package nova.monadic_sfx.actors

import akka.actor.typed._
import akka.actor.typed.scaladsl._

object Counter {
  sealed trait Command
  case object Increment extends Command
  final case class GetValue(replyTo: ActorRef[Value]) extends Command
  final case class Value(n: Int)
  final case object Stop extends Command

  def apply(): Behavior[Command] = {
    Behaviors.setup(context => new Counter(context))
  }
}

class Counter(context: ActorContext[Counter.Command])
    extends AbstractBehavior[Counter.Command](context) {
  import Counter._

  private var n = 0

  override def onMessage(msg: Command): Behavior[Counter.Command] = {
    msg match {
      case Increment =>
        n += 1
        context.log.debug("Incremented counter to [{}]", n)
        this
      case GetValue(replyTo) =>
        replyTo ! Value(n)
        this
      case Stop =>
        context.log.info("Recieved shutdown counter actor")
        Behaviors.stopped
    }
  }

  override def onSignal: PartialFunction[Signal, Behavior[Counter.Command]] = {
    case _: Terminated =>
      context.log.info("Recieved shutdown counter actor terminated")
      this
    case PostStop =>
      context.log.info("Recieved shutdown counter actor poststop")
      this
  }

}