#327

#63

#63

#63

#63

Co-authored-by: miteruzo <miteruzo@naver.com>
Reviewed-on: #341

backend/app/controllers/application_controller.rb

@@ -1,14 +1,16 @@
 class ApplicationController < ActionController::API
+  before_action :reject_banned_ip_address!
   before_action :authenticate_user
+  before_action :reject_banned_user!
 
-  def current_user
+  def current_user = @current_user
-    @current_user
-  end
 
   private
 
   def authenticate_user
     code = request.headers['X-Transfer-Code'] || request.headers['HTTP_X_TRANSFER_CODE']
+    return if code.blank?
+
     @current_user = User.find_by(inheritance_code: code)
   end
 
@@ -22,4 +24,17 @@ class ApplicationController < ActionController::API
       s.in?(['', '1', 'true', 'on', 'yes'])
     end
   end
+
+  def reject_banned_ip_address!
+    ip_address = IpAddress.find_by(ip_address: IPAddr.new(request.remote_ip).hton)
+    return unless ip_address&.banned?
+
+    head :forbidden
+  end
+
+  def reject_banned_user!
+    return unless current_user&.banned?
+
+    head :forbidden
+  end
 end

backend/app/controllers/nico_tags_controller.rb

@@ -33,7 +33,7 @@ class NicoTagsController < ApplicationController
     return head :bad_request unless tag.nico?
 
     linked_tag_names = params[:tags].to_s.split
-    linked_tags = Tag.normalise_tags(linked_tag_names, with_tagme: false,
+    linked_tags = Tag.normalise_tags!(linked_tag_names, with_tagme: false,
                                                         with_no_deerjikist: false)
     return head :bad_request if linked_tags.any? { |t| t.nico? }
 

backend/app/controllers/posts_controller.rb

@@ -109,7 +109,7 @@ class PostsController < ApplicationController
 
     render json: PostRepr.base(post, current_user)
                          .merge(tags: build_tag_tree_for(post.tags),
-                                related: post.related(limit: 20))
+                                related: PostRepr.many(post.related(limit: 20)))
   end
 
   def create
@@ -123,28 +123,36 @@ class PostsController < ApplicationController
     tag_names = params[:tags].to_s.split
     original_created_from = params[:original_created_from]
     original_created_before = params[:original_created_before]
+    parent_post_ids = parse_parent_post_ids
 
     post = Post.new(title:, url:, thumbnail_base: nil, uploaded_user: current_user,
                     original_created_from:, original_created_before:)
-    post.thumbnail.attach(thumbnail)
+    post.thumbnail.attach(thumbnail) if thumbnail.present?
 
     ApplicationRecord.transaction do
       post.save!
-      tags = Tag.normalise_tags(tag_names)
+
+      tags = Tag.normalise_tags!(tag_names)
       TagVersioning.record_tag_snapshots!(tags, created_by_user: current_user)
 
       tags = Tag.expand_parent_tags(tags)
       sync_post_tags!(post, tags)
+
+      sync_parent_posts!(post, parent_post_ids)
+
       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: { errors: post.errors.full_messages }, status: :unprocessable_entity
   rescue Tag::NicoTagNormalisationError
     head :bad_request
+  rescue ArgumentError => e
+    render json: { errors: [e.message] }, status: :unprocessable_entity
+  rescue ActiveRecord::RecordInvalid => e
+    render json: { errors: e.record.errors.full_messages }, status: :unprocessable_entity
   end
 
   def viewed
@@ -169,6 +177,7 @@ class PostsController < ApplicationController
     tag_names = params[:tags].to_s.split
     original_created_from = params[:original_created_from]
     original_created_before = params[:original_created_before]
+    parent_post_ids = parse_parent_post_ids
 
     post = Post.find(params[:id].to_i)
 
@@ -177,12 +186,15 @@ class PostsController < ApplicationController
 
       post.update!(title:, original_created_from:, original_created_before:)
 
-      normalised_tags = Tag.normalise_tags(tag_names, with_tagme: false)
+      normalised_tags = Tag.normalise_tags!(tag_names, with_tagme: false)
       TagVersioning.record_tag_snapshots!(normalised_tags, created_by_user: current_user)
 
       tags = post.tags.nico.to_a + normalised_tags
       tags = Tag.expand_parent_tags(tags)
       sync_post_tags!(post, tags)
+
+      sync_parent_posts!(post, parent_post_ids)
+
       PostVersionRecorder.record!(post:, event_type: :update, created_by_user: current_user)
     end
 
@@ -190,10 +202,12 @@ class PostsController < ApplicationController
     json = post.as_json
     json['tags'] = build_tag_tree_for(post.tags)
     render json:, status: :ok
-  rescue ActiveRecord::RecordInvalid
-    render json: post.errors, status: :unprocessable_entity
   rescue Tag::NicoTagNormalisationError
     head :bad_request
+  rescue ArgumentError => e
+    render json: { errors: [e.message] }, status: :unprocessable_entity
+  rescue ActiveRecord::RecordInvalid => e
+    render json: { errors: e.record.errors.full_messages }, status: :unprocessable_entity
   end
 
   def changes
@@ -353,4 +367,41 @@ class PostsController < ApplicationController
 
     root_ids.filter_map { |id| build_node.call(id, []) }
   end
+
+  def parse_parent_post_ids
+    raise ArgumentError, 'parent_post_ids は必須です．' unless params.key?(:parent_post_ids)
+
+    params[:parent_post_ids].to_s.split.map { |token|
+      id = Integer(token, exception: false)
+      raise ArgumentError, "親投稿 Id. が不正です: #{ token }" if id.nil? || id <= 0
+
+      id
+    }.uniq
+  end
+
+  def sync_parent_posts! post, parent_post_ids
+    if parent_post_ids.include?(post.id)
+      post.errors.add(:base, '自分自身を親投稿にはできません．')
+      raise ActiveRecord::RecordInvalid, post
+    end
+
+    existing_ids = Post.where(id: parent_post_ids).pluck(:id)
+    missing_ids = parent_post_ids - existing_ids
+
+    if missing_ids.present?
+      post.errors.add(:base, "存在しない親投稿 ID があります: #{ missing_ids.join(' ') }")
+      raise ActiveRecord::RecordInvalid, post
+    end
+
+    current_ids = post.parent_posts.pluck(:id)
+
+    ids_to_add = parent_post_ids - current_ids
+    ids_to_remove = current_ids - parent_post_ids
+
+    PostImplication.where(post_id: post.id, parent_post_id: ids_to_remove).delete_all
+
+    ids_to_add.each do |parent_post_id|
+      PostImplication.create_or_find_by!(post_id: post.id, parent_post_id:)
+    end
+  end
 end

backend/app/controllers/tags_controller.rb

@@ -1,3 +1,7 @@
+require 'net/http'
+require 'uri'
+
+
 class TagsController < ApplicationController
   def index
     post_id = params[:post]
@@ -182,7 +186,8 @@ class TagsController < ApplicationController
              .find_by(id: params[:id])
     return head :not_found unless tag
 
-    render json: DeerjikistRepr.many(tag.deerjikists)
+    render json: { tag: TagRepr.base(tag),
+                   deerjikists: DeerjikistRepr.many(tag.deerjikists) }
   end
 
   def deerjikists_by_name
@@ -194,7 +199,31 @@ class TagsController < ApplicationController
              .find_by(tag_names: { name: })
     return head :not_found unless tag
 
-    render json: DeerjikistRepr.many(tag.deerjikists)
+    render json: { tag: TagRepr.base(tag),
+                   deerjikists: DeerjikistRepr.many(tag.deerjikists) }
+  end
+
+  def update_deerjikists
+    return head :unauthorized unless current_user
+    return head :forbidden unless current_user.gte_member?
+
+    tag = Tag.joins(:tag_name)
+             .includes(:tag_name, tag_name: :wiki_page)
+             .find_by(id: params[:id])
+    return head :not_found unless tag
+
+    ApplicationRecord.transaction do
+      tag.deerjikists = []
+      params[:_json].each do
+        platform = _1[:platform]
+        code = normalise_deerjikist_code(platform, _1[:code])
+        deerjikist = Deerjikist.find_or_initialize_by(platform:, code:)
+        deerjikist.tag = tag
+        deerjikist.save!
+      end
+    end
+
+    render json: DeerjikistRepr.many(tag.reload.deerjikists)
   end
 
   def materials_by_name
@@ -238,18 +267,26 @@ class TagsController < ApplicationController
       TagVersioning.ensure_snapshot!(tag, created_by_user: current_user)
 
       old_name = tag.name
+      name_changed = name != old_name
+      wiki_page = tag.tag_name.wiki_page if name_changed
 
       tag.update!(category:)
       tag.tag_name.update!(name:)
 
-      alias_names << old_name if name != old_name
+      alias_names << old_name if name_changed
       alias_names.delete(name)
 
       update_aliases!(tag, alias_names)
       update_parent_tags!(tag, parent_names)
 
       tag.reload
-      record_tag_version!(tag, event_type: :update, created_by_user: current_user)
+
+      record_tag_version!(
+          tag,
+          event_type: :update,
+          created_by_user: current_user,
+          name_changed:,
+          wiki_page:)
     end
 
     render json: TagRepr.base(tag.reload)
@@ -272,10 +309,21 @@ class TagsController < ApplicationController
     ApplicationRecord.transaction do
       TagVersioning.ensure_snapshot!(tag, created_by_user: current_user)
 
+      old_name = tag.name
+      name_changed = name.present? && name != old_name
+      wiki_page = tag.tag_name.wiki_page if name_changed
+
       tag.tag_name.update!(name:) if name.present?
       tag.update!(category:) if category.present?
 
-      record_tag_version!(tag, event_type: :update, created_by_user: current_user)
+      tag.reload
+
+      record_tag_version!(
+          tag,
+          event_type: :update,
+          created_by_user: current_user,
+          name_changed:,
+          wiki_page:)
     end
 
     render json: TagRepr.base(tag.reload)
@@ -297,17 +345,47 @@ class TagsController < ApplicationController
         material: material.as_json&.merge(file:, content_type:))
   end
 
-  def record_tag_version! tag, event_type:, created_by_user:
+  def record_tag_version! tag, event_type:, created_by_user:, name_changed: false, wiki_page: nil
     if tag.nico?
       NicoTagVersionRecorder.record!(tag:, event_type:, created_by_user:)
-    else
+      return
-      TagVersionRecorder.record!(tag:, event_type:, created_by_user:)
     end
+
+    TagVersionRecorder.record!(tag:, event_type:, created_by_user:)
+
+    return unless name_changed
+
+    wiki_page ||= tag.tag_name.wiki_page
+    return unless wiki_page&.wiki_versions&.exists?
+
+    WikiVersionRecorder.record!(
+        page: wiki_page,
+        event_type: :update,
+        created_by_user:)
   end
 
   def update_aliases! tag, alias_names
+    alias_names = alias_names.uniq
+
+    affected_tags = [tag]
+
     current_aliases = tag.tag_name.aliases.to_a
 
+    current_aliases.each do |alias_tag_name|
+      next if alias_names.include?(alias_tag_name.name)
+
+      affected_tags << alias_tag_name.canonical&.tag
+    end
+
+    alias_names.each do |alias_name|
+      alias_tag_name = TagName.find_undiscard_or_create_by!(name: alias_name)
+      affected_tags << alias_tag_name.canonical&.tag
+    end
+
+    affected_tags.compact.uniq.each do |affected_tag|
+      TagVersioning.ensure_snapshot!(affected_tag, created_by_user: current_user)
+    end
+
     current_aliases.each do |alias_tag_name|
       next if alias_names.include?(alias_tag_name.name)
 
@@ -318,10 +396,14 @@ class TagsController < ApplicationController
       alias_tag_name = TagName.find_undiscard_or_create_by!(name: alias_name)
       alias_tag_name.update!(canonical: tag.tag_name)
     end
+
+    affected_tags.compact.uniq.each do |affected_tag|
+      record_tag_version!(affected_tag, event_type: :update, created_by_user: current_user)
+    end
   end
 
   def update_parent_tags! tag, parent_names
-    parent_tags = Tag.normalise_tags(parent_names, with_tagme: false,
+    parent_tags = Tag.normalise_tags!(parent_names, with_tagme: false,
                                                     with_no_deerjikist: false,
                                                     deny_nico: true)
 
@@ -338,4 +420,21 @@ class TagsController < ApplicationController
       TagImplication.create!(tag:, parent_tag:)
     end
   end
+
+  def normalise_deerjikist_code platform, code
+    return code if platform != 'youtube' || code[0] != '@'
+
+    url = "https://www.youtube.com/#{ code }"
+
+    html = Net::HTTP.get(URI(url))
+
+    canonical = html[
+        /<link rel="canonical" href="https:\/\/www\.youtube\.com\/channel\/(UC[a-zA-Z0-9_-]{22})"/,
+        1]
+    return canonical if canonical
+
+    html[/"channelId":"(UC[a-zA-Z0-9_-]{22})"/, 1] || html[/\bUC[a-zA-Z0-9_-]{22}\b/]
+  rescue
+    nil
+  end
 end

backend/app/controllers/users_controller.rb

@@ -1,18 +1,22 @@
 class UsersController < ApplicationController
   def create
-    user = User.create!(inheritance_code: SecureRandom.uuid, role: 'guest')
+    user = nil
+    User.transaction do
+      user = User.create!(inheritance_code: SecureRandom.uuid, role: :guest)
+      attach_ip_address!(user)
+    end
+
     render json: { code: user.inheritance_code,
-                   user: user.slice(:id, :name, :inheritance_code, :role) }
+                   user: user.slice(:id, :name, :inheritance_code, :role) },
+           status: :created
   end
 
   def verify
-    ip_bin = IPAddr.new(request.remote_ip).hton
-    ip_address = IpAddress.find_or_create_by!(ip_address: ip_bin)
-
     user = User.find_by(inheritance_code: params[:code])
     return render json: { valid: false } unless user
+    return head :forbidden if user.banned?
 
-    UserIp.find_or_create_by!(user:, ip_address:)
+    attach_ip_address!(user)
 
     render json: { valid: true, user: user.slice(:id, :name, :inheritance_code, :role) }
   end
@@ -41,9 +45,18 @@ class UsersController < ApplicationController
     return head :bad_request if name.blank?
 
     if user.update(name:)
-      render json: user.slice(:id, :name, :inheritance_code, :role), status: :created
+      render json: user.slice(:id, :name, :inheritance_code, :role), status: :ok
     else
       render json: user.errors, status: :unprocessable_entity
     end
   end
+
+  private
+
+  def attach_ip_address! user
+    ip_bin = IPAddr.new(request.remote_ip).hton
+    ip_address = IpAddress.create_or_find_by!(ip_address: ip_bin)
+
+    UserIp.create_or_find_by!(user:, ip_address:)
+  end
 end

backend/app/controllers/wiki_pages_controller.rb

@@ -85,22 +85,24 @@ class WikiPagesController < ApplicationController
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    name = params[:title]&.strip
+    title = params[:title].to_s.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:)
+
+    return head :unprocessable_entity if title.blank? || body.blank?
+
+    tag_name = TagName.find_undiscard_or_create_by!(name: title)
+
+    page =
+        Wiki::Commit.create_content!(
+            tag_name:,
+            body:,
+            created_by_user: current_user,
+            message:)
 
     render json: WikiPageRepr.base(page), status: :created
-    else
+  rescue ActiveRecord::RecordInvalid, ActiveRecord::RecordNotUnique
-      render json: { errors: page.errors.full_messages },
+    head :unprocessable_entity
-             status: :unprocessable_entity
-    end
   end
 
   def update
@@ -113,12 +115,21 @@ class WikiPagesController < ApplicationController
     return head :unprocessable_entity if title.blank? || body.blank?
 
     page = WikiPage.find(params[:id])
-    base_revision_id = page.current_revision.id
+    base_revision_id = params[:base_revision_id].presence
 
-    if params[:title].present? && params[:title].strip != page.title
+    ApplicationRecord.transaction do
-      return head :unprocessable_entity
+      page.lock!
+
+      old_title = page.title
+
+      tag = Tag.find_by(tag_name_id: page.tag_name_id)
+
+      if tag && title != old_title
+        TagVersioning.ensure_snapshot!(tag, created_by_user: current_user)
       end
 
+      page.tag_name.update!(name: title) if title != old_title
+
       message = params[:message].presence
       Wiki::Commit.content!(page:,
                             body:,
@@ -126,6 +137,12 @@ class WikiPagesController < ApplicationController
                             message:,
                             base_revision_id:)
 
+      if tag && title != old_title
+        tag.reload
+        TagVersionRecorder.record!(tag:, event_type: :update, created_by_user: current_user)
+      end
+    end
+
     head :ok
   end
 

backend/app/models/ip_address.rb

@@ -1,6 +1,10 @@
 class IpAddress < ApplicationRecord
   validates :ip_address, presence: true, length: { maximum: 16 }
-  validates :banned, inclusion: { in: [true, false] }
 
-  has_many :users
+  has_many :user_ips, dependent: :destroy
+  has_many :users, through: :user_ips
+
+  def banned? = banned_at.present?
+  def ban! = banned? || update!(banned_at: Time.current)
+  def unban! = update!(banned_at: nil)
 end

backend/app/models/post.rb

@@ -1,7 +1,6 @@
 class Post < ApplicationRecord
   require 'mini_magick'
 
-  belongs_to :parent, class_name: 'Post', optional: true, foreign_key: 'parent_id'
   belongs_to :uploaded_user, class_name: 'User', optional: true
 
   has_many :post_tags, dependent: :destroy, inverse_of: :post
@@ -13,6 +12,20 @@ class Post < ApplicationRecord
   has_many :post_similarities, dependent: :delete_all
   has_many :post_versions
 
+  has_many :parent_post_implications,
+           class_name: 'PostImplication',
+           foreign_key: :post_id,
+           dependent: :destroy,
+           inverse_of: :post
+  has_many :parents, through: :parent_post_implications, source: :parent_post
+
+  has_many :child_post_implications,
+           class_name: 'PostImplication',
+           foreign_key: :parent_post_id,
+           dependent: :destroy,
+           inverse_of: :parent_post
+  has_many :children, through: :child_post_implications, source: :post
+
   has_one_attached :thumbnail
 
   before_validation :normalise_url
@@ -22,17 +35,29 @@ class Post < ApplicationRecord
   validate :validate_original_created_range
   validate :url_must_be_http_url
 
+  def parent_posts = parents
+
+  def child_posts = children
+
+  def sibling_posts
+    parent_post_ids = parent_posts.order(:id).pluck(:id)
+
+    parent_post_ids.to_h { [_1, PostImplication.where(parent_post: _1).map(&:post)] }
+  end
+
   def as_json options = { }
-    super(options).merge({ thumbnail: thumbnail.attached? ?
+    super(options).merge(thumbnail: thumbnail.attached? ?
                                     Rails.application.routes.url_helpers.rails_blob_url(
                                         thumbnail, only_path: false) :
-                                      nil })
+                                    nil)
   rescue
     super(options).merge(thumbnail: nil)
   end
 
   def snapshot_tag_names = tags.joins(:tag_name).order('tag_names.name').pluck('tag_names.name')
 
+  def snapshot_parent_post_ids = parents.order(:id).pluck(:id)
+
   def related limit: nil
     ids = post_similarities.order(cos: :desc)
     ids = ids.limit(limit) if limit

backend/app/models/post_implication.rb

@@ -0,0 +1,19 @@
+class PostImplication < ApplicationRecord
+  self.primary_key = :post_id, :parent_post_id
+
+  belongs_to :post, inverse_of: :parent_post_implications
+  belongs_to :parent_post, class_name: 'Post', inverse_of: :child_post_implications
+
+  validates :post_id, presence: true, uniqueness: { scope: :parent_post_id }
+  validates :parent_post_id, presence: true
+
+  validate :parent_post_mustnt_be_itself
+
+  private
+
+  def parent_post_mustnt_be_itself
+    if parent_post_id == post_id
+      errors.add :parent_post_id, '親投稿に同じ投稿を設定することはできません．'
+    end
+  end
+end

backend/app/models/tag.rb

@@ -79,13 +79,16 @@ class Tag < ApplicationRecord
 
   def material_id = materials.first&.id
 
+  def has_deerjikists = deerjikists.present?
+
   def self.tagme = find_or_create_by_tag_name!('タグ希望', category: :meta)
   def self.bot = find_or_create_by_tag_name!('bot操作', category: :meta)
   def self.no_deerjikist = find_or_create_by_tag_name!('ニジラー情報不詳', category: :meta)
   def self.video = find_or_create_by_tag_name!('動画', category: :meta)
   def self.niconico = find_or_create_by_tag_name!('ニコニコ', category: :meta)
+  def self.youtube = find_or_create_by_tag_name!('YouTube', category: :meta)
 
-  def self.normalise_tags tag_names, with_tagme: true,
+  def self.normalise_tags! tag_names, with_tagme: true,
                                       with_no_deerjikist: true,
                                       deny_nico: true
     if deny_nico && tag_names.any? { |n| n.downcase.start_with?('nico:') }

backend/app/models/user.rb

@@ -4,7 +4,6 @@ class User < ApplicationRecord
   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
@@ -19,5 +18,10 @@ class User < ApplicationRecord
            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 banned? = banned_at.present?
+  def ban! = banned? || update!(banned_at: Time.current)
+  def unban! = update!(banned_at: nil)
 end

backend/app/models/wiki_page.rb

@@ -13,8 +13,11 @@ class WikiPage < ApplicationRecord
            foreign_key: :redirect_page_id,
            dependent: :nullify
 
+  has_many :wiki_versions
+
   belongs_to :tag_name
   validates :tag_name, presence: true
+  validates :body, presence: true
 
   def title = tag_name.name
 
@@ -24,11 +27,6 @@ class WikiPage < ApplicationRecord
 
   def current_revision = wiki_revisions.order(id: :desc).first
 
-  def body
-    rev = current_revision
-    rev.body if rev&.content?
-  end
-
   def resolve_redirect limit: 10
     page = self
     visited = Set.new

backend/app/models/wiki_version.rb

@@ -0,0 +1,8 @@
+class WikiVersion < ApplicationRecord
+  include VersionRecord
+
+  belongs_to :wiki_page
+
+  validates :title, presence: true
+  validates :body, presence: true
+end

backend/app/representations/post_repr.rb

@@ -2,7 +2,8 @@
 
 
 module PostRepr
-  BASE = { include: { tags: TagRepr::BASE, uploaded_user: UserRepr::BASE } }.freeze
+  BASE = { include: { tags: TagRepr::BASE, uploaded_user: UserRepr::BASE },
+           methods: [:parent_posts, :child_posts, :sibling_posts] }.freeze
 
   module_function
 

backend/app/representations/tag_repr.rb

@@ -3,7 +3,7 @@
 
 module TagRepr
   BASE = { only: [:id, :category, :post_count, :created_at, :updated_at],
-           methods: [:name, :has_wiki, :material_id] }.freeze
+           methods: [:name, :has_wiki, :material_id, :has_deerjikists] }.freeze
 
   module_function
 

backend/app/services/post_version_recorder.rb

@@ -24,7 +24,7 @@ class PostVersionRecorder < VersionRecorder
       url: @record.url,
       thumbnail_base: @record.thumbnail_base,
       tags: @record.snapshot_tag_names.join(' '),
-      parent_id: @record.parent_id,
+      parent_post_ids: @record.snapshot_parent_post_ids.join(' '),
       original_created_from: @record.original_created_from,
       original_created_before: @record.original_created_before }
   end

backend/app/services/wiki/commit.rb

@@ -7,6 +7,31 @@ module Wiki
       ;
     end
 
+    def self.create_content! tag_name:, body:, created_by_user:, message: nil
+      normalised = normalise_body(body)
+
+      page = WikiPage.new(tag_name:,
+                          body: normalised,
+                          created_user: created_by_user,
+                          updated_user: created_by_user)
+
+      if normalised.blank?
+        page.errors.add(:body, :blank)
+        raise ActiveRecord::RecordInvalid, page
+      end
+
+      ActiveRecord::Base.transaction do
+        page.save!
+
+        new(page:, created_user: created_by_user).content!(
+            body: normalised,
+            message:,
+            base_revision_id: nil)
+
+        page
+      end
+    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
@@ -21,7 +46,12 @@ module Wiki
     end
 
     def content! body:, message:, base_revision_id:
-      normalised = normalise_body(body)
+      normalised = self.class.normalise_body(body)
+      if normalised.blank?
+        @page.errors.add(:body, :blank)
+        raise ActiveRecord::RecordInvalid, @page
+      end
+
       lines = split_lines(normalised)
 
       line_shas = lines.map { |line| Digest::SHA256.hexdigest(line) }
@@ -37,10 +67,19 @@ module Wiki
           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 }）．"
+                "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
 
+        @page.update!(body: normalised)
+
+        WikiVersionRecorder.record!(
+            page: @page,
+            event_type: @page.wiki_versions.exists? ? :update : :create,
+            reason: message,
+            created_by_user: @created_user)
+
         rev = WikiRevision.create!(
             wiki_page:        @page,
             base_revision_id:,
@@ -54,65 +93,45 @@ module Wiki
         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)
+        WikiRevisionLine.insert_all!(rows) if rows.any?
 
         rev
       end
     end
 
-    def redirect! redirect_page:, message:, base_revision_id:
+    def redirect!(redirect_page:, message:, base_revision_id:) = raise '廃止しました．'
-      ActiveRecord::Base.transaction do
-        @page.lock!
 
