session-desktop/ts/util/i18n/shared.ts

import { Locale } from 'date-fns';
import { CrowdinLocale } from '../../localization/constants';
import { timeLocaleMap } from './timeLocaleMap';
import { isUnitTest } from '../../shared/env_vars';

let mappedBrowserLocaleDisplayed = false;
let crowdinLocale: CrowdinLocale | undefined;
let browserLocale: string | undefined;

/**
 * Logs an i18n message to the console.
 * @param message - The message to log.
 * @deprecated we want to use a normal logger instead of this function, eventually.
 */
export function i18nLog(message: string) {
  // eslint-disable-next-line no-console
  console.log(`i18n: ${message}`);
}

export function getTimeLocaleDictionary() {
  return (timeLocaleMap as Record<string, Locale>)[getBrowserLocale()] || timeLocaleMap.en;
}

/**
 * Some users have a locale setup with a ':' in it.
 * When this happens, the full locale (i.e. the part with the "_") can sometimes be on the left, sometimes on the right.
 * This function will always return the part with the "_" if found, otherwise the full locale.
 */
export function keepFullLocalePart(locale: string) {
  const firstUnderscore = locale.indexOf('_');
  const firstDash = locale.indexOf('-');
  const firstSemiColon = locale.indexOf(':');
  if (firstSemiColon === -1) {
    return locale;
  }
  const firstUnderscoreOrDash = Math.max(firstUnderscore, firstDash);

  if (firstSemiColon > firstUnderscoreOrDash) {
    // the semicolon is after the underscore, so we return the start of the string (de_DE:en we return de_DE)
    return locale.substring(0, firstSemiColon);
  }

  // the semicolon is before the underscore, so we return the end of the string (in en:de_DE wew return de_DE)
  return locale.substring(firstSemiColon + 1);
}

/**
 * Returns the current locale as supported by Session (i.e. one generated by crowdin)
 */
export function getCrowdinLocale(): CrowdinLocale {
  if (!crowdinLocale) {
    i18nLog(`getCrowdinLocale: ${crowdinLocale}`);

    throw new Error('crowdinLocale is unset');
  }
  return crowdinLocale;
}

/**
 * Returns the closest supported locale by the browser.
 */
function getInitialBrowserLocale() {
  const parsedLocale = keepFullLocalePart(process.env.LANGUAGE || getCrowdinLocale() || 'en');

  // supportedLocalesOf will throw if the locales has a '_' instead of a '-' in it.
  const userLocaleDashed = parsedLocale.replaceAll('_', '-');

  try {
    let matchingLocales: Array<string> = [];
    try {
      matchingLocales = Intl.DateTimeFormat.supportedLocalesOf(userLocaleDashed);
    } catch (innerError) {
      // some users have a locale setup with a ':' in it.
      // see https://github.com/oxen-io/session-desktop/issues/3221
      const semiColonIndex = userLocaleDashed.indexOf(':');
      if (semiColonIndex > -1) {
        matchingLocales = Intl.DateTimeFormat.supportedLocalesOf(
          userLocaleDashed.substring(0, semiColonIndex)
        );
      }
    }

    const mappingTo = matchingLocales?.[0] || 'en';

    if (!mappedBrowserLocaleDisplayed) {
      mappedBrowserLocaleDisplayed = true;
      i18nLog(`userLocaleDashed: '${userLocaleDashed}', mapping to browser locale: ${mappingTo}`);
    }

    return mappingTo;
  } catch (e) {
    if (!mappedBrowserLocaleDisplayed) {
      mappedBrowserLocaleDisplayed = true;
      i18nLog(
        `userLocaleDashed: '${userLocaleDashed}' was an invalid locale for supportedLocalesOf(). Falling back to 'en'. Error:${e.message} `
      );
    }
    return 'en';
  }
}

export function getBrowserLocale() {
  if (!browserLocale) {
    browserLocale = getInitialBrowserLocale();
  }
  return browserLocale;
}

export function setInitialLocale(crowdinLocaleArg: CrowdinLocale) {
  if (crowdinLocale && !isUnitTest()) {
    i18nLog('setInitialLocale: crowdinLocale is already init');
  }
  crowdinLocale = crowdinLocaleArg;
}

export function isSessionLocaleSet() {
  return !!crowdinLocale;
}