/*
 * =========================================================================================
 * 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.metric

import com.typesafe.config.ConfigFactory
import kamon.Kamon
import kamon.metric.instrument.Histogram.MutableRecord
import kamon.testkit.BaseKamonSpec
import kamon.util.MilliTimestamp
import akka.testkit.ImplicitSender
import scala.concurrent.duration._
import kamon.metric.SubscriptionsDispatcher.TickMetricSnapshot

class TickMetricSnapshotBufferSpec extends BaseKamonSpec("trace-metrics-spec") with ImplicitSender {

  "the TickMetricSnapshotBuffer" should {
    "merge TickMetricSnapshots received until the flush timeout is reached and fix the from/to fields" in new SnapshotFixtures {
      val buffer = system.actorOf(TickMetricSnapshotBuffer.props(3 seconds, testActor))

      buffer ! firstEmpty
      buffer ! secondEmpty
      buffer ! thirdEmpty

      within(2 seconds)(expectNoMsg())
      val mergedSnapshot = expectMsgType[TickMetricSnapshot]

      mergedSnapshot.from.millis should equal(1000)
      mergedSnapshot.to.millis should equal(4000)
      mergedSnapshot.metrics should be('empty)
    }

    "merge empty and non-empty snapshots" in new SnapshotFixtures {
      val buffer = system.actorOf(TickMetricSnapshotBuffer.props(3 seconds, testActor))

      buffer ! firstNonEmpty
      buffer ! secondNonEmpty
      buffer ! thirdEmpty

      within(2 seconds)(expectNoMsg())
      val mergedSnapshot = expectMsgType[TickMetricSnapshot]

      mergedSnapshot.from.millis should equal(1000)
      mergedSnapshot.to.millis should equal(4000)
      mergedSnapshot.metrics should not be ('empty)

      val testMetricSnapshot = mergedSnapshot.metrics(testTraceIdentity).histogram("elapsed-time").get
      testMetricSnapshot.min should equal(10)
      testMetricSnapshot.max should equal(300)
      testMetricSnapshot.numberOfMeasurements should equal(6)
      testMetricSnapshot.recordsIterator.toStream should contain allOf (
        MutableRecord(10, 3),
        MutableRecord(20, 1),
        MutableRecord(30, 1),
        MutableRecord(300, 1))

    }
  }

  trait SnapshotFixtures {
    val collectionContext = Kamon.metrics.buildDefaultCollectionContext
    val testTraceIdentity = Entity("buffer-spec-test-trace", "trace")
    val traceRecorder = Kamon.metrics.entity(TraceMetrics, "buffer-spec-test-trace")

    val firstEmpty = TickMetricSnapshot(new MilliTimestamp(1000), new MilliTimestamp(2000), Map.empty)
    val secondEmpty = TickMetricSnapshot(new MilliTimestamp(2000), new MilliTimestamp(3000), Map.empty)
    val thirdEmpty = TickMetricSnapshot(new MilliTimestamp(3000), new MilliTimestamp(4000), Map.empty)

    traceRecorder.elapsedTime.record(10L)
    traceRecorder.elapsedTime.record(20L)
    traceRecorder.elapsedTime.record(30L)
    val firstNonEmpty = TickMetricSnapshot(new MilliTimestamp(1000), new MilliTimestamp(2000), Map(
      (testTraceIdentity -> traceRecorder.collect(collectionContext))))

    traceRecorder.elapsedTime.record(10L)
    traceRecorder.elapsedTime.record(10L)
    traceRecorder.elapsedTime.record(300L)
    val secondNonEmpty = TickMetricSnapshot(new MilliTimestamp(1000), new MilliTimestamp(2000), Map(
      (testTraceIdentity -> traceRecorder.collect(collectionContext))))
  }
}