/**
 * Cross-wiki notification item widget.
 * This widget is expandable and displays groups of
 * notification item lists by their sources.
 *
 * TODO: When we have local bundles (without groups of lists)
 * we can separate the "expand" functionality and UI to another mixin
 * so we can use it with both widgets.
 *
 * @class
 * @extends mw.echo.ui.NotificationItemWidget
 * @mixes OO.ui.mixin.PendingElement
 *
 * @constructor
 * @param {mw.echo.Controller} controller Echo notifications controller
 * @param {mw.echo.dm.CrossWikiNotificationItem} model Notification group model
 * @param {Object} [config={}]
 * @param {boolean} [config.animateSorting=false] Animate the sorting of items
 */
mw.echo.ui.CrossWikiNotificationItemWidget = function MwEchoUiCrossWikiNotificationItemWidget( controller, model, config ) {
	config = config || {};

	// Parent constructor
	mw.echo.ui.CrossWikiNotificationItemWidget.super.call( this, controller, model, config );
	// Mixin constructors
	OO.ui.mixin.PendingElement.call( this, config );

	// In cross-wiki groups we only have 'mark as read'
	this.toggleMarkAsReadButtons( true );

	this.listWidget = new mw.echo.ui.SortedListWidget(
		// Sorting callback
		( ( a, b ) => {
			// Define the sorting order.
			// This will go by the lists' timestamp, which in turn
			// take the latest timestamp in their items
			if ( b.getTimestamp() < a.getTimestamp() ) {
				return -1;
			} else if ( b.getTimestamp() > a.getTimestamp() ) {
				return 1;
			}

			// Fallback on IDs
			return b.getSource() - a.getSource();
		} ),
		// Config
		{
			classes: [ 'mw-echo-ui-crossWikiNotificationItemWidget-group' ],
			timestamp: this.getTimestamp(),
			$overlay: this.$overlay,
			animated: config.animateSorting
		}
	);

	this.listWidget.$element
		// We have to manually set the display to 'none' here because
		// otherwise the 'slideUp' and 'slideDown' jQuery effects don't
		// work
		.css( 'display', 'none' );
	this.setPendingElement( this.listWidget.$element );

	this.errorWidget = new mw.echo.ui.PlaceholderItemWidget();
	this.errorWidget.toggle( false );

	// Initialize closed
	this.showTitles = true;
	this.expanded = false;
	this.fetchedOnce = false;

	// Add "expand" button
	this.toggleExpandButton = new OO.ui.ButtonOptionWidget( {
		icon: 'expand',
		framed: false,
		classes: [ 'mw-echo-ui-notificationItemWidget-content-actions-button' ]
	} );
	this.updateExpandButton();
	this.actionsButtonSelectWidget.addItems( [ this.toggleExpandButton ] );

	// Events
	this.model.connect( this, { discard: 'onModelDiscard' } );
	this.toggleExpandButton.connect( this, { click: 'expand' } );
	this.$content.on( 'click', this.expand.bind( this ) );

	// TODO: Handle cases where the group became empty or a case where the group only has 1 item left.
	// Note: Right now this code works primarily for cross-wiki notifications. These act differently
	// than local bundles. Cross-wiki notifications, when they "lose" their items for being read, they
	// vanish from the list. Unlike them, the plan for local bundles is that read sub-items go outside
	// the bundle and become their own items in the general notificationsWidget, and when the local bundle
	// has 1 notification left, the group will actually transform into that last notification item.
	// We don't listen to the empty event right now, because the entire item is deleted in cross-wiki
	// notifications. When we work on local bundles, we will have to add that event listener per item.

	// Initialization
	this.populateFromModel();
	this.toggleExpanded( false );
	this.toggleRead( false );
	this.toggleTitles( true );
	this.$element
		.addClass( 'mw-echo-ui-crossWikiNotificationItemWidget' )
		.append(
			$( '<div>' )
				.addClass( 'mw-echo-ui-crossWikiNotificationItemWidget-separator' ),
			this.listWidget.$element,
			this.errorWidget.$element
		);
};

/* Initialization */

OO.inheritClass( mw.echo.ui.CrossWikiNotificationItemWidget, mw.echo.ui.NotificationItemWidget );
OO.mixinClass( mw.echo.ui.CrossWikiNotificationItemWidget, OO.ui.mixin.PendingElement );

/* Methods */

/**
 * Respond to model removing source group
 *
 * @param {string} groupName Symbolic name of the group
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.onModelDiscard = function ( groupName ) {
	const list = this.getList(),
		group = list.getItemFromId( groupName );

	list.removeItems( [ group ] );

	if ( list.isEmpty() ) {
		this.controller.removeCrossWikiItem();
	}
};

