jquery-ui/ui/jquery.ui.sortable.js

/*!
 * jQuery UI Sortable @VERSION
 * http://jqueryui.com
 *
 * Copyright 2013 jQuery Foundation and other contributors
 * Released under the MIT license.
 * http://jquery.org/license
 *
 * http://api.jqueryui.com/sortable/
 *
 * Depends:
 *	jquery.ui.core.js
 *	jquery.ui.mouse.js
 *	jquery.ui.widget.js
 */
(function( $, undefined ) {

/*jshint loopfunc: true */

function isOverAxis( x, reference, size ) {
	return ( x > reference ) && ( x < ( reference + size ) );
}

function isFloating(item) {
	return (/left|right/).test(item.css("float")) || (/inline|table-cell/).test(item.css("display"));
}

$.widget("ui.sortable", $.ui.mouse, {
	version: "@VERSION",
	widgetEventPrefix: "sort",
	ready: false,
	options: {
		appendTo: "parent",
		axis: false,
		connectWith: false,
		containment: false,
		cursor: "auto",
		cursorAt: false,
		dropOnEmpty: true,
		forcePlaceholderSize: false,
		forceHelperSize: false,
		grid: false,
		handle: false,
		helper: "original",
		items: "> *",
		opacity: false,
		placeholder: false,
		revert: false,
		scroll: true,
		scrollSensitivity: 20,
		scrollSpeed: 20,
		scope: "default",
		tolerance: "intersect",
		zIndex: 1000,

		// callbacks
		activate: null,
		beforeStop: null,
		change: null,
		deactivate: null,
		out: null,
		over: null,
		receive: null,
		remove: null,
		sort: null,
		start: null,
		stop: null,
		update: null
	},
	_create: function() {

		var o = this.options;
		this.containerCache = {};
		this.element.addClass("ui-sortable");

		//Get the items
		this.refresh();

		//Let's determine if the items are being displayed horizontally
		this.floating = this.items.length ? o.axis === "x" || isFloating(this.items[0].item) : false;

		//Let's determine the parent's offset
		this.offset = this.element.offset();

		//Initialize mouse events for interaction
		this._mouseInit();

		//We're ready to go
		this.ready = true;

	},

	_destroy: function() {
		this.element
			.removeClass("ui-sortable ui-sortable-disabled");
		this._mouseDestroy();

		for ( var i = this.items.length - 1; i >= 0; i-- ) {
			this.items[i].item.removeData(this.widgetName + "-item");
		}

		return this;
	},

	_setOption: function(key, value){
		if ( key === "disabled" ) {
			this.options[ key ] = value;

			this.widget().toggleClass( "ui-sortable-disabled", !!value );
		} else {
			// Don't call widget base _setOption for disable as it adds ui-state-disabled class
			$.Widget.prototype._setOption.apply(this, arguments);
		}
	},

	_mouseCapture: function(event, overrideHandle) {
		var currentItem = null,
			validHandle = false,
			that = this;

		if (this.reverting) {
			return false;
		}

		if(this.options.disabled || this.options.type === "static") {
			return false;
		}

		//We have to refresh the items data once first
		this._refreshItems(event);

		//Find out if the clicked node (or one of its parents) is a actual item in this.items
		$(event.target).parents().each(function() {
			if($.data(this, that.widgetName + "-item") === that) {
				currentItem = $(this);
				return false;
			}
		});
		if($.data(event.target, that.widgetName + "-item") === that) {
			currentItem = $(event.target);
		}

		if(!currentItem) {
			return false;
		}
		if(this.options.handle && !overrideHandle) {
			$(this.options.handle, currentItem).find("*").addBack().each(function() {
				if(this === event.target) {
					validHandle = true;
				}
			});
			if(!validHandle) {
				return false;
			}
		}

		this.currentItem = currentItem;
		this._removeCurrentsFromItems();
		return true;

	},

	_mouseStart: function(event, overrideHandle, noActivation) {

		var i, body,
			o = this.options;

		this.currentContainer = this;

		//We only need to call refreshPositions, because the refreshItems call has been moved to mouseCapture
		this.refreshPositions();

		//Create and append the visible helper
		this.helper = this._createHelper(event);

		//Cache the helper size
		this._cacheHelperProportions();

		/*
		 * - Position generation -
		 * This block generates everything position related - it's the core of draggables.
		 */

		//Cache the margins of the original element
		this._cacheMargins();

		//Get the next scrolling parent
		this.scrollParent = this.helper.scrollParent();

		//The element's absolute position on the page minus margins
		this.offset = this.currentItem.offset();
		this.offset = {
			top: this.offset.top - this.margins.top,
			left: this.offset.left - this.margins.left
		};

		$.extend(this.offset, {
			click: { //Where the click happened, relative to the element
				left: event.pageX - this.offset.left,
				top: event.pageY - this.offset.top
			},
			parent: this._getParentOffset(),
			relative: this._getRelativeOffset() //This is a relative to absolute position minus the actual position calculation - only used for relative positioned helper
		});

		// Only after we got the offset, we can change the helper's position to absolute
		// TODO: Still need to figure out a way to make relative sorting possible
		this.helper.css("position", "absolute");
		this.cssPosition = this.helper.css("position");

		//Generate the original position
		this.originalPosition = this._generatePosition(event);
		this.originalPageX = event.pageX;
		this.originalPageY = event.pageY;

		//Adjust the mouse offset relative to the helper if "cursorAt" is supplied
		(o.cursorAt && this._adjustOffsetFromHelper(o.cursorAt));

