// Copyright (c) 2005-2008 Thomas Fuchs (http://script.aculo.us, http://mir.aculo.us)
//           (c) 2005-2008 Sammi Williams (http://www.oriontransfer.co.nz, sammi@oriontransfer.co.nz)
//
// script.aculo.us is freely distributable under the terms of an MIT-style license.
// For details, see the script.aculo.us web site: http://script.aculo.us/

if (Object.isUndefined(Effect)) 
    throw ("dragdrop.js requires including script.aculo.us' effects.js library");

var Droppables = {
    drops: [],
    
    remove: function(element){
        this.drops = this.drops.reject(function(d){
            return d.element == $(element)
        });
    },
    
    add: function(element){
        element = $(element);
        var options = Object.extend({
            greedy: true,
            hoverclass: null,
            tree: false
        }, arguments[1] ||
        {});
        
        // cache containers
        if (options.containment) {
            options._containers = [];
            var containment = options.containment;
            if (Object.isArray(containment)) {
                containment.each(function(c){
                    options._containers.push($(c))
                });
            }
            else {
                options._containers.push($(containment));
            }
        }
        
        if (options.accept) 
            options.accept = [options.accept].flatten();
        
        Element.makePositioned(element); // fix IE
        options.element = element;
        
        this.drops.push(options);
    },
    
    findDeepestChild: function(drops){
        deepest = drops[0];
        
        for (i = 1; i < drops.length; ++i) 
            if (Element.isParent(drops[i].element, deepest.element)) 
                deepest = drops[i];
        
        return deepest;
    },
    
    isContained: function(element, drop){
        var containmentNode;
        if (drop.tree) {
            containmentNode = element.treeNode;
        }
        else {
            containmentNode = element.parentNode;
        }
        return drop._containers.detect(function(c){
            return containmentNode == c
        });
    },
    
    /*isAffected: function(point, element, drop) {
     return (
     (drop.element!=element) &&
     ((!drop._containers) ||
     this.isContained(element, drop)) &&
     ((!drop.accept) ||
     (Element.classNames(element).detect(
     function(v) { return drop.accept.include(v) } ) )) &&
     Position.within(drop.element, point[0], point[1]) );
     },*/
    /*isAffected: function(point, element, drop) {
     Position.prepare();
     return (
     (drop.element!=element) &&
     ((!drop._containers) ||
     this.isContained(element, drop)) &&
     ((!drop.accept) ||
     (Element.classNames(element).detect(
     function(v) { return drop.accept.include(v) } ) )) &&
     Position.withinIncludingScrolloffsets(drop.element, point[0], point[1]) );
     },*/
    getOffSetTop: function(el){
    
        var ot = el.offsetTop;
        
        while ((el = el.offsetParent) != null) {
            ot += el.offsetTop;
        }
        
        return ot;
        
    },
    isAffected: function(point, element){
 		var origLeft = element.positionedOffset().left;
		var origTop = element.positionedOffset().top;
		if(this.drops[0].reverse  && this.drops[0].reverse ==1 ){
		
	        if (getInternetExplorerVersion() > 1.0 && getInternetExplorerVersion() <= 7.0) {
	            var column = Math.round(origLeft / (this.drops[0].colWidth + 1));
	        }
	        else {
	            var column = Math.floor(origLeft / (this.drops[0].colWidth + 1.25));
	        }
			if (sessionuseraccess != 'V' || view != 'new_day_view') {
		        if (getInternetExplorerVersion() > 1.0 && getInternetExplorerVersion() <= 7.0) {
		            var row = Math.round(origTop / this.drops[0].dropHeight);
		        }
		        else {
		            var row = Math.round(origTop / this.drops[0].dropHeight);
		        }
			}
	        else {
	            row = 0;
	        }
        if (getInternetExplorerVersion() > 1.0 && getInternetExplorerVersion() <= 7.0 && column > 0) {
            column = column - 1;
        }
        var pos = (row * 24 * _time_duration_loop) + column;
		
