From e07e0b92e2d2020093f9b9b382b5e654db22ca28 Mon Sep 17 00:00:00 2001
From: Aaron Qian <aq1018@gmail.com>
Date: Tue, 20 Dec 2011 00:18:13 -0800
Subject: [PATCH] fixed real time aggregation

---
 .../aggregation_strategy/real_time.rb         | 56 ++++++++++---------
 1 file changed, 31 insertions(+), 25 deletions(-)

diff --git a/lib/mongoid/taggable_with_context/aggregation_strategy/real_time.rb b/lib/mongoid/taggable_with_context/aggregation_strategy/real_time.rb
index 80b7ba9..885e0f4 100644
--- a/lib/mongoid/taggable_with_context/aggregation_strategy/real_time.rb
+++ b/lib/mongoid/taggable_with_context/aggregation_strategy/real_time.rb
@@ -3,8 +3,8 @@ module RealTime
     extend ActiveSupport::Concern
     
     included do
-      set_callback :save,     :after, :update_tags_aggregation, :if => :tags_changed?
-      set_callback :destroy,  :after, :update_tags_aggregation
+      set_callback :save,     :after, :update_tags_aggregations_on_save
+      set_callback :destroy,  :after, :update_tags_aggregations_on_destroy
     end
     
     module ClassMethods
@@ -27,34 +27,40 @@ def tags_with_weight_for(context, conditions={})
     end
     
     protected
+    
+    def update_tags_aggregation(context_array_field, old_tags=[], new_tags=[])
+      context = context_array_to_context_hash[context_array_field]
+      coll = self.class.db.collection(self.class.aggregation_collection_for(context))
 
-    def changed_tag_arrays
-      tag_array_attributes & changes.keys.map(&:to_sym)
+      old_tags ||= []
+      new_tags ||= []
+      unchanged_tags  = old_tags & new_tags
+      tags_removed    = old_tags - unchanged_tags
+      tags_added      = new_tags - unchanged_tags
+      
+      tags_removed.each do |tag|
+        coll.update({:_id => tag}, {'$inc' => {:value => -1}}, :upsert => true)
+      end
+
+      tags_added.each do |tag|
+        coll.update({:_id => tag}, {'$inc' => {:value => 1}}, :upsert => true)
+      end      
     end
     
-    def tags_changed?
-      !changed_tag_arrays.empty?
+    def update_tags_aggregations_on_save
+      tag_array_attributes.each do |context_array|
+        next if changes[context_array].nil?
+
+        old_tags, new_tags = changes[context_array]
+        update_tags_aggregation(context_array, old_tags, new_tags)
+      end
     end
     
-    def update_tags_aggregation
-      changed_tag_arrays.each do |field_name|
-        context = context_array_to_context_hash[field_name]
-        coll = self.class.db.collection(self.class.aggregation_collection_for(context))
-        field_name = self.class.tag_options_for(context)[:array_field]      
-        old_tags, new_tags = changes["#{field_name}"]
-        old_tags ||= []
-        new_tags ||= []
-        unchanged_tags  = old_tags & new_tags
-        tags_removed    = old_tags - unchanged_tags
-        tags_added      = new_tags - unchanged_tags
-
-        tags_removed.each do |tag|
-          coll.update({:_id => tag}, {'$inc' => {:value => -1}}, :upsert => true)
-        end
-
-        tags_added.each do |tag|
-          coll.update({:_id => tag}, {'$inc' => {:value => 1}}, :upsert => true)
-        end
+    def update_tags_aggregations_on_destroy
+      tag_array_attributes.each do |context_array|
+        old_tags = send context_array
+        new_tags = []
+        update_tags_aggregation(context_array, old_tags, new_tags)
       end      
     end
   end