/*
 * This file is part of the MediaWiki extension MultimediaViewer.
 *
 * MultimediaViewer is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * MultimediaViewer is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with MultimediaViewer.  If not, see <http://www.gnu.org/licenses/>.
 */

const Description = require( './mmv.ui.description.js' );
const UiElement = require( './mmv.ui.js' );
const MetadataPanelScroller = require( './mmv.ui.metadataPanelScroller.js' );
const Permission = require( './mmv.ui.permission.js' );
const ProgressBar = require( './mmv.ui.progressBar.js' );
const StripeButtons = require( './mmv.ui.stripeButtons.js' );
const TruncatableTextField = require( './mmv.ui.truncatableTextField.js' );

/**
 * Represents the metadata panel in the viewer
 */
class MetadataPanel extends UiElement {
	/**
	 * @param {jQuery} $container The container for the panel (.mw-mmv-post-image).
	 * @param {jQuery} $aboveFold The brighter headline of the metadata panel (.mw-mmv-above-fold).
	 *  Called "aboveFold" for historical reasons, but actually a part of the next sibling of the element
	 *  is also above the fold (bottom of the screen).
	 */
	constructor( $container, $aboveFold ) {
		super( $container );

		this.$aboveFold = $aboveFold;

		this.initializeHeader();
		this.initializeImageMetadata();
	}

	/**
	 * FIXME this should be in the jquery.fullscreen plugin.
	 *
	 * @return {boolean}
	 */
	isFullscreened() {
		return $( this.$container ).closest( '.jq-fullscreened' ).length > 0;
	}

	attach() {
		this.scroller.attach();
		this.buttons.attach();
		this.title.attach();
		this.creditField.attach();

		this.$title
			.add( this.$authorAndSource )
			.add( this.title.$ellipsis )
			.add( this.creditField.$ellipsis )
			.on( 'click.mmv-mp', ( e ) => {
				const clickTargetIsLink = $( e.target ).is( 'a' );
				const clickTargetIsTruncated = !!$( e.target ).closest( '.mw-mmv-ttf-truncated' ).length;
				const someTextIsExpanded = !!$( e.target ).closest( '.mw-mmv-untruncated' ).length;

				if ( !clickTargetIsLink && // don't interfere with clicks on links in the text
					clickTargetIsTruncated && // don't expand when non-truncated text is clicked
					!someTextIsExpanded // ignore clicks if text is already expanded
				) {
					if ( this.isFullscreened() ) {
						this.revealTruncatedText();
					} else {
						this.scroller.toggle( 'up' );
					}
				}
			} );

		$( this.$container ).on( 'mmv-metadata-open.mmv-mp mmv-metadata-reveal-truncated-text.mmv-mp', () => {
			this.revealTruncatedText();
		} ).on( 'mmv-metadata-close.mmv-mp', () => {
			this.hideTruncatedText();
		} ).on( 'mouseleave.mmv-mp', () => {
			if ( this.isFullscreened() ) {
				const duration = parseFloat( this.$container.css( 'transition-duration' ) ) * 1000 || 0;
				this.panelShrinkTimeout = setTimeout( () => {
					this.hideTruncatedText();
				}, duration );
			}
		} ).on( 'mouseenter.mmv-mp', () => {
			clearTimeout( this.panelShrinkTimeout );
		} ).on( 'mmv-permission-grow.mmv-mp', () => {
			this.$permissionLink
				.text( mw.msg( 'multimediaviewer-permission-link-hide' ) );
		} ).on( 'mmv-permission-shrink.mmv-mp', () => {
			this.$permissionLink
				.text( mw.msg( 'multimediaviewer-permission-link' ) );
		} );

		this.handleEvent( 'fullscreenchange.lip', () => {
			this.hideTruncatedText();
		} );
	}

	unattach() {
		this.scroller.freezeHeight();

		this.$title
			.add( this.title.$ellipsis )
			.add( this.$authorAndSource )
			.add( this.creditField.$ellipsis )
			.off( 'click.mmv-mp' );

