#106 誤字

backend/.rspec

@@ -1 +0,0 @@
---require spec_helper

backend/Gemfile

@@ -46,10 +46,10 @@ group :development, :test do
 
   # Omakase Ruby styling [https://github.com/rails/rubocop-rails-omakase/]
   gem "rubocop-rails-omakase", require: false
-
-  gem 'factory_bot_rails'
 end
 
+
+
 gem "mysql2", "~> 0.5.6"
 
 gem "image_processing", "~> 1.14"
@@ -65,7 +65,3 @@ gem 'dotenv-rails'
 gem 'whenever', require: false
 
 gem 'discard'
-
-gem "rspec-rails", "~> 8.0", :groups => [:development, :test]
-
-gem 'aws-sdk-s3', require: false

backend/Gemfile.lock

@@ -73,25 +73,6 @@ GEM
       tzinfo (~> 2.0, >= 2.0.5)
       uri (>= 0.13.1)
     ast (2.4.3)
-    aws-eventstream (1.4.0)
-    aws-partitions (1.1231.0)
-    aws-sdk-core (3.244.0)
-      aws-eventstream (~> 1, >= 1.3.0)
-      aws-partitions (~> 1, >= 1.992.0)
-      aws-sigv4 (~> 1.9)
-      base64
-      bigdecimal
-      jmespath (~> 1, >= 1.6.1)
-      logger
-    aws-sdk-kms (1.123.0)
-      aws-sdk-core (~> 3, >= 3.244.0)
-      aws-sigv4 (~> 1.5)
-    aws-sdk-s3 (1.217.0)
-      aws-sdk-core (~> 3, >= 3.244.0)
-      aws-sdk-kms (~> 1)
-      aws-sigv4 (~> 1.5)
-    aws-sigv4 (1.12.1)
-      aws-eventstream (~> 1, >= 1.0.2)
     base64 (0.2.0)
     bcrypt_pbkdf (1.1.1)
     bcrypt_pbkdf (1.1.1-arm64-darwin)
@@ -118,11 +99,6 @@ GEM
     drb (2.2.1)
     ed25519 (1.4.0)
     erubi (1.13.1)
-    factory_bot (6.5.6)
-      activesupport (>= 6.1.0)
-    factory_bot_rails (6.5.1)
-      factory_bot (~> 6.5)
-      railties (>= 6.1.0)
     ffi (1.17.2-aarch64-linux-gnu)
     ffi (1.17.2-aarch64-linux-musl)
     ffi (1.17.2-arm-linux-gnu)
@@ -176,7 +152,6 @@ GEM
       pp (>= 0.6.0)
       rdoc (>= 4.0.0)
       reline (>= 0.4.2)
-    jmespath (1.6.2)
     json (2.12.0)
     jwt (2.10.1)
       base64
@@ -323,23 +298,6 @@ GEM
       io-console (~> 0.5)
     rexml (3.4.1)
     rouge (3.30.0)
-    rspec-core (3.13.6)
-      rspec-support (~> 3.13.0)
-    rspec-expectations (3.13.5)
-      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.13.0)
-    rspec-mocks (3.13.7)
-      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.13.0)
-    rspec-rails (8.0.2)
-      actionpack (>= 7.2)
-      activesupport (>= 7.2)
-      railties (>= 7.2)
-      rspec-core (~> 3.13)
-      rspec-expectations (~> 3.13)
-      rspec-mocks (~> 3.13)
-      rspec-support (~> 3.13)
-    rspec-support (3.13.6)
     rss (0.3.1)
       rexml
     rubocop (1.75.6)
@@ -461,13 +419,11 @@ PLATFORMS
   x86_64-linux-musl
 
 DEPENDENCIES
-  aws-sdk-s3
   bootsnap
   brakeman
   diff-lcs
   discard
   dotenv-rails
-  factory_bot_rails
   gollum
   image_processing (~> 1.14)
   jwt
@@ -477,7 +433,6 @@ DEPENDENCIES
   puma (>= 5.0)
   rack-cors
   rails (~> 8.0.2)
-  rspec-rails (~> 8.0)
   rubocop-rails-omakase
   sprockets-rails
   sqlite3 (>= 2.1)

backend/app/controllers/application_controller.rb

@@ -11,15 +11,4 @@ class ApplicationController < ActionController::API
     code = request.headers['X-Transfer-Code'] || request.headers['HTTP_X_TRANSFER_CODE']
     @current_user = User.find_by(inheritance_code: code)
   end
-
-  def bool? key, default: false
-    return default if params[key].nil?
-
-    s = params[key].to_s.strip.downcase
-    if default
-      !(s.in?(['0', 'false', 'off', 'no']))
-    else
-      s.in?(['', '1', 'true', 'on', 'yes'])
-    end
-  end
 end

backend/app/controllers/deerjikists_controller.rb

@@ -1,47 +0,0 @@
-class DeerjikistsController < ApplicationController
-  def show
-    platform = params[:platform].to_s.strip
-    code = params[:code].to_s.strip
-    return head :bad_request if platform.blank? || code.blank?
-
-    deerjikist = Deerjikist
-                 .joins(:tag)
-                 .includes(tag: :tag_name)
-                 .find_by(platform:, code:)
-    if deerjikist
-      render json: DeerjikistRepr.base(deerjikist)
-    else
-      head :not_found
-    end
-  end
-
-  def update
-    return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
-
-    platform = params[:platform].to_s.strip
-    code = params[:code].to_s.strip
-    tag_id = params[:tag_id].to_i
-    return head :bad_request if platform.blank? || code.blank? || tag_id <= 0
-
-    deerjikist = Deerjikist.find_or_initialize_by(platform:, code:).tap do |d|
-      d.tag_id = tag_id
-      d.save!
-    end
-
-    render json: DeerjikistRepr.base(deerjikist)
-  end
-
-  def destroy
-    return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
-
-    platform = params[:platform].to_s.strip
-    code = params[:code].to_s.strip
-    return head :bad_request if platform.blank? || code.blank?
-
-    Deerjikist.find([platform, code]).destroy!
-
-    head :no_content
-  end
-end

backend/app/controllers/ip_addresses_controller.rb

@@ -0,0 +1,20 @@
+class IpAddressesController < ApplicationController
+  def index
+    @ip_addresses = IpAddress.all
+
+    render json: @ip_addresses
+  end
+
+  def show
+    render json: @ip_address
+  end
+
+  def create
+  end
+
+  def update
+  end
+
+  def destroy
+  end
+end

backend/app/controllers/materials_controller.rb

@@ -1,101 +0,0 @@
-class MaterialsController < ApplicationController
-  def index
-    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
-
-    tag_id = params[:tag_id].presence
-    parent_id = params[:parent_id].presence
-
-    q = Material.includes(:tag, :created_by_user).with_attached_file
-    q = q.where(tag_id:) if tag_id
-    q = q.where(parent_id:) if parent_id
-
-    count = q.count
-    materials = q.order(created_at: :desc, id: :desc).limit(limit).offset(offset)
-
-    render json: { materials: MaterialRepr.many(materials, host: request.base_url), count: count }
-  end
-
-  def show
-    material =
-        Material
-        .includes(:tag)
-        .with_attached_file
-        .find_by(id: params[:id])
-    return head :not_found unless material
-
-    wiki_page_body = material.tag.tag_name.wiki_page&.current_revision&.body
-
-    render json: MaterialRepr.base(material, host: request.base_url).merge(wiki_page_body:)
-  end
-
-  def create
-    return head :unauthorized unless current_user
-
-    tag_name_raw = params[:tag].to_s.strip
-    file = params[:file]
-    url = params[:url].to_s.strip.presence
-    return head :bad_request if tag_name_raw.blank? || (file.blank? && url.blank?)
-
-    tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
-    tag = tag_name.tag
-    tag = Tag.create!(tag_name:, category: :material) unless tag
-
-    material = Material.new(tag:, url:,
-                            created_by_user: current_user,
-                            updated_by_user: current_user)
-    material.file.attach(file)
-
-    if material.save
-      render json: MaterialRepr.base(material, host: request.base_url), status: :created
-    else
-      render json: { errors: material.errors.full_messages }, status: :unprocessable_entity
-    end
-  end
-
-  def update
-    return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
-
-    material = Material.with_attached_file.find_by(id: params[:id])
-    return head :not_found unless material
-
-    tag_name_raw = params[:tag].to_s.strip
-    file = params[:file]
-    url = params[:url].to_s.strip.presence
-    return head :bad_request if tag_name_raw.blank? || (file.blank? && url.blank?)
-
-    tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
-    tag = tag_name.tag
-    tag = Tag.create!(tag_name:, category: :material) unless tag
-
-    material.update!(tag:, url:, updated_by_user: current_user)
-    if file
-      material.file.attach(file)
-    else
-      material.file.purge
-    end
-
-    if material.save
-      render json: MaterialRepr.base(material, host: request.base_url)
-    else
-      render json: { errors: material.errors.full_messages }, status: :unprocessable_entity
-    end
-  end
-
-  def destroy
-    return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
-
-    material = Material.find_by(id: params[:id])
-    return head :not_found unless material
-
-    material.discard
-    head :no_content
-  end
-end

backend/app/controllers/nico_tag_relation_controller.rb

@@ -0,0 +1,16 @@
+class NicoTagRelationController < ApplicationController
+  def index
+  end
+
+  def show
+  end
+
+  def create
+  end
+
+  def update
+  end
+
+  def destroy
+  end
+end

backend/app/controllers/nico_tags_controller.rb

@@ -3,12 +3,10 @@ class NicoTagsController < ApplicationController
     limit = (params[:limit] || 20).to_i
     cursor = params[:cursor].presence
 
-    q = Tag.nico_tags
-           .includes(:tag_name, tag_name: :wiki_page, linked_tags: { tag_name: :wiki_page })
-           .order(updated_at: :desc)
+    q = Tag.nico_tags.includes(:linked_tags).order(updated_at: :desc)
     q = q.where('tags.updated_at < ?', Time.iso8601(cursor)) if cursor
 
-    tags = q.limit(limit + 1).to_a
+    tags = q.limit(limit + 1)
 
     next_cursor = nil
     if tags.size > limit
@@ -17,15 +15,13 @@ class NicoTagsController < ApplicationController
     end
 
     render json: { tags: tags.map { |tag|
-      TagRepr.base(tag).merge(linked_tags: tag.linked_tags.map { |lt|
-        TagRepr.base(lt)
-      })
+      tag.as_json(include: :linked_tags)
     }, next_cursor: }
   end
 
   def update
     return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
+    return head :forbidden unless current_user.member?
 
     id = params[:id].to_i
 
@@ -34,11 +30,12 @@ class NicoTagsController < ApplicationController
 
     linked_tag_names = params[:tags].to_s.split(' ')
     linked_tags = Tag.normalise_tags(linked_tag_names, with_tagme: false)
-    return head :bad_request if linked_tags.any? { |t| t.category == 'nico' }
+    return head :bad_request if linked_tags.filter { |t| t.category == 'nico' }.present?
 
     tag.linked_tags = linked_tags
+    tag.updated_at = Time.now
     tag.save!
 
-    render json: tag.linked_tags.map { |t| TagRepr.base(t) }, status: :ok
+    render json: tag.linked_tags, status: :ok
   end
 end

backend/app/controllers/post_tags_controller.rb

@@ -0,0 +1,16 @@
+class PostTagsController < ApplicationController
+  def index
+  end
+
+  def show
+  end
+
+  def create
+  end
+
+  def update
+  end
+
+  def destroy
+  end
+end

backend/app/controllers/posts_controller.rb

@@ -1,89 +1,42 @@
 class PostsController < ApplicationController
   Event = Struct.new(:post, :tag, :user, :change_type, :timestamp, keyword_init: true)
 
+  # GET /posts
   def index
-    url = params[:url].presence
-    title = params[:title].presence
-    original_created_from = params[:original_created_from].presence
-    original_created_to = params[:original_created_to].presence
-    created_between = params[:created_from].presence, params[:created_to].presence
-    updated_between = params[:updated_from].presence, params[:updated_to].presence
-
-    order = params[:order].to_s.split(':', 2).map(&:strip)
-    unless order[0].in?(['title', 'url', 'original_created_at', 'created_at', 'updated_at'])
-      order[0] = 'original_created_at'
-    end
-    unless order[1].in?(['asc', 'desc'])
-      order[1] =
-          if order[0].in?(['title', 'url'])
-            'asc'
-          else
-            'desc'
-          end
-    end
-
     page = (params[:page].presence || 1).to_i
     limit = (params[:limit].presence || 20).to_i
+    cursor = params[:cursor].presence
 
     page = 1 if page < 1
     limit = 1 if limit < 1
 
     offset = (page - 1) * limit
 
-    pt_max_sql =
-        PostTag
-        .select('post_id, MAX(updated_at) AS max_updated_at')
-        .group('post_id')
-        .to_sql
-
-    updated_at_all_sql =
-        'GREATEST(posts.updated_at,' +
-        'COALESCE(pt_max.max_updated_at, posts.updated_at))'
-
-    q =
-        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(tags: { tag_name: :wiki_page })
-        .with_attached_thumbnail
-
-    q = q.where('posts.url LIKE ?', "%#{ url }%") if url
-    q = q.where('posts.title LIKE ?', "%#{ title }%") if title
-    if original_created_from
-      q = q.where('posts.original_created_before > ?', original_created_from)
-    end
-    if original_created_to
-      q = q.where('posts.original_created_from <= ?', original_created_to)
-    end
-    q = q.where('posts.created_at >= ?', created_between[0]) if created_between[0]
-    q = q.where('posts.created_at <= ?', created_between[1]) if created_between[1]
-    if updated_between[0]
-      q = q.where("#{ updated_at_all_sql } >= ?", updated_between[0])
-    end
-    if updated_between[1]
-      q = q.where("#{ updated_at_all_sql } <= ?", updated_between[1])
-    end
-
     sort_sql =
-        case order[0]
-        when 'original_created_at'
-          'COALESCE(posts.original_created_before - INTERVAL 1 MINUTE,' +
+        'COALESCE(posts.original_created_before - INTERVAL 1 SECOND,' +
         'posts.original_created_from,' +
         'posts.created_at)'
-        when 'updated_at'
-          updated_at_all_sql
+    q =
+        filtered_posts
+        .preload(:tags)
+        .with_attached_thumbnail
+        .select("posts.*, #{ sort_sql } AS sort_ts")
+        .order(Arel.sql("#{ sort_sql } DESC"))
+    posts = (
+        if cursor
+          q.where("#{ sort_sql } < ?", Time.iso8601(cursor)).limit(limit + 1)
         else
-          "posts.#{ order[0] }"
-        end
-    posts = q.order(Arel.sql("#{ sort_sql } #{ order[1] }, posts.id #{ order[1] }"))
-             .limit(limit)
-             .offset(offset)
-             .to_a
+          q.limit(limit).offset(offset)
+        end).to_a
 
-    q = q.except(:select, :order)
+    next_cursor = nil
+    if cursor && posts.length > limit
+      next_cursor = posts.last.read_attribute('sort_ts').iso8601(6)
+      posts = posts.first(limit)
+    end
 
     render json: { posts: posts.map { |post|
-      PostRepr.base(post).merge(updated_at: post.updated_at_all).tap do |json|
+      post.as_json(include: { tags: { only: [:id, :name, :category, :post_count] } }).tap do |json|
         json['thumbnail'] =
             if post.thumbnail.attached?
               rails_storage_proxy_url(post.thumbnail, only_path: false)
@@ -91,58 +44,63 @@ class PostsController < ApplicationController
               nil
             end
       end
-    }, count: q.group_values.present? ? q.count.size : q.count }
+    }, count: filtered_posts.count(:id), next_cursor: }
   end
 
   def random
-    post = filtered_posts.preload(tags: { tag_name: :wiki_page })
-                         .order('RAND()')
-                         .first
+    post = filtered_posts.order('RAND()').first
     return head :not_found unless post
 
-    render json: PostRepr.base(post, current_user)
+    viewed = current_user&.viewed?(post) || false
+
+    render json: (post
+                  .as_json(include: { tags: { only: [:id, :name, :category, :post_count] } })
+                  .merge(viewed:))
   end
 
+  # GET /posts/1
   def show
-    post = Post.includes(tags: { tag_name: :wiki_page }).find_by(id: params[:id])
+    post = Post.includes(:tags).find(params[:id])
     return head :not_found unless post
 
-    render json: PostRepr.base(post, current_user)
-                         .merge(tags: build_tag_tree_for(post.tags),
-                                related: post.related(limit: 20))
+    viewed = current_user&.viewed?(post) || false
+
+    json = post.as_json
+    json['tags'] = build_tag_tree_for(post.tags)
+    json['related'] = post.related(limit: 20)
+    json['viewed'] = viewed
+
+    render json:
   end
 
+  # POST /posts
   def create
     return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
+    return head :forbidden unless current_user.member?
 
+    # TODO: URL が正規のものがチェック，不正ならエラー
+    # TODO: URL は必須にする（タイトルは省略可）．
     # TODO: サイトに応じて thumbnail_base 設定
-    title = params[:title].presence
+    title = params[:title]
     url = params[:url]
     thumbnail = params[:thumbnail]
-    tag_names = params[:tags].to_s.split
+    tag_names = params[:tags].to_s.split(' ')
     original_created_from = params[:original_created_from]
     original_created_before = params[:original_created_before]
 
-    post = Post.new(title:, url:, thumbnail_base: nil, uploaded_user: current_user,
+    post = Post.new(title:, url:, thumbnail_base: '', uploaded_user: current_user,
                     original_created_from:, original_created_before:)
     post.thumbnail.attach(thumbnail)
-
-    ActiveRecord::Base.transaction do
-      post.save!
+    if post.save
+      post.resized_thumbnail!
       tags = Tag.normalise_tags(tag_names)
       tags = Tag.expand_parent_tags(tags)
       sync_post_tags!(post, tags)
-      post.resized_thumbnail!
-      PostVersionRecorder.record!(post:, event_type: :create, created_by_user: current_user)
-    end
-
-    post.reload
-    render json: PostRepr.base(post), status: :created
-  rescue ActiveRecord::RecordInvalid
+      render json: post.as_json(include: { tags: { only: [:id, :name, :category, :post_count] } }),
+             status: :created
+    else
       render json: { errors: post.errors.full_messages }, status: :unprocessable_entity
-  rescue Tag::NicoTagNormalisationError
-    head :bad_request
+    end
   end
 
   def viewed
@@ -159,39 +117,36 @@ class PostsController < ApplicationController
     head :no_content
   end
 
+  # PATCH/PUT /posts/1
   def update
     return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
+    return head :forbidden unless current_user.member?
 
