using System;

public class Program

{

    public static void Main()

    {

        new CreateScheduledEventRequestHandler().Handle(new CreateScheduledEventRequest());

    }

}

​

public interface IScheduleInfoVisitor

{

    void Visit( IScheduleInfoHost host );

}

​

public interface IScheduleInfoHost

{

    void Host( RepeatingTask visitor );

    void Host( OneShotTask visitor );

}

​

public class CreateScheduledEventRequestHandler : IScheduleInfoHost

{

    public void Handle(CreateScheduledEventRequest request) => request.ScheduleInfo.Visit(this);

    public void Host( RepeatingTask visitor )

    {

        Console.WriteLine("Repeat every {0}", visitor.RepeatEvery);

    }

    public void Host( OneShotTask visitor )

    {

        Console.WriteLine("Run at {0}", visitor.RunAt);

    }

}

​

​

public record CreateScheduledEventRequest

{

    public ScheduleInfo ScheduleInfo = new OneShotTask();

}

​

public abstract record ScheduleInfo : IScheduleInfoVisitor

{

    public abstract void Visit( IScheduleInfoHost host );

}

​

public record RepeatingTask : ScheduleInfo

{

    public TimeSpan RepeatEvery;

    public override void Visit( IScheduleInfoHost host ) => host.Host(this);

}

​

public record OneShotTask : ScheduleInfo

{

    public DateTimeOffset RunAt;

    public override void Visit( IScheduleInfoHost host ) => host.Host(this);

}