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Editing: sortable.js

/*!
 * jQuery UI Sortable 1.13.3
 * https://jqueryui.com
 *
 * Copyright OpenJS Foundation and other contributors
 * Released under the MIT license.
 * https://jquery.org/license
 */

//>>label: Sortable
//>>group: Interactions
//>>description: Enables items in a list to be sorted using the mouse.
//>>docs: https://api.jqueryui.com/sortable/
//>>demos: https://jqueryui.com/sortable/
//>>css.structure: ../../themes/base/sortable.css

( function( factory ) {
	"use strict";

if ( typeof define === "function" && define.amd ) {

// AMD. Register as an anonymous module.
		define( [
			"jquery",
			"./mouse",
			"../data",
			"../ie",
			"../scroll-parent",
			"../version",
			"../widget"
		], factory );
	} else {

// Browser globals
		factory( jQuery );
	}
} )( function( $ ) {
"use strict";

return $.widget( "ui.sortable", $.ui.mouse, {
	version: "1.13.3",
	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
	},

_isOverAxis: function( x, reference, size ) {
		return ( x >= reference ) && ( x < ( reference + size ) );
	},

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

_create: function() {
		this.containerCache = {};
		this._addClass( "ui-sortable" );

//Get the items
		this.refresh();

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

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

this._setHandleClassName();

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

_setOption: function( key, value ) {
		this._super( key, value );

if ( key === "handle" ) {
			this._setHandleClassName();
		}
	},

_setHandleClassName: function() {
		var that = this;
		this._removeClass( this.element.find( ".ui-sortable-handle" ), "ui-sortable-handle" );
		$.each( this.items, function() {
			that._addClass(
				this.instance.options.handle ?
					this.item.find( this.instance.options.handle ) :
					this.item,
				"ui-sortable-handle"
			);
		} );
	},

_destroy: function() {
		this._mouseDestroy();

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

return this;
	},

_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();

//Prepare the dragged items parent
		this.appendTo = $( o.appendTo !== "parent" ?
				o.appendTo :
				this.currentItem.parent() );

//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();

//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
			},

// This is a relative to absolute position minus the actual position calculation -
			// only used for relative positioned helper
			relative: this._getRelativeOffset()
		} );

// After we get the helper offset, but before we get the parent 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" );

//Adjust the mouse offset relative to the helper if "cursorAt" is supplied
		if ( 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();

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

$.extend( this.offset, {
			parent: this._getParentOffset()
		} );

//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 );
		}

// We need to make sure to grab the zIndex before setting the
		// opacity, because setting the opacity to anything lower than 1
		// causes the zIndex to change from "auto" to 0.
		if ( o.zIndex ) { // zIndex option
			if ( this.helper.css( "zIndex" ) ) {
				this._storedZIndex = this.helper.css( "zIndex" );
			}
			this.helper.css( "zIndex", o.zIndex );
		}

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

//Prepare scrolling
		if ( this.scrollParent[ 0 ] !== this.document[ 0 ] &&
				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._addClass( this.helper, "ui-sortable-helper" );

//Move the helper, if needed
		if ( !this.helper.parent().is( this.appendTo ) ) {
			this.helper.detach().appendTo( this.appendTo );

//Update position
			this.offset.parent = this._getParentOffset();
		}

//Generate the original position
		this.position = this.originalPosition = this._generatePosition( event );
		this.originalPageX = event.pageX;
		this.originalPageY = event.pageY;
		this.lastPositionAbs = this.positionAbs = this._convertPositionTo( "absolute" );

this._mouseDrag( event );

return true;

_scroll: function( event ) {
		var o = this.options,
			scrolled = false;

if ( this.scrollParent[ 0 ] !== this.document[ 0 ] &&
				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 - this.document.scrollTop() < o.scrollSensitivity ) {
				scrolled = this.document.scrollTop( this.document.scrollTop() - o.scrollSpeed );
			} else if ( this.window.height() - ( event.pageY - this.document.scrollTop() ) <
					o.scrollSensitivity ) {
				scrolled = this.document.scrollTop( this.document.scrollTop() + o.scrollSpeed );
			}

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

}

return scrolled;
	},

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

//Compute the helpers position
		this.position = this._generatePosition( event );
		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";
		}

//Do scrolling
		if ( o.scroll ) {
			if ( this._scroll( event ) !== false ) {

//Update item positions used in position checks
				this._refreshItemPositions( true );

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

this.dragDirection = {
			vertical: this._getDragVerticalDirection(),
			horizontal: this._getDragHorizontalDirection()
		};

