refactor bit flags code

lib/danbooru/has_bit_flags.rb

@@ -0,0 +1,33 @@
+module Danbooru
+  module HasBitFlags
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      # NOTE: the ordering of attributes has to be fixed#
+      # new attributes should be appended to the end.
+      def has_bit_flags(attributes, options = {})
+        field = options[:field] || :bit_flags
+
+        attributes.each.with_index do |attribute, i|
+          bit_flag = 1 << i
+
+          define_method(attribute) do
+            send(field) & bit_flag > 0
+          end
+
+          define_method("#{attribute}?") do
+            send(field) & bit_flag > 0
+          end
+
+          define_method("#{attribute}=") do |val|
+            if val.to_s =~ /t|1|y/
+              send("#{field}=", send(field) | bit_flag)
+            else
+              send("#{field}=", send(field) & ~bit_flag)
+            end
+          end
+        end
+      end
+    end
+  end
+end