/**
	* @package			overlay.js
	* @dependence		prototype.js - v1.5.1.1
	* @version			0.1.1
	* browser test		FF 2.0.0.x and IE 6.0
	* @license			GNU GPL 2.0
	* @author 			Alvaro A. Lima Jr <alvarolimajr@gmail.com>
	* @copyright 		Alvaro Junior! <http://alvarojunior.net>
	* FIX BUG : onresize
	*/
	if(typeof(Prototype) == 'undefined' || parseFloat(Prototype.Version) < 1.5)
		throw("overlay.js requires the Prototype JavaScript framework >= 1.5.0");

		//
		// getPageSize()
		// Returns array with page width, height and window width, height
		// Core code from - quirksmode.org
		// Edit for Firefox by pHaez
		//
		function getPageSize(){

			var xScroll, yScroll;

			if (window.innerHeight && window.scrollMaxY) {
				xScroll = document.body.scrollWidth;
				yScroll = window.innerHeight + window.scrollMaxY;
			} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
				xScroll = document.body.scrollWidth;
				yScroll = document.body.scrollHeight;
			} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
				xScroll = document.body.offsetWidth;
				yScroll = document.body.offsetHeight;
			}

			var windowWidth, windowHeight;
			if (self.innerHeight) {	// all except Explorer
				windowWidth = self.innerWidth;
				windowHeight = self.innerHeight;
			} else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
				windowWidth = document.documentElement.clientWidth;
				windowHeight = document.documentElement.clientHeight;
			} else if (document.body) { // other Explorers
				windowWidth = document.body.clientWidth;
				windowHeight = document.body.clientHeight;
			}

			// for small pages with total height less then height of the viewport
			if(yScroll < windowHeight){
				pageHeight = windowHeight;
			} else {
				pageHeight = yScroll;
			}
				// for small pages with total width less then width of the viewport
			if(xScroll < windowWidth){
				pageWidth = windowWidth;
			} else {
				pageWidth = xScroll;
			}
			return {pageWidth: pageWidth ,pageHeight: pageHeight , windowWidth: windowWidth, windowHeight: windowHeight};
		}

	if (!window.Overlay)
		var Overlay = {};
	/**
	* Usage :
	*  - Overlay.show(options);
	*  -- options = {color : '#fffccc', opacity: 0.4};
	*/
	Overlay.Methods = {
		/**
		* @access public
		*/
		version: '0.1.1',

		/**
		* @access protected
		*/
		_isInitialized : false,

		/**
		* document.body
		* @access protected
		*/
		_body : null,

		/**
		* obj div
		* @access protected
		*/
		_overlay : null,

		/**
		* Método construtor
		* @access private
		*/
		__init__: function(options){
			this._setOptions(options);
			this._createDivOverlay();
			this._resize();
			this._isInitialized = true;
		},

		/**
		* @access protected
		*/
		_setOptions: function(options) {
			this.options = {
				color: '#000',
				opacity: '0.6'
			};
			Object.extend(this.options, options || {});
		},

		/**
		* @access protected
		*/
		_createDivOverlay: function(){
			if(!$('overlay')){
				this._body = document.getElementsByTagName('body').item(0);
				this._overlay = $(document.createElement('div'));
				this._overlay.setAttribute('id','overlay');
				this._overlay.setStyle({
					display : 'none',
					backgroundColor : this.options.color,
					position : 'absolute',
					top : '0px',
					left : '0px'
				});
				this._body.insertBefore(this._overlay, this._body.firstChild);
			} else {
				this._overlay = $('overlay');
			}
		},

		/**
		* @access public
		*/
		show: function(options){
			if(!this._isInitialized)
				this.__init__(options);

			var pageSize = getPageSize();
			this._overlay.show();
			var w = Prototype.Browser.IE ? pageSize.pageWidth + 'px' : '100%';

			this._overlay.setOpacity(this.options.opacity);
			this._overlay.setStyle({height: pageSize.pageHeight + 'px', width: w, zIndex: '998'});
		},

		/**
		* @access public
		*/
		hide: function(){
			this._overlay.hide();
		},

		/**
		* @access protected
		*/
		_resize: function(){
			window.onresize = function(){
				if(Overlay._overlay.getStyle('display') == 'block')
					Overlay.show();
			}
		}
	}
	Object.extend(Overlay, Overlay.Methods);