/**
 * i18n.js 单元测试
 * 覆盖国际化系统：翻译 / 语言切换 / 插值 / 格式化 / 监听 / 持久化
 *
 * 注意：i18n.js 使用模块级状态（currentLocale / localeListeners / fallbackLocale），
 * 测试间需要重置状态以避免相互影响。
 */

import {
  i18nUtils,
  t,
  getCurrentLocale,
  setCurrentLocale,
  switchLocale,
  hasTranslation,
  getTranslations,
  addTranslations,
  getSupportedLocales,
  isLocaleSupported,
  getLocaleName,
  getLocaleDirection,
  formatNumber,
  formatCurrency,
  formatDate,
  addLocaleListener,
  removeLocaleListener,
  clearLocaleListeners,
  saveLocale,
  loadLocale,
  getDefaultLocale,
  initI18n,
  presetLocales,
  createI18nManager,
} from '../src/i18n.js';
import { LOCALES } from '../src/constants.js';

// 确保 localStorage 存在（jsdom 兼容）
if (typeof global.localStorage === 'undefined') {
  const store = {};
  global.localStorage = {
    getItem: (k) => (k in store ? store[k] : null),
    setItem: (k, v) => { store[k] = String(v); },
    removeItem: (k) => { delete store[k]; },
    clear: () => { Object.keys(store).forEach((k) => delete store[k]); },
  };
}

describe('当前语言', () => {
  beforeEach(() => {
    clearLocaleListeners();
    setCurrentLocale('zh-CN');
    localStorage.clear();
  });

  test('getCurrentLocale 默认 zh-CN', () => {
    expect(getCurrentLocale()).toBe('zh-CN');
  });

  test('setCurrentLocale 切换语言', () => {
    setCurrentLocale('en-US');
    expect(getCurrentLocale()).toBe('en-US');
  });

  test('setCurrentLocale 未知语言回退到 fallback', () => {
    const spy = jest.spyOn(console, 'warn').mockImplementation(() => {});
    setCurrentLocale('fr-FR');
    expect(spy).toHaveBeenCalled();
    expect(getCurrentLocale()).toBe('zh-CN');
    spy.mockRestore();
  });

  test('switchLocale 是 setCurrentLocale 的别名', () => {
    switchLocale('en-US');
    expect(getCurrentLocale()).toBe('en-US');
  });
});

describe('翻译函数 t', () => {
  beforeEach(() => {
    setCurrentLocale('zh-CN');
  });

  test('返回当前语言的翻译', () => {
    expect(t('bold')).toBe('粗体');
    expect(t('italic')).toBe('斜体');
  });

  test('切换语言后返回新语言翻译', () => {
    setCurrentLocale('en-US');
    expect(t('bold')).toBe('Bold');
    expect(t('italic')).toBe('Italic');
  });

  test('未知 key 返回 key 本身', () => {
    const spy = jest.spyOn(console, 'warn').mockImplementation(() => {});
    expect(t('non-existent-key')).toBe('non-existent-key');
    spy.mockRestore();
  });

  test('插值替换占位符', () => {
    // 临时添加带占位符的翻译
    addTranslations('zh-CN', { greeting: '你好，{name}！' });
    expect(t('greeting', { name: '爸爸' })).toBe('你好，爸爸！');
  });

  test('插值未提供占位符值时保留原占位符', () => {
    addTranslations('zh-CN', { greeting: '你好，{name}！' });
    expect(t('greeting', {})).toBe('你好，{name}！');
  });

  test('fallback 语言提供翻译', () => {
    // 临时切换到不存在的语言会回退；这里用 en-US 但 key 只在 zh-CN 中
    setCurrentLocale('en-US');
    // en-US 中也有 bold，所以构造一个只在 zh-CN 中的场景较难，
    // 改为直接验证：en-US 切换后 t('bold') 来自 en-US 而非 zh-CN
    expect(t('bold')).toBe('Bold');
  });
});

describe('翻译查询', () => {
  test('hasTranslation 已知 key 返回 true', () => {
    setCurrentLocale('zh-CN');
    expect(hasTranslation('bold')).toBe(true);
    expect(hasTranslation('italic')).toBe(true);
  });

  test('hasTranslation 未知 key 返回 false', () => {
    expect(hasTranslation('non-existent')).toBe(false);
  });

  test('getTranslations 返回指定语言的翻译对象', () => {
    const tr = getTranslations('zh-CN');
    expect(tr.bold).toBe('粗体');
    expect(tr.italic).toBe('斜体');
  });

  test('getTranslations 未知语言返回空对象', () => {
    expect(getTranslations('fr-FR')).toEqual({});
  });
});