		//Cache the former DOM position
		this.domPosition = { prev: this.currentItem.prev()[0], parent: this.currentItem.parent()[0] };

		//If the helper is not the original, hide the original so it's not playing any role during the drag, won't cause anything bad this way
		if(this.helper[0] !== this.currentItem[0]) {
			this.currentItem.hide();
		}

		//Create the placeholder
		this._createPlaceholder();

		//Set a containment if given in the options
		if(o.containment) {
			this._setContainment();
		}

		if( o.cursor && o.cursor !== "auto" ) { // cursor option
			body = this.document.find( "body" );

			// support: IE
			this.storedCursor = body.css( "cursor" );
			body.css( "cursor", o.cursor );

			this.storedStylesheet = $( "<style>*{ cursor: "+o.cursor+" !important; }</style>" ).appendTo( body );
		}

		if(o.opacity) { // opacity option
			if (this.helper.css("opacity")) {
				this._storedOpacity = this.helper.css("opacity");
			}
			this.helper.css("opacity", o.opacity);
		}

		if(o.zIndex) { // zIndex option
			if (this.helper.css("zIndex")) {
				this._storedZIndex = this.helper.css("zIndex");
			}
			this.helper.css("zIndex", o.zIndex);
		}

		//Prepare scrolling
		if(this.scrollParent[0] !== document && this.scrollParent[0].tagName !== "HTML") {
			this.overflowOffset = this.scrollParent.offset();
		}

		//Call callbacks
		this._trigger("start", event, this._uiHash());

		//Recache the helper size
		if(!this._preserveHelperProportions) {
			this._cacheHelperProportions();
		}


		//Post "activate" events to possible containers
		if( !noActivation ) {
			for ( i = this.containers.length - 1; i >= 0; i-- ) {
				this.containers[ i ]._trigger( "activate", event, this._uiHash( this ) );
			}
		}

		//Prepare possible droppables
		if($.ui.ddmanager) {
			$.ui.ddmanager.current = this;
		}

		if ($.ui.ddmanager && !o.dropBehaviour) {
			$.ui.ddmanager.prepareOffsets(this, event);
		}

		this.dragging = true;

		this.helper.addClass("ui-sortable-helper");
		this._mouseDrag(event); //Execute the drag once - this causes the helper not to be visible before getting its correct position
		return true;

	},

	_mouseDrag: function(event) {
		var i, item, itemElement, intersection,
			o = this.options,
			scrolled = false;

		//Compute the helpers position
		this.position = this._generatePosition(event);
		this.positionAbs = this._convertPositionTo("absolute");

		if (!this.lastPositionAbs) {
			this.lastPositionAbs = this.positionAbs;
		}

		//Do scrolling
		if(this.options.scroll) {
			if(this.scrollParent[0] !== document && this.scrollParent[0].tagName !== "HTML") {

				if((this.overflowOffset.top + this.scrollParent[0].offsetHeight) - event.pageY < o.scrollSensitivity) {
					this.scrollParent[0].scrollTop = scrolled = this.scrollParent[0].scrollTop + o.scrollSpeed;
				} else if(event.pageY - this.overflowOffset.top < o.scrollSensitivity) {
					this.scrollParent[0].scrollTop = scrolled = this.scrollParent[0].scrollTop - o.scrollSpeed;
				}

				if((this.overflowOffset.left + this.scrollParent[0].offsetWidth) - event.pageX < o.scrollSensitivity) {
					this.scrollParent[0].scrollLeft = scrolled = this.scrollParent[0].scrollLeft + o.scrollSpeed;
				} else if(event.pageX - this.overflowOffset.left < o.scrollSensitivity) {
					this.scrollParent[0].scrollLeft = scrolled = this.scrollParent[0].scrollLeft - o.scrollSpeed;
				}

			} else {

				if(event.pageY - $(document).scrollTop() < o.scrollSensitivity) {
					scrolled = $(document).scrollTop($(document).scrollTop() - o.scrollSpeed);
				} else if($(window).height() - (event.pageY - $(document).scrollTop()) < o.scrollSensitivity) {
					scrolled = $(document).scrollTop($(document).scrollTop() + o.scrollSpeed);
				}

				if(event.pageX - $(document).scrollLeft() < o.scrollSensitivity) {
					scrolled = $(document).scrollLeft($(document).scrollLeft() - o.scrollSpeed);
				} else if($(window).width() - (event.pageX - $(document).scrollLeft()) < o.scrollSensitivity) {
					scrolled = $(document).scrollLeft($(document).scrollLeft() + o.scrollSpeed);
				}

			}

			if(scrolled !== false && $.ui.ddmanager && !o.dropBehaviour) {
				$.ui.ddmanager.prepareOffsets(this, event);
			}
		}

		//Regenerate the absolute position used for position checks
		this.positionAbs = this._convertPositionTo("absolute");

		//Set the helper position
		if(!this.options.axis || this.options.axis !== "y") {
			this.helper[0].style.left = this.position.left+"px";
		}
		if(!this.options.axis || this.options.axis !== "x") {
			this.helper[0].style.top = this.position.top+"px";
		}

		//Rearrange
		for (i = this.items.length - 1; i >= 0; i--) {

			//Cache variables and intersection, continue if no intersection
			item = this.items[i];
			itemElement = item.item[0];
			intersection = this._intersectsWithPointer(item);
			if (!intersection) {
				continue;
			}

