まとめ詳細: タグによる関連まとめを実装

app/controllers/matomes_controller.rb

@@ -20,10 +20,14 @@ def show
     # 関連まとめ
     @related_matomes = {}
     # 1. 同じキュレータ
+    # TODO: インスタンスメソッド化
     @related_matomes[:user] = Matome.related_by_user(@matome).limit(5)
     # 2. 同じクリップを含む
+    # TODO: インスタンスメソッド化
     @related_matomes[:clip] = Matome.related_by_clips(@matome).limit(5)
-    # TODO: 3. 同じタグを含む
+    # 3. 同じタグを含む
+    # TODO: SQLの最適化
+    @related_matomes[:tag] = @matome.related_by_tags.take(5)
 
     return if first_page?
 

app/models/matome.rb

@@ -42,4 +42,36 @@ def increment_view_count!(request = nil)
       )
     end
   end
+
+  def related_by_tags
+    (related_by_clip_tags + related_by_matome_tags).uniq
+  end
+
+  def related_by_clip_tags
+    self.class.
+      joins(:clips).
+      merge(related_clips_by_tags).
+      where.not('matomes.id' => self.id).
+      group('matomes.id')
+  end
+
+  def related_by_matome_tags
+    self.class.
+      joins(:tags).
+      merge(related_tags).
+      where.not('matomes.id' => self.id).
+      group('matomes.id')
+  end
+
+  private
+
+  def related_tags
+    related_tag_ids_to_matome = self.tags.uniques.pluck(:name)
+    related_tag_ids_to_clips = Tag.uniques.for(self.clips).pluck(:name)
+    Tag.uniques.where(name: (related_tag_ids_to_matome + related_tag_ids_to_clips).uniq)
+  end
+
+  def related_clips_by_tags
+    Clip.joins(:tags).merge(related_tags)
+  end
 end

app/models/tag.rb

@@ -4,8 +4,8 @@ class Tag < ActiveRecord::Base
   belongs_to :user
 
   scope :uniques, group(:name)
-  scope :by, lambda {|user| where(user_id: user.is_a?(User) ? user.id : user) if user }
-  scope :for, lambda {|tagged| where(tagged_id: tagged.id, tagged_type: tagged.class.name) }
+  scope :by, lambda {|user| where(user_id: user) }
+  scope :for, lambda {|tagged| where(tagged_id: tagged, tagged_type: tagged.is_a?(Array) ? tagged.first.class.name : tagged.class.name) }
   scope :hot, lambda {|limit| uniques.select("name, COUNT(name) AS name_count").reorder('name_count desc').limit(limit) }
 
   validates :tagged_id, :presence => true

app/views/matomes/show.html.slim

@@ -71,10 +71,10 @@
     - else
       = link_to "続きを見る (#{left_clips_count}件)", new_user_registration_path, remote: true
 
-  - if @related_matomes[:clip].present?
+  - if @related_matomes[:clip].present? || @related_matomes[:tag].present?
     .related
       h2 関連まとめ
-      == render partial: 'base/matomes', locals: { matomes: @related_matomes[:clip] }
+      == render partial: 'base/matomes', locals: { matomes: (@related_matomes[:clip] + @related_matomes[:tag]).uniq }
 
   - if @related_matomes[:user].present?
     .related