/*
 jQuery UI Sortable plugin wrapper

 @param [ui-sortable] {object} Options to pass to $.fn.sortable() merged onto ui.config
 */
angular.module('ui.sortable', [])
  .value('uiSortableConfig',{
    // the default for jquery-ui sortable is "> *", we need to restrict this to
    // ng-repeat items
    // if the user uses
    items: '> [ng-repeat],> [data-ng-repeat],> [x-ng-repeat]'
  })
  .directive('uiSortable', [
    'uiSortableConfig', '$timeout', '$log',
    function(uiSortableConfig, $timeout, $log) {
      return {
        require:'?ngModel',
        scope: {
          ngModel:'=',
          uiSortable:'=',
          ////Expression bindings from html.
          create:'&uiSortableCreate',
          // helper:'&uiSortableHelper',
          start:'&uiSortableStart',
          activate:'&uiSortableActivate',
          // sort:'&uiSortableSort',
          // change:'&uiSortableChange',
          // over:'&uiSortableOver',
          // out:'&uiSortableOut',
          beforeStop:'&uiSortableBeforeStop',
          update:'&uiSortableUpdate',
          remove:'&uiSortableRemove',
          receive:'&uiSortableReceive',
          deactivate:'&uiSortableDeactivate',
          stop:'&uiSortableStop'
        },
        link: function(scope, element, attrs, ngModel) {
          var savedNodes;
          var helper;

          function combineCallbacks(first, second){
            var firstIsFunc = typeof first === 'function';
            var secondIsFunc = typeof second === 'function';
            if(firstIsFunc && secondIsFunc) {
              return function() {
                first.apply(this, arguments);
                second.apply(this, arguments);
              };
            } else if (secondIsFunc) {
              return second;
            }
            return first;
          }

          function getSortableWidgetInstance(element) {
            // this is a fix to support jquery-ui prior to v1.11.x
            // otherwise we should be using `element.sortable('instance')`
            var data = element.data('ui-sortable');
            if (data && typeof data === 'object' && data.widgetFullName === 'ui-sortable') {
              return data;
            }
            return null;
          }

          function patchSortableOption(key, value) {
            if (callbacks[key]) {
              if( key === 'stop' ){
                // call apply after stop
                value = combineCallbacks(
                  value, function() { scope.$apply(); });

                value = combineCallbacks(value, afterStop);
              }
              // wrap the callback
              value = combineCallbacks(callbacks[key], value);
            } else if (wrappers[key]) {
              value = wrappers[key](value);
            }

            // patch the options that need to have values set
            if (!value && (key === 'items' || key === 'ui-model-items')) {
              value = uiSortableConfig.items;
            }

            return value;
          }

          function patchUISortableOptions(newVal, oldVal, sortableWidgetInstance) {
            function addDummyOptionKey(value, key) {
              if (!(key in opts)) {
                // add the key in the opts object so that
                // the patch function detects and handles it
                opts[key] = null;
              }
            }
            // for this directive to work we have to attach some callbacks
            angular.forEach(callbacks, addDummyOptionKey);

            // only initialize it in case we have to
            // update some options of the sortable
            var optsDiff = null;

            if (oldVal) {
              // reset deleted options to default
              var defaultOptions;
              angular.forEach(oldVal, function(oldValue, key) {
                if (!newVal || !(key in newVal)) {
                  if (key in directiveOpts) {
                    if (key === 'ui-floating') {
                      opts[key] = 'auto';
                    } else {
                      opts[key] = patchSortableOption(key, undefined);
                    }
                    return;
                  }

                  if (!defaultOptions) {
                    defaultOptions = angular.element.ui.sortable().options;
                  }
                  var defaultValue = defaultOptions[key];
                  defaultValue = patchSortableOption(key, defaultValue);

                  if (!optsDiff) {
                    optsDiff = {};
                  }
                  optsDiff[key] = defaultValue;
                  opts[key] = defaultValue;
                }
              });
            }

            // update changed options
            angular.forEach(newVal, function(value, key) {
              // if it's a custom option of the directive,
              // handle it approprietly
              if (key in directiveOpts) {
                if (key === 'ui-floating' && (value === false || value === true) && sortableWidgetInstance) {
                  sortableWidgetInstance.floating = value;
                }

                opts[key] = patchSortableOption(key, value);
                return;
              }

              value = patchSortableOption(key, value);

              if (!optsDiff) {
                optsDiff = {};
              }
              optsDiff[key] = value;
              opts[key] = value;
            });

            return optsDiff;
          }

          function getPlaceholderElement (element) {
            var placeholder = element.sortable('option','placeholder');