			// Only put the placeholder inside the current Container, skip all
			// items form other containers. This works because when moving
			// an item from one container to another the
			// currentContainer is switched before the placeholder is moved.
			//
			// Without this moving items in "sub-sortables" can cause the placeholder to jitter
			// beetween the outer and inner container.
			if (item.instance !== this.currentContainer) {
				continue;
			}

			// cannot intersect with itself
			// no useless actions that have been done before
			// no action if the item moved is the parent of the item checked
			if (itemElement !== this.currentItem[0] &&
				this.placeholder[intersection === 1 ? "next" : "prev"]()[0] !== itemElement &&
				!$.contains(this.placeholder[0], itemElement) &&
				(this.options.type === "semi-dynamic" ? !$.contains(this.element[0], itemElement) : true)
			) {

				this.direction = intersection === 1 ? "down" : "up";

				if (this.options.tolerance === "pointer" || this._intersectsWithSides(item)) {
					this._rearrange(event, item);
				} else {
					break;
				}

				this._trigger("change", event, this._uiHash());
				break;
			}
		}

		//Post events to containers
		this._contactContainers(event);

		//Interconnect with droppables
		if($.ui.ddmanager) {
			$.ui.ddmanager.drag(this, event);
		}

		//Call callbacks
		this._trigger("sort", event, this._uiHash());

		this.lastPositionAbs = this.positionAbs;
		return false;

	},

	_mouseStop: function(event, noPropagation) {

		if(!event) {
			return;
		}

		//If we are using droppables, inform the manager about the drop
		if ($.ui.ddmanager && !this.options.dropBehaviour) {
			$.ui.ddmanager.drop(this, event);
		}

		if(this.options.revert) {
			var that = this,
				cur = this.placeholder.offset(),
				axis = this.options.axis,
				animation = {};

			if ( !axis || axis === "x" ) {
				animation.left = cur.left - this.offset.parent.left - this.margins.left + (this.offsetParent[0] === document.body ? 0 : this.offsetParent[0].scrollLeft);
			}
			if ( !axis || axis === "y" ) {
				animation.top = cur.top - this.offset.parent.top - this.margins.top + (this.offsetParent[0] === document.body ? 0 : this.offsetParent[0].scrollTop);
			}
			this.reverting = true;
			$(this.helper).animate( animation, parseInt(this.options.revert, 10) || 500, function() {
				that._clear(event);
			});
		} else {
			this._clear(event, noPropagation);
		}

		return false;

	},

	cancel: function() {

		if(this.dragging) {

			this._mouseUp({ target: null });

			if(this.options.helper === "original") {
				this.currentItem.css(this._storedCSS).removeClass("ui-sortable-helper");
			} else {
				this.currentItem.show();
			}

			//Post deactivating events to containers
			for (var i = this.containers.length - 1; i >= 0; i--){
				this.containers[i]._trigger("deactivate", null, this._uiHash(this));
				if(this.containers[i].containerCache.over) {
					this.containers[i]._trigger("out", null, this._uiHash(this));
					this.containers[i].containerCache.over = 0;
				}
			}

		}

		if (this.placeholder) {
			//$(this.placeholder[0]).remove(); would have been the jQuery way - unfortunately, it unbinds ALL events from the original node!
			if(this.placeholder[0].parentNode) {
				this.placeholder[0].parentNode.removeChild(this.placeholder[0]);
			}
			if(this.options.helper !== "original" && this.helper && this.helper[0].parentNode) {
				this.helper.remove();
			}

			$.extend(this, {
				helper: null,
				dragging: false,
				reverting: false,
				_noFinalSort: null
			});

			if(this.domPosition.prev) {
				$(this.domPosition.prev).after(this.currentItem);
			} else {
				$(this.domPosition.parent).prepend(this.currentItem);
			}
		}

		return this;

	},

	serialize: function(o) {

		var items = this._getItemsAsjQuery(o && o.connected),
			str = [];
		o = o || {};

		$(items).each(function() {
			var res = ($(o.item || this).attr(o.attribute || "id") || "").match(o.expression || (/(.+)[\-=_](.+)/));
			if (res) {
				str.push((o.key || res[1]+"[]")+"="+(o.key && o.expression ? res[1] : res[2]));
			}
		});

		if(!str.length && o.key) {
			str.push(o.key + "=");
		}

		return str.join("&");

	},

	toArray: function(o) {

		var items = this._getItemsAsjQuery(o && o.connected),
			ret = [];

		o = o || {};

		items.each(function() { ret.push($(o.item || this).attr(o.attribute || "id") || ""); });
		return ret;

	},

	/* Be careful with the following core functions */
	_intersectsWith: function(item) {

		var x1 = this.positionAbs.left,
			x2 = x1 + this.helperProportions.width,
			y1 = this.positionAbs.top,
			y2 = y1 + this.helperProportions.height,
			l = item.left,
			r = l + item.width,
			t = item.top,
			b = t + item.height,
			dyClick = this.offset.click.top,
			dxClick = this.offset.click.left,
			isOverElementHeight = ( this.options.axis === "x" ) || ( ( y1 + dyClick ) > t && ( y1 + dyClick ) < b ),
			isOverElementWidth = ( this.options.axis === "y" ) || ( ( x1 + dxClick ) > l && ( x1 + dxClick ) < r ),
			isOverElement = isOverElementHeight && isOverElementWidth;

		if ( this.options.tolerance === "pointer" ||
			this.options.forcePointerForContainers ||
			(this.options.tolerance !== "pointer" && this.helperProportions[this.floating ? "width" : "height"] > item[this.floating ? "width" : "height"])
		) {
			return isOverElement;
		} else {

			return (l < x1 + (this.helperProportions.width / 2) && // Right Half
				x2 - (this.helperProportions.width / 2) < r && // Left Half
				t < y1 + (this.helperProportions.height / 2) && // Bottom Half
				y2 - (this.helperProportions.height / 2) < b ); // Top Half

