/*-
 * -\-\-
 * Helios Services
 * --
 * Copyright (C) 2016 Spotify AB
 * --
 * 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 com.spotify.helios.agent;

import static com.spotify.helios.agent.DockerHealthChecker.FAILURE_HIGH_WATERMARK;
import static com.spotify.helios.agent.DockerHealthChecker.FAILURE_LOW_WATERMARK;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.mockito.Mockito.when;

import com.spotify.helios.servicescommon.statistics.MeterRates;
import com.spotify.helios.servicescommon.statistics.SupervisorMetrics;
import java.util.concurrent.TimeUnit;
import org.junit.Before;
import org.junit.Test;
import org.mockito.Mockito;

public class DockerHealthCheckerTest {
  private static final MeterRates OK_RATE = makeMeter(FAILURE_LOW_WATERMARK - .01);
  private static final MeterRates BETWEEN_RATE = makeMeter(FAILURE_HIGH_WATERMARK - .01);
  private static final MeterRates RUN_RATE = makeMeter(1);
  private static final MeterRates ZERO_RATE = makeMeter(0);
  private static final MeterRates BAD_RATE = makeMeter(FAILURE_HIGH_WATERMARK + .01);

  private SupervisorMetrics metrics;
  private DockerHealthChecker checker;

  private static MeterRates makeMeter(double percentage) {
    final int value = (int) (percentage * 100);
    return new MeterRates(value, value, value);
  }

  @Before
  public void setUp() throws Exception {
    metrics = Mockito.mock(SupervisorMetrics.class);
    checker = new DockerHealthChecker(metrics, TimeUnit.SECONDS, 1);
  }

  @Test
  public void testTimeouts() throws Exception {
    when(metrics.getDockerTimeoutRates()).thenReturn(BAD_RATE); // start out as many timeouts
    when(metrics.getContainersThrewExceptionRates()).thenReturn(ZERO_RATE);
    when(metrics.getSupervisorRunRates()).thenReturn(RUN_RATE);

    checker.start();
    assertFalse(checker.check().isHealthy());

    when(metrics.getDockerTimeoutRates()).thenReturn(BETWEEN_RATE);
    Thread.sleep(2);
    assertFalse(checker.check().isHealthy());

    when(metrics.getDockerTimeoutRates()).thenReturn(OK_RATE);
    assertTrue(checker.check().isHealthy());
  }

  @Test
  public void testExceptions() throws Exception {
    when(metrics.getDockerTimeoutRates()).thenReturn(ZERO_RATE);
    when(metrics.getContainersThrewExceptionRates()).thenReturn(BAD_RATE);
    when(metrics.getSupervisorRunRates()).thenReturn(RUN_RATE);

    checker.start();

    assertFalse(checker.check().isHealthy());

    when(metrics.getContainersThrewExceptionRates()).thenReturn(BETWEEN_RATE);
    assertFalse(checker.check().isHealthy());

    when(metrics.getContainersThrewExceptionRates()).thenReturn(OK_RATE);
    assertTrue(checker.check().isHealthy());
  }

  @Test
  public void testBoth() throws Exception {
    when(metrics.getDockerTimeoutRates()).thenReturn(ZERO_RATE);
    when(metrics.getContainersThrewExceptionRates()).thenReturn(BAD_RATE);
    when(metrics.getSupervisorRunRates()).thenReturn(RUN_RATE);

    checker.start();

    assertFalse(checker.check().isHealthy());

    when(metrics.getContainersThrewExceptionRates()).thenReturn(BETWEEN_RATE);
    assertFalse(checker.check().isHealthy());

    when(metrics.getContainersThrewExceptionRates()).thenReturn(OK_RATE);
    when(metrics.getDockerTimeoutRates()).thenReturn(BETWEEN_RATE); // between maintains unhealthy
    assertFalse(checker.check().isHealthy());

    when(metrics.getDockerTimeoutRates()).thenReturn(OK_RATE);
    assertTrue(checker.check().isHealthy());
  }
}