models: factor out concerns to app/logical/concerns.

app/logical/concerns/has_bit_flags.rb

@@ -0,0 +1,36 @@
+module HasBitFlags
+  extend ActiveSupport::Concern
+
+  # NOTE: the ordering of attributes has to be fixed#
+  # new attributes should be appended to the end.
+  def has_bit_flags(attributes, 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
+
+    # bit_prefs_match
+    define_singleton_method("#{field}_match") do |flag, value|
+      value = value ? 1 : 0
+      bits = attributes.length
+      bit_index = bits - attributes.index(flag.to_s) - 1
+
+      where(sanitize_sql(["get_bit(#{field}::bit(?), ?) = ?", bits, bit_index, value]))
+    end
+  end
+end