/*
 * Modified By Tobias Hößl (scrolling problem)
 *
 *
 * jQuery UI Nested Sortable
 * v 2.0 / 29 oct 2012
 * http://mjsarfatti.com/sandbox/nestedSortable
 *
 * Depends on:
 *	 jquery.ui.sortable.js 1.10+
 *
 * Copyright (c) 2010-2013 Manuele J Sarfatti
 * Licensed under the MIT License
 * http://www.opensource.org/licenses/mit-license.php
 */
(function( factory ) {
    "use strict";

    var define = window.define;

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

        // AMD. Register as an anonymous module.
        define([
            "jquery",
            "jquery-ui/sortable"
        ], factory );
    } else {

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

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

    $.widget("mjs.nestedSortable", $.extend({}, $.ui.sortable.prototype, {

        options: {
            disableParentChange: false,
            doNotClear: false,
            expandOnHover: 700,
            isAllowed: function() { return true; },
            isTree: false,
            listType: "ol",
            maxLevels: 0,
            protectRoot: false,
            rootID: null,
            rtl: false,
            startCollapsed: false,
            tabSize: 20,

            branchClass: "mjs-nestedSortable-branch",
            collapsedClass: "mjs-nestedSortable-collapsed",
            disableNestingClass: "mjs-nestedSortable-no-nesting",
            errorClass: "mjs-nestedSortable-error",
            expandedClass: "mjs-nestedSortable-expanded",
            hoveringClass: "mjs-nestedSortable-hovering",
            leafClass: "mjs-nestedSortable-leaf",
            disabledClass: "mjs-nestedSortable-disabled"
        },

        _create: function() {
            var self = this,
                err;

            this.element.data("ui-sortable", this.element.data("mjs-nestedSortable"));

            // mjs - prevent browser from freezing if the HTML is not correct
            if (!this.element.is(this.options.listType)) {
                err = "nestedSortable: " +
                    "Please check that the listType option is set to your actual list type";

                throw new Error(err);
            }

            // if we have a tree with expanding/collapsing functionality,
            // force 'intersect' tolerance method
            if (this.options.isTree && this.options.expandOnHover) {
                this.options.tolerance = "intersect";
            }

            $.ui.sortable.prototype._create.apply(this, arguments);

            // prepare the tree by applying the right classes
            // (the CSS is responsible for actual hide/show functionality)
            if (this.options.isTree) {
                $(this.items).each(function() {
                    var $li = this.item,
                        hasCollapsedClass = $li.hasClass(self.options.collapsedClass),
                        hasExpandedClass = $li.hasClass(self.options.expandedClass);

                    if ($li.children(self.options.listType).length) {
                        $li.addClass(self.options.branchClass);
                        // expand/collapse class only if they have children

                        if ( !hasCollapsedClass && !hasExpandedClass ) {
                            if (self.options.startCollapsed) {
                                $li.addClass(self.options.collapsedClass);
                            } else {
                                $li.addClass(self.options.expandedClass);
                            }
                        }
                    } else {
                        $li.addClass(self.options.leafClass);
                    }
                });
            }
        },

        _destroy: function() {
            this.element
                .removeData("mjs-nestedSortable")
                .removeData("ui-sortable");
            return $.ui.sortable.prototype._destroy.apply(this, arguments);
        },

        _mouseDrag: function(event) {
            var i,
                item,
                itemElement,
                intersection,
                self = this,
                o = this.options,
                scrolled = false,
                $document = $(document),
                previousTopOffset,
                parentItem,
                level,
                childLevels,
                itemAfter,
                itemBefore,
                newList,
                method,
                a,
                previousItem,
                nextItem,
                helperIsNotSibling;

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

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

                } else {

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

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

                }

                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");

            // mjs - find the top offset before rearrangement,
            previousTopOffset = this.placeholder.offset().top;

            //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 + window.scrollY) + "px";
                this.helper[0].style.top = this.position.top + "px"; // @Modified by Tobias Hößl; wrong positioning otherwise when scrolled down
            }

            // mjs - check and reset hovering state at each cycle
            this.hovering = this.hovering ? this.hovering : null;
            this.mouseentered = this.mouseentered ? this.mouseentered : false;

