Register second event to make sure item is in bag before we attempt to stack.

GemStacker.lua

@@ -1,16 +1,16 @@
 GemStacker = LibStub('AceAddon-3.0'):NewAddon('GemStacker','AceConsole-3.0','AceEvent-3.0');
 local core = GemStacker;
 core.gems = {};
+core.lastGem = false;
 
 function core:OnInitialize()	
-	print('GemStacker: Initialized');
+
 end
 
 function core:OnEnable()
-	print('GemStacker: Enabled');
-	
 	core.gems['Puissant Dream Emerald'] = true;
 	
+	--use chat_msg_loot later
 	self:RegisterEvent('UNIT_SPELLCAST_SUCCEEDED','FindGemCast');
 end
 
@@ -18,47 +18,41 @@ function core:FindGemCast(_,unitId,spell,...)
 	print('GemStacker: Casted ',spell);
 	--should receive something like "player","Reckless Ember Topaz","",2,73369
 	if(unitId ~= 'player') then return end;
-	print('GemStacker: Player casted spell.');
 	if(not core.gems[spell]) then return end;
-	print('GemStacker: Gem found');
+	
+	core.lastGem = spell;
+	self:RegisterEvent('BAG_UPDATE','StackGem');
+end
+
+function core:StackGem(...)
+	print('GemStacker: StackGem');
+	if(not core.lastGem) then return end;
 	
 	local sourceContainer,sourceSlot,destContainer,destSlot = -1,-1,-1,-1;
-	for bag = 0,1 do
+	for bag = 0,4 do
 		for slot = 1,GetContainerNumSlots(bag) do
-			print('GemStacker: Checking ',bag,slot);
 			itemId = GetContainerItemID(bag,slot)
 			if(itemId) then
 				itemName = GetItemInfo(itemId);
-				if(spell == itemName) then
+				if(core.lastGem == itemName) then
-					print('GemStacker: Found gem in bag: ',bag,slot);
 					local _,count = GetContainerItemInfo(bag,slot);
 					if(count == 1 and sourceContainer < 0) then
-						print('GemStacker: Found source');
 						sourceContainer = bag;
 						sourceSlot = slot;
 					elseif(count < 20 and (count > 1 or destContainer < 0)) then
-						print('GemStacker: Found dest');
 						destContainer = bag;
 						destSlot = slot;
 					end
 				end
-			else
-				print('GemStacker: ',bag,slot,'emptry');
 			end
 		end
 	end
 
-	if(sourceContainer < 0 and destContainer < 0) then
+	if(sourceContainer ~= -1 and destContainer ~= -1) then
-		print('GemStacker: Stacking');
 		PickupContainerItem(sourceContainer,sourceSlot);
 		PickupContainerItem(destContainer,destSlot)
-	end
+	end	
-	
-	--self:RegisterEvent('BAG_UPDATE','StackGem');
-end
-
-function core:StackGem(...)
-	
 	
+	core.lastGem = false;
 	self:UnregisterEvent('BAG_UPDATE');
 end