const express = require('express');
const cors = require('cors');
const jwt = require('jsonwebtoken');
const { AccessToken } = require('twilio').jwt;
const { VideoGrant } = AccessToken;

const app = express();
const PORT = 3001;

// 中间件
app.use(cors());
app.use(express.json());

// Twilio 配置 - 请替换为您的实际凭证
const TWILIO_CONFIG = {
  accountSid: process.env.TWILIO_ACCOUNT_SID || 'AC_YOUR_ACCOUNT_SID',
  apiKey: process.env.TWILIO_API_KEY || 'SK3b25e00e6914162a7cf829cffc415cb3',
  apiSecret: process.env.TWILIO_API_SECRET || 'PpGH298dlRgMSeGrexUjw1flczTVIw9H',
};

// 生成 Twilio Access Token
app.post('/api/twilio/token', (req, res) => {
  try {
    const { identity, roomName } = req.body;

    if (!identity || !roomName) {
      return res.status(400).json({
        error: 'Identity and roomName are required'
      });
    }

    // 创建 Access Token
    const token = new AccessToken(
      TWILIO_CONFIG.accountSid,
      TWILIO_CONFIG.apiKey,
      TWILIO_CONFIG.apiSecret,
      { identity: identity }
    );

    // 创建 Video Grant
    const videoGrant = new VideoGrant({
      room: roomName
    });

    // 将 grant 添加到 token
    token.addGrant(videoGrant);

    // 生成 JWT token
    const jwtToken = token.toJwt();

    console.log(`Generated token for identity: ${identity}, room: ${roomName}`);

    res.json({
      token: jwtToken,
      identity: identity,
      roomName: roomName
    });

  } catch (error) {
    console.error('Token generation error:', error);
    res.status(500).json({
      error: 'Failed to generate token',
      details: error.message
    });
  }
});

// 健康检查端点
app.get('/health', (req, res) => {
  res.json({
    status: 'ok',
    timestamp: new Date().toISOString(),
    service: 'Twilio Token Server'
  });
});

// 获取房间信息（模拟）
app.get('/api/twilio/rooms', (req, res) => {
  res.json({
    rooms: [
      { name: 'test-room', participants: 0 },
      { name: 'demo-room', participants: 2 },
    ]
  });
});

// 启动服务器
app.listen(PORT, () => {
  console.log(`🚀 Twilio Token Server running on http://localhost:${PORT}`);
  console.log(`📋 Health check: http://localhost:${PORT}/health`);
  console.log(`🎥 Token endpoint: http://localhost:${PORT}/api/twilio/token`);
  console.log('');
  console.log('⚠️  请确保已设置正确的 Twilio 凭证:');
  console.log(`   TWILIO_ACCOUNT_SID: ${TWILIO_CONFIG.accountSid}`);
  console.log(`   TWILIO_API_KEY: ${TWILIO_CONFIG.apiKey}`);
  console.log(`   TWILIO_API_SECRET: ${TWILIO_CONFIG.apiSecret.substring(0, 4)}...`);
});

module.exports = app;