/**
 * wp.media.controller.CollectionAdd
 *
 * A state for adding attachments to a collection (e.g. video playlist).
 *
 * @class
 * @augments wp.media.controller.Library
 * @augments wp.media.controller.State
 * @augments Backbone.Model
 *
 * @param {object}                     [attributes]                         The attributes hash passed to the state.
 * @param {string}                     [attributes.id=library]      Unique identifier.
 * @param {string}                     attributes.title                    Title for the state. Displays in the frame's title region.
 * @param {boolean}                    [attributes.multiple=add]            Whether multi-select is enabled. @todo 'add' doesn't seem do anything special, and gets used as a boolean.
 * @param {wp.media.model.Attachments} [attributes.library]                 The attachments collection to browse.
 *                                                                          If one is not supplied, a collection of attachments of the specified type will be created.
 * @param {boolean|string}             [attributes.filterable=uploaded]     Whether the library is filterable, and if so what filters should be shown.
 *                                                                          Accepts 'all', 'uploaded', or 'unattached'.
 * @param {string}                     [attributes.menu=gallery]            Initial mode for the menu region.
 * @param {string}                     [attributes.content=upload]          Initial mode for the content region.
 *                                                                          Overridden by persistent user setting if 'contentUserSetting' is true.
 * @param {string}                     [attributes.router=browse]           Initial mode for the router region.
 * @param {string}                     [attributes.toolbar=gallery-add]     Initial mode for the toolbar region.
 * @param {boolean}                    [attributes.searchable=true]         Whether the library is searchable.
 * @param {boolean}                    [attributes.sortable=true]           Whether the Attachments should be sortable. Depends on the orderby property being set to menuOrder on the attachments collection.
 * @param {boolean}                    [attributes.autoSelect=true]         Whether an uploaded attachment should be automatically added to the selection.
 * @param {boolean}                    [attributes.contentUserSetting=true] Whether the content region's mode should be set and persisted per user.
 * @param {int}                        [attributes.priority=100]            The priority for the state link in the media menu.
 * @param {boolean}                    [attributes.syncSelection=false]     Whether the Attachments selection should be persisted from the last state.
 *                                                                          Defaults to false because for this state, because the library of the Edit Gallery state is the selection.
 * @param {string}                     attributes.type                   The collection's media type. (e.g. 'video').
 * @param {string}                     attributes.collectionType         The collection type. (e.g. 'playlist').
 */
var Selection = wp.media.model.Selection,
	Library = wp.media.controller.Library,
	CollectionAdd;

CollectionAdd = Library.extend({
	defaults: _.defaults( {
		// Selection defaults. @see media.model.Selection
		multiple:      'add',
		// Attachments browser defaults. @see media.view.AttachmentsBrowser
		filterable:    'uploaded',

		priority:      100,
		syncSelection: false
	}, Library.prototype.defaults ),

	/**
	 * @since 3.9.0
	 */
	initialize: function() {
		var collectionType = this.get('collectionType');

		if ( 'video' === this.get( 'type' ) ) {
			collectionType = 'video-' + collectionType;
		}

		this.set( 'id', collectionType + '-library' );
		this.set( 'toolbar', collectionType + '-add' );
		this.set( 'menu', collectionType );

		// If we haven't been provided a `library`, create a `Selection`.
		if ( ! this.get('library') ) {
			this.set( 'library', wp.media.query({ type: this.get('type') }) );
		}
		Library.prototype.initialize.apply( this, arguments );
	},

	/**
	 * @since 3.9.0
	 */
	activate: function() {
		var library = this.get('library'),
			editLibrary = this.get('editLibrary'),
			edit = this.frame.state( this.get('collectionType') + '-edit' ).get('library');

		if ( editLibrary && editLibrary !== edit ) {
			library.unobserve( editLibrary );
		}

		// Accepts attachments that exist in the original library and
		// that do not exist in gallery's library.
		library.validator = function( attachment ) {
			return !! this.mirroring.get( attachment.cid ) && ! edit.get( attachment.cid ) && Selection.prototype.validator.apply( this, arguments );
		};

		// Reset the library to ensure that all attachments are re-added
		// to the collection. Do so silently, as calling `observe` will
		// trigger the `reset` event.
		library.reset( library.mirroring.models, { silent: true });
		library.observe( edit );
		this.set('editLibrary', edit);

		Library.prototype.activate.apply( this, arguments );
	}
});

module.exports = CollectionAdd;