-    title = params[:title].presence
-    tag_names = params[:tags].to_s.split
+    title = params[:title]
+    tag_names = params[:tags].to_s.split(' ')
     original_created_from = params[:original_created_from]
     original_created_before = params[:original_created_before]
 
     post = Post.find(params[:id].to_i)
-
-    ActiveRecord::Base.transaction do
-      post.update!(title:, original_created_from:, original_created_before:)
+    if post.update(title:, original_created_from:, original_created_before:)
       tags = post.tags.where(category: 'nico').to_a +
              Tag.normalise_tags(tag_names, with_tagme: false)
       tags = Tag.expand_parent_tags(tags)
       sync_post_tags!(post, tags)
-      PostVersionRecorder.record!(post:, event_type: :update, created_by_user: current_user)
-    end
-
-    post.reload
       json = post.as_json
       json['tags'] = build_tag_tree_for(post.tags)
       render json:, status: :ok
-  rescue ActiveRecord::RecordInvalid
+    else
       render json: post.errors, status: :unprocessable_entity
-  rescue Tag::NicoTagNormalisationError
-    head :bad_request
+    end
+  end
+
+  # DELETE /posts/1
+  def destroy
   end
 
   def changes
-    id = params[:id].presence
-    tag_id = params[:tag].presence
+    id = params[:id]
     page = (params[:page].presence || 1).to_i
     limit = (params[:limit].presence || 20).to_i
 
@@ -202,26 +157,21 @@ class PostsController < ApplicationController
 
     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: { tag_name: :wiki_page })
+    pts = pts.includes(:post, :tag, :created_user, :deleted_user)
 
     events = []
     pts.each do |pt|
-      tag = TagRepr.base(pt.tag)
-      post = pt.post
-
       events << Event.new(
-          post:,
-          tag:,
+          post:         pt.post,
+          tag:          pt.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:,
+            post:         pt.post,
+            tag:          pt.tag,
             user:         pt.deleted_user && { id: pt.deleted_user.id, name: pt.deleted_user.name },
             change_type:  'remove',
             timestamp:    pt.discarded_at)
@@ -230,13 +180,13 @@ class PostsController < ApplicationController
     events.sort_by!(&:timestamp)
     events.reverse!
 
-    render json: { changes: (events.slice(offset, limit) || []).as_json, count: events.size }
+    render json: { changes: events.slice(offset, limit).as_json, count: events.size }
   end
 
   private
 
   def filtered_posts
-    tag_names = params[:tags].to_s.split
+    tag_names = params[:tags]&.split(' ')
     match_type = params[:match]
     if tag_names.present?
       filter_posts_by_tags(tag_names, match_type)
@@ -246,40 +196,16 @@ class PostsController < ApplicationController
   end
 
   def filter_posts_by_tags tag_names, match_type
-    literals = tag_names.map do |raw_name|
-      { name: TagName.canonicalise(raw_name.sub(/\Anot:/i, '')).first,
-        negative: raw_name.downcase.start_with?('not:') }
-    end
-
-    return Post.all if literals.empty?
-
+    posts = Post.joins(:tags)
     if match_type == 'any'
-      literals.reduce(Post.none) do |posts, literal|
-        posts.or(tag_literal_relation(literal[:name], negative: literal[:negative]))
-      end
+      posts = posts.where(tags: { name: tag_names }).distinct
     else
-      literals.reduce(Post.all) do |posts, literal|
-        ids = tagged_post_ids_for(literal[:name])
-        if literal[:negative]
-          posts.where.not(id: ids)
-        else
-          posts.where(id: ids)
+      tag_names.each do |tag|
+        posts = posts.where(id: Post.joins(:tags).where(tags: { name: tag }))
       end
     end
+    posts.distinct
   end
-  end
-
-  def tag_literal_relation name, negative:
-    ids = tagged_post_ids_for(name)
-    if negative
-      Post.where.not(id: ids)
-    else
-      Post.where(id: ids)
-    end
-  end
-
-  def tagged_post_ids_for(name) =
-      Post.joins(tags: :tag_name).where(tag_names: { name: }).select(:id)
 
   def sync_post_tags! post, desired_tags
     desired_tags.each do |t|
@@ -329,7 +255,7 @@ class PostsController < ApplicationController
       return nil unless tag
 
       if path.include?(tag_id)
-        return TagRepr.base(tag).merge(children: [])
+        return tag.as_json(only: [:id, :name, :category, :post_count]).merge(children: [])
       end
 
       if memo.key?(tag_id)
@@ -341,7 +267,7 @@ class PostsController < ApplicationController
 
       children = child_ids.filter_map { |cid| build_node.(cid, new_path) }
 
-      memo[tag_id] = TagRepr.base(tag).merge(children:)
+      memo[tag_id] = tag.as_json(only: [:id, :name, :category, :post_count]).merge(children:)
     end
 
     root_ids.filter_map { |id| build_node.call(id, []) }

backend/app/controllers/settings_controller.rb

@@ -0,0 +1,16 @@
+class SettingsController < ApplicationController
+  def index
+  end
+
+  def show
+  end
+
+  def create
+  end
+
+  def update
+  end
+
+  def destroy
+  end
+end

backend/app/controllers/tag_aliases_controller.rb

@@ -0,0 +1,16 @@
+class TagAliasesController < ApplicationController
+  def index
+  end
+
+  def show
+  end
+
+  def create
+  end
+
+  def update
+  end
+
+  def destroy
+  end
+end

backend/app/controllers/tag_children_controller.rb

@@ -1,27 +0,0 @@
-class TagChildrenController < ApplicationController
-  def create
-    return head :unauthorized unless current_user
-    return head :forbidden unless current_user.admin?
-
-    parent_id = params[:parent_id]
-    child_id = params[:child_id]
-    return head :bad_request if parent_id.blank? || child_id.blank?
-
-    Tag.find(parent_id).children << Tag.find(child_id) rescue nil
-
-    head :no_content
-  end
-
-  def destroy
-    return head :unauthorized unless current_user
-    return head :forbidden unless current_user.admin?
-
-    parent_id = params[:parent_id]
-    child_id = params[:child_id]
-    return head :bad_request if parent_id.blank? || child_id.blank?
-
-    Tag.find(parent_id).children.delete(Tag.find(child_id)) rescue nil
-
-    head :no_content
-  end
-end

backend/app/controllers/tags_controller.rb

@@ -1,247 +1,46 @@
 class TagsController < ApplicationController
   def index
     post_id = params[:post]
-
-    name = params[:name].presence
-    category = params[:category].presence
-    post_count_between = (params[:post_count_gte].presence || -1).to_i,
-                         (params[:post_count_lte].presence || -1).to_i
-    post_count_between[0] = nil if post_count_between[0] < 0
-    post_count_between[1] = nil if post_count_between[1] < 0
-    created_between = params[:created_from].presence, params[:created_to].presence
-    updated_between = params[:updated_from].presence, params[:updated_to].presence
-
-    order = params[:order].to_s.split(':', 2).map(&:strip)
-    unless order[0].in?(['name', 'category', 'post_count', 'created_at', 'updated_at'])
-      order[0] = 'post_count'
-    end
-    unless order[1].in?(['asc', 'desc'])
-      order[1] = order[0].in?(['name', 'category']) ? 'asc' : 'desc'
-    end
-
-    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
-
-    q =
-        if post_id.present?
-          Tag.joins(:posts, :tag_name)
+    tags = if post_id.present?
+             Tag.joins(:posts).where(posts: { id: post_id })
            else
-          Tag.joins(:tag_name)
+             Tag.all
            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]
-
-    sort_sql =
-        case order[0]
-        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 END"
-        else
-          "tags.#{ order[0] }"
-        end
-    tags = q.order(Arel.sql("#{ sort_sql } #{ order[1] }, tags.id #{ order[1] }"))
-            .limit(limit)
-            .offset(offset)
-            .to_a
-
-    render json: { tags: TagRepr.base(tags), count: q.size }
-  end
-
-  def with_depth
-    parent_tag_id = params[:parent].to_i
-    parent_tag_id = nil if parent_tag_id <= 0
-
-    tag_ids =
-        if parent_tag_id
-          TagImplication.where(parent_tag_id:).select(:tag_id)
-        else
-          Tag.where.not(id: TagImplication.select(:tag_id)).select(:id)
-        end
-
-    tags =
-        Tag
-        .joins(:tag_name)
-        .includes(:tag_name, :materials, tag_name: :wiki_page)
-        .where(category: [:meme, :character, :material])
-        .where(id: tag_ids)
-        .order('tag_names.name')
-        .distinct
-        .to_a
-
-    has_children_tag_ids =
-        if tags.empty?
-          []
-        else
-          TagImplication
-              .joins(:tag)
-              .where(parent_tag_id: tags.map(&:id),
-                     tags: { category: [:meme, :character, :material] })
-              .distinct
-              .pluck(:parent_tag_id)
-        end
-
-    render json: tags.map { |tag|
-      TagRepr.base(tag).merge(has_children: has_children_tag_ids.include?(tag.id), children: [])
-    }
+    render json: tags
   end
 
   def autocomplete
-    q = params[:q].to_s.strip.sub(/\Anot:/i, '')
+    q = params[:q].to_s.strip
+    return render json: [] if q.blank?
 
-    with_nico = bool?(:nico, default: true)
-    present_only = bool?(:present, default: true)
-
-    alias_rows =
-        TagName
-        .where('name LIKE ?', "#{ q }%")
-        .where.not(canonical_id: nil)
-        .pluck(:canonical_id, :name)
-
-    matched_alias_by_tag_name_id = { }
-    canonical_ids = []
-
-    alias_rows.each do |canonical_id, alias_name|
-      canonical_ids << canonical_id
-      matched_alias_by_tag_name_id[canonical_id] ||= alias_name
-    end
-
-    base = Tag.joins(:tag_name)
-              .includes(:tag_name, :materials, tag_name: :wiki_page)
-    base = base.where('tags.post_count > 0') if present_only
-
-    canonical_hit =
-        base
-        .where(((with_nico ? '(tags.category = ? AND tag_names.name LIKE ?) OR ' : '') +
-                'tag_names.name LIKE ?'),
-               *(with_nico ? ['nico', "nico:#{ q }%"] : []), "#{ q }%")
-
-    tags =
-        if canonical_ids.present?
-          canonical_hit.or(base.where(tag_name_id: canonical_ids.uniq))
-        else
-          canonical_hit
-        end
-
-    tags = tags.order(Arel.sql('post_count DESC, tag_names.name')).limit(20).to_a
-
-    render json: tags.map { |tag|
-      TagRepr.base(tag).merge(matched_alias: matched_alias_by_tag_name_id[tag.tag_name_id])
-    }
+    tags = (Tag
+            .where('(category = ? AND name LIKE ?) OR name LIKE ?',
+                   'nico', "nico:#{ q }%", "#{ q }%")
+            .order('post_count DESC, name ASC')
+            .limit(20))
+    render json: tags
   end
 
   def show
-    tag = Tag.joins(:tag_name)
-             .includes(:tag_name, :materials, tag_name: :wiki_page)
-             .find_by(id: params[:id])
-    if tag
-      render json: TagRepr.base(tag)
-    else
-      head :not_found
-    end
+    tag = Tag.find(params[:id])
+    render json: tag
   end
 
   def show_by_name
-    name = params[:name].to_s.strip
-    return head :bad_request if name.blank?
-
-    tag = Tag.joins(:tag_name)
-             .includes(:tag_name, :materials, tag_name: :wiki_page)
-             .find_by(tag_names: { name: })
+    tag = Tag.find_by(name: params[:name])
     if tag
-      render json: TagRepr.base(tag)
+      render json: tag
     else
       head :not_found
     end
   end
 
-  def deerjikists
-    tag = Tag.joins(:tag_name)
-             .includes(:tag_name, tag_name: :wiki_page)
-             .find_by(id: params[:id])
-    return head :not_found unless tag
-
-    render json: DeerjikistRepr.many(tag.deerjikists)
-  end
-
-  def deerjikists_by_name
-    name = params[:name].to_s.strip
-    return head :bad_request if name.blank?
-
-    tag = Tag.joins(:tag_name)
-             .includes(:tag_name, tag_name: :wiki_page)
-             .find_by(tag_names: { name: })
-    return head :not_found unless tag
-
-    render json: DeerjikistRepr.many(tag.deerjikists)
-  end
-
-  def materials_by_name
-    name = params[:name].to_s.strip
-    return head :bad_request if name.blank?
-
-    tag = Tag.joins(:tag_name)
-             .includes(:tag_name, :materials, tag_name: :wiki_page)
-             .find_by(tag_names: { name: })
-    return head :not_found unless tag
-
-    render json: build_tag_children(tag)
+  def create
   end
 
   def update
-    return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
-
-    name = params[:name].presence
-    category = params[:category].presence
-
-    tag = Tag.find(params[:id])
-
-    if name.present?
-      tag.tag_name.update!(name:)
   end
 
-    if category.present?
-      tag.update!(category:)
-    end
-
-    render json: TagRepr.base(tag)
-  end
-
-  private
-
-  def build_tag_children(tag)
-    material = tag.materials.first
-    file = nil
-    content_type = nil
-    if material&.file&.attached?
-      file = rails_storage_proxy_url(material.file, only_path: false)
-      content_type = material.file.blob.content_type
-    end
-
-    TagRepr.base(tag).merge(
-        children: tag.children.sort_by { _1.name }.map { build_tag_children(_1) },
-        material: material.as_json&.merge(file:, content_type:))
+  def destroy
   end
 end

backend/app/controllers/theatre_comments_controller.rb

@@ -1,32 +0,0 @@
-class TheatreCommentsController < ApplicationController
-  def index
-    no_gt = params[:no_gt].to_i
-    no_gt = 0 if no_gt.negative?
-
-    comments = TheatreComment
-               .where(theatre_id: params[:theatre_id])
-               .where('no > ?', no_gt)
-               .order(no: :desc)
-
-    render json: comments.as_json(include: { user: { only: [:id, :name] } })
-  end
-
-  def create
-    return head :unauthorized unless current_user
-
-    content = params[:content]
-    return head :unprocessable_entity if content.blank?
-
-    theatre = Theatre.find_by(id: params[:theatre_id])
-    return head :not_found unless theatre
-
-    comment = nil
-    theatre.with_lock do
-      no = theatre.next_comment_no
-      comment = TheatreComment.create!(theatre:, no:, user: current_user, content:)
-      theatre.update!(next_comment_no: no + 1)
-    end
-
-    render json: comment, status: :created
-  end
-end

backend/app/controllers/theatres_controller.rb

@@ -1,54 +0,0 @@
-class TheatresController < ApplicationController
-  def show
-    theatre = Theatre.find_by(id: params[:id])
-    return head :not_found unless theatre
-
-    render json: TheatreRepr.base(theatre)
-  end
-
-  def watching
-    return head :unauthorized unless current_user
-
-    theatre = Theatre.find_by(id: params[:id])
-    return head :not_found unless theatre
-
-    host_flg = false
-    post_id = nil
-    post_started_at = nil
-
-    theatre.with_lock do
-      TheatreWatchingUser.find_or_initialize_by(theatre:, user: current_user).tap {
-        _1.expires_at = 30.seconds.from_now
-      }.save!
-
-      if (!(theatre.host_user_id?) ||
-          !(theatre.watching_users.exists?(id: theatre.host_user_id)))
-        theatre.update!(host_user_id: current_user.id)
-      end
-
-      host_flg = theatre.host_user_id == current_user.id
-      post_id = theatre.current_post_id
-      post_started_at = theatre.current_post_started_at
-    end
-
-    render json: {
-        host_flg:, post_id:, post_started_at:,
-        watching_users: theatre.watching_users.as_json(only: [:id, :name]) }
-  end
-
-  def next_post
-    return head :unauthorized unless current_user
-
-    theatre = Theatre.find_by(id: params[:id])
-    return head :not_found unless theatre
-    return head :forbidden if theatre.host_user != current_user
-
-    post = Post.where("url LIKE '%nicovideo.jp%'")
-           .or(Post.where("url LIKE '%youtube.com%'"))
-           .order('RAND()')
-           .first
-    theatre.update!(current_post: post, current_post_started_at: Time.current)
-
-    head :no_content
-  end
-end

backend/app/controllers/user_ips_controller.rb

@@ -0,0 +1,16 @@
+class UserIpsController < ApplicationController
+  def index
+  end
+
+  def show
+  end
+
+  def create
+  end
+
+  def update
+  end
+
+  def destroy
+  end
+end

backend/app/controllers/user_post_views_controller.rb

@@ -0,0 +1,16 @@
+class UserPostViewsController < ApplicationController
+  def index
+  end
+
+  def show
+  end
+
+  def create
+  end
+
+  def update
+  end
+
+  def destroy
+  end
+end

backend/app/controllers/users_controller.rb

@@ -18,8 +18,6 @@ class UsersController < ApplicationController
   end
 
   def renew
-    return head :unauthorized unless current_user
-
     user = current_user
     user.inheritance_code = SecureRandom.uuid
     user.save!

backend/app/controllers/wiki_pages_controller.rb

@@ -1,34 +1,20 @@
 class WikiPagesController < ApplicationController
-  rescue_from Wiki::Commit::Conflict, with: :render_wiki_conflict
-
   def index
-    title = params[:title].to_s.strip
-    if title.blank?
-      return render json: WikiPageRepr.base(WikiPage.joins(:tag_name).includes(:tag_name))
-    end
+    wiki_pages = WikiPage.all
 
-    q = WikiPage.joins(:tag_name).includes(:tag_name)
-        .where('tag_names.name LIKE ?', "%#{ WikiPage.sanitize_sql_like(title) }%")
-    render json: WikiPageRepr.base(q.limit(20))
+    render json: wiki_pages
   end
 
   def show
-    page = WikiPage.joins(:tag_name)
-                   .includes(:tag_name)
-                   .find_by(id: params[:id])
-    render_wiki_page_or_404 page
+    render_wiki_page_or_404 WikiPage.find(params[:id])
   end
 
   def show_by_title
-    title = params[:title].to_s.strip
-    page = WikiPage.joins(:tag_name)
-                   .includes(:tag_name)
-                   .find_by(tag_name: { name: title })
-    render_wiki_page_or_404 page
+    render_wiki_page_or_404 WikiPage.find_by(title: params[:title])
   end
 
   def exists
-    if WikiPage.exists?(id: params[:id])
+    if WikiPage.exists?(params[:id])
       head :no_content
     else
       head :not_found
@@ -36,8 +22,7 @@ class WikiPagesController < ApplicationController
   end
 
   def exists_by_title
-    title = params[:title].to_s.strip
-    if WikiPage.joins(:tag_name).exists?(tag_names: { name: title })
+    if WikiPage.exists?(title: params[:title])
       head :no_content
     else
       head :not_found
@@ -46,25 +31,21 @@ class WikiPagesController < ApplicationController
 
   def diff
     id = params[:id]
-    return head :bad_request if id.blank?
-
-    from = params[:from].presence
+    from = params[:from]
     to = params[:to].presence
+    return head :bad_request if id.blank? || from.blank?
 
