MediaWiki:Gadget-I18n-js.js

/* <nowiki>
 * Library for accessing i18n messages for use in Dev Wiki scripts.
 * See [[I18n-js]] for documentation.
 *
 * @author Cqm <https://dev.fandom.com/User:Cqm>
 * @author OneTwoThreeFall <https://dev.fandom.com/User:OneTwoThreeFall>
 *
 * @version 0.6.7
 *
 * @notes Also used by SOAP Wiki for their reporting forms (with a non-dev i18n.json page)
 * @notes This is apparently a commonly used library for a number of scripts and also
 *   includes a check to prevent double loading. This can make it painful to test from your
 *   JS console. To get around this, add ?usesitejs=0&useuserjs=0 to your URL.
 * @notes Coding convensions:
 *   https://www.mediawiki.org/wiki/Manual:Coding_conventions/JavaScript
 */

/* global mediaWiki */

/* jshint bitwise:true, camelcase:true, curly:true, eqeqeq:true, es3:false,
     forin:true, immed:true, indent:4, latedef:true, newcap:true,
     noarg:true, noempty:true, nonew:true, plusplus:true, quotmark:single,
     undef:true, unused:true, strict:true, trailing:true,
     browser:true, devel:false, jquery:true,
     onevar:true
 */

( function ( window, $, mw, undefined ) {
    'use strict';

    window.dev = window.dev || {};
    window.dev.i18n = window.dev.i18n || {};

    /* Prevent double loading and loss of cache */
    if ( window.dev.i18n.loadMessages !== undefined ) {
        return;
    }

    /*
     * Cache of mw config variables.
     *
     * @var {object} conf Cache of mw config variables:
     * - {boolean} debug
     * - {string} wgContentLanguage Site language
     *     Be careful to use this:
     *     - In languages with variants, this will block the language conversion;
     *       see <https://www.mediawiki.org/wiki/Writing_systems>.
     *     - In multilingual wikis like "Feed The Beast", this will block both the
     *       multilingual content providing and language conversion.
     * - {string} wgPageContentLanguage Page Language or Content Modal Language
     *     or Site Language or 'en'
     *     Be careful to use this:
     *     - In Special: pages, this will be the user language.
     *     - In Module: pages, this will be the content modal language 'en'.
     * - {string} wgUserLanguage
     * - {(string|null)} wgUserVariant The language variant user currently using,
     *     'null' when the page lannguage doesn't have language variants.
     */
    var conf = mw.config.get( [
        'debug',
        'wgContentLanguage',
        'wgPageContentLanguage',
        'wgUserLanguage',
        'wgUserVariant'
    ] ),

        /*
         * @var {number} Current time in milliseconds, used to set and check cache age.
         */
        now = Date.now(),

        /*
         * @var {number} Length of one day in milliseconds, used in cache age calculations.
         */
        oneDay = 1000 * 60 * 60 * 24,

        /*
         * @var {string} Prefix used for localStorage keys that contain i18n-js cache data
         */
        cachePrefix = 'i18n-cache-',

        /*
         * @var {boolean} Whether a fallback loop warning been shown
         */
        warnedAboutFallbackLoop = false,

        /*
         * @var {object} Cache of loaded I18n instances.
         */
        cache = {},

        /*
         * Initial overrides object, initialised below with the i18n global variable.
         * Allows end-users to override specific messages. See documentation for how to use.
         *
         * @var {(null|object)} overrides
         */
        overrides = null,

        /*
         * Mapping of deprecated language codes that were used in previous
         * versions of MediaWiki to up-to-date, current language codes.
         *
         * These codes shouldn't be used to store translations unless there are language
         * changes to /includes/language/LanguageCode.php in mediawiki/core.
         *
         * These may or may not be valid BCP 47 codes; they are included here
         * because MediaWiki renamed these particular codes at some point.
         *
         * Note that 'als' is actually a valid ISO 639 code (Tosk Albanian), but it
         * was previously used in MediaWiki for Alsatian, which comes under 'gsw'.
         *
         * @var {object.<string, string>} Mapping from deprecated MediaWiki-internal language code
         *   to replacement MediaWiki-internal language code.
         *
         * @see /includes/language/LanguageCode.php in MediaWiki core
         * @see https://meta.wikimedia.org/wiki/Special_language_codes
         */
        deprecatedCodes = {
            'als': 'gsw', // T25215
            'bat-smg': 'sgs', // T27522
            'be-x-old': 'be-tarask', // T11823
            'fiu-vro': 'vro', // T31186
            'roa-rup': 'rup', // T17988
            'zh-classical': 'lzh', // T30443
            'zh-min': 'nan',
            'zh-min-n': 'nan',
            'zh-min-nan': 'nan', // T30442
            'zh-yue': 'yue' // T30441
        },


        /**
         * Mapping of non-standard language codes used in MediaWiki to
         * standardized BCP 47 codes.
         *
         * @var {object.<string, string>} Mapping from nonstandard MediaWiki-internal codes to
         *   BCP 47 codes
         *
         * @see /includes/language/LanguageCode.php in MediaWiki core
         * @see https://meta.wikimedia.org/wiki/Special_language_codes
         * @see https://phabricator.wikimedia.org/T125073
         */
        nonStandardCodes = {
            'cbk-zam': 'cbk', // T124657
            'de-formal': 'de-x-formal',
            'eml': 'egl', // T36217
            'en-rtl': 'en-x-rtl',
            'es-formal': 'es-x-formal',
            'hu-formal': 'hu-x-formal',
            'kk-cn': 'kk-Arab-CN',
            'kk-kz': 'kk-Cyrl-KZ',
            'kk-tr': 'kk-Latn-TR',
            'map-bms': 'jv-x-bms', // [[wikipedia:en:Banyumasan_dialect]] T125073
            'mo': 'ro-Cyrl-MD', // T125073
            'nrm': 'nrf', // [[wikipedia:en:Norman_language]] T25216
            'nl-informal': 'nl-x-informal',
            'roa-tara': 'nap-x-tara', // [[wikipedia:en:Tarantino_dialect]]
            'simple': 'en-x-simple',
            'sr-ec': 'sr-Cyrl', // T117845
            'sr-el': 'sr-Latn', // T117845
            'zh-cn': 'zh-Hans-CN',
            'zh-sg': 'zh-Hans-SG',
            'zh-my': 'zh-Hans-MY',
            'zh-tw': 'zh-Hant-TW',
            'zh-hk': 'zh-Hant-HK',
            'zh-mo': 'zh-Hant-MO'
        },