            // placeholder.element will be a function if the placeholder, has
            // been created (placeholder will be an object).  If it hasn't
            // been created, either placeholder will be false if no
            // placeholder class was given or placeholder.element will be
            // undefined if a class was given (placeholder will be a string)
            if (placeholder && placeholder.element && typeof placeholder.element === 'function') {
              var result = placeholder.element();
              // workaround for jquery ui 1.9.x,
              // not returning jquery collection
              result = angular.element(result);
              return result;
            }
            return null;
          }

          function getPlaceholderExcludesludes (element, placeholder) {
            // exact match with the placeholder's class attribute to handle
            // the case that multiple connected sortables exist and
            // the placeholder option equals the class of sortable items
            var notCssSelector = opts['ui-model-items'].replace(/[^,]*>/g, '');
            var excludes = element.find('[class="' + placeholder.attr('class') + '"]:not(' + notCssSelector + ')');
            return excludes;
          }

          function hasSortingHelper (element, ui) {
            var helperOption = element.sortable('option','helper');
            return helperOption === 'clone' || (typeof helperOption === 'function' && ui.item.sortable.isCustomHelperUsed());
          }

          function getSortingHelper (element, ui/*, savedNodes*/) {
            var result = null;
            if (hasSortingHelper(element, ui) &&
                element.sortable( 'option', 'appendTo' ) === 'parent') {
              // The .ui-sortable-helper element (that's the default class name)
              result = helper;
            }
            return result;
          }

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

          function getElementContext(elementScopes, element) {
            for (var i = 0; i < elementScopes.length; i++) {
              var c = elementScopes[i];
              if (c.element[0] === element[0]) {
                return c;
              }
            }
          }

          function afterStop(e, ui) {
            ui.item.sortable._destroy();
          }

          // return the index of ui.item among the items
          // we can't just do ui.item.index() because there it might have siblings
          // which are not items
          function getItemIndex(item) {
            return item.parent()
              .find(opts['ui-model-items'])
              .index(item);
          }

          var opts = {};

          // directive specific options
          var directiveOpts = {
            'ui-floating': undefined,
            'ui-model-items': uiSortableConfig.items
          };

          var callbacks = {
            create: null,
            start: null,
            activate: null,
            // sort: null,
            // change: null,
            // over: null,
            // out: null,
            beforeStop: null,
            update: null,
            remove: null,
            receive: null,
            deactivate: null,
            stop: null
          };

          var wrappers = {
            helper: null
          };

          angular.extend(opts, directiveOpts, uiSortableConfig, scope.uiSortable);

          if (!angular.element.fn || !angular.element.fn.jquery) {
            $log.error('ui.sortable: jQuery should be included before AngularJS!');
            return;
          }

          function wireUp () {
            // When we add or remove elements, we need the sortable to 'refresh'
            // so it can find the new/removed elements.
            scope.$watchCollection('ngModel', function() {
              // Timeout to let ng-repeat modify the DOM
              $timeout(function() {
                // ensure that the jquery-ui-sortable widget instance
                // is still bound to the directive's element
                if (!!getSortableWidgetInstance(element)) {
                  element.sortable('refresh');
                }
              }, 0, false);
            });

            callbacks.start = function(e, ui) {
              if (opts['ui-floating'] === 'auto') {
                // since the drag has started, the element will be
                // absolutely positioned, so we check its siblings
                var siblings = ui.item.siblings();
                var sortableWidgetInstance = getSortableWidgetInstance(angular.element(e.target));
                sortableWidgetInstance.floating = isFloating(siblings);
              }

