controller.rb

@@ -100,14 +100,13 @@ class TagsController < ApplicationController
 
   def autocomplete
     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('name LIKE ?', prefix)
+        .where('name LIKE ?', "#{ q }%")
         .where.not(canonical_id: nil)
         .pluck(:canonical_id, :name)
 
@@ -119,57 +118,29 @@ class TagsController < ApplicationController
       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_name)
+              .where(deprecated_at: nil)
-        .includes(:tag_name, :materials, tag_name: :wiki_page)
-        .where(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 =
+    tags =
-        if with_nico
+        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'))
-        .limit(20)
-        .map { |tag|
-          TagRepr.base(tag).merge(matched_alias: matched_alias_by_tag_name_id[tag.tag_name_id])
-        }
 
-    return render json: internal_rows unless with_nico
+    render json: tags.map { |tag|
-
+      TagRepr.base(tag).merge(matched_alias: matched_alias_by_tag_name_id[tag.tag_name_id])
-    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 { |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 }
-        }
-
-    rows =
-        (internal_rows + external_rows)
-        .sort_by { |row| [-row['post_count'], row['name']] }
-        .first(20)
-
-    render json: rows
   end
 
   def show
@@ -307,11 +278,17 @@ class TagsController < ApplicationController
 
     return unless validate_tag_rename(tag, name)
 
+    locale = resolve_locale!
+
     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
 
@@ -333,7 +310,7 @@ class TagsController < ApplicationController
       alias_names.delete(name)
 
       update_aliases!(tag, alias_names)
-      update_parent_tags!(tag, parent_names)
+      update_parent_tags!(locale, tag, parent_names)
 
       tag.reload
 
@@ -359,9 +336,13 @@ class TagsController < ApplicationController
 
     tag = Tag.find(params[:id])
 
+    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
+
     return unless validate_tag_rename(tag, name)
 
-    if category.present? && category == 'nico'
+    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
 
@@ -568,6 +549,11 @@ class TagsController < ApplicationController
   end
 
   def record_tag_version! tag, event_type:, created_by_user:, name_changed: false, wiki_page: nil
+    if tag.nico?
+      NicoTagVersionRecorder.record!(tag:, event_type:, created_by_user:)
+      return
+    end
+
     TagVersionRecorder.record!(tag:, event_type:, created_by_user:)
 
     return unless name_changed
@@ -675,9 +661,11 @@ class TagsController < ApplicationController
     end
   end
 
-  def update_parent_tags! tag, parent_names
+  def update_parent_tags! locale, tag, parent_names
-    parent_tags = Tag.normalise_tags!(parent_names, with_tagme: false,
+    parent_tags = Tag.normalise_tags!(locale, parent_names,
-                                                    with_no_deerjikist: false)
+                                      with_tagme: false,
+                                      with_no_deerjikist: false,
+                                      deny_nico: true)
 
     old_parent_tags = tag.parents.to_a
 

backend/app/models/external_tag.rb

@@ -1,20 +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
-    linked_tags.joins(:tag_name).order('tag_names.name').pluck('tag_names.name')
-  end
-end

backend/app/models/language.rb

@@ -0,0 +1,3 @@
+class Language < ApplicationRecord
+  has_many :languages, class_name: 'Locale', foreign_key: :language_code
+end

backend/app/models/locale.rb

@@ -0,0 +1,24 @@
+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
+
+  def self.nipponese = Locale.find('ja')
+
+  private
+
+  def generate_tag_names!
+    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.name),
+                      script_code:,
+                      primary_flg: true,
+                      # TODO: 公証実装したら書く．
+                      # auto_generated: true,
+                      canonical_id: nil)
+    end
+  end
+end

backend/app/models/nico_tag_relation.rb

@@ -1,9 +1,6 @@
 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

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

@@ -92,9 +92,6 @@ class Post < ApplicationRecord
            inverse_of: :parent_post
   has_many :children, through: :child_post_implications, source: :post
 
-  has_many :post_external_tags, dependent: :delete_all
-  has_many :external_tags, through: :post_external_tags
-
   has_one_attached :thumbnail
 
   attribute :version_no, :integer, default: 1
@@ -153,27 +150,19 @@ class Post < ApplicationRecord
   end
 