        /*
         * Language fallbacks for those that don't fallback to English.
         *
         * Shouldn't need updating unless there're language fallback chain changes
         * to /languages/messages files in mediawiki/core.
         *
         * To generate this, use `$ grep -R "fallback =" /path/to/messages/`,
         * pipe the result to a text file and format the result.
         *
         * Please note that there's bidirectional/multidirectional fallback in languages,
         * including cdo <=> nan, pt <=> pt-br, zh <=> zh-hans <=> zh-hant
         *
         * @var {object.<string, string[]>} Mapping from language codes to fallback language codes
         */
        fallbacks = {
            'ab': [ 'ru' ],
            'abs': [ 'id' ],
            'ace': [ 'id' ],
            'ady': [ 'ady-cyrl' ],
            'aeb': [ 'aeb-arab' ],
            'aeb-arab': [ 'ar' ],
            'aln': [ 'sq' ],
            'alt': [ 'ru' ],
            'ami': [ 'zh-tw', 'zh-hant', 'zh', 'zh-hans' ],
            'an': [ 'es' ],
            'anp': [ 'hi' ],
            'arn': [ 'es' ],
            'arq': [ 'ar' ],
            'ary': [ 'ar' ],
            'arz': [ 'ar' ],
            'ast': [ 'es' ],
            'atj': [ 'fr' ],
            'av': [ 'ru' ],
            'avk': [ 'fr', 'es', 'ru' ],
            'awa': [ 'hi' ],
            'ay': [ 'es' ],
            'azb': [ 'fa' ],
            'ba': [ 'ru' ],
            'ban': [ 'id' ],
            'ban-bali': [ 'ban' ],
            'bar': [ 'de' ],
            'bbc': [ 'bbc-latn' ],
            'bbc-latn': [ 'id' ],
            'bcc': [ 'fa' ],
            'bci': [ 'fr' ],
            'be-tarask': [ 'be' ],
            'bgn': [ 'fa' ],
            'bh': [ 'bho' ],
            'bi': [ 'en' ],
            'bjn': [ 'id' ],
            'blk': [ 'my' ],
            'bm': [ 'fr' ],
            'bpy': [ 'bn' ],
            'bqi': [ 'fa' ],
            'br': [ 'fr' ],
            'btm': [ 'id' ],
            'bug': [ 'id' ],
            'bxr': [ 'ru' ],
            'ca': [ 'oc' ],
            'cbk-zam': [ 'es' ],
            'cdo': [ 'nan', 'zh-hant', 'zh', 'zh-hans' ],
            'ce': [ 'ru' ],
            'co': [ 'it' ],
            'crh': [ 'crh-latn' ],
            'crh-cyrl': [ 'ru' ],
            'cs': [ 'sk' ],
            'csb': [ 'pl' ],
            'cv': [ 'ru' ],
            'de-at': [ 'de' ],
            'de-ch': [ 'de' ],
            'de-formal': [ 'de' ],
            'dsb': [ 'hsb', 'de' ],
            'dtp': [ 'ms' ],
            'dty': [ 'ne' ],
            'egl': [ 'it' ],
            'eml': [ 'it' ],
            'es-formal': [ 'es' ],
            'ext': [ 'es' ],
            'ff': [ 'fr' ],
            'fit': [ 'fi' ],
            'fon': [ 'fr' ],
            'frc': [ 'fr' ],
            'frp': [ 'fr' ],
            'frr': [ 'de' ],
            'fur': [ 'it' ],
            'gag': [ 'tr' ],
            'gan': [ 'gan-hant', 'gan-hans', 'zh-hant', 'zh', 'zh-hans' ],
            'gan-hans': [ 'gan', 'gan-hant', 'zh-hans', 'zh', 'zh-hant' ],
            'gan-hant': [ 'gan', 'gan-hans', 'zh-hant', 'zh', 'zh-hans' ],
            'gcr': [ 'fr' ],
            'gl': [ 'pt' ],
            'gld': [ 'ru' ],
            'glk': [ 'fa' ],
            'gn': [ 'es' ],
            'gom': [ 'gom-deva' ],
            'gom-deva': [ 'hi' ],
            'gor': [ 'id' ],
            'gsw': [ 'de' ],
            'guc': [ 'es' ],
            'hak': [ 'zh-hant', 'zh', 'zh-hans' ],
            'hif': [ 'hif-latn' ],
            'hrx': [ 'de' ],
            'hsb': [ 'dsb', 'de' ],
            'hsn': [ 'zh-cn', 'zh-hans', 'zh', 'zh-hant' ],
            'ht': [ 'fr' ],
            'hu-formal': [ 'hu' ],
            'hyw': [ 'hy' ],
            'ii': [ 'zh-cn', 'zh-hans', 'zh', 'zh-hant' ],
            'inh': [ 'ru' ],
            'io': [ 'eo' ],
            'iu': [ 'ike-cans' ],
            'jam': [ 'en' ],
            'jut': [ 'da' ],
            'jv': [ 'id' ],
            'kaa': [ 'kk-latn', 'kk-cyrl' ],
            'kab': [ 'fr' ],
            'kbd': [ 'kbd-cyrl' ],
            'kbp': [ 'fr' ],
            'kea': [ 'pt' ],
            'khw': [ 'ur' ],
            'kiu': [ 'tr' ],
            'kjp': [ 'my' ],
            'kk': [ 'kk-cyrl' ],
            'kk-arab': [ 'kk-cyrl' ],
            'kk-cn': [ 'kk-arab', 'kk-cyrl' ],
            'kk-kz': [ 'kk-cyrl' ],
            'kk-latn': [ 'kk-cyrl' ],
            'kk-tr': [ 'kk-latn', 'kk-cyrl' ],
            'kl': [ 'da' ],
            'koi': [ 'ru' ],
            'ko-kp': [ 'ko' ],
            'krc': [ 'ru' ],
            'krl': [ 'fi' ],
            'ks': [ 'ks-arab' ],
            'ksh': [ 'de' ],
            'ksw': [ 'my' ],
            'ku': [ 'ku-latn' ],