-        if base_revision_id.present?
+    def self.normalise_body body
-          current_id = @page.wiki_revisions.maximum(:id)
+      s = body.to_s
-          if current_id && current_id != base_revision_id.to_i
+      s.gsub!(/\r\n?/, "\n")
-            raise Conflict,
+      s.encode('UTF-8', invalid: :replace, undef: :replace, replace: '🖕')
-                "競合が発生してゐます（現在の Id.：#{ current_id }，ベース Id.：#{ base_revision_id }）．"
+      s.gsub(/\n+$/, '')
-          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
+    def split_lines(body) = body.split("\n")
-      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 = []
+      missing_by_sha = { }
+
       line_shas.each_with_index do |sha, i|
         next if id_by_sha.key?(sha)
+        next if missing_by_sha.key?(sha)
 
-        missing_rows << { sha256:     sha,
+        missing_by_sha[sha] = {
+            sha256:     sha,
             body:       lines[i],
             created_at: now,
             updated_at: now }
       end
 
-      if missing_rows.any?
+      if missing_by_sha.any?
-        WikiLine.upsert_all(missing_rows)
+        WikiLine.upsert_all(missing_by_sha.values)
         id_by_sha = WikiLine.where(sha256: line_shas).pluck(:sha256, :id).to_h
       end
 

backend/app/services/wiki_version_recorder.rb

@@ -0,0 +1,21 @@
+class WikiVersionRecorder < VersionRecorder
+  def self.record! page:, event_type:, reason: nil, created_by_user:
+    new(page:, event_type:, reason:, created_by_user:).record!
+  end
+
+  def initialize page:, event_type:, reason: nil, created_by_user:
+    @reason = reason
+    super(record: page, event_type:, created_by_user:)
+  end
+
+  private
+
+  def version_class = WikiVersion
+  def version_association = :wiki_versions
+  def record_key = :wiki_page
+
+  def snapshot_attributes = {
+      title: @record.title,
+      body: @record.body,
+      reason: @reason }
+end

backend/app/services/youtube/api_client.rb

@@ -0,0 +1,73 @@
+require 'json'
+require 'net/http'
+require 'uri'
+
+
+module Youtube
+  class ApiClient
+    ENDPOINT = 'https://www.googleapis.com/youtube/v3'
+
+    def initialize api_key: ENV.fetch('YOUTUBE_API_KEY')
+      @api_key = api_key
+    end
+
+    def search_videos q:, published_after: nil, published_before: nil, page_token: nil
+      get_json('/search', {
+          part:           'snippet',
+          type:           'video',
+          q:,
+          order:          'date',
+          maxResults:     50,
+          regionCode:     'JP',
+          relevanceLanguage: 'ja',
+          publishedAfter: published_after&.iso8601,
+          publishedBefore: published_before&.iso8601,
+          pageToken:      page_token }.compact)
+    end
+
+    def videos ids
+      return { 'items' => [] } if ids.empty?
+
+      get_json('/videos', part: 'snippet,status,contentDetails', id: ids.join(','))
+    end
+
+    def playlist_items playlist_id:, page_token: nil
+      get_json('/playlistItems', {
+          part:       'snippet,contentDetails,status',
+          playlistId: playlist_id,
+          maxResults: 50,
+          pageToken:  page_token }.compact)
+    end
+
+    def channel id: nil, handle: nil
+      raise ArgumentError, 'id or handle is required' if id.present? == handle.present?
+
+      params = { part: 'snippet,contentDetails' }
+      params[:id] = id if id.present?
+      params[:forHandle] = handle if handle.present?
+
+      get_json('/channels', params)
+    end
+
+    private
+
+    def get_json path, params
+      uri = URI(ENDPOINT + path)
+      uri.query = URI.encode_www_form(params.merge(key: @api_key))
+
+      response = Net::HTTP.start(uri.host,
+                                 uri.port,
+                                 use_ssl: true,
+                                 open_timeout: 10,
+                                 read_timeout: 30) do |http|
+        http.get(uri)
+      end
+
+      unless response.is_a?(Net::HTTPSuccess)
+        raise "YouTube API error: #{ response.code } #{ response.body }"
+      end
+
+      JSON.parse(response.body)
+    end
+  end
+end

backend/app/services/youtube/sync.rb

@@ -0,0 +1,168 @@
+require 'open-uri'
+require 'set'
+require 'time'
+
+
+module Youtube
+  class Sync
+    def initialize client: ApiClient.new
+      @client = client
+    end
+
+    def sync!
+      video_ids = discover_video_ids
+      return if video_ids.empty?
+
+      video_ids.each_slice(50) do |ids|
+        @client.videos(ids).fetch('items', []).each do |item|
+          sync_video!(VideoItem.new(item))
+        end
+      end
+    end
+
+    private
+
+    def discover_video_ids
+      ids = Set.new
+
+      query_terms.each do |q|
+        response = @client.search_videos(q:, published_after: sync_since)
+
+        response.fetch('items', []).each do |item|
+          video_id = item.dig('id', 'videoId')
+          ids << video_id if video_id.present?
+        end
+      end
+
+      playlist_ids.each do |playlist_id|
+        each_playlist_item(playlist_id) do |item|
+          video_id = item.dig('contentDetails', 'videoId')
+          video_id ||= item.dig('snippet', 'resourceId', 'videoId')
+
+          ids << video_id if video_id.present?
+        end
+      end
+
+      ids.to_a
+    end
+
+    def sync_video! video
+      post = Post.where('url REGEXP ?', youtube_url_regexp(video.id)).first
+
+      original_created_from = video.published_at.change(sec: 0)
+      original_created_before = original_created_from + 1.minute
+
+      post_created = false
+      post_changed = false
+
+      if post
+        post.assign_attributes(title: video.title,
+                               original_created_from:,
+                               original_created_before:,
+                               thumbnail_base: video.thumbnail_url)
+
+        post_changed = post.changed?
+        post.save! if post_changed
+
+        attach_thumbnail_if_needed!(post, video.thumbnail_url)
+      else
+        post_created = true
+        post = Post.create!(
+            title: video.title,
+            url: video.url,
+            thumbnail_base: video.thumbnail_url,
+            uploaded_user_id: nil,
+            original_created_from:,
+            original_created_before:)
+
+        attach_thumbnail_if_needed!(post, video.thumbnail_url)
+
+        sync_post_tags!(post, [Tag.tagme.id, Tag.bot.id, Tag.youtube.id, Tag.video.id])
+      end
+
+      kept_tag_ids = post.tags.pluck(:id).to_set
+      desired_tag_ids = kept_tag_ids.to_a
+
+      deerjikist = Deerjikist.find_by(platform: :youtube, code: video.channel_id)
+      if deerjikist
+        desired_tag_ids.delete(Tag.no_deerjikist.id)
+        desired_tag_ids << deerjikist.tag_id
+      elsif post.tags.where(category: :deerjikist).none?
+        desired_tag_ids << Tag.no_deerjikist.id
+      end
+
+      desired_tag_ids.uniq!
+
+      sync_post_tags!(post, desired_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_tag_ids.to_set
+        PostVersionRecorder.ensure_snapshot!(post, created_by_user: nil)
+        PostVersionRecorder.record!(post:, event_type: :update, created_by_user: nil)
+      end
+    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
+
+      to_add = desired_tag_ids - current_tag_ids
+      to_remove = current_tag_ids - desired_tag_ids
+
+      Tag.where(id: to_add.to_a).find_each do |tag|
+        begin
+          PostTag.create!(post:, tag:)
+        rescue ActiveRecord::RecordNotUnique
+          ;
+        end
+      end
+
+      PostTag.where(post_id: post.id, tag_id: to_remove.to_a).kept.find_each do |pt|
+        pt.discard_by!(nil)
+      end
+    end
+
+    def attach_thumbnail_if_needed! post, thumbnail_url
+      return if post.thumbnail.attached?
+      return if thumbnail_url.blank?
+
+      post.thumbnail.attach(
+          io:           URI.open(thumbnail_url),
+          filename:     File.basename(URI.parse(thumbnail_url).path),
+          content_type: 'image/jpeg')
+
+      post.resized_thumbnail!
+    end
+
+    def youtube_url_regexp id
+      escaped = Regexp.escape(id)
+      "(youtube\\.com/watch\\?v=#{ escaped }|youtu\\.be/#{ escaped })([^A-Za-z0-9_-]|$)"
+    end
+
+    def query_terms = ['ぼざろクリーチャーシリーズ', '伊地知ニジカ', '伊地知虹鹿']
+
+    def playlist_ids
+      ['PLrOch4zHkI5vu29b-f9umUQQ4tQkuWLPX',
+       'PLrOch4zHkI5vOK0RaytQq6PbucxQkkL0K',
+       'PLrOch4zHkI5tdwm9vSegiDQJOM-hgpcOC']
+    end
+
+    def sync_since = 14.days.ago
+
+    def each_playlist_item playlist_id
+      page_token = nil
+
+      loop do
+        response = @client.playlist_items(playlist_id:, page_token:)
+
+        response.fetch('items', []).each do |item|
+          yield item
+        end
+
+        page_token = response['nextPageToken']
+        break if page_token.blank?
+      end
+    end
+  end
+end

backend/app/services/youtube/video_item.rb

@@ -0,0 +1,32 @@
+require 'time'
+
+
+module Youtube
+  class VideoItem
+    attr_reader :id, :title, :channel_id, :published_at, :thumbnail_url, :raw_tags
+
+    def initialize item
+      snippet = item.fetch('snippet')
+
+      @id = item.fetch('id')
+      @title = snippet['title']
+      @channel_id = snippet['channelId']
+      @published_at = Time.iso8601(snippet['publishedAt'])
+      @thumbnail_url = pick_thumbnail(snippet['thumbnails'] || { })
+      @raw_tags = snippet['tags'] || []
+    end
+
+    def url = "https://www.youtube.com/watch?v=#{ @id }"
+
+    private
+
+    def pick_thumbnail thumbnails
+      ['maxres', 'standard', 'high', 'medium', 'default'].each do |key|
+        url = thumbnails.dig(key, 'url')
+        return url if url.present?
+      end
+
+      nil
+    end
+  end
+end

backend/config/routes.rb

@@ -24,6 +24,7 @@ Rails.application.routes.draw do
       patch '', action: :update
 
       get :deerjikists
+      put :deerjikists, action: :update_deerjikists
     end
   end
 

backend/config/schedule.rb

@@ -17,3 +17,11 @@ every 1.day, at: '0:00 am' do
   rake 'post_similarity:calc', environment: 'production'
   rake 'tag_similarity:calc', environment: 'production'
 end
+
+every 1.day, at: '7:50 am' do
+  rake 'nico:export', environment: 'production'
+end
+
+every :hour do
+  rake 'post:sync', environment: 'production'
+end

backend/db/migrate/20260426120600_create_wiki_versions.rb

@@ -0,0 +1,91 @@
+class CreateWikiVersions < ActiveRecord::Migration[8.0]
+  class WikiPage < ActiveRecord::Base
+    self.table_name = 'wiki_pages'
+  end
+
+  class WikiRevision < ActiveRecord::Base
+    self.table_name = 'wiki_revisions'
+  end
+
+  class WikiRevisionLine < ActiveRecord::Base
+    self.table_name = 'wiki_revision_lines'
+  end
+
+  class WikiLine < ActiveRecord::Base
+    self.table_name = 'wiki_lines'
+  end
+
+  class WikiVersion < ActiveRecord::Base
+    self.table_name = 'wiki_versions'
+  end
+
+  class TagName < ActiveRecord::Base
+    self.table_name = 'tag_names'
+  end
+
+  def up
+    add_column :wiki_pages, :body, :text, after: :tag_name_id
+
+    create_table :wiki_versions do |t|
+      t.references :wiki_page, null: false, foreign_key: true
+      t.integer :version_no, null: false
+      t.string :event_type, null: false
+      t.string :title, null: false
+      t.text :body, null: false
+      t.text :reason
+      t.datetime :created_at, null: false
+      t.references :created_by_user, foreign_key: { to_table: :users }
+
+      t.index [:wiki_page_id, :version_no], unique: true
+      t.check_constraint 'version_no > 0',
+                         name: 'wiki_versions_version_no_positive'
+      t.check_constraint "event_type IN ('create', 'update', 'discard', 'restore')",
+                         name: 'wiki_versions_event_type_valid'
+    end
+
+    WikiPage.reset_column_information
+    WikiVersion.reset_column_information
+
+    say_with_time 'Backfilling wiki_versions' do
+      WikiPage.find_each do |page|
+        base_revision_id = nil
+        version_no = 1
+        title = TagName.find(page.tag_name_id).name
+        body = nil
+        loop do
+          rev = WikiRevision.where(wiki_page_id: page.id).find_by(base_revision_id:)
+          break unless rev
+
+          body = WikiRevisionLine.where(wiki_revision_id: rev.id).order(:position).map { |wrl|
+            WikiLine.find(wrl.wiki_line_id).body
+          }.join("\n")
+
+          WikiVersion.create!(
+              wiki_page_id: page.id,
+              version_no:,
+              event_type: version_no == 1 ? 'create' : 'update',
+              title:,
+              body:,
+              reason: rev.message,
+              created_at: rev.created_at,
+              created_by_user_id: rev.created_user_id)
+
+          version_no += 1
+          base_revision_id = rev.id
+        end
+        if body
+          page.update!(body:)
+        else
+          page.destroy!
+        end
+      end
+    end
+
+    change_column_null :wiki_pages, :body, false
+  end
+
+  def down
+    drop_table :wiki_versions
+    remove_column :wiki_pages, :body
+  end
+end

backend/db/migrate/20260427214800_create_post_implications.rb

@@ -0,0 +1,24 @@
+class CreatePostImplications < ActiveRecord::Migration[8.0]
+  def up
+    create_table :post_implications, primary_key: [:post_id, :parent_post_id] do |t|
+      t.references :post, null: false, foreign_key: true, index: false
+      t.references :parent_post, null: false, foreign_key: { to_table: :posts }
+      t.timestamps
+
+      t.check_constraint 'post_id <> parent_post_id',
+                         name: 'chk_post_implications_no_self'
+    end
+
+    add_column :post_versions, :parent_post_ids, :text, null: false, after: :parent_id
+    remove_column :post_versions, :parent_id, :bigint
+    remove_reference :posts, :parent, foreign_key: { to_table: :posts }
+  end
+
+  def down
+    add_reference :posts, :parent, foreign_key: { to_table: :posts }, after: :thumbnail_base
+    add_column :post_versions, :parent_id, :bigint, after: :post_id
+    remove_column :post_versions, :parent_post_ids, :text
+
+    drop_table :post_implications
+  end
+end

backend/db/migrate/20260501153900_rename_banned_to_banned_at_in_users_and_ip_addresses.rb

@@ -0,0 +1,16 @@
+class RenameBannedToBannedAtInUsersAndIpAddresses < ActiveRecord::Migration[8.0]
+  def up
+    [:users, :ip_addresses].each do
+      add_column _1, :banned_at, :datetime, after: :banned
+      add_index _1, :banned_at
+      remove_column _1, :banned
+    end
+  end
+
+  def down
+    [:ip_addresses, :users].each do
+      add_column _1, :banned, :boolean, null: false, default: false, after: :banned_at
+      remove_column _1, :banned_at
+    end
+  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_19_035400) do
+ActiveRecord::Schema[8.0].define(version: 2026_05_01_153900) 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
@@ -50,9 +50,10 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_19_035400) do
 
   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 "banned_at"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.index ["banned_at"], name: "index_ip_addresses_on_banned_at"
     t.index ["ip_address"], name: "index_ip_addresses_on_ip_address", unique: true
   end
 
@@ -119,6 +120,15 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_19_035400) do
     t.check_constraint "`version_no` > 0", name: "nico_tag_versions_version_no_positive"
   end
 
+  create_table "post_implications", primary_key: ["post_id", "parent_post_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "post_id", null: false
+    t.bigint "parent_post_id", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["parent_post_id"], name: "index_post_implications_on_parent_post_id"
+    t.check_constraint "`post_id` <> `parent_post_id`", name: "chk_post_implications_no_self"
+  end
+
   create_table "post_similarities", primary_key: ["post_id", "target_post_id"], charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "post_id", null: false
     t.bigint "target_post_id", null: false
@@ -155,13 +165,12 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_19_035400) do
     t.string "url", limit: 768, null: false
     t.string "thumbnail_base", limit: 2000
     t.text "tags", null: false
-    t.bigint "parent_id"
+    t.text "parent_post_ids", null: false
     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"
@@ -172,13 +181,11 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_19_035400) do
     t.string "title"
     t.string "url", limit: 768, null: false
     t.string "thumbnail_base", limit: 2000
-    t.bigint "parent_id"
     t.bigint "uploaded_user_id"
     t.datetime "created_at", null: false
     t.datetime "original_created_from"
     t.datetime "original_created_before"
     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
@@ -326,9 +333,10 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_19_035400) do
     t.string "name"
     t.string "inheritance_code", limit: 64, null: false
     t.string "role", null: false
-    t.boolean "banned", default: false, null: false
+    t.datetime "banned_at"
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.index ["banned_at"], name: "index_users_on_banned_at"
   end
 
   create_table "wiki_assets", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -354,6 +362,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_19_035400) do
 
   create_table "wiki_pages", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "tag_name_id", null: false
+    t.text "body", null: false
     t.bigint "created_user_id", null: false
     t.bigint "updated_user_id", null: false
     t.datetime "created_at", null: false
@@ -396,6 +405,22 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_19_035400) do
     t.index ["wiki_page_id"], name: "index_wiki_revisions_on_wiki_page_id"
   end
 