	}else{
		 if (sessionuseraccess != 'V' || view != 'day_view') {
            if (getInternetExplorerVersion() > 1.0 && getInternetExplorerVersion() <= 7.0) {
                var column = Math.round((point[0] - this.drops[0].gridStartLeft) / this.drops[0].colWidth);
            }
            else {
                var column = Math.floor((point[0] - this.drops[0].gridStartLeft) / this.drops[0].colWidth);
            }
        }
        else {
            column = 0;
        }
        if (getInternetExplorerVersion() > 1.0 && getInternetExplorerVersion() <= 7.0) {
            var row = Math.round(origTop/ this.drops[0].dropHeight);
        }
        else {
            var row = Math.round(origTop / this.drops[0].dropHeight);
        }
        if (getInternetExplorerVersion() > 1.0 && getInternetExplorerVersion() <= 7.0 && column > 0) {
            column = column - 1;
        }
        row = row - 1;
//		alert("row--->"+row+"column--->"+column+"pos---->"+(column * 24 * _time_duration_loop) + row );
        var pos = (column * 24 * _time_duration_loop) + row;
	}
        
		return this.drops[pos + 1];
    },
    deactivate: function(drop){
        if (drop.hoverclass) 
            Element.removeClassName(drop.element, drop.hoverclass);
        this.last_active = null;
    },
    
    activate: function(drop){
        if (drop.hoverclass) 
            Element.addClassName(drop.element, drop.hoverclass);
        this.last_active = drop;
    },
    
    /* show: function(point, element) {
     if(!this.drops.length) return;
     var drop, affected = [];
     this.drops.each( function(drop) {
     if(Droppables.isAffected(point, element, drop))
     affected.push(drop);
     });
     if(affected.length>0)
     drop = Droppables.findDeepestChild(affected);
     if(this.last_active && this.last_active != drop) this.deactivate(this.last_active);
     if (drop) {
     Position.within(drop.element, point[0], point[1]);
     if(drop.onHover)
     drop.onHover(element, drop.element, Position.overlap(drop.overlap, drop.element));
     if (drop != this.last_active) Droppables.activate(drop);
     }
     },*/
    show: function(point, element){
        if (!this.drops.length) 
            return;
        if (this.last_active) 
            this.deactivate(this.last_active);
        // Don't loop, call isAffected
        // isAffected will return the id of the element being dropped on
        // if null, we couldn't find it
        var drop = Droppables.isAffected(point, element);
        if (drop != null) {
            if (drop.onHover) 
                drop.onHover(element, drop.element, Position.overlap(drop.overlap, drop.element));
            if (drop.greedy) {
                Droppables.activate(drop);
                //throw $break;
            }
        }
        else {
            return false;
        }
    },
    
    fire: function(event, element){
        if (!this.last_active) 
            return;
        Position.prepare();
        if (this.isAffected([Event.pointerX(event), Event.pointerY(event)], element, this.last_active)) 
            if (this.last_active.onDrop) {
                this.last_active.onDrop(element, this.last_active.element, event);
                return true;
            }
    },
    
    reset: function(){
        if (this.last_active) 
            this.deactivate(this.last_active);
    }
};

var Draggables = {
    drags: [],
    observers: [],
    
    register: function(draggable){
        if (this.drags.length == 0) {
            this.eventMouseUp = this.endDrag.bindAsEventListener(this);
            this.eventMouseMove = this.updateDrag.bindAsEventListener(this);
            this.eventKeypress = this.keyPress.bindAsEventListener(this);
            
            Event.observe(document, "mouseup", this.eventMouseUp);
            Event.observe(document, "mousemove", this.eventMouseMove);
            Event.observe(document, "keypress", this.eventKeypress);
        }
        this.drags.push(draggable);
    },
    
    unregister: function(draggable){
        this.drags = this.drags.reject(function(d){
            return d == draggable
        });
        if (this.drags.length == 0) {
            Event.stopObserving(document, "mouseup", this.eventMouseUp);
            Event.stopObserving(document, "mousemove", this.eventMouseMove);
            Event.stopObserving(document, "keypress", this.eventKeypress);
        }
    },
    
    activate: function(draggable){
        if (draggable.options.delay) {
            this._timeout = setTimeout(function(){
                Draggables._timeout = null;
                window.focus();
                Draggables.activeDraggable = draggable;
            }
.bind(this), draggable.options.delay);
        }
        else {
            window.focus(); // allows keypress events if window isn't currently focused, fails for Safari
            this.activeDraggable = draggable;
        }
    },
    
    deactivate: function(){
        this.activeDraggable = null;
    },
    
    updateDrag: function(event){
        if (!this.activeDraggable) 
            return;
        var pointer = [Event.pointerX(event), Event.pointerY(event)];
        // Mozilla-based browsers fire successive mousemove events with
        // the same coordinates, prevent needless redrawing (moz bug?)
        if (this._lastPointer && (this._lastPointer.inspect() == pointer.inspect())) 
            return;
        this._lastPointer = pointer;
        
