import i18n from "i18next";
import { initReactI18next } from "react-i18next";
import en from "./en.json";
import arSa from "./ar-sa.json";

const STORAGE_KEY = "locale";
const DEFAULT_LOCALE = "ar-sa";
const SUPPORTED_LOCALES = ["ar-sa", "en"];

function normalizeLocale(value) {
  if (!value) {
    return DEFAULT_LOCALE;
  }
  const lowered = value.toLowerCase();
  if (lowered.startsWith("ar")) {
    return "ar-sa";
  }
  return "en";
}

function readStoredLocale() {
  if (typeof window === "undefined") {
    return null;
  }
  try {
    return window.localStorage.getItem(STORAGE_KEY);
  } catch (error) {
    return null;
  }
}

function writeStoredLocale(locale) {
  if (typeof window === "undefined") {
    return;
  }
  try {
    window.localStorage.setItem(STORAGE_KEY, locale);
  } catch (error) {
    // Ignore storage errors (private mode, blocked storage, etc.).
  }
}

function getInitialLocale() {
  const stored = readStoredLocale();
  if (stored) {
    return normalizeLocale(stored);
  }
  if (typeof navigator !== "undefined") {
    return normalizeLocale(navigator.language);
  }
  return DEFAULT_LOCALE;
}

function isRtl(locale) {
  return normalizeLocale(locale) === "ar-sa";
}

function applyDocumentLocale(locale) {
  if (typeof document === "undefined") {
    return;
  }
  const normalized = normalizeLocale(locale);
  document.documentElement.lang = normalized;
  document.documentElement.dir = isRtl(normalized) ? "rtl" : "ltr";
}

i18n.use(initReactI18next).init({
  resources: {
    en: { translation: en },
    "ar-sa": { translation: arSa },
  },
  lng: getInitialLocale(),
  fallbackLng: "en",
  interpolation: { escapeValue: false },
});

applyDocumentLocale(i18n.language);
i18n.on("languageChanged", applyDocumentLocale);

export function setLocale(locale) {
  const normalized = normalizeLocale(locale);
  writeStoredLocale(normalized);
  return i18n.changeLanguage(normalized);
}

export function getActiveLocale() {
  return i18n.language || DEFAULT_LOCALE;
}

export { DEFAULT_LOCALE, SUPPORTED_LOCALES, STORAGE_KEY };
export default i18n;