/*
 * =========================================================================================
 * 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 kamon.spray

import _root_.spray.httpx.RequestBuilding
import akka.testkit.{ TestKitBase, TestProbe }
import akka.actor.ActorSystem
import org.scalatest.{ Matchers, WordSpecLike }
import kamon.Kamon
import org.scalatest.concurrent.{ PatienceConfiguration, ScalaFutures }
import spray.http.HttpHeaders.RawHeader
import spray.http.{ HttpResponse, HttpRequest }
import kamon.metric.{ TraceMetrics, Metrics }
import kamon.metric.Subscriptions.TickMetricSnapshot
import com.typesafe.config.ConfigFactory
import kamon.metric.TraceMetrics.ElapsedTime
import kamon.metric.instrument.Histogram

class SprayServerTracingSpec extends TestKitBase with WordSpecLike with Matchers with RequestBuilding
    with ScalaFutures with PatienceConfiguration with TestServer {

  implicit lazy val system: ActorSystem = ActorSystem("spray-server-tracing-spec", ConfigFactory.parseString(
    """
      |akka {
      |  loglevel = ERROR
      |}
      |
      |kamon {
      |  metrics {
      |    tick-interval = 2 seconds
      |
      |    filters = [
      |      {
      |        trace {
      |          includes = [ "*" ]
      |          excludes = []
      |        }
      |      }
      |    ]
      |  }
      |}
    """.stripMargin))

  "the spray server request tracing instrumentation" should {
    "include the trace-token header in responses when the automatic-trace-token-propagation is enabled" in {
      enableAutomaticTraceTokenPropagation()

      val (connection, server) = buildClientConnectionAndServer
      val client = TestProbe()

      client.send(connection, Get("/").withHeaders(RawHeader(Kamon(Spray).traceTokenHeaderName, "propagation-enabled")))
      server.expectMsgType[HttpRequest]
      server.reply(HttpResponse(entity = "ok"))
      val response = client.expectMsgType[HttpResponse]

      response.headers should contain(RawHeader(Kamon(Spray).traceTokenHeaderName, "propagation-enabled"))
    }

    "reply back with an automatically assigned trace token if none was provided with the request and automatic-trace-token-propagation is enabled" in {
      enableAutomaticTraceTokenPropagation()

      val (connection, server) = buildClientConnectionAndServer
      val client = TestProbe()

      client.send(connection, Get("/"))
      server.expectMsgType[HttpRequest]
      server.reply(HttpResponse(entity = "ok"))
      val response = client.expectMsgType[HttpResponse]

      response.headers.filter(_.name == Kamon(Spray).traceTokenHeaderName).size should be(1)

    }

    "not include the trace-token header in responses when the automatic-trace-token-propagation is disabled" in {
      disableAutomaticTraceTokenPropagation()

      val (connection, server) = buildClientConnectionAndServer
      val client = TestProbe()

      client.send(connection, Get("/").withHeaders(RawHeader(Kamon(Spray).traceTokenHeaderName, "propagation-disabled")))
      server.expectMsgType[HttpRequest]
      server.reply(HttpResponse(entity = "ok"))
      val response = client.expectMsgType[HttpResponse]

      response.headers should not contain (RawHeader(Kamon(Spray).traceTokenHeaderName, "propagation-disabled"))
    }
  }

  def enableAutomaticTraceTokenPropagation(): Unit = setIncludeTraceToken(true)
  def disableAutomaticTraceTokenPropagation(): Unit = setIncludeTraceToken(false)

  def setIncludeTraceToken(include: Boolean): Unit = {
    val target = Kamon(Spray)(system)
    val field = target.getClass.getDeclaredField("includeTraceToken")
    field.setAccessible(true)
    field.set(target, include)
  }

}