var overlayDurationTaf = 0.3;

function initTaf() {
	var objBody = document.getElementsByTagName("body").item(0);
		
	var objOverlay = document.createElement("div");
	objOverlay.setAttribute('id','tafOverlay');
	objOverlay.style.display = 'none';
	objOverlay.onclick = function() { closeTAF(); }
	objBody.appendChild(objOverlay);
}

function openTAF(){
	$$('select', 'object', 'embed').each(function(node){ node.style.visibility = 'hidden' });
	
	var arrayPageSize = getPageSize();
	$('tafOverlay').setStyle({ width: arrayPageSize[0]+'px' });
	$('tafOverlay').setStyle({ height: arrayPageSize[1]+'px' });
	$('tafOverlay').appear({ duration: overlayDurationTaf, from: 0.0, to: 0.5 });
	
	new Effect.Opacity('taf', {duration:0.0, from:0.0, to:0.0});
	$('taf').style.display = "block";
	
	var tafHeight = $('taf').offsetHeight;
	var tafWidth = $('taf').offsetWidth;
	
	$('taf').style.display = "none";
	
	var arrayPageScroll = getPageScroll();
	var lightboxTop = arrayPageScroll[1] + (arrayPageSize[3] / 2) - (tafHeight / 2);
	var lightboxLeft = arrayPageScroll[0] + (arrayPageSize[0] / 2) - (tafWidth / 2);
	$('taf').setStyle({ top: lightboxTop+'px' });
	$('taf').setStyle({ left: lightboxLeft+'px' });
	
	new Effect.Appear('taf', {duration:overlayDurationTaf, from:0.0, to:1});
}

function closeTAF(){
	new Effect.Fade('tafOverlay', { duration: overlayDurationTaf});
	$$('select', 'object', 'embed').each(function(node){ node.style.visibility = 'visible' });
	new Effect.Fade('taf', { duration: overlayDurationTaf});
}

function toggleTAF(){
	if(document.getElementById('taf').style.display == "none"){
		openTAF();	
	}else{
		closeTAF();
	}
}

function getPageSize(){
	
	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;
	
//	console.log(self.innerWidth);
//	console.log(document.documentElement.clientWidth);

	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;
	}

//	console.log("xScroll " + xScroll)
//	console.log("windowWidth " + windowWidth)

	// for small pages with total width less then width of the viewport
	if(xScroll < windowWidth){	
		pageWidth = xScroll;		
	} else {
		pageWidth = windowWidth;
	}
//	console.log("pageWidth " + pageWidth)

	arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
	return arrayPageSize;
}

function validateTAF() {	
	sendersName  = document.getElementById("name1");
	sendersEmail = document.getElementById("email1");
	friendsName  = document.getElementById("name2");
	friendsEmail = document.getElementById("email2");
	
	if(!sendersName.value
	   		|| !friendsName.value
	   		|| !sendersEmail.value
	   		|| !friendsEmail.value){
		alert('please fill out all required fields') ;
		return false;
	}else{
		return true;	
	}
}
	
function getPageScroll(){

	var xScroll, yScroll;

	if (self.pageYOffset) {
		yScroll = self.pageYOffset;
		xScroll = self.pageXOffset;
	} else if (document.documentElement && document.documentElement.scrollTop){	 // Explorer 6 Strict
		yScroll = document.documentElement.scrollTop;
		xScroll = document.documentElement.scrollLeft;
	} else if (document.body) {// all other Explorers
		yScroll = document.body.scrollTop;
		xScroll = document.body.scrollLeft;	
	}

	arrayPageScroll = new Array(xScroll,yScroll) 
	return arrayPageScroll;
}

Event.observe(window, 'load', initTaf, false);