        this.activeDraggable.updateDrag(event, pointer);
    },
    
    endDrag: function(event){
        if (this._timeout) {
            clearTimeout(this._timeout);
            this._timeout = null;
        }
        if (!this.activeDraggable) 
            return;
        this._lastPointer = null;
        this.activeDraggable.endDrag(event);
        this.activeDraggable = null;
    },
    
    keyPress: function(event){
        if (this.activeDraggable) 
            this.activeDraggable.keyPress(event);
    },
    
    addObserver: function(observer){
        this.observers.push(observer);
        this._cacheObserverCallbacks();
    },
    
    removeObserver: function(element){ // element instead of observer fixes mem leaks
        this.observers = this.observers.reject(function(o){
            return o.element == element
        });
        this._cacheObserverCallbacks();
    },
    
    notify: function(eventName, draggable, event){ // 'onStart', 'onEnd', 'onDrag'
        if (this[eventName + 'Count'] > 0) 
            this.observers.each(function(o){
                if (o[eventName]) 
                    o[eventName](eventName, draggable, event);
            });
        if (draggable.options[eventName]) 
            draggable.options[eventName](draggable, event);
    },
    
    _cacheObserverCallbacks: function(){
        ['onStart', 'onEnd', 'onDrag'].each(function(eventName){
            Draggables[eventName + 'Count'] = Draggables.observers.select(function(o){
                return o[eventName];
            }).length;
        });
    }
};

/*--------------------------------------------------------------------------*/

var Draggable = Class.create({
    initialize: function(element){
        var defaults = {
            handle: false,
            reverteffect: function(element, top_offset, left_offset){
                var dur = Math.sqrt(Math.abs(top_offset ^ 2) + Math.abs(left_offset ^ 2)) * 0.02;
                new Effect.Move(element, {
                    x: -left_offset,
                    y: -top_offset,
                    duration: dur,
                    queue: {
                        scope: '_draggable',
                        position: 'end'
                    }
                });
            },
            endeffect: function(element){
                var toOpacity = Object.isNumber(element._opacity) ? element._opacity : 1.0;
                new Effect.Opacity(element, {
                    duration: 0.2,
                    from: 0.7,
                    to: toOpacity,
                    queue: {
                        scope: '_draggable',
                        position: 'end'
                    },
                    afterFinish: function(){
                        Draggable._dragging[element] = false
                    }
                });
            },
            zindex: 1000,
            revert: false,
            quiet: false,
            scroll: false,
            scrollSensitivity: 20,
            scrollSpeed: 15,
            snap: false, // false, or xy or [x,y] or function(x,y){ return [x,y] }
            delay: 0
        };
        
        if (!arguments[1] || Object.isUndefined(arguments[1].endeffect)) 
            Object.extend(defaults, {
                starteffect: function(element){
                    element._opacity = Element.getOpacity(element);
                    Draggable._dragging[element] = true;
                    new Effect.Opacity(element, {
                        duration: 0.2,
                        from: element._opacity,
                        to: 0.7
                    });
                }
            });
        
        var options = Object.extend(defaults, arguments[1] ||
        {});
        
        this.element = $(element);
        
        if (options.handle && Object.isString(options.handle)) 
            this.handle = this.element.down('.' + options.handle, 0);
        
        if (!this.handle) 
            this.handle = $(options.handle);
        if (!this.handle) 
            this.handle = this.element;
        
        if (options.scroll && !options.scroll.scrollTo && !options.scroll.outerHTML) {
            options.scroll = $(options.scroll);
            this._isScrollChild = Element.childOf(this.element, options.scroll);
        }
        
        Element.makePositioned(this.element); // fix IE
        this.options = options;
        this.dragging = false;
        
        this.eventMouseDown = this.initDrag.bindAsEventListener(this);
        Event.observe(this.handle, "mousedown", this.eventMouseDown);
        
        Draggables.register(this);
    },
    
    destroy: function(){
        Event.stopObserving(this.handle, "mousedown", this.eventMouseDown);
        Draggables.unregister(this);
    },
    
    currentDelta: function(){
        return ([parseInt(Element.getStyle(this.element, 'left') || '0'), parseInt(Element.getStyle(this.element, 'top') || '0')]);
    },
    
    initDrag: function(event){
        if (!Object.isUndefined(Draggable._dragging[this.element]) &&
        Draggable._dragging[this.element]) 
            return;
        if (Event.isLeftClick(event)) {
            // abort on form elements, fixes a Firefox issue
            var src = Event.element(event);
            if ((tag_name = src.tagName.toUpperCase()) &&
            (tag_name == 'INPUT' ||
            tag_name == 'SELECT' ||
            tag_name == 'OPTION' ||
            tag_name == 'BUTTON' ||
            tag_name == 'TEXTAREA')) 
                return;
            
            var pointer = [Event.pointerX(event), Event.pointerY(event)];
            var pos = Position.cumulativeOffset(this.element);
            this.offset = [0, 1].map(function(i){
                return (pointer[i] - pos[i])
            });
            
