using System;

using System.Threading;

using System.Threading.Tasks;

public class CashCorrectionEvent

{

    public string TradeSide { get; set; }

    public decimal Amount { get; set; }

}

​

public interface IEventsConsumer<T> : IDisposable

{

    Task<T> ConsumeAsync(CancellationToken token);

}

​

internal sealed class CashCorrectionEventsConsumer : IEventsConsumer<CashCorrectionEvent> 

{

    public Task<CashCorrectionEvent> ConsumeAsync(CancellationToken token) => Task.FromResult<CashCorrectionEvent>(new CashCorrectionEvent());

    public void Dispose() {}

}

​

public interface IEventRepository<T> : IDisposable

{

    Task AddAsync(T cashCorrectionEvent);

}

​

public class CashCorrectionEventRepository : IEventRepository<CashCorrectionEvent> 

{

    public Task AddAsync(CashCorrectionEvent cashCorrectionEvent) => Task.CompletedTask;

    public void Dispose() {}

}

​

//---------------------------------------------------------------------------------------------------------------------------------------------------------------------------

internal sealed class EventsListener

{

    private CashCorrectionEventRepository repository;

    private IEventsConsumer<CashCorrectionEvent> _eventsConsumer;

    public void Start()

    {

        repository = new CashCorrectionEventRepository();

        _eventsConsumer = new CashCorrectionEventsConsumer();

        Task.Run(() => ListenerRoutine());

    }

​

    private void ListenerRoutine()

    {

        while (true)

        {

            var cashCorrectionEvent = _eventsConsumer.ConsumeAsync(CancellationToken.None).Result;

            ValidateEvent(cashCorrectionEvent);

            repository.AddAsync(cashCorrectionEvent);

        }

    }

​

    private void ValidateEvent(CashCorrectionEvent cashCorrectionEvent)

    {

        if (cashCorrectionEvent.TradeSide == "BUY" && cashCorrectionEvent.Amount < 0) throw new Exception();

        if (cashCorrectionEvent.TradeSide == "SELL" && cashCorrectionEvent.Amount > 0) throw new Exception();

    }

​

    public void Dispose()

    {

        repository.Dispose();

        _eventsConsumer.Dispose();

    }

}