-    page = WikiPage.joins(:tag_name).includes(:tag_name).find(id)
+    wiki_page_from = WikiPage.find(id)
+    wiki_page_to = WikiPage.find(id)
+    wiki_page_from.sha = from
+    wiki_page_to.sha = to
 
-    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?))
-      return head :unprocessable_entity
-    end
-
-    diffs = Diff::LCS.sdiff(from_rev&.body&.lines || [], to_rev.body.lines)
+    diffs = Diff::LCS.sdiff(wiki_page_from.body, wiki_page_to.body)
     diff_json = diffs.map { |change|
       case change.action
       when ?=
         { type: 'context', content: change.old_element }
-      when ?!
+      when ?|
         [{ type: 'removed', content: change.old_element },
          { type: 'added', content: change.new_element }]
       when ?+
@@ -74,116 +55,97 @@ class WikiPagesController < ApplicationController
       end
     }.flatten.compact
 
-    render json: { wiki_page_id:      page.id,
-                   title:             page.title,
-                   older_revision_id: from_rev&.id,
-                   newer_revision_id: to_rev.id,
+    render json: { wiki_page_id:  wiki_page_from.id,
+                   title:         wiki_page_from.title,
+                   older_sha:     wiki_page_from.sha,
+                   newer_sha:     wiki_page_to.sha,
                    diff:          diff_json }
   end
 
   def create
     return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
+    return head :forbidden unless ['admin', 'member'].include?(current_user.role)
 
-    name = params[:title]&.strip
-    body = params[:body].to_s
-
-    return head :unprocessable_entity if name.blank? || body.blank?
-
-    tag_name = TagName.find_undiscard_or_create_by!(name:)
-    page = WikiPage.new(tag_name:, created_user: current_user, updated_user: current_user)
-    if page.save
-      message = params[:message].presence
-      Wiki::Commit.content!(page:, body:, created_user: current_user, message:)
-
-      render json: WikiPageRepr.base(page), status: :created
+    wiki_page = WikiPage.new(title: params[:title], created_user: current_user, updated_user: current_user)
+    if wiki_page.save
+      wiki_page.set_body params[:body], user: current_user
+      render json: wiki_page, status: :created
     else
-      render json: { errors: page.errors.full_messages },
-             status: :unprocessable_entity
+      render json: { errors: wiki_page.errors.full_messages }, status: :unprocessable_entity
     end
   end
 
   def update
     return head :unauthorized unless current_user
-    return head :forbidden unless current_user.gte_member?
+    return head :forbidden unless current_user.member?
 
-    title = params[:title]&.strip
-    body = params[:body].to_s
+    title = params[:title]
+    body = params[:body]
 
     return head :unprocessable_entity if title.blank? || body.blank?
 
-    page = WikiPage.find(params[:id])
-    base_revision_id = page.current_revision.id
-
-    if params[:title].present? && params[:title].strip != page.title
-      return head :unprocessable_entity
-    end
-
-    message = params[:message].presence
-    Wiki::Commit.content!(page:,
-                          body:,
-                          created_user: current_user,
-                          message:,
-                          base_revision_id:)
+    wiki_page = WikiPage.find(params[:id])
+    wiki_page.title = title
+    wiki_page.updated_user = current_user
+    wiki_page.set_body(body, user: current_user)
+    wiki_page.save!
 
     head :ok
   end
 
   def search
-    index
+    title = params[:title]&.strip
+
+    q = WikiPage.all
+    q = q.where('title LIKE ?', "%#{ WikiPage.sanitize_sql_like(title) }%") if title.present?
+
+    render json: q.limit(20)
   end
 
   def changes
-    id = params[:id].presence
-    q = WikiRevision.joins(wiki_page: :tag_name)
-                    .includes(:created_user, wiki_page: :tag_name)
-                    .order(id: :desc)
-    q = q.where(wiki_page_id: id) if id
+    id = params[:id]
+    log = if id.present?
+            wiki.page("#{ id }.md")&.versions
+          else
+            wiki.repo.log('main', nil)
+          end
+    return render json: [] unless log
 
-    render json: q.limit(200).map { |rev|
-      { revision_id:  rev.id,
-        pred:         rev.base_revision_id,
-        succ:         nil,
-        wiki_page:    { id: rev.wiki_page_id, title: rev.wiki_page.title },
-        user:         rev.created_user && { id: rev.created_user.id, name: rev.created_user.name },
-        kind:         rev.kind,
-        message:      rev.message,
-        timestamp:    rev.created_at }
+    render json: log.map { |commit|
+      wiki_page = WikiPage.find(commit.message.split(' ')[1].to_i)
+      wiki_page.sha = commit.id
+
+      next nil if wiki_page.sha.blank?
+
+      user = User.find(commit.author.name.to_i)
+
+      { sha:          wiki_page.sha,
+        pred:         wiki_page.pred,
+        succ:         wiki_page.succ,
+        wiki_page:    wiki_page && { id: wiki_page.id, title: wiki_page.title },
+        user:         user && { id: user.id, name: user.name },
+        change_type:  commit.message.split(' ')[0].downcase[0...(-1)],
+        timestamp:    commit.authored_date }
     }.compact
   end
 
   private
 
-  def render_wiki_page_or_404 page
-    return head :not_found unless page
+  WIKI_PATH = Rails.root.join('wiki').to_s
 
-    rev = find_revision(page)
-    return head :not_found unless rev
-
-    if rev.redirect?
-      return (
-          redirect_to wiki_page_by_title_path(title: rev.redirect_page.title),
-                      status: :moved_permanently)
+  def wiki
+    @wiki ||= Gollum::Wiki.new(WIKI_PATH)
   end
 
-    body = rev.body
-    revision_id = rev.id
-    pred = page.pred_revision_id(revision_id)
-    succ = page.succ_revision_id(revision_id)
-    updated_at = rev.created_at
+  def render_wiki_page_or_404 wiki_page
+    return head :not_found unless wiki_page
 
-    render json: WikiPageRepr.base(page).merge(body:, revision_id:, pred:, succ:, updated_at:)
-  end
+    wiki_page.sha = params[:version].presence
 
-  def find_revision page
-    if params[:version].present?
-      page.wiki_revisions.find_by(id: params[:version])
-    else
-      page.current_revision
-    end
-  end
-
-  def render_wiki_conflict err
-    render json: { error: 'conflict', message: err.message }, status: :conflict
+    body = wiki_page.body
+    sha = wiki_page.sha
+    pred = wiki_page.pred
+    succ = wiki_page.succ
+    render json: wiki_page.as_json.merge(body:, sha:, pred:, succ:)
   end
 end

backend/app/models/deerjikist.rb

@@ -1,21 +0,0 @@
-class Deerjikist < ApplicationRecord
-  self.primary_key = :platform, :code
-
-  belongs_to :tag
-
-  validates :platform, presence: true
-  validates :code, presence: true
-  validates :tag_id, presence: true
-
-  validate :tag_must_be_deerjikist
-
-  enum :platform, nico: 'nico', youtube: 'youtube'
-
-  private
-
-  def tag_must_be_deerjikist
-    if tag && !(tag.deerjikist?)
-      errors.add :tag, '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/material.rb

@@ -1,39 +0,0 @@
-class Material < ApplicationRecord
-  include MyDiscard
-
-  default_scope -> { kept }
-
-  belongs_to :parent, class_name: 'Material', optional: true
-  has_many :children, class_name: 'Material', foreign_key: :parent_id, dependent: :nullify
-
-  belongs_to :tag, optional: true
-  belongs_to :created_by_user, class_name: 'User', optional: true
-  belongs_to :updated_by_user, class_name: 'User', optional: true
-
-  has_one_attached :file, dependent: :purge
-
-  validates :tag_id, presence: true, uniqueness: true
-
-  validate :file_must_be_attached
-  validate :tag_must_be_material_category
-
-  def content_type
-    return nil unless file&.attached?
-
-    file.blob.content_type
-  end
-
-  private
-
-  def file_must_be_attached
-    return if url.present? || file.attached?
-
-    errors.add(:url, 'URL かファイルのどちらかは必須です．')
-  end
-
-  def tag_must_be_material_category
-    return if tag.blank? || tag.character? || tag.material?
-
-    errors.add(:tag, '素材カテゴリのタグを指定してください．')
-  end
-end

backend/app/models/my_discard.rb

@@ -1,20 +0,0 @@
-module MyDiscard
-  extend ActiveSupport::Concern
-
-  included { include Discard::Model }
-
-  class_methods do
-    def find_undiscard_or_create_by! attrs, &block
-      record = with_discarded.find_by(attrs)
-
-      if record&.discarded?
-        record.undiscard!
-        record.update_columns(created_at: record.reload.updated_at)
-      end
-
-      record or create!(attrs, &block)
-    rescue ActiveRecord::RecordNotUnique
-      retry
-    end
-  end
-end

backend/app/models/post.rb

@@ -8,19 +8,16 @@ class Post < ApplicationRecord
   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 :user_post_views, dependent: :delete_all
-  has_many :post_similarities, dependent: :delete_all
-  has_many :post_versions
-
+  has_many :user_post_views, dependent: :destroy
+  has_many :post_similarities_as_post,
+           class_name: 'PostSimilarity',
+           foreign_key: :post_id
+  has_many :post_similarities_as_target_post,
+           class_name: 'PostSimilarity',
+           foreign_key: :target_post_id
   has_one_attached :thumbnail
 
-  before_validation :normalise_url
-
-  validates :url, presence: true, uniqueness: true
-
   validate :validate_original_created_range
-  validate :url_must_be_http_url
 
   def as_json options = { }
     super(options).merge({ thumbnail: thumbnail.attached? ?
@@ -31,17 +28,19 @@ class Post < ApplicationRecord
     super(options).merge(thumbnail: nil)
   end
 
-  def snapshot_tag_names = tags.joins(:tag_name).order('tag_names.name').pluck('tag_names.name')
+  def related(limit: nil)
+    ids_with_cos =
+        post_similarities_as_post.select(:target_post_id, :cos)
+                                 .map { |ps| [ps.target_post_id, ps.cos] } +
+        post_similarities_as_target_post.select(:post_id, :cos)
+                                        .map { |ps| [ps.post_id, ps.cos] }
 
-  def related limit: nil
-    ids = post_similarities.order(cos: :desc)
-    ids = ids.limit(limit) if limit
-    ids = ids.pluck(:target_post_id)
-    return Post.none if ids.empty?
+    sorted = ids_with_cos.sort_by { |_, cos| -cos }
 
-    Post.where(id: ids)
-        .with_attached_thumbnail
-        .order(Arel.sql("FIELD(posts.id, #{ ids.join(',') })"))
+    ids = sorted.map(&:first)
+    ids = ids.first(limit) if limit
+
+    Post.where(id: ids).index_by(&:id).values_at(*ids)
   end
 
   def resized_thumbnail!
@@ -70,33 +69,4 @@ class Post < ApplicationRecord
       errors.add :original_created_before, 'オリジナルの作成日時の順番がをかしぃです．'
     end
   end
-
-  def url_must_be_http_url
-    begin
-      u = URI.parse(url)
-    rescue URI::InvalidURIError
-      errors.add(:url, 'URL が不正です．')
-      return
-    end
-
-    if !(u in URI::HTTP) || u.host.blank?
-      errors.add(:url, 'URL が不正です．')
-      return
-    end
-  end
-
-  def normalise_url
-    return if url.blank?
-
-    self.url = url.strip
-
-    u = URI.parse(url)
-    return unless u in URI::HTTP
-
-    u.host = u.host.downcase if u.host
-    u.path = u.path.sub(/\/\Z/, '') if u.path.present?
-    self.url = u.to_s
-  rescue URI::InvalidURIError
-    ;
-  end
 end

backend/app/models/post_similarity.rb

@@ -1,6 +1,4 @@
 class PostSimilarity < ApplicationRecord
-  self.primary_key = :post_id, :target_post_id
-
-  belongs_to :post
-  belongs_to :target_post, class_name: 'Post'
+  belongs_to :post, class_name: 'Post', foreign_key: 'post_id'
+  belongs_to :target_post, class_name: 'Post', foreign_key: 'target_post_id'
 end

backend/app/models/post_tag.rb

@@ -1,10 +1,6 @@
 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

backend/app/models/post_version.rb

@@ -1,38 +0,0 @@
-class PostVersion < ApplicationRecord
-  before_update do
-    raise ActiveRecord::ReadOnlyRecord, '版は更新できません．'
-  end
-
-  before_destroy do
-    raise ActiveRecord::ReadOnlyRecord, '版は削除できません．'
-  end
-
-  belongs_to :post
-  belongs_to :parent, class_name: 'Post', optional: true
-  belongs_to :created_by_user, class_name: 'User', optional: true
-
-  enum :event_type, { create: 'create',
-                      update: 'update',
-                      discard: 'discard',
-                      restore: 'restore' }, prefix: true, validate: true
-
-  validates :version_no, presence: true, numericality: { only_integer: true, greater_than: 0 }
-  validates :event_type, presence: true, inclusion: { in: event_types.keys }
-  validates :url, presence: true
-
-  validate :validate_original_created_range
-
-  scope :chronological, -> { order(:version_no, :id) }
-
-  private
-
-  def validate_original_created_range
-    f = original_created_from
-    b = original_created_before
-    return if f.blank? || b.blank?
-
-    if f >= b
-      errors.add :original_created_before, 'オリジナルの作成日時の順番がをかしぃです．'
-    end
-  end
-end

backend/app/models/tag.rb

@@ -1,119 +1,81 @@
-require 'set'
-
-
 class Tag < ApplicationRecord
-  include MyDiscard
-
-  class NicoTagNormalisationError < ArgumentError
-    ;
-  end
-
-  default_scope -> { kept }
-
-  has_many :post_tags, inverse_of: :tag
+  has_many :post_tags, dependent: :delete_all, inverse_of: :tag
   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 :tag_aliases, dependent: :destroy
 
   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', foreign_key: :tag_id, dependent: :destroy
+  has_many :reversed_nico_tag_relations, class_name: 'NicoTagRelation',
+                                         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
   has_many :children, through: :tag_implications, source: :tag
 
-  has_many :reversed_tag_implications,
-           class_name: 'TagImplication', foreign_key: :tag_id, dependent: :destroy
+  has_many :reversed_tag_implications, class_name: 'TagImplication',
+                                       foreign_key: :tag_id,
+                                       dependent: :destroy
   has_many :parents, through: :reversed_tag_implications, source: :parent_tag
 
-  has_many :tag_similarities, dependent: :delete_all
-  has_many :tag_similarities_as_target,
-           class_name: 'TagSimilarity', foreign_key: :target_tag_id, dependent: :delete_all
-
-  has_many :deerjikists, dependent: :delete_all
-  has_many :materials
-
-  belongs_to :tag_name
-  delegate :wiki_page, to: :tag_name
-
-  delegate :name, to: :tag_name, allow_nil: true
-  validates :tag_name, presence: true
-
-  enum :category, deerjikist:  'deerjikist',
+  enum :category, { deerjikist:  'deerjikist',
                     meme:        'meme',
                     character:   'character',
                     general:     'general',
                     material:    'material',
                     nico:        'nico',
-                  meta:        'meta'
+                    meta:        'meta' }
 
+  validates :name, presence: true, length: { maximum: 255 }
   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
 
-  scope :nico_tags, -> { nico }
+  scope :nico_tags, -> { where(category: :nico) }
 
