dojo.provide("dojox.fx.Shadow");
dojo.experimental("dojox.fx.Shadow"); 

dojo.require("dijit._Widget"); 
dojo.require("dojo.NodeList-fx"); 

dojo.declare("dojox.fx.Shadow",
	dijit._Widget,{
	// summary: Adds a drop-shadow to a node.
	// 
	// example:
	// |	// add drop shadows to all nodes with class="hasShadow"
	// |	dojo.query(".hasShadow").forEach(function(n){
	// |		var foo = new dojox.fx.Shadow({ node: n });
	// |		foo.startup();
	// |	});
	//
	// shadowPng: String
	// 	Base location for drop-shadow images
	shadowPng: dojo.moduleUrl("dojox.fx", "resources/shadow"),

	// shadowThickness: Integer
	// 	How wide (in px) to make the shadow
	shadowThickness: 7,

	// shadowOffset: Integer
	//	How deep to make the shadow appear to be
	shadowOffset: 3,

	// opacity: Float
	//	Overall opacity of the shadow
	opacity: 0.75,

	// animate: Boolean	
	// 	A toggle to disable animated transitions
	animate: false,

	// node: DomNode
	// 	The node we will be applying this shadow to
	node: null,

	startup: function(){
		// summary: Initializes the shadow.

		this.inherited(arguments);
		this.node.style.position = "relative";
		// make all the pieces of the shadow, and position/size them as much
		// as possible (but a lot of the coordinates are set in sizeShadow
		this.pieces={};
		var x1 = -1 * this.shadowThickness;
		var y0 = this.shadowOffset;
		var y1 = this.shadowOffset + this.shadowThickness;
		this._makePiece("tl", "top", y0, "left", x1);
		this._makePiece("l", "top", y1, "left", x1, "scale");
		this._makePiece("tr", "top", y0, "left", 0);
		this._makePiece("r", "top", y1, "left", 0, "scale");
		this._makePiece("bl", "top", 0, "left", x1);
		this._makePiece("b", "top", 0, "left", 0, "crop");
		this._makePiece("br", "top", 0, "left", 0);

		this.nodeList = dojo.query(".shadowPiece",this.node);

		this.setOpacity(this.opacity);
		this.resize();
	},

	_makePiece: function(name, vertAttach, vertCoord, horzAttach, horzCoord, sizing){
		// summary: append a shadow pieces to the node, and position it
		var img;
		var url = this.shadowPng + name.toUpperCase() + ".png";
		if(dojo.isIE < 7){
			img = dojo.create("div");
			img.style.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+url+"'"+
				(sizing?", sizingMethod='"+sizing+"'":"") + ")";
		}else{
			img = dojo.create("img", { src:url });
		}

		img.style.position="absolute"; 
		img.style[vertAttach]=vertCoord+"px";
		img.style[horzAttach]=horzCoord+"px";
		img.style.width=this.shadowThickness+"px";
		img.style.height=this.shadowThickness+"px";
		dojo.addClass(img,"shadowPiece"); 
		this.pieces[name]=img;
		this.node.appendChild(img);

	},

	setOpacity: function(/* Float */n,/* Object? */animArgs){
		// summary: set the opacity of the underlay
		// note: does not work in IE? FIXME.
		if(dojo.isIE){ return; } 
		if(!animArgs){ animArgs = {}; } 
		if(this.animate){
			var _anims = [];
			this.nodeList.forEach(function(node){
				_anims.push(dojo._fade(dojo.mixin(animArgs,{ node: node, end: n })));
			});
			dojo.fx.combine(_anims).play();
		}else{
			this.nodeList.style("opacity",n);
		}	

	},

	setDisabled: function(/* Boolean */disabled){
		// summary: enable / disable the shadow
		if(disabled){
			if(this.disabled){ return; }
			if(this.animate){ this.nodeList.fadeOut().play(); 
			}else{ this.nodeList.style("visibility","hidden"); }
			this.disabled = true;
		}else{
			if(!this.disabled){ return; }
			if(this.animate){ this.nodeList.fadeIn().play(); 
			}else{ this.nodeList.style("visibility","visible"); }
			this.disabled = false;
		}
	},

	resize: function(/* dojox.fx._arg.ShadowResizeArgs */args){
		// summary: Resizes the shadow based on width and height.
		var x; var y;
		if(args){ x = args.x; y = args.y;
		}else{
			var co = dojo._getBorderBox(this.node); 
			x = co.w; y = co.h; 
		}
		var sideHeight = y - (this.shadowOffset+this.shadowThickness);
		if (sideHeight < 0) { sideHeight = 0; }
		if (y < 1) { y = 1; }
		if (x < 1) { x = 1; }
		with(this.pieces){
			l.style.height = sideHeight+"px";
			r.style.height = sideHeight+"px";
			b.style.width = x+"px";
			bl.style.top = y+"px";
			b.style.top = y+"px";
			br.style.top = y+"px";
			tr.style.left = x+"px";
			r.style.left = x+"px";
			br.style.left = x+"px";
		}
	}
});