+  create_table "wiki_versions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "wiki_page_id", null: false
+    t.integer "version_no", null: false
+    t.string "event_type", null: false
+    t.string "title", null: false
+    t.text "body", null: false
+    t.text "reason"
+    t.datetime "created_at", null: false
+    t.bigint "created_by_user_id"
+    t.index ["created_by_user_id"], name: "index_wiki_versions_on_created_by_user_id"
+    t.index ["wiki_page_id", "version_no"], name: "index_wiki_versions_on_wiki_page_id_and_version_no", unique: true
+    t.index ["wiki_page_id"], name: "index_wiki_versions_on_wiki_page_id"
+    t.check_constraint "`event_type` in (_utf8mb4'create',_utf8mb4'update',_utf8mb4'discard',_utf8mb4'restore')", name: "wiki_versions_event_type_valid"
+    t.check_constraint "`version_no` > 0", name: "wiki_versions_version_no_positive"
+  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"
@@ -411,6 +436,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_19_035400) do
   add_foreign_key "nico_tag_relations", "tags", column: "nico_tag_id"
   add_foreign_key "nico_tag_versions", "tags"
   add_foreign_key "nico_tag_versions", "users", column: "created_by_user_id"
+  add_foreign_key "post_implications", "posts"
+  add_foreign_key "post_implications", "posts", column: "parent_post_id"
   add_foreign_key "post_similarities", "posts"
   add_foreign_key "post_similarities", "posts", column: "target_post_id"
   add_foreign_key "post_tags", "posts"
@@ -418,9 +445,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_19_035400) do
   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_implications", "tags"
@@ -453,4 +478,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_04_19_035400) do
   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"
+  add_foreign_key "wiki_versions", "users", column: "created_by_user_id"
+  add_foreign_key "wiki_versions", "wiki_pages"
 end

backend/lib/tasks/sync_posts.rake

@@ -0,0 +1,6 @@
+namespace :post do
+  desc '投稿同期（ニコニコ以外）'
+  task sync: :environment do
+    Youtube::Sync.new.sync!
+  end
+end

backend/spec/factories/ip_addresses.rb

@@ -0,0 +1,10 @@
+FactoryBot.define do
+  factory :ip_address do
+    ip_address { IPAddr.new('203.0.113.10').hton }
+    banned_at { nil }
+
+    trait :banned do
+      banned_at { Time.current }
+    end
+  end
+end

backend/spec/factories/users.rb

@@ -1,15 +1,24 @@
 FactoryBot.define do
   factory :user do
-    name { "test-user" }
+    name { nil }
     inheritance_code { SecureRandom.uuid }
-    role { "guest" }
+    role { 'guest' }
+    banned_at { nil }
+
+    trait :guest do
+      role { 'guest' }
+    end
 
     trait :member do
-      role { "member" }
+      role { 'member' }
     end
 
     trait :admin do
       role { 'admin' }
     end
+
+    trait :banned do
+      banned_at { Time.current }
+    end
   end
 end

backend/spec/factories/wiki_pages.rb

@@ -3,5 +3,7 @@ FactoryBot.define do
     title { "TestPage" }
     association :created_user, factory: :user
     association :updated_user, factory: :user
+
+    body { ' ' }
   end
 end

backend/spec/models/post_implication_spec.rb

@@ -0,0 +1,51 @@
+require 'rails_helper'
+
+RSpec.describe PostImplication, type: :model do
+  let!(:post_record) do
+    Post.create!(
+      title: 'post',
+      url: 'https://example.com/post-implication-post'
+    )
+  end
+
+  let!(:parent_post) do
+    Post.create!(
+      title: 'parent post',
+      url: 'https://example.com/post-implication-parent'
+    )
+  end
+
+  it 'is valid with post and parent_post' do
+    implication = described_class.new(
+      post: post_record,
+      parent_post:
+    )
+
+    expect(implication).to be_valid
+  end
+
+  it 'does not allow same post as parent_post' do
+    implication = described_class.new(
+      post: post_record,
+      parent_post: post_record
+    )
+
+    expect(implication).not_to be_valid
+    expect(implication.errors[:parent_post_id]).to be_present
+  end
+
+  it 'does not allow duplicate pair' do
+    described_class.create!(
+      post: post_record,
+      parent_post:
+    )
+
+    duplicate = described_class.new(
+      post: post_record,
+      parent_post:
+    )
+
+    expect(duplicate).not_to be_valid
+    expect(duplicate.errors[:post_id]).to be_present
+  end
+end

backend/spec/models/post_version_spec.rb

@@ -19,7 +19,7 @@ RSpec.describe PostVersion, type: :model do
       url: post_record.url,
       thumbnail_base: post_record.thumbnail_base,
       tags: post_record.snapshot_tag_names.join(' '),
-      parent: post_record.parent,
+      parent_post_ids: post_record.snapshot_parent_post_ids.join(' '),
       original_created_from: post_record.original_created_from,
       original_created_before: post_record.original_created_before,
       created_at: Time.current,

backend/spec/models/tag_spec.rb

@@ -107,11 +107,13 @@ RSpec.describe Tag, type: :model do
     context 'when the source tag_name has a wiki_page' do
       let!(:source_post_tag) { PostTag.create!(post: post_record, tag: source_tag) }
       let!(:wiki_page) do
-        WikiPage.create!(
+        admin = create_admin_user!
+
+        Wiki::Commit.create_content!(
             tag_name: source_tag_name,
-          created_user: create_admin_user!,
+            body: 'source wiki body',
-          updated_user: create_admin_user!
+            created_by_user: admin,
-        )
+            message: 'init')
       end
 
       it 'rolls back the transaction' do
@@ -159,7 +161,7 @@ RSpec.describe Tag, type: :model do
         url: post.url,
         thumbnail_base: post.thumbnail_base,
         tags: snapshot_tags(post),
-        parent: post.parent,
+        parent_post_ids: post.snapshot_parent_post_ids.join(' '),
         original_created_from: post.original_created_from,
         original_created_before: post.original_created_before,
         created_at: Time.current,

backend/spec/requests/posts_spec.rb

@@ -15,6 +15,31 @@ RSpec.describe 'Posts API', type: :request do
     Rack::Test::UploadedFile.new(StringIO.new('dummy'), 'image/jpeg', original_filename: 'dummy.jpg')
   end
 
+  def post_write_params params = { }
+    { parent_post_ids: '' }.merge(params)
+  end
+
+  def create_parent_post! title:, url:
+    Post.create!(title:, url:)
+  end
+
+  def create_post_version_for! post
+    PostVersion.create!(
+      post:,
+      version_no: 1,
+      event_type: 'create',
+      title: post.title,
+      url: post.url,
+      thumbnail_base: post.thumbnail_base,
+      tags: post.snapshot_tag_names.join(' '),
+      parent_post_ids: post.snapshot_parent_post_ids.join(' '),
+      original_created_from: post.original_created_from,
+      original_created_before: post.original_created_before,
+      created_at: post.created_at,
+      created_by_user: post.uploaded_user
+    )
+  end
+
   let!(:tag_name) { TagName.create!(name: 'spec_tag') }
   let!(:tag)      { Tag.create!(tag_name: tag_name, category: :general) }
 
@@ -457,6 +482,65 @@ RSpec.describe 'Posts API', type: :request do
         expect(json).to have_key('viewed')
         expect([true, false]).to include(json['viewed'])
       end
+
+      context 'when post has parent, child, and sibling posts' do
+        let!(:parent_post) do
+          create_parent_post!(
+            title: 'shared parent post',
+            url: 'https://example.com/shared-parent-post'
+          )
+        end
+
+        let!(:child_post) do
+          Post.create!(
+            title: 'child post',
+            url: 'https://example.com/show-child-post'
+          )
+        end
+
+        let!(:sibling_post) do
+          Post.create!(
+            title: 'sibling post',
+            url: 'https://example.com/show-sibling-post'
+          )
+        end
+
+        before do
+          PostImplication.create!(
+            post: post_record,
+            parent_post:
+          )
+
+          PostImplication.create!(
+            post: child_post,
+            parent_post: post_record
+          )
+
+          PostImplication.create!(
+            post: sibling_post,
+            parent_post:
+          )
+        end
+
+        it 'returns parent_posts, child_posts, and sibling_posts' do
+          get "/posts/#{post_record.id}"
+
+          expect(response).to have_http_status(:ok)
+
+          parent_ids = json.fetch('parent_posts').map { |p| p.fetch('id') }
+          child_ids = json.fetch('child_posts').map { |p| p.fetch('id') }
+
+          expect(parent_ids).to include(parent_post.id)
+          expect(child_ids).to include(child_post.id)
+
+          sibling_posts_by_parent = json.fetch('sibling_posts')
+          siblings = sibling_posts_by_parent.fetch(parent_post.id.to_s)
+
+          sibling_ids = siblings.map { |p| p.fetch('id') }
+          expect(sibling_ids).to include(post_record.id)
+          expect(sibling_ids).to include(sibling_post.id)
+        end
+      end
     end
 
     context 'when post does not exist' do
@@ -475,25 +559,28 @@ RSpec.describe 'Posts API', type: :request do
 
     it '401 when not logged in' do
       sign_out
-      post '/posts', params: { title: 't', url: 'https://example.com/x', tags: 'a', thumbnail: dummy_upload }
+      post '/posts', params: post_write_params(title: 't', url: 'https://example.com/x', tags: 'a',
+                                               thumbnail: dummy_upload)
+
       expect(response).to have_http_status(:unauthorized)
     end
 
     it '403 when not member' do
       sign_in_as(create(:user, role: 'guest'))
-      post '/posts', params: { title: 't', url: 'https://example.com/x', tags: 'a', thumbnail: dummy_upload }
+      post '/posts', params: post_write_params(title: 't', url: 'https://example.com/x', tags: 'a',
+                                               thumbnail: dummy_upload)
       expect(response).to have_http_status(:forbidden)
     end
 
     it '201 and creates post + tags when member' do
       sign_in_as(member)
 
-      post '/posts', params: {
+      post '/posts', params: post_write_params(
         title: 'new post',
         url: 'https://example.com/new',
         tags: 'spec_tag', # 既存タグ名を投げる
         thumbnail: dummy_upload
-      }
+      )
 
       expect(response).to have_http_status(:created)
       expect(json).to include('id', 'title', 'url')
@@ -507,12 +594,12 @@ RSpec.describe 'Posts API', type: :request do
     it '201 and creates post + tags when member and tags have aliases' do
       sign_in_as(member)
 
-      post '/posts', params: {
+      post '/posts', params: post_write_params(
         title: 'new post',
         url: 'https://example.com/new',
         tags: 'manko', # 既存タグ名を投げる
         thumbnail: dummy_upload
-      }
+      )
 
       expect(response).to have_http_status(:created)
       expect(json).to include('id', 'title', 'url')
@@ -533,13 +620,14 @@ RSpec.describe 'Posts API', type: :request do
       it 'return 400' do
         sign_in_as(member)
 
-        post '/posts', params: {
+        post '/posts', params: post_write_params(
           title: 'new post',
-            url: 'https://example.com/nico_tag',
+          url: 'https://example.com/nico-tag-post',
           tags: 'nico:nico_tag',
-            thumbnail: dummy_upload }
+          thumbnail: dummy_upload
+        )
 
-        expect(response).to have_http_status(:bad_request)
+        expect(response).to have_http_status(:bad_request), response.body
       end
     end
 
@@ -547,11 +635,11 @@ RSpec.describe 'Posts API', type: :request do
       it 'returns 422' do
         sign_in_as(member)
 
-        post '/posts', params: {
+        post '/posts', params: post_write_params(
             title: 'new post',
             url: '   ',
             tags: 'spec_tag', # 既存タグ名を投げる
-            thumbnail: dummy_upload }
+            thumbnail: dummy_upload)
 
         expect(response).to have_http_status(:unprocessable_entity)
       end
@@ -561,16 +649,156 @@ RSpec.describe 'Posts API', type: :request do
       it 'returns 422' do
         sign_in_as(member)
 
-        post '/posts', params: {
+        post '/posts', params: post_write_params(
             title: 'new post',
             url: 'ぼざクリタグ広場',
             tags: 'spec_tag', # 既存タグ名を投げる
-          thumbnail: dummy_upload
+            thumbnail: dummy_upload)
-        }
 
         expect(response).to have_http_status(:unprocessable_entity)
       end
     end
+
+    context 'when parent_post_ids is provided' do
+      let!(:parent_post_1) do
+        create_parent_post!(
+          title: 'parent post 1',
+          url: 'https://example.com/parent-post-1'
+        )
+      end
+
+      let!(:parent_post_2) do
+        create_parent_post!(
+          title: 'parent post 2',
+          url: 'https://example.com/parent-post-2'
+        )
+      end
+
+      it 'creates post implications for parent posts' do
+        sign_in_as(member)
+
+        expect {
+          post '/posts', params: {
+              title: 'child post',
+              url: 'https://example.com/child-post',
+              tags: 'spec_tag',
+              parent_post_ids: "#{parent_post_1.id} #{parent_post_2.id}",
+              thumbnail: dummy_upload }
+        }.to change(PostImplication, :count).by(2)
+
+        expect(response).to have_http_status(:created)
+
+        created_post = Post.find(json.fetch('id'))
+        expect(created_post.parent_posts.order(:id).pluck(:id)).to eq(
+          [parent_post_1.id, parent_post_2.id].sort
+        )
+
+        expect(PostImplication.exists?(
+          post_id: created_post.id,
+          parent_post_id: parent_post_1.id
+        )).to be(true)
+
+        expect(PostImplication.exists?(
+          post_id: created_post.id,
+          parent_post_id: parent_post_2.id
+        )).to be(true)
+      end
+
+      it 'deduplicates parent_post_ids' do
+        sign_in_as(member)
+
+        expect {
+          post '/posts', params: post_write_params(
+            title: 'dedup child post',
+            url: 'https://example.com/dedup-child-post',
+            tags: 'spec_tag',
+            parent_post_ids: "#{parent_post_1.id} #{parent_post_1.id}",
+            thumbnail: dummy_upload
+          )
+        }.to change(PostImplication, :count).by(1)
+
+        expect(response).to have_http_status(:created)
+
+        created_post = Post.find(json.fetch('id'))
+        expect(created_post.parent_posts.pluck(:id)).to eq([parent_post_1.id])
+      end
+
+      it 'records parent_post_ids in post version' do
+        sign_in_as(member)
+
+        post '/posts', params: post_write_params(
+          title: 'versioned child post',
+          url: 'https://example.com/versioned-child-post',
+          tags: 'spec_tag',
+          parent_post_ids: "#{parent_post_1.id} #{parent_post_2.id}",
+          thumbnail: dummy_upload
+        )
+
+        expect(response).to have_http_status(:created)
+
+        created_post = Post.find(json.fetch('id'))
+        version = PostVersion.find_by!(post: created_post, version_no: 1)
+
+        expect(version.parent_post_ids.split.map(&:to_i)).to eq(
+          [parent_post_1.id, parent_post_2.id].sort
+        )
+      end
+    end
+
+    context 'when parent_post_ids is missing' do
+      it 'returns 422' do
+        sign_in_as(member)
+
+        expect {
+          post '/posts', params: {
+              title: 'missing parent_post_ids',
+              url: 'https://example.com/missing-parent-post-ids',
+              tags: 'spec_tag',
+              thumbnail: dummy_upload }
+        }.not_to change(Post, :count)
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(json.fetch('errors')).to be_present
+      end
+    end
+
+    context 'when parent_post_ids includes invalid token' do
+      it 'returns 422 and does not create post' do
+        sign_in_as(member)
+
+        expect {
+          post '/posts', params: post_write_params(
+            title: 'invalid parent ids',
+            url: 'https://example.com/invalid-parent-ids',
+            tags: 'spec_tag',
+            parent_post_ids: 'abc',
+            thumbnail: dummy_upload
+          )
+        }.not_to change(Post, :count)
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(json.fetch('errors')).to be_present
+      end
+    end
+
+    context 'when parent_post_ids includes nonexistent post id' do
+      it 'returns 422 and does not create post implication' do
+        sign_in_as(member)
+
+        expect {
+          post '/posts', params: post_write_params(
+            title: 'missing parent post',
+            url: 'https://example.com/missing-parent-post',
+            tags: 'spec_tag',
+            parent_post_ids: '999999999',
+            thumbnail: dummy_upload
+          )
+        }.not_to change(PostImplication, :count)
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(json.fetch('errors')).to be_present
+      end
+    end
   end
 
   describe 'PUT /posts/:id' do
@@ -578,13 +806,13 @@ RSpec.describe 'Posts API', type: :request do
 
     it '401 when not logged in' do
       sign_out
-      put "/posts/#{post_record.id}", params: { title: 'updated', tags: 'spec_tag' }
+      put "/posts/#{post_record.id}", params: post_write_params(title: 'updated', tags: 'spec_tag')
       expect(response).to have_http_status(:unauthorized)
     end
 
     it '403 when not member' do
       sign_in_as(create(:user, role: 'guest'))
-      put "/posts/#{post_record.id}", params: { title: 'updated', tags: 'spec_tag' }
+      put "/posts/#{post_record.id}", params: post_write_params(title: 'updated', tags: 'spec_tag')
       expect(response).to have_http_status(:forbidden)
     end
 
@@ -595,10 +823,9 @@ RSpec.describe 'Posts API', type: :request do
       tn2 = TagName.create!(name: 'spec_tag_2')
       Tag.create!(tag_name: tn2, category: :general)
 
-      put "/posts/#{post_record.id}", params: {
+      put "/posts/#{post_record.id}", params: post_write_params(
           title: 'updated title',
-        tags: 'spec_tag_2'
+          tags: 'spec_tag_2')
-      }
 
       expect(response).to have_http_status(:ok)
       expect(json).to have_key('tags')
@@ -619,11 +846,178 @@ RSpec.describe 'Posts API', type: :request do
       it 'return 400' do
         sign_in_as(member)
 
+        put "/posts/#{post_record.id}", params: post_write_params(
+          title: 'updated title',
+          tags: 'nico:nico_tag'
+        )
+
+        expect(response).to have_http_status(:bad_request), response.body
+      end
+    end
+
+    context 'when parent_post_ids is provided' do
+      let!(:old_parent_post) do
+        create_parent_post!(
+          title: 'old parent post',
+          url: 'https://example.com/old-parent-post'
+        )
+      end
+
+      let!(:new_parent_post_1) do
+        create_parent_post!(
+          title: 'new parent post 1',
+          url: 'https://example.com/new-parent-post-1'
+        )
+      end
+
+      let!(:new_parent_post_2) do
+        create_parent_post!(
+          title: 'new parent post 2',
+          url: 'https://example.com/new-parent-post-2'
+        )
+      end
+
+      before do
+        PostImplication.create!(
+          post: post_record,
+          parent_post: old_parent_post
+        )
+      end
+
+      it 'replaces parent posts' do
+        sign_in_as(member)
+
+        put "/posts/#{post_record.id}", params: post_write_params(
+          title: 'updated title',
+          tags: 'spec_tag',
+          parent_post_ids: "#{new_parent_post_1.id} #{new_parent_post_2.id}"
+        )
+
+        expect(response).to have_http_status(:ok)
+
+        expect(post_record.reload.parent_posts.order(:id).pluck(:id)).to eq(
+          [new_parent_post_1.id, new_parent_post_2.id].sort
+        )
+
+        expect(PostImplication.exists?(
+          post_id: post_record.id,
+          parent_post_id: old_parent_post.id
+        )).to be(false)
+      end
+
+      it 'clears parent posts when parent_post_ids is blank' do
+        sign_in_as(member)
+
+        put "/posts/#{post_record.id}", params: post_write_params(
+          title: 'updated title',
+          tags: 'spec_tag',
+          parent_post_ids: ''
+        )
+
+        expect(response).to have_http_status(:ok)
+        expect(post_record.reload.parent_posts).to be_empty
+      end
+
+      it 'records changed parent_post_ids in post version' do
+        sign_in_as(member)
+        create_post_version_for!(post_record.reload)
+
+        put "/posts/#{post_record.id}", params: post_write_params(
+          title: 'updated title',
+          tags: 'spec_tag',
+          parent_post_ids: "#{new_parent_post_1.id} #{new_parent_post_2.id}"
+        )
+
+        expect(response).to have_http_status(:ok)
+
+        version = post_record.reload.post_versions.order(:version_no).last
+
+        expect(version.version_no).to eq(2)
+        expect(version.parent_post_ids.split.map(&:to_i)).to eq(
+          [new_parent_post_1.id, new_parent_post_2.id].sort
+        )
+      end
+    end
+
+    context 'when parent_post_ids is missing' do
+      it 'returns 422' do
+        sign_in_as(member)
+
         put "/posts/#{post_record.id}", params: {
             title: 'updated title',
-            tags: 'nico:nico_tag' }
+            tags: 'spec_tag' }
 
-        expect(response).to have_http_status(:bad_request)
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(json.fetch('errors')).to be_present
+      end
+    end
+
+    context 'when parent_post_ids includes invalid token' do
+      it 'returns 422 and does not change parent posts' do
+        sign_in_as(member)
+
+        parent_post = create_parent_post!(
+          title: 'valid parent post',
+          url: 'https://example.com/valid-parent-post'
+        )
+
+        PostImplication.create!(
+          post: post_record,
+          parent_post:
+        )
+
+        put "/posts/#{post_record.id}", params: post_write_params(
+          title: 'updated title',
+          tags: 'spec_tag',
+          parent_post_ids: 'abc'
+        )
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(post_record.reload.parent_posts.pluck(:id)).to eq([parent_post.id])
+      end
+    end
+
+    context 'when parent_post_ids includes nonexistent post id' do
+      it 'returns 422 and does not change parent posts' do
+        sign_in_as(member)
+
+        parent_post = create_parent_post!(
+          title: 'existing parent post',
+          url: 'https://example.com/existing-parent-post'
+        )
+
+        PostImplication.create!(
+          post: post_record,
+          parent_post:
+        )
+
+        put "/posts/#{post_record.id}", params: post_write_params(
+          title: 'updated title',
+          tags: 'spec_tag',
+          parent_post_ids: '999999999'
+        )
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(post_record.reload.parent_posts.pluck(:id)).to eq([parent_post.id])
+      end
+    end
+
+    context 'when parent_post_ids includes self id' do
+      it 'returns 422 and does not create self implication' do
+        sign_in_as(member)
+
+        put "/posts/#{post_record.id}", params: post_write_params(
+          title: 'updated title',
+          tags: 'spec_tag',
+          parent_post_ids: post_record.id.to_s
+        )
+
+        expect(response).to have_http_status(:unprocessable_entity)
+
+        expect(PostImplication.exists?(
+          post_id: post_record.id,
+          parent_post_id: post_record.id
+        )).to be(false)
       end
     end
   end
@@ -773,20 +1167,20 @@ RSpec.describe 'Posts API', type: :request do
       post.snapshot_tag_names.join(' ')
     end
 
-    def create_post_version!(post, version_no:, event_type:, created_by_user:, created_at:)
+    def create_post_version! post, version_no:, event_type:, created_by_user:, created_at:
       PostVersion.create!(
-        post: post,
+        post:,
-        version_no: version_no,
+        version_no:,
-        event_type: event_type,
+        event_type:,
         title: post.title,
         url: post.url,
         thumbnail_base: post.thumbnail_base,
         tags: snapshot_tags(post),
-        parent: post.parent,
+        parent_post_ids: post.snapshot_parent_post_ids.join(' '),
         original_created_from: post.original_created_from,
         original_created_before: post.original_created_before,
-        created_at: created_at,
+        created_at:,
-        created_by_user: created_by_user
+        created_by_user:
       )
     end
 
@@ -1015,33 +1409,15 @@ RSpec.describe 'Posts API', type: :request do
       post.snapshot_tag_names.join(' ')
     end
 
