import { Request, Response, NextFunction } from 'express';
import logger from './logger';
import { ResponseHandler } from './responseHandler';

export class AppError extends Error {
  public statusCode: number;
  public isOperational: boolean;

  constructor(message: string, statusCode: number = 500) {
    super(message);
    this.statusCode = statusCode;
    this.isOperational = true;

    Error.captureStackTrace(this, this.constructor);
  }
}

export const errorHandler = (
  error: Error,
  req: Request,
  res: Response,
  _next: NextFunction
): void => {
  let statusCode = 500;
  let message = 'Internal Server Error';

  if (error instanceof AppError) {
    statusCode = error.statusCode;
    message = error.message;
  } else if (error.name === 'ValidationError') {
    statusCode = 400;
    message = 'Validation Error';
  } else if (error.name === 'UnauthorizedError') {
    statusCode = 401;
    message = 'Unauthorized';
  } else if (error.name === 'CastError') {
    statusCode = 400;
    message = 'Invalid ID format';
  } else if (error.name === 'MongoError' && (error as any).code === 11000) {
    statusCode = 400;
    message = 'Duplicate field value';
  }

  logger.error('Error occurred:', {
    error: error.message,
    stack: error.stack,
    statusCode,
    url: req.url,
    method: req.method,
    ip: req.ip,
  });

  ResponseHandler.error(res, message, statusCode, error.message);
};

export const notFoundHandler = (
  req: Request,
  _res: Response,
  next: NextFunction
): void => {
  const error = new AppError(`Route ${req.originalUrl} not found`, 404);
  next(error);
};

export const asyncHandler = (fn: Function) => {
  return (req: Request, res: Response, next: NextFunction) => {
    Promise.resolve(fn(req, res, next)).catch(next);
  };
};