import akka.actor.{ActorRef, ActorSystem, Props, Actor, Inbox}
import scala.concurrent.duration._

case object Greet
case class WhoToGreet(who: String)
case class Greeting(message: String)

class Greeter extends Actor {
  var greeting = ""

  def receive = {
    case WhoToGreet(who) => greeting = s"hello, $who"
    case Greet           => sender ! Greeting(greeting)
  }
}

class GreetPrinter extends Actor {
  def receive = {
    case Greeting(message) => println(message)
  }
}

object HelloWorld extends App {
  val system = ActorSystem("HelloWorld")
  val greeter = system.actorOf(Props[Greeter], "greeter")
  val inbox = Inbox.create(system)

  greeter.tell(WhoToGreet("vixlur"), ActorRef.noSender)
  inbox.send(greeter, Greet)

  val Greeting(message) = inbox.receive(5.seconds)
  println(s"Greeting: $message")

  val greetPrinter = system.actorOf(Props[GreetPrinter])
  system.scheduler.schedule(0.seconds, 1.second, greeter, Greet)(system.dispatcher, greetPrinter)
}