api-error.ts

import { NextRequest, NextResponse } from 'next/server';

/**
 * A standardized error response format for the API.
 * @param message The error message.
 * @param status The HTTP status code.
 * @returns A NextResponse object with a standardized error body.
 */
export function apiErrorResponse(message: string, status: number) {
  return NextResponse.json({ error: message }, { status });
}

/**
 * Base class for custom API errors.
 * Allows bundling a message and an HTTP status code together.
 */
export class ApiError extends Error {
  public readonly status: number;
  constructor(message: string, status: number) {
    super(message);
    this.status = status;
  }
}

export class NotFoundError extends ApiError {
  constructor(message: string = 'Resource not found') {
    super(message, 404);
  }
}

export class BadRequestError extends ApiError {
  constructor(message: string = 'Bad request') {
    super(message, 400);
  }
}

export class UnauthorizedError extends ApiError {
  constructor(message: string = 'Unauthorized') {
    super(message, 401);
  }
}

// A type for API handlers to ensure consistency.
// Note: 'props' is 'any' to accommodate different route parameter structures.
type ApiHandler = (req: NextRequest, props: any) => Promise<NextResponse>;

/**
 * A higher-order function to wrap API route handlers with standardized error handling.
 * @param handler The API route handler function to wrap.
 * @returns A new handler function with built-in try-catch logic.
 */
export function withErrorHandler(handler: ApiHandler): ApiHandler {
  return async (req: NextRequest, props: any) => {
    try {
      return await handler(req, props);
    } catch (error) {
      if (error instanceof ApiError) {
        return apiErrorResponse(error.message, error.status);
      }

      // For unknown or unexpected errors, log them for debugging purposes.
      // In a real production environment, you would use a dedicated logging service.
      console.error('An unexpected error occurred:', error);

      // Return a generic 500 response to avoid leaking implementation details.
      return apiErrorResponse('An internal server error occurred', 500);
    }
  };
}