/*
 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: '='
                },
                link: function(scope, element, attrs, ngModel) {
                    var savedNodes;

                    function combineCallbacks(first, second){
                        var firstIsFunc = first && (typeof first === 'function');
                        var secondIsFunc = second && (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) {
                            if (key === 'items') {
                                value = uiSortableConfig.items;
                            } else if (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)
                            // is placed last.
                            result = savedNodes.last();
                        }
                        return result;
                    }

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

                    function getElementScope(elementScopes, element) {
                        var result = null;
                        for (var i = 0; i < elementScopes.length; i++) {
                            var x = elementScopes[i];
                            if (x.element[0] === element[0]) {
                                result = x.scope;
                                break;
                            }
                        }
                        return result;
                    }

                    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(ui) {
                        return ui.item.parent()
                            .find(opts['ui-model-items'])
                            .index(ui.item);
                    }

                    var opts = {};

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

                    var callbacks = {
                        receive: null,
                        remove: null,
                        start: null,
                        stop: null,
                        update: 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);
                            ui.item.sortable = {
                                model: ngModel.$modelValue[index],
                                index: index,
                                source: ui.item.parent(),
                                sourceModel: ngModel.$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;
                                    });
                                }
                            };
                        };

                        callbacks.activate = function(e, ui) {
                            // 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 = element.contents();

                            // 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);
                            }

                            // save the directive's scope so that it is accessible from ui.item.sortable
                            var connectedSortables = ui.item.sortable._connectedSortables || [];

                            connectedSortables.push({
                                element: element,
                                scope: scope
                            });

                            ui.item.sortable._connectedSortables = connectedSortables;
                        };

                        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);
                                var droptarget = ui.item.parent();
                                ui.item.sortable.droptarget = droptarget;

                                var droptargetScope = getElementScope(ui.item.sortable._connectedSortables, droptarget);
                                ui.item.sortable.droptargetModel = droptargetScope.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);
                            }
                            savedNodes.appendTo(element);

                            // 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);
                                });
                            }
                        };

                        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.
                            if(!ui.item.sortable.received &&
                                ('dropindex' in ui.item.sortable) &&
                                !ui.item.sortable.isCanceled()) {

                                scope.$apply(function () {
                                    ngModel.$modelValue.splice(
                                        ui.item.sortable.dropindex, 0,
                                        ngModel.$modelValue.splice(ui.item.sortable.index, 1)[0]);
                                });
                            } else {
                                // if the item was not moved, then restore the elements
                                // so that the ngRepeat's comment are correct.
                                if ((!('dropindex' in ui.item.sortable) || ui.item.sortable.isCanceled()) &&
                                    !angular.equals(element.contents(), savedNodes)) {

                                    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);
                                    }
                                    savedNodes.appendTo(element);
                                }
                            }

                            // It's now safe to clear the savedNodes
                            // since stop is the last callback.
                            savedNodes = 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];
                                });
                            }
                        };

                        wrappers.helper = function (inner) {
                            if (inner && typeof inner === 'function') {
                                return function (e, item) {
                                    var innerResult = inner.apply(this, arguments);
                                    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);
                    }
                }
            };
        }
    ]);