		}
	},

	_intersectsWithPointer: function(item) {

		var isOverElementHeight = (this.options.axis === "x") || isOverAxis(this.positionAbs.top + this.offset.click.top, item.top, item.height),
			isOverElementWidth = (this.options.axis === "y") || isOverAxis(this.positionAbs.left + this.offset.click.left, item.left, item.width),
			isOverElement = isOverElementHeight && isOverElementWidth,
			verticalDirection = this._getDragVerticalDirection(),
			horizontalDirection = this._getDragHorizontalDirection();

		if (!isOverElement) {
			return false;
		}

		return this.floating ?
			( ((horizontalDirection && horizontalDirection === "right") || verticalDirection === "down") ? 2 : 1 )
			: ( verticalDirection && (verticalDirection === "down" ? 2 : 1) );

	},

	_intersectsWithSides: function(item) {

		var isOverBottomHalf = isOverAxis(this.positionAbs.top + this.offset.click.top, item.top + (item.height/2), item.height),
			isOverRightHalf = isOverAxis(this.positionAbs.left + this.offset.click.left, item.left + (item.width/2), item.width),
			verticalDirection = this._getDragVerticalDirection(),
			horizontalDirection = this._getDragHorizontalDirection();

		if (this.floating && horizontalDirection) {
			return ((horizontalDirection === "right" && isOverRightHalf) || (horizontalDirection === "left" && !isOverRightHalf));
		} else {
			return verticalDirection && ((verticalDirection === "down" && isOverBottomHalf) || (verticalDirection === "up" && !isOverBottomHalf));
		}

	},

	_getDragVerticalDirection: function() {
		var delta = this.positionAbs.top - this.lastPositionAbs.top;
		return delta !== 0 && (delta > 0 ? "down" : "up");
	},

	_getDragHorizontalDirection: function() {
		var delta = this.positionAbs.left - this.lastPositionAbs.left;
		return delta !== 0 && (delta > 0 ? "right" : "left");
	},

	refresh: function(event) {
		this._refreshItems(event);
		this.refreshPositions();
		return this;
	},

	_connectWith: function() {
		var options = this.options;
		return options.connectWith.constructor === String ? [options.connectWith] : options.connectWith;
	},

	_getItemsAsjQuery: function(connected) {

		var i, j, cur, inst,
			items = [],
			queries = [],
			connectWith = this._connectWith();

		if(connectWith && connected) {
			for (i = connectWith.length - 1; i >= 0; i--){
				cur = $(connectWith[i]);
				for ( j = cur.length - 1; j >= 0; j--){
					inst = $.data(cur[j], this.widgetFullName);
					if(inst && inst !== this && !inst.options.disabled) {
						queries.push([$.isFunction(inst.options.items) ? inst.options.items.call(inst.element) : $(inst.options.items, inst.element).not(".ui-sortable-helper").not(".ui-sortable-placeholder"), inst]);
					}
				}
			}
		}

		queries.push([$.isFunction(this.options.items) ? this.options.items.call(this.element, null, { options: this.options, item: this.currentItem }) : $(this.options.items, this.element).not(".ui-sortable-helper").not(".ui-sortable-placeholder"), this]);

		for (i = queries.length - 1; i >= 0; i--){
			queries[i][0].each(function() {
				items.push(this);
			});
		}

		return $(items);

	},

	_removeCurrentsFromItems: function() {

		var list = this.currentItem.find(":data(" + this.widgetName + "-item)");

		this.items = $.grep(this.items, function (item) {
			for (var j=0; j < list.length; j++) {
				if(list[j] === item.item[0]) {
					return false;
				}
			}
			return true;
		});

	},

	_refreshItems: function(event) {

		this.items = [];
		this.containers = [this];

		var i, j, cur, inst, targetData, _queries, item, queriesLength,
			items = this.items,
			queries = [[$.isFunction(this.options.items) ? this.options.items.call(this.element[0], event, { item: this.currentItem }) : $(this.options.items, this.element), this]],
			connectWith = this._connectWith();

		if(connectWith && this.ready) { //Shouldn't be run the first time through due to massive slow-down
			for (i = connectWith.length - 1; i >= 0; i--){
				cur = $(connectWith[i]);
				for (j = cur.length - 1; j >= 0; j--){
					inst = $.data(cur[j], this.widgetFullName);
					if(inst && inst !== this && !inst.options.disabled) {
						queries.push([$.isFunction(inst.options.items) ? inst.options.items.call(inst.element[0], event, { item: this.currentItem }) : $(inst.options.items, inst.element), inst]);
						this.containers.push(inst);
					}
				}
			}
		}

		for (i = queries.length - 1; i >= 0; i--) {
			targetData = queries[i][1];
			_queries = queries[i][0];

			for (j=0, queriesLength = _queries.length; j < queriesLength; j++) {
				item = $(_queries[j]);

				item.data(this.widgetName + "-item", targetData); // Data for target checking (mouse manager)

				items.push({
					item: item,
					instance: targetData,
					width: 0, height: 0,
					left: 0, top: 0
				});
			}
		}