   def snapshot_tags_json
-    tag_snapshots =
+    post_tags
-        post_tags
+        .joins(tag: :tag_name)
-            .joins(tag: :tag_name)
+        .includes(:sections, tag: :tag_name)
-            .includes(:sections, tag: :tag_name)
+        .order('tags.id')
-            .order('tags.id')
+        .map do |pt|
-            .map { |pt|
+      { 'id' => pt.tag.id,
-          { 'tag_id' => pt.tag.id,
+        'version_no' => pt.tag.version_no,
-            'version_no' => pt.tag.version_no,
+        'name' => pt.tag.name,
-            'name' => pt.tag.name,
+        'category' => pt.tag.category,
-            'category' => pt.tag.category,
+        'sections' => pt.sections.sort_by(&:begin_ms).map {
-            'sections' => pt.sections.sort_by(&:begin_ms).map {
+          { 'begin_ms' => _1.begin_ms, 'end_ms' => _1.end_ms }
-                            { '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
-end

backend/app/models/script.rb

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

backend/app/models/tag.rb

@@ -28,10 +28,11 @@ class Tag < ApplicationRecord
   has_many :post_tags, inverse_of: :tag
   has_many :posts, through: :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: :nico_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
@@ -49,7 +50,9 @@ 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
 
@@ -63,15 +66,17 @@ class Tag < ApplicationRecord
                   character:   'character',
                   general:     'general',
                   material:    'material',
+                  nico:        'nico',
                   meta:        'meta'
 
   validates :category, presence: true, inclusion: { in: Tag.categories.keys }
 
-  validate :tag_name_mustnt_start_with_nico
+  validate :nico_tag_name_must_start_with_nico
   validate :tag_name_must_be_canonical
   validate :category_must_be_deerjikist_with_deerjikists
+  validate :nico_tags_cannot_be_deprecated
 
-  def self.nico_tags = ExternalTag.where(platform: :nico)
+  scope :nico_tags, -> { nico }
 
   CATEGORY_PREFIXES = {
       'general:'    => :general,
@@ -97,18 +102,21 @@ class Tag < ApplicationRecord
 
   def has_deerjikists = deerjikists.loaded? ? deerjikists.any? : deerjikists.exists?
 
-  def self.tagme = find_or_create_by_tag_name!('タグ希望', category: :meta)
+  def self.tagme = find_or_create_by_tag_name!(Locale.nipponese, 'タグ希望', category: :meta)
-  def self.bot = find_or_create_by_tag_name!('bot操作', category: :meta)
+  def self.bot = find_or_create_by_tag_name!(Locale.nipponese, 'bot操作', category: :meta)
-  def self.no_deerjikist = find_or_create_by_tag_name!('ニジラー情報不詳', category: :meta)
+  def self.no_deerjikist =
-  def self.video = find_or_create_by_tag_name!('動画', category: :meta)
+      find_or_create_by_tag_name!(Locale.nipponese, 'ニジラー情報不詳', category: :meta)
-  def self.niconico = find_or_create_by_tag_name!('ニコニコ', category: :meta)
+  def self.video = find_or_create_by_tag_name!(Locale.nipponese, '動画', category: :meta)
-  def self.youtube = find_or_create_by_tag_name!('YouTube', category: :meta)
+  def self.niconico = find_or_create_by_tag_name!(Locale.nipponese, 'ニコニコ', category: :meta)
+  def self.youtube = find_or_create_by_tag_name!(Locale.nipponese, 'YouTube', category: :meta)
 
-  def self.normalise_tags! tag_names, with_tagme: true,
+  def self.normalise_tags! locale, tag_names,
-                                      with_no_deerjikist: true,
+                           with_tagme: true,
-                                      deny_deprecated: false,
+                           with_no_deerjikist: true,
-                                      with_sections: false
+                           deny_nico: true,
-    if tag_names.any? { |n| n.downcase.start_with?('nico:') }
+                           deny_deprecated: false,
+                           with_sections: false
+    if deny_nico && tag_names.any? { |n| n.downcase.start_with?('nico:') }
       raise NicoTagNormalisationError
     end
 
@@ -136,7 +144,7 @@ class Tag < ApplicationRecord
 
       name = TagName.canonicalise(name).first
 
-      find_or_create_by_tag_name!(name, category: (cat || :general)).tap do |tag|
+      find_or_create_by_tag_name!(locale, name, category: (cat || :general)).tap do |tag|
         if deny_deprecated && tag.deprecated?
           raise DeprecatedTagNormalisationError, [tag.name]
         end
@@ -224,13 +232,25 @@ class Tag < ApplicationRecord
     [left_end_ms, right_end_ms].max
   end
 
-  def self.find_or_create_by_tag_name! name, category:
+  def self.find_or_create_by_tag_name! locale, name, category:
-    tn = TagName.find_or_create_by!(name: name.to_s.strip)
+    language_code = locale.language_code
-    tn = tn.canonical if tn.canonical_id?
+    name = name.to_s.strip
 
-    Tag.find_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
+    if tag
+      tag.update!(tag_name_id: tn.id) if tag.tag_name_id != tn.id
+      return tag
+    end
+
+    tag = Tag.create!(tag_name: tn, category:)
+    tn.update!(tag:)
+
+    tag
   rescue ActiveRecord::RecordNotUnique
     retry
   end
@@ -268,8 +288,12 @@ class Tag < ApplicationRecord
         TagVersioning.record!(source_tag, event_type: :discard, created_by_user:)
         source_tag.destroy!
 