		$( this.$container ).off( '.mmv-mp' );

		this.scroller.unattach();
		this.buttons.unattach();
		this.clearEvents();
	}

	empty() {
		this.scroller.freezeHeight();
		this.scroller.empty();

		this.buttons.empty();

		this.description.empty();
		this.permission.empty();

		this.$title.removeClass( 'error' );
		this.title.empty();
		this.creditField.empty();

		this.$license.empty().prop( 'href', '#' );
		this.$licenseLi.addClass( 'empty' );
		this.$permissionLink.hide();
		this.$restrictions.children().hide();

		this.$filename.empty();
		this.$filenamePrefix.empty();
		this.$filenameLi.addClass( 'empty' );

		this.$datetimeCreated.empty();
		this.$datetimeCreatedLi.addClass( 'empty' );
		this.$datetimeUpdated.empty();
		this.$datetimeUpdatedLi.addClass( 'empty' );

		this.$location.empty();
		this.$locationLi.addClass( 'empty' );

		this.progressBar.empty();

		this.$container.removeClass( 'mw-mmv-untruncated' );
	}

	/* Initialization methods */
	/**
	 * Initializes the header, which contains the title, credit, and license elements.
	 */
	initializeHeader() {
		this.progressBar = new ProgressBar( this.$aboveFold );

		this.scroller = new MetadataPanelScroller( this.$container, this.$aboveFold );

		this.$titleDiv = $( '<div>' )
			.addClass( 'mw-mmv-title-contain' )
			.appendTo( this.$aboveFold );

		this.$container.append( this.$aboveFold );

		this.initializeButtons(); // float, needs to be on top
		this.initializeTitle();
	}

	/**
	 * Initializes the title elements.
	 */
	initializeTitle() {
		this.$titlePara = $( '<p>' )
			.addClass( 'mw-mmv-title-para mw-parser-output' )
			.appendTo( this.$aboveFold );

		this.$title = $( '<span>' )
			.addClass( 'mw-mmv-title' );

		this.title = new TruncatableTextField( this.$titlePara, this.$title, {
			styles: [ 'mw-mmv-title-small', 'mw-mmv-title-smaller' ]
		} );
		this.title.setTitle(
			mw.message( 'multimediaviewer-title-popup-text' ),
			mw.message( 'multimediaviewer-title-popup-text-more' )
		);

		this.$title.add( this.title.$ellipsis );
	}

	initializeButtons() {
		this.buttons = new StripeButtons( this.$titleDiv );
	}

	/**
	 * Initializes the main body of metadata elements.
	 */
	initializeImageMetadata() {
		this.$container.addClass( 'mw-mmv-ttf-ellipsis-container' );

		this.$imageMetadata = $( '<div>' )
			.addClass( 'mw-mmv-image-metadata' )
			.appendTo( this.$container );

		this.$imageMetadataLeft = $( '<div>' )
			.addClass( 'mw-mmv-image-metadata-column mw-mmv-image-metadata-desc-column' )
			.appendTo( this.$imageMetadata );

		this.$imageMetadataRight = $( '<div>' )
			.addClass( 'mw-mmv-image-metadata-column mw-mmv-image-metadata-links-column' )
			.appendTo( this.$imageMetadata );

		this.initializeCredit();
		this.description = new Description( this.$imageMetadataLeft );
		this.permission = new Permission( this.$imageMetadataLeft, this.scroller );
		this.initializeImageLinks();
	}

	/**
	 * Initializes the credit elements.
	 */
	initializeCredit() {
		this.$credit = $( '<p>' )
			.addClass( 'mw-mmv-credit empty' )
			.appendTo( this.$imageMetadataLeft );

