/* Translation lookup and locale-aware formatting. Copy lives in /locales/*.json. */
(() => {
  const dictionaries = window.LifeOSLocales || {};
  const en = dictionaries.en || {};
  const zh = dictionaries['zh-CN'] || {};
  const PREFERENCE_KEY = 'lifeos_language_preference_v1';
  const validPreference = value => ['auto', 'en', 'zh'].includes(value);
  const lookup = (object, path) => path.split('.').reduce((value, part) => value?.[part], object);
  const detectBrowserLanguage = () => {
    const preferences = navigator.languages?.length ? navigator.languages : [navigator.language || navigator.userLanguage || 'en'];
    return preferences.some(value => String(value).toLowerCase().startsWith('zh')) ? 'zh' : 'en';
  };
  const readPreference = () => {
    try {
      const saved = localStorage.getItem(PREFERENCE_KEY);
      if (validPreference(saved)) return saved;
      let oldSettings = {};
      try { oldSettings = JSON.parse(localStorage.getItem('lifeos_settings') || '{}'); } catch {}
      const legacyMode = oldSettings.languageMode ?? (['en', 'zh'].includes(oldSettings.language) ? 'manual' : 'auto');
      const migrated = legacyMode === 'manual' && ['en', 'zh'].includes(oldSettings.language) ? oldSettings.language : 'auto';
      localStorage.setItem(PREFERENCE_KEY, migrated);
      return migrated;
    } catch { return 'auto'; }
  };
  let preference = readPreference();
  const language = () => preference === 'auto' ? detectBrowserLanguage() : preference;

  function t(key, values = {}) {
    const selected = language() === 'zh' ? zh : en;
    const template = lookup(selected, key) ?? lookup(en, key) ?? key;
    return String(template).replace(/\{(\w+)\}/g, (_, name) => values[name] ?? `{${name}}`);
  }

  function locale() { return language() === 'zh' ? 'zh-CN' : 'en-US'; }
  function date(value, options) {
    const parsed = value instanceof Date ? value : new Date(typeof value === 'string' && /^\d{4}-\d{2}-\d{2}$/.test(value) ? `${value}T12:00:00` : value);
    return new Intl.DateTimeFormat(locale(), options).format(parsed);
  }
  function number(value, options) { return new Intl.NumberFormat(locale(), options).format(value); }
  function setLanguage(value) {
    if (!validPreference(value)) return;
    preference = value;
    try { localStorage.setItem(PREFERENCE_KEY, value); } catch {}
    window.renderIcons?.();
    window.renderAll?.();
    window.applyLanguage?.();
    window.toast?.(value === 'auto' ? (language() === 'zh' ? 'feedback.followingZh' : 'feedback.followingEn') : (value === 'zh' ? 'feedback.languageZh' : 'feedback.languageEn'));
  }

  window.lang = language;
  window.setLanguage = setLanguage;
  window.LifeI18n = { t, date, number, locale, language, preference: () => preference, dictionaries: { en, zh } };
})();