pundit: convert forum topics / forum posts to pundit.

Fix it being possible for users to delete or undelete their own forum
posts and topics, even if they were deleted by a mod.

app/models/bulk_update_request.rb

@@ -63,7 +63,7 @@ class BulkUpdateRequest < ApplicationRecord
     def forum_updater
       @forum_updater ||= begin
         post = if forum_topic
-          forum_post || forum_topic.posts.first
+          forum_post || forum_topic.forum_posts.first
         else
           nil
         end
@@ -89,7 +89,7 @@ class BulkUpdateRequest < ApplicationRecord
     def create_forum_topic
       CurrentUser.as(user) do
         self.forum_topic = ForumTopic.create(title: title, category_id: 1, creator: user) unless forum_topic.present?
-        self.forum_post = forum_topic.posts.create(body: reason_with_link, creator: user) unless forum_post.present?
+        self.forum_post = forum_topic.forum_posts.create(body: reason_with_link, creator: user) unless forum_post.present?
         save
       end
     end

app/models/forum_post.rb

@@ -2,7 +2,7 @@ class ForumPost < ApplicationRecord
   attr_readonly :topic_id
   belongs_to :creator, class_name: "User"
   belongs_to_updater
-  belongs_to :topic, :class_name => "ForumTopic"
+  belongs_to :topic, class_name: "ForumTopic", inverse_of: :forum_posts
   has_many :dtext_links, as: :model, dependent: :destroy
   has_many :moderation_reports, as: :model
   has_many :votes, class_name: "ForumPostVote"
@@ -16,8 +16,6 @@ class ForumPost < ApplicationRecord
   after_update :update_topic_updated_at_on_update_for_original_posts
   after_destroy :update_topic_updated_at_on_destroy
   validates_presence_of :body
-  validate :validate_topic_is_unlocked
-  validate :topic_is_not_restricted, :on => :create
   after_save :delete_topic_if_original_post
   after_update(:if => ->(rec) {rec.updater_id != rec.creator_id}) do |rec|
     ModAction.log("#{CurrentUser.name} updated forum ##{rec.id}", :forum_post_update)
@@ -101,24 +99,8 @@ class ForumPost < ApplicationRecord
     end
   end
 
-  def validate_topic_is_unlocked
-    if topic.is_locked? && !updater.is_moderator?
-      errors[:topic] << "is locked"
-    end
-  end
-
-  def topic_is_not_restricted
-    if topic && !topic.visible?(creator)
-      errors[:topic] << "is restricted"
-    end
-  end
-
-  def editable_by?(user)
-    (creator_id == user.id || user.is_moderator?) && visible?(user)
-  end
-
   def visible?(user, show_deleted_posts = false)
-    user.is_moderator? || (topic.visible?(user) && (show_deleted_posts || !is_deleted?))
+    user.is_moderator? || (user.level >= topic.min_level && (show_deleted_posts || !is_deleted?))
   end
 
   def update_topic_updated_at_on_create

app/models/forum_topic.rb

@@ -13,11 +13,11 @@ class ForumTopic < ApplicationRecord
 
   belongs_to :creator, class_name: "User"
   belongs_to_updater
-  has_many :posts, -> {order("forum_posts.id asc")}, :class_name => "ForumPost", :foreign_key => "topic_id", :dependent => :destroy
+  has_many :forum_posts, foreign_key: "topic_id", dependent: :destroy, inverse_of: :topic
   has_many :forum_topic_visits
   has_one :forum_topic_visit_by_current_user, -> { where(user_id: CurrentUser.id) }, class_name: "ForumTopicVisit"
-  has_many :moderation_reports, through: :posts
-  has_one :original_post, -> {order("forum_posts.id asc")}, class_name: "ForumPost", foreign_key: "topic_id", inverse_of: :topic
+  has_many :moderation_reports, through: :forum_posts
+  has_one :original_post, -> { order(id: :asc) }, class_name: "ForumPost", foreign_key: "topic_id", inverse_of: :topic
   has_many :bulk_update_requests, :foreign_key => "forum_topic_id"
 
   validates_presence_of :title
@@ -147,14 +147,6 @@ class ForumTopic < ApplicationRecord
   include CategoryMethods
   include VisitMethods
 
-  def editable_by?(user)
-    (creator_id == user.id || user.is_moderator?) && visible?(user)
-  end
-
-  def visible?(user)
-    user.level >= min_level
-  end
-
   # XXX forum_topic_visit_by_current_user is a hack to reduce queries on the forum index.
   def is_read?
     return true if CurrentUser.is_anonymous?
@@ -179,7 +171,7 @@ class ForumTopic < ApplicationRecord
   end
 
   def page_for(post_id)
-    (posts.where("id < ?", post_id).count / Danbooru.config.posts_per_page.to_f).ceil
+    (forum_posts.where("id < ?", post_id).count / Danbooru.config.posts_per_page.to_f).ceil
   end
 
   def last_page