/*
 * alfredo.cerutti@intercom.it
 * 
 * simple class to lock screen and present a div
 */

var OverlayDiv = Class.create();

OverlayDiv.prototype = {
	initialize: function(div_to_show, top_positive, top_negative){
		
		this.top_positive = top_positive;
		this.top_negative = top_negative;
		this.div_to_show = div_to_show;
		
		this.centerDiv();		
		this.start();
		
		var objBody = $$('body')[0];	
		
		$('overlay').hide().observe('click', (function() { this.end(); }).bind(this));

/*		var th = this;
		(function(){
			var ids = 'overlay';
			$w(ids).each(function(id){
				th[id] = $(id);
			});
		}).defer();
		*/
	},
	
	centerDiv: function() {
		var arrayPageSize = this.getPageSize();
		var newleft= (arrayPageSize[0]/2) - ($(this.div_to_show).getDimensions().width /2);
		$(this.div_to_show).setStyle({left: newleft + 'px'})
	},
	
	start: function(){
		// stretch overlay to fill page and fade in
		var arrayPageSize = this.getPageSize();
		$('overlay').setStyle({
			width: arrayPageSize[0] + 'px',
			height: arrayPageSize[1] + 'px'
		});
		
		new Effect.Appear('overlay', {
			duration: 0.2,
			from: 0.0,
			to: 0.8
		});

		$(this.div_to_show).morph('top: ' + this.top_positive+'px; ');
	},
	
    end: function() {
        //new Effect.Fade(this.div_to_show, { duration: 0.2 });
		$(this.div_to_show).morph('top: -' + this.top_negative+'px; ');		
        new Effect.Fade('overlay', { duration: 0.2 });
    },
	
	
    getPageSize: function() {
	        
	     var xScroll, yScroll;
		
		if (window.innerHeight && window.scrollMaxY) {	
			xScroll = window.innerWidth + window.scrollMaxX;
			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
			if(document.documentElement.clientWidth){
				windowWidth = document.documentElement.clientWidth; 
			} else {
				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 = xScroll;		
		} else {
			pageWidth = windowWidth;
		}

		return [pageWidth,pageHeight];
	}		
}