/**************************************************
 * 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;
	}
};

function CalcDiff() {
	var dimensions = Element.getDimensions('container');
	var container_height = dimensions.height;
	dimensions = Element.getDimensions('content');
	var contained_height = dimensions.height;
	var diff = contained_height - container_height;
	return diff;
}

function CalcSDiff () {
	var handle_top = parseInt(document.getElementById('scroller').style.top);
	dimensions = Element.getDimensions('scrollArea');
	var scrollbar_length = dimensions.height;
	dimensions = Element.getDimensions('scroller');
	var handle_length = dimensions.height;
	var hdiff = scrollbar_length - handle_length;
	return hdiff
}

function Down() {
	var cdiff = CalcDiff();
	var sdiff = CalcSDiff();
	var pos = parseInt(document.getElementById('content').style.top);
	if (isNaN(pos))
	{
		pos = 0;
	}
	if ((pos - 20) < (0 - cdiff - 20))
	{
		var v_val = 0 - cdiff - 20;
	} else {
		var v_val = pos - 20;
	}
	document.getElementById('content').style.top = v_val + "px";
	
	var new_top = (((0 - v_val) / cdiff) * sdiff)
	document.getElementById('scroller').style.top = String(new_top) + "px";
	//alert("pos:" + pos + ", sdiff" + sdiff);
}

function Up() {
	var cdiff = CalcDiff();
	var sdiff = CalcSDiff();
	var pos = parseInt(document.getElementById('content').style.top);
	if (isNaN(pos))
	{
		pos = 0;
	}
	if ((pos + 20) > 10)
	{
		var v_val = 10;
	} else {
		var v_val = pos + 20;
	}
	document.getElementById('content').style.top = v_val + "px";
//	var pos = document.getElementById('container').scrollTop;
//	var v_val = pos - 20;
//	document.getElementById('container').scrollTop = v_val;
	
	var new_top = (((0 - v_val) / cdiff) * sdiff)
	document.getElementById('scroller').style.top = String(new_top) + "px";
	//alert("v_val:" + v_val + ", new_top" + new_top);
}

function nDown() {
	var diff = CalcDiff();
	var pos = document.getElementById('container').scrollTop;
	var v_val = pos + (diff/10);
	document.getElementById('container').scrollTop = v_val;
	var handle_top = parseInt(document.getElementById('handle').style.top);
	var scrollbar_length = parseInt(document.getElementById('track').style.height);
	var handle_length = parseInt(document.getElementById('handle').style.height);
	var top_new = handle_top + ((scrollbar_length-handle_length) / 10);
	if (top_new > (scrollbar_length-handle_length)) 
	{
		top_new = scrollbar_length-handle_length;
	}
	top_new = String(top_new) + 'px';
	document.getElementById('handle').style.top = top_new;
}

function nUp() {
	var diff = CalcDiff();
	var pos = document.getElementById('container').scrollTop;
	var v_val = pos - (diff/10);
	document.getElementById('container').scrollTop = v_val;
	var handle_top = parseInt(document.getElementById('handle').style.top);
	var scrollbar_length = parseInt(document.getElementById('track').style.height);
	var handle_length = parseInt(document.getElementById('handle').style.height);
	var top_new = handle_top - ((scrollbar_length-handle_length) / 10);
	if (top_new < 0) 
	{
		top_new = 0;
	}
	top_new = String(top_new) + 'px';
	document.getElementById('handle').style.top = top_new;
}

/** This is high-level function.
 * It must react to delta being more/less than zero.
 */
function handle(delta) {
	if (delta < 0)
		Down();
	else
		Up();
}

/** Event handler for mouse wheel event.
 */
function wheel(event){
	var delta = 0;
	if (!event) /* For IE. */
		event = window.event;
	if (event.wheelDelta) { /* IE/Opera. */
		delta = event.wheelDelta/120;
		/** In Opera 9, delta differs in sign as compared to IE.*/
	if (window.opera)
		delta = -delta;
	} else if (event.detail) { /** Mozilla case. */
		/** In Mozilla, sign of delta is different than in IE.
		* Also, delta is multiple of 3.	*/
		delta = -event.detail/3;
	}
/** If delta is nonzero, handle it.
  * Basically, delta is now positive if wheel was scrolled up,
  * and negative, if wheel was scrolled down.
  */
	if (delta)
		handle(delta);
}

function oldwheel(event){
        var delta = 0;
        if (!event) /* For IE. */
                event = window.event;
        if (event.wheelDelta) { /* IE/Opera. */
                delta = event.wheelDelta/120;
                /** In Opera 9, delta differs in sign as compared to IE.
                 */
                if (window.opera)
                        delta = -delta;
        } else if (event.detail) { /** Mozilla case. */
                /** In Mozilla, sign of delta is different than in IE.
                 * Also, delta is multiple of 3.
                 */
                delta = -event.detail/3;
        }
        /** If delta is nonzero, handle it.
         * Basically, delta is now positive if wheel was scrolled up,
         * and negative, if wheel was scrolled down.
         */
        if (delta)
                handle(delta);
        /** Prevent default actions caused by mouse wheel.
         * That might be ugly, but we handle scrolls somehow
         * anyway, so don't bother here..
         */
        if (event.preventDefault)
                event.preventDefault();
	event.returnValue = false;
}