-- 技能撤销操作
-- 删除技能轨迹
function Commands:deleteTrack(ce, track)
	local releaseTrack = false
	local function redo()
		-- 如果preTrack不为空
		local preTrack = track:getPrevTrack()
		if preTrack ~= nil then
			track.PrevTrack = preTrack;
			preTrack:setNextTrack(-1);
		end
		
		-- nextTrack不为空
		local nextTrack = track:getNextTrack()
		if nextTrack ~= nil then
			track.NextTrack = nextTrack
			track:setNextTrack(-1)
		end
		
		track:retain()
		releaseTrack = true
		-- 移除这个轨迹
		track:removeFromParent();
		-- 更新树
		app.cs.updateCombineTree();
		-- 选中空
		app.cs.selectTrackObject(ce);
		return true;
	end
	
	local function undo()
		ce:addTrack(track);
		track:release()
		releaseTrack = false
		if not tolua.isnull(track.PrevTrack) then
			track.PrevTrack:setNextTrack(track:getTrackId())
		end
		
		if not tolua.isnull(track.NextTrack) then
			track:setNextTrack(track.NextTrack:getTrackId())
		end
		
		app.cs.updateCombineTree();
		app.cs.selectTrackObject(track);
	end
	
	local function clear()
		if releaseTrack then
			track:release()
		end
	end
	
	return {redo = redo , undo = undo, clear = clear};
end

-- 创建技能轨迹
function Commands:createTrack(ce, track)
	local releaseTrack = false
	local function redo()
		-- 如果preTrack不为空
		local preTrack = track:getPrevTrack()
		if preTrack ~= nil then
			track.PrevTrack = preTrack;
			preTrack:setNextTrack(-1);
		end
		
		-- nextTrack不为空
		local nextTrack = track:getNextTrack()
		if nextTrack ~= nil then
			track.NextTrack = nextTrack
			track:setNextTrack(-1)
		end
		
		-- 添加
		ce:addTrack(track);
		if releaseTrack then
			track:release()
			releaseTrack = false
		end
		-- 更新树
		app.cs.updateCombineTree();
		-- 选中空
		app.cs.selectTrackObject(track);
		return true;
	end
	
	local function undo()
		if not tolua.isnull(track.PrevTrack) then
			track.PrevTrack:setNextTrack(track:getTrackId())
		end
		
		if not tolua.isnull(track.NextTrack) then
			track:setNextTrack(track.NextTrack:getTrackId())
		end
		
		track:retain()
		releaseTrack = true
		-- 移除这个轨迹
		track:removeFromParent();
		app.cs.updateCombineTree();
		app.cs.selectTrackObject(ce);
	end
	
	local function clear()
		if releaseTrack then
			track:release()
		end
	end
	
	return {redo = redo , undo = undo, clear = clear};
end