/*
    * 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.omid.tso;
  
  import org.apache.omid.committable.CommitTable;
  import org.apache.omid.metrics.MetricsRegistry;
  import org.apache.omid.timestamp.storage.TimestampStorage;
  import org.mockito.InjectMocks;
  import org.mockito.Mock;
  import org.mockito.MockitoAnnotations;
  import org.mockito.invocation.InvocationOnMock;
  import org.mockito.stubbing.Answer;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.testng.annotations.BeforeMethod;
  import org.testng.annotations.Test;
  
  import java.util.concurrent.CountDownLatch;
  
  import static org.mockito.Matchers.any;
  import static org.mockito.Matchers.anyLong;
  import static org.mockito.Matchers.anyString;
  import static org.mockito.Mockito.atLeastOnce;
  import static org.mockito.Mockito.doAnswer;
  import static org.mockito.Mockito.verify;
  import static org.testng.Assert.assertEquals;
  import static org.testng.Assert.assertTrue;
  
  public class TestTimestampOracle {
  
      private static final Logger LOG = LoggerFactory.getLogger(TestTimestampOracle.class);
  
      @Mock
      private MetricsRegistry metrics;
      @Mock
      private Panicker panicker;
      @Mock
      private TimestampStorage timestampStorage;
      @Mock
      TSOServerConfig config;
  
      // Component under test
      @InjectMocks
      private TimestampOracleImpl timestampOracle;
  
      @BeforeMethod(alwaysRun = true, timeOut = 30_000)
      public void initMocksAndComponents() {
          MockitoAnnotations.initMocks(this);
      }
  
      @Test(timeOut = 60_000)
      public void testMonotonicTimestampGrowth() throws Exception {
  
          // Intialize component under test
          timestampOracle.initialize();
  
          long last = timestampOracle.next();
          for (int i = 0; i < (3 * TimestampOracleImpl.TIMESTAMP_BATCH); i++) {
              long current = timestampOracle.next();
              assertEquals(current, last + CommitTable.MAX_CHECKPOINTS_PER_TXN, "Not monotonic growth");
              last = current;
          }
          assertTrue(timestampOracle.getLast() == last);
          LOG.info("Last timestamp: {}", last);
      }
  
      @Test(timeOut = 10_000)
      public void testTimestampOraclePanicsWhenTheStorageHasProblems() throws Exception {
  
          // Intialize component under test
          timestampOracle.initialize();
  
          // Cause an exception when updating the max timestamp
          final CountDownLatch updateMaxTimestampMethodCalled = new CountDownLatch(1);
          doAnswer(new Answer() {
              @Override
              public Object answer(InvocationOnMock invocationOnMock) throws Throwable {
                  updateMaxTimestampMethodCalled.countDown();
                  throw new RuntimeException("Out of memory or something");
              }
          }).when(timestampStorage).updateMaxTimestamp(anyLong(), anyLong());
  
          // Make the previous exception to be thrown
          Thread allocThread = new Thread("AllocThread") {
             @Override
             public void run() {
                 while (true) {
                     timestampOracle.next();
                 }
             }
         };
         allocThread.start();
 
         updateMaxTimestampMethodCalled.await();
 
         // Verify that it has blown up
         verify(panicker, atLeastOnce()).panic(anyString(), any(Throwable.class));
     }
 
 }