-    def create_post_version_for!(post)
-      PostVersion.create!(
-        post: post,
-        version_no: 1,
-        event_type: 'create',
-        title: post.title,
-        url: post.url,
-        thumbnail_base: post.thumbnail_base,
-        tags: snapshot_tags(post),
-        parent: post.parent,
-        original_created_from: post.original_created_from,
-        original_created_before: post.original_created_before,
-        created_at: post.created_at,
-        created_by_user: post.uploaded_user
-      )
-    end
-
     it 'creates version 1 on POST /posts' do
       sign_in_as(member)
 
       expect do
-        post '/posts', params: {
+        post '/posts', params: post_write_params(
             title: 'versioned post',
             url: 'https://example.com/versioned-post',
             tags: 'spec_tag',
-          thumbnail: dummy_upload
+            thumbnail: dummy_upload)
-        }
       end.to change(PostVersion, :count).by(1)
 
       expect(response).to have_http_status(:created)
@@ -1064,10 +1440,9 @@ RSpec.describe 'Posts API', type: :request do
       Tag.create!(tag_name: tag_name2, category: :general)
 
       expect do
-        put "/posts/#{post_record.id}", params: {
+        put "/posts/#{post_record.id}", params: post_write_params(
             title: 'updated title',
-          tags: 'spec_tag_2'
+            tags: 'spec_tag_2')
-        }
       end.to change(PostVersion, :count).by(1)
 
       expect(response).to have_http_status(:ok)
@@ -1087,10 +1462,9 @@ RSpec.describe 'Posts API', type: :request do
       create_post_version_for!(post_record.reload)
 
       expect {
-        put "/posts/#{post_record.id}", params: {
+        put "/posts/#{post_record.id}", params: post_write_params(
             title: post_record.title,
-          tags: 'spec_tag'
+            tags: 'spec_tag')
-        }
       }.not_to change(PostVersion, :count)
       expect(response).to have_http_status(:ok)
 
@@ -1104,12 +1478,11 @@ RSpec.describe 'Posts API', type: :request do
       sign_in_as(member)
 
       expect do
-        post '/posts', params: {
+        post '/posts', params: post_write_params(
             title: 'invalid post',
             url: 'ぼざクリタグ広場',
             tags: 'spec_tag',
-          thumbnail: dummy_upload
+            thumbnail: dummy_upload)
-        }
       end.not_to change(PostVersion, :count)
 
       expect(response).to have_http_status(:unprocessable_entity)
@@ -1120,12 +1493,11 @@ RSpec.describe 'Posts API', type: :request do
       create_post_version_for!(post_record)
 
       expect do
-        put "/posts/#{post_record.id}", params: {
+        put "/posts/#{post_record.id}", params: post_write_params(
             title: 'updated title',
             tags: 'spec_tag',
             original_created_from: Time.zone.local(2020, 1, 2, 0, 0, 0).iso8601,
-          original_created_before: Time.zone.local(2020, 1, 1, 0, 0, 0).iso8601
+            original_created_before: Time.zone.local(2020, 1, 1, 0, 0, 0).iso8601)
-        }
       end.not_to change(PostVersion, :count)
 
       expect(response).to have_http_status(:unprocessable_entity)
@@ -1139,12 +1511,11 @@ RSpec.describe 'Posts API', type: :request do
       sign_in_as(member)
 
       expect {
-        post '/posts', params: {
+        post '/posts', params: post_write_params(
             title: 'tag versioned post',
             url: 'https://example.com/tag-versioned-post',
             tags: 'spec_tag',
-          thumbnail: dummy_upload
+            thumbnail: dummy_upload)
-        }
       }.to change { tag.reload.tag_versions.count }.by(1)
 
       expect(response).to have_http_status(:created)
@@ -1164,10 +1535,9 @@ RSpec.describe 'Posts API', type: :request do
       tag2 = Tag.create!(tag_name: tag_name2, category: :general)
 
       expect {
-        put "/posts/#{post_record.id}", params: {
+        put "/posts/#{post_record.id}", params: post_write_params(
             title: 'updated title',
-          tags: 'spec_tag_2'
+            tags: 'spec_tag_2')
-        }
       }.to change { tag2.reload.tag_versions.count }.by(1)
 
       expect(response).to have_http_status(:ok)

backend/spec/requests/tag_versions_spec.rb

@@ -214,5 +214,30 @@ RSpec.describe 'TagVersions API', type: :request do
       expect(versions.size).to eq(1)
       expect(versions.first['version_no']).to eq(2)
     end
+
+    it 'does not create tag versions by wiki updates when tag has no versions yet' do
+      wiki_tag_name = TagName.create!(name: 'tag_versions_from_wiki')
+      wiki_tag = Tag.create!(tag_name: wiki_tag_name, category: :general)
+
+      wiki_page =
+          Wiki::Commit.create_content!(
+              tag_name: wiki_tag_name,
+              body: 'before',
+              created_by_user: member,
+              message: 'init')
+
+      Wiki::Commit.content!(
+          page: wiki_page,
+          body: 'after',
+          created_user: member,
+          message: 'edit',
+          base_revision_id: wiki_page.current_revision.id)
+
+      get '/tags/versions', params: { id: wiki_tag.id }
+
+      expect(response).to have_http_status(:ok)
+      expect(json.fetch('versions')).to eq([])
+      expect(json.fetch('count')).to eq(0)
+    end
   end
 end

backend/spec/requests/tag_wiki_history_integrity_spec.rb

@@ -0,0 +1,160 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag and wiki history integrity', type: :request do
+  let(:member_user) { create(:user, role: 'member') }
+
+  def stub_current_user user
+    allow_any_instance_of(ApplicationController).to receive(:current_user).and_return(user)
+  end
+
+  def create_tag! name:, category: :general
+    tag_name = TagName.create!(name:)
+    Tag.create!(tag_name:, category:)
+  end
+
+  def create_wiki_for_tag! tag:, body: 'wiki body', user: member_user
+    Wiki::Commit.create_content!(
+        tag_name: tag.tag_name,
+        body:,
+        created_by_user: user,
+        message: 'init')
+  end
+
+  before do
+    stub_current_user(member_user)
+  end
+
+  describe 'PATCH /tags/:id' do
+    it 'records wiki_version when tag name changes and tag has wiki' do
+      tag = create_tag!(name: 'patch_tag_wiki_before')
+      wiki_page = create_wiki_for_tag!(tag:, body: 'wiki body before')
+
+      expect {
+        patch "/tags/#{ tag.id }", params: {
+          name: 'patch_tag_wiki_after',
+        }
+      }
+          .to change(TagVersion, :count).by(2)
+          .and change(WikiVersion, :count).by(1)
+
+      expect(response).to have_http_status(:ok)
+
+      tag.reload
+      wiki_page.reload
+      version = wiki_page.wiki_versions.order(:version_no).last
+
+      expect(tag.name).to eq('patch_tag_wiki_after')
+      expect(wiki_page.title).to eq('patch_tag_wiki_after')
+
+      expect(version).to have_attributes(
+        event_type: 'update',
+        title: 'patch_tag_wiki_after',
+        body: 'wiki body before',
+        created_by_user_id: member_user.id
+      )
+    end
+
+    it 'does not record wiki_version when only category changes' do
+      tag = create_tag!(name: 'patch_tag_category_only')
+      wiki_page = create_wiki_for_tag!(tag:, body: 'wiki body before')
+
+      before_wiki_versions = wiki_page.wiki_versions.count
+
+      expect {
+        patch "/tags/#{ tag.id }", params: {
+          category: 'meme',
+        }
+      }
+          .to change(TagVersion, :count).by(2)
+
+      expect(response).to have_http_status(:ok)
+
+      tag.reload
+      wiki_page.reload
+
+      expect(tag.name).to eq('patch_tag_category_only')
+      expect(tag.category).to eq('meme')
+      expect(wiki_page.wiki_versions.count).to eq(before_wiki_versions)
+    end
+  end
+
+  describe 'PUT /tags/:id' do
+    it 'records wiki_version when tag name changes and tag has wiki' do
+      tag = create_tag!(name: 'put_tag_wiki_before')
+      wiki_page = create_wiki_for_tag!(tag:, body: 'wiki body before')
+
+      expect {
+        put "/tags/#{ tag.id }", params: {
+          name: 'put_tag_wiki_after',
+          category: 'general',
+          aliases: '',
+          parent_tags: '',
+        }
+      }
+          .to change(TagVersion, :count).by(2)
+          .and change(WikiVersion, :count).by(1)
+
+      expect(response).to have_http_status(:ok)
+
+      tag.reload
+      wiki_page.reload
+      version = wiki_page.wiki_versions.order(:version_no).last
+
+      expect(tag.name).to eq('put_tag_wiki_after')
+      expect(wiki_page.title).to eq('put_tag_wiki_after')
+
+      expect(version).to have_attributes(
+        event_type: 'update',
+        title: 'put_tag_wiki_after',
+        body: 'wiki body before',
+        created_by_user_id: member_user.id
+      )
+    end
+
+    it 'does not record wiki_version when only category changes' do
+      tag = create_tag!(name: 'put_tag_category_only')
+      wiki_page = create_wiki_for_tag!(tag:, body: 'wiki body before')
+
+      before_wiki_versions = wiki_page.wiki_versions.count
+
+      expect {
+        put "/tags/#{ tag.id }", params: {
+          name: 'put_tag_category_only',
+          category: 'meme',
+          aliases: '',
+          parent_tags: '',
+        }
+      }
+          .to change(TagVersion, :count).by(2)
+
+      expect(response).to have_http_status(:ok)
+
+      tag.reload
+      wiki_page.reload
+
+      expect(tag.name).to eq('put_tag_category_only')
+      expect(tag.category).to eq('meme')
+      expect(wiki_page.wiki_versions.count).to eq(before_wiki_versions)
+    end
+
+    it 'does not record wiki_version when only aliases change' do
+      tag = create_tag!(name: 'put_tag_alias_only')
+      wiki_page = create_wiki_for_tag!(tag:, body: 'wiki body before')
+
+      before_wiki_versions = wiki_page.wiki_versions.count
+
+      expect {
+        put "/tags/#{ tag.id }", params: {
+          name: 'put_tag_alias_only',
+          category: 'general',
+          aliases: 'put_tag_alias_only_alias',
+          parent_tags: '',
+        }
+      }
+          .to change(TagVersion, :count).by(2)
+
+      expect(response).to have_http_status(:ok)
+      expect(wiki_page.reload.wiki_versions.count).to eq(before_wiki_versions)
+    end
+  end
+end

backend/spec/requests/tags_deerjikists_spec.rb

@@ -8,8 +8,10 @@ RSpec.describe 'Tags deerjikists API', type: :request do
 
   let!(:tag) { create(:tag, category: :deerjikist) }
 
+  let(:member) { create(:user, :member) }
+  let(:guest) { create(:user, role: :guest) }
+
   before do
-    # show_by_name / deerjikists_by_name 用に名前を固定
     tag.tag_name.update!(name: 'deerjika')
   end
 
@@ -21,10 +23,20 @@ RSpec.describe 'Tags deerjikists API', type: :request do
     let(:tag_id) { tag.id }
 
     context 'when tag exists and has no deerjikists' do
-      it 'returns 200 and empty array' do
+      it 'returns 200 with tag and empty deerjikists array' do
         do_request
+
         expect(response).to have_http_status(:ok)
-        expect(json).to eq([])
+
+        expect(json).to be_a(Hash)
+
+        expect(json['tag']).to be_a(Hash)
+        expect(json['tag']['id']).to eq(tag.id)
+        expect(json['tag']['name']).to eq('deerjika')
+        expect(json['tag']['category']).to eq('deerjikist')
+        expect(json['tag']['has_deerjikists']).to eq(false)
+
+        expect(json['deerjikists']).to eq([])
       end
     end
 
@@ -34,14 +46,24 @@ RSpec.describe 'Tags deerjikists API', type: :request do
         Deerjikist.create!(platform: platform2, code: code2, tag: tag)
       end
 
-      it 'returns 200 and deerjikists array' do
+      it 'returns 200 with tag and deerjikists array' do
         do_request
+
         expect(response).to have_http_status(:ok)
 
-        expect(json).to be_a(Array)
+        expect(json).to be_a(Hash)
-        expect(json.size).to eq(2)
 
-        expect(json.map { |h| [h['platform'], h['code']] }).to contain_exactly(
+        expect(json['tag']).to be_a(Hash)
+        expect(json['tag']['id']).to eq(tag.id)
+        expect(json['tag']['name']).to eq('deerjika')
+        expect(json['tag']['category']).to eq('deerjikist')
+        expect(json['tag']['has_deerjikists']).to eq(true)
+
+        expect(json['deerjikists']).to be_a(Array)
+        expect(json['deerjikists'].size).to eq(2)
+
+        expect(json['deerjikists'].map { |h| [h['platform'], h['code']] })
+          .to contain_exactly(
             [platform1, code1],
             [platform2, code2],
           )
@@ -53,6 +75,7 @@ RSpec.describe 'Tags deerjikists API', type: :request do
 
       it 'returns 404' do
         do_request
+
         expect(response).to have_http_status(:not_found)
       end
     end
@@ -70,6 +93,7 @@ RSpec.describe 'Tags deerjikists API', type: :request do
 
       it 'returns 400' do
         do_request
+
         expect(response).to have_http_status(:bad_request)
       end
     end
@@ -79,23 +103,209 @@ RSpec.describe 'Tags deerjikists API', type: :request do
 
       it 'returns 404' do
         do_request
+
         expect(response).to have_http_status(:not_found)
       end
     end
 
+    context 'when tag exists and has no deerjikists' do
+      it 'returns 200 with tag and empty deerjikists array' do
+        do_request
+
+        expect(response).to have_http_status(:ok)
+
+        expect(json).to be_a(Hash)
+
+        expect(json['tag']).to be_a(Hash)
+        expect(json['tag']['id']).to eq(tag.id)
+        expect(json['tag']['name']).to eq('deerjika')
+        expect(json['tag']['category']).to eq('deerjikist')
+        expect(json['tag']['has_deerjikists']).to eq(false)
+
+        expect(json['deerjikists']).to eq([])
+      end
+    end
+
     context 'when tag exists and has deerjikists' do
       before do
         Deerjikist.create!(platform: platform1, code: code1, tag: tag)
       end
 
-      it 'returns 200 and deerjikists array' do
+      it 'returns 200 with tag and deerjikists array' do
         do_request
+
+        expect(response).to have_http_status(:ok)
+
+        expect(json).to be_a(Hash)
+
+        expect(json['tag']).to be_a(Hash)
+        expect(json['tag']['id']).to eq(tag.id)
+        expect(json['tag']['name']).to eq('deerjika')
+        expect(json['tag']['category']).to eq('deerjikist')
+        expect(json['tag']['has_deerjikists']).to eq(true)
+
+        expect(json['deerjikists']).to be_a(Array)
+        expect(json['deerjikists'].size).to eq(1)
+
+        expect(json['deerjikists'][0]['platform']).to eq(platform1)
+        expect(json['deerjikists'][0]['code']).to eq(code1)
+      end
+    end
+  end
+
+  describe 'PUT /tags/:id/deerjikists' do
+    subject(:do_request) do
+      put "/tags/#{tag_id}/deerjikists", params: payload, as: :json
+    end
+
+    let(:tag_id) { tag.id }
+    let(:payload) do
+      [
+        { platform: platform1, code: code1 },
+        { platform: platform2, code: code2 },
+      ]
+    end
+
+    context 'when not logged in' do
+      it 'returns 401' do
+        do_request
+
+        expect(response).to have_http_status(:unauthorized)
+      end
+    end
+
+    context 'when logged in but not member' do
+      before do
+        sign_in_as guest
+      end
+
+      it 'returns 403' do
+        do_request
+
+        expect(response).to have_http_status(:forbidden)
+      end
+    end
+
+    context 'when tag does not exist' do
+      let(:tag_id) { 9_999_999 }
+
+      before do
+        sign_in_as member
+      end
+
+      it 'returns 404' do
+        do_request
+
+        expect(response).to have_http_status(:not_found)
+      end
+    end
+
+    context 'when logged in as member' do
+      before do
+        sign_in_as member
+      end
+
+      context 'when tag has no deerjikists' do
+        it 'creates deerjikists and returns deerjikists array' do
+          expect {
+            do_request
+          }.to change { Deerjikist.where(tag: tag).count }.from(0).to(2)
+
           expect(response).to have_http_status(:ok)
 
+          expect(json).to be_a(Array)
+          expect(json.map { |h| [h['platform'], h['code']] })
+            .to contain_exactly(
+              [platform1, code1],
+              [platform2, code2],
+            )
+
+          expect(Deerjikist.where(tag: tag).map { |d| [d.platform, d.code] })
+            .to contain_exactly(
+              [platform1, code1],
+              [platform2, code2],
+            )
+        end
+      end
+
+      context 'when tag already has deerjikists' do
+        before do
+          Deerjikist.create!(platform: platform1, code: 'old-code-1', tag: tag)
+          Deerjikist.create!(platform: platform2, code: 'old-code-2', tag: tag)
+        end
+
+        it 'replaces deerjikists and returns deerjikists array' do
+          do_request
+
+          expect(response).to have_http_status(:ok)
+
+          expect(Deerjikist.where(tag: tag).map { |d| [d.platform, d.code] })
+            .to contain_exactly(
+              [platform1, code1],
+              [platform2, code2],
+            )
+
+          expect(Deerjikist.exists?(platform: platform1, code: 'old-code-1')).to eq(false)
+          expect(Deerjikist.exists?(platform: platform2, code: 'old-code-2')).to eq(false)
+
+          expect(json).to be_a(Array)
+          expect(json.map { |h| [h['platform'], h['code']] })
+            .to contain_exactly(
+              [platform1, code1],
+              [platform2, code2],
+            )
+        end
+      end
+
+      context 'when payload is empty array' do
+        let(:payload) { [] }
+
+        before do
+          Deerjikist.create!(platform: platform1, code: code1, tag: tag)
+          Deerjikist.create!(platform: platform2, code: code2, tag: tag)
+        end
+
+        it 'clears deerjikists and returns empty array' do
+          expect {
+            do_request
+          }.to change { Deerjikist.where(tag: tag).count }.from(2).to(0)
+
+          expect(response).to have_http_status(:ok)
+          expect(json).to eq([])
+        end
+      end
+
+      context 'when youtube code is handle' do
+        let(:channel_id) { 'UCabcdefghijklmnopqrstuv' }
+        let(:payload) do
+          [
+            { platform: 'youtube', code: '@deerjika' },
+          ]
+        end
+
+        before do
+          allow(Net::HTTP).to receive(:get).and_return(
+            %(<link rel="canonical" href="https://www.youtube.com/channel/#{channel_id}">),
+          )
+        end
+
+        it 'normalises youtube handle to channel id' do
+          expect {
+            do_request
+          }.to change { Deerjikist.where(tag: tag).count }.from(0).to(1)
+
+          expect(response).to have_http_status(:ok)
+
+          expect(Net::HTTP).to have_received(:get)
+
+          expect(Deerjikist.exists?(platform: 'youtube', code: channel_id, tag: tag))
+            .to eq(true)
+
           expect(json).to be_a(Array)
           expect(json.size).to eq(1)
-        expect(json[0]['platform']).to eq(platform1)
+          expect(json[0]['platform']).to eq('youtube')
-        expect(json[0]['code']).to eq(code1)
+          expect(json[0]['code']).to eq(channel_id)
+        end
       end
     end
   end

backend/spec/requests/tags_spec.rb

@@ -471,6 +471,54 @@ RSpec.describe 'Tags API', type: :request do
         expect(response).to have_http_status(:unprocessable_entity)
         expect(nico_tag.reload.category).to eq('nico')
       end
+
+      it 'PATCH で tag の name を変更すると対応する wiki version を作成する' do
+        wiki_page =
+            Wiki::Commit.create_content!(
+                tag_name: tag.tag_name,
+                body: 'wiki body before',
+                created_by_user: member_user,
+                message: 'init')
+
+        expect {
+          patch "/tags/#{ tag.id }", params: {
+            name: 'patch_wiki_renamed_tag',
+          }
+        }
+            .to change(TagVersion, :count).by(2)
+            .and change(WikiVersion, :count).by(1)
+
+        expect(response).to have_http_status(:ok)
+
+        version = wiki_page.reload.wiki_versions.order(:version_no).last
+
+        expect(version).to have_attributes(
+          event_type: 'update',
+          title: 'patch_wiki_renamed_tag',
+          body: 'wiki body before',
+          created_by_user_id: member_user.id
+        )
+      end
+
+      it 'tag の category だけを変更しても wiki version は作成しない' do
+        wiki_page =
+            Wiki::Commit.create_content!(
+                tag_name: tag.tag_name,
+                body: 'wiki body before',
+                created_by_user: member_user,
+                message: 'init')
+
+        before_wiki_version_count = wiki_page.reload.wiki_versions.count
+
+        expect {
+          patch "/tags/#{ tag.id }", params: {
+            category: 'meme',
+          }
+        }.to change(TagVersion, :count).by(2)
+
+        expect(response).to have_http_status(:ok)
+        expect(wiki_page.reload.wiki_versions.count).to eq(before_wiki_version_count)
+      end
     end
   end
 
