/**************************************************
 * dom-drag.js
 * 09.25.2001
 * www.youngpup.net
 **************************************************
 * 10.28.2001 - fixed minor bug where events
 * sometimes fired off the handle, not the root.
 **************************************************/

var Drag = {

	obj : null,

	init : function(o, oRoot, minX, maxX, minY, maxY, bSwapHorzRef, bSwapVertRef, fXMapper, fYMapper)
	{
//		o.onmousedown = function() {alert('!!!!!!!!!')};
		o.onmousedown = Drag.start;
//		o.onmouseover = function() {alert('!!!!!!!!!')};

		o.hmode = bSwapHorzRef ? false : true ;
		o.vmode = bSwapVertRef ? false : true ;

		o.root = oRoot && oRoot != null ? oRoot : o ;

		if (o.hmode  && isNaN(parseInt(o.root.style.left  ))) o.root.style.left   = "0px";
		if (o.vmode  && isNaN(parseInt(o.root.style.top   ))) o.root.style.top    = "0px";
		if (!o.hmode && isNaN(parseInt(o.root.style.right ))) o.root.style.right  = "0px";
		if (!o.vmode && isNaN(parseInt(o.root.style.bottom))) o.root.style.bottom = "0px";

		o.minX	= typeof minX != 'undefined' ? minX : null;
		o.minY	= typeof minY != 'undefined' ? minY : null;
		o.maxX	= typeof maxX != 'undefined' ? maxX : null;
		o.maxY	= typeof maxY != 'undefined' ? maxY : null;

		o.xMapper = fXMapper ? fXMapper : null;
		o.yMapper = fYMapper ? fYMapper : null;

		if (!o.root.onDragStart)
			o.root.onDragStart	= function() {/*alert('onDragStart wrong');*/};
		if (!o.root.onDragEnd)
			o.root.onDragEnd	= new Function();
		if (!o.root.onDrag)
			o.root.onDrag		= new Function();

//		alert('o = ' + o + ', o.root = ' + o.root);
//		alert('o.id = ' + o.id + ', o.root.id = ' + o.root.id + ', oRoot.id = ' + oRoot.id);
	},

	start : function(e)
	{
//		alert('e = ' + e);
//		var o = Drag.obj = this;
		var o = Drag.obj = getEvtTargetOrThis(e, this);
//		alert('o = ' + o + ', o.root = ' + o.root);
//		alert('o.id = ' + o.id + ', o.root.id = ' + o.root.id + ', oRoot.id = ' + oRoot.id);
		if (!o.root)
		{
			return false;
		}
/*
		alert('o: ' + o + ', o.root: ' + o.root);
		alert('getEvtTarget(e).id = ' + getEvtTarget(e).id);
		alert('Drag.obj.id = ' + Drag.obj.id);
		alert('Drag.obj.root.id = ' + Drag.obj.root.id);
		alert('getEvtTarget(e).root.id = ' + getEvtTarget(e).root.id);
//*/
		e = Drag.fixE(e);
		var y = parseInt(o.vmode ? o.root.style.top  : o.root.style.bottom);
		var x = parseInt(o.hmode ? o.root.style.left : o.root.style.right);
		o.root.onDragStart(x, y);

		o.lastMouseX = e.clientX;
		o.lastMouseY = e.clientY;

		if (o.hmode) {
			if (o.minX != null)	o.minMouseX	= e.clientX - x + o.minX;
			if (o.maxX != null)	o.maxMouseX	= o.minMouseX + o.maxX - o.minX;
		} else {
			if (o.minX != null) o.maxMouseX = -o.minX + e.clientX + x;
			if (o.maxX != null) o.minMouseX = -o.maxX + e.clientX + x;
		}

		if (o.vmode) {
			if (o.minY != null)	o.minMouseY	= e.clientY - y + o.minY;
			if (o.maxY != null)	o.maxMouseY	= o.minMouseY + o.maxY - o.minY;
		} else {
			if (o.minY != null) o.maxMouseY = -o.minY + e.clientY + y;
			if (o.maxY != null) o.minMouseY = -o.maxY + e.clientY + y;
		}