	},

	refreshPositions: function(fast) {

		//This has to be redone because due to the item being moved out/into the offsetParent, the offsetParent's position will change
		if(this.offsetParent && this.helper) {
			this.offset.parent = this._getParentOffset();
		}

		var i, item, t, p;

		for (i = this.items.length - 1; i >= 0; i--){
			item = this.items[i];

			//We ignore calculating positions of all connected containers when we're not over them
			if(item.instance !== this.currentContainer && this.currentContainer && item.item[0] !== this.currentItem[0]) {
				continue;
			}

			t = this.options.toleranceElement ? $(this.options.toleranceElement, item.item) : item.item;

			if (!fast) {
				item.width = t.outerWidth();
				item.height = t.outerHeight();
			}

			p = t.offset();
			item.left = p.left;
			item.top = p.top;
		}

		if(this.options.custom && this.options.custom.refreshContainers) {
			this.options.custom.refreshContainers.call(this);
		} else {
			for (i = this.containers.length - 1; i >= 0; i--){
				p = this.containers[i].element.offset();
				this.containers[i].containerCache.left = p.left;
				this.containers[i].containerCache.top = p.top;
				this.containers[i].containerCache.width	= this.containers[i].element.outerWidth();
				this.containers[i].containerCache.height = this.containers[i].element.outerHeight();
			}
		}

		return this;
	},

	_createPlaceholder: function(that) {
		that = that || this;
		var className,
			o = that.options;

		if(!o.placeholder || o.placeholder.constructor === String) {
			className = o.placeholder;
			o.placeholder = {
				element: function() {

					var nodeName = that.currentItem[0].nodeName.toLowerCase(),
						element = $( "<" + nodeName + ">", that.document[0] )
							.addClass(className || that.currentItem[0].className+" ui-sortable-placeholder")
							.removeClass("ui-sortable-helper");

					if ( nodeName === "tr" ) {
						that.currentItem.children().each(function() {
							$( "<td>&#160;</td>", that.document[0] )
								.attr( "colspan", $( this ).attr( "colspan" ) || 1 )
								.appendTo( element );
						});
					} else if ( nodeName === "img" ) {
						element.attr( "src", that.currentItem.attr( "src" ) );
					}

					if ( !className ) {
						element.css( "visibility", "hidden" );
					}

					return element;
				},
				update: function(container, p) {

					// 1. If a className is set as 'placeholder option, we don't force sizes - the class is responsible for that
					// 2. The option 'forcePlaceholderSize can be enabled to force it even if a class name is specified
					if(className && !o.forcePlaceholderSize) {
						return;
					}

					//If the element doesn't have a actual height by itself (without styles coming from a stylesheet), it receives the inline height from the dragged item
					if(!p.height()) { p.height(that.currentItem.innerHeight() - parseInt(that.currentItem.css("paddingTop")||0, 10) - parseInt(that.currentItem.css("paddingBottom")||0, 10)); }
					if(!p.width()) { p.width(that.currentItem.innerWidth() - parseInt(that.currentItem.css("paddingLeft")||0, 10) - parseInt(that.currentItem.css("paddingRight")||0, 10)); }
				}
			};
		}

		//Create the placeholder
		that.placeholder = $(o.placeholder.element.call(that.element, that.currentItem));

		//Append it after the actual current item
		that.currentItem.after(that.placeholder);

		//Update the size of the placeholder (TODO: Logic to fuzzy, see line 316/317)
		o.placeholder.update(that, that.placeholder);

	},

	_contactContainers: function(event) {
		var i, j, dist, itemWithLeastDistance, posProperty, sizeProperty, base, cur, nearBottom, floating,
			innermostContainer = null,
			innermostIndex = null;

		// get innermost container that intersects with item
		for (i = this.containers.length - 1; i >= 0; i--) {

			// never consider a container that's located within the item itself
			if($.contains(this.currentItem[0], this.containers[i].element[0])) {
				continue;
			}

			if(this._intersectsWith(this.containers[i].containerCache)) {

				// if we've already found a container and it's more "inner" than this, then continue
				if(innermostContainer && $.contains(this.containers[i].element[0], innermostContainer.element[0])) {
					continue;
				}

				innermostContainer = this.containers[i];
				innermostIndex = i;

			} else {
				// container doesn't intersect. trigger "out" event if necessary
				if(this.containers[i].containerCache.over) {
					this.containers[i]._trigger("out", event, this._uiHash(this));
					this.containers[i].containerCache.over = 0;
				}
			}

		}

		// if no intersecting containers found, return
		if(!innermostContainer) {
			return;
		}

		// move the item into the container if it's not there already
		if(this.containers.length === 1) {
			if (!this.containers[innermostIndex].containerCache.over) {
				this.containers[innermostIndex]._trigger("over", event, this._uiHash(this));
				this.containers[innermostIndex].containerCache.over = 1;
			}
		} else {

			//When entering a new container, we will find the item with the least distance and append our item near it
			dist = 10000;
			itemWithLeastDistance = null;
			floating = innermostContainer.floating || isFloating(this.currentItem);
			posProperty = floating ? "left" : "top";
			sizeProperty = floating ? "width" : "height";
			base = this.positionAbs[posProperty] + this.offset.click[posProperty];
			for (j = this.items.length - 1; j >= 0; j--) {
				if(!$.contains(this.containers[innermostIndex].element[0], this.items[j].item[0])) {
					continue;
				}
				if(this.items[j].item[0] === this.currentItem[0]) {
					continue;
				}
				if (floating && !isOverAxis(this.positionAbs.top + this.offset.click.top, this.items[j].top, this.items[j].height)) {
					continue;
				}
				cur = this.items[j].item.offset()[posProperty];
				nearBottom = false;
				if(Math.abs(cur - base) > Math.abs(cur + this.items[j][sizeProperty] - base)){
					nearBottom = true;
					cur += this.items[j][sizeProperty];
				}

				if(Math.abs(cur - base) < dist) {
					dist = Math.abs(cur - base); itemWithLeastDistance = this.items[j];
					this.direction = nearBottom ? "up": "down";
				}
			}