   CATEGORY_PREFIXES = {
-      'general:'    => :general,
-      'gen:'        => :general,
-      'deerjikist:' => :deerjikist,
-      'djk:'        => :deerjikist,
-      'meme:'       => :meme,
-      'character:'  => :character,
-      'chr:'        => :character,
-      'material:'   => :material,
-      'mtr:'        => :material,
-      'meta:'       => :meta }.freeze
-
-  def name= val
-    (self.tag_name ||= build_tag_name).name = val
-  end
-
-  def has_wiki = wiki_page.present?
-
-  def material_id = materials.first&.id
+      'gen:'  => 'general',
+      'djk:'  => 'deerjikist',
+      'meme:' => 'meme',
+      'chr:'  => 'character',
+      'mtr:'  => 'material',
+      'meta:' => 'meta' }.freeze
 
   def self.tagme
-    @tagme ||= find_or_create_by_tag_name!('タグ希望', category: :meta)
+    @tagme ||= Tag.find_or_create_by!(name: 'タグ希望') do |tag|
+      tag.category = 'meta'
+    end
   end
 
   def self.bot
-    @bot ||= find_or_create_by_tag_name!('bot操作', category: :meta)
+    @bot ||= Tag.find_or_create_by!(name: 'bot操作') do |tag|
+      tag.category = 'meta'
+    end
   end
 
   def self.no_deerjikist
-    @no_deerjikist ||= find_or_create_by_tag_name!('ニジラー情報不詳', category: :meta)
-  end
-
-  def self.video
-    @video ||= find_or_create_by_tag_name!('動画', category: :meta)
-  end
-
-  def self.niconico
-    @niconico ||= find_or_create_by_tag_name!('ニコニコ', category: :meta)
-  end
-
-  def self.normalise_tags tag_names, with_tagme: true, deny_nico: true
-    if deny_nico && tag_names.any? { |n| n.downcase.start_with?('nico:') }
-      raise NicoTagNormalisationError
+    @no_deerjikist ||= Tag.find_or_initialize_by(name: 'ニジラー情報不詳') do |tag|
+      tag.category = 'meta'
+    end
   end
 
+  def self.normalise_tags tag_names, with_tagme: true
     tags = tag_names.map do |name|
-      pf, cat = CATEGORY_PREFIXES.find { |p, _| name.downcase.start_with?(p) } || ['', nil]
-      name = TagName.canonicalise(name.sub(/\A#{ pf }/i, '')).first
-      find_or_create_by_tag_name!(name, category: (cat || :general)).tap do |tag|
-        tag.update!(category: cat) if cat && tag.category != cat
+      pf, cat = CATEGORY_PREFIXES.find { |p, _| name.start_with?(p) } || ['', nil]
+      name.delete_prefix!(pf)
+      Tag.find_or_initialize_by(name:).tap do |tag|
+        if cat && tag.category != cat
+          tag.category = cat
+          tag.save!
+        end
       end
     end
-
     tags << Tag.tagme if with_tagme && tags.size < 10 && tags.none?(Tag.tagme)
-    tags << Tag.no_deerjikist if tags.all? { |t| !(t.deerjikist?) }
-    tags.uniq(&:id)
+    tags << Tag.no_deerjikist if tags.all? { |t| t.category != 'deerjikist' }
+    tags.uniq
   end
 
   def self.expand_parent_tags tags
@@ -139,83 +101,12 @@ class Tag < ApplicationRecord
     (result + tags).uniq { |t| t.id }
   end
 
-  def self.find_or_create_by_tag_name! name, category:
-    tn = TagName.find_undiscard_or_create_by!(name: name.to_s.strip)
-    tn = tn.canonical if tn.canonical_id?
-
-    Tag.find_undiscard_or_create_by!(tag_name_id: tn.id) do |t|
-      t.category = category
-    end
-  rescue ActiveRecord::RecordNotUnique
-    retry
-  end
-
-  def self.merge_tags! target_tag, source_tags
-    target_tag => Tag
-
-    affected_post_ids = Set.new
-
-    Tag.transaction do
-      Array(source_tags).compact.uniq.each do |source_tag|
-        source_tag => Tag
-
-        next if source_tag == target_tag
-
-        source_tag.post_tags.kept.find_each do |source_pt|
-          post_id = source_pt.post_id
-          affected_post_ids << post_id
-          source_pt.discard_by!(nil)
-          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
-
-        if source_tag_name.wiki_page.present?
-          raise ActiveRecord::RecordInvalid.new(source_tag_name)
-        end
-
-        source_tag.discard!
-
-        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
-      end
-
-      Post.where(id: affected_post_ids.to_a).find_each do |post|
-        PostVersionRecorder.record!(post:, event_type: :update, created_by_user: nil)
-      end
-
-      # 投稿件数を再集計
-      target_tag.update_columns(post_count: PostTag.kept.where(tag: target_tag).count)
-    end
-
-    target_tag.reload
-  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:')))
+    if ((category == 'nico' && !(name.start_with?('nico:'))) || 
+        (category != 'nico' && name.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
 end

backend/app/models/tag_alias.rb

@@ -0,0 +1,6 @@
+class TagAlias < ApplicationRecord
+  belongs_to :tag
+
+  validates :tag_id, presence: true
+  validates :name, presence: true, length: { maximum: 255 }, uniqueness: true
+end

backend/app/models/tag_name.rb

@@ -1,53 +0,0 @@
-class TagName < ApplicationRecord
-  include MyDiscard
-
-  default_scope -> { kept }
-
-  has_one :tag
-  has_one :wiki_page
-
-  belongs_to :canonical, class_name: 'TagName', optional: true
-  has_many :aliases, class_name: 'TagName', foreign_key: :canonical_id
-
-  validates :name, presence: true, length: { maximum: 255 }, uniqueness: true
-
-  validate :canonical_must_be_canonical
-  validate :alias_name_must_not_have_prefix
-  validate :canonical_must_not_be_present_with_tag_or_wiki_page
-  validate :name_must_be_sanitised
-
-  def self.canonicalise names
-    names = Array(names).map { |n| n.to_s.strip }.reject(&:blank?)
-    return [] if names.blank?
-
-    tns = TagName.includes(:canonical).where(name: names).index_by(&:name)
-
-    names.map { |name| tns[name]&.canonical&.name || name }.uniq
-  end
-
-  private
-
-  def canonical_must_be_canonical
-    if canonical&.canonical_id?
-      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 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 canonical_must_not_be_present_with_tag_or_wiki_page
-    if canonical_id? && (tag || wiki_page)
-      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
-
-  def name_must_be_sanitised
-    if name? && name != TagNameSanitisationRule.sanitise(name)
-      errors.add :name, '名前に使用できない文字が含まれてゐます．'
-    end
-  end
-end

backend/app/models/tag_name_sanitisation_rule.rb

@@ -1,58 +0,0 @@
-class TagNameSanitisationRule < ApplicationRecord
-  include Discard::Model
-
-  self.primary_key = :priority
-
-  default_scope -> { kept }
-
-  validates :source_pattern, presence: true, uniqueness: true
-
-  validate :source_pattern_must_be_regexp
-
-  class << self
-    def sanitise(name) =
-        rules.reduce(name.dup) { |name, (pattern, replacement)| name.gsub(pattern, replacement) }
-
-    def apply!
-      TagName.find_each do |tn|
-        name = sanitise(tn.name)
-        next if name == tn.name
-
-        TagName.transaction do
-          existing_tn = TagName.find_by(name:)
-          if existing_tn
-            existing_tn = existing_tn.canonical || existing_tn
-            next if existing_tn.id == tn.id
-
-            existing_tag = Tag.find_by(tag_name_id: existing_tn.id)
-            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
-              source_tag.update_columns(tag_name_id: existing_tn.id, updated_at: Time.current)
-            end
-            tn.discard!
-
-            next
-          end
-
-          # TagName 側の自動サニタイズを回避
-          tn.update_columns(name:, updated_at: Time.current)
-        end
-      end
-    end
-
-    private
-
-    def rules = kept.order(:priority).map { |r| [Regexp.new(r.source_pattern), r.replacement] }
-  end
-
-  private
-
-  def source_pattern_must_be_regexp
-    Regexp.new(source_pattern)
-  rescue RegexpError
-    errors.add :source_pattern, '変な正規表現だね〜（笑）'
-  end
-end

backend/app/models/tag_similarity.rb

@@ -1,6 +0,0 @@
-class TagSimilarity < ApplicationRecord
-  self.primary_key = :tag_id, :target_tag_id
-
-  belongs_to :tag
-  belongs_to :target_tag, class_name: 'Tag'
-end

backend/app/models/theatre.rb

@@ -1,13 +0,0 @@
-class Theatre < ApplicationRecord
-  include MyDiscard
-
-  has_many :comments, class_name: 'TheatreComment'
-  has_many :theatre_watching_users, dependent: :delete_all
-  has_many :active_theatre_watching_users, -> { active },
-           class_name: 'TheatreWatchingUser', inverse_of: :theatre
-  has_many :watching_users, through: :active_theatre_watching_users, source: :user
-
-  belongs_to :host_user, class_name: 'User', optional: true
-  belongs_to :current_post, class_name: 'Post', optional: true
-  belongs_to :created_by_user, class_name: 'User'
-end

backend/app/models/theatre_comment.rb

@@ -1,8 +0,0 @@
-class TheatreComment < ApplicationRecord
-  include Discard::Model
-
-  self.primary_key = :theatre_id, :no
-
-  belongs_to :theatre
-  belongs_to :user
-end

backend/app/models/theatre_watching_user.rb

@@ -1,13 +0,0 @@
-class TheatreWatchingUser < ApplicationRecord
-  self.primary_key = :theatre_id, :user_id
-
-  belongs_to :theatre
-  belongs_to :user
-
-  scope :active, -> { where('expires_at >= ?', Time.current) }
-  scope :expired, -> { where('expires_at < ?', Time.current) }
-
-  def active? = expires_at >= Time.current
-
-  def refresh! = update!(expires_at: 30.seconds.from_now)
-end

backend/app/models/user.rb

@@ -1,23 +1,29 @@
 class User < ApplicationRecord
-  enum :role, guest: 'guest', member: 'member', admin: 'admin'
+  enum :role, { guest: 'guest', member: 'member', admin: 'admin' }
 
   validates :name, length: { maximum: 255 }
   validates :inheritance_code, presence: true, length: { maximum: 64 }
   validates :role, presence: true, inclusion: { in: roles.keys }
   validates :banned, inclusion: { in: [true, false] }
 
-  has_many :created_posts,
-           class_name: 'Post', foreign_key: :uploaded_user_id, dependent: :nullify
+  has_many :posts
   has_many :settings
   has_many :user_ips, dependent: :destroy
   has_many :ip_addresses, through: :user_ips
   has_many :user_post_views, dependent: :destroy
   has_many :viewed_posts, through: :user_post_views, source: :post
-  has_many :created_wiki_pages,
-           class_name: 'WikiPage', foreign_key: :created_user_id, dependent: :nullify
-  has_many :updated_wiki_pages,
-           class_name: 'WikiPage', foreign_key: :updated_user_id, dependent: :nullify
+  has_many :created_wiki_pages, class_name: 'WikiPage', foreign_key: 'created_user_id', dependent: :nullify
+  has_many :updated_wiki_pages, class_name: 'WikiPage', foreign_key: 'updated_user_id', dependent: :nullify
 
-  def viewed?(post) = user_post_views.exists?(post_id: post.id)
-  def gte_member? = member? || admin?
+  def viewed? post
+    user_post_views.exists? post_id: post.id
+  end
+
+  def member?
+    ['member', 'admin'].include?(role)
+  end
+
+  def admin?
+    role == 'admin'
+  end
 end

backend/app/models/user_ip.rb

@@ -1,6 +1,4 @@
 class UserIp < ApplicationRecord
-  self.primary_key = :user_id, :ip_address_id
-
   belongs_to :user
   belongs_to :ip_address
 

backend/app/models/user_post_view.rb

@@ -1,6 +1,4 @@
 class UserPostView < ApplicationRecord
-  self.primary_key = :user_id, :post_id
-
   belongs_to :user
   belongs_to :post
 

backend/app/models/wiki_line.rb

@@ -1,15 +0,0 @@
-class WikiLine < ApplicationRecord
-  has_many :wiki_revision_lines, dependent: :restrict_with_exception
-
-  validates :sha256, presence: true, uniqueness: true, length: { is: 64 }
-  validates :body, presence: true
-
-  def self.upsert_by_body! body
-    sha = Digest::SHA256.hexdigest(body)
-    now = Time.current
-
-    upsert(sha256: sha, body:, created_at: now, updated_at: now)
-
-    find_by!(sha256: sha)
-  end
-end

backend/app/models/wiki_page.rb

@@ -1,56 +1,80 @@
-require 'set'
+require 'gollum-lib'
 
 
 class WikiPage < ApplicationRecord
-  include MyDiscard
+  belongs_to :tag, optional: true
+  belongs_to :created_user, class_name: 'User', foreign_key: 'created_user_id'
+  belongs_to :updated_user, class_name: 'User', foreign_key: 'updated_user_id'
 
-  default_scope -> { kept }
+  validates :title, presence: true, length: { maximum: 255 }, uniqueness: true
 
-  has_many :wiki_revisions, dependent: :destroy
-  belongs_to :created_user, class_name: 'User'
-  belongs_to :updated_user, class_name: 'User'
-
-  has_many :redirected_from_revisions,
-           class_name: 'WikiRevision',
-           foreign_key: :redirect_page_id,
-           dependent: :nullify
-
-  belongs_to :tag_name
-  validates :tag_name, presence: true
-
-  def title = tag_name.name
-
-  def title= val
-    (self.tag_name ||= build_tag_name).name = val
+  def as_json options = { }
+    self.sha = nil
+    super options
   end
 
-  def current_revision = wiki_revisions.order(id: :desc).first
+  def sha= val
+    if val.present?
+      @sha = val
+      @page = wiki.page("#{ id }.md", @sha)
+    else
+      @page = wiki.page("#{ id }.md")
+      @sha = @page.versions.first.id
+    end
+    vers = @page.versions
+    idx = vers.find_index { |ver| ver.id == @sha }
+    if idx
+      @pred = vers[idx + 1]&.id
+      @succ = idx.positive? ? vers[idx - 1].id : nil
+      @updated_at = vers[idx].authored_date
+    else
+      @sha = nil
+      @pred = nil
+      @succ = nil
+      @updated_at = nil
+    end
+    @sha
+  end
+
+  def sha
+    @sha
+  end
+
+  def pred
+    @pred
+  end
+
+  def succ
+    @succ
+  end
+
+  def updated_at
+    @updated_at
+  end
 
   def body
-    rev = current_revision
-    rev.body if rev&.content?
+    sha = nil unless @page
+    @page&.raw_data&.force_encoding('UTF-8')
   end
 
-  def resolve_redirect limit: 10
-    page = self
-    visited = Set.new
-
-    limit.times do
-      return page if visited.include?(page.id)
-
-      visited.add(page.id)
-
-      rev = page.current_revision
-      return page if !(rev&.redirect?) || !(rev.redirect_page)
-
-      page = rev.redirect_page
+  def set_body content, user:
+    commit_info = { name:   user.id.to_s,
+                    email:  'dummy@example.com' }
+    page = wiki.page("#{ id }.md")
+    if page
+      commit_info[:message] = "Updated #{ id }"
+      wiki.update_page(page, id.to_s, :markdown, content, commit_info)
+    else
+      commit_info[:message] = "Created #{ id }"
+      wiki.write_page(id.to_s, :markdown, content, commit_info)
+    end
   end
 
-    page
-  end
+  private
 
-  def pred_revision_id(revision_id) =
-      wiki_revisions.where('id < ?', revision_id).order(id: :desc).limit(1).pick(:id)
-  def succ_revision_id(revision_id) =
-      wiki_revisions.where('id > ?', revision_id).order(id: :asc).limit(1).pick(:id)
+  WIKI_PATH = Rails.root.join('wiki').to_s
+
+  def wiki
+    @wiki ||= Gollum::Wiki.new(WIKI_PATH)
+  end
 end

backend/app/models/wiki_revision.rb

@@ -1,55 +0,0 @@
-class WikiRevision < ApplicationRecord
-  belongs_to :wiki_page
-  belongs_to :base_revision, class_name: 'WikiRevision', optional: true
-  belongs_to :created_user, class_name: 'User'
-  belongs_to :redirect_page, class_name: 'WikiPage', optional: true
-
-  has_many :wiki_revision_lines, dependent: :delete_all
-  has_many :wiki_lines, through: :wiki_revision_lines
-
-  enum :kind, content: 0, redirect: 1
-
-  validates :kind, presence: true
-  validates :lines_count, numericality: { only_integer: true, greater_than_or_equal_to: 0 }
-  validates :tree_sha256, length: { is: 64 }, allow_nil: true
-
-  validate :kind_consistency
-
-  def body
-    return unless content?
-
-    wiki_revision_lines
-        .includes(:wiki_line)
-        .order(:position)
-        .map { |rev| rev.wiki_line.body }
-        .join("\n")
-  end
-
-  private
-
-  def kind_consistency
-    if content?
-      if tree_sha256.blank?
-        errors.add(:tree_sha256, '種類がページの場合は必須です．') 
-      end
-
-      if redirect_page_id.present?
-        errors.add(:redirect_page_id, '種類がページの場合は空である必要があります．')
-      end
-    end
-
-    if redirect?
-      if redirect_page_id.blank?
-        errors.add(:redirect_page_id, '種類がリダイレクトの場合は必須です．')
-      end
-
-      if tree_sha256.present?
-        errors.add(:tree_sha256, '種類がリダイレクトの場合は空である必要があります．')
-      end
-
-      if lines_count.to_i > 0
-        errors.add(:lines_count, '種類がリダイレクトの場合は 0 である必要があります．')
-      end
-    end
-  end
-end

backend/app/models/wiki_revision_line.rb

@@ -1,8 +0,0 @@
-class WikiRevisionLine < ApplicationRecord
-  belongs_to :wiki_revision
-  belongs_to :wiki_line
-
-  validates :position, presence: true,
-                       numericality: { only_integer: true, greater_than_or_equal_to: 0 }
-  validates :position, uniqueness: { scope: :wiki_revision_id }
-end

