/* This class has been originally developed by David Walsh
 * All modifications from this version by Thomas Beck 
 */
var LinkAlert = new Class({

	//implements
	Implements: [Options,Events],

	//options
	options: {
		container: document.body,
		extensions: {},
		offsets: { x:6, y:-15 },
		preloadImages: true,
		protocols: {},
		sticky: false,
		onShow: function(el,image) {
			this.image.setStyle('display','');
		},
		onHide: function(el,image) {
			this.image.setStyle('display','none');
		}
	},
	
	//initialization
	initialize: function(options) {
		//set options
		this.setOptions(options);
		this.extensions = new Hash(this.options.extensions);
		this.protocols = new Hash(this.options.protocols);
		this.image = new Element('img',{
			src: '',
			styles: {
				position: 'absolute',
				top: -200,
				left: -200,
				visibility: 'hidden'
			}
		}).inject($(document.body));
		//preload images, if necessary
		if(this.options.preloadImages) { this.preloadImages(); }
		//add the listeners
		this.addListeners(this.extensions,'$=','extensions');
		this.addListeners(this.protocols,'^=','protocols');
	},
	
	//give direction to links
	addListeners: function(items,sep,type) {
		//for every item
		items.each(function(image,extension,type) {
			//for every link of that type
			$$('a[href' + sep + '\'' + extension + '\']').each(function(el) {
				//if the same protocol, don't bother showing
				if(type == 'protocol' && window.location.protocol == extension + ':') { return; }
				//add the show/hide events
				el.addEvents({
					mouseenter: function(e) {
						//position the image and give it the proper SRC
						this.reposition(e).set('src',image);
						//fire the event
						this.fireEvent('show',[el,image]);
					}.bind(this),
					mouseleave: function(e) {
						//fire the event
						this.fireEvent('hide',[el,image]);
					}.bind(this)
				});
				//sticky?
				if(this.options.sticky) {
					el.addEvent('mousemove',function(e) {
						this.reposition(e);
					}.bind(this));
				}
			},this);
		},this);
	},
	
	//repositions
	reposition: function(e) {
		return this.image.setStyles({
			left: e.page.x + this.options.offsets.x,
			top: e.page.y + this.options.offsets.y
		});
	},
	
	//preloads necessary images
	preloadImages: function() {
		var images = [this.protocols.getValues(),this.extensions.getValues()].flatten();
		new Asset.images(images);
	}
});