lib/referehencible.rb in referehencible-0.1.1 vs lib/referehencible.rb in referehencible-0.2.0

@@ -1,34 +1,46 @@
 require 'referehencible/version'
 require 'securerandom'
 
 module Referehencible
-  def self.included(base)
-    base.class_eval do
-      ###
-      # Validations
-      #
-      validates       :guid,
-                        presence:         true,
-                        uniqueness:       true,
-                        format:           {
-                          with:             /[a-f0-9]{32}/ },
-                        length:           {
-                          is:               32 }
+  module ClassMethods
+    def referenced_by(*referenced_attributes)
+      referenced_attributes.each do |reference_attribute|
+        validates       reference_attribute,
+                          presence:         true,
+                          uniqueness:       true,
+                          format:           {
+                            with:             /[a-f0-9]{32}/ },
+                          length:           {
+                            is:               32 }
 
-      ###
-      # Hooks
-      #
-      before_create   :generate_guid
+        define_method(reference_attribute) do
+          generate_guid(reference_attribute)
+        end
 
-      ###
-      # ActiveRecord Overrides
-      #
-      def guid; generate_guid; end
+        define_singleton_method("by_#{reference_attribute}") do |guid_to_find|
+          where(:"#{reference_attribute}" => guid_to_find).
+          first ||
+          unknown_reference_object
+        end
+
+        after_initialize lambda { generate_guid reference_attribute }
+      end
+
+      private
+
+      define_method(:generate_guid) do |reference_attribute|
+        read_attribute(reference_attribute) || write_attribute(reference_attribute, SecureRandom.hex(16))
+      end
+
+      define_singleton_method(:unknown_reference_object) do
+        return new unless respond_to?(:as_null_object)
+
+        as_null_object
+      end
     end
   end
 
-private
-  def generate_guid
-    read_attribute(:guid) || write_attribute('guid', SecureRandom.hex(16))
+  def self.included(base)
+    base.extend ClassMethods
   end
 end