backend/app/representations/deerjikist_repr.rb

@@ -1,16 +0,0 @@
-# frozen_string_literal: true
-
-
-module DeerjikistRepr
-  BASE = { only: [:platform, :code], include: { tag: TagRepr::BASE } }.freeze
-
-  module_function
-
-  def base deerjikist
-    deerjikist.as_json(BASE)
-  end
-
-  def many deerjikists
-    deerjikists.map { |d| base(d) }
-  end
-end

backend/app/representations/material_repr.rb

@@ -1,24 +0,0 @@
-# frozen_string_literal: true
-
-
-module MaterialRepr
-  BASE = { only: [:id, :url, :created_at, :updated_at],
-           methods: [:content_type],
-           include: { tag: TagRepr::BASE,
-                      created_by_user: UserRepr::BASE,
-                      updated_by_user: UserRepr::BASE } }.freeze
-
-  module_function
-
-  def base material, host:
-    material.as_json(BASE).merge(
-        file: if material.file.attached?
-                Rails.application.routes.url_helpers.rails_storage_proxy_url(
-                    material.file, host:)
-              end)
-  end
-
-  def many materials, host:
-    materials.map { |m| base(m, host:) }
-  end
-end

backend/app/representations/post_repr.rb

@@ -1,20 +0,0 @@
-# frozen_string_literal: true
-
-
-module PostRepr
-  BASE = { include: { tags: TagRepr::BASE, uploaded_user: UserRepr::BASE } }.freeze
-
-  module_function
-
-  def base post, current_user = nil
-    json = post.as_json(BASE)
-    return json.merge(viewed: false) unless current_user
-
-    viewed = current_user.viewed?(post)
-    json.merge(viewed:)
-  end
-
-  def many posts, current_user = nil
-    posts.map { |p| base(p, current_user) }
-  end
-end

backend/app/representations/tag_repr.rb

@@ -1,17 +0,0 @@
-# frozen_string_literal: true
-
-
-module TagRepr
-  BASE = { only: [:id, :category, :post_count, :created_at, :updated_at],
-           methods: [:name, :has_wiki, :material_id] }.freeze
-
-  module_function
-
-  def base tag
-    tag.as_json(BASE)
-  end
-
-  def many tags
-    tags.map { |t| base(t) }
-  end
-end

backend/app/representations/theatre_repr.rb

@@ -1,17 +0,0 @@
-# frozen_string_literal: true
-
-
-module TheatreRepr
-  BASE = { only: [:id, :name, :opens_at, :closes_at, :created_at, :updated_at],
-           include: { created_by_user: { only: [:id, :name] } } }.freeze
-
-  module_function
-
-  def base theatre
-    theatre.as_json(BASE)
-  end
-
-  def many theatre
-    theatre.map { |t| base(t) }
-  end
-end

backend/app/representations/user_repr.rb

@@ -1,16 +0,0 @@
-# frozen_string_literal: true
-
-
-module UserRepr
-  BASE = { only: [:id, :name] }.freeze
-
-  module_function
-
-  def base user
-    user.as_json(BASE)
-  end
-
-  def many users
-    users.map { |u| base(u) }
-  end
-end

backend/app/representations/wiki_page_repr.rb

@@ -1,16 +0,0 @@
-# frozen_string_literal: true
-
-
-module WikiPageRepr
-  BASE = { methods: [:title] }.freeze
-
-  module_function
-
-  def base wiki_page
-    wiki_page.as_json(BASE)
-  end
-
-  def many wiki_pages
-    wiki_pages.map { |p| base(p) }
-  end
-end

backend/app/services/post_version_recorder.rb

@@ -1,57 +0,0 @@
-class PostVersionRecorder
-  def self.record! post:, event_type:, created_by_user:
-    new(post:, event_type:, created_by_user:).record!
-  end
-
-  def initialize post:, event_type:, created_by_user:
-    @post = post
-    @event_type = event_type
-    @created_by_user = created_by_user
-  end
-
-  def record!
-    @post.with_lock do
-      latest = @post.post_versions.order(version_no: :desc).first
-      attrs = snapshot_attributes
-
-      return latest if @event_type == :update && latest && same_snapshot?(latest, attrs)
-
-      PostVersion.create!(
-          post: @post,
-          version_no: (latest&.version_no || 0) + 1,
-          event_type: @event_type,
-          title: attrs[:title],
-          url: attrs[:url],
-          thumbnail_base: attrs[:thumbnail_base],
-          tags: attrs[:tags],
-          parent: attrs[:parent],
-          original_created_from: attrs[:original_created_from],
-          original_created_before: attrs[:original_created_before],
-          created_at: Time.current,
-          created_by_user: @created_by_user)
-    end
-  end
-
-  private
-
-  def snapshot_attributes
-    { title: @post.title,
-      url: @post.url,
-      thumbnail_base: @post.thumbnail_base,
-      tags: @post.snapshot_tag_names.join(' '),
-      parent: @post.parent,
-      original_created_from: @post.original_created_from,
-      original_created_before: @post.original_created_before }
-  end
-
-  def same_snapshot? version, attrs
-    true &&
-        version.title == attrs[:title] &&
-        version.url == attrs[:url] &&
-        version.thumbnail_base == attrs[:thumbnail_base] &&
-        version.tags == attrs[:tags] &&
-        version.parent_id == attrs[:parent]&.id &&
-        version.original_created_from == attrs[:original_created_from] &&
-        version.original_created_before == attrs[:original_created_before]
-  end
-end

backend/app/services/similarity/calc.rb

@@ -1,106 +0,0 @@
-module Similarity
-  class Calc
-    def self.call model, tgt
-      similarity_model = "#{ model.name }Similarity".constantize
-
-      # 最大保存件数
-      n = 20
-
-      similarity_model.delete_all
-
-      posts = model.includes(tgt).select(:id).to_a
-
-      tag_ids = { }
-      tag_cnts = { }
-
-      posts.each do |p|
-        arr = p.public_send(tgt).map(&:id).sort
-        tag_ids[p.id] = arr
-        tag_cnts[p.id] = arr.size
-      end
-
-      intersection_size = -> a, b do
-        i = 0
-        j = 0
-        cnt = 0
-        while i < a.size && j < b.size
-          a_i = a[i]
-          b_j = b[j]
-          if a_i == b_j
-            cnt += 1
-            i += 1
-            j += 1
-          elsif a_i < b_j
-            i += 1
-          else
-            j += 1
-          end
-        end
-        cnt
-      end
-
-      push_topk = -> list, cos, target_id do
-        return if list.size >= n && cos <= list[-1][0]
-
-        idx = nil
-        list.each_with_index do |(c, tid), i|
-          if tid == target_id
-            idx = i
-            break
-          end
-        end
-        if idx
-          return if cos <= list[idx][0]
-          list.delete_at(idx)
-        end
-
-        insert_at = list.size
-        list.each_with_index do |(c, _), i|
-          if cos > c
-            insert_at = i
-            break
-          end
-        end
-        list.insert(insert_at, [cos, target_id])
-        list.pop if list.size > n
-      end
-
-      top = Hash.new { |h, key| h[key] = [] }
-
-      ids = posts.map(&:id)
-      ids.each_with_index do |post_id, i|
-        a = tag_ids[post_id]
-        a_cnt = tag_cnts[post_id]
-
-        ((i + 1)...ids.size).each do |j|
-          target_id = ids[j]
-          b = tag_ids[target_id]
-          b_cnt = tag_cnts[target_id]
-
-          norm = Math.sqrt(a_cnt * b_cnt)
-          cos = norm.zero? ? 0.0 : intersection_size.(a, b).fdiv(norm)
-
-          push_topk.(top[post_id], cos, target_id)
-          push_topk.(top[target_id], cos, post_id)
-        end
-      end
-
-      buf = []
-      flush = -> do
-        return if buf.empty?
-        similarity_model.insert_all!(buf)
-        buf.clear
-      end
-
-      top.each do |post_id, list|
-        list.each do |cos, target_post_id|
-          buf << { "#{ model.name.underscore }_id".to_sym => post_id,
-                   "target_#{ model.name.underscore }_id".to_sym => target_post_id,
-                   cos: }
-          flush.call if buf.size >= 1_000
-        end
-      end
-      flush.call
-    end
-  end
-end

backend/app/services/wiki/commit.rb

@@ -1,122 +0,0 @@
-require 'digest'
-
-
-module Wiki
-  class Commit
-    class Conflict < StandardError
-      ;
-    end
-
-    def self.content! page:, body:, created_user:, message: nil, base_revision_id: nil
-      new(page:, created_user:).content!(body:, message:, base_revision_id:)
-    end
-
-    def self.redirect! page:, redirect_page:, created_user:, message: nil, base_revision_id: nil
-      new(page:, created_user:).redirect!(redirect_page:, message:, base_revision_id:)
-    end
-
-    def initialize page:, created_user:
-      @page = page
-      @created_user = created_user
-    end
-
-    def content! body:, message:, base_revision_id:
-      normalised = normalise_body(body)
-      lines = split_lines(normalised)
-
-      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!
-
-        if base_revision_id.present?
-          current_id = @page.wiki_revisions.maximum(:id)
-          if current_id && current_id != base_revision_id.to_i
-            raise 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
-
-        rev = WikiRevision.create!(
-            wiki_page:        @page,
-            base_revision_id:,
-            created_user:     @created_user,
-            kind:             :content,
-            redirect_page_id: nil,
-            message:,
-            lines_count:      lines.length,
-            tree_sha256:      tree_sha)
-
-        rows = line_ids.each_with_index.map do |line_id, pos|
-          { wiki_revision_id: rev.id, wiki_line_id: line_id, position: pos }
-        end
-        WikiRevisionLine.insert_all!(rows)
-
-        rev
-      end
-    end
-
-    def redirect! redirect_page:, message:, base_revision_id:
-      ActiveRecord::Base.transaction do
-        @page.lock!
-
-        if base_revision_id.present?
-          current_id = @page.wiki_revisions.maximum(:id)
-          if current_id && current_id != base_revision_id.to_i
-            raise 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
-
-        WikiRevision.create!(
-            wiki_page:        @page,
-            base_revision_id:,
-            created_user:     @created_user,
-            kind:             :redirect,
-            redirect_page:,
-            message:,
-            lines_count:      0,
-            tree_sha256:      nil)
-      end
-    end
-
-    private
-
-    def normalise_body body
-      s = body.to_s
-      s.gsub!("\r\n", "\n")
-      s.encode('UTF-8', invalid: :replace, undef: :replace, replace: '🖕')
-    end
-
-    def split_lines body
-      body.split("\n")
-    end
-
-    def upsert_lines! lines, line_shas
-      now = Time.current
-
-      id_by_sha = WikiLine.where(sha256: line_shas).pluck(:sha256, :id).to_h
-
-      missing_rows = []
-      line_shas.each_with_index do |sha, i|
-        next if id_by_sha.key?(sha)
-
-        missing_rows << { sha256:     sha,
-                          body:       lines[i],
-                          created_at: now,
-                          updated_at: now }
-      end
-
-      if missing_rows.any?
-        WikiLine.upsert_all(missing_rows)
-        id_by_sha = WikiLine.where(sha256: line_shas).pluck(:sha256, :id).to_h
-      end
-
-      id_by_sha
-    end
-  end
-end

backend/config/application.rb

@@ -11,9 +11,6 @@ module Backend
     # Initialize configuration defaults for originally generated Rails version.
     config.load_defaults 8.0
 
-    config.i18n.available_locales = [:ja, :en]
-    config.i18n.default_locale = :ja
-
     # Please, add to the `ignore` list any other `lib` subdirectories that do
     # not contain `.rb` files, or that should not be reloaded or eager loaded.
     # Common ones are `templates`, `generators`, or `middleware`, for example.

backend/config/environments/production.rb

@@ -18,7 +18,8 @@ Rails.application.configure do
   # Enable serving of images, stylesheets, and JavaScripts from an asset server.
   # config.asset_host = "http://assets.example.com"
 
-  config.active_storage.service = :r2
+  # Store uploaded files on the local file system (see config/storage.yml for options).
+  config.active_storage.service = :local
 
   # Assume all access to the app is happening through a SSL-terminating reverse proxy.
   config.assume_ssl = true

backend/config/environments/test.rb

@@ -50,6 +50,4 @@ Rails.application.configure do
 
   # Raise error when a before_action's only/except options reference missing actions.
   config.action_controller.raise_on_missing_callback_actions = true
-
-  Rails.application.routes.default_url_options[:host] = 'www.example.com'
 end

backend/config/locales/en.yml

@@ -28,8 +28,4 @@
 #       enabled: "ON"
 
 en:
-  activerecord:
-    errors:
-      messages:
-        record_invalid: "Validation failed: %{errors}"
-        taken: 'イキスギ!'
+  hello: "Hello world"

backend/config/locales/ja.yml

@@ -1,2 +0,0 @@
-ja:
-  hello: 'ぬ゛〜゛ん゛'

backend/config/routes.rb

@@ -1,25 +1,10 @@
 Rails.application.routes.draw do
   resources :nico_tags, path: 'tags/nico', only: [:index, :update]
 
-  scope 'tags/:parent_id/children', controller: :tag_children do
-    post ':child_id', action: :create
-    delete ':child_id', action: :destroy
-  end
-
-  resources :tags, only: [:index, :show, :update] do
+  resources :tags do
     collection do
       get :autocomplete
-      get :'with-depth', action: :with_depth
-
-      scope :name do
-        get ':name/deerjikists', action: :deerjikists_by_name
-        get ':name/materials', action: :materials_by_name
-        get ':name', action: :show_by_name
-      end
-    end
-
-    member do
-      get :deerjikists
+      get 'name/:name', action: :show_by_name
     end
   end
 
@@ -45,7 +30,7 @@ Rails.application.routes.draw do
     end
   end
 
-  resources :posts, only: [:index, :show, :create, :update] do
+  resources :posts do
     collection do
       get :random
       get :changes
@@ -65,24 +50,11 @@ Rails.application.routes.draw do
     end
   end
 
-  resources :deerjikists, only: [] do
-    collection do
-      scope ':platform/:code' do
-        get '', action: :show
-        put '', action: :update
-        delete '', action: :destroy
-      end
-    end
-  end
-
-  resources :theatres, only: [:show] do
-    member do
-      put :watching
-      patch :next_post
-    end
-
-    resources :comments, controller: :theatre_comments, only: [:index, :create]
-  end
-
-  resources :materials, only: [:index, :show, :create, :update, :destroy]
+  resources :ip_addresses
+  resources :nico_tag_relations
+  resources :post_tags
+  resources :settings
+  resources :tag_aliases
+  resources :user_ips
+  resources :user_post_views
 end

backend/config/storage.yml

@@ -6,10 +6,29 @@ local:
   service: Disk
   root: <%= Rails.root.join("storage") %>
 
-r2:
-  service: S3
-  endpoint: <%= ENV['R2_ENDPOINT'] %>
-  access_key_id: <%= ENV['R2_ACCESS_KEY_ID'] %>
-  secret_access_key: <%= ENV['R2_SECRET_ACCESS_KEY'] %>
-  bucket: <%= ENV['R2_BUCKET'] %>
-  region: auto
+# Use bin/rails credentials:edit to set the AWS secrets (as aws:access_key_id|secret_access_key)
+# amazon:
+#   service: S3
+#   access_key_id: <%= Rails.application.credentials.dig(:aws, :access_key_id) %>
+#   secret_access_key: <%= Rails.application.credentials.dig(:aws, :secret_access_key) %>
+#   region: us-east-1
+#   bucket: your_own_bucket-<%= Rails.env %>
+
+# Remember not to checkin your GCS keyfile to a repository
+# google:
+#   service: GCS
+#   project: your_project
+#   credentials: <%= Rails.root.join("path/to/gcs.keyfile") %>
+#   bucket: your_own_bucket-<%= Rails.env %>
+
+# Use bin/rails credentials:edit to set the Azure Storage secret (as azure_storage:storage_access_key)
+# microsoft:
+#   service: AzureStorage
+#   storage_account_name: your_account_name
+#   storage_access_key: <%= Rails.application.credentials.dig(:azure_storage, :storage_access_key) %>
+#   container: your_container_name-<%= Rails.env %>
+
+# mirror:
+#   service: Mirror
+#   primary: local
+#   mirrors: [ amazon, google, microsoft ]

backend/db/migrate/20251229012100_remove_tag_from_wiki_pages.rb

@@ -1,5 +0,0 @@
-class RemoveTagFromWikiPages < ActiveRecord::Migration[7.0]
-  def change
-    remove_reference :wiki_pages, :tag, if_exists: true
-  end
-end

backend/db/migrate/20251229020700_create_wiki_lines.rb

@@ -1,11 +0,0 @@
-class CreateWikiLines < ActiveRecord::Migration[7.0]
-  def change
-    create_table :wiki_lines do |t|
-      t.string :sha256, null: false, limit: 64
-      t.text :body, null: false
-      t.timestamps
-    end
-
-    add_index :wiki_lines, :sha256, unique: true
-  end
-end

backend/db/migrate/20251229021000_create_wiki_revisions.rb

@@ -1,19 +0,0 @@
-class CreateWikiRevisions < ActiveRecord::Migration[7.0]
-  def change
-    create_table :wiki_revisions do |t|
-      t.references :wiki_page, null: false, foreign_key: true
-      t.references :base_revision, foreign_key: { to_table: :wiki_revisions }
-      t.references :created_user, null: false, foreign_key: { to_table: :users }
-      t.integer :kind, null: false, default: 0  # 0: content, 1: redirect
-      t.references :redirect_page, foreign_key: { to_table: :wiki_pages }
-      t.string :message
-      t.integer :lines_count, null: false, default: 0
-      t.string :tree_sha256, limit: 64
-      t.timestamps
-    end
-
-    add_index :wiki_revisions, :tree_sha256
-    add_index :wiki_revisions, [:wiki_page_id, :id]
-    add_index :wiki_revisions, :kind
-  end
-end