@@ -876,6 +924,134 @@ RSpec.describe 'Tags API', type: :request do
         expect(system_tag.reload.name).to eq(old_name)
         expect(system_tag.category).to eq(old_category)
       end
+
+      it 'wiki を持つ tag を更新すると wiki version も作成する' do
+        wiki_page =
+            Wiki::Commit.create_content!(
+                tag_name: tag.tag_name,
+                body: 'wiki body before',
+                created_by_user: member_user,
+                message: 'init')
+
+        Wiki::Commit.content!(
+          page: wiki_page,
+          body: 'wiki body before',
+          created_user: member_user,
+          message: 'init'
+        )
+
+        expect {
+          put "/tags/#{ tag.id }", params: {
+            name: 'put_wiki_version_tag',
+            category: 'meme',
+            aliases: 'unko',
+            parent_tags: '',
+          }
+        }
+            .to change(TagVersion, :count).by(2)
+            .and change(WikiVersion, :count).by(1)
+
+        expect(response).to have_http_status(:ok)
+
+        version = wiki_page.reload.wiki_versions.order(:version_no).last
+
+        expect(version).to have_attributes(
+          event_type: 'update',
+          title: 'put_wiki_version_tag',
+          body: 'wiki body before',
+          created_by_user_id: member_user.id
+        )
+      end
+
+      it '別名を他 tag から奪った場合、奪はれた側の tag version も作成する' do
+        old_owner = Tag.create!(
+          tag_name: TagName.create!(name: 'put_alias_old_owner'),
+          category: :general
+        )
+        stolen_alias = TagName.create!(
+          name: 'put_stolen_alias',
+          canonical: old_owner.tag_name
+        )
+
+        expect(old_owner.tag_name.aliases.map(&:name)).to include('put_stolen_alias')
+
+        expect {
+          put "/tags/#{ tag.id }", params: {
+            name: 'spec_tag',
+            category: 'general',
+            aliases: 'unko put_stolen_alias',
+            parent_tags: '',
+          }
+        }
+            .to change { tag.reload.tag_versions.count }.by(2)
+            .and change { old_owner.reload.tag_versions.count }.by(2)
+
+        expect(response).to have_http_status(:ok)
+
+        expect(stolen_alias.reload.canonical).to eq(tag.tag_name)
+        expect(old_owner.reload.tag_name.aliases.map(&:name)).not_to include('put_stolen_alias')
+
+        old_owner_versions = old_owner.tag_versions.order(:version_no)
+
+        expect(old_owner_versions.first.event_type).to eq('create')
+        expect(old_owner_versions.first.aliases.split).to include('put_stolen_alias')
+
+        expect(old_owner_versions.second.event_type).to eq('update')
+        expect(old_owner_versions.second.aliases.split).not_to include('put_stolen_alias')
+      end
+
+      it 'parent_tags に指定すると循環する tag は 422 にする' do
+        pending '#332 で対応予定'
+
+        child = Tag.create!(
+          tag_name: TagName.create!(name: 'put_cycle_child'),
+          category: :general
+        )
+
+        TagImplication.create!(tag: child, parent_tag: tag)
+
+        put "/tags/#{ tag.id }", params: {
+          name: 'spec_tag',
+          category: 'general',
+          aliases: 'unko',
+          parent_tags: child.name,
+        }
+
+        expect(response).to have_http_status(:unprocessable_entity)
+
+        expect(TagImplication.where(tag:, parent_tag: child)).not_to exist
+      end
+
+      it 'tag の name を変更すると対応する wiki version を作成する' do
+        wiki_page =
+            Wiki::Commit.create_content!(
+                tag_name: tag.tag_name,
+                body: 'wiki body before',
+                created_by_user: member_user,
+                message: 'init')
+
+        expect {
+          put "/tags/#{ tag.id }", params: {
+            name: 'put_wiki_renamed_tag',
+            category: 'general',
+            aliases: 'unko',
+            parent_tags: '',
+          }
+        }
+            .to change(TagVersion, :count).by(2)
+            .and change(WikiVersion, :count).by(1)
+
+        expect(response).to have_http_status(:ok)
+
+        version = wiki_page.reload.wiki_versions.order(:version_no).last
+
+        expect(version).to have_attributes(
+          event_type: 'update',
+          title: 'put_wiki_renamed_tag',
+          body: 'wiki body before',
+          created_by_user_id: member_user.id
+        )
+      end
     end
   end
 end

backend/spec/requests/users_spec.rb

@@ -1,110 +1,266 @@
-require "rails_helper"
+require 'rails_helper'
 
+RSpec.describe 'Users', type: :request do
+  let(:remote_ip) { '203.0.113.10' }
 
-RSpec.describe "Users", type: :request do
+  before do
-  describe "POST /users" do
+    allow_any_instance_of(ActionDispatch::Request)
-    it "creates guest user and returns code" do
+      .to receive(:remote_ip)
-      post "/users"
+      .and_return(remote_ip)
-      expect(response).to have_http_status(:ok)
+  end
-      expect(json["code"]).to be_present
+
-      expect(json["user"]["role"]).to eq("guest")
+  def auth_headers(user)
+    { 'X-Transfer-Code' => user.inheritance_code }
+  end
+
+  describe 'POST /users' do
+    it 'creates guest user, IpAddress and UserIp, and returns code' do
+      expect {
+        post '/users'
+      }.to change(User, :count).by(1)
+        .and change(IpAddress, :count).by(1)
+        .and change(UserIp, :count).by(1)
+
+      expect(response).to have_http_status(:created)
+      expect(json['code']).to be_present
+      expect(json['user']['role']).to eq('guest')
+
+      user = User.last
+      ip_address = IpAddress.find_by(ip_address: IPAddr.new(remote_ip).hton)
+
+      expect(user.role).to eq('guest')
+      expect(ip_address).to be_present
+      expect(UserIp.exists?(user:, ip_address:)).to eq(true)
+    end
+
+    it 'returns 403 and does not create user when current IP address is banned' do
+      IpAddress.create!(
+        ip_address: IPAddr.new(remote_ip).hton,
+        banned_at: Time.current
+      )
+
+      expect {
+        post '/users'
+      }.not_to change(User, :count)
+
+      expect(response).to have_http_status(:forbidden)
+      expect(UserIp.count).to eq(0)
     end
   end
 
-  describe "POST /users/code/renew" do
+  describe 'POST /users/code/renew' do
-    it "returns 401 when not logged in" do
+    it 'returns 401 when not logged in' do
-      sign_out
+      post '/users/code/renew'
-      post "/users/code/renew"
-      expect(response).to have_http_status(:unauthorized)
-    end
-  end
 
-  describe "PUT /users/:id" do
-    let(:user) { create(:user, name: "old-name", role: "guest") }
-
-    it "returns 401 when current_user id mismatch" do
-      sign_in_as(create(:user))
-      put "/users/#{user.id}", params: { name: "new-name" }
       expect(response).to have_http_status(:unauthorized)
     end
 
-    it "returns 400 when name is blank" do
+    it 'returns 403 when current user is banned' do
-      sign_in_as(user)
+      user = create(:user, :banned)
-      put "/users/#{user.id}", params: { name: "   " }
+
+      post '/users/code/renew', headers: auth_headers(user)
+
+      expect(response).to have_http_status(:forbidden)
+    end
+
+    it 'returns 403 when current IP address is banned' do
+      user = create(:user)
+
+      IpAddress.create!(
+        ip_address: IPAddr.new(remote_ip).hton,
+        banned_at: Time.current
+      )
+
+      post '/users/code/renew', headers: auth_headers(user)
+
+      expect(response).to have_http_status(:forbidden)
+    end
+  end
+
+  describe 'PUT /users/:id' do
+    let(:user) { create(:user, name: 'old-name', role: 'guest') }
+
+    it 'returns 401 when current_user id mismatch' do
+      other_user = create(:user)
+
+      put "/users/#{user.id}",
+          params: { name: 'new-name' },
+          headers: auth_headers(other_user)
+
+      expect(response).to have_http_status(:unauthorized)
+    end
+
+    it 'returns 400 when name is blank' do
+      put "/users/#{user.id}",
+          params: { name: '   ' },
+          headers: auth_headers(user)
+
       expect(response).to have_http_status(:bad_request)
     end
 
-    it "updates name and returns 201 with user slice" do
+    it 'updates name and returns user slice' do
-      sign_in_as(user)
+      put "/users/#{user.id}",
-      put "/users/#{user.id}", params: { name: "new-name" }
+          params: { name: 'new-name' },
+          headers: auth_headers(user)
 
-      expect(response).to have_http_status(:created)
+      expect(response).to have_http_status(:ok)
-      expect(json["id"]).to eq(user.id)
+      expect(json['id']).to eq(user.id)
-      expect(json["name"]).to eq("new-name")
+      expect(json['name']).to eq('new-name')
 
       user.reload
-      expect(user.name).to eq("new-name")
+      expect(user.name).to eq('new-name')
+    end
+
+    it 'returns 403 when current user is banned' do
+      user.update!(banned_at: Time.current)
+
+      put "/users/#{user.id}",
+          params: { name: 'new-name' },
+          headers: auth_headers(user)
+
+      expect(response).to have_http_status(:forbidden)
+
+      user.reload
+      expect(user.name).to eq('old-name')
+    end
+
+    it 'returns 403 when current IP address is banned' do
+      IpAddress.create!(
+        ip_address: IPAddr.new(remote_ip).hton,
+        banned_at: Time.current
+      )
+
+      put "/users/#{user.id}",
+          params: { name: 'new-name' },
+          headers: auth_headers(user)
+
+      expect(response).to have_http_status(:forbidden)
+
+      user.reload
+      expect(user.name).to eq('old-name')
     end
   end
 
-  describe "POST /users/verify" do
+  describe 'POST /users/verify' do
-    it "returns valid:false when code not found" do
+    it 'returns valid:false when code not found' do
-      post "/users/verify", params: { code: "nope" }
+      post '/users/verify', params: { code: 'nope' }
+
       expect(response).to have_http_status(:ok)
-      expect(json["valid"]).to eq(false)
+      expect(json['valid']).to eq(false)
     end
 
-    it "creates IpAddress and UserIp, and returns valid:true with user slice" do
+    it 'returns 403 when current IP address is banned' do
-      user = create(:user, inheritance_code: SecureRandom.uuid, role: "guest")
+      user = create(:user, inheritance_code: SecureRandom.uuid, role: 'guest')
 
-      # request.remote_ip を固定
+      IpAddress.create!(
-      allow_any_instance_of(ActionDispatch::Request).to receive(:remote_ip).and_return("203.0.113.10")
+        ip_address: IPAddr.new(remote_ip).hton,
+        banned_at: Time.current
+      )
 
       expect {
-        post "/users/verify", params: { code: user.inheritance_code }
+        post '/users/verify', params: { code: user.inheritance_code }
+      }.not_to change(UserIp, :count)
+
+      expect(response).to have_http_status(:forbidden)
+    end
+
+    it 'returns 403 when verified user is banned' do
+      user = create(
+        :user,
+        :banned,
+        inheritance_code: SecureRandom.uuid,
+        role: 'guest'
+      )
+
+      expect {
+        post '/users/verify', params: { code: user.inheritance_code }
+      }.not_to change(UserIp, :count)
+
+      expect(response).to have_http_status(:forbidden)
+    end
+
+    it 'creates IpAddress and UserIp, and returns valid:true with user slice' do
+      user = create(:user, inheritance_code: SecureRandom.uuid, role: 'guest')
+
+      expect {
+        post '/users/verify', params: { code: user.inheritance_code }
       }.to change(UserIp, :count).by(1)
+        .and change(IpAddress, :count).by(1)
 
       expect(response).to have_http_status(:ok)
-      expect(json["valid"]).to eq(true)
+      expect(json['valid']).to eq(true)
-      expect(json["user"]["id"]).to eq(user.id)
+      expect(json['user']['id']).to eq(user.id)
-      expect(json["user"]["inheritance_code"]).to eq(user.inheritance_code)
+      expect(json['user']['inheritance_code']).to eq(user.inheritance_code)
-      expect(json["user"]["role"]).to eq("guest")
+      expect(json['user']['role']).to eq('guest')
 
-      # ついでに IpAddress もできてることを確認（ipの保存形式がバイナリでも count で見れる）
+      ip_address = IpAddress.find_by(ip_address: IPAddr.new(remote_ip).hton)
-      expect(IpAddress.count).to be >= 1
+      expect(ip_address).to be_present
+      expect(UserIp.exists?(user:, ip_address:)).to eq(true)
     end
 
-    it "is idempotent for same user+ip (does not create duplicate UserIp)" do
+    it 'is idempotent for same user and same IP address' do
-      user = create(:user, inheritance_code: SecureRandom.uuid, role: "guest")
+      user = create(:user, inheritance_code: SecureRandom.uuid, role: 'guest')
-      allow_any_instance_of(ActionDispatch::Request).to receive(:remote_ip).and_return("203.0.113.10")
 
-      post "/users/verify", params: { code: user.inheritance_code }
+      post '/users/verify', params: { code: user.inheritance_code }
       expect(response).to have_http_status(:ok)
 
       expect {
-        post "/users/verify", params: { code: user.inheritance_code }
+        post '/users/verify', params: { code: user.inheritance_code }
       }.not_to change(UserIp, :count)
 
       expect(response).to have_http_status(:ok)
-      expect(json["valid"]).to eq(true)
+      expect(json['valid']).to eq(true)
+    end
+
+    it 'creates another UserIp for same user and different IP address' do
+      user = create(:user, inheritance_code: SecureRandom.uuid, role: 'guest')
+
+      post '/users/verify', params: { code: user.inheritance_code }
+      expect(response).to have_http_status(:ok)
+
+      allow_any_instance_of(ActionDispatch::Request)
+        .to receive(:remote_ip)
+        .and_return('203.0.113.11')
+
+      expect {
+        post '/users/verify', params: { code: user.inheritance_code }
+      }.to change(UserIp, :count).by(1)
+
+      expect(response).to have_http_status(:ok)
+      expect(json['valid']).to eq(true)
     end
   end
 
-  describe "GET /users/me" do
+  describe 'GET /users/me' do
-    it "returns 404 when code not found" do
+    it 'returns 404 when code not found' do
-      get "/users/me", params: { code: "nope" }
+      get '/users/me', params: { code: 'nope' }
+
       expect(response).to have_http_status(:not_found)
     end
 
-    it "returns user slice when found" do
+    it 'returns user slice when found' do
-      user = create(:user, inheritance_code: SecureRandom.uuid, name: "me", role: "guest")
+      user = create(:user, inheritance_code: SecureRandom.uuid, name: 'me', role: 'guest')
-      get "/users/me", params: { code: user.inheritance_code }
+
+      get '/users/me', params: { code: user.inheritance_code }
 
       expect(response).to have_http_status(:ok)
-      expect(json["id"]).to eq(user.id)
+      expect(json['id']).to eq(user.id)
-      expect(json["name"]).to eq("me")
+      expect(json['name']).to eq('me')
-      expect(json["inheritance_code"]).to eq(user.inheritance_code)
+      expect(json['inheritance_code']).to eq(user.inheritance_code)
-      expect(json["role"]).to eq("guest")
+      expect(json['role']).to eq('guest')
+    end
+
+    it 'returns 403 when current IP address is banned' do
+      user = create(:user, inheritance_code: SecureRandom.uuid)
+
+      IpAddress.create!(
+        ip_address: IPAddr.new(remote_ip).hton,
+        banned_at: Time.current
+      )
+
+      get '/users/me', params: { code: user.inheritance_code }
+
+      expect(response).to have_http_status(:forbidden)
     end
   end
 end

backend/spec/requests/wiki_body_search_pending_spec.rb

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

backend/spec/requests/wiki_conflict_spec.rb

@@ -0,0 +1,42 @@
+require 'rails_helper'
+
+RSpec.describe 'Wiki conflict handling', type: :request do
+  let!(:user) { create_member_user! }
+
+  def auth_headers user
+    { 'X-Transfer-Code' => user.inheritance_code }
+  end
+
+  it 'returns 409 when base_revision_id is stale' do
+    page =
+        Wiki::Commit.create_content!(
+            tag_name: TagName.create!(name: 'wiki_conflict_request'),
+            body: 'first',
+            created_by_user: user,
+            message: 'init')
+
+    stale_id = page.current_revision.id
+
+    Wiki::Commit.content!(
+        page:,
+        body: 'second',
+        created_user: user,
+        message: 'other edit',
+        base_revision_id: stale_id)
+
+    put "/wiki/#{ page.id }",
+        params: {
+          title: 'wiki_conflict_request',
+          body: 'third',
+          message: 'stale',
+          base_revision_id: stale_id,
+        },
+        headers: auth_headers(user)
+
+    expect(response).to have_http_status(:conflict)
+
+    page.reload
+    expect(page.body).to eq('second')
+    expect(page.current_revision.message).to eq('other edit')
+  end
+end

backend/spec/requests/wiki_history_integrity_spec.rb

@@ -0,0 +1,196 @@
+require 'cgi'
+require 'rails_helper'
+
+RSpec.describe 'Wiki history integrity', type: :request do
+  let!(:user) { create_member_user! }
+
+  def auth_headers user
+    { 'X-Transfer-Code' => user.inheritance_code }
+  end
+
+  def create_wiki_page title:, body: 'body', message: 'init', user: self.user
+    Wiki::Commit.create_content!(
+        tag_name: TagName.create!(name: title),
+        body:,
+        created_by_user: user,
+        message:)
+  end
+
+  describe 'POST /wiki' do
+    it 'creates wiki_page, wiki_revision, and wiki_version atomically' do
+      expect {
+        post '/wiki',
+             params: {
+               title: 'wiki_history_create_atomic',
+               body: "a\nb\nc",
+               message: 'initial commit',
+             },
+             headers: auth_headers(user)
+      }
+          .to change(WikiPage, :count).by(1)
+          .and change(WikiRevision, :count).by(1)
+          .and change(WikiVersion, :count).by(1)
+
+      expect(response).to have_http_status(:created)
+
+      page = WikiPage.find(json.fetch('id'))
+      revision = page.current_revision
+      version = page.wiki_versions.order(:version_no).last
+
+      expect(page.title).to eq('wiki_history_create_atomic')
+      expect(page.body).to eq("a\nb\nc")
+
+      expect(revision).to be_content
+      expect(revision.message).to eq('initial commit')
+      expect(revision.lines_count).to eq(3)
+
+      expect(version).to have_attributes(
+        version_no: 1,
+        event_type: 'create',
+        title: 'wiki_history_create_atomic',
+        body: "a\nb\nc",
+        reason: 'initial commit',
+        created_by_user_id: user.id
+      )
+    end
+
+    it 'returns 422 and creates nothing when normalised body is blank' do
+      expect {
+        post '/wiki',
+             params: {
+               title: 'wiki_history_blank_body',
+               body: "\r\n\r\n",
+               message: 'blank',
+             },
+             headers: auth_headers(user)
+      }
+          .not_to change(WikiPage, :count)
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(WikiPage.joins(:tag_name).where(tag_names: { name: 'wiki_history_blank_body' })).not_to exist
+    end
+
+    it 'returns 422 and creates no partial page when title already exists' do
+      create_wiki_page(title: 'wiki_history_duplicate_title', body: 'first')
+
+      expect {
+        post '/wiki',
+             params: {
+               title: 'wiki_history_duplicate_title',
+               body: 'second',
+               message: 'duplicate',
+             },
+             headers: auth_headers(user)
+      }
+          .not_to change(WikiPage, :count)
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(WikiPage.joins(:tag_name).where(tag_names: { name: 'wiki_history_duplicate_title' }).count).to eq(1)
+    end
+  end
+
+  describe 'PUT /wiki/:id' do
+    it 'updates body and records wiki_revision and wiki_version' do
+      page = create_wiki_page(title: 'wiki_history_update_body', body: 'before')
+      current_id = page.current_revision.id
+
+      expect {
+        put "/wiki/#{ page.id }",
+            params: {
+              title: 'wiki_history_update_body',
+              body: 'after',
+              message: 'edit body',
+              base_revision_id: current_id,
+            },
+            headers: auth_headers(user)
+      }
+          .to change(WikiRevision, :count).by(1)
+          .and change(WikiVersion, :count).by(1)
+
+      expect(response).to have_http_status(:ok)
+
+      page.reload
+      version = page.wiki_versions.order(:version_no).last
+
+      expect(page.title).to eq('wiki_history_update_body')
+      expect(page.body).to eq('after')
+
+      expect(version).to have_attributes(
+        event_type: 'update',
+        title: 'wiki_history_update_body',
+        body: 'after',
+        reason: 'edit body',
+        created_by_user_id: user.id
+      )
+    end
+
+    it 'renames title and records wiki_version with new title' do
+      page = create_wiki_page(title: 'wiki_history_rename_before', body: 'before')
+      current_id = page.current_revision.id
+
+      expect {
+        put "/wiki/#{ page.id }",
+            params: {
+              title: 'wiki_history_rename_after',
+              body: 'after',
+              message: 'rename',
+              base_revision_id: current_id,
+            },
+            headers: auth_headers(user)
+      }
+          .to change(WikiRevision, :count).by(1)
+          .and change(WikiVersion, :count).by(1)
+
+      expect(response).to have_http_status(:ok)
+
+      page.reload
+      version = page.wiki_versions.order(:version_no).last
+
+      expect(page.title).to eq('wiki_history_rename_after')
+      expect(page.body).to eq('after')
+
+      expect(version).to have_attributes(
+        event_type: 'update',
+        title: 'wiki_history_rename_after',
+        body: 'after',
+        reason: 'rename',
+        created_by_user_id: user.id
+      )
+    end
+
+    it 'does not change title, body, revision, or version on stale base_revision_id' do
+      page = create_wiki_page(title: 'wiki_history_conflict_page', body: 'first')
+      stale_id = page.current_revision.id
+
+      Wiki::Commit.content!(
+          page:,
+          body: 'second',
+          created_user: user,
+          message: 'other edit',
+          base_revision_id: stale_id)
+
+      page.reload
+      current_title = page.title
+      current_body = page.body
+      revision_count = page.wiki_revisions.count
+      version_count = page.wiki_versions.count
+
+      put "/wiki/#{ page.id }",
+          params: {
+            title: 'wiki_history_conflict_renamed',
+            body: 'third',
+            message: 'stale edit',
+            base_revision_id: stale_id,
+          },
+          headers: auth_headers(user)
+
+      expect(response).to have_http_status(:conflict)
+
+      page.reload
+      expect(page.title).to eq(current_title)
+      expect(page.body).to eq(current_body)
+      expect(page.wiki_revisions.count).to eq(revision_count)
+      expect(page.wiki_versions.count).to eq(version_count)
+    end
+  end
+end

backend/spec/requests/wiki_restore_pending_spec.rb

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

backend/spec/requests/wiki_spec.rb

@@ -4,13 +4,19 @@ require 'securerandom'
 
 
 RSpec.describe 'Wiki API', type: :request do
+  def auth_headers(user)
+    { 'X-Transfer-Code' => user.inheritance_code }
+  end
+
   let!(:user) { create_member_user! }
 
   let!(:tn) { TagName.create!(name: 'spec_wiki_title') }
   let!(:page) do
-    WikiPage.create!(tag_name: tn, created_user: user, updated_user: user).tap do |p|
+    Wiki::Commit.create_content!(
-      Wiki::Commit.content!(page: p, body: 'init', created_user: user, message: 'init')
+        tag_name: tn,
-    end
+        body: 'init',
+        created_by_user: user,
+        message: 'init')
   end
 
   describe 'GET /wiki' do
@@ -37,6 +43,7 @@ RSpec.describe 'Wiki API', type: :request do
     context 'when wiki page exists' do
       it 'returns wiki page with title' do
         request
+
         expect(response).to have_http_status(:ok)
 
         expect(json).to include(
@@ -50,6 +57,7 @@ RSpec.describe 'Wiki API', type: :request do
 
       it 'returns 404' do
         request
+
         expect(response).to have_http_status(:not_found)
       end
     end
@@ -99,25 +107,34 @@ RSpec.describe 'Wiki API', type: :request do
         end
             .to change(WikiPage, :count).by(1)
             .and change(WikiRevision, :count).by(1)
+            .and change(WikiVersion, :count).by(1)
 
         expect(response).to have_http_status(:created)
 
         page_id = json.fetch('id')
         expect(json.fetch('title')).to eq('TestPage')
 
