CreateRoomCommandHandler.cs

using DomeGym.Application.Common.Interfaces;
using DomeGym.Domain.RoomAggregate;

using ErrorOr;

using MediatR;

namespace DomeGym.Application.Rooms.Commands.CreateRoom;

public class CreateRoomCommandHandler : IRequestHandler<CreateRoomCommand, ErrorOr<Room>>
{
    private readonly ISubscriptionsRepository _subscriptionsRepository;
    private readonly IGymsRepository _gymsRepository;

    public CreateRoomCommandHandler(ISubscriptionsRepository subscriptionsRepository, IGymsRepository gymsRepository)
    {
        _subscriptionsRepository = subscriptionsRepository;
        _gymsRepository = gymsRepository;
    }

    public async Task<ErrorOr<Room>> Handle(CreateRoomCommand command, CancellationToken cancellationToken)
    {
        var gym = await _gymsRepository.GetByIdAsync(command.GymId);

        if (gym is null)
        {
            return Error.NotFound(description: "Gym not found");
        }

        var subscription = await _subscriptionsRepository.GetByIdAsync(gym.SubscriptionId);

        if (subscription is null)
        {
            return Error.Unexpected(description: "Subscription not found");
        }

        var room = new Room(
            name: command.RoomName,
            maxDailySessions: subscription.GetMaxDailySessions(),
            gymId: gym.Id);

        var addRoomResult = gym.AddRoom(room);

        if (addRoomResult.IsError)
        {
            return addRoomResult.Errors;
        }

        await _gymsRepository.UpdateAsync(gym);

        return room;
    }
}