backend/db/migrate/20251229022100_create_wiki_revision_lines.rb

@@ -1,12 +0,0 @@
-class CreateWikiRevisionLines < ActiveRecord::Migration[7.0]
-  def change
-    create_table :wiki_revision_lines do |t|
-      t.references :wiki_revision, null: false, foreign_key: true
-      t.integer :position, null: false
-      t.references :wiki_line, null: false, foreign_key: true
-    end
-
-    add_index :wiki_revision_lines, [:wiki_revision_id, :position], unique: true
-    add_index :wiki_revision_lines, [:wiki_revision_id, :wiki_line_id]
-  end
-end

backend/db/migrate/20251230143400_make_thumbnail_base_nullable_in_posts.rb

@@ -1,27 +0,0 @@
-class MakeThumbnailBaseNullableInPosts < ActiveRecord::Migration[7.0]
-  def up
-    change_column_null :posts, :thumbnail_base, true
-
-    execute <<~SQL
-      UPDATE
-        posts
-      SET
-        thumbnail_base = NULL
-      WHERE
-        thumbnail_base = ''
-    SQL
-  end
-
-  def down
-    execute <<~SQL
-      UPDATE
-        posts
-      SET
-        thumbnail_base = ''
-      WHERE
-        thumbnail_base IS NULL
-    SQL
-
-    change_column_null :posts, :thumbnail_base, false
-  end
-end

backend/db/migrate/20260107034300_make_title_nullable_in_posts.rb

@@ -1,28 +0,0 @@
-class MakeTitleNullableInPosts < ActiveRecord::Migration[7.0]
-  def up
-    change_column_null :posts, :title, true
-
-    execute <<~SQL
-      UPDATE
-        posts
-      SET
-        title = NULL
-      WHERE
-        title = ''
-    SQL
-  end
-
-  def down
-    execute <<~SQL
-      UPDATE
-        posts
-      SET
-        title = ''
-      WHERE
-        title IS NULL
-    SQL
-
-    change_column_null :posts, :title, false
-  end
-end
-

backend/db/migrate/20260111180600_create_tag_names.rb

@@ -1,10 +0,0 @@
-class CreateTagNames < ActiveRecord::Migration[7.0]
-  def change
-    create_table :tag_names do |t|
-      t.string :name, limit: 255, null: false
-      t.references :canonical, null: true, foreign_key: { to_table: :tag_names }, index: true
-      t.timestamps
-    end
-    add_index :tag_names, :name, unique: true
-  end
-end

backend/db/migrate/20260111192600_add_tag_name_to_tags.rb

@@ -1,42 +0,0 @@
-class AddTagNameToTags < ActiveRecord::Migration[7.0]
-  class Tag < ApplicationRecord
-    self.table_name = 'tags'
-  end
-
-  class TagName < ApplicationRecord
-    self.table_name = 'tag_names'
-  end
-
-  def up
-    add_reference :tags, :tag_name, null: true, foreign_key: true, index: false, after: :id
-    add_index :tags, :tag_name_id, unique: true
-
-    Tag.find_each do |tag|
-      name = tag.read_attribute(:name)
-      tn = TagName.find_or_create_by!(name:) do |r|
-        r.canonical_id = nil
-      end
-      tag.update_columns(tag_name_id: tn.id)
-    end
-
-    change_column_null :tags, :tag_name_id, false
-
-    remove_column :tags, :name
-  end
-
-  def down
-    add_column :tags, :name, :string, limit: 255, null: true, after: :id
-
-    Tag.find_each do |tag|
-      tag_name_id = tag.read_attribute(:tag_name_id)
-      name = TagName.find(tag_name_id).read_attribute(:name)
-      tag.update_columns(name:)
-    end
-
-    change_column_null :tags, :name, false
-
-    remove_foreign_key :tags, column: :tag_name_id
-    remove_index :tags, :tag_name_id
-    remove_column :tags, :tag_name_id
-  end
-end

backend/db/migrate/20260111204400_add_tag_name_to_wiki_pages.rb

@@ -1,42 +0,0 @@
-class AddTagNameToWikiPages < ActiveRecord::Migration[7.0]
-  class WikiPage < ApplicationRecord
-    self.table_name = 'wiki_pages'
-  end
-
-  class TagName < ApplicationRecord
-    self.table_name = 'tag_names'
-  end
-
-  def up
-    add_reference :wiki_pages, :tag_name, null: true, foreign_key: true, index: false, after: :id
-    add_index :wiki_pages, :tag_name_id, unique: true
-
-    WikiPage.find_each do |page|
-      name = page.read_attribute(:title)
-      tn = TagName.find_or_create_by!(name:) do |r|
-        r.canonical_id = nil
-      end
-      page.update_columns(tag_name_id: tn.id)
-    end
-
-    change_column_null :wiki_pages, :tag_name_id, false
-
-    remove_column :wiki_pages, :title
-  end
-
-  def down
-    add_column :wiki_pages, :title, :string, limit: 255, null: true, after: :id
-
-    WikiPage.find_each do |page|
-      tag_name_id = page.read_attribute(:tag_name_id)
-      title = TagName.find(tag_name_id).read_attribute(:name)
-      page.update_columns(title:)
-    end
-
-    change_column_null :wiki_pages, :title, false
-
-    remove_foreign_key :wiki_pages, column: :tag_name_id
-    remove_index :wiki_pages, :tag_name_id
-    remove_column :wiki_pages, :tag_name_id
-  end
-end

backend/db/migrate/20260112111800_drop_tag_aliases.rb

@@ -1,9 +0,0 @@
-class DropTagAliases < ActiveRecord::Migration[7.0]
-  def up
-    drop_table :tag_aliases
-  end
-
-  def down
-    raise ActiveRecord::IrreversibleMigration, '戻せません．'
-  end
-end

backend/db/migrate/20260118144400_add_unique_index_to_url_in_posts.rb

@@ -1,6 +0,0 @@
-class AddUniqueIndexToUrlInPosts < ActiveRecord::Migration[7.1]
-  def change
-    change_column :posts, :url, :string, limit: 768
-    add_index :posts, :url, unique: true, name: 'index_posts_on_url'
-  end
-end

backend/db/migrate/20260121024000_change_post_similarities_to_composite_pk.rb

@@ -1,43 +0,0 @@
-class ChangePostSimilaritiesToCompositePk < ActiveRecord::Migration[8.0]
-  def up
-    execute <<~SQL
-      ALTER TABLE
-        post_similarities
-          MODIFY COLUMN id BIGINT NOT NULL
-      ;
-    SQL
-
-    execute <<~SQL
-      ALTER TABLE
-        post_similarities
-          DROP PRIMARY KEY
-      ;
-    SQL
-
-    remove_column :post_similarities, :id
-
-    execute <<~SQL
-      ALTER TABLE
-        post_similarities
-          ADD PRIMARY KEY (post_id, target_post_id)
-      ;
-    SQL
-  end
-
-  def down
-    execute <<~SQL
-      ALTER TABLE
-        post_similarities
-          DROP PRIMARY KEY
-      ;
-    SQL
-
-    execute <<~SQL
-      ALTER TABLE
-        post_similarities
-          ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT FIRST
-        , ADD PRIMARY KEY (id)
-      ;
-    SQL
-  end
-end

backend/db/migrate/20260121024800_change_tag_similarities_to_composite_pk.rb

@@ -1,43 +0,0 @@
-class ChangeTagSimilaritiesToCompositePk < ActiveRecord::Migration[8.0]
-  def up
-    execute <<~SQL
-      ALTER TABLE
-        tag_similarities
-          MODIFY COLUMN id BIGINT NOT NULL
-      ;
-    SQL
-
-    execute <<~SQL
-      ALTER TABLE
-        tag_similarities
-          DROP PRIMARY KEY
-      ;
-    SQL
-
-    remove_column :tag_similarities, :id
-
-    execute <<~SQL
-      ALTER TABLE
-        tag_similarities
-          ADD PRIMARY KEY (tag_id, target_tag_id)
-      ;
-    SQL
-  end
-
-  def down
-    execute <<~SQL
-      ALTER TABLE
-        tag_similarities
-          DROP PRIMARY KEY
-      ;
-    SQL
-
-    execute <<~SQL
-      ALTER TABLE
-        tag_similarities
-          ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT FIRST
-        , ADD PRIMARY KEY (id)
-      ;
-    SQL
-  end
-end

backend/db/migrate/20260121213900_add_index_to_post_similarities.rb

@@ -1,9 +0,0 @@
-class AddIndexToPostSimilarities < ActiveRecord::Migration[8.0]
-  def change
-    remove_index :post_similarities, name: 'index_post_similarities_on_post_id'
-
-    add_index :post_similarities, [:post_id, :cos],
-              order: { cos: :desc },
-              name: 'index_post_similarities_on_post_id_and_cos'
-  end
-end

backend/db/migrate/20260121225600_add_index_to_tag_similarities.rb

@@ -1,9 +0,0 @@
-class AddIndexToTagSimilarities < ActiveRecord::Migration[8.0]
-  def change
-    remove_index :tag_similarities, name: 'index_tag_similarities_on_tag_id'
-
-    add_index :tag_similarities, [:tag_id, :cos],
-              order: { cos: :desc },
-              name: 'index_tag_similarities_on_tag_id_and_cos'
-  end
-end

backend/db/migrate/20260126124100_add_unique_index_to_ip_addresses.rb

@@ -1,5 +0,0 @@
-class AddUniqueIndexToIpAddresses < ActiveRecord::Migration[8.0]
-  def change
-    add_index :ip_addresses, :ip_address, unique: true, name: 'index_ip_addresses_on_ip_address'
-  end
-end

backend/db/migrate/20260127000900_change_user_ips_to_composite_pk.rb

@@ -1,47 +0,0 @@
-class ChangeUserIpsToCompositePk < ActiveRecord::Migration[8.0]
-  def up
-    execute <<~SQL
-      ALTER TABLE
-        user_ips
-          MODIFY COLUMN id BIGINT NOT NULL
-      ;
-    SQL
-
-    execute <<~SQL
-      ALTER TABLE
-        user_ips
-          DROP PRIMARY KEY
-      ;
-    SQL
-
-    remove_column :user_ips, :id
-
-    execute <<~SQL
-      ALTER TABLE
-        user_ips
-          ADD PRIMARY KEY (user_id, ip_address_id)
-      ;
-    SQL
-
-    remove_index :user_ips, name: 'index_user_ips_on_user_id'
-  end
-
-  def down
-    execute <<~SQL
-      ALTER TABLE
-        user_ips
-          DROP PRIMARY KEY
-      ;
-    SQL
-
-    execute <<~SQL
-      ALTER TABLE
-        user_ips
-          ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT FIRST
-        , ADD PRIMARY KEY (id)
-      ;
-    SQL
-
-    add_index :user_ips, :user_id, name: 'index_user_ips_on_user_id'
-  end
-end

backend/db/migrate/20260127005300_change_user_post_views_to_composite_pk.rb

@@ -1,47 +0,0 @@
-class ChangeUserPostViewsToCompositePk < ActiveRecord::Migration[8.0]
-  def up
-    execute <<~SQL
-      ALTER TABLE
-        user_post_views
-          MODIFY COLUMN id BIGINT NOT NULL
-      ;
-    SQL
-
-    execute <<~SQL
-      ALTER TABLE
-        user_post_views
-          DROP PRIMARY KEY
-      ;
-    SQL
-
-    remove_column :user_post_views, :id
-
-    execute <<~SQL
-      ALTER TABLE
-        user_post_views
-          ADD PRIMARY KEY (user_id, post_id)
-      ;
-    SQL
-
-    remove_index :user_post_views, name: 'index_user_post_views_on_user_id'
-  end
-
-  def down
-    execute <<~SQL
-      ALTER TABLE
-        user_post_views
-          DROP PRIMARY KEY
-      ;
-    SQL
-
-    execute <<~SQL
-      ALTER TABLE
-        user_post_views
-          ADD COLUMN id BIGINT NOT NULL AUTO_INCREMENT FIRST
-        , ADD PRIMARY KEY (id)
-      ;
-    SQL
-
-    add_index :user_post_views, :user_id, name: 'index_user_post_views_on_user_id'
-  end
-end

backend/db/migrate/20260303122700_create_deerjikists.rb

@@ -1,10 +0,0 @@
-class CreateDeerjikists < ActiveRecord::Migration[8.0]
-  def change
-    create_table :deerjikists, primary_key: [:platform, :code] do |t|
-      t.string :platform, null: false, limit: 16
-      t.string :code, null: false
-      t.references :tag, null: false
-      t.timestamps
-    end
-  end
-end

backend/db/migrate/20260309123200_create_tag_name_sanitisation_rules.rb

@@ -1,31 +0,0 @@
-class CreateTagNameSanitisationRules < ActiveRecord::Migration[8.0]
-  def up
-    create_table :tag_name_sanitisation_rules, id: :integer, primary_key: :priority do |t|
-      t.string :source_pattern, null: false
-      t.string :replacement, null: false
-      t.timestamps
-      t.datetime :discarded_at
-      t.index :source_pattern, unique: true
-      t.index :discarded_at
-    end
-
-    now = ActiveRecord::Base.connection.quote(Time.current)
-    execute <<~SQL
-      INSERT INTO
-        tag_name_sanitisation_rules(priority, source_pattern, replacement, created_at, updated_at)
-      VALUES
-        (10, '\\\\*',           '_',         #{ now }, #{ now })
-      , (20, '\\\\?',           '_',         #{ now }, #{ now })
-      , (25, '\\\\/',           '_',         #{ now }, #{ now })
-      , (30, '_+',              '_',         #{ now }, #{ now })
-      , (40, '_$',              '',          #{ now }, #{ now })
-      , (45, '^([^:]+\\\\:)?_', '\\\\1',     #{ now }, #{ now })
-      , (50, '^([^:]+\\\\:)?$', '\\\\1null', #{ now }, #{ now })
-      ;
-    SQL
-  end
-
-  def down
-    drop_table :tag_name_sanitisation_rules
-  end
-end

backend/db/migrate/20260311123100_add_discarded_at_to_tags.rb

@@ -1,6 +0,0 @@
-class AddDiscardedAtToTags < ActiveRecord::Migration[8.0]
-  def change
-    add_column :tags, :discarded_at, :datetime
-    add_index :tags, :discarded_at
-  end
-end

backend/db/migrate/20260311232100_add_discarded_at_to_tag_names.rb

@@ -1,6 +0,0 @@
-class AddDiscardedAtToTagNames < ActiveRecord::Migration[8.0]
-  def change
-    add_column :tag_names, :discarded_at, :datetime
-    add_index :tag_names, :discarded_at
-  end
-end

backend/db/migrate/20260311232300_add_discarded_at_to_wiki_pages.rb

@@ -1,6 +0,0 @@
-class AddDiscardedAtToWikiPages < ActiveRecord::Migration[8.0]
-  def change
-    add_column :wiki_pages, :discarded_at, :datetime
-    add_index :wiki_pages, :discarded_at
-  end
-end

backend/db/migrate/20260316082500_create_theatres.rb

@@ -1,17 +0,0 @@
-class CreateTheatres < ActiveRecord::Migration[8.0]
-  def change
-    create_table :theatres do |t|
-      t.string :name
-      t.datetime :opens_at, null: false, index: true
-      t.datetime :closes_at, index: true
-      t.integer :kind, null: false, index: true
-      t.references :current_post, foreign_key: { to_table: :posts }, index: true
-      t.datetime :current_post_started_at
-      t.integer :next_comment_no, null: false, default: 1
-      t.references :host_user, foreign_key: { to_table: :users }
-      t.references :created_by_user, null: false, foreign_key: { to_table: :users }, index: true
-      t.timestamps
-      t.datetime :discarded_at, index: true
-    end
-  end
-end

backend/db/migrate/20260316083500_create_theatre_comments.rb

@@ -1,12 +0,0 @@
-class CreateTheatreComments < ActiveRecord::Migration[8.0]
-  def change
-    create_table :theatre_comments, primary_key: [:theatre_id, :no] do |t|
-      t.references :theatre, null: false, foreign_key: { to_table: :theatres }
-      t.integer :no, null: false
-      t.references :user, foreign_key: { to_table: :users }
-      t.text :content, null: false
-      t.timestamps
-      t.datetime :discarded_at, index: true
-    end
-  end
-end

backend/db/migrate/20260317015000_create_theatre_watching_users.rb

@@ -1,12 +0,0 @@
-class CreateTheatreWatchingUsers < ActiveRecord::Migration[8.0]
-  def change
-    create_table :theatre_watching_users, primary_key: [:theatre_id, :user_id] do |t|
-      t.references :theatre, null: false, foreign_key: { to_table: :theatres }
-      t.references :user, null: false, foreign_key: { to_table: :users }, index: true
-      t.datetime :expires_at, null: false, index: true
-      t.timestamps
-
-      t.index [:theatre_id, :expires_at]
-    end
-  end
-end

backend/db/migrate/20260329034700_create_materials.rb

@@ -1,34 +0,0 @@
-class CreateMaterials < ActiveRecord::Migration[8.0]
-  def change
-    create_table :materials do |t|
-      t.string :url
-      t.references :parent, index: true, foreign_key: { to_table: :materials }
-      t.references :tag, index: true, foreign_key: true
-      t.references :created_by_user, foreign_key: { to_table: :users }
-      t.references :updated_by_user, foreign_key: { to_table: :users }
-      t.timestamps
-      t.datetime :discarded_at, index: true
-      t.virtual :active_url, type: :string,
-                             as: 'IF(discarded_at IS NULL, url, NULL)',
-                             stored: false
-
-      t.index :active_url, unique: true
-    end
-
-    create_table :material_versions do |t|
-      t.references :material, null: false, foreign_key: true
-      t.integer :version_no, null: false
-      t.string :url, index: true
-      t.references :parent, index: true, foreign_key: { to_table: :materials }
-      t.references :tag, index: true, foreign_key: true
-      t.references :created_by_user, foreign_key: { to_table: :users }
-      t.references :updated_by_user, foreign_key: { to_table: :users }
-      t.timestamps
-      t.datetime :discarded_at, index: true
-
-      t.index [:material_id, :version_no],
-              unique: true,
-              name: 'index_material_versions_on_material_id_and_version_no'
-    end
-  end
-end