            'kum': [ 'ru' ],
            'ku-arab': [ 'ckb' ],
            'kv': [ 'ru' ],
            'lad': [ 'es' ],
            'lb': [ 'de' ],
            'lbe': [ 'ru' ],
            'lez': [ 'ru', 'az' ],
            'li': [ 'nl' ],
            'lij': [ 'it' ],
            'liv': [ 'et' ],
            'lki': [ 'fa' ],
            'lld': [ 'it', 'rm', 'fur' ],
            'lmo': [ 'pms', 'eml', 'lij', 'vec', 'it' ],
            'ln': [ 'fr' ],
            'lrc': [ 'fa' ],
            'ltg': [ 'lv' ],
            'luz': [ 'fa' ],
            'lzh': [ 'zh-hant', 'zh', 'zh-hans' ],
            'lzz': [ 'tr' ],
            'mad': [ 'id' ],
            'mai': [ 'hi' ],
            'map-bms': [ 'jv', 'id' ],
            'mdf': [ 'myv', 'ru' ],
            'mg': [ 'fr' ],
            'mhr': [ 'mrj', 'ru' ],
            'min': [ 'id' ],
            'mnw': [ 'my' ],
            'mo': [ 'ro' ],
            'mrj': [ 'mhr', 'ru' ],
            'ms-arab': [ 'ms' ],
            'mwl': [ 'pt' ],
            'myv': [ 'mdf', 'ru' ],
            'mzn': [ 'fa' ],
            'nah': [ 'es' ],
            'nan': [ 'cdo', 'zh-hant', 'zh', 'zh-hans' ],
            'nap': [ 'it' ],
            'nb': [ 'nn' ],
            'nds': [ 'de' ],
            'nds-nl': [ 'nl' ],
            'nia': [ 'id' ],
            'nl-informal': [ 'nl' ],
            'nn': [ 'nb' ],
            'nrm': [ 'nrf', 'fr' ],
            'oc': [ 'ca', 'fr' ],
            'olo': [ 'fi' ],
            'os': [ 'ru' ],
            'pcd': [ 'fr' ],
            'pdc': [ 'de' ],
            'pdt': [ 'de' ],
            'pfl': [ 'de' ],
            'pih': [ 'en' ],
            'pms': [ 'it' ],
            'pnt': [ 'el' ],
            'pt': [ 'pt-br' ],
            'pt-br': [ 'pt' ],
            'pwn': [ 'zh-tw', 'zh-hant', 'zh', 'zh-hans' ],
            'qu': [ 'qug', 'es' ],
            'qug': [ 'qu', 'es' ],
            'rgn': [ 'it' ],
            'rmy': [ 'ro' ],
            'roa-tara': [ 'it' ],
            'rsk': [ 'sr-ec' ],
            'rue': [ 'uk', 'ru' ],
            'rup': [ 'ro' ],
            'ruq': [ 'ruq-latn', 'ro' ],
            'ruq-cyrl': [ 'mk' ],
            'ruq-latn': [ 'ro' ],
            'sa': [ 'hi' ],
            'sah': [ 'ru' ],
            'scn': [ 'it' ],
            'sco': [ 'en' ],
            'sdc': [ 'it' ],
            'sdh': [ 'cbk', 'fa' ],
            'se': [ 'nb', 'fi' ],
            'ses': [ 'fr' ],
            'se-fi': [ 'se', 'fi', 'sv' ],
            'se-no': [ 'se', 'nb', 'nn' ],
            'se-se': [ 'se', 'sv' ],
            'sg': [ 'fr' ],
            'sgs': [ 'lt' ],
            'sh': [ 'bs', 'sr-el', 'hr' ],
            'shi': [ 'fr' ],
            'shy': [ 'shy-latn' ],
            'shy-latn': [ 'fr' ],
            'sjd': [ 'ru' ],
            'sk': [ 'cs' ],
            'skr': [ 'skr-arab' ],
            'skr-arab': [ 'ur', 'pnb' ],
            'sli': [ 'de' ],
            'smn': [ 'fi' ],
            'sr': [ 'sr-ec' ],
            'srn': [ 'nl' ],
            'stq': [ 'de' ],
            'sty': [ 'ru' ],
            'su': [ 'id' ],
            'szl': [ 'pl' ],
            'szy': [ 'zh-tw', 'zh-hant', 'zh', 'zh-hans' ],
            'tay': [ 'zh-tw', 'zh-hant', 'zh', 'zh-hans' ],
            'tcy': [ 'kn' ],
            'tet': [ 'pt' ],
            'tg': [ 'tg-cyrl' ],
            'trv': [ 'zh-tw', 'zh-hant', 'zh', 'zh-hans' ],
            'tt': [ 'tt-cyrl', 'ru' ],
            'tt-cyrl': [ 'ru' ],
            'ty': [ 'fr' ],
            'tyv': [ 'ru' ],
            'udm': [ 'ru' ],
            'ug': [ 'ug-arab' ],
            'vec': [ 'it' ],
            'vep': [ 'et' ],
            'vls': [ 'nl' ],
            'vmf': [ 'de' ],
            'vmw': [ 'pt' ],
            'vot': [ 'fi' ],
            'vro': [ 'et' ],
            'wa': [ 'fr' ],
            'wls': [ 'fr' ],
            'wo': [ 'fr' ],
            'wuu': [ 'zh-hans', 'zh', 'zh-hant' ],
            'xal': [ 'ru' ],
            'xmf': [ 'ka' ],
            'yi': [ 'he' ],
            'yue': [ 'zh-hk', 'zh-hant', 'zh', 'zh-hans' ],
            'za': [ 'zh-hans', 'zh', 'zh-hant' ],
            'zea': [ 'nl' ],
            'zgh': [ 'kab' ],
            'zh': [ 'zh-hans', 'zh-hant', 'zh-cn', 'zh-tw', 'zh-hk' ],
            'zh-cn': [ 'zh-hans', 'zh', 'zh-hant' ],
            'zh-hans': [ 'zh-cn', 'zh', 'zh-hant' ],
            'zh-hant': [ 'zh-tw', 'zh-hk', 'zh', 'zh-hans' ],
            'zh-hk': [ 'zh-hant', 'zh-tw', 'zh', 'zh-hans' ],
            'zh-mo': [ 'zh-hk', 'zh-hant', 'zh-tw', 'zh', 'zh-hans' ],
            'zh-my': [ 'zh-sg', 'zh-hans', 'zh-cn', 'zh', 'zh-hant' ],
            'zh-sg': [ 'zh-hans', 'zh-cn', 'zh', 'zh-hant' ],
            'zh-tw': [ 'zh-hant', 'zh-hk', 'zh', 'zh-hans' ]
        };

