import { createInstance, Namespace, FlatNamespace, KeyPrefix } from 'i18next';
import resourcesToBackend from 'i18next-resources-to-backend';
import { initReactI18next } from 'react-i18next/initReactI18next';
import { FallbackNs } from 'react-i18next';

import { getOptions } from '@/i18n/settings';

const initI18next = async (lng: string, ns: string | string[]) => {
  const i18nInstance = createInstance();
  await i18nInstance
    .use(initReactI18next)
    .use(
      resourcesToBackend(
        (language: string, namespace: string) =>
          import(`./locales/${language}/${namespace}.json`)
      )
    )
    .init(getOptions(lng, ns));
  return i18nInstance;
};

export async function useTranslation<
  Ns extends FlatNamespace,
  KPrefix extends KeyPrefix<FallbackNs<Ns>> = undefined,
>(lng: string, ns?: Ns, options: { keyPrefix?: KPrefix } = {}) {
  const i18nextInstance = await initI18next(
    lng,
    Array.isArray(ns) ? (ns as string[]) : (ns as string)
  );
  return {
    t: i18nextInstance.getFixedT(lng, ns, options.keyPrefix),
    i18n: i18nextInstance,
  };
}