backend/db/migrate/20260409123700_create_post_versions.rb

@@ -1,203 +0,0 @@
-require 'set'
-
-
-class CreatePostVersions < ActiveRecord::Migration[8.0]
-  class Post < ApplicationRecord
-    self.table_name = 'posts'
-  end
-
-  class PostTag < ApplicationRecord
-    self.table_name = 'post_tags'
-  end
-
-  class PostVersion < ApplicationRecord
-    self.table_name = 'post_versions'
-  end
-
-  def up
-    create_table :post_versions do |t|
-      t.references :post, null: false, foreign_key: true
-      t.integer :version_no, null: false
-      t.string :event_type, null: false
-      t.string :title
-      t.string :url, limit: 768, null: false
-      t.string :thumbnail_base, limit: 2000
-      t.text :tags, null: false
-      t.references :parent, foreign_key: { to_table: :posts }
-      t.datetime :original_created_from
-      t.datetime :original_created_before
-      t.datetime :created_at, null: false
-      t.references :created_by_user, foreign_key: { to_table: :users }
-
-      t.index [:post_id, :version_no], unique: true
-      t.check_constraint 'version_no > 0',
-                         name: 'post_versions_version_no_positive'
-      t.check_constraint "event_type IN ('create', 'update', 'discard', 'restore')",
-                         name: 'post_versions_event_type_valid'
-    end
-
-    PostVersion.reset_column_information
-
-    say_with_time 'Backfilling post_versions' do
-      Post.find_in_batches(batch_size: 500) do |posts|
-        post_ids = posts.map(&:id)
-
-        post_tag_rows_by_post_id =
-            PostTag
-            .joins('INNER JOIN tags ON tags.id = post_tags.tag_id')
-            .joins('INNER JOIN tag_names ON tag_names.id = tags.tag_name_id')
-            .where(post_id: post_ids)
-            .pluck('post_tags.post_id',
-                   'post_tags.created_at',
-                   'post_tags.discarded_at',
-                   'post_tags.created_user_id',
-                   'post_tags.deleted_user_id',
-                   'tag_names.name')
-            .each_with_object(Hash.new { |h, k| h[k] = [] }) do |row, h|
-              post_id, created_at, discarded_at, created_user_id, deleted_user_id, tag_name = row
-              h[post_id] << { created_at:,
-                              discarded_at:,
-                              created_user_id:,
-                              deleted_user_id:,
-                              tag_name: }
-            end
-
-        rows = []
-
-        posts.each do |post|
-          post_tag_rows = post_tag_rows_by_post_id[post.id]
-
-          events = post_tag_rows.flat_map do |post_tag_row|
-            ary = [[post_tag_row[:created_at],
-                    post_tag_row[:created_user_id],
-                    :add,
-                    post_tag_row[:tag_name]]]
-
-            if post_tag_row[:discarded_at]
-              ary << [post_tag_row[:discarded_at],
-                      post_tag_row[:deleted_user_id],
-                      :remove,
-                      post_tag_row[:tag_name]]
-            end
-
-            ary
-          end
-
-          kind_order = { add: 0, remove: 1 }
-
-          events.sort_by! do |event_at, user_id, kind, tag_name|
-            [event_at, user_id || 0, kind_order.fetch(kind), tag_name]
-          end
-
-          event_buckets = bucket_events(events)
-
-          active_tags = Set.new
-          version_no = 0
-
-          if event_buckets.empty?
-            version_no += 1
-            rows << build_row(post:,
-                              version_no:,
-                              event_type: 'create',
-                              created_at: post.created_at,
-                              created_by_user_id: post.uploaded_user_id,
-                              tags: [])
-            next
-          end
-
-          first_bucket = event_buckets.first
-          merge_first_bucket_into_create = first_bucket[:first_at] <= post.created_at + 1.second
-
-          if merge_first_bucket_into_create
-            event_buckets.shift
-            apply_bucket!(active_tags, first_bucket)
-
-            version_no += 1
-            rows << build_row(
-                post:,
-                version_no:,
-                event_type: 'create',
-                created_at: post.created_at,
-                created_by_user_id: post.uploaded_user_id || first_bucket[:user_ids].compact.first,
-                tags: active_tags.to_a.sort)
-          else
-            version_no += 1
-            rows << build_row(
-                post:,
-                version_no:,
-                event_type: 'create',
-                created_at: post.created_at,
-                created_by_user_id: post.uploaded_user_id,
-                tags: [])
-          end
-
-          event_buckets.each do |bucket|
-            apply_bucket!(active_tags, bucket)
-
-            version_no += 1
-            rows << build_row(
-                post:,
-                version_no:,
-                event_type: 'update',
-                created_at: bucket[:first_at],
-                created_by_user_id: bucket[:user_ids].compact.first,
-                tags: active_tags.to_a.sort)
-          end
-        end
-
-        PostVersion.insert_all!(rows) if rows.any?
-      end
-    end
-  end
-
-  def down
-    drop_table :post_versions
-  end
-
-  private
-
-  def bucket_events events
-    buckets = []
-
-    events.each do |event_at, user_id, kind, tag_name|
-      if buckets.empty? || event_at - buckets.last[:last_at] > 1.second
-        buckets << { first_at: event_at,
-                     last_at: event_at,
-                     user_ids: [user_id],
-                     events: [[kind, tag_name]] }
-      else
-        bucket = buckets.last
-        bucket[:last_at] = event_at
-        bucket[:user_ids] << user_id
-        bucket[:events] << [kind, tag_name]
-      end
-    end
-
-    buckets
-  end
-
-  def apply_bucket! active_tags, bucket
-    bucket[:events].each do |kind, tag_name|
-      if kind == :add
-        active_tags.add(tag_name)
-      else
-        active_tags.delete(tag_name)
-      end
-    end
-  end
-
-  def build_row post:, version_no:, event_type:, created_at:, created_by_user_id:, tags:
-    { post_id: post.id,
-      version_no:,
-      event_type:,
-      title: post.title,
-      url: post.url,
-      thumbnail_base: post.thumbnail_base,
-      tags: tags.join(' '),
-      parent_id: post.parent_id,
-      original_created_from: post.original_created_from,
-      original_created_before: post.original_created_before,
-      created_at:,
-      created_by_user_id: }
-  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_04_09_123700) do
+ActiveRecord::Schema[8.0].define(version: 2025_12_10_123200) 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
@@ -39,60 +39,11 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_09_123700) do
     t.index ["blob_id", "variation_digest"], name: "index_active_storage_variant_records_uniqueness", unique: true
   end
 
-  create_table "deerjikists", primary_key: ["platform", "code"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "platform", limit: 16, null: false
-    t.string "code", null: false
-    t.bigint "tag_id", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["tag_id"], name: "index_deerjikists_on_tag_id"
-  end
-
   create_table "ip_addresses", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.binary "ip_address", limit: 16, null: false
     t.boolean "banned", default: false, null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["ip_address"], name: "index_ip_addresses_on_ip_address", unique: true
-  end
-
-  create_table "material_versions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "material_id", null: false
-    t.integer "version_no", null: false
-    t.string "url"
-    t.bigint "parent_id"
-    t.bigint "tag_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.datetime "discarded_at"
-    t.index ["created_by_user_id"], name: "index_material_versions_on_created_by_user_id"
-    t.index ["discarded_at"], name: "index_material_versions_on_discarded_at"
-    t.index ["material_id", "version_no"], name: "index_material_versions_on_material_id_and_version_no", unique: true
-    t.index ["material_id"], name: "index_material_versions_on_material_id"
-    t.index ["parent_id"], name: "index_material_versions_on_parent_id"
-    t.index ["tag_id"], name: "index_material_versions_on_tag_id"
-    t.index ["updated_by_user_id"], name: "index_material_versions_on_updated_by_user_id"
-    t.index ["url"], name: "index_material_versions_on_url"
-  end
-
-  create_table "materials", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "url"
-    t.bigint "parent_id"
-    t.bigint "tag_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.datetime "discarded_at"
-    t.virtual "active_url", type: :string, as: "if((`discarded_at` is null),`url`,NULL)"
-    t.index ["active_url"], name: "index_materials_on_active_url", unique: true
-    t.index ["created_by_user_id"], name: "index_materials_on_created_by_user_id"
-    t.index ["discarded_at"], name: "index_materials_on_discarded_at"
-    t.index ["parent_id"], name: "index_materials_on_parent_id"
-    t.index ["tag_id"], name: "index_materials_on_tag_id"
-    t.index ["updated_by_user_id"], name: "index_materials_on_updated_by_user_id"
   end
 
   create_table "nico_tag_relations", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -104,11 +55,11 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_09_123700) do
     t.index ["tag_id"], name: "index_nico_tag_relations_on_tag_id"
   end
 
-  create_table "post_similarities", primary_key: ["post_id", "target_post_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+  create_table "post_similarities", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "post_id", null: false
     t.bigint "target_post_id", null: false
     t.float "cos", null: false
-    t.index ["post_id", "cos"], name: "index_post_similarities_on_post_id_and_cos", order: { cos: :desc }
+    t.index ["post_id"], name: "index_post_similarities_on_post_id"
     t.index ["target_post_id"], name: "index_post_similarities_on_target_post_id"
   end
 
@@ -132,31 +83,10 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_09_123700) do
     t.index ["tag_id"], name: "index_post_tags_on_tag_id"
   end
 
-  create_table "post_versions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "post_id", null: false
-    t.integer "version_no", null: false
-    t.string "event_type", null: false
-    t.string "title"
-    t.string "url", limit: 768, null: false
-    t.string "thumbnail_base", limit: 2000
-    t.text "tags", null: false
-    t.bigint "parent_id"
-    t.datetime "original_created_from"
-    t.datetime "original_created_before"
-    t.datetime "created_at", null: false
-    t.bigint "created_by_user_id"
-    t.index ["created_by_user_id"], name: "index_post_versions_on_created_by_user_id"
-    t.index ["parent_id"], name: "index_post_versions_on_parent_id"
-    t.index ["post_id", "version_no"], name: "index_post_versions_on_post_id_and_version_no", unique: true
-    t.index ["post_id"], name: "index_post_versions_on_post_id"
-    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"
-  end
-
   create_table "posts", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "title"
-    t.string "url", limit: 768, null: false
-    t.string "thumbnail_base", limit: 2000
+    t.string "title", null: false
+    t.string "url", limit: 2000, null: false
+    t.string "thumbnail_base", limit: 2000, null: false
     t.bigint "parent_id"
     t.bigint "uploaded_user_id"
     t.datetime "created_at", null: false
@@ -165,7 +95,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_09_123700) do
     t.datetime "updated_at", null: false
     t.index ["parent_id"], name: "index_posts_on_parent_id"
     t.index ["uploaded_user_id"], name: "index_posts_on_uploaded_user_id"
-    t.index ["url"], name: "index_posts_on_url", unique: true
   end
 
   create_table "settings", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -177,6 +106,14 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_09_123700) do
     t.index ["user_id"], name: "index_settings_on_user_id"
   end
 
+  create_table "tag_aliases", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "tag_id", null: false
+    t.string "name", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["tag_id"], name: "index_tag_aliases_on_tag_id"
+  end
+
   create_table "tag_implications", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "tag_id", null: false
     t.bigint "parent_tag_id", null: false
@@ -187,107 +124,38 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_09_123700) do
     t.index ["tag_id"], name: "index_tag_implications_on_tag_id"
   end
 
-  create_table "tag_name_sanitisation_rules", primary_key: "priority", id: :integer, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "source_pattern", null: false
-    t.string "replacement", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.datetime "discarded_at"
-    t.index ["discarded_at"], name: "index_tag_name_sanitisation_rules_on_discarded_at"
-    t.index ["source_pattern"], name: "index_tag_name_sanitisation_rules_on_source_pattern", unique: true
-  end
-
-  create_table "tag_names", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "name", null: false
-    t.bigint "canonical_id"
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.datetime "discarded_at"
-    t.index ["canonical_id"], name: "index_tag_names_on_canonical_id"
-    t.index ["discarded_at"], name: "index_tag_names_on_discarded_at"
-    t.index ["name"], name: "index_tag_names_on_name", unique: true
-  end
-
-  create_table "tag_similarities", primary_key: ["tag_id", "target_tag_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+  create_table "tag_similarities", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "tag_id", null: false
     t.bigint "target_tag_id", null: false
     t.float "cos", null: false
-    t.index ["tag_id", "cos"], name: "index_tag_similarities_on_tag_id_and_cos", order: { cos: :desc }
+    t.index ["tag_id"], name: "index_tag_similarities_on_tag_id"
     t.index ["target_tag_id"], name: "index_tag_similarities_on_target_tag_id"
   end
 
   create_table "tags", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "tag_name_id", null: false
+    t.string "name", null: false
     t.string "category", default: "general", null: false
     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.index ["discarded_at"], name: "index_tags_on_discarded_at"
-    t.index ["tag_name_id"], name: "index_tags_on_tag_name_id", unique: true
   end
 
-  create_table "theatre_comments", primary_key: ["theatre_id", "no"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "theatre_id", null: false
-    t.integer "no", null: false
-    t.bigint "user_id"
-    t.text "content", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.datetime "discarded_at"
-    t.index ["discarded_at"], name: "index_theatre_comments_on_discarded_at"
-    t.index ["theatre_id"], name: "index_theatre_comments_on_theatre_id"
-    t.index ["user_id"], name: "index_theatre_comments_on_user_id"
-  end
-
-  create_table "theatre_watching_users", primary_key: ["theatre_id", "user_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "theatre_id", null: false
-    t.bigint "user_id", null: false
-    t.datetime "expires_at", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["expires_at"], name: "index_theatre_watching_users_on_expires_at"
-    t.index ["theatre_id", "expires_at"], name: "index_theatre_watching_users_on_theatre_id_and_expires_at"
-    t.index ["theatre_id"], name: "index_theatre_watching_users_on_theatre_id"
-    t.index ["user_id"], name: "index_theatre_watching_users_on_user_id"
-  end
-
-  create_table "theatres", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "name"
-    t.datetime "opens_at", null: false
-    t.datetime "closes_at"
-    t.integer "kind", null: false
-    t.bigint "current_post_id"
-    t.datetime "current_post_started_at"
-    t.integer "next_comment_no", default: 1, null: false
-    t.bigint "host_user_id"
-    t.bigint "created_by_user_id", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.datetime "discarded_at"
-    t.index ["closes_at"], name: "index_theatres_on_closes_at"
-    t.index ["created_by_user_id"], name: "index_theatres_on_created_by_user_id"
-    t.index ["current_post_id"], name: "index_theatres_on_current_post_id"
-    t.index ["discarded_at"], name: "index_theatres_on_discarded_at"
-    t.index ["host_user_id"], name: "index_theatres_on_host_user_id"
-    t.index ["kind"], name: "index_theatres_on_kind"
-    t.index ["opens_at"], name: "index_theatres_on_opens_at"
-  end
-
-  create_table "user_ips", primary_key: ["user_id", "ip_address_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+  create_table "user_ips", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "user_id", null: false
     t.bigint "ip_address_id", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.index ["ip_address_id"], name: "index_user_ips_on_ip_address_id"
+    t.index ["user_id"], name: "index_user_ips_on_user_id"
   end
 
-  create_table "user_post_views", primary_key: ["user_id", "post_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+  create_table "user_post_views", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "user_id", null: false
     t.bigint "post_id", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.index ["post_id"], name: "index_user_post_views_on_post_id"
+    t.index ["user_id"], name: "index_user_post_views_on_user_id"
   end
 
   create_table "users", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -299,82 +167,20 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_09_123700) do
     t.datetime "updated_at", null: false
   end
 
-  create_table "wiki_assets", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "wiki_page_id", null: false
-    t.integer "no", null: false
-    t.string "alt_text"
-    t.binary "sha256", limit: 32, null: false
-    t.bigint "created_by_user_id", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["created_by_user_id"], name: "index_wiki_assets_on_created_by_user_id"
-    t.index ["wiki_page_id", "no"], name: "index_wiki_assets_on_wiki_page_id_and_no", unique: true
-    t.index ["wiki_page_id", "sha256"], name: "index_wiki_assets_on_wiki_page_id_and_sha256", unique: true
-  end
-
-  create_table "wiki_lines", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.string "sha256", limit: 64, null: false
-    t.text "body", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["sha256"], name: "index_wiki_lines_on_sha256", unique: true
-  end
-
   create_table "wiki_pages", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "tag_name_id", null: false
+    t.string "title", null: false
+    t.bigint "tag_id"
     t.bigint "created_user_id", null: false
     t.bigint "updated_user_id", null: false
     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.index ["created_user_id"], name: "index_wiki_pages_on_created_user_id"
-    t.index ["discarded_at"], name: "index_wiki_pages_on_discarded_at"
-    t.index ["tag_name_id"], name: "index_wiki_pages_on_tag_name_id", unique: true
+    t.index ["tag_id"], name: "index_wiki_pages_on_tag_id"
     t.index ["updated_user_id"], name: "index_wiki_pages_on_updated_user_id"
   end
 