            Draggables.activate(this);
            Event.stop(event);
        }
    },
    
    startDrag: function(event){
        this.dragging = true;
        if (!this.delta) 
            this.delta = this.currentDelta();
        
        if (this.options.zindex) {
            this.originalZ = parseInt(Element.getStyle(this.element, 'z-index') || 0);
            this.element.style.zIndex = this.options.zindex;
        }
        
        if (this.options.ghosting) {
            this._clone = this.element.cloneNode(true);
            this._originallyAbsolute = (this.element.getStyle('position') == 'absolute');
            if (!this._originallyAbsolute) 
                Position.absolutize(this.element);
            this.element.parentNode.insertBefore(this._clone, this.element);
        }
        
        if (this.options.scroll) {
            if (this.options.scroll == window) {
                var where = this._getWindowScroll(this.options.scroll);
                this.originalScrollLeft = where.left;
                this.originalScrollTop = where.top;
            }
            else {
                this.originalScrollLeft = this.options.scroll.scrollLeft;
                this.originalScrollTop = this.options.scroll.scrollTop;
            }
        }
        
        Draggables.notify('onStart', this, event);
        
        if (this.options.starteffect) 
            this.options.starteffect(this.element);
    },
    
    updateDrag: function(event, pointer){
        if (!this.dragging) 
            this.startDrag(event);
        
        if (!this.options.quiet) {
            Position.prepare();
            // --Abhishek (Show draggable pointer as yellow)
            Droppables.show(pointer, this.element);
        }
        
        Draggables.notify('onDrag', this, event);
        
        this.draw(pointer);
        if (this.options.change) 
            this.options.change(this);
        
        if (this.options.scroll) {
            this.stopScrolling();
            
            var p;
            if (this.options.scroll == window) {
                with (this._getWindowScroll(this.options.scroll)) {
                    p = [left, top, left + width, top + height];
                }
            }
            else {
                p = Position.page(this.options.scroll);
                p[0] += this.options.scroll.scrollLeft + Position.deltaX;
                p[1] += this.options.scroll.scrollTop + Position.deltaY;
                p.push(p[0] + this.options.scroll.offsetWidth);
                p.push(p[1] + this.options.scroll.offsetHeight);
            }
            var speed = [0, 0];
            if (pointer[0] < (p[0] + this.options.scrollSensitivity)) 
                speed[0] = pointer[0] - (p[0] + this.options.scrollSensitivity);
            if (pointer[1] < (p[1] + this.options.scrollSensitivity)) 
                speed[1] = pointer[1] - (p[1] + this.options.scrollSensitivity);
            if (pointer[0] > (p[2] - this.options.scrollSensitivity)) 
                speed[0] = pointer[0] - (p[2] - this.options.scrollSensitivity);
            if (pointer[1] > (p[3] - this.options.scrollSensitivity)) 
                speed[1] = pointer[1] - (p[3] - this.options.scrollSensitivity);
            this.startScrolling(speed);
        }
        
        // fix AppleWebKit rendering
        if (Prototype.Browser.WebKit) 
            window.scrollBy(0, 0);
        
        Event.stop(event);
    },
    
    finishDrag: function(event, success){
        this.dragging = false;
        if (this.options.quiet) {
            Position.prepare();
            var pointer = [Event.pointerX(event), Event.pointerY(event)];
            Droppables.show(pointer, this.element);
        }
        
        if (this.options.ghosting) {
            if (!this._originallyAbsolute) 
                Position.relativize(this.element);
            delete this._originallyAbsolute;
            Element.remove(this._clone);
            this._clone = null;
        }
        if (Droppables.last_active && !check_for_end_time(Droppables.last_active.element.id, this.element.id)){
			success = false;
			} 
        var dropped = false;
        if (success) {
            dropped = Droppables.fire(event, this.element);
            if (!dropped) 
                dropped = false;
        }
        if (dropped && this.options.onDropped) 
            this.options.onDropped(this.element);
        Draggables.notify('onEnd', this, event);
        
        var revert = this.options.revert;
        if (revert && Object.isFunction(revert)) 
            revert = revert(this.element);
        
        var d = this.currentDelta();
        if (revert && this.options.reverteffect) {
            if (dropped == 0 || revert != 'failure') 
                this.options.reverteffect(this.element, d[1] - this.delta[1], d[0] - this.delta[0]);
        }
        else {
            this.delta = d;
        }
        
        if (this.options.zindex) 
            this.element.style.zIndex = this.originalZ;
        
        if (this.options.endeffect) 
            this.options.endeffect(this.element);
        
