/**
 * LandveX Gateway — HTTP Proxy
 * Routes requests to backend services
 */

import http from 'http';

export function proxyRequest(req, res, target) {
  const options = {
    hostname: target.host,
    port: target.port,
    path: req.url,
    method: req.method,
    headers: {
      ...req.headers,
      host: `${target.host}:${target.port}`,
    },
    timeout: 30000,
  };

  const proxyReq = http.request(options, (proxyRes) => {
    res.writeHead(proxyRes.statusCode || 500, proxyRes.headers);
    proxyRes.pipe(res);
  });

  proxyReq.on('error', (err) => {
    console.error(`[PROXY ERROR] ${target.name}: ${err.message}`);
    res.statusCode = 502;
    res.setHeader('Content-Type', 'application/json');
    res.end(JSON.stringify({
      error: 'Bad Gateway',
      service: target.name,
      message: err.message,
    }));
  });

  proxyReq.on('timeout', () => {
    proxyReq.destroy();
    res.statusCode = 504;
    res.setHeader('Content-Type', 'application/json');
    res.end(JSON.stringify({
      error: 'Gateway Timeout',
      service: target.name,
      message: 'Request timed out',
    }));
  });

  req.pipe(proxyReq);
}

export async function checkServiceHealth(service) {
  const start = Date.now();
  
  return new Promise((resolve) => {
    const req = http.request({
      hostname: service.host,
      port: service.port,
      path: service.healthPath,
      method: 'GET',
      timeout: 5000,
    }, (res) => {
      resolve({
        healthy: res.statusCode === 200,
        latency: Date.now() - start,
      });
    });

    req.on('error', (err) => {
      resolve({
        healthy: false,
        latency: Date.now() - start,
        error: err.message,
      });
    });

    req.on('timeout', () => {
      req.destroy();
      resolve({
        healthy: false,
        latency: Date.now() - start,
        error: 'Timeout',
      });
    });

    req.end();
  });
}