dojo.provide("dojo.dnd.TimedMoveable");

dojo.require("dojo.dnd.Moveable");

(function(){
	// precalculate long expressions
	var oldOnMove = dojo.dnd.Moveable.prototype.onMove;
		
	dojo.declare("dojo.dnd.TimedMoveable", dojo.dnd.Moveable, {
		// summary:
		//	A specialized version of Moveable to support an FPS throttling.
		//	This class puts an upper restriction on FPS, which may reduce 
		//	the CPU load. The additional parameter "timeout" regulates
		//	the delay before actually moving the moveable object.
		
		// object attributes (for markup)
		timeout: 40,	// in ms, 40ms corresponds to 25 fps
	
		constructor: function(node, params){
			// summary: an object, which makes a node moveable with a timer
			// node: Node: a node (or node's id) to be moved
			// params: Object: an optional object with additional parameters.
			//	See dojo.dnd.Moveable for details on general parameters.
			//	Following parameters are specific for this class:
			//		timeout: Number: delay move by this number of ms
			//			accumulating position changes during the timeout
			
			// sanitize parameters
			if(!params){ params = {}; }
			if(params.timeout && typeof params.timeout == "number" && params.timeout >= 0){
				this.timeout = params.timeout;
			}
		},
	
		// markup methods
		markupFactory: function(params, node){
			return new dojo.dnd.TimedMoveable(node, params);
		},
	
		onMoveStop: function(/* dojo.dnd.Mover */ mover){
			if(mover._timer){
				// stop timer
				clearTimeout(mover._timer)
				// reflect the last received position
				oldOnMove.call(this, mover, mover._leftTop)
			}
			dojo.dnd.Moveable.prototype.onMoveStop.apply(this, arguments);
		},
		onMove: function(/* dojo.dnd.Mover */ mover, /* Object */ leftTop){
			mover._leftTop = leftTop;
			if(!mover._timer){
				var _t = this;	// to avoid using dojo.hitch()
				mover._timer = setTimeout(function(){
					// we don't have any pending requests
					mover._timer = null;
					// reflect the last received position
					oldOnMove.call(_t, mover, mover._leftTop);
				}, this.timeout);
			}
		}
	});
})();