/*
 * 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.accumulo.server.util.time;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import org.junit.Test;

public class BaseRelativeTimeTest {

  static class BogusTime implements ProvidesTime {
    public long value = 0;

    @Override
    public long currentTime() {
      return value;
    }
  }

  @Test
  public void testMatchesTime() {
    BogusTime bt = new BogusTime();
    BogusTime now = new BogusTime();
    now.value = bt.value = System.currentTimeMillis();

    BaseRelativeTime brt = new BaseRelativeTime(now);
    assertEquals(brt.currentTime(), now.value);
    brt.updateTime(now.value);
    assertEquals(brt.currentTime(), now.value);
  }

  @Test
  public void testFutureTime() {
    BogusTime advice = new BogusTime();
    BogusTime local = new BogusTime();
    local.value = advice.value = System.currentTimeMillis();
    // Ten seconds into the future
    advice.value += 10000;

    BaseRelativeTime brt = new BaseRelativeTime(local);
    assertEquals(brt.currentTime(), local.value);
    brt.updateTime(advice.value);
    long once = brt.currentTime();
    assertTrue(once < advice.value);
    assertTrue(once > local.value);

    for (int i = 0; i < 100; i++) {
      brt.updateTime(advice.value);
    }
    long many = brt.currentTime();
    assertTrue(many > once);
    assertTrue("after much advice, relative time is still closer to local time", (advice.value - many) < (once - local.value));
  }

  @Test
  public void testPastTime() {
    BogusTime advice = new BogusTime();
    BogusTime local = new BogusTime();
    local.value = advice.value = System.currentTimeMillis();
    // Ten seconds into the past
    advice.value -= 10000;

    BaseRelativeTime brt = new BaseRelativeTime(local);
    brt.updateTime(advice.value);
    long once = brt.currentTime();
    assertTrue(once < local.value);
    brt.updateTime(advice.value);
    long twice = brt.currentTime();
    assertTrue("Time cannot go backwards", once <= twice);
    brt.updateTime(advice.value - 10000);
    assertTrue("Time cannot go backwards", once <= twice);
  }

}