/**
 * 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.zookeeper;

import static org.junit.Assert.assertTrue;

import java.io.IOException;
import java.lang.reflect.Field;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Abortable;
import org.apache.hadoop.hbase.HBaseClassTestRule;
import org.apache.hadoop.hbase.HBaseZKTestingUtility;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.testclassification.MediumTests;
import org.apache.hadoop.hbase.testclassification.ZKTests;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.ClassRule;
import org.junit.Test;
import org.junit.experimental.categories.Category;

@Category({ ZKTests.class, MediumTests.class })
public class TestRecoverableZooKeeper {
  @ClassRule
  public static final HBaseClassTestRule CLASS_RULE =
      HBaseClassTestRule.forClass(TestRecoverableZooKeeper.class);

  private final static HBaseZKTestingUtility TEST_UTIL = new HBaseZKTestingUtility();

  private Abortable abortable = new Abortable() {
    @Override
    public void abort(String why, Throwable e) {
    }

    @Override
    public boolean isAborted() {
      return false;
    }
  };

  @BeforeClass
  public static void setUpBeforeClass() throws Exception {
    TEST_UTIL.startMiniZKCluster();
  }

  @AfterClass
  public static void tearDownAfterClass() throws Exception {
    TEST_UTIL.shutdownMiniZKCluster();
  }

  @Test
  public void testSetDataVersionMismatchInLoop() throws Exception {
    String znode = "/hbase/splitWAL/9af7cfc9b15910a0b3d714bf40a3248f";
    Configuration conf = TEST_UTIL.getConfiguration();
    ZKWatcher zkw = new ZKWatcher(conf, "testSetDataVersionMismatchInLoop",
        abortable, true);
    String ensemble = ZKConfig.getZKQuorumServersString(conf);
    RecoverableZooKeeper rzk = ZKUtil.connect(conf, ensemble, zkw);
    rzk.create(znode, new byte[0], Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    rzk.setData(znode, "OPENING".getBytes(), 0);
    Field zkField = RecoverableZooKeeper.class.getDeclaredField("zk");
    zkField.setAccessible(true);
    int timeout = conf.getInt(HConstants.ZK_SESSION_TIMEOUT, HConstants.DEFAULT_ZK_SESSION_TIMEOUT);
    ZookeeperStub zkStub = new ZookeeperStub(ensemble, timeout, zkw);
    zkStub.setThrowExceptionInNumOperations(1);
    zkField.set(rzk, zkStub);
    byte[] opened = "OPENED".getBytes();
    rzk.setData(znode, opened, 1);
    byte[] data = rzk.getData(znode, false, new Stat());
    assertTrue(Bytes.equals(opened, data));
  }

  static class ZookeeperStub extends ZooKeeper {
    private int throwExceptionInNumOperations;

    ZookeeperStub(String connectString, int sessionTimeout, Watcher watcher)
        throws IOException {
      super(connectString, sessionTimeout, watcher);
    }

    void setThrowExceptionInNumOperations(int throwExceptionInNumOperations) {
      this.throwExceptionInNumOperations = throwExceptionInNumOperations;
    }

    private void checkThrowKeeperException() throws KeeperException {
      if (throwExceptionInNumOperations == 1) {
        throwExceptionInNumOperations = 0;
        throw new KeeperException.ConnectionLossException();
      }
      if (throwExceptionInNumOperations > 0) {
        throwExceptionInNumOperations--;
      }
    }

    @Override
    public Stat setData(String path, byte[] data, int version) throws KeeperException,
        InterruptedException {
      Stat stat = super.setData(path, data, version);
      checkThrowKeeperException();
      return stat;
    }
  }
}