		// we need an inline container for tipsy, otherwise it would be centered weirdly
		this.$authorAndSource = $( '<span>' )
			.addClass( 'mw-mmv-source-author' );

		this.creditField = new TruncatableTextField(
			this.$credit,
			this.$authorAndSource,
			{ styles: [] }
		);

		this.creditField.setTitle(
			mw.message( 'multimediaviewer-credit-popup-text' ),
			mw.message( 'multimediaviewer-credit-popup-text-more' )
		);

		this.$authorAndSource.add( this.creditField.$ellipsis );
	}

	/**
	 * Initializes the list of image metadata on the right side of the panel.
	 */
	initializeImageLinks() {
		this.$imageLinkDiv = $( '<div>' )
			.addClass( 'mw-mmv-image-links-div' )
			.appendTo( this.$imageMetadataRight );

		this.$imageLinks = $( '<ul>' )
			.addClass( 'mw-mmv-image-links' )
			.appendTo( this.$imageLinkDiv );

		this.initializeLicense();
		this.initializeFilename();
		this.initializeDatetime();
		this.initializeLocation();
	}

	/**
	 * Initializes the license elements.
	 */
	initializeLicense() {
		this.$licenseLi = $( '<li>' )
			.addClass( 'mw-mmv-license-li empty' )
			.appendTo( this.$imageLinks );

		this.$license = $( '<a>' )
			.addClass( 'mw-mmv-license' )
			.prop( 'href', '#' )
			.appendTo( this.$licenseLi );

		this.$restrictions = $( '<span>' )
			.addClass( 'mw-mmv-restrictions' )
			.appendTo( this.$licenseLi );

		this.$permissionLink = $( '<span>' )
			.addClass( 'mw-mmv-permission-link mw-mmv-label' )
			.text( mw.msg( 'multimediaviewer-permission-link' ) )
			.appendTo( this.$licenseLi )
			.hide()
			.on( 'click', () => {
				if ( this.permission.isFullSize() ) {
					this.permission.shrink();
				} else {
					this.permission.grow();
					this.scroller.toggle( 'up' );
				}
				return false;
			} );
	}

	/**
	 * Initializes the filename element.
	 */
	initializeFilename() {
		this.$filenameLi = $( '<li>' )
			.addClass( 'mw-mmv-filename-li empty' )
			.appendTo( this.$imageLinks );

		this.$filenamePrefix = $( '<span>' )
			.addClass( 'mw-mmv-filename-prefix' )
			.appendTo( this.$filenameLi );

		this.$filename = $( '<span>' )
			.addClass( 'mw-mmv-filename' )
			.appendTo( this.$filenameLi );
	}

	/**
	 * Initializes the upload date/time element.
	 */
	initializeDatetime() {
		this.$datetimeCreatedLi = $( '<li>' )
			.addClass( 'mw-mmv-datetime-li empty' )
			.appendTo( this.$imageLinks );

		this.$datetimeCreated = $( '<span>' )
			.addClass( 'mw-mmv-datetime' )
			.appendTo( this.$datetimeCreatedLi );

		this.$datetimeUpdatedLi = $( '<li>' )
			.addClass( 'mw-mmv-datetime-li empty' )
			.appendTo( this.$imageLinks );

		this.$datetimeUpdated = $( '<span>' )
			.addClass( 'mw-mmv-datetime' )
			.appendTo( this.$datetimeUpdatedLi );
	}

	/**
	 * Initializes the geolocation element.
	 */
	initializeLocation() {
		this.$locationLi = $( '<li>' )
			.addClass( 'mw-mmv-location-li empty' )
			.appendTo( this.$imageLinks );

		this.$location = $( '<a>' )
			.addClass( 'mw-mmv-location' )
			.appendTo( this.$locationLi );
	}