		document.onmousemove = Drag.drag;
		document.onmouseup = Drag.end;

		return false;
	},

	drag : function(e)
	{
		e = Drag.fixE(e);
		var ey	= e.clientY;
		var ex	= e.clientX;
		Drag.doDrag(e, Drag.obj.root);
		Drag.obj.lastMouseX	= ex;
		Drag.obj.lastMouseY	= ey;
		return false;
	},

	doDrag : function(e, obj)
	{
		e = Drag.fixE(e);

		var ey	= e.clientY;
		var ex	= e.clientX;
		var y = parseInt(Drag.obj.vmode ? obj.style.top  : obj.style.bottom);
		var x = parseInt(Drag.obj.hmode ? obj.style.left : obj.style.right );
		var nx, ny;

		if (Drag.obj.minX != null) ex = Drag.obj.hmode ? Math.max(ex, Drag.obj.minMouseX) : Math.min(ex, Drag.obj.maxMouseX);
		if (Drag.obj.maxX != null) ex = Drag.obj.hmode ? Math.min(ex, Drag.obj.maxMouseX) : Math.max(ex, Drag.obj.minMouseX);
		if (Drag.obj.minY != null) ey = Drag.obj.vmode ? Math.max(ey, Drag.obj.minMouseY) : Math.min(ey, Drag.obj.maxMouseY);
		if (Drag.obj.maxY != null) ey = Drag.obj.vmode ? Math.min(ey, Drag.obj.maxMouseY) : Math.max(ey, Drag.obj.minMouseY);

		var dx = ((ex - Drag.obj.lastMouseX) * (Drag.obj.hmode ? 1 : -1));
		var dy = ((ey - Drag.obj.lastMouseY) * (Drag.obj.vmode ? 1 : -1));
		nx = x + dx;
		ny = y + dy;

		if (Drag.obj.xMapper)		nx = Drag.obj.xMapper(y)
		else if (Drag.obj.yMapper)	ny = Drag.obj.yMapper(x)

		if (!Drag.obj.hasXLock)
		{
			if (!Drag.obj.constraintX)
				obj.style[Drag.obj.hmode ? "left" : "right"] = nx + "px";
			else
				obj.style[Drag.obj.hmode ? "left" : "right"] = Drag.obj.constraintX(obj, nx, x) + "px";
		}
		if (!Drag.obj.hasYLock)
		{
			if (!Drag.obj.constraintY)
				obj.style[Drag.obj.vmode ? "top" : "bottom"] = ny + "px";
			else
				obj.style[Drag.obj.hmode ? "top" : "bottom"] = Drag.obj.constraintY(obj, ny, y) + "px";
		}

//		alert('obj: ' + obj + ', obj.id: ' + obj.id + ', obj.eventHandler: ' + obj.eventHandler);
		if (obj.onDrag)
			obj.onDrag(e, nx, ny, dx, dy);
		else
		{
//			alert('obj: ' + obj + ', obj.id: ' + obj.id + ', obj.code: ' + obj.code);
		}
		if (obj.eventHandler)
			obj.eventHandler.onDrag(e, nx, ny, dx, dy);
		else
		{
//			alert('obj: ' + obj + ', obj.id: ' + obj.id + ', obj.eventHandler: ' + obj.eventHandler);
		}
	},



	end : function()
	{
		document.onmousemove = null;
		document.onmouseup   = null;
		Drag.obj.root.onDragEnd(
			parseInt(Drag.obj.root.style[Drag.obj.hmode ? "left" : "right"]), 
			parseInt(Drag.obj.root.style[Drag.obj.vmode ? "top" : "bottom"])
		);
		Drag.obj = null;
	},

	fixE : function(e)
	{
		if (typeof e == 'undefined') e = window.event;
		if (typeof e.layerX == 'undefined') e.layerX = e.offsetX;
		if (typeof e.layerY == 'undefined') e.layerY = e.offsetY;
		return e;
	}
};