            // mjs - let's start caching some variables
            (function() {
                var _parentItem = this.placeholder.parent().parent();
                if (_parentItem && _parentItem.closest(".ui-sortable").length) {
                    parentItem = _parentItem;
                }
            }.call(this));

            level = this._getLevel(this.placeholder);
            childLevels = this._getChildLevels(this.helper);
            newList = document.createElement(o.listType);

            //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;
                }

                // No action if intersected item is disabled
                // and the element above or below in the direction we're going is also disabled
                if (itemElement.className.indexOf(o.disabledClass) !== -1) {
                    // Note: intersection hardcoded direction values from
                    // jquery.ui.sortable.js:_intersectsWithPointer
                    if (intersection === 2) {
                        // Going down
                        itemAfter = this.items[i + 1];
                        if (itemAfter && itemAfter.item.hasClass(o.disabledClass)) {
                            continue;
                        }

                    } else if (intersection === 1) {
                        // Going up
                        itemBefore = this.items[i - 1];
                        if (itemBefore && itemBefore.item.hasClass(o.disabledClass)) {
                            continue;
                        }
                    }
                }

                method = intersection === 1 ? "next" : "prev";

                // 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[method]()[0] !== itemElement &&
                    !$.contains(this.placeholder[0], itemElement) &&
                    (
                        this.options.type === "semi-dynamic" ?
                            !$.contains(this.element[0], itemElement) :
                            true
                    )
                ) {

                    // mjs - we are intersecting an element:
                    // trigger the mouseenter event and store this state
                    if (!this.mouseentered) {
                        $(itemElement).mouseenter();
                        this.mouseentered = true;
                    }

                    // mjs - if the element has children and they are hidden,
                    // show them after a delay (CSS responsible)
                    if (o.isTree && $(itemElement).hasClass(o.collapsedClass) && o.expandOnHover) {
                        if (!this.hovering) {
                            $(itemElement).addClass(o.hoveringClass);
                            this.hovering = window.setTimeout(function() {
                                $(itemElement)
                                    .removeClass(o.collapsedClass)
                                    .addClass(o.expandedClass);

                                self.refreshPositions();
                                self._trigger("expand", event, self._uiHash());
                            }, o.expandOnHover);
                        }
                    }

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

                    // mjs - rearrange the elements and reset timeouts and hovering state
                    if (this.options.tolerance === "pointer" || this._intersectsWithSides(item)) {
                        $(itemElement).mouseleave();
                        this.mouseentered = false;
                        $(itemElement).removeClass(o.hoveringClass);
                        if (this.hovering) {
                            window.clearTimeout(this.hovering);
                        }
                        this.hovering = null;

                        // mjs - do not switch container if
                        // it's a root item and 'protectRoot' is true
                        // or if it's not a root item but we are trying to make it root
                        if (o.protectRoot &&
                            !(
                                this.currentItem[0].parentNode === this.element[0] &&
                                    // it's a root item
                                itemElement.parentNode !== this.element[0]
                                // it's intersecting a non-root item
                            )
                        ) {
                            if (this.currentItem[0].parentNode !== this.element[0] &&
                                itemElement.parentNode === this.element[0]
                            ) {

                                if ( !$(itemElement).children(o.listType).length) {
                                    itemElement.appendChild(newList);
                                    if (o.isTree) {
                                        $(itemElement)
                                            .removeClass(o.leafClass)
                                            .addClass(o.branchClass + " " + o.expandedClass);
                                    }
                                }

                                if (this.direction === "down") {
                                    a = $(itemElement).prev().children(o.listType);
                                } else {
                                    a = $(itemElement).children(o.listType);
                                }

                                if (a[0] !== undefined) {
                                    this._rearrange(event, null, a);
                                }

                            } else {
                                this._rearrange(event, item);
                            }
                        } else if (!o.protectRoot) {
                            this._rearrange(event, item);
                        }
                    } else {
                        break;
                    }

                    // Clear emtpy ul's/ol's
                    this._clearEmpty(itemElement);

