const express = require('express');
const axios = require('axios');
const app = express();
const port = 3000;

// Middleware to parse JSON
app.use(express.json());

// SSE proxy endpoint
app.get('/api/proxy/sse/events/orders/:orderId', async (req, res) => {
  try {
    // Get the order ID from the request parameters
    const orderId = req.params.orderId;

    // Get the auth header from the request
    const authHeader = req.headers['x-signed-auth'];

    // API base URL
    const apiBaseUrl = process.env.API_ENDPOINT || 'https://api.example.com';

    // Target URL
    const targetUrl = `${apiBaseUrl}/events/orders/${orderId}`;

    console.log(`Proxying SSE request to: ${targetUrl}`);

    // Create headers for the proxy request
    const headers = {
      'Accept': 'text/event-stream',
      'Cache-Control': 'no-cache',
    };

    // Add auth header if available
    if (authHeader) {
      headers['X-Signed-Auth'] = authHeader;
    }

    // Make the request to the target URL
    const response = await axios({
      method: 'GET',
      url: targetUrl,
      headers,
      responseType: 'stream',
      // Skip SSL certificate validation for development
      ...(process.env.NODE_ENV === 'development' && {
        httpsAgent: new (require('https').Agent)({ rejectUnauthorized: false })
      })
    });

    // Set headers for SSE
    res.setHeader('Content-Type', 'text/event-stream');
    res.setHeader('Cache-Control', 'no-cache');
    res.setHeader('Connection', 'keep-alive');

    // Copy other headers from the response
    for (const [key, value] of Object.entries(response.headers)) {
      if (key.toLowerCase() !== 'content-length') {
        res.setHeader(key, value);
      }
    }

    // Pipe the response stream to the client
    response.data.pipe(res);

    // Handle client disconnect
    req.on('close', () => {
      console.log(`Client disconnected from SSE for order ${orderId}`);
      response.data.destroy();
    });
  } catch (error) {
    console.error('Error in SSE proxy:', error);
    res.status(500).json({ error: 'Internal server error' });
  }
});

// Start the server
app.listen(port, () => {
  console.log(`SSE proxy server listening at http://localhost:${port}`);
});