var dragObject  = null;
var mouseOffset = null;
var dragContainer = null;

function getCanvasWidth() { 
    if (document.getElementById&&document.all) {
	    return document.body.offsetWidth
    } else if(document.all&&!window.print){ 
	    return document.body.offsetWidth
    } else if(document.getElementById&&!document.all){ 
	    return document.body.innerWidth
    } else if(document.layers){ 
	    return document.body.innerWidth
    } else { 
    } 
} 

function getCanvasHeight() { 
if (document.getElementById&&document.all) {
	return document.body.offsetHeight
} else if(document.all&&!window.print){ 
	return document.body.offsetHeight
} else if(document.getElementById&&!document.all){ 
	return document.body.innerHeight
} else if(document.layers){ 
	return document.body.innerHeight
} else { 
} 
} 

function makeContainer(item){
	dragContainer = item;
	dragContainer.style.position = 'relative';
	dragContainer.style.overflow = 'hidden';
}

function getMouseOffset(target, ev){
	ev = ev || window.event;

	var docPos    = getPosition(target);
	var mousePos  = mouseCoords(ev);

	return {x:mousePos.x - docPos.x, y:mousePos.y - docPos.y};
}

function getPosition(obj){
	var left = 0;
	var	top = 0;
	
	if (obj.offsetParent) {

		left += obj.offsetLeft ;
		top += obj.offsetTop;		
		
		while (obj = obj.offsetParent) {
			if (parseInt(obj.style.left)) {
				left -= parseInt(obj.style.left);
				top -= parseInt(obj.style.top);
			}
		}
	}
	return {x:left, y:top};
}

function mouseCoords(ev){
	if(ev.pageX || ev.pageY){
		return {x:ev.pageX, y:ev.pageY};
	}
	return {
		x:ev.clientX + document.body.scrollLeft - document.body.clientLeft,
		y:ev.clientY + document.body.scrollTop  - document.body.clientTop
	};
}

function mouseMove(ev){
	ev           = ev || window.event;
	var mousePos = mouseCoords(ev);
	var targWidth, targHeight, targPos;
	var browseWidth, browseHeight;

	browseWidth		=	getCanvasWidth();
	browseHeight	=	getCanvasHeight();

	if(dragObject){	
		if (dragContainer) {
			targWidth  = parseInt(dragContainer.offsetWidth);
			targHeight = parseInt(dragContainer.offsetHeight);
			if (((mousePos.y - mouseOffset.y) < 0) && ((mousePos.y - mouseOffset.y + dragObject.height) > (targHeight)))	{dragObject.style.top	= (mousePos.y - mouseOffset.y) + 'px';}
			if (((mousePos.x - mouseOffset.x) < 0) && ((mousePos.x - mouseOffset.x + dragObject.width) > (targWidth)))	{dragObject.style.left	= (mousePos.x - mouseOffset.x) + 'px';}
		} else {
			dragObject = null;
		}
		return false;
	}
}

function mouseUp(){
		dragObject = null;
}

function makeDraggable(item){
	if(!item) return;
	try {item.style.cursor = 'pointer';} catch (e) {} //cursor property breaks IE5.5
	item.onmousedown = function(ev){		
		dragObject  = this;
		dragObject.style.position = 'absolute';
		mouseOffset = getMouseOffset(this, ev);
		return false;
	}
}

function enableDrag(spContainer, imgDrag, imgWidth, imgHeight) {

	var dragItem = null;
	var dragCont = null;
	var contW, contH = 0;
	var top, left;
	
	document.onmousemove = mouseMove;
	document.onmouseup   = mouseUp;
	
	dragCont = document.getElementById(spContainer);
	makeContainer(dragCont);

	dragItem = document.getElementById(imgDrag);
	makeDraggable(dragItem);
	dragItem.style.position = 'absolute';
	
	dragItem.style.height = imgHeight + 'px'; dragItem.style.width = imgWidth + 'px';
	
	dragItem.style.top = 0; dragItem.style.left = 0;
	dragItem.top = 0; dragItem.left = 0;
		
	top = -((parseInt(dragItem.style.height)/2) - (parseInt(dragCont.style.height)/2));
	left = -((parseInt(dragItem.style.width)/2) - (parseInt(dragCont.style.width)/2));
	
	dragItem.style.top = top +'px';
	dragItem.style.left = left+'px';
	
	dragItem.top = dragItem.style.top;
	dragItem.left = dragItem.style.left;
	
	dragItem.alt = 'Click and hold to drag image';	
}


var ImageUrl;
var ImageZoomUrl;

var oZoomImage = new Image();
var tZoomLoaded;
	
function ReplaceImageFromThumb(imageUrl, imageZoomUrl) {
	ImageUrl = imageUrl;
	ImageZoomUrl = imageZoomUrl;
	
