/**
 * 环信 SDK Node.js Polyfill 工具模块
 *
 * 提供 easemob-websdk 在 Node.js 下运行所需的浏览器 API 模拟。
 *
 * 用法：
 *   const { applyManualPolyfill, applyHappyDomPolyfill, printGlobalState } = require('./easemob-polyfill');
 *   applyManualPolyfill();
 */

// ──────────────────────────────────────────
// 手动 Polyfill：逐项注入缺失的浏览器 API
// ──────────────────────────────────────────
function applyManualPolyfill() {
  // window → globalThis（关键！让 typeof window === 'object'，SDK 据此判断浏览器环境）
  if (typeof globalThis.window === 'undefined') {
    globalThis.window = globalThis;
    console.log('  + window = globalThis');
  }

  // self → globalThis
  if (typeof globalThis.self === 'undefined') {
    globalThis.self = globalThis;
    console.log('  + self = globalThis');
  }

  // WebSocket → ws
  if (typeof globalThis.WebSocket === 'undefined') {
    try {
      const wsModule = require('ws');
      globalThis.WebSocket = wsModule.WebSocket || wsModule;
      console.log('  + WebSocket = ws (Node.js)');
    } catch {
      console.warn('  ! ws 包未安装，跳过 WebSocket polyfill');
    }
  }

  // localStorage → 内存 Map
  if (typeof globalThis.localStorage === 'undefined') {
    const store = new Map();
    globalThis.localStorage = {
      getItem: (key) => store.get(key) ?? null,
      setItem: (key, value) => { store.set(key, String(value)); },
      removeItem: (key) => { store.delete(key); },
      clear: () => { store.clear(); },
      get length() { return store.size; },
      key: (_index) => null,
    };
    console.log('  + localStorage = in-memory Map');
  }

  // XMLHttpRequest 由调用方按需注入（xhr2 / xmlhttprequest），此处不再自动注入

  // navigator 基本模拟
  if (typeof globalThis.navigator === 'undefined') {
    globalThis.navigator = {
      userAgent: 'Node.js',
      platform: process.platform,
      appName: 'Node.js',
      appVersion: process.version,
      language: 'zh-CN',
    };
    console.log('  + navigator = basic mock');
  }
}

// ──────────────────────────────────────────
// happy-dom Polyfill：注入完整浏览器环境
// ──────────────────────────────────────────
async function applyHappyDomPolyfill() {
  let happyDOM;
  try {
    happyDOM = require('happy-dom');
  } catch {
    console.error('  ✗ happy-dom 未安装');
    console.error('    请运行: npm install happy-dom --save-dev');
    process.exit(1);
  }

  // happy-dom v20+ uses Browser + BrowserContext API
  if (happyDOM.Browser && happyDOM.BrowserContext) {
    const browser = new happyDOM.Browser();
    const page = browser.newPage('https://a1.easemob.com');
    const window = page.mainFrame.window;
    const document = window.document;

    globalThis.window = window;
    globalThis.document = document;
    globalThis.self = window;
    globalThis.navigator = window.navigator;
    globalThis.localStorage = window.localStorage;
    globalThis.XMLHttpRequest = window.XMLHttpRequest;
    globalThis.WebSocket = window.WebSocket;
    globalThis.fetch = window.fetch.bind(window);
    globalThis.Headers = window.Headers;
    globalThis.Request = window.Request;
    globalThis.Response = window.Response;

    console.log('  + happy-dom Browser + BrowserContext ✓');
    console.log(`  + page URL: ${window.location.href}`);
    return;
  }

  // 旧版 GlobalRegistrator API (happy-dom < v15)
  const Registrator = happyDOM.GlobalRegistrator;
  if (Registrator && Registrator.register) {
    await Registrator.register();
    console.log('  + happy-dom GlobalRegistrator.register() ✓');
    return;
  }

  console.error('  ✗ happy-dom 版本不兼容，无法注入全局 API');
  console.error('    当前版本:', require('happy-dom/package.json').version);
  process.exit(1);
}

// ──────────────────────────────────────────
// 打印当前全局 API 状态
// ──────────────────────────────────────────
function printGlobalState() {
  const apis = [
    'self', 'WebSocket', 'localStorage', 'XMLHttpRequest',
    'navigator', 'fetch', 'window', 'document',
  ];
  console.log('\n  全局 API 状态:');
  for (const api of apis) {
    const exists = typeof globalThis[api] !== 'undefined';
    const type = typeof globalThis[api];
    console.log(`    ${exists ? '✓' : '✗'} ${api}: ${exists ? type : 'undefined'}`);
  }
}

module.exports = {
  applyManualPolyfill,
  applyHappyDomPolyfill,
  printGlobalState,
};