-        page = WikiPage.find(page_id)
+        created_page = WikiPage.find(page_id)
-        rev = page.current_revision
+        version = created_page.wiki_versions.order(:version_no).last
+
+        expect(version).to have_attributes(
+          version_no: 1,
+          event_type: 'create',
+          title: 'TestPage',
+          body: "a\nb\nc",
+          created_by_user_id: member.id
+        )
+
+        rev = created_page.current_revision
         expect(rev).to be_present
         expect(rev).to be_content
         expect(rev.message).to eq('init')
 
-        # body が復元できること
+        expect(created_page.body).to eq("a\nb\nc")
-        expect(page.body).to eq("a\nb\nc")
 
-        # 行数とリレーションの整合
         expect(rev.lines_count).to eq(3)
         expect(rev.wiki_revision_lines.order(:position).pluck(:position)).to eq([0, 1, 2])
-        expect(rev.wiki_lines.pluck(:body)).to match_array(%w[a b c])
+        expect(rev.wiki_lines.pluck(:body)).to match_array(['a', 'b', 'c'])
       end
 
       it 'reuses existing WikiLine rows by sha256' do
@@ -135,6 +152,41 @@ RSpec.describe 'Wiki API', type: :request do
         # "a" の WikiLine が増殖しない（1行のはず）
         expect(WikiLine.where(body: 'a').count).to eq(1)
       end
+
+      it 'deduplicates duplicated new lines before upsert' do
+        duplicated = 'duplicated_line_for_wiki_line_upsert_spec'
+
+        post endpoint,
+             params: { title: 'DuplicateNewLine', body: "#{ duplicated }\n#{ duplicated }" },
+             headers: auth_headers(member)
+
+        expect(response).to have_http_status(:created)
+
+        page = WikiPage.find(json.fetch('id'))
+        rev = page.current_revision
+
+        expect(rev.lines_count).to eq(2)
+        expect(WikiLine.where(body: duplicated).count).to eq(1)
+        expect(rev.wiki_revision_lines.count).to eq(2)
+        expect(rev.wiki_revision_lines.pluck(:wiki_line_id).uniq.size).to eq(1)
+      end
+
+      it 'normalises CRLF and strips trailing newlines' do
+        post endpoint,
+             params: { title: 'NormalisedBody', body: "a\r\nb\r\n\r\n", message: 'normalise' },
+             headers: auth_headers(member)
+
+        expect(response).to have_http_status(:created)
+
+        page = WikiPage.find(json.fetch('id'))
+        rev = page.current_revision
+        version = page.wiki_versions.order(:version_no).last
+
+        expect(page.body).to eq("a\nb")
+        expect(version.body).to eq("a\nb")
+        expect(rev.lines_count).to eq(2)
+        expect(rev.wiki_lines.order('wiki_revision_lines.position').map(&:body)).to eq(['a', 'b'])
+      end
     end
   end
 
@@ -146,17 +198,14 @@ RSpec.describe 'Wiki API', type: :request do
       { 'X-Transfer-Code' => user.inheritance_code }
     end
 
-    #let!(:page) { create(:wiki_page, title: 'TestPage') }
+    let!(:test_tag_name) { TagName.create!(name: 'TestPage') }
-    let!(:page) do
-      build(:wiki_page, title: 'TestPage').tap do |p|
-        puts p.errors.full_messages unless p.valid?
-        p.save!
-      end
-    end
 
-    before do
+    let!(:page) do
-      # 初期版を 1 つ作っておく（更新が“2版目”になるように）
+      Wiki::Commit.create_content!(
-      Wiki::Commit.content!(page: page, body: "a\nb", created_user: member, message: 'init')
+          tag_name: test_tag_name,
+          body: "a\nb",
+          created_by_user: member,
+          message: 'init')
     end
 
     context 'when not logged in' do
@@ -182,14 +231,6 @@ RSpec.describe 'Wiki API', type: :request do
             headers: auth_headers(member)
         expect(response).to have_http_status(:unprocessable_entity)
       end
-
-      it 'returns 422 when title mismatched (if you forbid rename here)' do
-        put "/wiki/#{page.id}",
-            params: { title: 'OtherTitle', body: 'x' },
-            headers: auth_headers(member)
-        # 君の controller 例だと title 変更は 422 にしてた
-        expect(response).to have_http_status(:unprocessable_entity)
-      end
     end
 
     context 'when success' do
@@ -200,7 +241,18 @@ RSpec.describe 'Wiki API', type: :request do
           put "/wiki/#{page.id}",
               params: { title: 'TestPage', body: "x\ny", message: 'edit', base_revision_id: current_id },
               headers: auth_headers(member)
-        end.to change(WikiRevision, :count).by(1)
+        end
+            .to change(WikiRevision, :count).by(1)
+            .and change(WikiVersion, :count).by(1)
+
+        version = page.wiki_versions.order(:version_no).last
+
+        expect(version).to have_attributes(
+          event_type: 'update',
+          title: 'TestPage',
+          body: "x\ny",
+          created_by_user_id: member.id
+        )
 
         expect(response).to have_http_status(:ok)
 
@@ -211,25 +263,60 @@ RSpec.describe 'Wiki API', type: :request do
         expect(page.body).to eq("x\ny")
         expect(rev.base_revision_id).to eq(current_id)
       end
+
+      it 'wiki body だけを変更しても tag version は作成しない' do
+        linked_tag_name = TagName.create!(name: 'wiki_body_only_tag')
+        linked_tag = Tag.create!(tag_name: linked_tag_name, category: :general)
+
+        TagVersionRecorder.record!(
+            tag: linked_tag,
+            event_type: :create,
+            created_by_user: member)
+
+        linked_page =
+            Wiki::Commit.create_content!(
+                tag_name: linked_tag_name,
+                body: 'before',
+                created_by_user: member,
+                message: 'init')
+
+        current_id = linked_page.current_revision.id
+        before_count = linked_tag.reload.tag_versions.count
+
+        expect {
+          put "/wiki/#{ linked_page.id }",
+              params: {
+                title: 'wiki_body_only_tag',
+                body: 'after',
+                message: 'edit',
+                base_revision_id: current_id,
+              },
+              headers: auth_headers(member)
+        }
+            .to change(WikiRevision, :count).by(1)
+            .and change(WikiVersion, :count).by(1)
+
+        expect(response).to have_http_status(:ok)
+        expect(linked_tag.reload.tag_versions.count).to eq(before_count)
+      end
     end
 
-    # TODO: コンフリクト未実装のため，実装したらコメント外す．
+    context 'when conflict' do
-    # context 'when conflict' do
+      it 'returns 409 when base_revision_id mismatches' do
-    #   it 'returns 409 when base_revision_id mismatches' do
+        # 先に別ユーザ（同じ member でもOK）が 1 回更新して先頭を進める
-    #     # 先に別ユーザ（同じ member でもOK）が 1 回更新して先頭を進める
+        Wiki::Commit.content!(page: page, body: "zzz", created_user: member, message: 'other edit')
-    #     Wiki::Commit.content!(page: page, body: "zzz", created_user: member, message: 'other edit')
+        page.reload
-    #     page.reload
 
-    #     stale_id = page.wiki_revisions.order(:id).first.id # わざと古い id
+        stale_id = page.wiki_revisions.order(:id).first.id # わざと古い id
-    #     put "/wiki/#{page.id}",
+        put "/wiki/#{page.id}",
-    #         params: { title: 'TestPage', body: 'x', base_revision_id: stale_id },
+            params: { title: 'TestPage', body: 'x', base_revision_id: stale_id },
-    #         headers: auth_headers(member)
+            headers: auth_headers(member)
 
-    #     expect(response).to have_http_status(:conflict)
+        expect(response).to have_http_status(:conflict)
-    #     json = JSON.parse(response.body)
+        json = JSON.parse(response.body)
-    #     expect(json['error']).to eq('conflict')
+        expect(json['error']).to eq('conflict')
-    #   end
+      end
-    # end
+    end
 
     context 'when page not found' do
       it 'returns 404' do
@@ -261,14 +348,17 @@ RSpec.describe 'Wiki API', type: :request do
 
   describe 'GET /wiki/search' do
     before do
-      # 追加で検索ヒット用
+      Wiki::Commit.create_content!(
-      TagName.create!(name: 'spec_wiki_title_2')
+          tag_name: TagName.create!(name: 'spec_wiki_title_2'),
-      WikiPage.create!(tag_name: TagName.find_by!(name: 'spec_wiki_title_2'),
+          body: 'search body 2',
-                       created_user: user, updated_user: user)
+          created_by_user: user,
+          message: 'init')
 
-      TagName.create!(name: 'unrelated_title')
+      Wiki::Commit.create_content!(
-      WikiPage.create!(tag_name: TagName.find_by!(name: 'unrelated_title'),
+          tag_name: TagName.create!(name: 'unrelated_title'),
-                       created_user: user, updated_user: user)
+          body: 'unrelated body',
+          created_by_user: user,
+          message: 'init')
     end
 
     it 'returns up to 20 pages filtered by title like' do
@@ -278,7 +368,9 @@ RSpec.describe 'Wiki API', type: :request do
       expect(json).to be_an(Array)
 
       titles = json.map { |p| p['title'] }
-      expect(titles).to include('spec_wiki_title', 'spec_wiki_title_2')
+
+      expect(titles).to include('spec_wiki_title')
+      expect(titles).to include('spec_wiki_title_2')
       expect(titles).not_to include('unrelated_title')
     end
 
@@ -329,7 +421,12 @@ RSpec.describe 'Wiki API', type: :request do
     it 'returns empty array when page has no revisions and filtered by id' do
       # 別ページを作って revision 無し
       tn2 = TagName.create!(name: 'spec_no_rev')
-      p2 = WikiPage.create!(tag_name: tn2, created_user: user, updated_user: user)
+      # 異常データ: revision 無し WikiPage を直接作る
+      p2 = WikiPage.create!(
+          tag_name: tn2,
+          body: 'init',
+          created_user: user,
+          updated_user: user)
 
       get "/wiki/changes?id=#{p2.id}"
       expect(response).to have_http_status(:ok)
@@ -398,29 +495,68 @@ RSpec.describe 'Wiki API', type: :request do
       expect(json['older_revision_id']).to eq(rev_a.id)
       expect(json['newer_revision_id']).to eq(page.current_revision.id)
     end
-
-    it 'returns 422 when "to" is redirect revision' do
-      # redirect revision を作る
-      tn2 = TagName.create!(name: 'redirect_target')
-      target = WikiPage.create!(tag_name: tn2, created_user: user, updated_user: user)
-
-      Wiki::Commit.redirect!(page: page, redirect_page: target, created_user: user, message: 'redir')
-      redirect_rev = page.current_revision
-      expect(redirect_rev).to be_redirect
-
-      get "/wiki/#{page.id}/diff?from=#{rev_a.id}&to=#{redirect_rev.id}"
-      expect(response).to have_http_status(:unprocessable_entity)
   end
 
-    it 'returns 422 when "from" is redirect revision' do
+  describe 'Wiki::Commit.redirect!' do
-      tn2 = TagName.create!(name: 'redirect_target2')
+    it 'raises because redirect revisions are deprecated' do
-      target = WikiPage.create!(tag_name: tn2, created_user: user, updated_user: user)
+      target_tag_name = TagName.create!(name: 'redirect_deprecated_target')
+      target =
+          Wiki::Commit.create_content!(
+              tag_name: target_tag_name,
+              body: 'target',
+              created_by_user: user,
+              message: 'init')
 
-      Wiki::Commit.redirect!(page: page, redirect_page: target, created_user: user, message: 'redir2')
+      expect {
-      redirect_rev = page.current_revision
+        Wiki::Commit.redirect!(
+          page: page,
+          redirect_page: target,
+          created_user: user,
+          message: 'redirect',
+          base_revision_id: page.current_revision.id
+        )
+      }.to raise_error(RuntimeError, '廃止しました．')
+    end
+  end
 
-      get "/wiki/#{page.id}/diff?from=#{redirect_rev.id}&to=#{rev_b.id}"
+  it 'wiki title を変更すると対応する tag の version を作成する' do
-      expect(response).to have_http_status(:unprocessable_entity)
+    linked_tag_name = TagName.create!(name: 'wiki_linked_tag_for_version')
-    end
+    linked_tag = Tag.create!(tag_name: linked_tag_name, category: :general)
+
+    linked_page =
+        Wiki::Commit.create_content!(
+            tag_name: linked_tag_name,
+            body: 'before',
+            created_by_user: user,
+            message: 'init')
+
+    current_id = linked_page.current_revision.id
+
+    expect {
+      put "/wiki/#{ linked_page.id }",
+          params: {
+            title: 'wiki_linked_tag_for_version_renamed',
+            body: 'after',
+            message: 'rename',
+            base_revision_id: current_id,
+          },
+          headers: auth_headers(user)
+    }
+        .to change(WikiRevision, :count).by(1)
+        .and change(WikiVersion, :count).by(1)
+        .and change { linked_tag.reload.tag_versions.count }.by(2)
+
+    expect(response).to have_http_status(:ok)
+
+    linked_tag.reload
+    expect(linked_tag.name).to eq('wiki_linked_tag_for_version_renamed')
+
+    versions = linked_tag.tag_versions.order(:version_no)
+
+    expect(versions.first.event_type).to eq('create')
+    expect(versions.first.name).to eq('wiki_linked_tag_for_version')
+
+    expect(versions.second.event_type).to eq('update')
+    expect(versions.second.name).to eq('wiki_linked_tag_for_version_renamed')
   end
 end

backend/spec/requests/wiki_title_collision_spec.rb

@@ -0,0 +1,62 @@
+require 'rails_helper'
+
+RSpec.describe 'Wiki title collision', type: :request do
+  let!(:user) { create_member_user! }
+
+  def auth_headers user
+    { 'X-Transfer-Code' => user.inheritance_code }
+  end
+
+  def create_wiki_page title:, body:
+    Wiki::Commit.create_content!(
+        tag_name: TagName.create!(name: title),
+        body:,
+        created_by_user: user,
+        message: 'init')
+  end
+
+  it 'returns 422 when renaming wiki title to existing title' do
+    source = create_wiki_page(title: 'wiki_collision_source', body: 'source body')
+    create_wiki_page(title: 'wiki_collision_target', body: 'target body')
+
+    source_revision_count = source.wiki_revisions.count
+    source_version_count = source.wiki_versions.count
+    old_title = source.title
+    old_body = source.body
+
+    put "/wiki/#{ source.id }",
+        params: {
+          title: 'wiki_collision_target',
+          body: 'new body',
+          message: 'rename collision',
+          base_revision_id: source.current_revision.id,
+        },
+        headers: auth_headers(user)
+
+    expect(response).to have_http_status(:unprocessable_entity)
+
+    source.reload
+
+    expect(source.title).to eq(old_title)
+    expect(source.body).to eq(old_body)
+    expect(source.wiki_revisions.count).to eq(source_revision_count)
+    expect(source.wiki_versions.count).to eq(source_version_count)
+  end
+
+  it 'returns 422 when creating wiki with existing title' do
+    create_wiki_page(title: 'wiki_collision_create', body: 'already exists')
+
+    expect {
+      post '/wiki',
+           params: {
+             title: 'wiki_collision_create',
+             body: 'new body',
+             message: 'duplicate create',
+           },
+           headers: auth_headers(user)
+    }
+        .not_to change(WikiPage, :count)
+
+    expect(response).to have_http_status(:unprocessable_entity)
+  end
+end

backend/spec/services/wiki/commit_integrity_spec.rb

@@ -0,0 +1,173 @@
+require 'digest'
+require 'rails_helper'
+
+RSpec.describe Wiki::Commit do
+  let(:user) { create_member_user! }
+
+  def create_page title:, body: 'initial body'
+    described_class.create_content!(
+        tag_name: TagName.create!(name: title),
+        body:,
+        created_by_user: user,
+        message: 'init')
+  end
+
+  describe '.create_content!' do
+    it 'creates page, revision, and version with normalised body' do
+      expect {
+        described_class.create_content!(
+            tag_name: TagName.create!(name: 'commit_integrity_create'),
+            body: "a\r\nb\r\n\r\n",
+            created_by_user: user,
+            message: 'init')
+      }
+          .to change(WikiPage, :count).by(1)
+          .and change(WikiRevision, :count).by(1)
+          .and change(WikiVersion, :count).by(1)
+
+      page = WikiPage.joins(:tag_name).find_by!(tag_names: { name: 'commit_integrity_create' })
+      revision = page.current_revision
+      version = page.wiki_versions.order(:version_no).last
+
+      expect(page.body).to eq("a\nb")
+      expect(revision.lines_count).to eq(2)
+      expect(version.body).to eq("a\nb")
+      expect(version.reason).to eq('init')
+    end
+
+    it 'rejects body that becomes blank after normalisation' do
+      tag_name = TagName.create!(name: 'commit_integrity_blank')
+
+      expect {
+        described_class.create_content!(
+            tag_name:,
+            body: "\r\n\r\n",
+            created_by_user: user,
+            message: 'blank')
+      }
+          .to raise_error(ActiveRecord::RecordInvalid)
+
+      expect(WikiPage.where(tag_name:)).not_to exist
+    end
+  end
+
+  describe '.content!' do
+    it 'updates page body, revision, and version' do
+      page = create_page(title: 'commit_integrity_update', body: 'before')
+      current_id = page.current_revision.id
+
+      expect {
+        described_class.content!(
+            page:,
+            body: 'after',
+            created_user: user,
+            message: 'edit',
+            base_revision_id: current_id)
+      }
+          .to change(WikiRevision, :count).by(1)
+          .and change(WikiVersion, :count).by(1)
+
+      page.reload
+      version = page.wiki_versions.order(:version_no).last
+
+      expect(page.body).to eq('after')
+      expect(version.body).to eq('after')
+      expect(version.reason).to eq('edit')
+    end
+
+    it 'does not record tag_version on body-only wiki update' do
+      tag_name = TagName.create!(name: 'commit_integrity_linked_tag')
+      tag = Tag.create!(tag_name:, category: :general)
+
+      page =
+          described_class.create_content!(
+              tag_name:,
+              body: 'before',
+              created_by_user: user,
+              message: 'init')
+
+      TagVersionRecorder.record!(
+          tag:,
+          event_type: :create,
+          created_by_user: user)
+
+      before_count = tag.reload.tag_versions.count
+
+      described_class.content!(
+          page:,
+          body: 'after',
+          created_user: user,
+          message: 'edit',
+          base_revision_id: page.current_revision.id)
+
+      expect(tag.reload.tag_versions.count).to eq(before_count)
+    end
+
+    it 'raises conflict and leaves page, revision, and version unchanged' do
+      page = create_page(title: 'commit_integrity_conflict', body: 'first')
+      stale_id = page.current_revision.id
+
+      described_class.content!(
+          page:,
+          body: 'second',
+          created_user: user,
+          message: 'second',
+          base_revision_id: stale_id)
+
+      page.reload
+      before_body = page.body
+      before_revision_count = page.wiki_revisions.count
+      before_version_count = page.wiki_versions.count
+
+      expect {
+        described_class.content!(
+            page:,
+            body: 'third',
+            created_user: user,
+            message: 'stale',
+            base_revision_id: stale_id)
+      }
+          .to raise_error(Wiki::Commit::Conflict)
+
+      page.reload
+      expect(page.body).to eq(before_body)
+      expect(page.wiki_revisions.count).to eq(before_revision_count)
+      expect(page.wiki_versions.count).to eq(before_version_count)
+    end
+
+    it 'deduplicates duplicated missing wiki lines' do
+      page = create_page(title: 'commit_integrity_dedup', body: 'before')
+      duplicated = 'commit_integrity_duplicate_line'
+
+      described_class.content!(
+          page:,
+          body: "#{ duplicated }\n#{ duplicated }",
+          created_user: user,
+          message: 'dedup',
+          base_revision_id: page.current_revision.id)
+
+      revision = page.reload.current_revision
+
+      expect(WikiLine.where(body: duplicated).count).to eq(1)
+      expect(revision.wiki_revision_lines.count).to eq(2)
+      expect(revision.wiki_revision_lines.pluck(:wiki_line_id).uniq.size).to eq(1)
+    end
+  end
+
+  describe '.redirect!' do
+    it 'raises because redirect revisions are deprecated' do
+      page = create_page(title: 'commit_integrity_redirect_source', body: 'source')
+      target = create_page(title: 'commit_integrity_redirect_target', body: 'target')
+
+      expect {
+        described_class.redirect!(
+            page:,
+            redirect_page: target,
+            created_user: user,
+            message: 'redirect',
+            base_revision_id: page.current_revision.id)
+      }
+          .to raise_error(RuntimeError, '廃止しました．')
+    end
+  end
+end

backend/spec/services/wiki/commit_spec.rb

@@ -0,0 +1,150 @@
+require 'rails_helper'
+
+RSpec.describe Wiki::Commit do
+  let(:user) { create_member_user! }
+
+  def create_page(title: 'commit_spec_page', body: 'initial body')
+    tag_name = TagName.create!(name: title)
+
+    Wiki::Commit.create_content!(
+        tag_name:,
+        body:,
+        created_by_user: user,
+        message: 'init')
+  end
+
+  describe '.content!' do
+    it 'stores normalised body in wiki_pages and wiki_versions' do
+      page = create_page(title: 'commit_normalised_page')
+
+      described_class.content!(
+        page:,
+        body: "a\r\nb\r\n\r\n",
+        created_user: user,
+        message: 'init'
+      )
+
+      page.reload
+      version = page.wiki_versions.order(:version_no).last
+
+      expect(page.body).to eq("a\nb")
+      expect(version.body).to eq("a\nb")
+      expect(page.current_revision.lines_count).to eq(2)
+    end
+
+    it 'deduplicates duplicated missing wiki lines before upsert' do
+      page = create_page(title: 'commit_duplicate_line_page')
+      duplicated = 'commit_duplicate_line'
+
+      described_class.content!(
+        page:,
+        body: "#{ duplicated }\n#{ duplicated }",
+        created_user: user,
+        message: 'init'
+      )
+
+      page.reload
+
+      expect(WikiLine.where(body: duplicated).count).to eq(1)
+      expect(page.current_revision.lines_count).to eq(2)
+      expect(page.current_revision.wiki_revision_lines.count).to eq(2)
+    end
+
+    it 'raises conflict when base_revision_id is stale' do
+      page = create_page(title: 'commit_conflict_page')
+
+      first = described_class.content!(
+        page:,
+        body: 'first',
+        created_user: user,
+        message: 'first'
+      )
+
+      described_class.content!(
+        page:,
+        body: 'second',
+        created_user: user,
+        message: 'second',
+        base_revision_id: first.id
+      )
+
+      expect {
+        described_class.content!(
+          page:,
+          body: 'third',
+          created_user: user,
+          message: 'third',
+          base_revision_id: first.id
+        )
+      }.to raise_error(Wiki::Commit::Conflict)
+    end
+
+    it 'does not record tag version when corresponding tag has no versions' do
+      tag_name = TagName.create!(name: 'commit_linked_tag_without_versions')
+      tag = Tag.create!(tag_name:, category: :general)
+
+      page =
+          described_class.create_content!(
+              tag_name:,
+              body: 'before',
+              created_by_user: user,
+              message: 'init')
+
+      expect(tag.reload.tag_versions.count).to eq(0)
+
+      current_revision_id = page.current_revision.id
+
+      expect {
+        described_class.content!(
+            page:,
+            body: 'after',
+            created_user: user,
+            message: 'edit',
+            base_revision_id: current_revision_id)
+      }.to change(WikiVersion, :count).by(1)
+
+      expect(tag.reload.tag_versions.count).to eq(0)
+    end
+
+    it 'does not record tag version when corresponding tag has no versions' do
+      tag_name = TagName.create!(name: 'commit_linked_tag_without_versions')
+      tag = Tag.create!(tag_name:, category: :general)
+
+      page =
+          described_class.create_content!(
+              tag_name:,
+              body: 'before',
+              created_by_user: user,
+              message: 'init')
+
+      current_revision_id = page.current_revision.id
+
+      expect {
+        described_class.content!(
+            page:,
+            body: 'after',
+            created_user: user,
+            message: 'edit',
+            base_revision_id: current_revision_id)
+      }.to change(WikiVersion, :count).by(1)
+
+      expect(tag.reload.tag_versions.count).to eq(0)
+    end
+  end
+
+  describe '.redirect!' do
+    it 'raises because redirect revisions are deprecated' do
+      page = create_page(title: 'commit_redirect_source')
+      target = create_page(title: 'commit_redirect_target')
+
+      expect {
+        described_class.redirect!(
+          page:,
+          redirect_page: target,
+          created_user: user,
+          message: 'redirect'
+        )
+      }.to raise_error(RuntimeError, '廃止しました．')
+    end
+  end
+end

