/**
 * Sorted list widget. This is a group widget that sorts its items
 * according to a given sorting callback.
 *
 * @class
 * @extends OO.ui.Widget
 * @mixes OO.SortedEmitterList
 *
 * @constructor
 * @param {Function} sortingCallback Callback that compares two items.
 * @param {Object} [config={}]
 * @param {jQuery} [config.$group] The container element created by the class. If this configuration
 *  is omitted, the group element will use a generated `<div>`.
 * @param {jQuery} [config.$overlay] A jQuery element functioning as an overlay
 *  for popups.
 * @param {number} [config.timestamp=0] A fallback timestamp for the list, usually representing
 *  the timestamp of the latest item.
 * @param {boolean} [config.animated=false] Animate the sorting of items
 */
mw.echo.ui.SortedListWidget = function MwEchoUiSortedListWidget( sortingCallback, config ) {
	config = config || {};

	// Parent constructor
	mw.echo.ui.SortedListWidget.super.call( this, config );
	// Mixin constructor
	OO.SortedEmitterList.call( this, sortingCallback );

	// Properties
	this.$group = null;
	this.$overlay = config.$overlay;
	this.timestamp = config.timestamp || 0;

	this.animated = !!config.animated;

	// Initialization
	this.setGroupElement( config.$group || $( '<div>' ) );

	this.$group.addClass( 'mw-echo-ui-sortedListWidget-group' );
	this.$element
		.addClass( 'mw-echo-ui-sortedListWidget' )
		.append( this.$group );
};

/* Initialization */

OO.inheritClass( mw.echo.ui.SortedListWidget, OO.ui.Widget );
OO.mixinClass( mw.echo.ui.SortedListWidget, OO.SortedEmitterList );

/* Methods */

/**
 * @inheritdoc
 */
mw.echo.ui.SortedListWidget.prototype.onItemSortChange = function ( item ) {
	if ( this.animated ) {
		// Create a fake widget with cloned contents
		const fakeWidget = new mw.echo.ui.ClonedNotificationItemWidget(
			item.$element.clone( true ),
			{
				id: item.getId() + '.42',
				// HACK: We are assuming that the item sort change
				// is triggered when the item is marked read/unread
				// This is a generally correct assumption, but it may
				// cause issues when the case is unclear. We should try
				// and come up with a good way to measure the previous
				// state of the item instead
				read: !item.isRead(),
				foreign: item.isForeign(),
				timestamp: item.getTimestamp(),
			},
		);

		// remove real item from item list, without touching the DOM
		this.removeItems( [ item ] );

		// insert real item, hidden
		item.$element.hide();
		this.addItems( [ item, fakeWidget ] );

		// fade out fake
		// FIXME: Use CSS transition
		// eslint-disable-next-line no-jquery/no-fade
		fakeWidget.$element.fadeOut( 400, () => {
			// remove fake
			this.removeItems( [ fakeWidget ] );
			// fade-in real item
			// eslint-disable-next-line no-jquery/no-fade
			item.$element.fadeIn( 400 );
		} );
	} else {
		// Mixin method
		OO.SortedEmitterList.prototype.onItemSortChange.call( this, item );
	}
};
/**
 * Set the group element.
 *
 * If an element is already set, items will be moved to the new element.
 *
 * @param {jQuery} $group Element to use as group
 */
mw.echo.ui.SortedListWidget.prototype.setGroupElement = function ( $group ) {
	this.$group = $group;
	for ( let i = 0, len = this.items.length; i < len; i++ ) {
		this.$group.append( this.items[ i ].$element );
	}
};

/**
 * Get an item by its id.
 *
 * @param {number} id Item id to search for
 * @return {OO.ui.Element|null} Item with equivalent data, `null` if none exists
 */
mw.echo.ui.SortedListWidget.prototype.getItemFromId = function ( id ) {
	const hash = OO.getHash( id );

	for ( let i = 0, len = this.items.length; i < len; i++ ) {
		const item = this.items[ i ];
		if ( hash === OO.getHash( item.getId() ) ) {
			return item;
		}
	}

	return null;
};

