feat: 投稿とタグのリレーション・テーブルについて論理削除と履歴を追加（#84） (#148)

#84 マイグレ修正

Merge remote-tracking branch 'origin/main' into feature/084

#84 構文エラー修正

#84

#84

Co-authored-by: miteruzo <miteruzo@naver.com>
Reviewed-on: #148

backend/app/models/post.rb

@@ -1,11 +1,13 @@
-require 'mini_magick'
-
-
 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
-  has_many :tags, through: :post_tags
+
+  has_many :post_tags, dependent: :destroy, inverse_of: :post
+  has_many :active_post_tags, -> { kept }, class_name: 'PostTag', inverse_of: :post
+  has_many :post_tags_with_discarded, -> { with_discarded }, class_name: 'PostTag'
+  has_many :tags, through: :active_post_tags
   has_many :user_post_views, dependent: :destroy
   has_many :post_similarities_as_post,
            class_name: 'PostSimilarity',

backend/app/models/post_tag.rb

@@ -1,7 +1,25 @@
 class PostTag < ApplicationRecord
+  include Discard::Model
+
   belongs_to :post
   belongs_to :tag, counter_cache: :post_count
+  belongs_to :created_user, class_name: 'User', optional: true
+  belongs_to :deleted_user, class_name: 'User', optional: true
 
   validates :post_id, presence: true
   validates :tag_id, presence: true
+  validates :post_id, uniqueness: {
+      scope: :tag_id,
+      conditions: -> { where(discarded_at: nil) } }
+
+  def discard_by! deleted_user
+    return self if discarded?
+
+    transaction do
+      update!(discarded_at: Time.current, deleted_user:)
+      Tag.where(id: tag_id).update_all('post_count = GREATEST(post_count - 1, 0)')
+    end
+
+    self
+  end
 end

backend/app/models/tag.rb

@@ -1,6 +1,8 @@
 class Tag < ApplicationRecord
-  has_many :post_tags, dependent: :destroy
-  has_many :posts, through: :post_tags
+  has_many :post_tags, dependent: :delete_all, inverse_of: :tag
+  has_many :active_post_tags, -> { kept }, class_name: 'PostTag', inverse_of: :tag
+  has_many :post_tags_with_discarded, -> { with_discarded }, class_name: 'PostTag'
+  has_many :posts, through: :active_post_tags
   has_many :tag_aliases, dependent: :destroy
 
   has_many :nico_tag_relations, foreign_key: :nico_tag_id, dependent: :destroy
@@ -43,13 +45,13 @@ class Tag < ApplicationRecord
       'meta:' => 'meta' }.freeze
 
   def self.tagme
-    @tagme ||= Tag.find_or_initialize_by(name: 'タグ希望') do |tag|
+    @tagme ||= Tag.find_or_create_by!(name: 'タグ希望') do |tag|
       tag.category = 'meta'
     end
   end
 
   def self.bot
-    @bot ||= Tag.find_or_initialize_by(name: 'bot操作') do |tag|
+    @bot ||= Tag.find_or_create_by!(name: 'bot操作') do |tag|
       tag.category = 'meta'
     end
   end