var _startX = 0;			// mouse starting positions
var _startY = 0;
var _offsetX = 0;			// current element offset
var _offsetY = 0;
var _dragElement;			// needs to be passed from OnMouseDown to OnMouseMove
var _oldZIndex = 0;		// we temporarily increase the z-index during drag
var maxleft = -270;
var maxright = 270;
var final, result, container;

InitDragDrop();

function InitDragDrop(){
	document.onmousedown = OnMouseDown;
	document.onmouseup = OnMouseUp;
}

function OnMouseDown(e){
	// IE is retarded and doesn't pass the event object
	if (e == null) 
		e = window.event; 
	
	// IE uses srcElement, others use target
	var target = e.target != null ? e.target : e.srcElement;

	// for IE, left click == 1
	// for Firefox, left click == 0
	if ((e.button == 1 && window.event != null || e.button == 0) && target.className == 'drag'){
		// grab the mouse position
		_startX = e.clientX;
		_startY = e.clientY;
		
		// grab the clicked element's position
		_offsetX = ExtractNumber(target.style.left);
		_offsetY = ExtractNumber(target.style.top);
		
		// bring the clicked element to the front while it is being dragged
		_oldZIndex = target.style.zIndex;
		target.style.zIndex = 10000;
		container = target.previousSibling.previousSibling.id;
		
		// we need to access the element in OnMouseMove
		_dragElement = target;

		// tell our code to start moving the element with the mouse
		document.onmousemove = OnMouseMove;
		
		// cancel out any text selections
		document.body.focus();
		
		// prevent text selection in IE
		document.onselectstart = function () { return false; };
		// prevent IE from trying to drag an image
		target.ondragstart = function() { return false; };
		
		// prevent text selection (except IE)
		return false;
	}
}

function ExtractNumber(value){
	var n = parseInt(value);
	return n == null || isNaN(n) ? 0 : n;
}

function OnMouseMove(e){
	if (e == null) 
		var e = window.event; 
	// this is the actual "drag code"
	_dragElement.style.left = (_offsetX + e.clientX - _startX) + 'px';
	if(parseInt(_dragElement.style.left, 10)< maxleft){ _dragElement.style.left = maxleft + 'px'; }
	if(parseInt(_dragElement.style.left, 10)> maxright){ _dragElement.style.left = maxright + 'px'; }
	_dragElement.style.top = 0 + 'px'; //_dragElement.style.top = (_offsetY + e.clientY - _startY) + 'px'; normal free movement
}

function OnMouseUp(e){
	if (_dragElement != null){
		_dragElement.style.zIndex = _oldZIndex;
		// we're done with these events until the next OnMouseDown
		document.onmousemove = null;
		document.onselectstart = null;
		_dragElement.ondragstart = null;

		// this is how we know we're not dragging
		var final = parseInt(_dragElement.style.left, 10);
		if(final >= 0 && final < 140){ result = 2; }
		if(final >= 140 && final < 280){ result = 3; }
		if(final == 280){ result = 4; }
		if(final < 0 && final > -140){ result = 1; }
		if(final < -140 && final >= -280){ result = 0; }
		document.getElementById(container).value = result;
		_dragElement = null;
	}
}

// this is simply a shortcut for the eyes and fingers
function $(id){
	return document.getElementById(id);
}