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

            // mjs - to find the previous sibling in the list,
            // keep backtracking until we hit a valid list item.
            (function() {
                var _previousItem = this.placeholder.prev();
                if (_previousItem.length) {
                    previousItem = _previousItem;
                } else {
                    previousItem = null;
                }
            }.call(this));

            if (previousItem != null) {
                while (
                previousItem[0].nodeName.toLowerCase() !== "li" ||
                previousItem[0].className.indexOf(o.disabledClass) !== -1 ||
                previousItem[0] === this.currentItem[0] ||
                previousItem[0] === this.helper[0]
                    ) {
                    if (previousItem[0].previousSibling) {
                        previousItem = $(previousItem[0].previousSibling);
                    } else {
                        previousItem = null;
                        break;
                    }
                }
            }

            // mjs - to find the next sibling in the list,
            // keep stepping forward until we hit a valid list item.
            (function() {
                var _nextItem = this.placeholder.next();
                if (_nextItem.length) {
                    nextItem = _nextItem;
                } else {
                    nextItem = null;
                }
            }.call(this));

            if (nextItem != null) {
                while (
                nextItem[0].nodeName.toLowerCase() !== "li" ||
                nextItem[0].className.indexOf(o.disabledClass) !== -1 ||
                nextItem[0] === this.currentItem[0] ||
                nextItem[0] === this.helper[0]
                    ) {
                    if (nextItem[0].nextSibling) {
                        nextItem = $(nextItem[0].nextSibling);
                    } else {
                        nextItem = null;
                        break;
                    }
                }
            }

            this.beyondMaxLevels = 0;

            // mjs - if the item is moved to the left, send it one level up
            // but only if it's at the bottom of the list
            if (parentItem != null &&
                nextItem == null &&
                !(o.protectRoot && parentItem[0].parentNode == this.element[0]) &&
                (
                    o.rtl &&
                    (
                        this.positionAbs.left +
                        this.helper.outerWidth() > parentItem.offset().left +
                        parentItem.outerWidth()
                    ) ||
                    !o.rtl && (this.positionAbs.left < parentItem.offset().left)
                )
            ) {

                parentItem.after(this.placeholder[0]);
                helperIsNotSibling = !parentItem
                    .children(o.listItem)
                    .children("li:visible:not(.ui-sortable-helper)")
                    .length;
                if (o.isTree && helperIsNotSibling) {
                    parentItem
                        .removeClass(this.options.branchClass + " " + this.options.expandedClass)
                        .addClass(this.options.leafClass);
                }
                if(typeof parentItem !== 'undefined')
                    this._clearEmpty(parentItem[0]);
                this._trigger("change", event, this._uiHash());
                // mjs - if the item is below a sibling and is moved to the right,
                // make it a child of that sibling
            } else if (previousItem != null &&
                !previousItem.hasClass(o.disableNestingClass) &&
                (
                    previousItem.children(o.listType).length &&
                    previousItem.children(o.listType).is(":visible") ||
                    !previousItem.children(o.listType).length
                ) &&
                !(o.protectRoot && this.currentItem[0].parentNode === this.element[0]) &&
                (
                    o.rtl &&
                    (
                        this.positionAbs.left +
                        this.helper.outerWidth() <
                        previousItem.offset().left +
                        previousItem.outerWidth() -
                        o.tabSize
                    ) ||
                    !o.rtl &&
                    (this.positionAbs.left > previousItem.offset().left + o.tabSize)
                )
            ) {

                this._isAllowed(previousItem, level, level + childLevels + 1);

                if (!previousItem.children(o.listType).length) {
                    previousItem[0].appendChild(newList);
                    if (o.isTree) {
                        previousItem
                            .removeClass(o.leafClass)
                            .addClass(o.branchClass + " " + o.expandedClass);
                    }
                }

                // mjs - if this item is being moved from the top, add it to the top of the list.
                if (previousTopOffset && (previousTopOffset <= previousItem.offset().top)) {
                    previousItem.children(o.listType).prepend(this.placeholder);
                } else {
                    // mjs - otherwise, add it to the bottom of the list.
                    previousItem.children(o.listType)[0].appendChild(this.placeholder[0]);
                }
                if(typeof parentItem !== 'undefined')
                    this._clearEmpty(parentItem[0]);
                this._trigger("change", event, this._uiHash());
            } else {
                this._isAllowed(parentItem, level, level + childLevels);
            }

