reverted post version tag change for danbooru2

app/models/post_version.rb

@@ -17,12 +17,8 @@ class PostVersion < ActiveRecord::Base
     self.updater_ip_addr = CurrentUser.ip_addr
   end
   
-  def add_tag_array
-    @add_tag_array ||= add_tags.scan(/\S+/)
-  end
-  
-  def del_tag_array
-    @del_tag_array ||= del_tags.scan(/\S+/)
+  def tag_array
+    @tag_array ||= tags.scan(/\S+/)
   end
   
   def presenter
@@ -30,8 +26,45 @@ class PostVersion < ActiveRecord::Base
   end
   
   def reload
-    @add_tag_array = nil
-    @del_tag_array = nil
+    @tag_array = nil
     super
   end
+
+  def sequence_for_post
+    versions = PostVersion.where(:post_id => post_id).order("id desc").all
+    diffs = []
+    versions.each_index do |i|
+      if i < versions.size - 1
+        diffs << versions[i].diff(versions[i + 1])
+      end
+    end
+    return diffs
+  end
+  
+  def diff(version)
+    latest_tags = post.tag_array
+    new_tags = tag_array
+    new_tags << "rating:#{rating}" if rating.present?
+    new_tags << "parent:#{parent_id}" if parent_id.present?
+    new_tags << "source:#{source}" if source.present?
+    old_tags = version.present? ? version.tag_array : []
+    if version.present?
+      old_tags << "rating:#{version.rating}" if version.rating.present?
+      old_tags << "parent:#{version.parent_id}" if version.parent_id.present?
+      old_tags << "source:#{version.source}" if version.source.present?
+    end
+
+    return {
+      :added_tags => new_tags - old_tags,
+      :removed_tags => old_tags - new_tags,
+      :unchanged_tags => new_tags & old_tags,
+      :obsolete_added_tags => new_tags - latest_tags,
+      :obsolete_removed_tags => old_tags & latest_tags,
+    }
+  end
+  
+  def previous
+    PostVersion.where("post_id = ? and id < ?", post_id, id).order("id desc").first
+  end
+  
 end