/**
 * The locale table. Adding a language is this file, `xx.json`, and nothing else.
 *
 * Everything downstream reads from `LOCALES`: the Astro i18n config, the language
 * switcher, the hreflang set, the sitemap, the suggestion bar and the catalog loader.
 * There is deliberately no second list to keep in step.
 */

export const DEFAULT_LOCALE = 'en' as const;

export interface LocaleInfo {
  /** URL prefix and catalog filename. Also the value of `<html lang>`. */
  code: string;
  /**
   * The language's own name for itself, for the switcher. Never a flag: a flag is a
   * country, and Spanish is not Spain.
   */
  label: string;
  /**
   * BCP 47 tag handed to Intl. Region included because number and date formatting
   * differ by region even when the language does not.
   */
  intl: string;
  /** `og:locale`. Underscored, region required by the OpenGraph spec. */
  og: string;
  /** Writing direction for the document. */
  dir?: 'rtl';
}

/**
 * Order matters: this is the order the switcher renders in, and the default locale
 * comes first.
 */
export const LOCALES: LocaleInfo[] = [
  { code: 'en', label: 'English', intl: 'en-GB', og: 'en_US' },
  { code: 'es', label: 'Español', intl: 'es-ES', og: 'es_ES' },
  { code: 'nl', label: 'Nederlands', intl: 'nl-NL', og: 'nl_NL' },
  { code: 'zh', label: '简体中文', intl: 'zh-CN', og: 'zh_CN' },
  { code: 'hi', label: 'हिन्दी', intl: 'hi-IN', og: 'hi_IN' },
  { code: 'ar', label: 'العربية الفصحى', intl: 'ar-SA', og: 'ar_SA', dir: 'rtl' },
  { code: 'fr', label: 'Français', intl: 'fr-FR', og: 'fr_FR' },
  { code: 'pt', label: 'Português', intl: 'pt-BR', og: 'pt_BR' },
  { code: 'it', label: 'Italiano', intl: 'it-IT', og: 'it_IT' },
  { code: 'tr', label: 'Türkçe', intl: 'tr-TR', og: 'tr_TR' },
  { code: 'pl', label: 'Polski', intl: 'pl-PL', og: 'pl_PL' },
  { code: 'uk', label: 'Українська', intl: 'uk-UA', og: 'uk_UA' },
  { code: 'ro', label: 'Română', intl: 'ro-RO', og: 'ro_RO' },
  { code: 'el', label: 'Ελληνικά', intl: 'el-GR', og: 'el_GR' },
  { code: 'cs', label: 'Čeština', intl: 'cs-CZ', og: 'cs_CZ' },
  { code: 'sv', label: 'Svenska', intl: 'sv-SE', og: 'sv_SE' },
  { code: 'da', label: 'Dansk', intl: 'da-DK', og: 'da_DK' },
  { code: 'id', label: 'Bahasa Indonesia', intl: 'id-ID', og: 'id_ID' },
  { code: 'ur', label: 'اردو', intl: 'ur-PK', og: 'ur_PK', dir: 'rtl' },
  { code: 'ru', label: 'Русский', intl: 'ru-RU', og: 'ru_RU' },
  { code: 'de', label: 'Deutsch', intl: 'de-DE', og: 'de_DE' },
  { code: 'ja', label: '日本語', intl: 'ja-JP', og: 'ja_JP' },
  { code: 'ar-eg', label: 'العربية المصرية', intl: 'ar-EG', og: 'ar_EG', dir: 'rtl' },
  { code: 'vi', label: 'Tiếng Việt', intl: 'vi-VN', og: 'vi_VN' },
];

export type Locale = string;

/** Just the codes, for the Astro config and for validating a URL segment. */
export const LOCALE_CODES: string[] = LOCALES.map((l) => l.code);

/** Every locale except the default, which is the set that carries a URL prefix. */
export const PREFIXED_LOCALES: string[] = LOCALE_CODES.filter((code) => code !== DEFAULT_LOCALE);

export function isLocale(value: unknown): value is Locale {
  return typeof value === 'string' && LOCALE_CODES.includes(value);
}

export function localeInfo(locale: Locale): LocaleInfo {
  return LOCALES.find((l) => l.code === locale) ?? LOCALES[0]!;
}

/** The Intl tag for a locale, for `Intl.NumberFormat` and friends. */
export function intlTag(locale: Locale): string {
  return localeInfo(locale).intl;
}

/**
 * Namespaces whose keys are sent to the browser.
 *
 * Islands render strings at runtime, so their copy has to reach the client. The static
 * half of the site (home page sections, about, the legal pages) is rendered at build
 * time and its copy never needs to ship. Splitting on the namespace keeps the inline
 * payload to roughly a third of the catalog.
 *
 * `scripts/check-i18n.mjs` fails the build if an island reaches for a key outside this
 * list, so the split cannot silently rot into a missing string on a real page.
 */
export const CLIENT_NAMESPACES = [
  'common',
  'time',
  'status',
  'pulse',
  'mints',
  'mint',
  'nut',
  // The federation index's own count line, and the module names the live island
  // redraws when a fresh announcement disagrees with the build.
  'fedimints',
  'fedimint',
  'card',
  'reviews',
  'feed',
  'login',
  'signer',
  'notfound',
] as const;