//MooTools More, <http://mootools.net/more>. Copyright (c) 2006-2008 Valerio Proietti, <http://mad4milk.net>, MIT Style License.

/*
Script: Fx.Scroll.js
	Effect to smoothly scroll any element, including the window.

License:
	MIT-style license.
*/

Fx.Scroll = new Class({

	Extends: Fx,

	options: {
		offset: {'x': 0, 'y': 0},
		wheelStops: true
	},

	initialize: function(element, options){
		this.element = this.subject = $(element);
		this.parent(options);
		var cancel = this.cancel.bind(this, false);

		if ($type(this.element) != 'element') this.element = $(this.element.getDocument().body);

		var stopper = this.element;

		if (this.options.wheelStops){
			this.addEvent('start', function(){
				stopper.addEvent('mousewheel', cancel);
			}, true);
			this.addEvent('complete', function(){
				stopper.removeEvent('mousewheel', cancel);
			}, true);
		}
	},

	set: function(){
		var now = Array.flatten(arguments);
		this.element.scrollTo(now[0], now[1]);
	},

	compute: function(from, to, delta){
		var now = [];
		var x = 2;
		x.times(function(i){
			now.push(Fx.compute(from[i], to[i], delta));
		});
		return now;
	},

	start: function(x, y){
		if (!this.check(arguments.callee, x, y)) return this;
		var offsetSize = this.element.getSize(), scrollSize = this.element.getScrollSize();
		var scroll = this.element.getScroll(), values = {x: x, y: y};
		for (var z in values){
			var max = scrollSize[z] - offsetSize[z];
			if ($chk(values[z])) values[z] = ($type(values[z]) == 'number') ? values[z].limit(0, max) : max;
			else values[z] = scroll[z];
			values[z] += this.options.offset[z];
		}
		return this.parent([scroll.x, scroll.y], [values.x, values.y]);
	},

	toTop: function(){
		return this.start(false, 0);
	},

	toLeft: function(){
		return this.start(0, false);
	},

	toRight: function(){
		return this.start('right', false);
	},

	toBottom: function(){
		return this.start(false, 'bottom');
	},

	toElement: function(el){
		var position = $(el).getPosition(this.element);
		return this.start(position.x, position.y);
	}

});

/* 
Besondere Klasse für Srcoll.toElement, die auch im IE optimal funktioniert
	  A workaround for IE issues in mootools 1.2.1
 * - Recreates FX.Scroll() but utilises 1.2.0's getPosition/getOffset routines.
http://www.mooforum.net/help12/scroll-scroll-element-then-back-t814.html
*/
Fx.Scroll2 = new Class({
 
    'Extends': Fx.Scroll,
 
    'styleString': Element.getComputedStyle,
    'styleNumber': function(element, style) {
        return this.styleString(element, style).toInt() || 0;
    },
    'borderBox': function(element) {
        return this.styleString(element, '-moz-box-sizing') == 'border-box';
    },
    'topBorder': function(element) {
        return this.styleNumber(element, 'border-top-width');
    },
    'leftBorder': function(element) {
        return this.styleNumber(element, 'border-left-width');
    },
    'isBody': function(element) {
        return (/^(?:body|html)$/i).test(element.tagName);
    },  
    'toElement': function(el) {
        var offset   = {x: 0, y: 0};
        var element  = $(el);
        
        if (this.isBody(element)) {
            return offset;
        }
        var scroll = element.getScrolls();
                
        while (element && !this.isBody(element)){
            offset.x += element.offsetLeft;
            offset.y += element.offsetTop;
            
            if (Browser.Engine.gecko){
                if (!this.borderBox(element)){
                    offset.x += this.leftBorder(element);
                    offset.y += this.topBorder(element);
                }
                var parent = element.parentNode;
                if (parent && this.styleString(parent, 'overflow') != 'visible'){
                    offset.x += this.leftBorder(parent);
                    offset.y += this.topBorder(parent);
                }
            } else if (Browser.Engine.trident || Browser.Engine.webkit){
                offset.x += this.leftBorder(element);
                offset.y += this.topBorder(element);
            }
 
            element = element.offsetParent;
            if (Browser.Engine.trident) {
                while (element && !element.currentStyle.hasLayout) {
                    element = element.offsetParent;
                }
            }
        }
        if (Browser.Engine.gecko && !this.borderBox(element)){
            offset.x -= this.leftBorder(element);
            offset.y -= this.topBorder(element);
        }
        
        var relative = this.element;
        var relativePosition = (relative && (relative = $(relative))) ? relative.getPosition() : {x: 0, y: 0};
        var position = {x: offset.x - scroll.x, y: offset.y - scroll.y};
        
        return this.start(position.x - relativePosition.x, position.y - relativePosition.y);
    }
});