    /*
     * Get the normalised IETF/BCP 47 language tag.
     * 
     * mediawiki.language.bcp47 doesn't handle deprecated language codes, and
     * some non-standard language codes are missed from LanguageCode.php, so
     * this function is added to override the behavior.
     *
     * @param {string} lang The language code to convert.
     * @return {string} The language code complying with BCP 47 standards.
     *
     * @see https://gerrit.wikimedia.org/r/c/mediawiki/core/+/376506/
     * @see /resources/src/mediawiki.language/mediawiki.language.js in MediaWiki core
     * @see /includes/language/LanguageCode.php in MediaWiki core
     */
    function bcp47( lang ) {
        if ( nonStandardCodes[ lang ] ) {
            return nonStandardCodes[ lang ];
        }

        if ( deprecatedCodes[ lang ] ) {
            return bcp47( deprecatedCodes[ lang ] );
        }

        /*
         * @var {string[]} formatted
         * @var {boolean} isFirstSegment Whether is the first segment
         * @var {boolean} isPrivate Whether the code of the segment is private use
         * @var {string[]} segments The segments of language code
         */
        var formatted,
            isFirstSegment = true,
            isPrivate = false,
            segments = lang.split( '-' );

        formatted = segments.map( function ( segment ) {
            /*
             * @var {string} newSegment The converted segment of language code
             */
            var newSegment;

            /* when previous segment is x, it is a private segment and should be lc */
            if ( isPrivate ) {
                newSegment = segment.toLowerCase();
            /* ISO 3166 country code */
            } else if ( segment.length === 2 && !isFirstSegment ) {
                newSegment = segment.toUpperCase();
            /* ISO 15924 script code */
            } else if ( segment.length === 4 && !isFirstSegment ) {
                newSegment = segment.charAt( 0 ).toUpperCase() + segment.substring( 1 ).toLowerCase();
            /* Use lowercase for other cases */
            } else {
                newSegment = segment.toLowerCase();
            }

            isPrivate = segment.toLowerCase() === 'x';
            isFirstSegment = false;

            return newSegment;
        } );

        return formatted.join( '-' );
    }

    /*
     * Log a warning message to the browser console if the language fallback chain is
     * about to start a loop. Only logs once to prevent flooding the browser console.
     *
     * @param {string} lang Language in use when loop was found.
     * @param {string[]} fallbackChain Array of languages involved in the loop.
     */
    function warnOnFallbackLoop( lang, fallbackChain ) {
        if ( warnedAboutFallbackLoop ) {
            return;
        }
        warnedAboutFallbackLoop = true;

        fallbackChain.push( lang );
        console.error( '[I18n-js] Duplicated fallback language found. Please leave a message at <https://dev.fandom.com/wiki/Talk:I18n-js> and include the following line: \nLanguage fallback chain:', fallbackChain.join( ', ' ) );
    }

    /*
     * Get a translation of a message from the messages object in the
     * requested language.
     *
     * @param {object} messages The message object to look translations up in.
     * @param {string} msgName The name of the message to get.
     * @param {string} lang The language to get the message in.
     * @param {string[]} fallbackChain Array of languages that have already been checked.
     *     Used to detect if the fallback chain is looping.
     * @return {(string|boolean)} The requested translation or `false` if no message could be found.
     */
    function getMsg( messages, msgName, lang, fallbackChain ) {
        if ( deprecatedCodes[ lang ] ) {
            return getMsg( messages, msgName, deprecatedCodes[ lang ], fallbackChain );
        }

        if ( messages[ lang ] && messages[ lang ][ msgName ] ) {
            return messages[ lang ][ msgName ];
        }

        if ( !fallbackChain ) {
            fallbackChain = [];
        }

        /*
         * @var {string} fallbackLang
         */
        for ( var fallbackLang of fallbacks[ lang ] ) {
            if ( messages[ fallbackLang ] && messages[ fallbackLang ][ msgName ] ) {
                return messages[ fallbackLang ][ msgName ];
            }

            if ( fallbackChain.indexOf( fallbackLang ) !== -1 ) {
                /*
                 * Duplicated language code in fallback list
                 * Try to find next fallback language from list
                 */
                warnOnFallbackLoop( fallbackLang, fallbackChain );
                continue;
            }
            fallbackChain.push( fallbackLang );
        }

