import { getRequestErrorMessage } from 'ghost/utils/ajax';

var PostsController = Ember.ArrayController.extend({
    // this will cause the list to re-sort when any of these properties change on any of the models
    sortProperties: ['status', 'published_at', 'updated_at'],

    // override Ember.SortableMixin
    //
    // this function will keep the posts list sorted when loading individual/bulk
    // models from the server, even if records in between haven't been loaded.
    // this can happen when reloading the page on the Editor or PostsPost routes.
    //
    // a custom sort function is needed in order to sort the posts list the same way the server would:
    //     status: ASC
    //     published_at: DESC
    //     updated_at: DESC
    orderBy: function (item1, item2) {
        function publishedAtCompare() {
            var published1 = item1.get('published_at'),
                published2 = item2.get('published_at');

            if (!published1 && !published2) {
                return 0;
            }

            if (!published1 && published2) {
                return -1;
            }

            if (!published2 && published1) {
                return 1;
            }

            return Ember.compare(item1.get('published_at').valueOf(), item2.get('published_at').valueOf());
        }

        var updated1 = item1.get('updated_at'),
            updated2 = item2.get('updated_at'),
            statusResult,
            updatedAtResult,
            publishedAtResult;

        // when `updated_at` is undefined, the model is still
        // being written to with the results from the server
        if (item1.get('isNew') || !updated1) {
            return -1;
        }

        if (item2.get('isNew') || !updated2) {
            return 1;
        }

        statusResult = Ember.compare(item1.get('status'), item2.get('status'));
        updatedAtResult = Ember.compare(updated1.valueOf(), updated2.valueOf());
        publishedAtResult = publishedAtCompare();

        if (statusResult === 0) {
            if (publishedAtResult === 0) {
                // This should be DESC
                return updatedAtResult * -1;
            }
            // This should be DESC
            return publishedAtResult * -1;
        }

        return statusResult;
    },

    // set from PostsRoute
    paginationSettings: null,

    // holds the next page to load during infinite scroll
    nextPage: null,

    // indicates whether we're currently loading the next page
    isLoading: null,

    init: function () {
        this._super();

        var metadata = this.store.metadataFor('post');
        this.set('nextPage', metadata.pagination.next);
    },

    /**
     * Takes an ajax response, concatenates any error messages, then generates an error notification.
     * @param {jqXHR} response The jQuery ajax reponse object.
     * @return
     */
    reportLoadError: function (response) {
        var message = 'A problem was encountered while loading more posts';

        if (response) {
            // Get message from response
            message += ': ' + getRequestErrorMessage(response, true);
        } else {
            message += '.';
        }

        this.notifications.showError(message);
    },

    actions: {
        /**
        * Loads the next paginated page of posts into the ember-data store. Will cause the posts list UI to update.
        * @return
        */
        loadNextPage: function () {
            var self = this,
                store = this.get('store'),
                nextPage = this.get('nextPage'),
                paginationSettings = this.get('paginationSettings');

            if (nextPage) {
                this.set('isLoading', true);
                this.set('paginationSettings.page', nextPage);
                store.find('post', paginationSettings).then(function () {
                    var metadata = store.metadataFor('post');

                    self.set('nextPage', metadata.pagination.next);
                    self.set('isLoading', false);
                }, function (response) {
                    self.reportLoadError(response);
                });
            }
        }
    }
});

export default PostsController;