lib/woyo/world/attributes.rb in woyo-world-0.0.8 vs lib/woyo/world/attributes.rb in woyo-world-0.0.9

@@ -17,23 +17,60 @@
 
     def initialize
       @listeners = {}
     end
 
-    def add_attribute_listener attr, listener
-      @listeners[attr] = listener
+    def add_listener attr, listener
+      @listeners[attr] ||= []
+      @listeners[attr] << listener
     end
     
     def []= attr, value
       old_value = self[attr]
       super
-      if ( listener = @listeners[attr] ) && value != old_value
-        listener.notify attr, value
+      if value != old_value
+        @listeners[attr].each { |listener| listener.notify attr, value } if @listeners[attr]  # attribute listeners (groups, etc..)
+        @listeners[:*].each   { |listener| listener.notify attr, value } if @listeners[:*]    # wildcard listeners (trackers)
       end
     end
 
   end
-  
+
+  class ChangesHash < Hash
+
+    alias_method :names, :keys
+    alias_method :set, :[]=
+
+    def notify attr, value
+      self[attr] = value  
+    end
+
+  end
+
+  def changes
+    @changes ? @changes.merge!( dependent_changes ) : nil 
+  end
+
+  def dependent_changes
+    remaining_attrs = @attributes.names - @changes.names
+    dependent_attrs = remaining_attrs.select do |attr|
+      @attributes[attr].kind_of?( Hash ) && ! ( @attributes[attr].keys & @changes.names ).empty?
+    end
+    dependent_attrs.each_with_object({}) do |attr,hash|
+      hash[attr] = send attr
+    end
+  end
+
+  def track_changes
+    @changes = ChangesHash.new
+    @attributes ||= Woyo::Attributes::AttributesHash.new
+    @attributes.add_listener :*, @changes  # :* indicates listener for changes to all attributes
+  end
+
+  def clear_changes
+    @changes.clear
+  end
+
   def attribute *attrs, &block
     attributes *attrs, &block
   end
 
   def attributes *attrs, &block