			//Check if dropOnEmpty is enabled
			if(!itemWithLeastDistance && !this.options.dropOnEmpty) {
				return;
			}

			if(this.currentContainer === this.containers[innermostIndex]) {
				return;
			}

			itemWithLeastDistance ? this._rearrange(event, itemWithLeastDistance, null, true) : this._rearrange(event, null, this.containers[innermostIndex].element, true);
			this._trigger("change", event, this._uiHash());
			this.containers[innermostIndex]._trigger("change", event, this._uiHash(this));
			this.currentContainer = this.containers[innermostIndex];

			//Update the placeholder
			this.options.placeholder.update(this.currentContainer, this.placeholder);

			this.containers[innermostIndex]._trigger("over", event, this._uiHash(this));
			this.containers[innermostIndex].containerCache.over = 1;
		}


	},

	_createHelper: function(event) {

		var o = this.options,
			helper = $.isFunction(o.helper) ? $(o.helper.apply(this.element[0], [event, this.currentItem])) : (o.helper === "clone" ? this.currentItem.clone() : this.currentItem);

		//Add the helper to the DOM if that didn't happen already
		if(!helper.parents("body").length) {
			$(o.appendTo !== "parent" ? o.appendTo : this.currentItem[0].parentNode)[0].appendChild(helper[0]);
		}

		if(helper[0] === this.currentItem[0]) {
			this._storedCSS = { width: this.currentItem[0].style.width, height: this.currentItem[0].style.height, position: this.currentItem.css("position"), top: this.currentItem.css("top"), left: this.currentItem.css("left") };
		}

		if(!helper[0].style.width || o.forceHelperSize) {
			helper.width(this.currentItem.width());
		}
		if(!helper[0].style.height || o.forceHelperSize) {
			helper.height(this.currentItem.height());
		}

		return helper;

	},

	_adjustOffsetFromHelper: function(obj) {
		if (typeof obj === "string") {
			obj = obj.split(" ");
		}
		if ($.isArray(obj)) {
			obj = {left: +obj[0], top: +obj[1] || 0};
		}
		if ("left" in obj) {
			this.offset.click.left = obj.left + this.margins.left;
		}
		if ("right" in obj) {
			this.offset.click.left = this.helperProportions.width - obj.right + this.margins.left;
		}
		if ("top" in obj) {
			this.offset.click.top = obj.top + this.margins.top;
		}
		if ("bottom" in obj) {
			this.offset.click.top = this.helperProportions.height - obj.bottom + this.margins.top;
		}
	},

	_getParentOffset: function() {


		//Get the offsetParent and cache its position
		this.offsetParent = this.helper.offsetParent();
		var po = this.offsetParent.offset();

		// This is a special case where we need to modify a offset calculated on start, since the following happened:
		// 1. The position of the helper is absolute, so it's position is calculated based on the next positioned parent
		// 2. The actual offset parent is a child of the scroll parent, and the scroll parent isn't the document, which means that
		//    the scroll is included in the initial calculation of the offset of the parent, and never recalculated upon drag
		if(this.cssPosition === "absolute" && this.scrollParent[0] !== document && $.contains(this.scrollParent[0], this.offsetParent[0])) {
			po.left += this.scrollParent.scrollLeft();
			po.top += this.scrollParent.scrollTop();
		}

		// This needs to be actually done for all browsers, since pageX/pageY includes this information
		// with an ugly IE fix
		if( this.offsetParent[0] === document.body || (this.offsetParent[0].tagName && this.offsetParent[0].tagName.toLowerCase() === "html" && $.ui.ie)) {
			po = { top: 0, left: 0 };
		}

		return {
			top: po.top + (parseInt(this.offsetParent.css("borderTopWidth"),10) || 0),
			left: po.left + (parseInt(this.offsetParent.css("borderLeftWidth"),10) || 0)
		};

	},

	_getRelativeOffset: function() {

		if(this.cssPosition === "relative") {
			var p = this.currentItem.position();
			return {
				top: p.top - (parseInt(this.helper.css("top"),10) || 0) + this.scrollParent.scrollTop(),
				left: p.left - (parseInt(this.helper.css("left"),10) || 0) + this.scrollParent.scrollLeft()
			};
		} else {
			return { top: 0, left: 0 };
		}

	},

	_cacheMargins: function() {
		this.margins = {
			left: (parseInt(this.currentItem.css("marginLeft"),10) || 0),
			top: (parseInt(this.currentItem.css("marginTop"),10) || 0)
		};
	},

	_cacheHelperProportions: function() {
		this.helperProportions = {
			width: this.helper.outerWidth(),
			height: this.helper.outerHeight()
		};
	},

