WebAPISignalRChat/Backend/Diligent.WebAPI.Host/Mediator/Notifications/Handlers/DeleteNotificationHandler.cs

using Diligent.WebAPI.Business.Interfaces;
using Diligent.WebAPI.Host.Exceptions;
using Diligent.WebAPI.Host.Mediator.Notifications.Commands;
using MediatR;

namespace Diligent.WebAPI.Host.Mediator.Notifications.Handlers
{
    public class DeleteNotificationHandler : IRequestHandler<DeleteNotificationCommand, Unit>
    {
        private readonly ICustomerRepository _customerRepository;

        public DeleteNotificationHandler(ICustomerRepository customerRepository)
        {
            _customerRepository = customerRepository;
        }

        public async Task<Unit> Handle(DeleteNotificationCommand request, CancellationToken cancellationToken)
        {
            var user = await _customerRepository.GetCustomerById(request.NotificationData.UserId);

            if (user == null)
            {
                throw new NotFoundException();
            }

            var notification = user.Notifications.Where(x => x.RoomId == request.NotificationData.RoomId).FirstOrDefault();
            
            if (notification == null)
            {
                throw new NotFoundException();
            }

            await _customerRepository.DeleteNotification(user, notification);

            return new Unit();
        }
    }
}