        /* No more languages in fallback list - switch to English */
        if ( messages.en && messages.en[ msgName ] ) {
            return messages.en[ msgName ];
        }

        return false;
    }

    /*
     * Substitute arguments into the string, where arguments are represented
     * as $n where n > 0.
     *
     * @param {string} message The message to substitute arguments into
     * @param {array} arguments The arguments to substitute in.
     * @return {string} The resulting message.
     */
    function handleArgs( message, args ) {
        args.forEach( function ( elem, index ) {
            /*
             * @var {RegExp} rgx
             */
            var rgx = new RegExp( '\\$' + ( index + 1 ), 'g' );
            message = message.replace( rgx, elem );
        } );

        return message;
    }

    /*
     * Generate a HTML link using the supplied parameters.
     *
     * @param {string} href The href of the link which will be converted to
     *     '/wiki/href'.
     * @param {string} text The text and title of the link. If this is not supplied, it
     *     will default to href.
     * @param {boolean} hasProtocol True if the href parameter already includes the
     *     protocol (i.e. it begins with 'http://', 'https://', or '//').
     * @return {string} The generated link.
     */
    function makeLink( href, text, hasProtocol ) {
        text = text || href;
        href = hasProtocol ? href : mw.util.getUrl( href );

        text = mw.html.escape( text );
        href = mw.html.escape( href );

        return '<a href="' + href + '" title="' + text + '">' + text + '</a>';
    }

    /*
     * Allow basic inline HTML tags in wikitext.does not support <a> as that's handled by the
     * wikitext links instead.
     *
     * Supports the following tags:
     * - <i>
     * - <b>
     * - <s>
     * - <br>
     * - <em>
     * - <strong>
     * - <span>
     *
     * Supports the following tag attributes:
     * - title
     * - style
     * - class
     *
     * @param html
     * @return The sanitised HTML code.
     */
    function sanitiseHtml( html ) {
        /*
         * @var context
         */
        var context = document.implementation.createHTMLDocument( '' ),
            $html = $.parseHTML( html, /* document */ context, /* keepscripts */ false ),
            $div = $( '<div>', context ).append( $html ),
            allowedAttrs = [
                'title',
                'style',
                'class'
            ],
            allowedTags = [
                'i',
                'b',
                's',
                'br',
                'em',
                'strong',
                'span',
            ];

        $div.find( '*' ).each( function () {
            var $this = $( this ),
                tagname = $this.prop( 'tagName' ).toLowerCase(),
                attrs,
                array,
                style;

            if ( allowedTags.indexOf( tagname ) === -1 ) {
                mw.log( '[I18n-js] Disallowed tag in message: ' + tagname );
                $this.remove();
                return;
            }

            attrs = $this.prop( 'attributes' );
            array = Array.prototype.slice.call( attrs );

            array.forEach( function ( attr ) {
                if ( allowedAttrs.indexOf( attr.name ) === -1 ) {
                    mw.log( '[I18n-js] Disallowed attribute in message: ' + attr.name + ', tag: ' + tagname );
                    $this.removeAttr( attr.name );
                    return;
                }

                /* Make sure there's nothing nasty in style attributes */
                if ( attr.name === 'style' ) {
                    style = $this.attr( 'style' );

                    if ( style.indexOf( 'url(' ) > -1 ) {
                        mw.log( '[I18n-js] Disallowed url() in style attribute' );
                        $this.removeAttr( 'style' );

                    /* https://phabricator.wikimedia.org/T208881 */
                    } else if ( style.indexOf( 'var(' ) > -1 ) {
                        mw.log( '[I18n-js] Disallowed var() in style attribute' );
                        $this.removeAttr( 'style' );
                    }
                }
            } );
        } );

        return $div.prop( 'innerHTML' );
    }

    /*
     * Parse some basic wikitext into HTML. Also supports basic inline HTML tags.
     *
     * Will process:
     * - [url text]
     * - [[pagename]]
     * - [[pagename|text]]
     * - {{PLURAL:count|singular|plural}}
     * - {{GENDER:gender|masculine|feminine|neutral}}
     *
     * @param {string} message The message to process.
     * @return {string} The resulting string.
     */
    function parse( message ) {
        /* [url text] -> [$1 $2] */
        var urlRgx = /\[((?:https?:)?\/\/.+?) (.+?)\]/g,
            /* [[pagename]] -> [[$1]] */
            simplePageRgx = /\[\[([^|]*?)\]\]/g,
            /* [[pagename|text]] -> [[$1|$2]] */
            pageWithTextRgx = /\[\[(.+?)\|(.+?)\]\]/g,
            /* {{PLURAL:count|singular|plural}} -> {{PLURAL:$1|$2}} */
            pluralRgx = /\{\{PLURAL:(\d+)\|(.+?)\}\}/gi,
            /* {{GENDER:gender|masculine|feminine|neutral}} -> {{GENDER:$1|$2}} */
            genderRgx = /\{\{GENDER:([^|]+)\|(.+?)\}\}/gi;

        if ( message.indexOf( '<' ) > -1 ) {
            message = sanitiseHtml( message );
        }

        return message
            .replace( urlRgx, function ( _match, href, text ) {
                return makeLink( href, text, true );
            } )
            .replace( simplePageRgx, function ( _match, href ) {
                return makeLink( href );
            } )
            .replace( pageWithTextRgx, function ( _match, href, text ) {
                return makeLink( href, text );
            } )
            .replace( pluralRgx, function ( _match, count, forms ) {
                return mw.language.convertPlural( Number( count ), forms.split( '|' ) );
            } )
            .replace(genderRgx, function ( _match, gender, forms ) {
                return mw.language.gender( gender, forms.split( '|' ) );
            } );
    }