	/* Setters */
	/**
	 * Sets the image title at the top of the metadata panel.
	 * The title will be the first one available form the options below:
	 * - the image caption
	 * - the description from the filepage
	 * - the filename (without extension)
	 *
	 * @param {LightboxImage} image
	 * @param {ImageModel} imageData
	 */
	setTitle( image, imageData ) {
		let title;

		if ( image.caption ) {
			title = image.caption;
		} else if ( imageData.description ) {
			title = imageData.description;
		} else {
			title = image.filePageTitle.getNameText();
		}

		this.title.set( title );
	}

	/**
	 * Sets the file name in the panel.
	 *
	 * @param {string} filename The file name to set, without prefix
	 */
	setFileName( filename ) {
		this.$filenamePrefix.text(
			mw.config.get( 'wgFormattedNamespaces' )[
				mw.config.get( 'wgNamespaceIds' ).file
			] + ':'
		);
		this.$filename.text( filename );

		this.$filenameLi.removeClass( 'empty' );
	}

	/**
	 * Set source and author.
	 *
	 * @param {string} attribution Custom attribution string
	 * @param {string} source With unsafe HTML
	 * @param {string} author With unsafe HTML
	 * @param {number} authorCount
	 * @param {string} filepageUrl URL of the file page (used when other data is not available)
	 */
	setCredit( attribution, source, author, authorCount, filepageUrl ) {
		// sanitization will be done by TruncatableTextField.set()
		if ( attribution && ( authorCount <= 1 || !authorCount ) ) {
			this.creditField.set( this.wrapAttribution( attribution ) );
		} else if ( author && source ) {
			this.creditField.set(
				mw.message(
					'multimediaviewer-credit',
					this.wrapAuthor( author, authorCount, filepageUrl ),
					this.wrapSource( source )
				).plain()
			);
		} else if ( author ) {
			this.creditField.set( this.wrapAuthor( author, authorCount, filepageUrl ) );
		} else if ( source ) {
			this.creditField.set( this.wrapSource( source ) );
		} else {
			this.creditField.set(
				$( '<a>' )
					.addClass( 'mw-mmv-credit-fallback' )
					.prop( 'href', filepageUrl )
					.text( mw.message( 'multimediaviewer-credit-fallback' ).plain() )
					.get( 0 ).outerHTML
			);
		}

		this.$credit.removeClass( 'empty' );
	}

	/**
	 * Wraps a source string it with MediaViewer styles
	 *
	 * @param {string} source Warning - unsafe HTML sometimes goes here
	 * @return {string} unsafe HTML
	 */
	wrapSource( source ) {
		return $( '<span>' )
			.addClass( 'mw-mmv-source' )
			.append( $.parseHTML( source ) )
			.get( 0 ).outerHTML;
	}

	/**
	 * Wraps an author string with MediaViewer styles
	 *
	 * @param {string} author Warning - unsafe HTML sometimes goes here
	 * @param {number} authorCount
	 * @param {string} filepageUrl URL of the file page (used when some author data is not available)
	 * @return {string} unsafe HTML
	 */
	wrapAuthor( author, authorCount, filepageUrl ) {
		const $wrapper = $( '<span>' )
			.addClass( 'mw-mmv-author' );

		if ( authorCount > 1 ) {
			const $moreLink = $( '<a>' )
				.addClass( 'mw-mmv-more-authors' )
				.text( mw.msg( 'multimediaviewer-multiple-authors', authorCount - 1 ) )
				.attr( 'href', filepageUrl );
			$wrapper.append( mw.message(
				'multimediaviewer-multiple-authors-combine',
				$( $.parseHTML( author ) ),
				$moreLink
			).parseDom() );
		} else {
			$wrapper.append( author );
		}

		return $wrapper.get( 0 ).outerHTML;
	}

	/**
	 * Wraps an attribution string with MediaViewer styles
	 *
	 * @param {string} attribution Warning - unsafe HTML sometimes goes here
	 * @return {string} unsafe HTML
	 */
	wrapAttribution( attribution ) {
		return $( '<span>' )
			.addClass( 'mw-mmv-author' )
			.addClass( 'mw-mmv-source' )
			.append( $.parseHTML( attribution ) )
			.get( 0 ).outerHTML;
	}