//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 from 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 between 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 ] === this.document[ 0 ].body ?
						0 :
						this.offsetParent[ 0 ].scrollLeft
					);
			}
			if ( !axis || axis === "y" ) {
				animation.top = cur.top - this.offset.parent.top - this.margins.top +
					( this.offsetParent[ 0 ] === this.document[ 0 ].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( new $.Event( "mouseup", { target: null } ) );

if ( this.options.helper === "original" ) {
				this.currentItem.css( this._storedCSS );
				this._removeClass( this.currentItem, "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 verticalDirection, horizontalDirection,
			isOverElementHeight = ( this.options.axis === "x" ) ||
				this._isOverAxis(
					this.positionAbs.top + this.offset.click.top, item.top, item.height ),
			isOverElementWidth = ( this.options.axis === "y" ) ||
				this._isOverAxis(
					this.positionAbs.left + this.offset.click.left, item.left, item.width ),
			isOverElement = isOverElementHeight && isOverElementWidth;

if ( !isOverElement ) {
			return false;
		}

verticalDirection = this.dragDirection.vertical;
		horizontalDirection = this.dragDirection.horizontal;

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

_intersectsWithSides: function( item ) {

var isOverBottomHalf = this._isOverAxis( this.positionAbs.top +
				this.offset.click.top, item.top + ( item.height / 2 ), item.height ),
			isOverRightHalf = this._isOverAxis( this.positionAbs.left +
				this.offset.click.left, item.left + ( item.width / 2 ), item.width ),
			verticalDirection = this.dragDirection.vertical,
			horizontalDirection = this.dragDirection.horizontal;

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

queries.push( [ typeof this.options.items === "function" ?
			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 ] );

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

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 = [ [ typeof this.options.items === "function" ?
				this.options.items.call( this.element[ 0 ], event, { item: this.currentItem } ) :
				$( this.options.items, this.element ), this ] ],
			connectWith = this._connectWith();

//Shouldn't be run the first time through due to massive slow-down
		if ( connectWith && this.ready ) {
			for ( i = connectWith.length - 1; i >= 0; i-- ) {
				cur = $( connectWith[ i ], this.document[ 0 ] );
				for ( j = cur.length - 1; j >= 0; j-- ) {
					inst = $.data( cur[ j ], this.widgetFullName );
					if ( inst && inst !== this && !inst.options.disabled ) {
						queries.push( [ typeof inst.options.items === "function" ?
							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 ] );

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

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

_refreshItemPositions: function( fast ) {
		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 ( this.currentContainer && item.instance !== 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;
		}
	},

refreshPositions: function( fast ) {

// Determine whether items are being displayed horizontally
		this.floating = this.items.length ?
			this.options.axis === "x" || this._isFloating( this.items[ 0 ].item ) :
			false;

// 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();
		}

this._refreshItemPositions( fast );

var i, p;

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, nodeName,
			o = that.options;

if ( !o.placeholder || o.placeholder.constructor === String ) {
			className = o.placeholder;
			nodeName = that.currentItem[ 0 ].nodeName.toLowerCase();
			o.placeholder = {
				element: function() {

var element = $( "<" + nodeName + ">", that.document[ 0 ] );

that._addClass( element, "ui-sortable-placeholder",
							className || that.currentItem[ 0 ].className )
						._removeClass( element, "ui-sortable-helper" );

if ( nodeName === "tbody" ) {
						that._createTrPlaceholder(
							that.currentItem.find( "tr" ).eq( 0 ),
							$( "<tr>", that.document[ 0 ] ).appendTo( element )
						);
					} else if ( nodeName === "tr" ) {
						that._createTrPlaceholder( that.currentItem, 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 or width by itself (without
					// styles coming from a stylesheet), it receives the inline height and width
					// from the dragged item. Or, if it's a tbody or tr, it's going to have a height
					// anyway since we're populating them with <td>s above, but they're unlikely to
					// be the correct height on their own if the row heights are dynamic, so we'll
					// always assign the height of the dragged item given forcePlaceholderSize
					// is true.
					if ( !p.height() || ( o.forcePlaceholderSize &&
							( nodeName === "tbody" || nodeName === "tr" ) ) ) {
						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 );

_createTrPlaceholder: function( sourceTr, targetTr ) {
		var that = this;

sourceTr.children().each( function() {
			$( "<td>&#160;</td>", that.document[ 0 ] )
				.attr( "colspan", $( this ).attr( "colspan" ) || 1 )
				.appendTo( targetTr );
		} );
	},

_contactContainers: function( event ) {
		var i, j, dist, itemWithLeastDistance, posProperty, sizeProperty, cur, nearBottom,
			floating, axis,
			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 || this._isFloating( this.currentItem );
			posProperty = floating ? "left" : "top";
			sizeProperty = floating ? "width" : "height";
			axis = floating ? "pageX" : "pageY";