    /*
     * Create a new Message instance.
     *
     * @param {object} messages The message object to look translations up in.
     * @param {string} lang The language to get the message in.
     * @param {array} args Any arguments to substitute into the message, [0] is message name.
     * @param {string} name The name of the script the messages are for.
     * @return
     */
    function message( messages, lang, args, name ) {
        if ( !args.length ) {
            return;
        }

        /*
         * @var msgName
         * @var {string} descriptiveMsgName
         * @var {object} msg
         * @var {boolean} msgExists
         */
        var msgName = args.shift(),
            descriptiveMsgName = 'i18njs-' + name + '-' + msgName,
            msg = getMsg( messages, msgName, lang ),
            msgExists = msg !== false;

        if ( !msgExists ) {
            /* use name wrapped in < > for missing message, per MediaWiki convention */
            msg = '<' + descriptiveMsgName + '>';
        }

        if ( conf.wgUserLanguage === 'qqx' && msgExists ) {
            /* https://www.mediawiki.org/wiki/Help:System_message#Finding_messages_and_documentation */
            msg = '(' + descriptiveMsgName + ')';
        } else if ( overrides[ name ] && overrides[ name ][ msgName ] ) {
            /* if the message has been overridden, use that without checking the language */
            msg = overrides[ name ][ msgName ];
            msgExists = true;
        }

        if ( args.length ) {
            msg = handleArgs( msg, args );
        }

        return {
            /*
             * @return {boolean} Representing whether the message exists.
             */
            exists: msgExists,

            /*
             * Parse wikitext links in the message and return the result.
             *
             * @return {string} The resulting string.
             */
            parse: function () {
                /*
                 * Skip parsing if the message wasn't found; otherwise
                 * the sanitisation will mess with it.
                 */
                if ( !this.exists ) {
                    return this.escape();
                }

                return parse( msg );
            },

            /*
             * Escape any HTML in the message and return the result.
             *
             * @return {string} The resulting string.
             */
            escape: function () {
                return mw.html.escape( msg );
            },

            /*
             * Return the message as is.
             *
             * @return {string} The resulting string.
             */
            plain: function () {
                return msg;
            }
        };
    }

    /*
     * Create a new i18n object.
     *
     * @param {object} messages The message object to look translations up in.
     * @param {string} name The name of the script the messages are for.
     * @param {object} options Options set by the loading script.
     * @return {object}
     */
    function i18n( messages, name, options ) {
        var defaultLang = options.language,
            tempLang = null;

        return {
            /*
             * Set the default language.
             *
             * @deprecated since v0.6 (2020-08-25), no longer supported.
             */
            useLang: function () {
                console.warn( '[I18n-js] “useLang()” is no longer supported by I18n-js (used in “' + name + '”) - using user language.' );
                this.useUserLang();
            },

            /*
             * Set the language for the next msg call.
             *
             * @param {string} lang The language code to use for the next `msg` call.
             *
             * @return {object} The current object for use in chaining.
             */
            inLang: function (lang) {
                if ( !options.cacheAll ) {
                    console.warn( '[I18n-js] “inLang()” is not supported without configuring `options.cacheAll` (used in “' + name + '”) - using user language.' );
                    lang = options.language;
                }
                tempLang = lang;
                return this;
            },

            /*
             * Set the default language to the content language.
             */
            useContentLang: function () {
                defaultLang = conf.wgContentLanguage;
            },

            /*
             * Set the language for the next `msg` call to the content language.
             *
             * @return {object} The current object for use in chaining.
             */
            inContentLang: function () {
                tempLang = conf.wgContentLanguage;
                return this;
            },

            /*
             * Set the default language to the page language.
             */
            usePageLang: function () {
                defaultLang = conf.wgPageContentLanguage;
            },

            /*
             * Set the language for the next `msg` call to the page language.
             *
             * @return {object} The current object for use in chaining.
             */
            inPageLang: function () {
                tempLang = conf.wgPageContentLanguage;
                return this;
            },

            /*
             * Set the default language to the page view language.
             * This is also known as the user language variant.
             */
            usePageViewLang: function () {
                defaultLang = conf.wgUserVariant || conf.wgContentLanguage;
            },

            /*
             * Set the language for the next `msg` call to the page view language.
             * This is also known as the user language variant.
             *
             * @return {object} The current object for use in chaining.
             */
            inPageViewLang: function () {
                tempLang = conf.wgUserVariant || conf.wgContentLanguage;
                return this;
            },

            /*
             * Set the default language to the user's language.
             */
            useUserLang: function () {
                defaultLang = options.language;
            },

            /*
             * Set the language for the next msg call to the user's language.
             *
             * @return {object} The current object for use in chaining.
             */
            inUserLang: function () {
                tempLang = options.language;
                return this;
            },

            /*
             * Create a new instance of Message.
             *
             * @return {object}
             */
            msg: function () {
                var args = Array.prototype.slice.call( arguments ),
                    lang = defaultLang;

                if ( tempLang !== null ) {
                    lang = tempLang;
                    tempLang = null;
                }

                return message( messages, lang, args, name );
            },

            /*
             * For accessing the raw messages.
             * Scripts should not rely on it or any of its properties existing.
             */
            _messages: messages
        };
    }

    /*
     * Preprocess each message's fallback chain for the user and content languages.
     * This allows us to save only those messages needed to the cache.
     *
     * @param {string} name The name of the script the messages are for.
     * @param {object} messages The message object to look translations up in.
     * @param {object} options Options set by the loading script.
     */
    function optimiseMessages( name, messages, options ) {
        var existingLangs = cache[ name ] && cache[ name ]._messages._isOptimised,
            langs = [ options.language ],
            msgKeys = Object.keys( messages.en || {} ),
            optimised = {};

        if ( !msgKeys.length ) {
            /* No English messages, don't bother optimising */
            return messages;
        }

