/**************************************************

 * 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	= Drag.start;

		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;

		o.root.onDragStart	= new Function();

		o.root.onDragEnd	= new Function();

		o.root.onDrag		= new Function();

	},

	start : function(e)

	{

		var o = Drag.obj = this;

		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 o = Drag.obj;

		var ey	= e.clientY;

		var ex	= e.clientX;

		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 );

		var nx, ny;

		if (o.minX != null) ex = o.hmode ? Math.max(ex, o.minMouseX) : Math.min(ex, o.maxMouseX);

		if (o.maxX != null) ex = o.hmode ? Math.min(ex, o.maxMouseX) : Math.max(ex, o.minMouseX);

		if (o.minY != null) ey = o.vmode ? Math.max(ey, o.minMouseY) : Math.min(ey, o.maxMouseY);

		if (o.maxY != null) ey = o.vmode ? Math.min(ey, o.maxMouseY) : Math.max(ey, o.minMouseY);

		nx = x + ((ex - o.lastMouseX) * (o.hmode ? 1 : -1));

		ny = y + ((ey - o.lastMouseY) * (o.vmode ? 1 : -1));

		if (o.xMapper)		nx = o.xMapper(y)

		else if (o.yMapper)	ny = o.yMapper(x)

		Drag.obj.root.style[o.hmode ? "left" : "right"] = nx + "px";

		Drag.obj.root.style[o.vmode ? "top" : "bottom"] = ny + "px";

		Drag.obj.lastMouseX	= ex;

		Drag.obj.lastMouseY	= ey;

		Drag.obj.root.onDrag(nx, ny);

		return false;

	},

	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;

	}

};