/*
 * jQuery UI Nested Sortable
 * v 1.3.5 / 21 jun 2012
 * http://mjsarfatti.com/code/nestedSortable
 *
 * Depends on:
 *   jquery.ui.sortable.js 1.8+
 *
 * Copyright (c) 2010-2012 Manuele J Sarfatti
 * Licensed under the MIT License
 * http://www.opensource.org/licenses/mit-license.php
 */

(function($) {

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

    options: {
      tabSize: 20,
      disableNesting: 'mjs-nestedSortable-no-nesting',
      errorClass: 'mjs-nestedSortable-error',
      listType: 'ol',
      maxLevels: 0,
      protectRoot: false,
      rootID: null,
      rtl: false,
      isAllowed: function(item, parent) { return true; }
    },

    _create: function() {
      this.element.data('sortable', this.element.data('nestedSortable'));

      if (!this.element.is(this.options.listType))
        throw new Error('nestedSortable: Please check the listType option is set to your actual list type');

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

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

    _mouseDrag: function(event) {

      //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) {
        var o = this.options, scrolled = false;
        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");

      // Find the top offset before rearrangement,
      var 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+'px';

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

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

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

          $(itemElement).mouseenter();

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

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

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

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

      var parentItem = (this.placeholder[0].parentNode.parentNode &&
               $(this.placeholder[0].parentNode.parentNode).closest('.ui-sortable').length)
                     ? $(this.placeholder[0].parentNode.parentNode)
                     : null,
          level = this._getLevel(this.placeholder),
          childLevels = this._getChildLevels(this.helper);

      // To find the previous sibling in the list, keep backtracking until we hit a valid list item.
      var previousItem = this.placeholder[0].previousSibling ? $(this.placeholder[0].previousSibling) : null;
      if (previousItem != null) {
        while (previousItem[0].nodeName.toLowerCase() != 'li' || previousItem[0] == this.currentItem[0] || previousItem[0] == this.helper[0]) {
          if (previousItem[0].previousSibling) {
            previousItem = $(previousItem[0].previousSibling);
          } else {
            previousItem = null;
            break;
          }
        }
      }

      // To find the next sibling in the list, keep stepping forward until we hit a valid list item.
      var nextItem = this.placeholder[0].nextSibling ? $(this.placeholder[0].nextSibling) : null;
      if (nextItem != null) {
        while (nextItem[0].nodeName.toLowerCase() != 'li' || nextItem[0] == this.currentItem[0] || nextItem[0] == this.helper[0]) {
          if (nextItem[0].nextSibling) {
            nextItem = $(nextItem[0].nextSibling);
          } else {
            nextItem = null;
            break;
          }
        }
      }

      var newList = document.createElement(o.listType);

      this.beyondMaxLevels = 0;
      
      // If the item is moved to the left, send it to its parent's level unless there are siblings below it.
      if (parentItem != null && nextItem == null &&
          (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]);
        this._clearEmpty(parentItem[0]);
        this._trigger("change", event, this._uiHash());
      }
      // If the item is below a sibling and is moved to the right, make it a child of that sibling.
      else if (previousItem != null &&
            (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 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);
        }
        // Otherwise, add it to the bottom of the list.
        else {
          previousItem.children(o.listType)[0].appendChild(this.placeholder[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, noPropagation) {

      // 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());

      }

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

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

    },

    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),
        sDepth = o.startDepthCount || 0,
          ret = [];

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

      return ret;

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

      ret.push({
        "item_id": o.rootID,
        "parent_id": 'none',
        "depth": sDepth,
        "left": '1',
        "right": ($(o.items, this.element).length + 1) * 2
      });

      $(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;

        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 {
          var 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) {

      var emptyList = $(item).children(this.options.listType);
      if (emptyList.length && !emptyList.children().length) {
        emptyList.remove();
      }

    },

    _getLevel: function(item) {

      var level = 1;

      if (this.options.listType) {
        var 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,
        isRoot = $(this.domPosition.parent).hasClass('ui-sortable') ? true : false,
        maxLevels = this.placeholder.closest('.ui-sortable').nestedSortable('option', 'maxLevels'); // this takes into account the maxLevels set to the recipient list

      // Is the root protected?
      // Are we trying to nest under a no-nest?
      // Are we nesting too deep?
      if (!o.isAllowed(parentItem, this.placeholder) ||
        parentItem && parentItem.hasClass(o.disableNesting) ||
        o.protectRoot && (parentItem == null && !isRoot || isRoot && level > 1)) {
          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);
})(jQuery);