        /*
         * @var addMsgsForLanguage
         */
        var addMsgsForLanguage = function (lang) {
            if ( optimised[ lang ] ) {
                /* Language already exists */
                return;
            }

            optimised[ lang ] = {};

            msgKeys.forEach( function ( msgName ) {
                /*
                 * @var msg
                 */
                var msg = getMsg( messages, msgName, lang );

                if ( msg !== false ) {
                    optimised[ lang ][ msgName ] = msg;
                }
            } );
        };

        if ( langs.indexOf( conf.wgContentLanguage ) === -1 ) {
            langs.push( conf.wgContentLanguage );
        }

        /*
         * If cache exists and is optimised, preserve existing languages.
         * This allows an optimised cache even when using different
         * language wikis on same domain (i.e. sharing same cache).
         */
        if ( existingLangs ) {
            existingLangs.forEach( function ( lang ) {
                if ( langs.indexOf( lang ) === -1 ) {
                    langs.push( lang );
                }
            } );
        }

        langs.forEach( addMsgsForLanguage );

        /*
         * `cacheAll` is an array of message names for which translations
         * should not be optimised - save all translations of these messages
         */
        if ( Array.isArray( options.cacheAll ) ) {
            msgKeys = options.cacheAll;
            Object.keys( messages ).forEach( addMsgsForLanguage );
        }

        optimised._isOptimised = langs;

        return optimised;
    }

    /*
     * Check that the cache for a script exists and, if optimised, contains the necessary languages.
     *
     * @param {string} name The name of the script to check for.
     * @param {object} options Options set by the loading script.
     * @return {boolean} Whether the cache should be used.
     */
    function cacheIsSuitable( name, options ) {
        var messages = cache[ name ] && cache[ name ]._messages;

        /* Nothing in cache */
        if ( !messages ) {
            return false;
        }

        /*
         * Optimised messages missing user or content language.
         * We'll need to load from server in this case.
         */
        if (
            messages._isOptimised &&
            !( messages[ options.language ] && messages[ conf.wgContentLanguage ] )
        ) {
            return false;
        }

        return true;
    }

    /*
     * Remove out-of-date entries in the i18n cache (those older than two days).
     *
     * This can never be perfect: it will only work on wikis that are visited.
     */
    function removeOldCacheEntries() {
        var isCacheKey = new RegExp( '^(' + cachePrefix + '.+)-content$' ),
            storageKeys = [];

        try {
            storageKeys = Object.keys( localStorage );
        } catch ( e ) {}

        storageKeys.filter( function ( key ) {
            return isCacheKey.test( key );
        } ).forEach( function ( key ) {
            var keyPrefix = key.match( isCacheKey )[ 1 ],
                cacheTimestamp;

            try {
                cacheTimestamp = Number( localStorage.getItem( keyPrefix + '-timestamp' ) );
            } catch ( e ) {}

            if ( now - cacheTimestamp < oneDay * 2 ) {
                /* Cached within last two days, keep it */
                return;
            }

            try {
                localStorage.removeItem( keyPrefix + '-content' );
                localStorage.removeItem( keyPrefix + '-timestamp' );
                localStorage.removeItem( keyPrefix + '-version' );
            } catch ( e ) {}
        } );
    }

    /*
     * Strip block comments from a JSON string which are illegal under the JSON spec.
     * This is a bit basic, so will remove comments inside strings too.
     *
     * @param {string} json The JSON string.
     * @return {string} The JSON string after any comments have been removed.
     */
    function stripComments( json ) {
        json = json
            .trim()
            .replace( /\/\*[\s\S]*?\*\//g, '' );
        return json;
    }

    /*
     * Save messages string to local storage for caching.
     *
     * @param {string} name The name of the script the messages are for.
     * @param {object} json The JSON object.
     * @param {number} cacheVersion Cache version requested by the loading script.
     */
    function saveToCache( name, json, cacheVersion ) {
        /*
         * @var {string} keyPrefix
         */
        var keyPrefix = cachePrefix + name;

        /* Don't cache empty JSON */
        if ( Object.keys( json ).length === 0 ) {
            return;
        }

        try {
            localStorage.setItem( keyPrefix + '-content', JSON.stringify( json ) );
            localStorage.setItem( keyPrefix + '-timestamp', now );
            localStorage.setItem( keyPrefix + '-version', cacheVersion || 0 );
        } catch ( e ) {}
    }

    /*
     * Parse JSON string loaded from page and create an i18n object.
     *
     * @param {string} name The name of the script the messages are for.
     * @param {string} res The JSON string.
     * @param {object} options Options set by the loading script.
     * @return {object} The resulting i18n object.
     */
    function parseMessagesToObject( name, res, options ) {
        var json = {},
            obj,
            msg;

        /* Handle parse errors gracefully */
        try {
            res = stripComments( res );
            json = JSON.parse( res );
        } catch ( e ) {
            msg = e.message;

            if ( msg === 'Unexpected end of JSON input' ) {
                msg += '. This may be caused by a non-existent i18n.json page.';
            }

            console.warn( '[I18n-js] SyntaxError in messages: ' + msg );
        }

        if (
            options.useCache &&
            !options.loadedFromCache &&
            options.cacheAll !== true
        ) {
            json = optimiseMessages( name, json, options );
        }

        obj = i18n( json, name, options );

        /* Cache the result in case it's used multiple times */
        cache[ name ] = obj;

        if ( !options.loadedFromCache ) {
            saveToCache( name, json, options.cacheVersion );
        }

        return obj;
    }

    /*
     * Load messages string from local storage cache and add to cache object.
     *
     * @param {string} name The name of the script the messages are for.
     * @param {object} options Options set by the loading script.
     */
    function loadFromCache( name, options ) {
        var keyPrefix = cachePrefix + name,
            cacheContent,
            cacheVersion;

        try {
            cacheContent = localStorage.getItem( keyPrefix + '-content' );
            cacheVersion = Number( localStorage.getItem( keyPrefix + '-version' ) );
        } catch ( e ) {}