            //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) {
            // mjs - if the item is in a position not allowed, send it back
            if (this.beyondMaxLevels) {

                this.placeholder.removeClass(this.options.errorClass);

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

                this._trigger("revert", event, this._uiHash());

            }

            // mjs - clear the hovering timeout, just to be sure
            $("." + this.options.hoveringClass)
                .mouseleave()
                .removeClass(this.options.hoveringClass);

            this.mouseentered = false;
            if (this.hovering) {
                window.clearTimeout(this.hovering);
            }
            this.hovering = null;

            this._relocate_event = event;
            this._pid_current = $(this.domPosition.parent).parent().attr("id");
            this._sort_current = this.domPosition.prev ? $(this.domPosition.prev).next().index() : 0;
            $.ui.sortable.prototype._mouseStop.apply(this, arguments); //asybnchronous execution, @see _clear for the relocate event.
        },

        // mjs - this function is slightly modified
        // to make it easier to hover over a collapsed element and have it expand
        _intersectsWithSides: function(item) {

            var half = this.options.isTree ? .8 : .5,
                isOverBottomHalf = isOverAxis(
                    this.positionAbs.top + this.offset.click.top,
                    item.top + (item.height * half),
                    item.height
                ),
                isOverTopHalf = isOverAxis(
                    this.positionAbs.top + this.offset.click.top,
                    item.top - (item.height * half),
                    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" && isOverTopHalf)
                    );
            }

        },

        _contactContainers: function() {

            if (this.options.protectRoot && this.currentItem[0].parentNode === this.element[0] ) {
                return;
            }

            $.ui.sortable.prototype._contactContainers.apply(this, arguments);

        },

        _clear: function() {
            var i,
                item;

            $.ui.sortable.prototype._clear.apply(this, arguments);

            //relocate event
            if (!(this._pid_current === this._uiHash().item.parent().parent().attr("id") &&
                this._sort_current === this._uiHash().item.index())) {
                this._trigger("relocate", this._relocate_event, this._uiHash());
            }

            // mjs - clean last empty ul/ol
            for (i = this.items.length - 1; i >= 0; i--) {
                item = this.items[i].item[0];
                this._clearEmpty(item);
            }

        },

        serialize: function(options) {

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

            $(items).each(function() {
                var res = ($(o.item || this).attr(o.attribute || "id") || "")
                        .match(o.expression || (/(.+)[-=_](.+)/)),
                    pid = ($(o.item || this).parent(o.listType)
                        .parent(o.items)
                        .attr(o.attribute || "id") || "")
                        .match(o.expression || (/(.+)[-=_](.+)/));

                if (res) {
                    str.push(
                        (
                            (o.key || res[1]) +
                            "[" +
                            (o.key && o.expression ? res[1] : res[2]) + "]"
                        ) +
                        "=" +
                        (pid ? (o.key && o.expression ? pid[1] : pid[2]) : o.rootID));
                }
            });

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

            return str.join("&");

        },

        toHierarchy: function(options) {

            var o = $.extend({}, this.options, options),
                ret = [];

            $(this.element).children(o.items).each(function() {
                var level = _recursiveItems(this);
                ret.push(level);
            });

            return ret;

            function _recursiveItems(item) {
                var id = ($(item).attr(o.attribute || "id") || "").match(o.expression || (/(.+)[-=_](.+)/)),
                    currentItem;
                if (id) {
                    currentItem = {
                        "id": id[2]
                    };

                    if ($(item).children(o.listType).children(o.items).length > 0) {
                        currentItem.children = [];
                        $(item).children(o.listType).children(o.items).each(function() {
                            var level = _recursiveItems(this);
                            currentItem.children.push(level);
                        });
                    }
                    return currentItem;
                }
            }
        },

        toArray: function(options) {

            var o = $.extend({}, this.options, options),
                sDepth = o.startDepthCount || 0,
                ret = [],
                left = 1;

            if (!o.excludeRoot) {
                ret.push({
                    "item_id": o.rootID,
                    "parent_id": null,
                    "depth": sDepth,
                    "left": left,
                    "right": ($(o.items, this.element).length + 1) * 2
                });
                left++;
            }

