WebAPISignalRChat/Backend/Diligent.WebAPI.Host/Mediator/Rooms/Handlers/RemoveUserFromGroupHandler.cs

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

namespace Diligent.WebAPI.Host.Mediator.Chat.Handlers
{
    public class RemoveUserFromGroupHandler : IRequestHandler<RemoveUserFromGroupCommand, Unit>
    {
        private readonly IRoomRepository _roomRepository;

        public RemoveUserFromGroupHandler(IRoomRepository roomRepository)
        {
            _roomRepository = roomRepository;
        }

        public async Task<Unit> Handle(RemoveUserFromGroupCommand request, CancellationToken cancellationToken)
        {
            var room = await _roomRepository.GetByIdAsync(request.RoomId);

            if(room == null)
            {
                throw new NotFoundException("Room is not found");
            }

            var userConnection = room.Customers.Where(x => x.CustomerId == request.UserId).FirstOrDefault();

            if(userConnection == null)
            {
                throw new NotFoundException("User connection is not found");
            }

            await _roomRepository.LeaveChatRoom(room, userConnection);

            return new Unit();
        }
    }
}