import akka.actor.{Actor, ActorSystem, Props}

// 액터 정의
class HelloActor extends Actor {
  def receive: Receive = {
    case "hello" =>
      sender() ! "world"
    case msg =>
      println(s"Unknown message: $msg")
  }
}

// 메인 또는 테스트 앱
object HelloActorApp extends App {
  // 액터 시스템 생성
  val system = ActorSystem("HelloSystem")

  // 액터 인스턴스 생성

  val helloActor = system.actorOf(Props[HelloActor], name = "helloActor")

  // 응답을 기다릴 임시 액터 생성
  import akka.pattern.ask
  import akka.util.Timeout
  import scala.concurrent.duration._
  import scala.concurrent.Await
  import scala.concurrent.ExecutionContext.Implicits.global

  implicit val timeout: Timeout = Timeout(5.seconds)

  // 메시지 전송 및 응답 대기
  val future = helloActor ? "hello"
  val result = Await.result(future, timeout.duration)

  println(s"응답: $result") // "world" 출력

  // 종료
  system.terminate()
}

public class HelloActor extends AbstractActor {

    // 액터 생성 팩토리
    public static Props props() {
        return Props.create(HelloActor.class);
    }

    @Override
    public Receive createReceive() {
        return receiveBuilder()
            .matchEquals("hello", msg -> {
                getSender().tell("world", getSelf());
            })
            .matchAny(msg -> {
                System.out.println("Unknown message: " + msg);
            })
            .build();
    }
}

public class HelloActorApp {
    public static void main(String[] args) throws Exception {
        ActorSystem system = ActorSystem.create("HelloSystem");

        ActorRef helloActor = system.actorOf(HelloActor.props(), "helloActor");

        // 메시지 보내고 응답 기다리기
        Future<Object> future = Patterns.ask(helloActor, "hello", 5000);
        String result = (String) Await.result(future, Duration.create(5, TimeUnit.SECONDS));

        System.out.println("응답: " + result); // "world"

        system.terminate();
    }
}

public class HelloActor : ReceiveActor
{
    public HelloActor()
    {
        Receive<string>(msg =>
        {
            if (msg == "hello")
            {
                Sender.Tell("world");
            }
            else
            {
                Console.WriteLine($"Unknown message: {msg}");
            }
        });
    }
}

class Program
{
    static async Task Main(string[] args)
    {
        using var system = ActorSystem.Create("HelloSystem");

        var helloActor = system.ActorOf<HelloActor>("helloActor");

        // Ask 패턴으로 메시지 보내고 응답 받기
        var response = await helloActor.Ask<string>("hello", TimeSpan.FromSeconds(5));

        Console.WriteLine($"응답: {response}"); // "world"

        await system.Terminate();
    }
}

using Akka.Actor;
using Akka.Pattern;
using System;
using System.Threading.Tasks;

public class PipelinedActor : ReceiveActor
{
    public PipelinedActor()
    {
        Receive<string>(msg =>
        {
            if (msg == "hello")
            {
                Console.WriteLine($"[{Self.Path.Name}] 처리 시작: {msg}");

                // 무거운 작업 (예: DB 조회, 외부 API 등) 을 비동기로 시작
                var longTask = Task.Run(async () =>
                {
                    await Task.Delay(1000); // 1초 걸리는 비동기 작업
                    return "world (from async)";
                });

                // 작업 완료 시, 결과를 Sender에게 전달
                longTask.PipeTo(Sender, Self);
            }
            else
            {
                Sender.Tell("unknown");
            }
        });
    }

    public static Props Props() => Akka.Actor.Props.Create(() => new PipelinedActor());
}

class HelloActor : AbstractActor() {

    override fun createReceive(): Receive {
        return receiveBuilder()
            .matchEquals("hello") {
                sender.tell("world", self)
            }
            .matchAny {
                println("Unknown message: $it")
            }
            .build()
    }

    companion object {
        fun props(): Props = Props.create(HelloActor::class.java)
    }
}

fun main() {
    val system = ActorSystem.create("HelloSystem")
    val helloActor = system.actorOf(HelloActor.props(), "helloActor")

    val future = Patterns.ask(helloActor, "hello", 5000)
    val result = Await.result(future, Duration.create(5, TimeUnit.SECONDS)) as String

    println("응답: $result") // world 출력

    system.terminate()
}

import kotlinx.coroutines.channels.actor

// 메시지 정의
sealed class Message
data class Greet(val replyTo: CompletableDeferred<String>) : Message
object Unknown : Message