	_setContainment: function() {

		var ce, co, over,
			o = this.options;
		if(o.containment === "parent") {
			o.containment = this.helper[0].parentNode;
		}
		if(o.containment === "document" || o.containment === "window") {
			this.containment = [
				0 - this.offset.relative.left - this.offset.parent.left,
				0 - this.offset.relative.top - this.offset.parent.top,
				$(o.containment === "document" ? document : window).width() - this.helperProportions.width - this.margins.left,
				($(o.containment === "document" ? document : window).height() || document.body.parentNode.scrollHeight) - this.helperProportions.height - this.margins.top
			];
		}

		if(!(/^(document|window|parent)$/).test(o.containment)) {
			ce = $(o.containment)[0];
			co = $(o.containment).offset();
			over = ($(ce).css("overflow") !== "hidden");

			this.containment = [
				co.left + (parseInt($(ce).css("borderLeftWidth"),10) || 0) + (parseInt($(ce).css("paddingLeft"),10) || 0) - this.margins.left,
				co.top + (parseInt($(ce).css("borderTopWidth"),10) || 0) + (parseInt($(ce).css("paddingTop"),10) || 0) - this.margins.top,
				co.left+(over ? Math.max(ce.scrollWidth,ce.offsetWidth) : ce.offsetWidth) - (parseInt($(ce).css("borderLeftWidth"),10) || 0) - (parseInt($(ce).css("paddingRight"),10) || 0) - this.helperProportions.width - this.margins.left,
				co.top+(over ? Math.max(ce.scrollHeight,ce.offsetHeight) : ce.offsetHeight) - (parseInt($(ce).css("borderTopWidth"),10) || 0) - (parseInt($(ce).css("paddingBottom"),10) || 0) - this.helperProportions.height - this.margins.top
			];
		}

	},

	_convertPositionTo: function(d, pos) {

		if(!pos) {
			pos = this.position;
		}
		var mod = d === "absolute" ? 1 : -1,
			scroll = this.cssPosition === "absolute" && !(this.scrollParent[0] !== document && $.contains(this.scrollParent[0], this.offsetParent[0])) ? this.offsetParent : this.scrollParent,
			scrollIsRootNode = (/(html|body)/i).test(scroll[0].tagName);

		return {
			top: (
				pos.top	+																// The absolute mouse position
				this.offset.relative.top * mod +										// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.parent.top * mod -											// The offsetParent's offset without borders (offset + border)
				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : scroll.scrollTop() ) ) * mod)
			),
			left: (
				pos.left +																// The absolute mouse position
				this.offset.relative.left * mod +										// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.parent.left * mod	-										// The offsetParent's offset without borders (offset + border)
				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollLeft() : scrollIsRootNode ? 0 : scroll.scrollLeft() ) * mod)
			)
		};

	},

	_generatePosition: function(event) {

		var top, left,
			o = this.options,
			pageX = event.pageX,
			pageY = event.pageY,
			scroll = this.cssPosition === "absolute" && !(this.scrollParent[0] !== document && $.contains(this.scrollParent[0], this.offsetParent[0])) ? this.offsetParent : this.scrollParent, scrollIsRootNode = (/(html|body)/i).test(scroll[0].tagName);

		// This is another very weird special case that only happens for relative elements:
		// 1. If the css position is relative
		// 2. and the scroll parent is the document or similar to the offset parent
		// we have to refresh the relative offset during the scroll so there are no jumps
		if(this.cssPosition === "relative" && !(this.scrollParent[0] !== document && this.scrollParent[0] !== this.offsetParent[0])) {
			this.offset.relative = this._getRelativeOffset();
		}

		/*
		 * - Position constraining -
		 * Constrain the position to a mix of grid, containment.
		 */

		if(this.originalPosition) { //If we are not dragging yet, we won't check for options

			if(this.containment) {
				if(event.pageX - this.offset.click.left < this.containment[0]) {
					pageX = this.containment[0] + this.offset.click.left;
				}
				if(event.pageY - this.offset.click.top < this.containment[1]) {
					pageY = this.containment[1] + this.offset.click.top;
				}
				if(event.pageX - this.offset.click.left > this.containment[2]) {
					pageX = this.containment[2] + this.offset.click.left;
				}
				if(event.pageY - this.offset.click.top > this.containment[3]) {
					pageY = this.containment[3] + this.offset.click.top;
				}
			}

			if(o.grid) {
				top = this.originalPageY + Math.round((pageY - this.originalPageY) / o.grid[1]) * o.grid[1];
				pageY = this.containment ? ( (top - this.offset.click.top >= this.containment[1] && top - this.offset.click.top <= this.containment[3]) ? top : ((top - this.offset.click.top >= this.containment[1]) ? top - o.grid[1] : top + o.grid[1])) : top;

				left = this.originalPageX + Math.round((pageX - this.originalPageX) / o.grid[0]) * o.grid[0];
				pageX = this.containment ? ( (left - this.offset.click.left >= this.containment[0] && left - this.offset.click.left <= this.containment[2]) ? left : ((left - this.offset.click.left >= this.containment[0]) ? left - o.grid[0] : left + o.grid[0])) : left;
			}

		}

		return {
			top: (
				pageY -																// The absolute mouse position
				this.offset.click.top -													// Click offset (relative to the element)
				this.offset.relative.top	-											// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.parent.top +												// The offsetParent's offset without borders (offset + border)
				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollTop() : ( scrollIsRootNode ? 0 : scroll.scrollTop() ) ))
			),
			left: (
				pageX -																// The absolute mouse position
				this.offset.click.left -												// Click offset (relative to the element)
				this.offset.relative.left	-											// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.parent.left +												// The offsetParent's offset without borders (offset + border)
				( ( this.cssPosition === "fixed" ? -this.scrollParent.scrollLeft() : scrollIsRootNode ? 0 : scroll.scrollLeft() ))
			)
		};

