frontend/src/i18n.ts

import i18n from 'i18next';
import { initReactI18next } from 'react-i18next';
import LanguageDetector from 'i18next-browser-languagedetector';

// Import translations
import enTranslation from './locales/en.json';
import zhTranslation from './locales/zh.json';

i18n
  // Detect user language
  .use(LanguageDetector)
  // Pass the i18n instance to react-i18next
  .use(initReactI18next)
  // Initialize i18next
  .init({
    resources: {
      en: {
        translation: enTranslation
      },
      zh: {
        translation: zhTranslation
      }
    },
    fallbackLng: 'en',
    debug: process.env.NODE_ENV === 'development',
    
    // Common namespace used for all translations
    defaultNS: 'translation',
    
    interpolation: {
      escapeValue: false, // React already safe from XSS
    },

    detection: {
      // Order of detection; prioritize localStorage to respect user language choice
      order: ['localStorage', 'cookie', 'htmlTag', 'navigator'],
      // Cache the language in localStorage
      caches: ['localStorage', 'cookie'],
    }
  });

export default i18n;