        /* Cache exists, and its version is greater than or equal to requested version */
        if ( cacheContent && cacheVersion >= options.cacheVersion ) {
            options.loadedFromCache = true;
            parseMessagesToObject( name, cacheContent, options );
        }
    }

    /*
     * Load messages stored as JSON on a page.
     *
     * @param {string} name The name of the script the messages are for. This will be
     *     used to get messages from
     *     https://dev.fandom.com/wiki/MediaWiki:Custom-name/i18n.json.
     *   Use `u:<subdomain>` or `u:<language-path>.<subdomain>` to set other Fandom
     *   wikis as the source.
     * @param {object} options Options set by the loading script:
     * - {string} apiEndpoint: Use `u:<subdomain>` or `u:<language-path>.<subdomain>`
     *     to set other sites as the API endpoint of the source. Currently only
     *     support Fandom wikis.
     * - {string} page: Set other format of the full page name for the i18n JSON.
     *     Use $1 for the placeholder of name.
     * - {(array|boolean)} cacheAll: Either an array of message names for which translations should not be optimised,
     *     or `true` to disable the optimised cache.
     * - {number} cacheVersion: Minimum cache version requested by the loading script.
     * - {string} language: Set a default language for the script to use, instead of wgUserLanguage.
     * - noCache: Never load i18n from cache (not recommended for general use).
     *
     * @return {object} A jQuery.Deferred instance.
     */
    function loadMessages( name, options ) {
        /*
         * @var {object} deferred
         * @var {string} apiEndpoint
         * @var {RegExp} apiEndpointRgx
         * @var {string} page
         * @var {object} params
         */
        var deferred = $.Deferred(),
            customSource = name.match( /^u:(?:([a-z-]+)\.)?([a-z0-9-]+):/ ),
            apiEndpoint = 'https://dev.fandom.com/api.php',
            apiEndpointRgx = new RegExp(
                /* '^(https:\/\/(([a-z0-9-]+)\.fandom\.com(?:\/([a-z-]+))?|(([a-z-]+)\.wikipedia\.org\/w))\/api\.php)$' */
                '^(https:\/\/(([a-z0-9-]+)\.fandom\.com(?:\/([a-z-]+))?)\/api\.php)$'
            ),
            page = 'MediaWiki:Custom-' + name + '/i18n.json',
            params;

        options = options || {};
        if ( options.apiEndpoint && apiEndpointRgx.test( options.apiEndpoint ) ) {
            options.apiEndpoint = options.apiEndpoint;
        } else {
            options.apiEndpoint = apiEndpoint;
        }
        options.page = ( options.page && options.page.replace( /\$1/g, name ) ) || page;
        options.cacheVersion = Number( options.cacheVersion ) || 0;
        options.language = options.language || conf.wgUserLanguage;
        options.useCache = ( options.noCache || conf.debug ) !== true;

        if ( options.useCache ) {
            loadFromCache( name, options );

            if ( cacheIsSuitable( name, options ) ) {
                return deferred.resolve( cache[ name ] );
            }
        }

        /* Cache isn't suitable - loading from server */
        options.loadedFromCache = false;

        /*
         * Allow custom i18n pages to be specified on other wikis.
         * Mainly for SOAP Wiki to keep their own JSON file.
         * Note this only supports loading from wikis on fandom.com.
         */
        if ( customSource ) {
            apiEndpoint = apiEndpoint.replace( 'dev', customSource[ 2 ] );
            page = name.slice( customSource[ 0 ].length );

            // adjust endpoint when loading from interlanguage wiki
            if ( customSource[ 1 ] ) {
                apiEndpoint = apiEndpoint.replace(
                    /api\.php$/,
                    customSource[ 1 ] + '/$&'
                );
            }
        }

        params = {
            action: 'query',
            format: 'json',
            prop: 'revisions',
            rvprop: 'content',
            titles: page,
            indexpageids: 1,
            origin: '*',
            // Cache results for 5 minutes in CDN and browser
            maxage: 300,
            smaxage: 300
        };

        /*
         * 'site' and 'user' are dependencies so end-users can set overrides in their local JS
         * and have it take effect before we load the messages.
         * Generally, we will implicitly depend on those anyway due to where/when this is loaded.
         */
        mw.loader.using( [ 'mediawiki.language', 'mediawiki.util'/*, 'site', 'user'*/ ], function () {
            $.ajax( apiEndpoint, {
                data: params,
            } ).always( function ( data ) {
                var res = '',
                    revisionData = data.query && data.query.pages[ data.query.pageids[ 0 ] ].revisions;

                if ( revisionData ) {
                    res = revisionData[ 0 ][ '*' ];
                }

                deferred.resolve( parseMessagesToObject( name, res, options ) );
            } );
        } );

        return deferred;
    }

    /* Expose under the dev global */
    window.dev.i18n = $.extend( window.dev.i18n, {
        loadMessages: loadMessages,

        /*
         * "Hidden" functions to allow testing and debugging
         * they may be changed or removed without warning.
         * Scripts should not rely on these existing or their output being in any particular format.
         */
        _bcp47: bcp47,
        _stripComments: stripComments,
        _saveToCache: saveToCache,
        _getMsg: getMsg,
        _handleArgs: handleArgs,
        _parse: parse,
        _fallbacks: fallbacks,
        _cache: cache
    } );

    /* Initialise overrides object */
    window.dev.i18n.overrides = window.dev.i18n.overrides || {};
    overrides = window.dev.i18n.overrides;

    /*
     * Fire an event on load
     *
     * Alternatively, use $.getScript (or mw.loader)
     * and use the returned promise
     */
    mw.hook( 'dev.i18n' ).fire( window.dev.i18n );

    /* tidy the localStorage cache of old entries */
    removeOldCacheEntries();

} ( this, jQuery, mediaWiki ) );