// 액터 함수
fun CoroutineScope.helloActor() = actor<Message> {
    for (msg in channel) {
        when (msg) {
            is Greet -> msg.replyTo.complete("world")
            else -> println("Unknown message received: $msg")
        }
    }
}

fun main() = runBlocking {
    val actor = helloActor()

    val response = CompletableDeferred<String>()
    actor.send(Greet(response))

    println("응답: ${response.await()}") // 출력: world

    actor.close()
}

// hello_actor.py
import ray

# Ray 초기화
ray.init()

# 액터 클래스 정의
@ray.remote
class HelloActor:
    def say(self, msg):
        if msg == "hello":
            return "world"
        else:
            return f"Unknown message: {msg}"

// main.py
import ray
from hello_actor import HelloActor

ray.init(ignore_reinit_error=True)  # 이미 실행 중일 경우 무시

# 액터 생성
actor = HelloActor.remote()

# 메시지 전송 및 응답 받기
response = ray.get(actor.say.remote("hello"))
print(f"응답: {response}")  # 출력: world

# 종료
ray.shutdown()

-module(hello_actor).
-export([start/0, loop/0]).

start() ->
    spawn(fun loop/0).

loop() ->
    receive
        {From, "hello"} ->
            From ! "world",
            loop();
        {From, Msg} ->
            From ! {error, "Unknown message: " ++ Msg},
            loop()
    end.


1> c(hello_actor). % 컴파일
2> Pid = hello_actor:start().  % 액터 시작
3> Pid ! {self(), "hello"}.    % 메시지 전송
4> flush().                    % 응답 확인

Shell output:
Shell got "world"

class HelloActorStreamTest {

    companion object {
        private val system = ActorSystem.create("TestSystem")
        private val materializer = ActorMaterializer.create(system)

        @JvmStatic
        @AfterClass
        fun teardown() {
            TestKit.shutdownActorSystem(system)
        }
    }

    @Test
    fun `should throttle and respond with world`() {
        object : TestKit(system) {
            init {
                val helloActor = system.actorOf(HelloActor.props())

                // Source.queue + throttle + ask pattern
                val (queue, done) = Source.queue<String>(10, OverflowStrategy.backpressure())
                    .throttle(3, JDuration.ofSeconds(1)) // 초당 3건
                    .mapAsync(1) { msg ->
                        akka.pattern.Patterns.ask(helloActor, msg, 1000).thenApply { it as String }
                    }
                    .toMat(Sink.foreach { response ->
                        println("응답 수신: $response")
                        expectMsgEquals("world")  // 테스트 검증
                    }, Keep.both())
                    .run(materializer)

                // 메시지 전송 (10건)
                for (i in 1..10) {
                    queue.offer("hello")
                }

                // 일부 응답 대기
                within(Duration.create(5, "seconds")) {
                    // 최소 3건은 들어왔는지 확인
                    for (i in 1..3) {
                        expectNoMessage()
                    }
                }
            }
        }
    }
}

                    +------------------+
                    |   Router (RoundRobinPool)   |
                    +------------------+
                    /        |        \
          HelloActor1  HelloActor2  HelloActor3

fun main() {
    val system = ActorSystem.create("RoundRobinSystem")

    // RoundRobinPool로 HelloActor 3개 구성
    val router = system.actorOf(
        RoundRobinPool(3).props(HelloActor.props()),
        "helloRouter"
    )

    println("=== 메시지 전송 시작 ===")
    for (i in 1..9) {
        val future = Patterns.ask(router, "hello $i", 1000)
        val result = Await.result(future, Duration.create(1, TimeUnit.SECONDS))
        println("응답 $i: $result")
    }

    system.terminate()
}

// Output
[helloRouter/$a] received: hello 1
응답 1: world
[helloRouter/$b] received: hello 2
응답 2: world
[helloRouter/$c] received: hello 3
응답 3: world
[helloRouter/$a] received: hello 4
응답 4: world
...

[Node1]  ↔  [Node2]  ↔  [Node3]
   │          │          │
 HelloActor HelloActor HelloActor