/**
    * 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.hadoop.hbase.regionserver.compactions;
  
  import static org.junit.Assert.assertEquals;
  
  import com.google.common.collect.Lists;
  import java.util.Date;
  import java.util.List;
  import java.util.TimeZone;
  import org.apache.hadoop.hbase.testclassification.RegionServerTests;
  import org.apache.hadoop.hbase.testclassification.SmallTests;
  import org.apache.hadoop.hbase.util.EnvironmentEdge;
  import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  @Category({RegionServerTests.class, SmallTests.class})
  public class TestCurrentHourProvider {
  
    private static final List<String> ZONE_IDS = Lists.newArrayList("UTC", "US/Pacific", "Etc/GMT+8");
  
    /**
     * In timezone GMT+08:00, the unix time of 2020-08-20 11:52:41 is 1597895561000 and the unix time
     * of 2020-08-20 15:04:00 is 1597907081000, by calculating the delta time to get expected time in
     * current timezone, then we can get special hour no matter which timezone it runs.
     * <p/>
     * In addition, we should consider the Daylight Saving Time. If in DaylightTime, we need reduce
     * one hour.
     */
    @Test
    public void testWithEnvironmentEdge() {
      // test for all available zoneID
      for (String zoneID : ZONE_IDS) {
        TimeZone timezone = TimeZone.getTimeZone(zoneID);
        TimeZone.setDefault(timezone);
  
        // set a time represent hour 11
        long deltaFor11 = TimeZone.getDefault().getRawOffset() - 28800000;
        final long timeFor11 = 1597895561000L - deltaFor11;
        EnvironmentEdgeManager.injectEdge(new EnvironmentEdge() {
          @Override
          public long currentTime() {
            return timeFor11;
          }
        });
        CurrentHourProvider.advanceTick();
        int hour11 = CurrentHourProvider.getCurrentHour();
        if (TimeZone.getDefault().inDaylightTime(new Date(timeFor11))) {
          hour11 = CurrentHourProvider.getCurrentHour() - 1;
        }
        assertEquals(11, hour11);
  
        // set a time represent hour 15
        long deltaFor15 = TimeZone.getDefault().getRawOffset() - 28800000;
        final long timeFor15 = 1597907081000L - deltaFor15;
        EnvironmentEdgeManager.injectEdge(new EnvironmentEdge() {
          @Override
          public long currentTime() {
            return timeFor15;
          }
        });
        CurrentHourProvider.advanceTick();
        int hour15 = CurrentHourProvider.getCurrentHour();
        if (TimeZone.getDefault().inDaylightTime(new Date(timeFor15))) {
          hour15 = CurrentHourProvider.getCurrentHour() - 1;
        }
        assertEquals(15, hour15);
      }
    }
  }