        Draggables.deactivate(this);
        Droppables.reset();
    },
    
    keyPress: function(event){
        if (event.keyCode != Event.KEY_ESC) 
            return;
        this.finishDrag(event, false);
        Event.stop(event);
    },
    
    endDrag: function(event){
        if (!this.dragging) 
            return;
        this.stopScrolling();
        this.finishDrag(event, true);
        Event.stop(event);
    },
    
    draw: function(point){
        var pos = Position.cumulativeOffset(this.element);
        if (this.options.ghosting) {
            var r = Position.realOffset(this.element);
            pos[0] += r[0] - Position.deltaX;
            pos[1] += r[1] - Position.deltaY;
        }
        
        var d = this.currentDelta();
        pos[0] -= d[0];
        pos[1] -= d[1];
        
        if (this.options.scroll && (this.options.scroll != window && this._isScrollChild)) {
            pos[0] -= this.options.scroll.scrollLeft - this.originalScrollLeft;
            pos[1] -= this.options.scroll.scrollTop - this.originalScrollTop;
        }
        
        var p = [0, 1].map(function(i){
            return (point[i] - pos[i] - this.offset[i])
        }
.bind(this));
        
        if (this.options.snap) {
            if (Object.isFunction(this.options.snap)) {
                p = this.options.snap(p[0], p[1], this);
            }
            else {
                if (Object.isArray(this.options.snap)) {
                    p = p.map(function(v, i){
                        return (v / this.options.snap[i]).round() * this.options.snap[i]
                    }
.bind(this));
                }
                else {
                    p = p.map(function(v){
                        return (v / this.options.snap).round() * this.options.snap
                    }
.bind(this));
                }
            }
        }
        
        var style = this.element.style;
        if ((!this.options.constraint) || (this.options.constraint == 'horizontal')) 
            style.left = p[0] + "px";
        if ((!this.options.constraint) || (this.options.constraint == 'vertical')) 
            style.top = p[1] + "px";
        
        if (style.visibility == "hidden") 
            style.visibility = ""; // fix gecko rendering
    },
    
    stopScrolling: function(){
        if (this.scrollInterval) {
            clearInterval(this.scrollInterval);
            this.scrollInterval = null;
            Draggables._lastScrollPointer = null;
        }
    },
    
    startScrolling: function(speed){
        if (!(speed[0] || speed[1])) 
            return;
        this.scrollSpeed = [speed[0] * this.options.scrollSpeed, speed[1] * this.options.scrollSpeed];
        this.lastScrolled = new Date();
        this.scrollInterval = setInterval(this.scroll.bind(this), 10);
    },
    
    scroll: function(){
        var current = new Date();
        var delta = current - this.lastScrolled;
        this.lastScrolled = current;
        if (this.options.scroll == window) {
            with (this._getWindowScroll(this.options.scroll)) {
                if (this.scrollSpeed[0] || this.scrollSpeed[1]) {
                    var d = delta / 1000;
                    this.options.scroll.scrollTo(left + d * this.scrollSpeed[0], top + d * this.scrollSpeed[1]);
                }
            }
        }
        else {
            this.options.scroll.scrollLeft += this.scrollSpeed[0] * delta / 1000;
            this.options.scroll.scrollTop += this.scrollSpeed[1] * delta / 1000;
        }
        
        Position.prepare();
        Droppables.show(Draggables._lastPointer, this.element);
        Draggables.notify('onDrag', this);
        if (this._isScrollChild) {
            Draggables._lastScrollPointer = Draggables._lastScrollPointer || $A(Draggables._lastPointer);
            Draggables._lastScrollPointer[0] += this.scrollSpeed[0] * delta / 1000;
            Draggables._lastScrollPointer[1] += this.scrollSpeed[1] * delta / 1000;
            if (Draggables._lastScrollPointer[0] < 0) 
                Draggables._lastScrollPointer[0] = 0;
            if (Draggables._lastScrollPointer[1] < 0) 
                Draggables._lastScrollPointer[1] = 0;
            this.draw(Draggables._lastScrollPointer);
        }
        
