// script.aculo.us dragdrop.js v1.7.1_beta3, Fri May 25 17:19:41 +0200 2007

// Copyright (c) 2005-2007 Thomas Fuchs (http://script.aculo.us, http://mir.aculo.us)
// (c) 2005-2007 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(typeof Effect == 'undefined')
 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((typeof containment == 'object') &&
 (containment.constructor == Array)) {
 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]) );
 },

 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 affected = [];

 if(this.last_active) this.deactivate(this.last_active);
 this.drops.each( function(drop) {
 if(Droppables.isAffected(point, element, drop))
 affected.push(drop);
 });

 if(affected.length>0) {
 drop = Droppables.findDeepestChild(affected);
 Position.within(drop.element, point[0], point[1]);
 if(drop.onHover)
 drop.onHover(element, drop.element, Position.overlap(drop.overlap, drop.element));

 Droppables.activate(drop);
 }
 },

 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(draggable.element, "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(draggable.element, "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();
Draggable._dragging = {};

Draggable.prototype = {
 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 = typeof element._opacity == 'number' ? 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] || typeof arguments[1].endeffect == 'undefined')
 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 && (typeof options.handle == 'string'))
 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.delta = this.currentDelta();
 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(typeof Draggable._dragging[this.element] != 'undefined' &&
 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.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);
 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();
 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) {
 Position.relativize(this.element);
 Element.remove(this._clone);
 this._clone = null;
 }

 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 && typeof revert == 'function') 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(typeof this.options.snap == 'function') {
 p = this.options.snap(p[0],p[1],this);
 } else {
 if(this.options.snap instanceof Array) {
 p = p.map( function(v, i) {
 return Math.round(v/this.options.snap[i])*this.options.snap[i] }.bind(this))
 } else {
 p = p.map( function(v) {
 return Math.round(v/this.options.snap)*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 };
 }
}

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

var SortableObserver = Class.create();
SortableObserver.prototype = {
 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){
 var s = Sortable.options(element);

 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).getElementsByClassName(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')];
}