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;
				}

cur = this.items[ j ].item.offset()[ posProperty ];
				nearBottom = false;
				if ( event[ axis ] - cur > this.items[ j ][ sizeProperty ] / 2 ) {
					nearBottom = true;
				}

if ( Math.abs( event[ axis ] - cur ) < dist ) {
					dist = Math.abs( event[ axis ] - cur );
					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 ] ) {
				if ( !this.currentContainer.containerCache.over ) {
					this.containers[ innermostIndex ]._trigger( "over", event, this._uiHash() );
					this.currentContainer.containerCache.over = 1;
				}
				return;
			}

if ( itemWithLeastDistance ) {
				this._rearrange( event, itemWithLeastDistance, null, true );
			} else {
				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 );

//Update scrollParent
			this.scrollParent = this.placeholder.scrollParent();

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

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

_createHelper: function( event ) {

var o = this.options,
			helper = typeof o.helper === "function" ?
				$( 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 ) {
			this.appendTo[ 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 ( Array.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 ] !== this.document[ 0 ] &&
				$.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 ] === this.document[ 0 ].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" ?
					this.document.width() :
					this.window.width() - this.helperProportions.width - this.margins.left,
				( o.containment === "document" ?
					( this.document.height() || document.body.parentNode.scrollHeight ) :
					this.window.height() || this.document[ 0 ].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 ] !== this.document[ 0 ] &&
				$.contains( this.scrollParent[ 0 ], this.offsetParent[ 0 ] ) ) ?
					this.offsetParent :
					this.scrollParent,
			scrollIsRootNode = ( /(html|body)/i ).test( scroll[ 0 ].tagName );

return {
			top: (

// The absolute mouse position
				pos.top	+

// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.relative.top * mod +

// The offsetParent's offset without borders (offset + border)
				this.offset.parent.top * mod -
				( ( this.cssPosition === "fixed" ?
					-this.scrollParent.scrollTop() :
					( scrollIsRootNode ? 0 : scroll.scrollTop() ) ) * mod )
			),
			left: (

// The absolute mouse position
				pos.left +

// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.relative.left * mod +

// The offsetParent's offset without borders (offset + border)
				this.offset.parent.left * mod	-
				( ( 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 ] !== this.document[ 0 ] &&
				$.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 ] !== this.document[ 0 ] &&
				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: (

// The absolute mouse position
				pageY -

// Click offset (relative to the element)
				this.offset.click.top -

// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.relative.top -

// The offsetParent's offset without borders (offset + border)
				this.offset.parent.top +
				( ( this.cssPosition === "fixed" ?
					-this.scrollParent.scrollTop() :
					( scrollIsRootNode ? 0 : scroll.scrollTop() ) ) )
			),
			left: (

// The absolute mouse position
				pageX -

// Click offset (relative to the element)
				this.offset.click.left -

// Only for relative positioned nodes: Relative offset from element to offset parent
				this.offset.relative.left -

// The offsetParent's offset without borders (offset + border)
				this.offset.parent.left +
				( ( this.cssPosition === "fixed" ?
					-this.scrollParent.scrollLeft() :
					scrollIsRootNode ? 0 : scroll.scrollLeft() ) )
			)
		};

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

if ( a ) {
			a[ 0 ].appendChild( this.placeholder[ 0 ] );
		} else {
			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 ) {

//Precompute after each DOM insertion, NOT on mousemove
				this.refreshPositions( !hardRefresh );
			}
		} );

_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 );
			this._removeClass( this.currentItem, "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 ) {

// Trigger update callback if the DOM position has changed
			delayedTriggers.push( function( event ) {
				this._trigger( "update", event, this._uiHash() );
			} );
		}

// 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
		function delayEvent( type, instance, container ) {
			return function( event ) {
				container._trigger( type, event, instance._uiHash( instance ) );
			};
		}
		for ( i = this.containers.length - 1; i >= 0; i-- ) {
			if ( !noPropagation ) {
				delayedTriggers.push( delayEvent( "deactivate", this, this.containers[ i ] ) );
			}
			if ( this.containers[ i ].containerCache.over ) {
				delayedTriggers.push( delayEvent( "out", 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 ( !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.cancelHelperRemoval ) {
			if ( this.helper[ 0 ] !== this.currentItem[ 0 ] ) {
				this.helper.remove();
			}
			this.helper = null;
		}

if ( !noPropagation ) {
			for ( i = 0; i < delayedTriggers.length; i++ ) {

// Trigger all delayed events
				delayedTriggers[ i ].call( this, event );
			}
			this._trigger( "stop", event, this._uiHash() );
		}

this.fromOutside = false;
		return !this.cancelHelperRemoval;

_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
		};
	}

} );

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