	/**
	 * Sets the license display in the panel
	 *
	 * @param {License|null} license license data (could be missing)
	 * @param {string} filePageUrl URL of the file description page
	 */
	setLicense( license, filePageUrl ) {
		let shortName;
		let url;
		let isCc;
		let isPd;

		filePageUrl += `?uselang=${ mw.config.get( 'wgUserLanguage' ) }#${ mw.msg( 'license-header' ) }`;

		if ( license ) {
			shortName = license.getShortName();
			url = license.deedUrl || filePageUrl;
			isCc = license.isCc();
			isPd = license.isPd();
		} else {
			shortName = mw.msg( 'multimediaviewer-license-default' );
			url = filePageUrl;
			isCc = isPd = false;
		}

		this.$license
			.text( shortName )
			.prop( 'href', url )
			.prop( 'target', license && license.deedUrl ? '_blank' : '' );

		this.$licenseLi
			.toggleClass( 'cc-license', isCc )
			.toggleClass( 'pd-license', isPd )
			.removeClass( 'empty' );
	}

	/**
	 * Set an extra permission text which should be displayed.
	 *
	 * @param {string} permission
	 */
	setPermission( permission ) {
		this.$permissionLink.show();
		this.permission.set( permission );
	}

	/**
	 * Sets any special restrictions that should be displayed.
	 *
	 * @param {string[]} restrictions Array of restrictions
	 */
	setRestrictions( restrictions ) {
		const restrictionsSet = {};
		let showDefault = false;
		let validRestrictions = 0;

		restrictions.forEach( ( value, index ) => {
			// The following messages are used here:
			// * multimediaviewer-restriction-2257
			// * multimediaviewer-restriction-aus-reserve
			// * multimediaviewer-restriction-communist
			// * multimediaviewer-restriction-costume
			// * multimediaviewer-restriction-currency
			// * multimediaviewer-restriction-design
			// * multimediaviewer-restriction-fan-art
			// * multimediaviewer-restriction-ihl
			// * multimediaviewer-restriction-insignia
			// * multimediaviewer-restriction-ita-mibac
			// * multimediaviewer-restriction-nazi
			// * multimediaviewer-restriction-personality
			// * multimediaviewer-restriction-trademarked
			// * multimediaviewer-restriction-default
			// * multimediaviewer-restriction-default-and-others
			if ( !mw.message( `multimediaviewer-restriction-${ value }` ).exists() || value === 'default' || index + 1 > MetadataPanel.MAX_RESTRICT ) {
				showDefault = true; // If the restriction isn't defined or there are more than MAX_RESTRICT of them, show a generic symbol at the end
				return;
			}
			if ( restrictionsSet[ value ] ) {
				return; // Only show one of each symbol
			} else {
				restrictionsSet[ value ] = true;
			}

			this.$restrictions.append( this.createRestriction( value ) );
			validRestrictions++; // See how many defined restrictions are added so we know which default i18n msg to use
		} );

		if ( showDefault ) {
			if ( validRestrictions ) {
				this.$restrictions.append( this.createRestriction( 'default-and-others' ) );
			} else {
				this.$restrictions.append( this.createRestriction( 'default' ) );
			}
		}
	}

	/**
	 * Helper function that generates restriction labels
	 *
	 * @param {string} type Restriction type
	 * @return {jQuery} jQuery object of label
	 */
	createRestriction( type ) {
		mw.loader.using( 'mmv.ui.restriction', () => {} ); // for restriction icons
		const $label = $( '<span>' )
			.addClass( 'mw-mmv-label mw-mmv-restriction-label' )
			// Messages duplicated from above for linter
			// * multimediaviewer-restriction-2257
			// * multimediaviewer-restriction-aus-reserve
			// * multimediaviewer-restriction-communist
			// * multimediaviewer-restriction-costume
			// * multimediaviewer-restriction-currency
			// * multimediaviewer-restriction-design
			// * multimediaviewer-restriction-fan-art
			// * multimediaviewer-restriction-ihl
			// * multimediaviewer-restriction-insignia
			// * multimediaviewer-restriction-ita-mibac
			// * multimediaviewer-restriction-nazi
			// * multimediaviewer-restriction-personality
			// * multimediaviewer-restriction-trademarked
			// * multimediaviewer-restriction-default
			// * multimediaviewer-restriction-default-and-others
			.prop( 'title', mw.msg( `multimediaviewer-restriction-${ type }` ) );

