/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.beam.runners.dataflow.worker;

import static junit.framework.TestCase.assertNotNull;
import static org.hamcrest.Matchers.equalTo;
import static org.junit.Assert.assertThat;
import static org.mockito.Mockito.mock;

import java.io.Closeable;
import java.io.IOException;
import org.apache.beam.runners.core.metrics.ExecutionStateSampler;
import org.apache.beam.runners.core.metrics.ExecutionStateTracker;
import org.apache.beam.runners.dataflow.options.DataflowPipelineDebugOptions;
import org.apache.beam.runners.dataflow.worker.DataflowExecutionContext.DataflowExecutionStateTracker;
import org.apache.beam.runners.dataflow.worker.TestOperationContext.TestDataflowExecutionState;
import org.apache.beam.runners.dataflow.worker.counters.Counter;
import org.apache.beam.runners.dataflow.worker.counters.CounterFactory;
import org.apache.beam.runners.dataflow.worker.counters.CounterFactory.CounterDistribution;
import org.apache.beam.runners.dataflow.worker.counters.CounterName;
import org.apache.beam.runners.dataflow.worker.counters.CounterSet;
import org.apache.beam.runners.dataflow.worker.counters.NameContext;
import org.apache.beam.runners.dataflow.worker.util.common.worker.ElementExecutionTracker;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.apache.beam.vendor.guava.v20_0.com.google.common.collect.Lists;
import org.joda.time.DateTimeUtils.MillisProvider;
import org.junit.Before;
import org.junit.Test;

/** Tests for {@link DataflowExecutionStateTrackerTest}. */
public class DataflowExecutionStateTrackerTest {

  private PipelineOptions options;
  private MillisProvider clock;
  private ExecutionStateSampler sampler;
  private CounterSet counterSet;

  @Before
  public void setUp() {
    options = PipelineOptionsFactory.create();
    clock = mock(MillisProvider.class);
    sampler = ExecutionStateSampler.newForTest(clock);
    counterSet = new CounterSet();
  }

  private final NameContext step1 =
      NameContext.create("stage", "originalStep1", "systemStep1", "userStep1");
  private final TestDataflowExecutionState step1Process =
      new TestDataflowExecutionState(step1, ExecutionStateTracker.PROCESS_STATE_NAME);

  @Test
  public void testReportsElementExecutionTime() throws IOException {
    enableTimePerElementExperiment();
    ExecutionStateTracker tracker = createTracker();

    try (Closeable c1 = tracker.activate(new Thread())) {
      try (Closeable c2 = tracker.enterState(step1Process)) {}
      sampler.doSampling(30);
      // Execution time split evenly between executions: IDLE, step1, IDLE
    }
    assertElementProcessingTimeCounter(step1, 10, 4);
  }

  /**
   * {@link DataflowExecutionStateTrackerTest} should take one last sample when a tracker is
   * deactivated.
   */
  @Test
  public void testTakesSampleOnDeactivate() throws IOException {
    enableTimePerElementExperiment();
    ExecutionStateTracker tracker = createTracker();

    try (Closeable c1 = tracker.activate(new Thread())) {
      try (Closeable c2 = tracker.enterState(step1Process)) {
        sampler.doSampling(100);
        assertThat(step1Process.getTotalMillis(), equalTo(100L));
      }
    }

    sampler.doSampling(100);
    assertThat(step1Process.getTotalMillis(), equalTo(100L));
  }

  private void enableTimePerElementExperiment() {
    options
        .as(DataflowPipelineDebugOptions.class)
        .setExperiments(
            Lists.newArrayList(DataflowElementExecutionTracker.TIME_PER_ELEMENT_EXPERIMENT));
  }

  private void assertElementProcessingTimeCounter(NameContext step, int millis, int bucketOffset) {
    CounterName counterName = ElementExecutionTracker.COUNTER_NAME.withOriginalName(step);
    Counter<?, CounterDistribution> counter =
        (Counter<?, CounterFactory.CounterDistribution>) counterSet.getExistingCounter(counterName);
    assertNotNull(counter);

    CounterFactory.CounterDistribution distribution = counter.getAggregate();
    assertThat(
        distribution,
        equalTo(
            CounterFactory.CounterDistribution.builder()
                .minMax(millis, millis)
                .count(1)
                .sum(millis)
                .sumOfSquares(millis * millis)
                .buckets(bucketOffset, Lists.newArrayList(1L))
                .build()));
  }

  private ExecutionStateTracker createTracker() {
    return new DataflowExecutionStateTracker(
        sampler,
        new TestDataflowExecutionState(NameContext.forStage("test-stage"), "other"),
        counterSet,
        options,
        "test-work-item-id");
  }
}