/**************************************************
 * draglayer.js
 * 08.21.2007
 * Responsible for making a layer draggable 
 * Based on DomDrag by Aaron Boodman
 **************************************************/

var DragLayer = {
	obj : null,

	init : function(o, posX, posY, oRoot, minX, maxX, minY, maxY, bSwapHorzRef, bSwapVertRef, fXMapper, fYMapper) {
		o.onmousedown = DragLayer.start;
		o.hmode = bSwapHorzRef ? false : true;
		o.vmode = bSwapVertRef ? false : true;
		o.root = oRoot && oRoot != null ? oRoot : o;

		if (o.hmode) {
			if (!isNaN(parseInt(posX))) {
				o.root.style.left   = posX + "px";
			} else {
				o.root.style.left   = "0px";
			}
		}
//		if (o.hmode && isNaN(parseInt(o.root.style.left))) {
//			o.root.style.left   = "0px";
//		}
		if (o.vmode) {
			if (!isNaN(parseInt(posY))) {
				o.root.style.top   = posY + "px";
			} else {
				o.root.style.top   = "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 = DragLayer.obj = this;
		e = DragLayer.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	= DragLayer.drag;
		document.onmouseup = DragLayer.end;
		return false;
	},

	drag : function(e) 	{
		e = DragLayer.fixE(e);
		var o = DragLayer.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)

		DragLayer.obj.root.style[o.hmode ? "left" : "right"] = nx + "px";
		DragLayer.obj.root.style[o.vmode ? "top" : "bottom"] = ny + "px";
		DragLayer.obj.lastMouseX = ex;
		DragLayer.obj.lastMouseY = ey;

		DragLayer.obj.root.onDrag(nx, ny);
		return false;
	},

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