/**
 * @inheritdoc
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.markRead = function () {
	// Cross wiki notification is always only marked as read, never as
	// unread. The original parameter is unneeded
	this.controller.markEntireCrossWikiItemAsRead();
};

/**
 * Populate the items in this widget according to the data
 * in the model
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.populateFromModel = function () {
	const groupWidgets = [],
		groups = this.model.getList().getItems();

	for ( let i = 0; i < groups.length; i++ ) {
		// Create SubGroup widgets
		groupWidgets.push(
			new mw.echo.ui.SubGroupListWidget(
				this.controller,
				groups[ i ],
				{
					$overlay: this.$overlay,
					showTitle: this.showTitles
				}
			)
		);
	}
	this.getList().addItems( groupWidgets );
};

/**
 * Toggle the visibility of the titles
 *
 * @param {boolean} [show] Show titles
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.toggleTitles = function ( show ) {
	const items = this.getList().getItems();

	show = show === undefined ? !this.showTitles : show;

	if ( this.showTitles !== show ) {
		this.showTitles = show;
		for ( let i = 0; i < items.length; i++ ) {
			items[ i ].toggleTitle( show );
		}
	}
};

/**
 * Check whether the titles should be shown and toggle them
 * in each of the group lists.
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.checkShowTitles = function () {
	this.toggleTitles( this.getList().getItemCount() > 1 );
};

/**
 * Toggle the visibility of the notification item list and the placeholder/error widget.
 *
 * @param {boolean} showList Show the list
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.toggleListDisplay = function ( showList ) {
	this.errorWidget.toggle( !showList );
	this.listWidget.toggle( showList );
};

/**
 * Show an error message
 *
 * @param {string} [label=''] Error label
 * @param {string} [link=''] Error link
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.showErrorMessage = function ( label, link ) {
	this.errorWidget.setLabel( label || '' );
	this.errorWidget.setLink( link || '' );

	this.toggleListDisplay( false );
};

/**
 * Expand the group and fetch the list of notifications.
 * Only fetch the first time we expand.
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.expand = function () {
	this.toggleExpanded( !this.expanded );
	this.updateExpandButton();

	if ( !this.expanded ) {
		return;
	}

	if ( !this.fetchedOnce ) {
		// Expand
		this.pushPending();
		this.toggleListDisplay( true );
		// Query all sources
		this.controller.fetchCrossWikiNotifications()
			.catch(
				( result ) => {
					const loginPageTitle = mw.Title.newFromText( 'Special:UserLogin' );
					// If failure, check if the failure is due to login
					// so we can display a more comprehensive error
					// message in that case
					if ( result.errCode === 'notlogin-required' ) {
						// Login error
						this.showErrorMessage(
							mw.msg( 'echo-notification-popup-loginrequired' ),
							// Set the option link to the login page
							loginPageTitle.getUrl()
						);
					} else {
						// General error
						this.showErrorMessage( mw.msg( 'echo-api-failure' ) );
					}
				}
			)
			.always( this.popPending.bind( this ) );

		// Only run the fetch notifications action once
		this.fetchedOnce = true;
	}
};

/**
 * Toggle the expand/collapsed state of this group widget
 *
 * @param {boolean} show Show the widget expanded
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.toggleExpanded = function ( show ) {
	this.expanded = show !== undefined ? !!show : !this.expanded;

	this.$element.toggleClass( 'mw-echo-ui-crossWikiNotificationItemWidget-expanded', this.expanded );

	if ( this.expanded ) {
		// FIXME: Use CSS transition
		// eslint-disable-next-line no-jquery/no-slide
		this.getList().$element.slideDown();
	} else {
		// eslint-disable-next-line no-jquery/no-slide
		this.getList().$element.slideUp();
	}
};

/**
 * Update the expand button label
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.updateExpandButton = function () {
	const type = this.model.getType();

	this.toggleExpandButton.setLabel(
		this.expanded ?
			mw.msg( 'notification-link-text-collapse-all' ) :
			// Messages that appear here are:
			// * notification-link-text-expand-alert-count
			// * notification-link-text-expand-notice-count
			mw.msg(
				'notification-link-text-expand-' +
					( type === 'message' ? 'notice' : type ) +
					'-count',
				mw.language.convertNumber( this.model.getCount() )
			)
	);
	this.toggleExpandButton.setIcon(
		this.expanded ?
			'collapse' :
			'expand'
	);
};

/**
 * Get the list widget contained in this item
 *
 * @return {mw.echo.ui.SortedListWidget} List widget
 */
mw.echo.ui.CrossWikiNotificationItemWidget.prototype.getList = function () {
	return this.listWidget;
};
