import {
  ExceptionFilter,
  Catch,
  ArgumentsHost,
  HttpException,
} from '@nestjs/common';

import { Response } from 'express';

// In case of exception in middleware run before the CORS middleware (eg: JSON Middleware that checks the request body),
// the CORS headers are missing in the response.
// This class add CORS headers to exception response to avoid misleading CORS error
@Catch()
export class ApplyCorsToExceptions implements ExceptionFilter {
  catch(exception: any, host: ArgumentsHost) {
    const ctx = host.switchToHttp();
    const response = ctx.getResponse<Response>();

    if (!response.header) {
      return;
    }

    response.header('Access-Control-Allow-Origin', '*');
    response.header(
      'Access-Control-Allow-Methods',
      'GET,HEAD,PUT,PATCH,POST,DELETE',
    );
    response.header(
      'Access-Control-Allow-Headers',
      'Origin, X-Requested-With, Content-Type, Accept',
    );

    const status =
      exception instanceof HttpException ? exception.getStatus() : 500;

    response.status(status).json(exception.response);
  }
}