	},

	_rearrange: function(event, i, a, hardRefresh) {

		a ? a[0].appendChild(this.placeholder[0]) : i.item[0].parentNode.insertBefore(this.placeholder[0], (this.direction === "down" ? i.item[0] : i.item[0].nextSibling));

		//Various things done here to improve the performance:
		// 1. we create a setTimeout, that calls refreshPositions
		// 2. on the instance, we have a counter variable, that get's higher after every append
		// 3. on the local scope, we copy the counter variable, and check in the timeout, if it's still the same
		// 4. this lets only the last addition to the timeout stack through
		this.counter = this.counter ? ++this.counter : 1;
		var counter = this.counter;

		this._delay(function() {
			if(counter === this.counter) {
				this.refreshPositions(!hardRefresh); //Precompute after each DOM insertion, NOT on mousemove
			}
		});

	},

	_clear: function(event, noPropagation) {

		this.reverting = false;
		// We delay all events that have to be triggered to after the point where the placeholder has been removed and
		// everything else normalized again
		var i,
			delayedTriggers = [];

		// We first have to update the dom position of the actual currentItem
		// Note: don't do it if the current item is already removed (by a user), or it gets reappended (see #4088)
		if(!this._noFinalSort && this.currentItem.parent().length) {
			this.placeholder.before(this.currentItem);
		}
		this._noFinalSort = null;

		if(this.helper[0] === this.currentItem[0]) {
			for(i in this._storedCSS) {
				if(this._storedCSS[i] === "auto" || this._storedCSS[i] === "static") {
					this._storedCSS[i] = "";
				}
			}
			this.currentItem.css(this._storedCSS).removeClass("ui-sortable-helper");
		} else {
			this.currentItem.show();
		}

		if(this.fromOutside && !noPropagation) {
			delayedTriggers.push(function(event) { this._trigger("receive", event, this._uiHash(this.fromOutside)); });
		}
		if((this.fromOutside || this.domPosition.prev !== this.currentItem.prev().not(".ui-sortable-helper")[0] || this.domPosition.parent !== this.currentItem.parent()[0]) && !noPropagation) {
			delayedTriggers.push(function(event) { this._trigger("update", event, this._uiHash()); }); //Trigger update callback if the DOM position has changed
		}

		// Check if the items Container has Changed and trigger appropriate
		// events.
		if (this !== this.currentContainer) {
			if(!noPropagation) {
				delayedTriggers.push(function(event) { this._trigger("remove", event, this._uiHash()); });
				delayedTriggers.push((function(c) { return function(event) { c._trigger("receive", event, this._uiHash(this)); };  }).call(this, this.currentContainer));
				delayedTriggers.push((function(c) { return function(event) { c._trigger("update", event, this._uiHash(this));  }; }).call(this, this.currentContainer));
			}
		}


		//Post events to containers
		for (i = this.containers.length - 1; i >= 0; i--){
			if(!noPropagation) {
				delayedTriggers.push((function(c) { return function(event) { c._trigger("deactivate", event, this._uiHash(this)); };  }).call(this, this.containers[i]));
			}
			if(this.containers[i].containerCache.over) {
				delayedTriggers.push((function(c) { return function(event) { c._trigger("out", event, this._uiHash(this)); };  }).call(this, this.containers[i]));
				this.containers[i].containerCache.over = 0;
			}
		}

		//Do what was originally in plugins
		if ( this.storedCursor ) {
			this.document.find( "body" ).css( "cursor", this.storedCursor );
			this.storedStylesheet.remove();
		}
		if(this._storedOpacity) {
			this.helper.css("opacity", this._storedOpacity);
		}
		if(this._storedZIndex) {
			this.helper.css("zIndex", this._storedZIndex === "auto" ? "" : this._storedZIndex);
		}

		this.dragging = false;
		if(this.cancelHelperRemoval) {
			if(!noPropagation) {
				this._trigger("beforeStop", event, this._uiHash());
				for (i=0; i < delayedTriggers.length; i++) {
					delayedTriggers[i].call(this, event);
				} //Trigger all delayed events
				this._trigger("stop", event, this._uiHash());
			}

			this.fromOutside = false;
			return false;
		}

		if(!noPropagation) {
			this._trigger("beforeStop", event, this._uiHash());
		}

		//$(this.placeholder[0]).remove(); would have been the jQuery way - unfortunately, it unbinds ALL events from the original node!
		this.placeholder[0].parentNode.removeChild(this.placeholder[0]);

		if(this.helper[0] !== this.currentItem[0]) {
			this.helper.remove();
		}
		this.helper = null;

		if(!noPropagation) {
			for (i=0; i < delayedTriggers.length; i++) {
				delayedTriggers[i].call(this, event);
			} //Trigger all delayed events
			this._trigger("stop", event, this._uiHash());
		}

		this.fromOutside = false;
		return true;

	},

	_trigger: function() {
		if ($.Widget.prototype._trigger.apply(this, arguments) === false) {
			this.cancel();
		}
	},

	_uiHash: function(_inst) {
		var inst = _inst || this;
		return {
			helper: inst.helper,
			placeholder: inst.placeholder || $([]),
			position: inst.position,
			originalPosition: inst.originalPosition,
			offset: inst.positionAbs,
			item: inst.currentItem,
			sender: _inst ? _inst.element : null
		};
	}

});

})(jQuery);