define(
    [
        'jquery', 'backbone', 'underscore',
        'js/views/video/transcripts/utils',
        'js/views/metadata', 'js/collections/metadata',
        'js/views/video/transcripts/metadata_videolist'
    ],
    function($, Backbone, _, Utils, MetadataView, MetadataCollection) {
        var Editor = Backbone.View.extend({

            tagName: 'div',

            initialize: function() {
            // prepare data for MetadataView.Editor
                var metadata = this.$el.data('metadata'),
                    models = this.toModels(metadata);

                this.collection = new MetadataCollection(models);

                // initialize MetadataView.Editor
                this.settingsView = new MetadataView.Editor({
                    el: this.$el,
                    collection: this.collection
                });

                // Listen to edx_video_id update
                this.listenTo(Backbone, 'transcripts:basicTabUpdateEdxVideoId', this.handleUpdateEdxVideoId);

                // Listen to `video_url` and `edx_video_id` updates
                this.listenTo(Backbone, 'transcripts:basicTabFieldChanged', this.handleFieldChanged);

                // Listen to modal hidden event
                this.listenTo(Backbone, 'xblock:editorModalHidden', this.destroy);

                // Now `video_url` and `edx_video_id` viwes are rendered so
                // send a `check_transcript` request to get transctip status
                // This is needed because we need to update the transcrript status
                // when basic tabs renders. We trigger `basicTabFieldChanged` event
                // in `video_url` field but that event triggers before event is
                // actually binded
                this.handleFieldChanged();
            },

            /**
        * @function
        *
        * Convert JSON metadata to List of models
        *
        * @param {object|string} data Data containing information about metadata
        *                             setting editors.
        *
        * @returns {array} Processed objects list.
        *
        * @example:
        * var metadata = {
        *       field_1: {.1.},
        *       field_2: {.2.}
        *    };
        *
        * toModels(metadata) // => [{.1.}, {.2.}]
        *
        */
            toModels: function(data) {
                var metadata = (_.isString(data)) ? JSON.parse(data) : data,
                    models = [];

                for (var model in metadata) {
                    if (metadata.hasOwnProperty(model)) {
                        models.push(metadata[model]);
                    }
                }

                return models;
            },

            /**
        * @function
        *
        * Synchronize data from `Advanced` tab of Video player with data in
        * `Basic` tab. It is called when we go from `Advanced` to `Basic` tab.
        *
        * @param {object} metadataCollection Collection containing all models
        *                                    with information about metadata
        *                                    setting editors in `Advanced` tab.
        *
        */
            syncBasicTab: function(metadataCollection, metadataView) {
                var result = [],
                    getField = Utils.getField,
                    component_locator = this.$el.closest('[data-locator]').data('locator'),
                    values = {},
                    videoUrl, metadata, modifiedValues;

                // If metadataCollection is not passed, just exit.
                if (!metadataCollection || !metadataView) {
                    return false;
                }

                // Get field that should be synchronized with `Advanced` tab fields.
                videoUrl = getField(this.collection, 'video_url');

                modifiedValues = metadataView.getModifiedMetadataValues();

                // Get values from `Advanced` tab fields (`html5_sources`,
                // `youtube_id_1_0`) that should be synchronized.
                var html5Sources = getField(metadataCollection, 'html5_sources').getDisplayValue();

                values.youtube = getField(metadataCollection, 'youtube_id_1_0').getDisplayValue();

                values.html5Sources = _.filter(html5Sources, function(value) {
                    var link = Utils.parseLink(value),
                        mode = link && link.mode;

                    return mode === 'html5' && mode;
                });

                // The length of youtube video_id should be 11 characters.
                if (values.youtube.length === 11) {
                // Just video id is retrieved from `Advanced` tab field and
                // it should be transformed to appropriate format.
                // OEoXaMPEzfM => http://youtu.be/OEoXaMPEzfM
                    values.youtube = Utils.getYoutubeLink(values.youtube);
                } else {
                    values.youtube = '';
                }

                result.push(values.youtube);
                result = result.concat(values.html5Sources);

                videoUrl.setValue(result);

                // Synchronize other fields that has the same `field_name` property.
                Utils.syncCollections(metadataCollection, this.collection);
            },

            /**
        * @function
        *
        * Synchronize data from `Basic` tab of Video player with data in
        * `Advanced` tab. It is called when we go from `Basic` to `Advanced` tab.
        *
        * @param {object} metadataCollection Collection containing all models
        *                                    with information about metadata
        *                                    setting editors in `Advanced` tab.
        *
        */
            syncAdvancedTab: function(metadataCollection, metadataView) {
                var getField = Utils.getField,
                    html5Sources, youtube, videoUrlValue, result;

                // if metadataCollection is not passed, just exit.
                if (!metadataCollection) {
                    return false;
                }

                // Get fields from `Advenced` tab (`html5_sources`, `youtube_id_1_0`)
                // that should be synchronized.
                html5Sources = getField(metadataCollection, 'html5_sources');

                youtube = getField(metadataCollection, 'youtube_id_1_0');

                // Get value from `Basic` tab `VideoUrl` field that should be
                // synchronized.
                videoUrlValue = getField(this.collection, 'video_url')
                    .getDisplayValue();

                // Change list representation format to more convenient and group
                // them by mode (`youtube`, `html5`).
                //                  Before:
                // [
                //      'http://youtu.be/OEoXaMPEzfM',
                //      'video_name.mp4',
                //      'video_name.webm'
                // ]
                //                  After:
                // {
                //      youtube: [{mode: `youtube`, type: `youtube`, ...}],
                //      html5: [
                //          {mode: `html5`, type: `mp4`, ...},
                //          {mode: `html5`, type: `webm`, ...}
                //      ]
                // }
                result = _.groupBy(
                    videoUrlValue,
                    function(value) {
                        return Utils.parseLink(value).mode;
                    }
                );

                if (html5Sources) {
                    html5Sources.setValue(result.html5 || []);
                }

                if (youtube) {
                    if (result.youtube) {
                        result = Utils.parseLink(result.youtube[0]).video;
                    } else {
                        result = '';
                    }

                    youtube.setValue(result);
                }

                // Synchronize other fields that has the same `field_name` property.
                Utils.syncCollections(this.collection, metadataCollection);
            },

            handleUpdateEdxVideoId: function(edxVideoId) {
                var edxVideoIdField = Utils.getField(this.collection, 'edx_video_id');
                edxVideoIdField.setValue(edxVideoId);
            },

            getLocator: function() {
                return this.$el.closest('[data-locator]').data('locator');
            },

            /**
         * Event handler for `transcripts:basicTabFieldChanged` event.
         */
            handleFieldChanged: function() {
                var views = this.settingsView.views,
                    videoURLSView = views.video_url,
                    edxVideoIdView = views.edx_video_id,
                    edxVideoIdData = edxVideoIdView.getData(),
                    videoURLsData = videoURLSView.getVideoObjectsList(),
                    data = videoURLsData.concat(edxVideoIdData),
                    locator = this.getLocator();

                Utils.command('check', locator, data)
                    .done(function(response) {
                        videoURLSView.updateOnCheckTranscriptSuccess(videoURLsData, response);
                    })
                    .fail(function(response) {
                        videoURLSView.showServerError(response);
                    });
            },

            destroy: function() {
                this.stopListening();
                this.undelegateEvents();
                this.$el.empty();
            }
        });

        return Editor;
    });