#77

backend/app/controllers/nico_tags_controller.rb

@@ -0,0 +1,24 @@
+class NicoTagsController < ApplicationController
+  def index
+    limit = (params[:limit] || 20).to_i
+    cursor = params[:cursor].presence
+
+    q = Tag.nico_tags.includes(:linked_tags)
+    q = q.where('tags.updated_at < ?', Time.iso8601(cursor)) if cursor
+
+    tags = q.limit(limit + 1)
+
+    next_cursor = nil
+    if tags.size > limit
+      next_cursor = tags.last.updated_at.iso8601(6)
+      tags = tags.first(limit)
+    end
+
+    render json: { tags: tags.map { |tag|
+      tag.as_json(include: :linked_tags)
+    }, next_cursor: }
+  end
+
+  def upload
+  end
+end

backend/app/controllers/posts_controller.rb

@@ -6,14 +6,10 @@ class PostsController < ApplicationController
   # GET /posts
   def index
     limit = (params[:limit] || 20).to_i
-    cursor = params[:cursor]
+    cursor = params[:cursor].presence
 
     q = filtered_posts.order(created_at: :desc)
-
-    next_cursor = nil
-    if cursor.present?
-      q = q.where('posts.created_at < ?', Time.iso8601(cursor))
-    end
+    q = q.where('posts.created_at < ?', Time.iso8601(cursor)) if cursor
 
     posts = q.limit(limit + 1)
 

backend/app/models/nico_tag_relation.rb

@@ -1,6 +1,6 @@
 class NicoTagRelation < ApplicationRecord
-  belongs_to :nico_tag, class_name: 'Tag', foreign_key: 'nico_tag_id'
-  belongs_to :tag, class_name: 'Tag', foreign_key: 'tag_id'
+  belongs_to :nico_tag, class_name: 'Tag'
+  belongs_to :tag, class_name: 'Tag'
 
   validates :nico_tag_id, presence: true
   validates :tag_id, presence: true
@@ -14,4 +14,10 @@ class NicoTagRelation < ApplicationRecord
       errors.add :nico_tag_id, 'タグのカテゴリがニコニコである必要があります．'
     end
   end
+
+  def tag_mustnt_be_nico
+    if tag && tag.category == 'nico'
+      errors.add :tag_id, '連携先タグのカテゴリはニコニコであってはなりません．'
+    end
+  end
 end

backend/app/models/tag.rb

@@ -2,7 +2,14 @@ class Tag < ApplicationRecord
   has_many :post_tags, dependent: :destroy
   has_many :posts, through: :post_tags
   has_many :tag_aliases, dependent: :destroy
-  has_many :wiki_pages, dependent: :nullify
+
+  has_many :nico_tag_relations, foreign_key: :nico_tag_id, dependent: :destroy
+  has_many :linked_tags, through: :nico_tag_relations, source: :tag
+
+  has_many :reversed_nico_tag_relations, class_name: 'NicoTagRelation',
+                                         foreign_key: :tag_id,
+                                         dependent: :destroy
+  has_many :linked_nico_tags, through: :reversed_nico_tag_relations, source: :nico_tag
 
   enum :category, { deerjikist:  'deerjikist',
                     meme:        'meme',
@@ -17,7 +24,7 @@ class Tag < ApplicationRecord
 
   validate :nico_tag_name_must_start_with_nico
 
-  scope :nico_tags, -> { where category: :nico }
+  scope :nico_tags, -> { where(category: :nico) }
 
   def self.tagme
     @tagme ||= Tag.find_or_initialize_by(name: 'タグ希望') do |tag|
@@ -34,7 +41,8 @@ class Tag < ApplicationRecord
   private
 
   def nico_tag_name_must_start_with_nico
-    if category == 'nico' && name&.[](0, 5) != 'nico:'
+    if ((category == 'nico' && name&.[](0, 5) != 'nico:') || 
+        (category != 'nico' && name&.[](0, 5) == 'nico:'))
       errors.add :name, 'ニコニコ・タグの命名規則に反してゐます．'
     end
   end