	HideZoomImage();
	PopulateImages();
}

function PopulateImages(){
	//document.getElementById('imgMainImageZoom').src = '';
	if (document.getElementById('imgMainImage') != null)	{
		document.getElementById('imgMainImage').src = ImageUrl;
	};
}

function ShowZoomImage()	{
	oZoomImage = new Image();
	oZoomImage.src = ImageZoomUrl;					
						
	if (document.getElementById) { // DOM 3: IE5+, NS6, Firefox#
	
		document.getElementById("imgMainImage").style.display = "none";
		document.getElementById("dvMainImageZoom").style.display = "block";
		
		document.getElementById("hypZoomPlus").style.display = "none";
		document.getElementById("hypZoomMinus").style.display = "block";
		
		if (document.getElementById("hypDragImage") != null) {document.getElementById("hypDragImage").style.display = "block"};
		
	} else if (document.layers) { // Netscape 4
	
		document.imgMainImage.style.display = "none";
		document.dvMainImageZoom.style.display = "block";
		
		document.hypZoomPlus.style.display = "none";
		document.hypZoomMinus.style.display = "block";
		
		if (document.hypDragImage != null) {document.hypDragImage.style.display = "block"};
		
	} else if (document.all) { // IE 4
	
		document.all.imgMainImage.style.display = "none";
		document.all.dvMainImageZoom.style.display = "block";
		
		document.all.hypZoomPlus.style.display = "none";
		document.all.hypZoomMinus.style.display = "block";
		
		if (document.all.hypDragImage != null ){document.all.hypDragImage.style.display = "block"};						
	}
	
	if (!oZoomImage.complete) {
		document.getElementById('dvMainImageZoom').innerHTML = "Loading";
		tZoomLoaded = setInterval(checkZoomLoaded,'500');
	} else {
		checkZoomLoaded();
	}
	
}
	
function checkZoomLoaded(){
	if (oZoomImage.complete){
		document.getElementById('dvMainImageZoom').innerHTML = '<img id="imgMainImageZoom" src="' + oZoomImage.src + '" />';
		clearTimeout(tZoomLoaded);		
		enableDrag('dvMainImageZoom', 'imgMainImageZoom', 900, 900);					
	}
}

function HideZoomImage()	{
	if (document.getElementById) { // DOM 3: IE5+, NS6, Firefox#
		if (document.getElementById("imgMainImage") != null) {document.getElementById("imgMainImage").style.display = "block";};
		document.getElementById("dvMainImageZoom").style.display = "none";
		if (document.getElementById("hypZoomPlus") != null) {document.getElementById("hypZoomPlus").style.display = "block";};
		if (document.getElementById("hypZoomMinus") != null) {document.getElementById("hypZoomMinus").style.display = "none";};
		if (document.getElementById("hypDragImage") != null) {document.getElementById("hypDragImage").style.display = "none";};
	} else if (document.layers) { // Netscape 4
		if (document.imgMainImage != null) {document.imgMainImage.style.display = "block";};
		document.dvMainImageZoom.style.display = "none";
		if (document.hypZoomPlus != null) {document.hypZoomPlus.style.display = "block";};
		if (document.hypZoomMinus != null) {document.hypZoomMinus.style.display = "none";};
		if (document.hypDragImage != null) {document.hypDragImage.style.display = "none";};
	} else if (document.all) { // IE 4
		if (document.all.imgMainImage != null) {document.all.imgMainImage.style.display = "block";};
		document.all.dvMainImageZoom.style.display = "none";
		if (document.all.hypZoomPlus != null) {document.all.hypZoomPlus.style.display = "block";};
		if (document.all.hypZoomMinus != null) {document.all.hypZoomMinus.style.display = "none";};
		if (document.all.hypDragImage != null) {document.all.hypDragImage.style.display = "none";};
	}
			}