              // Save the starting position of dragged item
              var index = getItemIndex(ui.item);
              ui.item.sortable = {
                model: ngModel.$modelValue[index],
                index: index,
                source: element,
                sourceList: ui.item.parent(),
                sourceModel: ngModel.$modelValue,
                cancel: function () {
                  ui.item.sortable._isCanceled = true;
                },
                isCanceled: function () {
                  return ui.item.sortable._isCanceled;
                },
                isCustomHelperUsed: function () {
                  return !!ui.item.sortable._isCustomHelperUsed;
                },
                _isCanceled: false,
                _isCustomHelperUsed: ui.item.sortable._isCustomHelperUsed,
                _destroy: function () {
                  angular.forEach(ui.item.sortable, function(value, key) {
                    ui.item.sortable[key] = undefined;
                  });
                },
                _connectedSortables: [],
                _getElementContext: function (element) {
                  return getElementContext(this._connectedSortables, element);
                }
              };
            };

            callbacks.activate = function(e, ui) {
              var isSourceContext = ui.item.sortable.source === element;
              var savedNodesOrigin = isSourceContext ?
                                     ui.item.sortable.sourceList :
                                     element;
              var elementContext = {
                element: element,
                scope: scope,
                isSourceContext: isSourceContext,
                savedNodesOrigin: savedNodesOrigin
              };
              // save the directive's scope so that it is accessible from ui.item.sortable
              ui.item.sortable._connectedSortables.push(elementContext);

              // We need to make a copy of the current element's contents so
              // we can restore it after sortable has messed it up.
              // This is inside activate (instead of start) in order to save
              // both lists when dragging between connected lists.
              savedNodes = savedNodesOrigin.contents();
              helper = ui.helper;

              // If this list has a placeholder (the connected lists won't),
              // don't inlcude it in saved nodes.
              var placeholder = getPlaceholderElement(element);
              if (placeholder && placeholder.length) {
                var excludes = getPlaceholderExcludesludes(element, placeholder);
                savedNodes = savedNodes.not(excludes);
              }
            };

            callbacks.update = function(e, ui) {
              // Save current drop position but only if this is not a second
              // update that happens when moving between lists because then
              // the value will be overwritten with the old value
              if (!ui.item.sortable.received) {
                ui.item.sortable.dropindex = getItemIndex(ui.item);
                var droptarget = ui.item.closest('[ui-sortable], [data-ui-sortable], [x-ui-sortable]');
                ui.item.sortable.droptarget = droptarget;
                ui.item.sortable.droptargetList = ui.item.parent();

                var droptargetContext = ui.item.sortable._getElementContext(droptarget);
                ui.item.sortable.droptargetModel = droptargetContext.scope.ngModel;

                // Cancel the sort (let ng-repeat do the sort for us)
                // Don't cancel if this is the received list because it has
                // already been canceled in the other list, and trying to cancel
                // here will mess up the DOM.
                element.sortable('cancel');
              }

              // Put the nodes back exactly the way they started (this is very
              // important because ng-repeat uses comment elements to delineate
              // the start and stop of repeat sections and sortable doesn't
              // respect their order (even if we cancel, the order of the
              // comments are still messed up).
              var sortingHelper = !ui.item.sortable.received && getSortingHelper(element, ui, savedNodes);
              if (sortingHelper && sortingHelper.length) {
                // Restore all the savedNodes except from the sorting helper element.
                // That way it will be garbage collected.
                savedNodes = savedNodes.not(sortingHelper);
              }
              var elementContext = ui.item.sortable._getElementContext(element);
              savedNodes.appendTo(elementContext.savedNodesOrigin);

              // If this is the target connected list then
              // it's safe to clear the restored nodes since:
              // update is currently running and
              // stop is not called for the target list.
              if (ui.item.sortable.received) {
                savedNodes = null;
              }

              // If received is true (an item was dropped in from another list)
              // then we add the new item to this list otherwise wait until the
              // stop event where we will know if it was a sort or item was
              // moved here from another list
              if (ui.item.sortable.received && !ui.item.sortable.isCanceled()) {
                scope.$apply(function () {
                  ngModel.$modelValue.splice(ui.item.sortable.dropindex, 0,
                                             ui.item.sortable.moved);
                });
                scope.$emit('ui-sortable:moved', ui);
              }
            };

            callbacks.stop = function(e, ui) {
              // If the received flag hasn't be set on the item, this is a
              // normal sort, if dropindex is set, the item was moved, so move
              // the items in the list.
              var wasMoved = ('dropindex' in ui.item.sortable) &&
                              !ui.item.sortable.isCanceled();

              if (wasMoved && !ui.item.sortable.received) {

                scope.$apply(function () {
                  ngModel.$modelValue.splice(
                    ui.item.sortable.dropindex, 0,
                    ngModel.$modelValue.splice(ui.item.sortable.index, 1)[0]);
                });
                scope.$emit('ui-sortable:moved', ui);
              } else if (!wasMoved &&
                         !angular.equals(element.contents().toArray(), savedNodes.toArray())) {
                // if the item was not moved
                // and the DOM element order has changed,
                // then restore the elements
                // so that the ngRepeat's comment are correct.

