/*
 * =========================================================================================
 * Copyright © 2013 the kamon project <http://kamon.io/>
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the
 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific language governing permissions
 * and limitations under the License.
 * =========================================================================================
 */

package akka.instrumentation

import org.aspectj.lang.annotation.{ AfterReturning, Pointcut, Aspect }
import akka.event.Logging.Warning
import scala.compat.Platform.EOL
import akka.actor.ActorRefProvider
import akka.pattern.{ AskTimeoutException, PromiseActorRef }
import kamon.trace.Trace
import kamon.Kamon

@Aspect
class AskPatternTracing {

  class StackTraceCaptureException extends Throwable

  @Pointcut(value = "execution(* akka.pattern.PromiseActorRef$.apply(..)) && args(provider, *, *)", argNames = "provider")
  def promiseActorRefApply(provider: ActorRefProvider): Unit = {}

  @AfterReturning(pointcut = "promiseActorRefApply(provider)", returning = "promiseActor")
  def hookAskTimeoutWarning(provider: ActorRefProvider, promiseActor: PromiseActorRef): Unit = {
    val system = promiseActor.provider.guardian.underlying.system
    val traceExtension = Kamon(Trace)(system)

    if (traceExtension.enableAskPatternTracing) {
      val future = promiseActor.result.future
      implicit val ec = system.dispatcher
      val stack = new StackTraceCaptureException

      future onFailure {
        case timeout: AskTimeoutException ⇒
          val stackString = stack.getStackTrace.drop(3).mkString("", EOL, EOL)

          system.eventStream.publish(Warning("AskPatternTracing", classOf[AskPatternTracing],
            "Timeout triggered for ask pattern registered at: " + stackString))
      }
    }
  }
}