        if (this.options.change) 
            this.options.change(this);
    },
    
    _getWindowScroll: function(w){
        var T, L, W, H;
        with (w.document) {
            if (w.document.documentElement && documentElement.scrollTop) {
                T = documentElement.scrollTop;
                L = documentElement.scrollLeft;
            }
            else 
                if (w.document.body) {
                    T = body.scrollTop;
                    L = body.scrollLeft;
                }
            if (w.innerWidth) {
                W = w.innerWidth;
                H = w.innerHeight;
            }
            else 
                if (w.document.documentElement && documentElement.clientWidth) {
                    W = documentElement.clientWidth;
                    H = documentElement.clientHeight;
                }
                else {
                    W = body.offsetWidth;
                    H = body.offsetHeight;
                }
        }
        return {
            top: T,
            left: L,
            width: W,
            height: H
        };
    }
});

Draggable._dragging = {};

/*--------------------------------------------------------------------------*/

var SortableObserver = Class.create({
    initialize: function(element, observer){
        this.element = $(element);
        this.observer = observer;
        this.lastValue = Sortable.serialize(this.element);
    },
    
    onStart: function(){
        this.lastValue = Sortable.serialize(this.element);
    },
    
    onEnd: function(){
        Sortable.unmark();
        if (this.lastValue != Sortable.serialize(this.element)) 
            this.observer(this.element)
    }
});

var Sortable = {
    SERIALIZE_RULE: /^[^_\-](?:[A-Za-z0-9\-\_]*)[_](.*)$/,
    
    sortables: {},
    
    _findRootElement: function(element){
        while (element.tagName.toUpperCase() != "BODY") {
            if (element.id && Sortable.sortables[element.id]) 
                return element;
            element = element.parentNode;
        }
    },
    
    options: function(element){
        element = Sortable._findRootElement($(element));
        if (!element) 
            return;
        return Sortable.sortables[element.id];
    },
    
    destroy: function(element){
        element = $(element);
        var s = Sortable.sortables[element.id];
        
        if (s) {
            Draggables.removeObserver(s.element);
            s.droppables.each(function(d){
                Droppables.remove(d)
            });
            s.draggables.invoke('destroy');
            
            delete Sortable.sortables[s.element.id];
        }
    },
    
    create: function(element){
        element = $(element);
        var options = Object.extend({
            element: element,
            tag: 'li', // assumes li children, override with tag: 'tagname'
            dropOnEmpty: false,
            tree: false,
            treeTag: 'ul',
            overlap: 'vertical', // one of 'vertical', 'horizontal'
            constraint: 'vertical', // one of 'vertical', 'horizontal', false
            containment: element, // also takes array of elements (or id's); or false
            handle: false, // or a CSS class
            only: false,
            delay: 0,
            hoverclass: null,
            ghosting: false,
            quiet: false,
            scroll: false,
            scrollSensitivity: 20,
            scrollSpeed: 15,
            format: this.SERIALIZE_RULE,
            
            // these take arrays of elements or ids and can be
            // used for better initialization performance
            elements: false,
            handles: false,
            
            onChange: Prototype.emptyFunction,
            onUpdate: Prototype.emptyFunction
        }, arguments[1] ||
        {});
        
        // clear any old sortable with same element
        this.destroy(element);
        
        // build options for the draggables
        var options_for_draggable = {
            revert: true,
            quiet: options.quiet,
            scroll: options.scroll,
            scrollSpeed: options.scrollSpeed,
            scrollSensitivity: options.scrollSensitivity,
            delay: options.delay,
            ghosting: options.ghosting,
            constraint: options.constraint,
            handle: options.handle
        };
        
        if (options.starteffect) 
            options_for_draggable.starteffect = options.starteffect;
        
        if (options.reverteffect) 
            options_for_draggable.reverteffect = options.reverteffect;
        else 
            if (options.ghosting) 
                options_for_draggable.reverteffect = function(element){
                    element.style.top = 0;
                    element.style.left = 0;
                };
        
        if (options.endeffect) 
            options_for_draggable.endeffect = options.endeffect;
        
        if (options.zindex) 
            options_for_draggable.zindex = options.zindex;
        
        // build options for the droppables
        var options_for_droppable = {
            overlap: options.overlap,
            containment: options.containment,
            tree: options.tree,
            hoverclass: options.hoverclass,
            onHover: Sortable.onHover
        };
        
        var options_for_tree = {
            onHover: Sortable.onEmptyHover,
            overlap: options.overlap,
            containment: options.containment,
            hoverclass: options.hoverclass
        };
        