backend/spec/services/wiki_version_recorder_spec.rb

@@ -0,0 +1,99 @@
+require 'rails_helper'
+
+RSpec.describe WikiVersionRecorder do
+  let(:user) { create_member_user! }
+
+  def create_page title:, body: 'body'
+    Wiki::Commit.create_content!(
+        tag_name: TagName.create!(name: title),
+        body:,
+        created_by_user: user,
+        message: 'init')
+  end
+
+  describe '.record!' do
+    it 'records title, body, reason, user, and version number' do
+      page = create_page(title: 'wiki_version_recorder_basic', body: 'body')
+
+      expect {
+        described_class.record!(
+            page:,
+            event_type: :update,
+            reason: 'manual reason',
+            created_by_user: user)
+      }
+          .to change { page.reload.wiki_versions.count }.by(1)
+
+      version = page.wiki_versions.order(:version_no).last
+
+      expect(version).to have_attributes(
+        version_no: 2,
+        event_type: 'update',
+        title: 'wiki_version_recorder_basic',
+        body: 'body',
+        reason: 'manual reason',
+        created_by_user_id: user.id
+      )
+    end
+
+    it 'does not create duplicated update version for identical snapshot' do
+      page = create_page(title: 'wiki_version_recorder_duplicate', body: 'body')
+
+      described_class.record!(
+          page:,
+          event_type: :update,
+          reason: nil,
+          created_by_user: user)
+
+      before_count = page.reload.wiki_versions.count
+
+      described_class.record!(
+          page:,
+          event_type: :update,
+          reason: nil,
+          created_by_user: user)
+
+      expect(page.reload.wiki_versions.count).to eq(before_count)
+    end
+
+    it 'creates update version when title changes' do
+      page = create_page(title: 'wiki_version_recorder_title_before', body: 'body')
+      page.tag_name.update!(name: 'wiki_version_recorder_title_after')
+
+      expect {
+        described_class.record!(
+            page:,
+            event_type: :update,
+            reason: 'rename',
+            created_by_user: user)
+      }
+          .to change { page.reload.wiki_versions.count }.by(1)
+
+      version = page.wiki_versions.order(:version_no).last
+
+      expect(version.title).to eq('wiki_version_recorder_title_after')
+      expect(version.body).to eq('body')
+      expect(version.reason).to eq('rename')
+    end
+
+    it 'creates update version when body changes' do
+      page = create_page(title: 'wiki_version_recorder_body', body: 'before')
+      page.update!(body: 'after')
+
+      expect {
+        described_class.record!(
+            page:,
+            event_type: :update,
+            reason: 'body',
+            created_by_user: user)
+      }
+          .to change { page.reload.wiki_versions.count }.by(1)
+
+      version = page.wiki_versions.order(:version_no).last
+
+      expect(version.title).to eq('wiki_version_recorder_body')
+      expect(version.body).to eq('after')
+      expect(version.reason).to eq('body')
+    end
+  end
+end

backend/spec/services/youtube/api_client_spec.rb

@@ -0,0 +1,130 @@
+require 'rails_helper'
+
+RSpec.describe Youtube::ApiClient do
+  let(:api_key) { 'test-api-key' }
+  let(:client) { described_class.new(api_key:) }
+
+  describe '#search_videos' do
+    it 'calls YouTube search API with expected params' do
+      published_after = Time.zone.parse('2026-05-01 00:00:00')
+      published_before = Time.zone.parse('2026-05-02 00:00:00')
+
+      expect(client).to receive(:get_json).with(
+        '/search',
+        {
+          part: 'snippet',
+          type: 'video',
+          q: 'ぼざろクリーチャー',
+          order: 'date',
+          maxResults: 50,
+          regionCode: 'JP',
+          relevanceLanguage: 'ja',
+          publishedAfter: published_after.iso8601,
+          publishedBefore: published_before.iso8601,
+          pageToken: 'NEXT'
+        }
+      ).and_return({ 'items' => [] })
+
+      client.search_videos(
+        q: 'ぼざろクリーチャー',
+        published_after:,
+        published_before:,
+        page_token: 'NEXT'
+      )
+    end
+
+    it 'omits nil optional params' do
+      expect(client).to receive(:get_json).with(
+        '/search',
+        hash_excluding(:publishedAfter, :publishedBefore, :pageToken)
+      ).and_return({ 'items' => [] })
+
+      client.search_videos(q: 'ぼざろクリーチャー')
+    end
+  end
+
+  describe '#videos' do
+    it 'returns empty items when ids are empty' do
+      expect(client).not_to receive(:get_json)
+
+      expect(client.videos([])).to eq({ 'items' => [] })
+    end
+
+    it 'calls videos API with comma separated ids' do
+      expect(client).to receive(:get_json).with(
+        '/videos',
+        {
+          part: 'snippet,status,contentDetails',
+          id: 'video-1,video-2'
+        }
+      ).and_return({ 'items' => [] })
+
+      client.videos(['video-1', 'video-2'])
+    end
+  end
+
+  describe '#playlist_items' do
+    it 'calls playlistItems API with page token' do
+      expect(client).to receive(:get_json).with(
+        '/playlistItems',
+        {
+          part: 'snippet,contentDetails,status',
+          playlistId: 'PL123',
+          maxResults: 50,
+          pageToken: 'NEXT'
+        }
+      ).and_return({ 'items' => [] })
+
+      client.playlist_items(playlist_id: 'PL123', page_token: 'NEXT')
+    end
+
+    it 'omits page token when nil' do
+      expect(client).to receive(:get_json).with(
+        '/playlistItems',
+        {
+          part: 'snippet,contentDetails,status',
+          playlistId: 'PL123',
+          maxResults: 50
+        }
+      ).and_return({ 'items' => [] })
+
+      client.playlist_items(playlist_id: 'PL123')
+    end
+  end
+
+  describe '#channel' do
+    it 'calls channels API by id' do
+      expect(client).to receive(:get_json).with(
+        '/channels',
+        {
+          part: 'snippet,contentDetails',
+          id: 'UC123'
+        }
+      ).and_return({ 'items' => [] })
+
+      client.channel(id: 'UC123')
+    end
+
+    it 'calls channels API by handle' do
+      expect(client).to receive(:get_json).with(
+        '/channels',
+        {
+          part: 'snippet,contentDetails',
+          forHandle: '@some_handle'
+        }
+      ).and_return({ 'items' => [] })
+
+      client.channel(handle: '@some_handle')
+    end
+
+    it 'raises when neither id nor handle is given' do
+      expect { client.channel }.to raise_error(ArgumentError, 'id or handle is required')
+    end
+
+    it 'raises when both id and handle are given' do
+      expect do
+        client.channel(id: 'UC123', handle: '@some_handle')
+      end.to raise_error(ArgumentError, 'id or handle is required')
+    end
+  end
+end

backend/spec/services/youtube/sync_spec.rb

@@ -0,0 +1,310 @@
+require 'rails_helper'
+
+RSpec.describe Youtube::Sync do
+  let(:client) { instance_double(Youtube::ApiClient) }
+  let(:sync) { described_class.new(client:) }
+
+  before do
+    allow(PostVersionRecorder).to receive(:record!)
+    allow(PostVersionRecorder).to receive(:ensure_snapshot!)
+    allow(sync).to receive(:attach_thumbnail_if_needed!)
+  end
+
+  describe '#sync!' do
+    it 'returns without fetching video details when no video ids are discovered' do
+      allow(sync).to receive(:query_terms).and_return([])
+      allow(sync).to receive(:playlist_ids).and_return([])
+
+      expect(client).not_to receive(:videos)
+
+      sync.sync!
+    end
+
+    it 'discovers ids from search and all playlist pages' do
+      allow(sync).to receive(:query_terms).and_return(['ぼざろクリーチャー'])
+      allow(sync).to receive(:playlist_ids).and_return(['PL123'])
+      allow(sync).to receive(:sync_since).and_return(Time.zone.parse('2026-05-01 00:00:00'))
+
+      allow(client).to receive(:search_videos).with(
+        q: 'ぼざろクリーチャー',
+        published_after: Time.zone.parse('2026-05-01 00:00:00')
+      ).and_return({
+        'items' => [
+          {
+            'id' => {
+              'videoId' => 'search-video-1'
+            }
+          }
+        ]
+      })
+
+      allow(client).to receive(:playlist_items).with(
+        playlist_id: 'PL123',
+        page_token: nil
+      ).and_return({
+        'items' => [
+          {
+            'contentDetails' => {
+              'videoId' => 'playlist-video-1'
+            }
+          }
+        ],
+        'nextPageToken' => 'NEXT'
+      })
+
+      allow(client).to receive(:playlist_items).with(
+        playlist_id: 'PL123',
+        page_token: 'NEXT'
+      ).and_return({
+        'items' => [
+          {
+            'snippet' => {
+              'resourceId' => {
+                'videoId' => 'playlist-video-2'
+              }
+            }
+          }
+        ]
+      })
+
+      expect(client).to receive(:videos).with(
+        satisfy do |ids|
+          ids.sort == ['playlist-video-1', 'playlist-video-2', 'search-video-1']
+        end
+      ).and_return({ 'items' => [] })
+
+      sync.sync!
+    end
+
+    it 'creates a YouTube post with default tags and no_deerjikist when no deerjikist mapping exists' do
+      Tag.tagme
+      Tag.bot
+      Tag.youtube
+      Tag.video
+      Tag.no_deerjikist
+
+      allow(sync).to receive(:query_terms).and_return([])
+      allow(sync).to receive(:playlist_ids).and_return(['PL123'])
+
+      allow(client).to receive(:playlist_items).with(
+        playlist_id: 'PL123',
+        page_token: nil
+      ).and_return({
+        'items' => [
+          {
+            'contentDetails' => {
+              'videoId' => 'video-1'
+            }
+          }
+        ]
+      })
+
+      allow(client).to receive(:videos).with(['video-1']).and_return({
+        'items' => [
+          youtube_video_item(
+            id: 'video-1',
+            title: 'YouTube テスト動画',
+            channel_id: 'UC_NO_MAPPING'
+          )
+        ]
+      })
+
+      expect do
+        sync.sync!
+      end.to change(Post, :count).by(1)
+
+      post = Post.find_by!(url: 'https://www.youtube.com/watch?v=video-1')
+      tag_ids = post.tags.pluck(:id)
+
+      expect(post.title).to eq('YouTube テスト動画')
+      expect(post.uploaded_user_id).to be_nil
+      expect(post.original_created_from).to eq(Time.zone.parse('2026-05-01 12:34:00'))
+      expect(post.original_created_before).to eq(Time.zone.parse('2026-05-01 12:35:00'))
+
+      expect(tag_ids).to include(Tag.tagme.id)
+      expect(tag_ids).to include(Tag.bot.id)
+      expect(tag_ids).to include(Tag.youtube.id)
+      expect(tag_ids).to include(Tag.video.id)
+      expect(tag_ids).to include(Tag.no_deerjikist.id)
+
+      expect(PostVersionRecorder).to have_received(:record!).with(
+        post:,
+        event_type: :create,
+        created_by_user: nil
+      )
+    end
+
+    it 'uses deerjikist tag when channel id is mapped' do
+      Tag.tagme
+      Tag.bot
+      Tag.youtube
+      Tag.video
+      Tag.no_deerjikist
+
+      deerjikist_tag = Tag.find_or_create_by_tag_name!('テスト投稿者', category: :deerjikist)
+      Deerjikist.create!(
+        platform: 'youtube',
+        code: 'UC_MAPPED',
+        tag: deerjikist_tag
+      )
+
+      allow(sync).to receive(:query_terms).and_return([])
+      allow(sync).to receive(:playlist_ids).and_return(['PL123'])
+
+      allow(client).to receive(:playlist_items).with(
+        playlist_id: 'PL123',
+        page_token: nil
+      ).and_return({
+        'items' => [
+          {
+            'contentDetails' => {
+              'videoId' => 'video-1'
+            }
+          }
+        ]
+      })
+
+      allow(client).to receive(:videos).with(['video-1']).and_return({
+        'items' => [
+          youtube_video_item(
+            id: 'video-1',
+            title: 'YouTube テスト動画',
+            channel_id: 'UC_MAPPED'
+          )
+        ]
+      })
+
+      sync.sync!
+
+      post = Post.find_by!(url: 'https://www.youtube.com/watch?v=video-1')
+      tag_ids = post.tags.pluck(:id)
+
+      expect(tag_ids).to include(deerjikist_tag.id)
+      expect(tag_ids).not_to include(Tag.no_deerjikist.id)
+    end
+
+    it 'removes no_deerjikist when deerjikist mapping is added later' do
+      Tag.no_deerjikist
+
+      post = Post.create!(
+        title: '旧タイトル',
+        url: 'https://www.youtube.com/watch?v=video-1',
+        uploaded_user_id: nil,
+        original_created_from: Time.zone.parse('2026-05-01 00:00:00'),
+        original_created_before: Time.zone.parse('2026-05-01 00:01:00')
+      )
+      PostTag.create!(post:, tag: Tag.no_deerjikist)
+
+      deerjikist_tag = Tag.find_or_create_by_tag_name!('後から判明した投稿者', category: :deerjikist)
+      Deerjikist.create!(
+        platform: 'youtube',
+        code: 'UC_MAPPED_LATER',
+        tag: deerjikist_tag
+      )
+
+      allow(sync).to receive(:query_terms).and_return([])
+      allow(sync).to receive(:playlist_ids).and_return(['PL123'])
+
+      allow(client).to receive(:playlist_items).with(
+        playlist_id: 'PL123',
+        page_token: nil
+      ).and_return({
+        'items' => [
+          {
+            'contentDetails' => {
+              'videoId' => 'video-1'
+            }
+          }
+        ]
+      })
+
+      allow(client).to receive(:videos).with(['video-1']).and_return({
+        'items' => [
+          youtube_video_item(
+            id: 'video-1',
+            title: '新タイトル',
+            channel_id: 'UC_MAPPED_LATER'
+          )
+        ]
+      })
+
+      sync.sync!
+
+      post.reload
+      tag_ids = post.tags.pluck(:id)
+
+      expect(post.title).to eq('新タイトル')
+      expect(tag_ids).to include(deerjikist_tag.id)
+      expect(tag_ids).not_to include(Tag.no_deerjikist.id)
+
+      expect(PostVersionRecorder).to have_received(:ensure_snapshot!).with(
+        post,
+        created_by_user: nil
+      )
+      expect(PostVersionRecorder).to have_received(:record!).with(
+        post:,
+        event_type: :update,
+        created_by_user: nil
+      )
+    end
+
+    it 'matches existing youtu.be URL and does not create duplicate post' do
+      post = Post.create!(
+        title: '旧タイトル',
+        url: 'https://youtu.be/video-1',
+        uploaded_user_id: nil,
+        original_created_from: Time.zone.parse('2026-05-01 00:00:00'),
+        original_created_before: Time.zone.parse('2026-05-01 00:01:00')
+      )
+
+      allow(sync).to receive(:query_terms).and_return([])
+      allow(sync).to receive(:playlist_ids).and_return(['PL123'])
+
+      allow(client).to receive(:playlist_items).with(
+        playlist_id: 'PL123',
+        page_token: nil
+      ).and_return({
+        'items' => [
+          {
+            'contentDetails' => {
+              'videoId' => 'video-1'
+            }
+          }
+        ]
+      })
+
+      allow(client).to receive(:videos).with(['video-1']).and_return({
+        'items' => [
+          youtube_video_item(
+            id: 'video-1',
+            title: '新タイトル',
+            channel_id: 'UC_NO_MAPPING'
+          )
+        ]
+      })
+
+      expect do
+        sync.sync!
+      end.not_to change(Post, :count)
+
+      expect(post.reload.title).to eq('新タイトル')
+    end
+  end
+
+  def youtube_video_item(id:, title:, channel_id:)
+    {
+      'id' => id,
+      'snippet' => {
+        'title' => title,
+        'channelId' => channel_id,
+        'publishedAt' => '2026-05-01T12:34:56Z',
+        'thumbnails' => {
+          'high' => {
+            'url' => "https://img.youtube.com/#{id}.jpg"
+          }
+        },
+        'tags' => ['tag-a', 'tag-b']
+      }
+    }
+  end
+end

backend/spec/services/youtube/video_item_spec.rb

@@ -0,0 +1,93 @@
+require 'rails_helper'
+
+RSpec.describe Youtube::VideoItem do
+  describe '#initialize' do
+    it 'extracts fields from YouTube video API item' do
+      item = {
+        'id' => 'video-1',
+        'snippet' => {
+          'title' => 'テスト動画',
+          'channelId' => 'UC123',
+          'publishedAt' => '2026-05-01T12:34:56Z',
+          'tags' => ['tag-a', 'tag-b'],
+          'thumbnails' => {
+            'high' => {
+              'url' => 'https://img.youtube.com/high.jpg'
+            },
+            'medium' => {
+              'url' => 'https://img.youtube.com/medium.jpg'
+            }
+          }
+        }
+      }
+
+      video = described_class.new(item)
+
+      expect(video.id).to eq('video-1')
+      expect(video.title).to eq('テスト動画')
+      expect(video.channel_id).to eq('UC123')
+      expect(video.published_at).to eq(Time.iso8601('2026-05-01T12:34:56Z'))
+      expect(video.thumbnail_url).to eq('https://img.youtube.com/high.jpg')
+      expect(video.raw_tags).to eq(['tag-a', 'tag-b'])
+      expect(video.url).to eq('https://www.youtube.com/watch?v=video-1')
+    end
+
+    it 'uses highest priority thumbnail' do
+      item = {
+        'id' => 'video-1',
+        'snippet' => {
+          'title' => 'テスト動画',
+          'channelId' => 'UC123',
+          'publishedAt' => '2026-05-01T12:34:56Z',
+          'thumbnails' => {
+            'default' => {
+              'url' => 'https://img.youtube.com/default.jpg'
+            },
+            'standard' => {
+              'url' => 'https://img.youtube.com/standard.jpg'
+            },
+            'maxres' => {
+              'url' => 'https://img.youtube.com/maxres.jpg'
+            }
+          }
+        }
+      }
+
+      video = described_class.new(item)
+
+      expect(video.thumbnail_url).to eq('https://img.youtube.com/maxres.jpg')
+    end
+
+    it 'falls back to empty raw tags' do
+      item = {
+        'id' => 'video-1',
+        'snippet' => {
+          'title' => 'テスト動画',
+          'channelId' => 'UC123',
+          'publishedAt' => '2026-05-01T12:34:56Z',
+          'thumbnails' => {}
+        }
+      }
+
+      video = described_class.new(item)
+
+      expect(video.raw_tags).to eq([])
+    end
+
+    it 'returns nil thumbnail when no thumbnail exists' do
+      item = {
+        'id' => 'video-1',
+        'snippet' => {
+          'title' => 'テスト動画',
+          'channelId' => 'UC123',
+          'publishedAt' => '2026-05-01T12:34:56Z',
+          'thumbnails' => {}
+        }
+      }
+
+      video = described_class.new(item)
+
+      expect(video.thumbnail_url).to be_nil
+    end
+  end
+end

backend/spec/support/test_records.rb

@@ -2,14 +2,12 @@ module TestRecords
   def create_member_user!
     User.create!(name: 'spec user',
                  inheritance_code: SecureRandom.hex(16),
-                 role: 'member',
+                 role: 'member')
-                 banned: false)
   end
 
   def create_admin_user!
     User.create!(name: 'spec admin',
                  inheritance_code: SecureRandom.hex(16),
-                 role: 'admin',
+                 role: 'admin')
-                 banned: false)
   end
 end

backend/spec/tasks/nico_sync_spec.rb

@@ -104,7 +104,7 @@ RSpec.describe "nico:sync" do
       url: post.url,
       thumbnail_base: post.thumbnail_base,
       tags: snapshot_tags(post),
-      parent: post.parent,
+      parent_post_ids: post.snapshot_parent_post_ids.join(' '),
       original_created_from: post.original_created_from,
       original_created_before: post.original_created_before,
       created_at: Time.current,

backend/spec/tasks/post_sync_spec.rb

@@ -0,0 +1,25 @@
+require 'rails_helper'
+require 'rake'
+
+RSpec.describe 'post:sync' do
+  around do |example|
+    original_application = Rake.application
+    Rake.application = Rake::Application.new
+
+    Rake::Task.define_task(:environment)
+    load Rails.root.join('lib/tasks/sync_posts.rake')
+
+    example.run
+  ensure
+    Rake.application = original_application
+  end
+
+  it 'runs Youtube::Sync' do
+    sync = instance_double(Youtube::Sync)
+
+    expect(Youtube::Sync).to receive(:new).once.and_return(sync)
+    expect(sync).to receive(:sync!).once
+
+    Rake::Task['post:sync'].invoke
+  end
+end

