/*globals wp, _, Backbone */

/**
 * wp.media.controller.Library
 *
 * A state for choosing an attachment or group of attachments from the media library.
 *
 * @class
 * @augments wp.media.controller.State
 * @augments Backbone.Model
 * @mixes media.selectionSync
 *
 * @param {object}                          [attributes]                         The attributes hash passed to the state.
 * @param {string}                          [attributes.id=library]              Unique identifier.
 * @param {string}                          [attributes.title=Media library]     Title for the state. Displays in the media menu and the frame's title region.
 * @param {wp.media.model.Attachments}      [attributes.library]                 The attachments collection to browse.
 *                                                                               If one is not supplied, a collection of all attachments will be created.
 * @param {wp.media.model.Selection|object} [attributes.selection]               A collection to contain attachment selections within the state.
 *                                                                               If the 'selection' attribute is a plain JS object,
 *                                                                               a Selection will be created using its values as the selection instance's `props` model.
 *                                                                               Otherwise, it will copy the library's `props` model.
 * @param {boolean}                         [attributes.multiple=false]          Whether multi-select is enabled.
 * @param {string}                          [attributes.content=upload]          Initial mode for the content region.
 *                                                                               Overridden by persistent user setting if 'contentUserSetting' is true.
 * @param {string}                          [attributes.menu=default]            Initial mode for the menu region.
 * @param {string}                          [attributes.router=browse]           Initial mode for the router region.
 * @param {string}                          [attributes.toolbar=select]          Initial mode for the toolbar region.
 * @param {boolean}                         [attributes.searchable=true]         Whether the library is searchable.
 * @param {boolean|string}                  [attributes.filterable=false]        Whether the library is filterable, and if so what filters should be shown.
 *                                                                               Accepts 'all', 'uploaded', or 'unattached'.
 * @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.describe=false]          Whether to offer UI to describe attachments - e.g. captioning images in a gallery.
 * @param {boolean}                         [attributes.contentUserSetting=true] Whether the content region's mode should be set and persisted per user.
 * @param {boolean}                         [attributes.syncSelection=true]      Whether the Attachments selection should be persisted from the last state.
 */
var selectionSync = require( '../utils/selection-sync.js' ),
	State = require( './state.js' ),
	l10n = wp.media.view.l10n,
	getUserSetting = window.getUserSetting,
	setUserSetting = window.setUserSetting,
	Library;

Library = State.extend({
	defaults: {
		id:                 'library',
		title:              l10n.mediaLibraryTitle,
		multiple:           false,
		content:            'upload',
		menu:               'default',
		router:             'browse',
		toolbar:            'select',
		searchable:         true,
		filterable:         false,
		sortable:           true,
		autoSelect:         true,
		describe:           false,
		contentUserSetting: true,
		syncSelection:      true
	},

	/**
	 * If a library isn't provided, query all media items.
	 * If a selection instance isn't provided, create one.
	 *
	 * @since 3.5.0
	 */
	initialize: function() {
		var selection = this.get('selection'),
			props;

		if ( ! this.get('library') ) {
			this.set( 'library', wp.media.query() );
		}

		if ( ! ( selection instanceof wp.media.model.Selection ) ) {
			props = selection;

			if ( ! props ) {
				props = this.get('library').props.toJSON();
				props = _.omit( props, 'orderby', 'query' );
			}

			this.set( 'selection', new wp.media.model.Selection( null, {
				multiple: this.get('multiple'),
				props: props
			}) );
		}

		this.resetDisplays();
	},

	/**
	 * @since 3.5.0
	 */
	activate: function() {
		this.syncSelection();

		wp.Uploader.queue.on( 'add', this.uploading, this );

		this.get('selection').on( 'add remove reset', this.refreshContent, this );

		if ( this.get( 'router' ) && this.get('contentUserSetting') ) {
			this.frame.on( 'content:activate', this.saveContentMode, this );
			this.set( 'content', getUserSetting( 'libraryContent', this.get('content') ) );
		}
	},

	/**
	 * @since 3.5.0
	 */
	deactivate: function() {
		this.recordSelection();

		this.frame.off( 'content:activate', this.saveContentMode, this );