-        source_tag_name.update_columns(canonical_id: target_tag.tag_name_id,
+        if source_tag.nico?
-                                       updated_at: Time.current)
+          source_tag_name.destroy!
+        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
@@ -296,9 +320,11 @@ class Tag < ApplicationRecord
 
   private
 
-  def tag_name_mustnt_start_with_nico
+  def nico_tag_name_must_start_with_nico
-    if name.to_s.downcase.start_with?('nico:')
+    n = name.to_s
-      errors.add :name, 'タグの命名規則に反してゐます．'
+    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
 
@@ -339,4 +365,10 @@ class Tag < ApplicationRecord
 
     total_s * 1_000 + match[:ms].to_s.ljust(3, '0')[0, 3].to_i
   end
+
+  def nico_tags_cannot_be_deprecated
+    if nico? && deprecated_at.present?
+      errors.add :deprecated_at, 'ニコタグは廃止できません．'
+    end
+  end
 end

backend/app/models/tag_name.rb

@@ -1,5 +1,5 @@
 class TagName < ApplicationRecord
-  has_one :tag
+  belongs_to :tag, optional: true
   has_one :wiki_page
 
   belongs_to :canonical, class_name: 'TagName', optional: true
@@ -21,6 +21,12 @@ class TagName < ApplicationRecord
     names.map { |name| tns[name]&.canonical&.name || name }.uniq
   end
 
+  def self.generate_name locale, 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 canonical_must_be_canonical

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_create_plan.rb

@@ -20,22 +20,23 @@ class PostCreatePlan
     parent_post_ids = normalise_parent_post_ids
     validate_parent_post_ids!(parent_post_ids)
 
-    { url: @attributes[:url],
+    {
-      title: @attributes[:title].to_s,
+        url: @attributes[:url],
-      thumbnail_base: @attributes[:thumbnail_base].presence,
+        title: @attributes[:title].to_s,
-      original_created_from: @attributes[:original_created_from].presence,
+        thumbnail_base: @attributes[:thumbnail_base].presence,
-      original_created_before: @attributes[:original_created_before].presence,
+        original_created_from: @attributes[:original_created_from].presence,
-      tags: serialised_tags(direct_tag_specs, tag_sections),
+        original_created_before: @attributes[:original_created_before].presence,
-      display_tags: display_tags(direct_tag_specs, tag_sections),
+        tags: serialised_tags(direct_tag_specs, tag_sections),
-      duration: @attributes[:duration].to_s,
+        display_tags: display_tags(direct_tag_specs, tag_sections),
-      video_ms: video_ms,
+        duration: @attributes[:duration].to_s,
-      parent_post_ids: parent_post_ids.join(' '),
+        video_ms: video_ms,
-      direct_tag_specs: direct_tag_specs,
+        parent_post_ids: parent_post_ids.join(' '),
-      default_tag_specs: default_tag_specs,
+        direct_tag_specs: direct_tag_specs,
-      snapshot_tag_specs: snapshot_tag_specs,
+        default_tag_specs: default_tag_specs,
-      post_tag_specs: post_tag_specs,
+        snapshot_tag_specs: snapshot_tag_specs,
-      tag_sections: tag_sections,
+        post_tag_specs: post_tag_specs,
-      normalised_parent_post_ids: parent_post_ids }
+        tag_sections: tag_sections,
+        normalised_parent_post_ids: parent_post_ids }
   end
 
   private
@@ -49,6 +50,7 @@ class PostCreatePlan
     tag_names.each do |raw_name|
       tag_name, category, sections = parse_raw_tag_name(raw_name)
       existing_tag = existing_tags_by_name[tag_name]
+      raise Tag::NicoTagNormalisationError if existing_tag&.nico?
       raise Tag::DeprecatedTagNormalisationError, [existing_tag.name] if existing_tag&.deprecated?
 