describe('添加翻译', () => {
  beforeEach(() => {
    setCurrentLocale('zh-CN');
  });

  test('addTranslations 添加新语言', () => {
    addTranslations('ja', { bold: '太字' });
    expect(LOCALES.ja).toBeDefined();
    expect(LOCALES.ja.bold).toBe('太字');
    setCurrentLocale('ja');
    expect(t('bold')).toBe('太字');
    // 清理
    delete LOCALES.ja;
  });

  test('addTranslations 深度合并到已有语言', () => {
    addTranslations('zh-CN', { customKey: '自定义值' });
    expect(LOCALES['zh-CN'].customKey).toBe('自定义值');
    // 原有 key 不受影响
    expect(LOCALES['zh-CN'].bold).toBe('粗体');
    delete LOCALES['zh-CN'].customKey;
  });
});

describe('语言支持查询', () => {
  test('getSupportedLocales 返回内置语言', () => {
    const locales = getSupportedLocales();
    expect(locales).toContain('zh-CN');
    expect(locales).toContain('en-US');
  });

  test('isLocaleSupported 已知语言返回 true', () => {
    expect(isLocaleSupported('zh-CN')).toBe(true);
    expect(isLocaleSupported('en-US')).toBe(true);
  });

  test('isLocaleSupported 未知语言返回 false', () => {
    expect(isLocaleSupported('fr-FR')).toBe(false);
    expect(isLocaleSupported('')).toBe(false);
  });
});

describe('语言元信息', () => {
  test('getLocaleName 返回语言显示名', () => {
    expect(getLocaleName('zh-CN')).toBe('简体中文');
    expect(getLocaleName('en-US')).toBe('English (US)');
    expect(getLocaleName('ja')).toBe('日本語');
  });

  test('getLocaleName 未知语言返回语言代码本身', () => {
    expect(getLocaleName('unknown')).toBe('unknown');
  });

  test('getLocaleDirection LTR 语言', () => {
    expect(getLocaleDirection('zh-CN')).toBe('ltr');
    expect(getLocaleDirection('en-US')).toBe('ltr');
  });

  test('getLocaleDirection RTL 语言', () => {
    expect(getLocaleDirection('ar')).toBe('rtl');
    expect(getLocaleDirection('he')).toBe('rtl');
    expect(getLocaleDirection('fa')).toBe('rtl');
  });
});

describe('格式化函数', () => {
  beforeEach(() => {
    setCurrentLocale('en-US');
  });

  test('formatNumber 格式化数字', () => {
    const r = formatNumber(1234567);
    expect(typeof r).toBe('string');
    expect(r).toContain('1');
    expect(r).toContain('234');
  });

  test('formatNumber 接受 options', () => {
    const r = formatNumber(0.5, { style: 'percent' });
    expect(r).toContain('50');
  });

  test('formatCurrency 格式化货币', () => {
    const r = formatCurrency(99.99, 'USD');
    expect(typeof r).toBe('string');
    expect(r).toContain('99');
  });

  test('formatDate 格式化日期', () => {
    const r = formatDate('2024-01-15');
    expect(typeof r).toBe('string');
    // 至少包含年份信息
    expect(r.length).toBeGreaterThan(0);
  });

  test('formatDate 接受 Date 对象', () => {
    const r = formatDate(new Date('2024-06-15'));
    expect(typeof r).toBe('string');
    expect(r.length).toBeGreaterThan(0);
  });

  test('formatNumber 无效输入回退为字符串', () => {
    const r = formatNumber('not-a-number');
    expect(typeof r).toBe('string');
  });
});

describe('语言监听', () => {
  beforeEach(() => {
    clearLocaleListeners();
    setCurrentLocale('zh-CN');
  });

  test('addLocaleListener 注册回调', () => {
    const fn = jest.fn();
    addLocaleListener(fn);
    setCurrentLocale('en-US');
    expect(fn).toHaveBeenCalledWith('en-US');
  });

  test('addLocaleListener 返回取消函数', () => {
    const fn = jest.fn();
    const unsub = addLocaleListener(fn);
    expect(typeof unsub).toBe('function');
    unsub();
    setCurrentLocale('en-US');
    expect(fn).not.toHaveBeenCalled();
  });

  test('removeLocaleListener 移除回调', () => {
    const fn = jest.fn();
    addLocaleListener(fn);
    removeLocaleListener(fn);
    setCurrentLocale('en-US');
    expect(fn).not.toHaveBeenCalled();
  });

  test('clearLocaleListeners 清空所有回调', () => {
    const fn1 = jest.fn();
    const fn2 = jest.fn();
    addLocaleListener(fn1);
    addLocaleListener(fn2);
    clearLocaleListeners();
    setCurrentLocale('en-US');
    expect(fn1).not.toHaveBeenCalled();
    expect(fn2).not.toHaveBeenCalled();
  });

