/*
 * Copyright (C) 2018 Lightbend Inc. <https://www.lightbend.com>
 */

package akka.actor.dispatch

import language.postfixOps

import java.util.concurrent.{ CountDownLatch, TimeUnit }
import java.util.concurrent.atomic.{ AtomicBoolean }
import akka.testkit.{ AkkaSpec }
import akka.actor.{ Props, Actor }
import scala.concurrent.Await
import scala.concurrent.duration._
import akka.testkit.DefaultTimeout
import akka.pattern.ask

object DispatcherActorSpec {
  val config = """
    test-dispatcher {
    }
    test-throughput-dispatcher {
      throughput = 101
      executor = "thread-pool-executor"
      thread-pool-executor {
        fixed-pool-size = 1
      }
    }
    test-throughput-deadline-dispatcher {
      throughput = 2
      throughput-deadline-time = 100 milliseconds
      executor = "thread-pool-executor"
      thread-pool-executor {
        fixed-pool-size = 1
      }
    }

    """
  class TestActor extends Actor {
    def receive = {
      case "Hello"   ⇒ sender() ! "World"
      case "Failure" ⇒ throw new RuntimeException("Expected exception; to test fault-tolerance")
    }
  }

  object OneWayTestActor {
    val oneWay = new CountDownLatch(1)
  }
  class OneWayTestActor extends Actor {
    def receive = {
      case "OneWay" ⇒ OneWayTestActor.oneWay.countDown()
    }
  }
}

class DispatcherActorSpec extends AkkaSpec(DispatcherActorSpec.config) with DefaultTimeout {
  import DispatcherActorSpec._

  private val unit = TimeUnit.MILLISECONDS

  "A Dispatcher and an Actor" must {

    "support tell" in {
      val actor = system.actorOf(Props[OneWayTestActor].withDispatcher("test-dispatcher"))
      val result = actor ! "OneWay"
      assert(OneWayTestActor.oneWay.await(1, TimeUnit.SECONDS))
      system.stop(actor)
    }

    "support ask/reply" in {
      val actor = system.actorOf(Props[TestActor].withDispatcher("test-dispatcher"))
      assert("World" === Await.result(actor ? "Hello", timeout.duration))
      system.stop(actor)
    }

    "respect the throughput setting" in {
      val throughputDispatcher = "test-throughput-dispatcher"

      val works = new AtomicBoolean(true)
      val latch = new CountDownLatch(100)
      val start = new CountDownLatch(1)
      val fastOne = system.actorOf(
        Props(new Actor { def receive = { case "sabotage" ⇒ works.set(false) } })
          .withDispatcher(throughputDispatcher))

      val slowOne = system.actorOf(
        Props(new Actor {
          def receive = {
            case "hogexecutor" ⇒ { sender() ! "OK"; start.await }
            case "ping"        ⇒ if (works.get) latch.countDown()
          }
        }).withDispatcher(throughputDispatcher))

      assert(Await.result(slowOne ? "hogexecutor", timeout.duration) === "OK")
      (1 to 100) foreach { _ ⇒ slowOne ! "ping" }
      fastOne ! "sabotage"
      start.countDown()
      latch.await(10, TimeUnit.SECONDS)
      system.stop(fastOne)
      system.stop(slowOne)
      assert(latch.getCount() === 0L)
    }

    "respect throughput deadline" in {
      val deadline = 100 millis
      val throughputDispatcher = "test-throughput-deadline-dispatcher"

      val works = new AtomicBoolean(true)
      val latch = new CountDownLatch(1)
      val start = new CountDownLatch(1)
      val ready = new CountDownLatch(1)

      val fastOne = system.actorOf(
        Props(new Actor {
          def receive = {
            case "ping" ⇒ if (works.get) latch.countDown(); context.stop(self)
          }
        }).withDispatcher(throughputDispatcher))

      val slowOne = system.actorOf(
        Props(new Actor {
          def receive = {
            case "hogexecutor" ⇒ { ready.countDown(); start.await }
            case "ping"        ⇒ { works.set(false); context.stop(self) }
          }
        }).withDispatcher(throughputDispatcher))

      slowOne ! "hogexecutor"
      slowOne ! "ping"
      fastOne ! "ping"
      assert(ready.await(2, TimeUnit.SECONDS) === true)
      Thread.sleep(deadline.toMillis + 10) // wait just a bit more than the deadline
      start.countDown()
      assert(latch.await(2, TimeUnit.SECONDS) === true)
    }
  }
}