        // fix for gecko engine
        Element.cleanWhitespace(element);
        
        options.draggables = [];
        options.droppables = [];
        
        // drop on empty handling
        if (options.dropOnEmpty || options.tree) {
            Droppables.add(element, options_for_tree);
            options.droppables.push(element);
        }
        
        (options.elements || this.findElements(element, options) || []).each(function(e, i){
            var handle = options.handles ? $(options.handles[i]) : (options.handle ? $(e).select('.' + options.handle)[0] : e);
            options.draggables.push(new Draggable(e, Object.extend(options_for_draggable, {
                handle: handle
            })));
            Droppables.add(e, options_for_droppable);
            if (options.tree) 
                e.treeNode = element;
            options.droppables.push(e);
        });
        
        if (options.tree) {
            (Sortable.findTreeElements(element, options) || []).each(function(e){
                Droppables.add(e, options_for_tree);
                e.treeNode = element;
                options.droppables.push(e);
            });
        }
        
        // keep reference
        this.sortables[element.id] = options;
        
        // for onupdate
        Draggables.addObserver(new SortableObserver(element, options.onUpdate));
        
    },
    
    // return all suitable-for-sortable elements in a guaranteed order
    findElements: function(element, options){
        return Element.findChildren(element, options.only, options.tree ? true : false, options.tag);
    },
    
    findTreeElements: function(element, options){
        return Element.findChildren(element, options.only, options.tree ? true : false, options.treeTag);
    },
    
    onHover: function(element, dropon, overlap){
        if (Element.isParent(dropon, element)) 
            return;
        
        if (overlap > .33 && overlap < .66 && Sortable.options(dropon).tree) {
            return;
        }
        else 
            if (overlap > 0.5) {
                Sortable.mark(dropon, 'before');
                if (dropon.previousSibling != element) {
                    var oldParentNode = element.parentNode;
                    element.style.visibility = "hidden"; // fix gecko rendering
                    dropon.parentNode.insertBefore(element, dropon);
                    if (dropon.parentNode != oldParentNode) 
                        Sortable.options(oldParentNode).onChange(element);
                    Sortable.options(dropon.parentNode).onChange(element);
                }
            }
            else {
                Sortable.mark(dropon, 'after');
                var nextElement = dropon.nextSibling || null;
                if (nextElement != element) {
                    var oldParentNode = element.parentNode;
                    element.style.visibility = "hidden"; // fix gecko rendering
                    dropon.parentNode.insertBefore(element, nextElement);
                    if (dropon.parentNode != oldParentNode) 
                        Sortable.options(oldParentNode).onChange(element);
                    Sortable.options(dropon.parentNode).onChange(element);
                }
            }
    },
    
    onEmptyHover: function(element, dropon, overlap){
        var oldParentNode = element.parentNode;
        var droponOptions = Sortable.options(dropon);
        
        if (!Element.isParent(dropon, element)) {
            var index;
            
            var children = Sortable.findElements(dropon, {
                tag: droponOptions.tag,
                only: droponOptions.only
            });
            var child = null;
            
            if (children) {
                var offset = Element.offsetSize(dropon, droponOptions.overlap) * (1.0 - overlap);
                
                for (index = 0; index < children.length; index += 1) {
                    if (offset - Element.offsetSize(children[index], droponOptions.overlap) >= 0) {
                        offset -= Element.offsetSize(children[index], droponOptions.overlap);
                    }
                    else 
                        if (offset - (Element.offsetSize(children[index], droponOptions.overlap) / 2) >= 0) {
                            child = index + 1 < children.length ? children[index + 1] : null;
                            break;
                        }
                        else {
                            child = children[index];
                            break;
                        }
                }
            }
            
            dropon.insertBefore(element, child);
            
            Sortable.options(oldParentNode).onChange(element);
            droponOptions.onChange(element);
        }
    },
    
    unmark: function(){
        if (Sortable._marker) 
            Sortable._marker.hide();
    },
    
    mark: function(dropon, position){
        // mark on ghosting only
        var sortable = Sortable.options(dropon.parentNode);
        if (sortable && !sortable.ghosting) 
            return;
        
        if (!Sortable._marker) {
            Sortable._marker = ($('dropmarker') || Element.extend(document.createElement('DIV'))).hide().addClassName('dropmarker').setStyle({
                position: 'absolute'
            });
            document.getElementsByTagName("body").item(0).appendChild(Sortable._marker);
        }
        var offsets = Position.cumulativeOffset(dropon);
        Sortable._marker.setStyle({
            left: offsets[0] + 'px',
            top: offsets[1] + 'px'
        });
        
        if (position == 'after') 
            if (sortable.overlap == 'horizontal') 
                Sortable._marker.setStyle({
                    left: (offsets[0] + dropon.clientWidth) + 'px'
                });
            else 
                Sortable._marker.setStyle({
                    top: (offsets[1] + dropon.clientHeight) + 'px'
                });
        
