CShare/backend/src/middleware/errorHandler.ts

import type { ErrorRequestHandler } from 'express';
import { ZodError } from 'zod';

export class HttpError extends Error {
  status: number;
  code: string;

  constructor(status: number, code: string, message: string) {
    super(message);
    this.status = status;
    this.code = code;
  }
}

export const notFoundHandler = () => {
  throw new HttpError(404, 'NOT_FOUND', 'Not found');
};

export const errorHandler: ErrorRequestHandler = (err, _req, res, _next) => {
  if (err instanceof ZodError) {
    res.status(400).json({
      error: 'Validation failed',
      code: 'VALIDATION_ERROR',
      details: err.flatten(),
    });
    return;
  }

  const status = err instanceof HttpError ? err.status : 500;
  const code = err instanceof HttpError ? err.code : 'INTERNAL_ERROR';
  const message = status === 500 ? 'Internal server error' : err.message;
  res.status(status).json({ error: message, code });
};