const express = require('express');
const { authenticate } = require('../middleware/auth');

const router = express.Router();

/**
 * GET /api/webrtc/ice-servers
 * Get ICE servers configuration (STUN/TURN) for WebRTC
 * Requires authentication
 */
router.get('/ice-servers', authenticate, async (req, res) => {
  try {
    const turnTokenId = process.env.CLOUDFLARE_TURN_TOKEN_ID;
    const turnApiToken = process.env.CLOUDFLARE_TURN_API_TOKEN;

    if (!turnTokenId || !turnApiToken) {
      console.error('Cloudflare TURN credentials not configured');
      // Fallback to public STUN servers if TURN not configured
      return res.json({
        success: true,
        iceServers: [
          { urls: 'stun:stun.l.google.com:19302' },
          { urls: 'stun:stun1.l.google.com:19302' },
        ],
      });
    }

    // Request TURN credentials from Cloudflare
    const cloudflareUrl = `https://rtc.live.cloudflare.com/v1/turn/keys/${turnTokenId}/credentials/generate`;

    const response = await fetch(cloudflareUrl, {
      method: 'POST',
      headers: {
        'Authorization': `Bearer ${turnApiToken}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        ttl: 86400, // 24 hours
      }),
    });

    if (!response.ok) {
      const errorText = await response.text();
      console.error('Cloudflare TURN API error:', response.status, errorText);

      // Fallback to public STUN servers
      return res.json({
        success: true,
        iceServers: [
          { urls: 'stun:stun.l.google.com:19302' },
          { urls: 'stun:stun1.l.google.com:19302' },
        ],
      });
    }

    const data = await response.json();

    // Cloudflare returns: { iceServers: { urls: [...], username: "...", credential: "..." } }
    // We need to return it in the format expected by RTCPeerConnection
    const cloudflareIceServers = data.iceServers;

    if (!cloudflareIceServers || !cloudflareIceServers.urls) {
      console.error('Invalid response from Cloudflare TURN API:', data);
      // Fallback to public STUN servers
      return res.json({
        success: true,
        iceServers: [
          { urls: 'stun:stun.l.google.com:19302' },
          { urls: 'stun:stun1.l.google.com:19302' },
        ],
      });
    }

    // Return in RTCPeerConnection format
    // Cloudflare provides all URLs (STUN + TURN) in one object with credentials
    res.json({
      success: true,
      iceServers: [
        {
          urls: cloudflareIceServers.urls,
          username: cloudflareIceServers.username,
          credential: cloudflareIceServers.credential,
        }
      ],
    });
  } catch (error) {
    console.error('Error fetching TURN credentials:', error);

    // Fallback to public STUN servers on error
    res.json({
      success: true,
      iceServers: [
        { urls: 'stun:stun.l.google.com:19302' },
        { urls: 'stun:stun1.l.google.com:19302' },
      ],
    });
  }
});

module.exports = router;