		$( '<span>' )
			// The following classes are used here:
			// * mw-mmv-restriction-2257
			// * mw-mmv-restriction-aus-reserve
			// * mw-mmv-restriction-communist
			// * mw-mmv-restriction-costume
			// * mw-mmv-restriction-currency
			// * mw-mmv-restriction-design
			// * mw-mmv-restriction-fan-art
			// * mw-mmv-restriction-ihl
			// * mw-mmv-restriction-insignia
			// * mw-mmv-restriction-ita-mibac
			// * mw-mmv-restriction-nazi
			// * mw-mmv-restriction-personality
			// * mw-mmv-restriction-trademarked:after
			// * mw-mmv-restriction-default
			.addClass( `mw-mmv-restriction-label-inner mw-mmv-restriction-${ type === 'default-and-others' ? 'default' : type }` )
			.text( mw.msg( `multimediaviewer-restriction-${ type }` ) )
			.appendTo( $label );

		return $label;
	}

	/**
	 * Sets location data in the interface.
	 *
	 * @param {ImageModel} imageData
	 */
	setLocationData( imageData ) {
		if ( !imageData.hasCoords() ) {
			return;
		}

		/**
		 * Form at latitude or longitude as deg/min/sec array
		 *
		 * @param {number} value latitude or longitude
		 * @return {string[]} formatted deg/min/sec array
		 */
		function convertDegMinSec( value ) {
			value = Math.abs( value );
			const deg = Math.floor( value );
			value -= deg;
			const min = Math.floor( value * 60 );
			value -= min / 60;
			const sec = Math.round( value * 100 * 60 * 60 ) / 100;
			return [ deg, min, sec ].map( ( n ) => mw.language.convertNumber( n ) );
		}

		this.$location.text(
			mw.msg( 'multimediaviewer-geolocation',
				mw.msg( 'multimediaviewer-geoloc-coords',
					mw.msg( 'multimediaviewer-geoloc-coord',
						...convertDegMinSec( imageData.latitude ),
						// The following messages are used here:
						// * multimediaviewer-geoloc-north
						// * multimediaviewer-geoloc-south
						mw.msg( `multimediaviewer-geoloc-${ imageData.latitude >= 0 ? 'north' : 'south' }` )
					),

					mw.msg( 'multimediaviewer-geoloc-coord',
						...convertDegMinSec( imageData.longitude ),
						// The following messages are used here:
						// * multimediaviewer-geoloc-east
						// * multimediaviewer-geoloc-west
						mw.msg( `multimediaviewer-geoloc-${ imageData.longitude >= 0 ? 'east' : 'west' }` )
					)
				)
			)
		);

		this.$location.prop( 'href', (
			'https://geohack.toolforge.org/geohack.php?pagename=' +
			`${ imageData.title.getPrefixedText()
			}&params=${
				Math.abs( imageData.latitude ) }${ imageData.latitude >= 0 ? '_N_' : '_S_'
			}${ Math.abs( imageData.longitude ) }${ imageData.longitude >= 0 ? '_E_' : '_W_'
			}&language=${ encodeURIComponent( mw.config.get( 'wgUserLanguage' ) ) }`
		) );

