Auto-add automatic tags whenever post is updated

Instead of being limited to when it's first uploaded.

app/models/post.rb

@@ -424,6 +424,7 @@ class Post < ActiveRecord::Base
       normalized_tags = TagAlias.to_aliased(normalized_tags)
       normalized_tags = TagImplication.with_descendants(normalized_tags)
       normalized_tags = %w(tagme) if normalized_tags.empty?
+      normalized_tags = add_automatic_tags(normalized_tags)
       normalized_tags.sort!
       set_tag_string(normalized_tags.uniq.sort.join(" "))
     end
@@ -434,6 +435,37 @@ class Post < ActiveRecord::Base
       return tags - negated_tags
     end
 
+    def add_automatic_tags(tags)
+      return tags if !Danbooru.config.enable_dimension_autotagging
+
+      tags -= %w(incredibly_absurdres absurdres highres lowres huge_filesize)
+
+      if image_width >= 10_000 || image_height >= 10_000
+        tags << "incredibly_absurdres"
+      end
+      if image_width >= 3200 || image_height >= 2400
+        tags << "absurdres"
+      end
+      if image_width >= 1600 || image_height >= 1200
+        tags << "highres"
+      end
+      if image_width <= 500 && image_height <= 500
+        tags << "lowres"
+      end
+
+      if file_size >= 10.megabytes
+        tags << "huge_filesize"
+      end
+
+      if image_width >= 1024 && image_width.to_f / image_height >= 4
+        tags << "wide_image"
+      elsif image_height >= 1024 && image_height.to_f / image_width >= 4
+        tags << "tag_image"
+      end
+
+      return tags
+    end
+
     def filter_metatags(tags)
       @pre_metatags, tags = tags.partition {|x| x =~ /\A(?:rating|parent|-parent):/i}
       @post_metatags, tags = tags.partition {|x| x =~ /\A(?:-pool|pool|newpool|fav|child):/i}

app/models/upload.rb

@@ -77,10 +77,8 @@ class Upload < ActiveRecord::Base
         validate_md5_uniqueness
         validate_md5_confirmation
         calculate_file_size(file_path)
-        add_file_size_tags!(file_path)
         if has_dimensions?
           calculate_dimensions(file_path)
-          add_dimension_tags!
         end
         generate_resizes(file_path)
         move_file
@@ -174,31 +172,6 @@ class Upload < ActiveRecord::Base
       end
     end
 
-    def add_dimension_tags!
-      return if !Danbooru.config.enable_dimension_autotagging
-
-      %w(incredibly_absurdres absurdres highres lowres).each do |tag|
-        escaped_tag = Regexp.escape(tag) 
-        self.tag_string = tag_string.gsub(/(?:\A| )#{escaped_tag}(?:\Z| )/, " ").strip
-      end
-
-      if image_width >= 10_000 || image_height >= 10_000
-        self.tag_string = "#{tag_string} incredibly_absurdres".strip
-      elsif image_width >= 3200 || image_height >= 2400
-        self.tag_string = "#{tag_string} absurdres".strip
-      elsif image_width >= 1600 || image_height >= 1200
-        self.tag_string = "#{tag_string} highres".strip
-      elsif image_width <= 500 && image_height <= 500
-        self.tag_string = "#{tag_string} lowres".strip
-      end
-
-      if image_width >= 1024 && image_width.to_f / image_height >= 4
-        self.tag_string = "#{tag_string} wide_image".strip
-      elsif image_height >= 1024 && image_height.to_f / image_width >= 4
-        self.tag_string = "#{tag_string} tall_image".strip
-      end
-    end
-
     # Does this file have image dimensions?
     def has_dimensions?
       %w(jpg gif png swf).include?(file_ext)
@@ -406,12 +379,6 @@ class Upload < ActiveRecord::Base
   extend SearchMethods
   include ApiMethods
 
-  def add_file_size_tags!(file_path)
-    if file_size >= 10.megabytes
-      self.tag_string = "#{tag_string} huge_filesize".strip
-    end
-  end
-
   def uploader_name
     User.id_to_name(uploader_id)
   end