using Akka.Actor;

using Akka.Configuration;

using System.Threading.Tasks;

using System;

​

public class Program

{

    public static void Main()

    {

        // this configuration is required ony in .NET Fiddle

        var config = ConfigurationFactory.ParseString(@"akka.actor.default-dispatcher { type = ""Akka.Dispatch.TaskDispatcherConfigurator""}");

​

        var system = ActorSystem.Create("Sample", config);

​

        var actor = system.ActorOf<FreeBusyActor>();

​

        Task.Run(async () =>

        {

​

            for (var i = 0; i < 10; i++)

            {

                actor.Tell("get busy");

                await Task.Delay(40);

            }

            // alow some time for .NET Fiddle to flush

            await Task.Delay(500);

        }).Wait();

    }

​

    public class FreeBusyActor : ReceiveActor

    {

        public FreeBusyActor()

        {

            // the actor starts as "Free"

            Free();

        }

​

        void Free()

        {

            // when free, only "get busy" commands are handled

            Receive<string>(s => {

​

                if (s == "get busy")

                {

                    Console.WriteLine("Getting busy...");

​

                    // the actor becomes busy, so the next messages are handled differently

                    Become(Busy);

​

                    // the actor starts some work in the background

                    // when it's done tell itself it's free

                    Task.Delay(80).ContinueWith(_ => "you're free").PipeTo(Self, Self);

                }

            });

        }

​

        void Busy()

        {

            Receive<string>(s =>

            {

                // when busy, only accept messages from itself to get free

                if (s == "you're free" && Sender.Equals(Self))

                {

                    Console.WriteLine("Getting free...");

                    Become(Free);

                }

                // otherwise we won't do anything

                else

                {

                    Console.WriteLine("Not doing anything, I'm busy...");

                }

            });

        }

    }

}

​