using System;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.Hosting;

public class Program

{

    public static void Main()

    {

        using IHost host = Host.CreateDefaultBuilder()

             .ConfigureServices((_, services) =>

            {

                services.AddScoped<IEventHandler, Chain>();

                services.AddSingleton<App>();

            })

            .Build();

        using var scope = host.Services.CreateScope();

        var services = scope.ServiceProvider;

        services.GetRequiredService<App>().Run();

    }

}

​

public class App

{

    private readonly IEventHandler chain;

    public App(IEventHandler chain)

    {

        this.chain = chain;

    }

​

    public void Run()

    {

         chain.HandleEvent();

    }

}

​

public class Chain : IEventHandler

{

    public void HandleEvent()

    {

        // PROBLEMA

        // Cada step é instanciado, e no caso, os steps tem muitas de pendencias

        // INotificationCreator, IRosterTrackingRepository, ICrewControlPeriodService, IFeatureResolver, INotificationRepository  

        // IRosterVersionAssignmentRepository, ICrewMemberRemarkRepository

        // O Resultado seria

        /*

             var firstStep = new StepA(notificationCreator, rosterTrackingRepository);

​

            firstStep

                .SetNext(new StepB(notificationCreator, featureResolver))

                .SetNext(new StepC(notificationCreator, rosterTrackingRepository, crewControlPeriodService, featureResolver));

        */

        var firstStep = new StepA();

​

        firstStep

            .SetNext(new StepB())

            .SetNext(new StepC());

​

        firstStep.HandleEvent();

    }

}

​

public class StepA : StepBase

{

    public override void HandleEvent()

    {

        Console.WriteLine("Step A");

        Next.HandleEvent();

    }

}

​

public class StepB : StepBase

{

    public override void HandleEvent()

    {

        Console.WriteLine("Step B");

        Next.HandleEvent();

    }

}

​

public class StepC : StepBase

{

    public override void HandleEvent()

    {

        Console.WriteLine("Step C");

    }

}

​

public abstract class StepBase : IEventHandler

{

    protected IEventHandler Next { get; private set; }

​

    public abstract void HandleEvent();

​

    public StepBase SetNext(StepBase nextNode)

    {

        Next = nextNode;

        return nextNode;

    }

}

​

public interface IEventHandler

{

    void HandleEvent();

}

​

​

​

​

​