import { Request, Response, NextFunction } from 'express';
import { randomUUID } from 'crypto';
import { getLogger } from '../utils/logging.js';

/**
 * Generate a request ID
 * @returns A unique request ID
 */
export function generateRequestId(): string {
  return randomUUID();
}

/**
 * Extended Express Request with request ID
 */
export interface RequestWithId extends Request {
  id: string;
  startTime: number;
}

/**
 * Add request ID and timing to request object
 */
export function requestTracker(req: Request, res: Response, next: NextFunction): void {
  const requestId = req.headers['x-request-id'] || generateRequestId();
  const startTime = Date.now();
  
  // Add properties to request object
  (req as RequestWithId).id = String(requestId);
  (req as RequestWithId).startTime = startTime;
  
  // Add response header with request ID
  res.setHeader('x-request-id', requestId);
  
  // Create child logger with request ID
  const logger = getLogger().child({ requestId: String(requestId) });
  
  // Log request start
  logger.info(`${req.method} ${req.path}`, {
    method: req.method,
    path: req.path,
    query: req.query,
    headers: {
      'user-agent': req.headers['user-agent'],
      'content-type': req.headers['content-type'],
      'accept': req.headers['accept']
    },
    ip: req.ip
  });
  
  // Log response when finished
  res.on('finish', () => {
    const responseTime = Date.now() - startTime;
    
    logger.info(`${req.method} ${req.path} ${res.statusCode} ${responseTime}ms`, {
      method: req.method,
      path: req.path,
      statusCode: res.statusCode,
      responseTime,
      contentLength: res.getHeader('content-length')
    });
  });
  
  next();
}