            $(this.element).children(o.items).each(function() {
                left = _recursiveArray(this, sDepth + 1, left);
            });

            ret = ret.sort(function(a, b) { return (a.left - b.left); });

            return ret;

            function _recursiveArray(item, depth, _left) {

                var right = _left + 1,
                    id,
                    pid,
                    parentItem;

                if ($(item).children(o.listType).children(o.items).length > 0) {
                    depth++;
                    $(item).children(o.listType).children(o.items).each(function() {
                        right = _recursiveArray($(this), depth, right);
                    });
                    depth--;
                }

                id = ($(item).attr(o.attribute || "id")).match(o.expression || (/(.+)[-=_](.+)/));

                if (depth === sDepth + 1) {
                    pid = o.rootID;
                } else {
                    parentItem = ($(item).parent(o.listType)
                        .parent(o.items)
                        .attr(o.attribute || "id"))
                        .match(o.expression || (/(.+)[-=_](.+)/));
                    pid = parentItem[2];
                }

                if (id) {
                    ret.push({
                        "item_id": id[2],
                        "parent_id": pid,
                        "depth": depth,
                        "left": _left,
                        "right": right
                    });
                }

                _left = right + 1;
                return _left;
            }

        },

        _clearEmpty: function (item) {
            function replaceClass(elem, search, replace, swap) {
                if (swap) {
                    search = [replace, replace = search][0];
                }

                $(elem).removeClass(search).addClass(replace);
            }

            var o = this.options,
                childrenList = $(item).children(o.listType),
                hasChildren = childrenList.is(':not(:empty)');

            var doNotClear =
                o.doNotClear ||
                hasChildren ||
                o.protectRoot && $(item)[0] === this.element[0];

            if (o.isTree) {
                replaceClass(item, o.branchClass, o.leafClass, doNotClear);

                if (doNotClear && hasChildren) {
                    replaceClass(item, o.collapsedClass, o.expandedClass);
                }
            }

            if (!doNotClear) {
                childrenList.remove();
            }
        },

        _getLevel: function(item) {

            var level = 1,
                list;

            if (this.options.listType) {
                list = item.closest(this.options.listType);
                while (list && list.length > 0 && !list.is(".ui-sortable")) {
                    level++;
                    list = list.parent().closest(this.options.listType);
                }
            }

            return level;
        },

        _getChildLevels: function(parent, depth) {
            var self = this,
                o = this.options,
                result = 0;
            depth = depth || 0;

            $(parent).children(o.listType).children(o.items).each(function(index, child) {
                result = Math.max(self._getChildLevels(child, depth + 1), result);
            });

            return depth ? result + 1 : result;
        },

        _isAllowed: function(parentItem, level, levels) {
            var o = this.options,
            // this takes into account the maxLevels set to the recipient list
                maxLevels = this
                    .placeholder
                    .closest(".ui-sortable")
                    .nestedSortable("option", "maxLevels"),

            // Check if the parent has changed to prevent it, when o.disableParentChange is true
                oldParent = this.currentItem.parent().parent(),
                disabledByParentchange = o.disableParentChange && (
                        //From somewhere to somewhere else, except the root
                        typeof parentItem !== 'undefined' && !oldParent.is(parentItem) ||
                        typeof parentItem === 'undefined' && oldParent.is("li")	//From somewhere to the root
                    );
            // mjs - is the root protected?
            // mjs - are we nesting too deep?
            if (
                disabledByParentchange ||
                !o.isAllowed(this.placeholder, parentItem, this.currentItem)
            ) {
                this.placeholder.addClass(o.errorClass);
                if (maxLevels < levels && maxLevels !== 0) {
                    this.beyondMaxLevels = levels - maxLevels;
                } else {
                    this.beyondMaxLevels = 1;
                }
            } else {
                if (maxLevels < levels && maxLevels !== 0) {
                    this.placeholder.addClass(o.errorClass);
                    this.beyondMaxLevels = levels - maxLevels;
                } else {
                    this.placeholder.removeClass(o.errorClass);
                    this.beyondMaxLevels = 0;
                }
            }
        }

    }));

    $.mjs.nestedSortable.prototype.options = $.extend(
        {},
        $.ui.sortable.prototype.options,
        $.mjs.nestedSortable.prototype.options
    );
}));