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

export function errorHandler(
  err: unknown,
  req: Request,
  res: Response,
  next: NextFunction
): void {
  if (err instanceof ZodError) {
    res.status(400).json({ error: 'Validation error', details: err.flatten() });
    return;
  }

  if (err instanceof Error) {
    const status = (err as NodeJS.ErrnoException & { status?: number }).status ?? 500;
    const message = status < 500 ? err.message : 'Internal server error';
    if (status >= 500) console.error(err);
    res.status(status).json({ error: message });
    return;
  }

  res.status(500).json({ error: 'Internal server error' });
}