       direct_tag_specs << {
@@ -137,14 +139,14 @@ class PostCreatePlan
         Tag.expand_parent_tags(existing_snapshot_tags)
            .reject(&:deprecated?)
            .map { |tag|
-             { name: tag.name,
+             {
-               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]]
@@ -153,7 +155,7 @@ 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

backend/app/services/post_creator.rb

@@ -9,7 +9,7 @@ class PostCreator
     @field_warnings = { }
   end
 
-  def create!
+  def create!(locale)
     thumbnail_attachment = prepare_thumbnail_attachment
     post = Post.new(title: @attributes[:title].presence,
                     url: @attributes[:url],
@@ -25,7 +25,7 @@ class PostCreator
       post_tags = planned_post_tags
       sections = planned_sections
       TagVersioning.record_tag_snapshots!(snapshot_tags, created_by_user: @actor)
-      post.video_ms = planned_video_ms
+      post.video_ms = planned_video_ms(locale)
       post.save!
       sync_post_tags!(post, post_tags, sections)
       sync_parent_posts!(post, planned_parent_post_ids)
@@ -53,15 +53,15 @@ class PostCreator
 
   def planned_parent_post_ids = planned_create_attributes[:normalised_parent_post_ids]
 
-  def planned_video_ms
+  def planned_video_ms locale
-    planned_create_attributes[:video_ms]
+    planned_create_attributes(locale)[:video_ms]
   end
 
-  def planned_create_attributes
+  def planned_create_attributes locale
     @planned_create_attributes ||= begin
       if @attributes.key?(:snapshot_tag_specs)
-        snapshot_tags = materialise_tags(@attributes[:snapshot_tag_specs] || [])
+        snapshot_tags = materialise_tags(locale, @attributes[:snapshot_tag_specs] || [])
-        post_tags = materialise_tags(@attributes[:post_tag_specs] || [])
+        post_tags = materialise_tags(locale, @attributes[:post_tag_specs] || [])
         {
             snapshot_tags: snapshot_tags,
             post_tags: post_tags,
@@ -92,13 +92,13 @@ class PostCreator
         video_ms: plan[:video_ms] }
   end
 
-  def materialise_tags specs
+  def materialise_tags locale, specs
     Array(specs).each_with_object({ }) do |spec, tags|
       name = spec[:name] || spec['name']
       category = spec[:category] || spec['category']
       next if name.blank? || category.blank?
 
-      tag = Tag.find_or_create_by_tag_name!(name, category:)
+      tag = Tag.find_or_create_by_tag_name!(locale, name, category:)
       tag.update!(category:) if tag.category.to_sym != category.to_sym
       tags[name] ||= tag
     end.values

backend/app/services/tag_versioning.rb

@@ -1,16 +1,32 @@
 class TagVersioning
   def self.record! tag, event_type:, created_by_user:
-    TagVersionRecorder.record!(tag:, event_type:, created_by_user:)
+    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:
-    return if tag.tag_versions.exists?
+    if tag.nico?
+      return if tag.nico_tag_versions.exists?
 
-    TagVersionRecorder.record!(tag:, event_type: :create, created_by_user:)
+      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:)
+    end
   end
 
   def self.record_tag_snapshot! tag, created_by_user:
-    event_type = tag.tag_versions.exists? ? :update : :create
+    event_type =
+        if tag.nico?
+          tag.nico_tag_versions.exists? ? :update : :create
+        else
+          tag.tag_versions.exists? ? :update : :create
+        end
+
     record!(tag, event_type:, created_by_user:)
   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/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

@@ -0,0 +1,20 @@
+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

@@ -0,0 +1,20 @@
+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
+    end
+
+    execute <<~SQL
+      INSERT INTO
+        scripts(code, name, created_at)
+      VALUES
+        ('Jpan', '漢字および仮名文字', #{ connection.quote Time.current })
+    SQL
+  end
+
+  def down
+    drop_table :scripts
+  end
+end

backend/db/migrate/20260922020000_create_locales.rb

@@ -0,0 +1,25 @@
+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.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
+    end
+
+    execute <<~SQL
+      INSERT INTO
+        locales(code, language_code, script_code, name, created_at)
+      VALUES
+        ('ja', 'ja', 'Jpan', '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

@@ -0,0 +1,59 @@
+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_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
+  end
+
+  def down
+    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, :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/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_09_21_230000) do
+ActiveRecord::Schema[8.0].define(version: 2026_09_21_030000) 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_09_21_230000) 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
@@ -289,13 +281,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_21_230000) 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
@@ -367,7 +352,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_21_230000) 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|
@@ -715,11 +700,9 @@ ActiveRecord::Schema[8.0].define(version: 2026_09_21_230000) do
   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", "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"

backend/lib/tasks/sync_nico.rake

@@ -30,28 +30,9 @@ 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).find_each do |pt|
-    end
+        pt.destroy!
-
-    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
-          .where(post_id: post.id, external_tag_id: to_remove.to_a)
-          .find_each(&:destroy!)
     end
 
     mysql_user = ENV['MYSQL_USER']
@@ -130,63 +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.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|
-        tag = ExternalTag.find_or_create_by!(platform: :nico, name: raw)
+        name = TagNameSanitisationRule.sanitise("nico:#{ raw }")
+        tag = Tag.find_or_create_by_tag_name!(Locale.nipponese, 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/tasks/nico_sync_spec.rb

