import type { Locale } from "vue-i18n";
import type { UserModule } from "~/types";
import { createI18n } from "vue-i18n";

// Import i18n resources
// https://vitejs.dev/guide/features.html#glob-import
const i18n = createI18n({
  legacy: false,
  locale: "",
  messages: {},
});

const localesMap = Object.fromEntries(
  Object.entries(import.meta.glob("../../locales/*.yml"))
    .map(([path, loadLocale]) => [path.match(/([\w-]*)\.yml$/)?.[1], loadLocale]),
) as Record<Locale, () => Promise<{ default: Record<string, string> }>>;

export const availableLocales = Object.keys(localesMap);

const loadedLanguages: string[] = [];

function setI18nLanguage(lang: Locale) {
  i18n.global.locale.value = lang as any;
  if (typeof document !== "undefined") {
    document.querySelector("html")?.setAttribute("lang", lang);
  }

  return lang;
}

export async function loadLanguageAsync(lang: string): Promise<Locale> {
  // If the same language
  if (i18n.global.locale.value === lang) {
    return setI18nLanguage(lang);
  }

  // If the language was already loaded
  if (loadedLanguages.includes(lang)) {
    return setI18nLanguage(lang);
  }

  // If the language hasn't been loaded yet
  const messages = await localesMap[lang]();
  i18n.global.setLocaleMessage(lang, messages.default);
  loadedLanguages.push(lang);
  return setI18nLanguage(lang);
}

export const install: UserModule = async ({ app }) => {
  app.use(i18n);
  await loadLanguageAsync(window.DEFAULT_LANG);
};