  test('监听器抛错不影响其他监听器', () => {
    const errFn = jest.fn(() => { throw new Error('boom'); });
    const okFn = jest.fn();
    const spy = jest.spyOn(console, 'error').mockImplementation(() => {});
    addLocaleListener(errFn);
    addLocaleListener(okFn);
    setCurrentLocale('en-US');
    expect(errFn).toHaveBeenCalled();
    expect(okFn).toHaveBeenCalled();
    spy.mockRestore();
  });
});

describe('语言持久化', () => {
  beforeEach(() => {
    localStorage.clear();
    setCurrentLocale('zh-CN');
  });

  test('saveLocale 写入 localStorage', () => {
    saveLocale('en-US');
    expect(localStorage.getItem('metona-editor-locale')).toBe('en-US');
  });

  test('loadLocale 无保存时返回默认语言', () => {
    // 无保存时调用 getDefaultLocale
    const r = loadLocale();
    expect(typeof r).toBe('string');
    expect(r.length).toBeGreaterThan(0);
  });

  test('loadLocale 读取已保存值', () => {
    localStorage.setItem('metona-editor-locale', 'en-US');
    expect(loadLocale()).toBe('en-US');
  });

  test('initI18n 加载已保存的语言', () => {
    localStorage.setItem('metona-editor-locale', 'en-US');
    initI18n();
    expect(getCurrentLocale()).toBe('en-US');
  });
});

describe('默认语言探测', () => {
  test('getDefaultLocale 返回字符串', () => {
    const r = getDefaultLocale();
    expect(typeof r).toBe('string');
    expect(r.length).toBeGreaterThan(0);
  });

  test('navigator 不支持时返回 fallback', () => {
    const origNav = global.navigator;
    Object.defineProperty(global, 'navigator', { value: undefined, configurable: true });
    expect(getDefaultLocale()).toBe('zh-CN');
    Object.defineProperty(global, 'navigator', { value: origNav, configurable: true });
  });
});

describe('fallback 语言', () => {
  test('getFallbackLocale 默认 zh-CN', () => {
    expect(i18nUtils.getFallbackLocale()).toBe('zh-CN');
  });

  test('setFallbackLocale 修改 fallback', () => {
    i18nUtils.setFallbackLocale('en-US');
    expect(i18nUtils.getFallbackLocale()).toBe('en-US');
    // 恢复
    i18nUtils.setFallbackLocale('zh-CN');
  });
});

describe('i18nUtils 代理层', () => {
  test('暴露所有 i18n API', () => {
    [
      't', 'getCurrentLocale', 'setCurrentLocale', 'switchLocale',
      'getFallbackLocale', 'setFallbackLocale', 'hasTranslation',
      'getTranslations', 'addTranslations', 'getSupportedLocales',
      'isLocaleSupported', 'getLocaleName', 'getLocaleDirection',
      'formatNumber', 'formatCurrency', 'formatDate',
      'addLocaleListener', 'removeLocaleListener', 'clearLocaleListeners',
      'initI18n', 'saveLocale', 'loadLocale', 'getDefaultLocale',
    ].forEach((fn) => {
      expect(typeof i18nUtils[fn]).toBe('function');
    });
  });

  test('代理方法与具名导出一致', () => {
    expect(i18nUtils.t).toBe(t);
    expect(i18nUtils.getCurrentLocale).toBe(getCurrentLocale);
    expect(i18nUtils.switchLocale).toBe(switchLocale);
  });
});

describe('presetLocales', () => {
  test('包含 zh-CN 和 en-US', () => {
    expect(presetLocales['zh-CN']).toBeDefined();
    expect(presetLocales['en-US']).toBeDefined();
  });

  test('包含 name / nativeName / direction / translations', () => {
    const z = presetLocales['zh-CN'];
    expect(z.name).toBeDefined();
    expect(z.nativeName).toBeDefined();
    expect(z.direction).toBe('ltr');
    expect(z.translations).toBe(LOCALES['zh-CN']);
  });
});

describe('createI18nManager', () => {
  test('返回包含全部方法的管理器对象', () => {
    const m = createI18nManager();
    expect(typeof m.t).toBe('function');
    expect(typeof m.setCurrentLocale).toBe('function');
    expect(typeof m.formatNumber).toBe('function');
  });

  test('管理器方法可独立调用', () => {
    const m = createI18nManager();
    m.setCurrentLocale('en-US');
    expect(m.getCurrentLocale()).toBe('en-US');
    expect(m.t('bold')).toBe('Bold');
  });
});