// middleware/requestContext.js
/**
 * Request Context Middleware
 * 
 * Extracts and attaches request context information (IP, user agent, etc.)
 * This should be the FIRST middleware in the chain
 */

function requestContext(req, res, next) {
  // Extract client IP (considering proxies)
  req.clientIp = req.ip || 
                 req.headers['x-forwarded-for']?.split(',')[0]?.trim() || 
                 req.headers['x-real-ip'] || 
                 req.connection?.remoteAddress || 
                 'unknown';

  // Extract user agent
  req.userAgent = req.headers['user-agent'] || 'unknown';

  // Extract request ID for tracing (if not already set)
  req.requestId = req.headers['x-request-id'] || 
                  `${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;

  // Set request ID in response header
  res.setHeader('X-Request-Id', req.requestId);

  // Attach timestamp
  req.requestTimestamp = new Date();

  next();
}

export default requestContext;