import { NextFunction, Request, Response } from 'express';

/**
 * Custom AuthError class that extends Error with HTTP status code
 * Security: Provides consistent error handling for authentication issues
 */
export class AuthError extends Error {
  statusCode: number;

  constructor(message: string, statusCode: number = 401) {
    super(message);
    this.statusCode = statusCode;
    this.name = 'AuthError';
  }
}

/**
 * Middleware to handle AuthError exceptions
 * Security: Centralized error handling for authentication errors
 */
export const handleAuthError = (
  err: Error,
  req: Request,
  res: Response,
  next: NextFunction
) => {
  if (err instanceof AuthError) {
    return res.status(err.statusCode).json({
      error: err.message,
      statusCode: err.statusCode,
    });
  }

  // Handle JWT verification errors
  if (err.name === 'JsonWebTokenError' || err.name === 'TokenExpiredError') {
    return res.status(401).json({
      error: 'Invalid or expired token',
      statusCode: 401,
    });
  }

  next(err);
};