        Sortable._marker.show();
    },
    
    _tree: function(element, options, parent){
        var children = Sortable.findElements(element, options) || [];
        
        for (var i = 0; i < children.length; ++i) {
            var match = children[i].id.match(options.format);
            
            if (!match) 
                continue;
            
            var child = {
                id: encodeURIComponent(match ? match[1] : null),
                element: element,
                parent: parent,
                children: [],
                position: parent.children.length,
                container: $(children[i]).down(options.treeTag)
            };
            
            /* Get the element containing the children and recurse over it */
            if (child.container) 
                this._tree(child.container, options, child);
            
            parent.children.push(child);
        }
        
        return parent;
    },
    
    tree: function(element){
        element = $(element);
        var sortableOptions = this.options(element);
        var options = Object.extend({
            tag: sortableOptions.tag,
            treeTag: sortableOptions.treeTag,
            only: sortableOptions.only,
            name: element.id,
            format: sortableOptions.format
        }, arguments[1] ||
        {});
        
        var root = {
            id: null,
            parent: null,
            children: [],
            container: element,
            position: 0
        };
        
        return Sortable._tree(element, options, root);
    },
    
    /* Construct a [i] index for a particular node */
    _constructIndex: function(node){
        var index = '';
        do {
            if (node.id) 
                index = '[' + node.position + ']' + index;
        }
        while ((node = node.parent) != null);
        return index;
    },
    
    sequence: function(element){
        element = $(element);
        var options = Object.extend(this.options(element), arguments[1] ||
        {});
        
        return $(this.findElements(element, options) || []).map(function(item){
            return item.id.match(options.format) ? item.id.match(options.format)[1] : '';
        });
    },
    
    setSequence: function(element, new_sequence){
        element = $(element);
        var options = Object.extend(this.options(element), arguments[2] ||
        {});
        
        var nodeMap = {};
        this.findElements(element, options).each(function(n){
            if (n.id.match(options.format)) 
                nodeMap[n.id.match(options.format)[1]] = [n, n.parentNode];
            n.parentNode.removeChild(n);
        });
        
        new_sequence.each(function(ident){
            var n = nodeMap[ident];
            if (n) {
                n[1].appendChild(n[0]);
                delete nodeMap[ident];
            }
        });
    },
    
    serialize: function(element){
        element = $(element);
        var options = Object.extend(Sortable.options(element), arguments[1] ||
        {});
        var name = encodeURIComponent((arguments[1] && arguments[1].name) ? arguments[1].name : element.id);
        
        if (options.tree) {
            return Sortable.tree(element, arguments[1]).children.map(function(item){
                return [name + Sortable._constructIndex(item) + "[id]=" +
                encodeURIComponent(item.id)].concat(item.children.map(arguments.callee));
            }).flatten().join('&');
        }
        else {
            return Sortable.sequence(element, arguments[1]).map(function(item){
                return name + "[]=" + encodeURIComponent(item);
            }).join('&');
        }
    }
};

// Returns true if child is contained within element
Element.isParent = function(child, element){
    if (!child.parentNode || child == element) 
        return false;
    if (child.parentNode == element) 
        return true;
    return Element.isParent(child.parentNode, element);
};

Element.findChildren = function(element, only, recursive, tagName){
    if (!element.hasChildNodes()) 
        return null;
    tagName = tagName.toUpperCase();
    if (only) 
        only = [only].flatten();
    var elements = [];
    $A(element.childNodes).each(function(e){
        if (e.tagName && e.tagName.toUpperCase() == tagName &&
        (!only || (Element.classNames(e).detect(function(v){
            return only.include(v)
        })))) 
            elements.push(e);
        if (recursive) {
            var grandchildren = Element.findChildren(e, only, recursive, tagName);
            if (grandchildren) 
                elements.push(grandchildren);
        }
    });
    
    return (elements.length > 0 ? elements.flatten() : []);
};

Element.offsetSize = function(element, type){
    return element['offset' + ((type == 'vertical' || type == 'height') ? 'Height' : 'Width')];
};