/**
 * Get an item by its data.
 *
 * @param {string} data Item data to search for
 * @return {OO.ui.Element|null} Item with equivalent data, `null` if none exists
 */
mw.echo.ui.SortedListWidget.prototype.findItemFromData = function ( data ) {
	const hash = OO.getHash( data );

	for ( let i = 0, len = this.items.length; i < len; i++ ) {
		const item = this.items[ i ];
		if ( hash === OO.getHash( item.getData() ) ) {
			return item;
		}
	}

	return null;
};

/**
 * Remove items.
 *
 * @param {OO.EventEmitter[]} items Items to remove
 * @chainable
 * @return {mw.echo.ui.SortedListWidget}
 * @fires OO.EmitterList#remove
 */
mw.echo.ui.SortedListWidget.prototype.removeItems = function ( items ) {
	if ( !Array.isArray( items ) ) {
		items = [ items ];
	}

	if ( items.length > 0 ) {
		// Remove specific items
		for ( let i = 0; i < items.length; i++ ) {
			const item = items[ i ];
			const index = this.items.indexOf( item );
			if ( index !== -1 ) {
				item.setElementGroup( null );
				item.$element.detach();
			}
		}
	}

	return OO.SortedEmitterList.prototype.removeItems.call( this, items );
};

/**
 * Utility method to insert an item into the list, and
 * connect it to aggregate events.
 *
 * Don't call this directly unless you know what you're doing.
 * Use #addItems instead.
 *
 * @private
 * @param {OO.EventEmitter} item Items to add
 * @param {number} index Index to add items at
 * @return {number} The index the item was added at
 */
mw.echo.ui.SortedListWidget.prototype.insertItem = function ( item, index ) {
	// Call parent and get the normalized index
	index = OO.SortedEmitterList.prototype.insertItem.call( this, item, index );

	item.setElementGroup( this );

	this.attachItemToDom( item, index );

	return index;
};

/**
 * Move an item from its current position to a new index.
 *
 * The item is expected to exist in the list. If it doesn't,
 * the method will throw an exception.
 *
 * @private
 * @param {OO.EventEmitter} item Items to add
 * @param {number} index Index to move the item to
 * @return {number} The index the item was moved to
 * @throws {Error} If item is not in the list
 */
mw.echo.ui.SortedListWidget.prototype.moveItem = function ( item, index ) {
	// Call parent and get the normalized index
	index = OO.SortedEmitterList.prototype.moveItem.call( this, item, index );

	this.attachItemToDom( item, index );

	return index;
};

/**
 * Attach the item to the Dom in its intended position, based
 * on the given index.
 *
 * @param {OO.EventEmitter} item Item
 * @param {number} index Index to insert the item into
 */
mw.echo.ui.SortedListWidget.prototype.attachItemToDom = function ( item, index ) {
	if ( index === undefined || index < 0 || index >= this.items.length - 1 ) {
		this.$group.append( item.$element.get( 0 ) );
	} else if ( index === 0 ) {
		this.$group.prepend( item.$element.get( 0 ) );
	} else {
		this.items[ index + 1 ].$element.before( item.$element.get( 0 ) );
	}
};

/**
 * Clear all items
 *
 * @chainable
 * @return {mw.echo.ui.SortedListWidget}
 * @fires OO.EmitterList#clear
 */
mw.echo.ui.SortedListWidget.prototype.clearItems = function () {
	for ( let i = 0, len = this.items.length; i < len; i++ ) {
		const item = this.items[ i ];
		item.setElementGroup( null );
		item.$element.detach();
	}

	// Mixin method
	return OO.SortedEmitterList.prototype.clearItems.call( this );
};

/**
 * Get the timestamp of the list by taking the latest notification
 * timestamp.
 *
 * @return {string} Latest timestamp
 */
mw.echo.ui.SortedListWidget.prototype.getTimestamp = function () {
	const items = this.getItems();

	return (
		items.length > 0 ?
			items[ 0 ].getTimestamp() :
			this.timestamp
	);
};
