internal sealed class ExchangeFactory
{
    private readonly IContext _context;
    private readonly IServiceProvider _serviceProvider;
    private readonly int _retryAttempts;

    internal ExchangeFactory(IContext context, IServiceProvider serviceProvider, int retryAttempts)
    {
        _context = context;
        _serviceProvider = serviceProvider;
        _retryAttempts = retryAttempts;
    }

    internal PID CreateExchange(string exchange, string accountId)
    {
        Producer producer = exchange switch
        {
            "ftx" => () => ActivatorUtilities.CreateInstance<FtxSubscription>(_serviceProvider, accountId),
            "kraken" => () => ActivatorUtilities.CreateInstance<KrakenSubscription>(_serviceProvider, accountId),
            _ => throw new NotSupportedException()
        };

        var exchangeProps = Props.FromProducer(producer)
            .WithChildSupervisorStrategy(
                new OneForOneStrategy((_, _) => SupervisorDirective.Restart, _retryAttempts, null)
            );
        return _context.SpawnNamed(exchangeProps, $"{exchange}:{accountId}");
    }
}