		// Unbind all event handlers that use this state as the context
		// from the selection.
		this.get('selection').off( null, null, this );

		wp.Uploader.queue.off( null, null, this );
	},

	/**
	 * Reset the library to its initial state.
	 *
	 * @since 3.5.0
	 */
	reset: function() {
		this.get('selection').reset();
		this.resetDisplays();
		this.refreshContent();
	},

	/**
	 * Reset the attachment display settings defaults to the site options.
	 *
	 * If site options don't define them, fall back to a persistent user setting.
	 *
	 * @since 3.5.0
	 */
	resetDisplays: function() {
		var defaultProps = wp.media.view.settings.defaultProps;
		this._displays = [];
		this._defaultDisplaySettings = {
			align: defaultProps.align || getUserSetting( 'align', 'none' ),
			size:  defaultProps.size  || getUserSetting( 'imgsize', 'medium' ),
			link:  defaultProps.link  || getUserSetting( 'urlbutton', 'file' )
		};
	},

	/**
	 * Create a model to represent display settings (alignment, etc.) for an attachment.
	 *
	 * @since 3.5.0
	 *
	 * @param {wp.media.model.Attachment} attachment
	 * @returns {Backbone.Model}
	 */
	display: function( attachment ) {
		var displays = this._displays;

		if ( ! displays[ attachment.cid ] ) {
			displays[ attachment.cid ] = new Backbone.Model( this.defaultDisplaySettings( attachment ) );
		}
		return displays[ attachment.cid ];
	},

	/**
	 * Given an attachment, create attachment display settings properties.
	 *
	 * @since 3.6.0
	 *
	 * @param {wp.media.model.Attachment} attachment
	 * @returns {Object}
	 */
	defaultDisplaySettings: function( attachment ) {
		var settings = this._defaultDisplaySettings;
		if ( settings.canEmbed = this.canEmbed( attachment ) ) {
			settings.link = 'embed';
		}
		return settings;
	},

	/**
	 * Whether an attachment can be embedded (audio or video).
	 *
	 * @since 3.6.0
	 *
	 * @param {wp.media.model.Attachment} attachment
	 * @returns {Boolean}
	 */
	canEmbed: function( attachment ) {
		// If uploading, we know the filename but not the mime type.
		if ( ! attachment.get('uploading') ) {
			var type = attachment.get('type');
			if ( type !== 'audio' && type !== 'video' ) {
				return false;
			}
		}

		return _.contains( wp.media.view.settings.embedExts, attachment.get('filename').split('.').pop() );
	},


	/**
	 * If the state is active, no items are selected, and the current
	 * content mode is not an option in the state's router (provided
	 * the state has a router), reset the content mode to the default.
	 *
	 * @since 3.5.0
	 */
	refreshContent: function() {
		var selection = this.get('selection'),
			frame = this.frame,
			router = frame.router.get(),
			mode = frame.content.mode();

		if ( this.active && ! selection.length && router && ! router.get( mode ) ) {
			this.frame.content.render( this.get('content') );
		}
	},

	/**
	 * Callback handler when an attachment is uploaded.
	 *
	 * Switch to the Media Library if uploaded from the 'Upload Files' tab.
	 *
	 * Adds any uploading attachments to the selection.
	 *
	 * If the state only supports one attachment to be selected and multiple
	 * attachments are uploaded, the last attachment in the upload queue will
	 * be selected.
	 *
	 * @since 3.5.0
	 *
	 * @param {wp.media.model.Attachment} attachment
	 */
	uploading: function( attachment ) {
		var content = this.frame.content;

		if ( 'upload' === content.mode() ) {
			this.frame.content.mode('browse');
		}

		if ( this.get( 'autoSelect' ) ) {
			this.get('selection').add( attachment );
			this.frame.trigger( 'library:selection:add' );
		}
	},

	/**
	 * Persist the mode of the content region as a user setting.
	 *
	 * @since 3.5.0
	 */
	saveContentMode: function() {
		if ( 'browse' !== this.get('router') ) {
			return;
		}

		var mode = this.frame.content.mode(),
			view = this.frame.router.get();

		if ( view && view.get( mode ) ) {
			setUserSetting( 'libraryContent', mode );
		}
	}
});

// Make selectionSync available on any Media Library state.
_.extend( Library.prototype, selectionSync );

module.exports = Library;
