import "server-only";
import { cache } from "react";
import { cookies, headers } from "next/headers";
import {
  detectLocale,
  languageCookie,
  localeTag,
  resolveLocale,
  translator,
  type LanguagePreference,
} from "@/shared/i18n";

export const getI18n = cache(async () => {
  const [jar, requestHeaders] = await Promise.all([cookies(), headers()]);
  const preference = jar.get(languageCookie)?.value;
  const locale = resolveLocale(
    preference,
    requestHeaders.get("accept-language"),
  );
  const languagePreference: LanguagePreference =
    preference === "en" || preference === "ru" ? preference : "auto";
  return {
    locale,
    preference: languagePreference,
    detectedLocale: detectLocale(requestHeaders.get("accept-language")),
    t: translator(locale),
    formatNumber: (value: number) => value.toLocaleString(localeTag(locale)),
    formatDate: (value: string) =>
      new Date(value).toLocaleDateString(localeTag(locale)),
  };
});