/**************************************************************

	Script		: Overlay
	Version		: 1.1
	Authors		: Samuel birch
	Desc		: Covers the window with a semi-transparent layer.
	Licence		: Open Source MIT Licence

**************************************************************/
var ua = navigator.userAgent.toLowerCase();
var isStrict = document.compatMode == 'CSS1Compat',
        isOpera = ua.indexOf("opera") > -1,
        isIE = ua.indexOf('msie') > -1,
        isIE7 = ua.indexOf('msie 7') > -1,
        isBorderBox = isIE && !isStrict,
        isSafari = (/webkit|khtml/).test(ua),
        isSafari3 = isSafari && !!(document.evaluate),
        isGecko = !isSafari && ua.indexOf('gecko') > -1,
        isWindows = (ua.indexOf('windows') != -1 || ua.indexOf('win32') != -1),
        isMac = (ua.indexOf('macintosh') != -1 || ua.indexOf('mac os x') != -1),
        isLinux = (ua.indexOf('linux') != -1);

var Overlay = new Class({	
	
	getOptions: function(){
		return {
			colour: '#000',
			opacity: 0.7,
			zIndex: 1,
			container: document.body,
			onClick: Class.empty
		};
	},

	initialize: function(options){
		this.setOptions(this.getOptions(), options);
		
		this.options.container = $(this.options.container);
		
		this.overlay = new Element('div').setProperty('id', 'Overlay').setStyles({
			position: 'absolute',
			left: '0px',
			top: '0px',
			width: '100%',
			zIndex: this.options.zIndex,
			backgroundColor: this.options.colour
		}).injectInside(this.options.container);
		
		this.overlay.addEvent('click', function(){
			this.options.onClick();
		}.bind(this));
		
		this.fade = new Fx.Style(this.overlay, 'opacity').set(0);
		this.position();
		
		window.addEvent('resize', this.position.bind(this));
	},
	
	getViewportHeight : function(){
        var height = window.innerHeight; // Safari
        var mode = document.compatMode;
        if((mode || isIE) && !isOpera){
            height = isStrict ? document.documentElement.clientHeight : document.body.clientHeight;
        }
        return height;
    },
	
	getDocumentHeight : function() {
		 var scrollHeight = isStrict ? document.documentElement.scrollHeight : document.body.scrollHeight;
         return Math.max(scrollHeight, this.getViewportHeight());	
	},
	
	position: function(){ 
		if(this.options.container == document.body){ 
			//var h = window.getScrollHeight()+'px'; 
			var h = this.getDocumentHeight()+'px'; 
			this.overlay.setStyles({top: '0px', height: h}); 
		}else{ 
			var myCoords = this.options.container.getCoordinates(); 
			this.overlay.setStyles({
				top: myCoords.top+'px', 
				height: myCoords.height+'px', 
				left: myCoords.left+'px', 
				width: myCoords.width+'px'
			}); 
		} 
	},
	
	show: function(){
		this.fade.start(0,this.options.opacity);
	},
	
	hide: function(){
		this.fade.start(this.options.opacity,0);
	}
	
});
Overlay.implement(new Options);

/*************************************************************/