frontend/src/App.tsx

@@ -10,6 +10,7 @@ import RouteBlockerOverlay from '@/components/RouteBlockerOverlay'
 import TopNav from '@/components/TopNav'
 import { Toaster } from '@/components/ui/toaster'
 import { apiPost, isApiError } from '@/lib/api'
+import DeerjikistDetailPage from '@/pages/deerjikists/DeerjikistDetailPage'
 import MaterialBasePage from '@/pages/materials/MaterialBasePage'
 import MaterialDetailPage from '@/pages/materials/MaterialDetailPage'
 import MaterialListPage from '@/pages/materials/MaterialListPage'
@@ -58,6 +59,7 @@ const RouteTransitionWrapper = ({ user, setUser }: {
 	  <Route path="/posts/changes" element={<PostHistoryPage/>}/>
 	  <Route path="/tags" element={<TagListPage/>}/>
 	  <Route path="/tags/:id" element={<TagDetailPage/>}/>
+	  <Route path="/tags/:id/deerjikists" element={<DeerjikistDetailPage/>}/>
 	  <Route path="/tags/nico" element={<NicoTagListPage user={user}/>}/>
 	  <Route path="/tags/changes" element={<TagHistoryPage/>}/>
 	  <Route path="/theatres/:id" element={<TheatreDetailPage/>}/>

frontend/src/components/PostEditForm.tsx

@@ -4,6 +4,7 @@ import PostFormTagsArea from '@/components/PostFormTagsArea'
 import PostOriginalCreatedTimeField from '@/components/PostOriginalCreatedTimeField'
 import Label from '@/components/common/Label'
 import { Button } from '@/components/ui/button'
+import { toast } from '@/components/ui/use-toast'
 import { apiPut } from '@/lib/api'
 
 import type { FC } from 'react'
@@ -35,20 +36,34 @@ export default (({ post, onSave }: Props) => {
       useState<string | null> (post.originalCreatedBefore)
   const [originalCreatedFrom, setOriginalCreatedFrom] =
       useState<string | null> (post.originalCreatedFrom)
-  const [title, setTitle] = useState (post.title)
+  const [parentPostIds, setParentPostIds] =
+      useState ((post.parentPosts ?? []).map (p => p.id).join (' '))
   const [tags, setTags] = useState<string> ('')
+  const [title, setTitle] = useState (post.title)
 
   const handleSubmit = async () => {
+    try
+    {
       const data = await apiPut<Post> (
 	  `/posts/${ post.id }`,
-	{ title, tags, original_created_from: originalCreatedFrom,
+	  { title, tags, parent_post_ids: parentPostIds,
+	    original_created_from: originalCreatedFrom,
 	    original_created_before: originalCreatedBefore },
 	  { headers: { 'Content-Type': 'multipart/form-data' } })
       onSave ({ ...post,
 		title:                  data.title,
 		tags:                   data.tags,
+		parentPosts:            data.parentPosts,
+		childPosts:             data.childPosts,
+		siblingPosts:           data.siblingPosts,
 		originalCreatedFrom:    data.originalCreatedFrom,
 		originalCreatedBefore:  data.originalCreatedBefore } as Post)
+      toast ({ description: '更新しました．' })
+    }
+    catch
+    {
+      toast ({ description: '更新はできなかったよ……' })
+    }
   }
 
   useEffect (() => {
@@ -66,6 +81,16 @@ export default (({ post, onSave }: Props) => {
 		 onChange={ev => setTitle (ev.target.value)}/>
 	</div>
 
+	{/* 親投稿 */}
+	<div>
+	  <Label>親投稿</Label>
+	  <input
+	      type="text"
+	      value={parentPostIds}
+	      onChange={e => setParentPostIds (e.target.value)}
+	      className="w-full border p-2 rounded"/>
+	</div>
+
 	{/* タグ */}
 	<PostFormTagsArea tags={tags} setTags={setTags}/>
 

frontend/src/components/PostList.tsx

@@ -3,6 +3,7 @@ import { useRef } from 'react'
 import { useLocation } from 'react-router-dom'
 
 import PrefetchLink from '@/components/PrefetchLink'
+import { cn } from '@/lib/utils'
 import { useSharedTransitionStore } from '@/stores/sharedTransitionStore'
 
 import type { FC, MouseEvent } from 'react'
@@ -39,8 +40,10 @@ export default (({ posts, onClick }: Props) => {
 		<motion.div
 		    ref={cardRef}
 		    layoutId={layoutId}
-		    className="w-full h-full overflow-hidden rounded-xl shadow
+		    className={cn ('w-full h-full overflow-hidden rounded-xl shadow',
-			       transform-gpu will-change-transform"
+				   'transform-gpu will-change-transform',
+				   (post.childPosts ?? []).length > 0 && 'outline-4 outline-green-500',
+				   (post.parentPosts ?? []).length > 0 && 'ring-4 ring-yellow-500')}
 		    whileHover={{ scale: 1.02 }}
 		    onLayoutAnimationStart={() => {
 		      if (!(cardRef.current))

frontend/src/components/TagLink.tsx

@@ -45,9 +45,9 @@ export default (({ tag,
       <>
 	{(linkFlg && withWiki) && (
 	    <span className="mr-1">
-	      {(tag.materialId != null || tag.hasWiki)
+	      {(tag.materialId != null || tag.hasWiki || tag.hasDeerjikists)
 	       ? (
-		  tag.materialId == null
+		  tag.materialId == null && !(tag.hasDeerjikists)
 		  ? (
 		      <PrefetchLink
 			  to={`/wiki/${ encodeURIComponent (tag.name) }`}
@@ -55,11 +55,19 @@ export default (({ tag,
 			?
 		      </PrefetchLink>)
 		  : (
+		      tag.materialId != null
+		      ? (
 			  <PrefetchLink
 			      to={`/materials/${ tag.materialId }`}
 			      className={linkClass}>
 			    ?
-		      </PrefetchLink>))
+			  </PrefetchLink>)
+		      : (
+			  <PrefetchLink
+			      to={`/tags/${ tag.id }/deerjikists`}
+			      className={linkClass}>
+			    ?
+			  </PrefetchLink>)))
 	       : (
 		  ['character', 'material'].includes (tag.category)
 		  ? (
@@ -70,6 +78,16 @@ export default (({ tag,
 			  title={`${ tag.name } 素材情報が存在しません．`}>
 			!
 		      </PrefetchLink>)
+		  : (
+		      tag.category === 'deerjikist'
+		      ? (
+			  <PrefetchLink
+			      to={`/tags/${ tag.id }/deerjikists`}
+			      className="animate-[wiki-blink_.25s_steps(2,end)_infinite]
+					 dark:animate-[wiki-blink-dark_.25s_steps(2,end)_infinite]"
+			      title={`${ tag.name } に関する情報が存在しません．`}>
+			    !
+			  </PrefetchLink>)
 		      : (
 			  <PrefetchLink
 			      to={`/wiki/${ encodeURIComponent (tag.name) }`}
@@ -77,7 +95,7 @@ export default (({ tag,
 					 dark:animate-[wiki-blink-dark_.25s_steps(2,end)_infinite]"
 			      title={`${ tag.name } Wiki が存在しません．`}>
 			    !
-		      </PrefetchLink>))}
+			  </PrefetchLink>)))}
 	    </span>)}
 	{nestLevel > 0 && (
 	    <span

frontend/src/consts.ts

@@ -1,4 +1,4 @@
-import type { Category } from 'types'
+import type { Category, Platform } from 'types'
 
 export const LIGHT_COLOUR_SHADE = 800
 export const DARK_COLOUR_SHADE = 300
@@ -31,6 +31,11 @@ export const FETCH_POSTS_ORDER_FIELDS = [
     'updated_at',
     ] as const
 
+export const PLATFORMS = ['nico', 'youtube'] as const
+
+export const PLATFORM_NAMES: Record<Platform, string> =
+    { nico: 'ニコニコ', youtube: 'YouTube' } as const
+
 export const TAG_COLOUR = {
     deerjikist: 'rose',
     meme:       'purple',

frontend/src/lib/queryKeys.ts

@@ -13,7 +13,8 @@ export const tagsKeys = {
     index:        (p: FetchTagsParams) => ['tags', 'index', p] as const,
     show:         (name: string) => ['tags', name] as const,
     changes:      (p: { id?: string; page: number; limit: number }) =>
-		  ['tags', 'changes', p] as const }
+		      ['tags', 'changes', p] as const,
+    deerjikists:  (id: string) => ['tags', 'deerjikists', id] as const }
 
 export const wikiKeys = {
     root:   ['wiki'] as const,

frontend/src/lib/tags.ts

@@ -1,6 +1,6 @@
 import { apiGet } from '@/lib/api'
 
-import type { FetchTagsParams, Tag, TagVersion } from '@/types'
+import type { Deerjikist, FetchTagsParams, Tag, TagVersion } from '@/types'
 
 
 export const fetchTags = async (
@@ -56,3 +56,9 @@ export const fetchTagChanges = async (
     versions: TagVersion[]
     count:    number }> =>
 	await apiGet ('/tags/versions', { params: { ...(id && { id }), page, limit } })
+
+
+export const fetchDeerjikistsByTag = async (
+    id: string,
+): Promise<{ tag: Tag; deerjikists: Deerjikist[]}> =>
+    await apiGet (`/tags/${ id }/deerjikists`)

frontend/src/pages/deerjikists/DeerjikistDetailPage.tsx

@@ -0,0 +1,155 @@
+import { useQuery, useQueryClient } from '@tanstack/react-query'
+import { useEffect, useState } from 'react'
+import { useParams } from 'react-router-dom'
+
+import TagLink from '@/components/TagLink'
+import Label from '@/components/common/Label'
+import PageTitle from '@/components/common/PageTitle'
+import MainArea from '@/components/layout/MainArea'
+import { toast } from '@/components/ui/use-toast'
+import { PLATFORM_NAMES, PLATFORMS } from '@/consts'
+import { apiPut } from '@/lib/api'
+import { tagsKeys } from '@/lib/queryKeys'
+import { fetchDeerjikistsByTag } from '@/lib/tags'
+import { cn } from '@/lib/utils'
+
+import type { FC, FormEvent } from 'react'
+
+import type { Deerjikist, Platform } from '@/types'
+
+
+export default (() => {
+  const { id } = useParams ()
+  const tagId = String (id ?? '')
+  const tagKey = tagsKeys.deerjikists (tagId)
+
+  const { data: qData, isLoading: loading } =
+      useQuery ({ queryKey: tagKey, queryFn: () => fetchDeerjikistsByTag (tagId) })
+  const tag = qData?.tag
+  const deerjikists = qData?.deerjikists ?? []
+
+  const [data, setData] =
+      useState<(Omit<Deerjikist, 'platform'> & { platform: Platform | null })[]> ([])
+  const [disabled, setDisabled] = useState (true)
+
+  const qc = useQueryClient ()
+
+  const handleSubmit = async (e: FormEvent) => {
+    e.preventDefault ()
+
+    try
+    {
+      setDisabled (true)
+
+      setData (await apiPut<Deerjikist[]> (`/tags/${ id }/deerjikists`, data))
+      qc.invalidateQueries ({ queryKey: tagsKeys.root })
+
+      toast ({ description: '更新しました．' })
+    }
+    catch
+    {
+      toast ({ title: '更新失敗', description: '入力内容を確認してください．' })
+    }
+    finally
+    {
+      setDisabled (false)
+    }
+  }
+
+  useEffect (() => {
+    if (!(tag))
+      {
+	setDisabled (true)
+	return
+      }
+
+    setData (deerjikists)
+    setDisabled (false)
+  }, [tag, deerjikists])
+
+  return (
+      <MainArea>
+	{(loading || !(tag)) ? 'Loading...' : (
+	    <div className="max-w-xl">
+	      <PageTitle>
+		<TagLink tag={tag} withWiki={false} withCount={false}/>
+	      </PageTitle>
+
+	      <form onSubmit={handleSubmit} className="my-4 space-y-2">
+		{data.map ((datum, i) => (
+		    <fieldset key={i} className="min-w-0 rounded-lg border border-gray-300
+						 dark:border-gray-700 p-4">
+		      <legend className="px-2 text-sm font-semibold text-gray-700
+					 dark:text-gray-300">
+			<button
+			    type="button"
+			    disabled={disabled}
+			    onClick={() => setData (prev => [...prev.slice (0, i),
+							     ...prev.slice (i + 1)])}>
+			  #{i + 1}
+			</button>
+		      </legend>
+
+		      {/* プラットフォーム */}
+		      <div>
+			<Label>プラットフォーム</Label>
+			<select
+			    className="w-full border p-2 rounded"
+			    disabled={disabled}
+			    value={datum.platform ?? ''}
+			    onChange={e => setData (prev => {
+			      const rtn = [...prev]
+			      rtn[i] = { ...rtn[i],
+					 platform: (e.target.value || null) as Platform | null }
+			      return rtn
+			    })}>
+			  <option value="">&nbsp;</option>
+			  {PLATFORMS.map (p => (
+			      <option key={p} value={p}>
+				{PLATFORM_NAMES[p]}
+			      </option>))}
+			</select>
+		      </div>
+
+		      {/* コード */}
+		      <div>
+			<Label>コード</Label>
+			<input
+			    type="text"
+			    disabled={disabled}
+			    className="w-full border p-2 rounded"
+			    value={datum.code}
+			    onChange={e => setData (prev => {
+			      const rtn = [...prev]
+			      rtn[i] = { ...rtn[i], code: e.target.value }
+			      return rtn
+			    })}/>
+		      </div>
+		    </fieldset>
+		))}
+
+		<div className="py-3">
+		  <button
+		      type="button"
+		      disabled={disabled}
+		      onClick={() => setData (prev => [...prev, { platform: null, code: '' }])}>
+		    +
+		  </button>
+		</div>
+
+		<div className="py-3">
+		  <button
+		      type="submit"
+		      disabled={disabled}
+		      className={cn ('px-4 py-2 rounded',
+				     (disabled
+				      ? 'text-gray-300 bg-gray-500'
+				      : 'text-white bg-blue-500'))}>
+		    更新
+		  </button>
+		</div>
+	      </form>
+	    </div>
+	)}
+      </MainArea>)
+}) satisfies FC

frontend/src/pages/posts/PostDetailPage.tsx

@@ -21,7 +21,7 @@ import ServiceUnavailable from '@/pages/ServiceUnavailable'
 
 import type { FC } from 'react'
 
-import type { NiconicoViewerHandle, User } from '@/types'
+import type { NiconicoViewerHandle, Post, User } from '@/types'
 
 type Props = { user: User | null }
 
@@ -108,6 +108,34 @@ export default (({ user }: Props) => {
 	  {post
 	   ? (
 	      <>
+		{(post.childPosts ?? []).length > 0 && (
+		    <div className="mb-4 bg-green-200 dark:bg-green-800 text-sm p-2 rounded-md">
+		      <p>この投稿には {post.childPosts!.length} 件の子投稿があります．</p>
+		      <PostList posts={[{ ...post, childPosts: [{ } as Post] },
+					...post.childPosts!.map (p => ({
+					    ...p, parentPosts: [{ } as Post] }))]}/>
+		    </div>
+		)}
+		{(post.parentPosts ?? []).map (pp => {
+		  const siblings = post.siblingPosts?.[String (pp.id) as `${ number }`]
+		  if (!(siblings))
+		    return
+
+		  return (
+		      <div
+			  key={pp.id}
+			  className="mb-4 bg-yellow-200 dark:bg-yellow-800 text-sm p-2 rounded-md">
+			<p>
+			  この投稿には 1 件の親投稿{
+			      siblings.length > 1
+			      && `と ${ siblings.length - 1 } 件の姉妹投稿`}があります．
+			</p>
+			<PostList posts={[{ ...pp, childPosts: [{ } as Post] },
+					  ...siblings.map (p => ({
+					      ...p, parentPosts: [{ } as Post] }))]}/>
+		      </div>)
+		})}
+
 		{(post.thumbnail || post.thumbnailBase) && (
 		    <motion.div
 			layoutId={`page-${ id }`}
@@ -146,7 +174,6 @@ export default (({ user }: Props) => {
 					       (prev: any) => newPost ?? prev)
 			      qc.invalidateQueries ({ queryKey: postsKeys.root })
 			      qc.invalidateQueries ({ queryKey: tagsKeys.root })
-			      toast ({ description: '更新しました．' })
 			    }}/>
 		      </Tab>)}
 		</TabGroup>

frontend/src/pages/posts/PostHistoryPage.tsx

@@ -95,6 +95,8 @@ export default (() => {
 		    <col className="w-96"/>
 		    {/* タグ */}
 		    <col className="w-[48rem]"/>
+		    {/* TODO: 親投稿 */}
+		    {/* <col className="w-[48rem]"/> */}
 		    {/* オリジナルの投稿日時 */}
 		    <col className="w-96"/>
 		    {/* 更新日時 */}
@@ -110,6 +112,8 @@ export default (() => {
 		      <th className="p-2 text-left">タイトル</th>
 		      <th className="p-2 text-left">URL</th>
 		      <th className="p-2 text-left">タグ</th>
+		      {/* TODO: 親投稿の履歴 */}
+		      {/* <th className="p-2 text-left">親投稿</th> */}
 		      <th className="p-2 text-left">オリジナルの投稿日時</th>
 		      <th className="p-2 text-left">更新日時</th>
 		      <th className="p-2"/>
@@ -180,6 +184,29 @@ export default (() => {
 					    {tag.name}
 					  </span>))))}
 			    </td>
+			    {/* TODO: 親投稿の履歴 */}
+			    {/* <td className="p-2">
+			      {change.parentPosts.map ((pp, i) => (
+				  pp.type === 'added'
+				  ? (
+				      <ins
+					  key={i}
+					  className="mr-2 text-green-600 dark:text-green-400">
+					{pp.title}
+				      </ins>)
+				  : (
+				      pp.type === 'removed'
+				      ? (
+					  <del
+					      key={i}
+					      className="mr-2 text-red-600 dark:text-red-400">
+					    {pp.title}
+					  </del>)
+				      : (
+					  <span key={i} className="mr-2">
+					    {pp.title}
+					  </span>))))}
+			    </td> */}
 			    <td className="p-2">
 			      {change.versionNo === 1
 			       ? originalCreatedAtString (change.originalCreatedFrom.current,
@@ -225,6 +252,11 @@ export default (() => {
 						  .map (t => t.name)
 						  .filter (t => t.slice (0, 5) !== 'nico:')
 						  .join (' '),
+					    parent_post_ids:
+						(change.parentPosts ?? [])
+						.filter (p => p.type !== 'removed')
+						.map (p => p.id)
+						.join (' '),
 					    original_created_from:
 						change.originalCreatedFrom.current,
 					    original_created_before:

frontend/src/pages/posts/PostNewPage.tsx

@@ -29,6 +29,7 @@ export default (({ user }: Props) => {
 
   const [originalCreatedBefore, setOriginalCreatedBefore] = useState<string | null> (null)
   const [originalCreatedFrom, setOriginalCreatedFrom] = useState<string | null> (null)
+  const [parentPostIds, setParentPostIds] = useState ('')
   const [tags, setTags] = useState ('')
   const [thumbnailAutoFlg, setThumbnailAutoFlg] = useState (true)
   const [thumbnailFile, setThumbnailFile] = useState<File | null> (null)
@@ -46,6 +47,7 @@ export default (({ user }: Props) => {
     formData.append ('title', title)
     formData.append ('url', url)
     formData.append ('tags', tags)
+    formData.append ('parent_post_ids', parentPostIds)
     if (thumbnailFile)
       formData.append ('thumbnail', thumbnailFile)
     if (originalCreatedFrom)
@@ -177,6 +179,16 @@ export default (({ user }: Props) => {
 		     className="mt-2 max-h-48 rounded border"/>)}
 	  </div>
 
+	  {/* 親投稿 */}
+	  <div>
+	    <Label>親投稿</Label>
+	    <input
+		type="text"
+		value={parentPostIds}
+		onChange={e => setParentPostIds (e.target.value)}
+		className="w-full border p-2 rounded"/>
+	  </div>
+
 	  {/* タグ */}
 	  <PostFormTagsArea tags={tags} setTags={setTags}/>
 

frontend/src/types.ts

@@ -1,5 +1,6 @@
 import { CATEGORIES,
 	 FETCH_POSTS_ORDER_FIELDS,
+	 PLATFORMS,
 	 USER_ROLES,
 	 ViewFlagBehavior } from '@/consts'
 
@@ -7,6 +8,8 @@ import type { ReactNode } from 'react'
 
 export type Category = typeof CATEGORIES[number]
 
+export type Deerjikist = { platform: Platform; code: string }
+
 export type FetchPostsOrder = `${ FetchPostsOrderField }:${ 'asc' | 'desc' }`
 
 export type FetchPostsOrderField = typeof FETCH_POSTS_ORDER_FIELDS[number]
@@ -114,6 +117,8 @@ export type NiconicoViewerHandle = {
     showComments: () => void
     hideComments: () => void }
 
+export type Platform = typeof PLATFORMS[number]
+
 export type Post = {
     id:                     number
     url:                    string
@@ -121,6 +126,9 @@ export type Post = {
     thumbnail:              string | null
     thumbnailBase:          string | null
     tags:                   Tag[]
+    parentPosts?:           Post[]
+    childPosts?:            Post[]
+    siblingPosts?:          Record<`${ number }`, Post[]>
     viewed:                 boolean
     related:                Post[]
     originalCreatedFrom:    string | null
@@ -144,7 +152,11 @@ export type PostVersion = {
     url:                    { current: string; prev: string | null }
     thumbnail:              { current: string | null; prev: string | null }
     thumbnailBase:          { current: string | null; prev: string | null }
-    tags:                   { name: string; type: 'context' | 'added' | 'removed' }[]
+    tags:                   { name: string
+			      type: 'context' | 'added' | 'removed' }[]
+    parentPosts:            { id: number
+			      title: string
+			      type: 'context' | 'added' | 'removed' }[]
     originalCreatedFrom:    { current: string | null; prev: string | null }
     originalCreatedBefore:  { current: string | null; prev: string | null }
     createdAt:              string
@@ -171,7 +183,8 @@ export type Tag = {
     createdAt:      string
     updatedAt:      string
     hasWiki:        boolean
-    materialId:     number
+    materialId:     number | null
+    hasDeerjikists: boolean
     children?:      Tag[]
     matchedAlias?:  string | null }