-  create_table "wiki_revision_lines", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "wiki_revision_id", null: false
-    t.integer "position", null: false
-    t.bigint "wiki_line_id", null: false
-    t.index ["wiki_line_id"], name: "index_wiki_revision_lines_on_wiki_line_id"
-    t.index ["wiki_revision_id", "position"], name: "index_wiki_revision_lines_on_wiki_revision_id_and_position", unique: true
-    t.index ["wiki_revision_id", "wiki_line_id"], name: "index_wiki_revision_lines_on_wiki_revision_id_and_wiki_line_id"
-    t.index ["wiki_revision_id"], name: "index_wiki_revision_lines_on_wiki_revision_id"
-  end
-
-  create_table "wiki_revisions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
-    t.bigint "wiki_page_id", null: false
-    t.bigint "base_revision_id"
-    t.bigint "created_user_id", null: false
-    t.integer "kind", default: 0, null: false
-    t.bigint "redirect_page_id"
-    t.string "message"
-    t.integer "lines_count", default: 0, null: false
-    t.string "tree_sha256", limit: 64
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["base_revision_id"], name: "index_wiki_revisions_on_base_revision_id"
-    t.index ["created_user_id"], name: "index_wiki_revisions_on_created_user_id"
-    t.index ["kind"], name: "index_wiki_revisions_on_kind"
-    t.index ["redirect_page_id"], name: "index_wiki_revisions_on_redirect_page_id"
-    t.index ["tree_sha256"], name: "index_wiki_revisions_on_tree_sha256"
-    t.index ["wiki_page_id", "id"], name: "index_wiki_revisions_on_wiki_page_id_and_id"
-    t.index ["wiki_page_id"], name: "index_wiki_revisions_on_wiki_page_id"
-  end
-
   add_foreign_key "active_storage_attachments", "active_storage_blobs", column: "blob_id"
   add_foreign_key "active_storage_variant_records", "active_storage_blobs", column: "blob_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", "tags"
   add_foreign_key "nico_tag_relations", "tags", column: "nico_tag_id"
   add_foreign_key "post_similarities", "posts"
@@ -383,38 +189,19 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_09_123700) do
   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", "posts", column: "parent_id"
-  add_foreign_key "post_versions", "users", column: "created_by_user_id"
   add_foreign_key "posts", "posts", column: "parent_id"
   add_foreign_key "posts", "users", column: "uploaded_user_id"
   add_foreign_key "settings", "users"
+  add_foreign_key "tag_aliases", "tags"
   add_foreign_key "tag_implications", "tags"
   add_foreign_key "tag_implications", "tags", column: "parent_tag_id"
-  add_foreign_key "tag_names", "tag_names", column: "canonical_id"
   add_foreign_key "tag_similarities", "tags"
   add_foreign_key "tag_similarities", "tags", column: "target_tag_id"
-  add_foreign_key "tags", "tag_names"
-  add_foreign_key "theatre_comments", "theatres"
-  add_foreign_key "theatre_comments", "users"
-  add_foreign_key "theatre_watching_users", "theatres"
-  add_foreign_key "theatre_watching_users", "users"
-  add_foreign_key "theatres", "posts", column: "current_post_id"
-  add_foreign_key "theatres", "users", column: "created_by_user_id"
-  add_foreign_key "theatres", "users", column: "host_user_id"
   add_foreign_key "user_ips", "ip_addresses"
   add_foreign_key "user_ips", "users"
   add_foreign_key "user_post_views", "posts"
   add_foreign_key "user_post_views", "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", "tags"
   add_foreign_key "wiki_pages", "users", column: "created_user_id"
   add_foreign_key "wiki_pages", "users", column: "updated_user_id"
-  add_foreign_key "wiki_revision_lines", "wiki_lines"
-  add_foreign_key "wiki_revision_lines", "wiki_revisions"
-  add_foreign_key "wiki_revisions", "users", column: "created_user_id"
-  add_foreign_key "wiki_revisions", "wiki_pages"
-  add_foreign_key "wiki_revisions", "wiki_pages", column: "redirect_page_id"
-  add_foreign_key "wiki_revisions", "wiki_revisions", column: "base_revision_id"
 end

backend/lib/tasks/calc_post_similarities.rake

@@ -1,6 +1,28 @@
 namespace :post_similarity do
   desc '関聯投稿テーブル作成'
   task calc: :environment do
-    Similarity::Calc.call(Post, :tags)
+    dot = -> a, b { (a.keys & b.keys).sum { |k| a[k] * b[k] } }
+    norm = -> v { Math.sqrt(v.values.sum { |e| e * e }) }
+    cos = -> a, b do
+      na = norm.(a)
+      nb = norm.(b)
+      if na.zero? || nb.zero?
+        0.0
+      else
+        dot.(a, b) / na / nb
+      end
+    end
+
+    posts = Post.includes(:tags).to_a
+    posts.each_with_index do |post, i|
+      existence_of_tags = post.tags.index_with(1)
+      ((i + 1)...posts.size).each do |j|
+        target_post = posts[j]
+        existence_of_target_tags = target_post.tags.index_with(1)
+        PostSimilarity.find_or_initialize_by(post:, target_post:).tap { |ps|
+          ps.cos = cos.(existence_of_tags, existence_of_target_tags)
+        }.save!
+      end
+    end
   end
 end

backend/lib/tasks/calc_tag_similarities.rake

@@ -1,6 +0,0 @@
-namespace :tag_similarity do
-  desc '関聯タグ・テーブル作成'
-  task calc: :environment do
-    Similarity::Calc.call(Tag, :posts)
-  end
-end

backend/lib/tasks/migrate_wiki.rake

@@ -1,74 +0,0 @@
-namespace :wiki do
-  desc 'Wiki 移行'
-  task migrate: :environment do
-    require 'digest'
-    require 'gollum-lib'
-
-    wiki = Gollum::Wiki.new(Rails.root.join('wiki').to_s)
-
-    WikiPage.where.missing(:wiki_revisions).find_each do |wiki_page|
-      page = wiki.page("#{ wiki_page.id }.md")
-      next unless page
-
-      versions = page.versions
-      next if versions.blank?
-
-      base_revision_id = nil
-      versions.reverse_each do |version|
-        pg = wiki.page("#{ wiki_page.id }.md", version.id)
-        raw = pg&.raw_data
-        next unless raw
-
-        lines = raw.force_encoding('UTF-8').split("\n")
-
-        line_shas = lines.map { |l| Digest::SHA256.hexdigest(l) }
-        tree_sha = Digest::SHA256.hexdigest(line_shas.join(','))
-
-        at = version.authored_date
-
-        line_id_by_sha = WikiLine.where(sha256: line_shas).pluck(:sha256, :id).to_h
-
-        missing_rows = []
-        line_shas.each_with_index do |sha, i|
-          next if line_id_by_sha.key?(sha)
-
-          missing_rows << { sha256:     sha,
-                            body:       lines[i],
-                            created_at: at,
-                            updated_at: at }
-        end
-
-        if missing_rows.any?
-          WikiLine.upsert_all(missing_rows)
-          line_id_by_sha = WikiLine.where(sha256: line_shas).pluck(:sha256, :id).to_h
-        end
-        line_ids = line_shas.map { |sha| line_id_by_sha.fetch(sha) }
-
-        rev = nil
-        ActiveRecord::Base.transaction do
-          wiki_page.lock!
-
-          rev = WikiRevision.create!(
-              wiki_page:,
-              base_revision_id:,
-              created_user_id:  (Integer(version.author.name) rescue 2),
-              kind:             :content,
-              redirect_page_id: nil,
-              message:          nil,
-              lines_count:      lines.length,
-              tree_sha256:      tree_sha,
-              created_at:       at,
-              updated_at:       at)
-
-          rows = line_ids.each_with_index.map do |line_id, pos|
-            { wiki_revision_id: rev.id,
-              wiki_line_id:     line_id,
-              position:         pos }
-          end
-          WikiRevisionLine.insert_all!(rows)
-        end
-        base_revision_id = rev.id
-      end
-    end
-  end
-end

backend/lib/tasks/sync_nico.rake

@@ -3,10 +3,9 @@ namespace :nico do
   task sync: :environment do
     require 'json'
     require 'nokogiri'
-    require 'open-uri'
     require 'open3'
+    require 'open-uri'
     require 'set'
-    require 'time'
 
     fetch_thumbnail = -> url do
       html = URI.open(url, read_timeout: 60, 'User-Agent' => 'Mozilla/5.0').read
@@ -15,12 +14,12 @@ namespace :nico do
       doc.at('meta[name="thumbnail"]')&.[]('content').presence
     end
 
-    def sync_post_tags! post, desired_tag_ids, current_tag_ids: nil
-      current_tag_ids ||= PostTag.kept.where(post_id: post.id).pluck(:tag_id).to_set
-      desired_tag_ids = desired_tag_ids.compact.to_set
+    def sync_post_tags! post, desired_tag_ids
+      desired_ids = desired_tag_ids.compact.to_set
+      current_ids = post.tags.pluck(:id).to_set
 
-      to_add = desired_tag_ids - current_tag_ids
-      to_remove = current_tag_ids - desired_tag_ids
+      to_add = desired_ids - current_ids
+      to_remove = current_ids - desired_ids
 
       Tag.where(id: to_add.to_a).find_each do |tag|
         begin
@@ -42,54 +41,18 @@ namespace :nico do
         { 'MYSQL_USER' => mysql_user, 'MYSQL_PASS' => mysql_pass },
         'python3', "#{ nizika_nico_path }/get_videos.py")
 
-    unless status.success?
-      warn stderr
-      abort
-    end
+    abort unless status.success?
 
     data = JSON.parse(stdout)
     data.each do |datum|
-      code = datum['code']
-      post =
-          Post
-          .where('url REGEXP ?', "nicovideo\\.jp/watch/#{ Regexp.escape(code) }([^0-9]|$)")
-          .first
-
+      post = Post.where('url LIKE ?', '%nicovideo.jp%').find { |post|
+        post.url =~ %r{#{ Regexp.escape(datum['code']) }(?!\d)}
+      }
+      unless post
         title = datum['title']
-      original_created_at = datum['uploaded_at'] &&
-          Time.strptime(datum['uploaded_at'], '%Y-%m-%d %H:%M:%S')
-      original_created_from = original_created_at&.change(sec: 0)
-      original_created_before = original_created_from&.+(1.minute)
-
-      post_created = false
-      post_changed = false
-
-      if post
-        attrs = { title:, original_created_from:, original_created_before: }
-
-        unless post.thumbnail.attached?
-          thumbnail_base = fetch_thumbnail.(post.url) rescue nil
-          if thumbnail_base.present?
-            post.thumbnail.attach(
-                io:           URI.open(thumbnail_base),
-                filename:     File.basename(URI.parse(thumbnail_base).path),
-                content_type: 'image/jpeg')
-            attrs[:thumbnail_base] = thumbnail_base
-          end
-        end
-
-        post.assign_attributes(attrs)
-        post_changed = post.changed?
-        if post_changed
-          post.save!
-          post.resized_thumbnail! if post.thumbnail.attached?
-        end
-      else
-        post_created = true
-        url = "https://www.nicovideo.jp/watch/#{ code }"
-        thumbnail_base = fetch_thumbnail.(url) rescue nil
-        post = Post.new(title:, url:, thumbnail_base:, uploaded_user: nil,
-                        original_created_from:, original_created_before:)
+        url = "https://www.nicovideo.jp/watch/#{ datum['code'] }"
+        thumbnail_base = fetch_thumbnail.(url) || '' rescue ''
+        post = Post.new(title:, url:, thumbnail_base:, uploaded_user: nil)
         if thumbnail_base.present?
           post.thumbnail.attach(
               io:           URI.open(thumbnail_base),
@@ -98,59 +61,40 @@ namespace :nico do
         end
         post.save!
         post.resized_thumbnail!
-        sync_post_tags!(post, [Tag.tagme.id, Tag.bot.id, Tag.niconico.id, Tag.video.id])
+        sync_post_tags!(post, [Tag.tagme.id])
       end
 
-      tags = post.tags
-      # 既存のタグ Id. 集合
-      kept_tag_ids = tags.pluck(:id).to_set
-      # うち内部タグ Id. 集合
-      kept_non_nico_tag_ids = tags.not_nico.pluck(:id).to_set
-
-      # 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_non_nico_tag_ids = []
+      kept_tags = post.tags.reload
+      kept_non_nico_ids = kept_tags.where.not(category: 'nico').pluck(:id).to_set
 
+      desired_nico_ids = []
+      desired_non_nico_ids = []
       datum['tags'].each do |raw|
-        name = TagNameSanitisationRule.sanitise("nico:#{ raw }")
-        tag = Tag.find_or_create_by_tag_name!(name, category: :nico)
-        desired_nico_tag_based_ids << tag.id
+        name = "nico:#{ raw }"
+        tag = Tag.find_or_initialize_by(name:) do |t|
+          t.category = 'nico'
+        end
+        tag.save! if tag.new_record?
+        desired_nico_ids << tag.id
+        unless tag.in?(kept_tags)
+          desired_non_nico_ids.concat(tag.linked_tags.pluck(:id))
+          desired_nico_ids.concat(tag.linked_tags.pluck(:id))
+        end
+      end
+      desired_nico_ids.uniq!
 
-        # 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
-        unless tag.id.in?(kept_tag_ids)
-          linked_ids = tag.linked_tags.pluck(:id)
-          desired_non_nico_tag_ids.concat(linked_ids)
-          desired_nico_tag_based_ids.concat(linked_ids)
+      desired_all_ids = kept_non_nico_ids.to_a + desired_nico_ids
+      desired_non_nico_ids.concat(kept_non_nico_ids.to_a)
+      desired_non_nico_ids.uniq!
+      if kept_non_nico_ids.to_set != desired_non_nico_ids.to_set
+        desired_all_ids << Tag.bot.id
       end
+      unless Tag.where(id: desired_all_ids).where(category: 'deerjikist').exists?
+        desired_all_ids << Tag.no_deerjikist.id
       end
+      desired_all_ids.uniq!
 
-      deerjikist = Deerjikist.find_by(platform: :nico, code: datum['user'])
-      if deerjikist
-        desired_non_nico_tag_ids << deerjikist.tag_id
-        desired_nico_tag_based_ids << deerjikist.tag_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_nico_tag_based_ids.uniq!
-
-      desired_all_tag_ids = kept_non_nico_tag_ids.to_a + desired_nico_tag_based_ids
-      desired_non_nico_tag_ids.concat(kept_non_nico_tag_ids.to_a)
-      desired_non_nico_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!
-
-      sync_post_tags!(post, desired_all_tag_ids, current_tag_ids: kept_tag_ids)
-
-      if post_created
-        PostVersionRecorder.record!(post:, event_type: :create, created_by_user: nil)
-      elsif post_changed || kept_tag_ids != desired_all_tag_ids.to_set
-        PostVersionRecorder.record!(post:, event_type: :update, created_by_user: nil)
-      end
+      sync_post_tags!(post, desired_all_ids)
     end
   end
 end

backend/spec/factories/tag_names.rb

@@ -1,5 +0,0 @@
-FactoryBot.define do
-  factory :tag_name do
-    name { "tag-#{SecureRandom.hex(4)}" }
-  end
-end

backend/spec/factories/tags.rb

@@ -1,22 +0,0 @@
-FactoryBot.define do
-  factory :tag do
-    transient do
-      name { nil }
-    end
-
-    category { :general }
-    post_count { 0 }
-    association :tag_name
-
-    after(:build) do |tag, evaluator|
-      tag.name = evaluator.name if evaluator.name.present?
-    end
-
-    trait :nico do
-      category { :nico }
-      transient do
-        name { "nico:#{ SecureRandom.hex(4) }" }
-      end
-    end
-  end
-end

backend/spec/factories/theatre_comments.rb

@@ -1,8 +0,0 @@
-FactoryBot.define do
-  factory :theatre_comment do
-    association :theatre
-    association :user
-    sequence (:no) { |n| n }
-    content { 'test comment' }
-  end
-end

backend/spec/factories/theatres.rb

@@ -1,11 +0,0 @@
-FactoryBot.define do
-  factory :theatre do
-    name { 'Test Theatre' }
-    kind { 1 }
-    opens_at { Time.current }
-    closes_at { 1.day.from_now }
-    next_comment_no { 1 }
-
-    association :created_by_user, factory: :user
-  end
-end

backend/spec/factories/users.rb

@@ -1,15 +0,0 @@
-FactoryBot.define do
-  factory :user do
-    name { "test-user" }
-    inheritance_code { SecureRandom.uuid }
-    role { "guest" }
-
-    trait :member do
-      role { "member" }
-    end
-
-    trait :admin do
-      role { 'admin' }
-    end
-  end
-end

backend/spec/factories/wiki_pages.rb

@@ -1,7 +0,0 @@
-FactoryBot.define do
-  factory :wiki_page do
-    title { "TestPage" }
-    association :created_user, factory: :user
-    association :updated_user, factory: :user
-  end
-end

backend/spec/models/post_version_spec.rb

@@ -1,41 +0,0 @@
-require 'rails_helper'
-
-RSpec.describe PostVersion, type: :model do
-  let!(:tag_name) { TagName.create!(name: 'post_version_spec_tag') }
-  let!(:tag) { Tag.create!(tag_name: tag_name, category: :general) }
-
-  let!(:post_record) do
-    Post.create!(title: 'spec post', url: 'https://example.com/post-version-spec').tap do |post|
-      PostTag.create!(post: post, tag: tag)
-    end
-  end
-
-  let!(:post_version) do
-    PostVersion.create!(
-      post: post_record,
-      version_no: 1,
-      event_type: 'create',
-      title: post_record.title,
-      url: post_record.url,
-      thumbnail_base: post_record.thumbnail_base,
-      tags: post_record.snapshot_tag_names.join(' '),
-      parent: post_record.parent,
-      original_created_from: post_record.original_created_from,
-      original_created_before: post_record.original_created_before,
-      created_at: Time.current,
-      created_by_user: nil
-    )
-  end
-
-  it 'is read only after create' do
-    expect do
-      post_version.update!(title: 'changed')
-    end.to raise_error(ActiveRecord::ReadOnlyRecord)
-  end
-
-  it 'cannot be destroyed' do
-    expect do
-      post_version.destroy!
-    end.to raise_error(ActiveRecord::ReadOnlyRecord)
-  end
-end