                var sortingHelper = getSortingHelper(element, ui, savedNodes);
                if (sortingHelper && sortingHelper.length) {
                  // Restore all the savedNodes except from the sorting helper element.
                  // That way it will be garbage collected.
                  savedNodes = savedNodes.not(sortingHelper);
                }
                var elementContext = ui.item.sortable._getElementContext(element);
                savedNodes.appendTo(elementContext.savedNodesOrigin);
              }

              // It's now safe to clear the savedNodes and helper
              // since stop is the last callback.
              savedNodes = null;
              helper = null;
            };

            callbacks.receive = function(e, ui) {
              // An item was dropped here from another list, set a flag on the
              // item.
              ui.item.sortable.received = true;
            };

            callbacks.remove = function(e, ui) {
              // Workaround for a problem observed in nested connected lists.
              // There should be an 'update' event before 'remove' when moving
              // elements. If the event did not fire, cancel sorting.
              if (!('dropindex' in ui.item.sortable)) {
                element.sortable('cancel');
                ui.item.sortable.cancel();
              }

              // Remove the item from this list's model and copy data into item,
              // so the next list can retrive it
              if (!ui.item.sortable.isCanceled()) {
                scope.$apply(function () {
                  ui.item.sortable.moved = ngModel.$modelValue.splice(
                    ui.item.sortable.index, 1)[0];
                });
              }
            };

            // setup attribute handlers
            angular.forEach(callbacks, function(value, key) {
              callbacks[key] = combineCallbacks(callbacks[key],
                function () {
                  var attrHandler = scope[key];
                  var attrHandlerFn;
                  if (typeof attrHandler === 'function' &&
                      ('uiSortable' + key.substring(0,1).toUpperCase() + key.substring(1)).length &&
                      typeof (attrHandlerFn = attrHandler()) === 'function') {
                    attrHandlerFn.apply(this, arguments);
                  }
                });
            });


            wrappers.helper = function (inner) {
              if (inner && typeof inner === 'function') {
                return function (e, item) {
                  var oldItemSortable = item.sortable;
                  var index = getItemIndex(item);
                  item.sortable = {
                    model: ngModel.$modelValue[index],
                    index: index,
                    source: element,
                    sourceList: item.parent(),
                    sourceModel: ngModel.$modelValue,
                    _restore: function () {
                      angular.forEach(item.sortable, function(value, key) {
                        item.sortable[key] = undefined;
                      });

                      item.sortable = oldItemSortable;
                    }
                  };

                  var innerResult = inner.apply(this, arguments);
                  item.sortable._restore();
                  item.sortable._isCustomHelperUsed = item !== innerResult;
                  return innerResult;
                };
              }
              return inner;
            };

            scope.$watchCollection('uiSortable', function(newVal, oldVal) {
              // ensure that the jquery-ui-sortable widget instance
              // is still bound to the directive's element
              var sortableWidgetInstance = getSortableWidgetInstance(element);
              if (!!sortableWidgetInstance) {
                var optsDiff = patchUISortableOptions(newVal, oldVal, sortableWidgetInstance);

                if (optsDiff) {
                  element.sortable('option', optsDiff);
                }
              }
            }, true);

            patchUISortableOptions(opts);
          }

          function init () {
            if (ngModel) {
              wireUp();
            } else {
              $log.info('ui.sortable: ngModel not provided!', element);
            }

            // Create sortable
            element.sortable(opts);
          }

          function initIfEnabled () {
            if (scope.uiSortable && scope.uiSortable.disabled) {
              return false;
            }

            init();

            // Stop Watcher
            initIfEnabled.cancelWatcher();
            initIfEnabled.cancelWatcher = angular.noop;

            return true;
          }

          initIfEnabled.cancelWatcher = angular.noop;

          if (!initIfEnabled()) {
            initIfEnabled.cancelWatcher = scope.$watch('uiSortable.disabled', initIfEnabled);
          }
        }
      };
    }
  ]);