		this.$locationLi.removeClass( 'empty' );
	}

	/**
	 * Set all the image information in the panel
	 *
	 * @param {LightboxImage} image
	 * @param {ImageModel} imageData
	 */
	setImageInfo( image, imageData ) {
		if ( imageData.creationDateTime ) {
			this.$datetimeCreated.text(
				mw.msg( 'multimediaviewer-datetime-created', this.formatDate( imageData.creationDateTime ) )
			);
			this.$datetimeCreatedLi.removeClass( 'empty' );
		}
		if ( imageData.uploadDateTime ) {
			this.$datetimeUpdated.text(
				mw.msg( 'multimediaviewer-datetime-uploaded', this.formatDate( imageData.uploadDateTime ) )
			);
			this.$datetimeUpdatedLi.removeClass( 'empty' );
		}

		this.buttons.set( image, imageData );
		this.description.set( imageData.description, image.caption );

		this.setLicense( imageData.license, imageData.descriptionUrl );

		this.setFileName( imageData.title.getMainText() );

		// these handle text truncation and should be called when everything that can push text down
		// (e.g. floated buttons) has already been laid out
		this.setTitle( image, imageData );
		this.setCredit( imageData.attribution, imageData.source, imageData.author, imageData.authorCount, imageData.descriptionUrl );

		if ( imageData.permission ) {
			this.setPermission( imageData.permission );
		}

		if ( imageData.restrictions ) {
			this.setRestrictions( imageData.restrictions );
		}

		this.setLocationData( imageData );

		this.resetTruncatedText();
		this.scroller.unfreezeHeight();
	}

	/**
	 * Show an error message, in case the data could not be loaded
	 *
	 * @param {string} title image title
	 * @param {string} error error message
	 */
	showError( title, error ) {
		this.$credit.text( mw.msg( 'multimediaviewer-metadata-error', error ) );
		this.$title.html( title );
	}

	/**
	 * Transforms a date string into localized, human-readable format.
	 * Unrecognized strings are returned unchanged.
	 *
	 * @param {string} dateString
	 * @return {string} formatted date
	 */
	formatDate( dateString ) {
		let lang = mw.config.get( 'wgUserLanguage' );
		if ( lang === 'en' || lang === 'qqx' ) {
			// prefer "D MMMM YYYY" format
			// avoid passing invalid "qqx" to native toLocaleString(),
			// which would cause developer's browser locale to be used,
			// and thus sometimes cause tests to fail.
			lang = 'en-GB';
		}
		if ( dateString.length === 4 ) {
			// assume yyyy
			return dateString;
		}
		const date = new Date( dateString );
		try {
			if ( date instanceof Date && !isNaN( date ) ) {
				return date.toLocaleString( lang, {
					day: 'numeric',
					month: 'long',
					year: 'numeric',
					timeZone: 'UTC'
				} );
			}
		} catch ( ignore ) { }
		// fallback to original date string
		return dateString;
	}

	/**
	 * Shows truncated text in the title and credit (this also rearranges the layout a bit).
	 */
	revealTruncatedText() {
		if ( this.$container.hasClass( 'mw-mmv-untruncated' ) ) {
			return;
		}
		this.$container.addClass( 'mw-mmv-untruncated' );
		this.title.grow();
		this.creditField.grow();
	}

	/**
	 * Undoes changes made by revealTruncatedText().
	 */
	hideTruncatedText() {
		if ( !this.$container.hasClass( 'mw-mmv-untruncated' ) ) {
			return;
		}
		this.title.shrink();
		this.creditField.shrink();
		this.$container.removeClass( 'mw-mmv-untruncated' );
	}

	/**
	 * Hide or reveal truncated text based on whether the panel is open. This is normally handled by
	 * MetadataPanelScroller, but when the panel is reset (e.g. on a prev/next event) sometimes the panel position can change without a panel , such as on a
	 * prev/next event; in such cases this function has to be called.
	 */
	resetTruncatedText() {
		if ( this.scroller.panelIsOpen() ) {
			this.revealTruncatedText();
		} else {
			this.hideTruncatedText();
		}
	}
}

/**
 * Maximum number of restriction icons before default icon is used
 *
 * @property {number} MAX_RESTRICT
 * @static
 */
MetadataPanel.MAX_RESTRICT = 4;

module.exports = MetadataPanel;