@@ -378,119 +378,4 @@ RSpec.describe 'nico:sync' do
     expect(versions.second.title).to eq('changed title')
     expect(versions.second.tags).to eq(snapshot_tags(post.reload))
   end
-
-  def create_external_tag!(name)
-    ExternalTag.create!(platform: :nico, name:)
-  end
-
-  def create_nico_sync_post!
-    post = Post.create!(
-      title: 't',
-      url: 'https://www.nicovideo.jp/watch/sm9',
-      uploaded_user: nil
-    )
-
-    PostTag.create!(post:, tag: Tag.no_deerjikist)
-
-    post
-  end
-
-  def run_nico_sync_with_tags! tags
-    stub_python([{
-      'code' => 'sm9',
-      'title' => 't',
-      'tags' => tags,
-      'user' => nil
-    }])
-
-    allow(URI).to receive(:open).and_return(StringIO.new('<html></html>'))
-
-    run_rake_task('nico:sync')
-  end
-
-  it '外部タグが新規記載されたとき，その時点の連携タグを記載する' do
-    post = create_nico_sync_post!
-
-    external_tag = create_external_tag!('AAA')
-    linked_tag = create_tag!('spec_linked', category: :general)
-    link_nico_to_tag!(external_tag, linked_tag)
-
-    run_nico_sync_with_tags!(['AAA'])
-
-    expect(post.reload.external_tags).to include(external_tag)
-    expect(post.tags).to include(linked_tag)
-  end
-
-  it '外部タグに差分がない場合，内外マッピングが変はっても連携タグを再評価しない' do
-    post = create_nico_sync_post!
-
-    external_tag = create_external_tag!('AAA')
-    old_linked_tag = create_tag!('spec_old_linked', category: :general)
-    new_linked_tag = create_tag!('spec_new_linked', category: :general)
-
-    relation = link_nico_to_tag!(external_tag, old_linked_tag)
-
-    run_nico_sync_with_tags!(['AAA'])
-
-    expect(post.reload.tags).to include(old_linked_tag)
-
-    # 人手で連携タグを消除する．
-    PostTag.find_by!(post:, tag: old_linked_tag).destroy!
-
-    # 内外マッピングを変更する．
-    relation.destroy!
-    link_nico_to_tag!(external_tag, new_linked_tag)
-
-    # 外部タグ自体には差分が無い．
-    run_nico_sync_with_tags!(['AAA'])
-
-    post.reload
-
-    expect(post.external_tags).to include(external_tag)
-    expect(post.tags).not_to include(old_linked_tag)
-    expect(post.tags).not_to include(new_linked_tag)
-  end
-
-  it '外部タグの消除では連携タグを消除せず，再記載時にその時点の内外マッピングを適用する' do
-    post = create_nico_sync_post!
-
-    external_tag = create_external_tag!('AAA')
-    old_linked_tag = create_tag!('spec_old_linked', category: :general)
-    new_linked_tag = create_tag!('spec_new_linked', category: :general)
-
-    relation = link_nico_to_tag!(external_tag, old_linked_tag)
-
-    # 外部タグを新規記載する．
-    run_nico_sync_with_tags!(['AAA'])
-
-    post.reload
-    expect(post.external_tags).to include(external_tag)
-    expect(post.tags).to include(old_linked_tag)
-
-    # 外部タグを消除する．
-    run_nico_sync_with_tags!([])
-
-    post.reload
-    expect(post.external_tags).not_to include(external_tag)
-
-    # 外部タグの消除によって連携タグまでは消除されない．
-    expect(post.tags).to include(old_linked_tag)
-
-    # 外部タグが記載されてゐない間に内外マッピングを変更する．
-    relation.destroy!
-    link_nico_to_tag!(external_tag, new_linked_tag)
-
-    # 同じ外部タグを再記載する．
-    run_nico_sync_with_tags!(['AAA'])
-
-    post.reload
-
-    expect(post.external_tags).to include(external_tag)
-
-    # 旧連携タグは自動的には消除されない．
-    expect(post.tags).to include(old_linked_tag)
-
-    # 再記載時点の内外マッピングが新たに適用される．
-    expect(post.tags).to include(new_linked_tag)
-  end
 end