errors.ts

import { data } from 'react-router';

export class AppError extends Error {
  constructor(
    message: string,
    public statusCode: number = 500,
    public code?: string
  ) {
    super(message);
    this.name = 'AppError';
  }
}

export class ValidationError extends AppError {
  constructor(
    message: string,
    public fieldErrors: Record<string, string[]> = {}
  ) {
    super(message, 400, 'VALIDATION_ERROR');
    this.name = 'ValidationError';
  }
}

export class NotFoundError extends AppError {
  constructor(message = 'Not found') {
    super(message, 404, 'NOT_FOUND');
    this.name = 'NotFoundError';
  }
}
      
      


type HandlerFn<T> = (args: LoaderFunctionArgs | ActionFunctionArgs) => Promise<T>;

export function withErrorHandling<T>(handler: HandlerFn<T>) {
  return async (args: LoaderFunctionArgs | ActionFunctionArgs) => {
    try {
      return await handler(args);
    } catch (error) {
      if (error instanceof ValidationError) {
        return data(
          { error: error.message, fieldErrors: error.fieldErrors },
          { status: 400 }
        );
      }
      
      if (error instanceof NotFoundError) {
        throw new Response(error.message, { status: 404 });
      }
      
      if (error instanceof AppError) {
        return data(
          { error: error.message, code: error.code },
          { status: error.statusCode }
        );
      }
      
      // Unknown error - let it bubble to error boundary
      console.error('Unexpected error:', error);
      throw error;
    }
  };
}