import { createI18n, type I18n, type I18nOptions } from 'vue-i18n';
import { SUPPORTED_LANGUAGE_CODES, SUPPORTED_LANGUAGES, NAMESPACES, type LanguageCode } from './constants';
import { resolveSupportedLanguage } from './resolver';

// 使用 import.meta.glob 动态加载所有语言文件
// 文件路径模式：./locales/{语言}/{命名空间}.json
const modules = import.meta.glob('./locales/*/*.json', { eager: true });

// 构建 vue-i18n 格式的资源对象：{ [locale]: { [namespace]: messages } }
function buildResources() {
  const resources: Record<string, Record<string, any>> = {};

  // 初始化每种语言的空对象
  SUPPORTED_LANGUAGE_CODES.forEach(lang => {
    resources[lang] = {};
  });

  // 遍历所有模块，按语言和命名空间组织
  for (const [path, module] of Object.entries(modules)) {
    // 路径示例：'./locales/en/common.json'
    const match = path.match(/\.\/locales\/([a-z]{2})\/([a-z]+)\.json$/);
    if (!match) continue;

    const [, lang, namespace] = match;
    if (!SUPPORTED_LANGUAGE_CODES.includes(lang as LanguageCode) || !NAMESPACES.includes(namespace as any)) {
      continue;
    }

    // @ts-expect-error: module 可能是 Module 类型
    const messages = (module as any).default || module;
    resources[lang][namespace] = messages;
  }

  return resources;
}

async function createI18nInstance() {
  const resources = buildResources();

  const options: I18nOptions = {
    legacy: false,
    locale: 'zh',
    fallbackLocale: 'zh',
    messages: resources, // 使用构建的资源对象
    availableLocales: SUPPORTED_LANGUAGE_CODES,
    fallbackFormat: true,
    datetimeFormats: {},
    numberFormats: {},
  };

  const i18n = createI18n(options);
  return i18n;
}

// 创建 i18n 实例
export const i18n = await createI18nInstance();

// 兼容性 API
export async function setLanguage(lang: LanguageCode, _i18n?: I18n) {
  const __i18n = _i18n ?? i18n;

  if (__i18n.mode === 'legacy') {
    __i18n.global.locale = lang;
    return;
  }

  (__i18n.global.locale as unknown as { value: LanguageCode }).value = lang;
}

export function getLanguage() {
  if (i18n.mode === 'legacy') {
    return i18n.global.locale;
  }
  
  return (i18n.global.locale as unknown as { value: LanguageCode }).value;
}

// 导出类型和常量
export type { LanguageCode };
export { SUPPORTED_LANGUAGE_CODES, SUPPORTED_LANGUAGES, NAMESPACES };
export default i18n;