/**
    * 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.fs;
  
  import java.lang.reflect.Field;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FSDataOutputStream;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.MiniHBaseCluster;
  import org.apache.hadoop.hbase.testclassification.LargeTests;
  import org.apache.hadoop.hbase.testclassification.MiscTests;
  import org.apache.hadoop.hbase.wal.DefaultWALProvider;
  import org.apache.hadoop.hdfs.DFSClient;
  import org.apache.hadoop.hdfs.DistributedFileSystem;
  import org.apache.hadoop.hdfs.MiniDFSCluster;
  import org.apache.hadoop.hdfs.protocol.ClientProtocol;
  import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
  import org.junit.After;
  import org.junit.Assert;
  import org.junit.Before;
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  import org.junit.rules.TestName;
  
  /**
   * Tests for the hdfs fix from HBASE-6435.
   *
   * Please don't add new subtest which involves starting / stopping MiniDFSCluster in this class.
   * When stopping MiniDFSCluster, shutdown hooks would be cleared in hadoop's ShutdownHookManager
   *   in hadoop 3.
   * This leads to 'Failed suppression of fs shutdown hook' error in region server.
   */
  @Category({MiscTests.class, LargeTests.class})
  public class TestBlockReorderBlockLocation {
  
    private Configuration conf;
    private MiniDFSCluster cluster;
    private HBaseTestingUtility htu;
    private DistributedFileSystem dfs;
    private static final String host1 = "host1";
    private static final String host2 = "host2";
    private static final String host3 = "host3";
  
    @Rule
    public TestName name = new TestName();
  
    @Before
    public void setUp() throws Exception {
      htu = new HBaseTestingUtility();
      htu.getConfiguration().setInt("dfs.blocksize", 1024);// For the test with multiple blocks
      htu.getConfiguration().setInt("dfs.replication", 3);
      htu.startMiniDFSCluster(3,
          new String[]{"/r1", "/r2", "/r3"}, new String[]{host1, host2, host3});
  
      conf = htu.getConfiguration();
      cluster = htu.getDFSCluster();
      dfs = (DistributedFileSystem) FileSystem.get(conf);
    }
  
    @After
    public void tearDownAfterClass() throws Exception {
      htu.shutdownMiniCluster();
    }
  
  
    private static ClientProtocol getNamenode(DFSClient dfsc) throws Exception {
      Field nf = DFSClient.class.getDeclaredField("namenode");
      nf.setAccessible(true);
      return (ClientProtocol) nf.get(dfsc);
    }
  
    /**
     * Test that the reorder algo works as we expect.
     */
    @Test
    public void testBlockLocation() throws Exception {
      // We need to start HBase to get  HConstants.HBASE_DIR set in conf
      htu.startMiniZKCluster();
      MiniHBaseCluster hbm = htu.startMiniHBaseCluster(1, 1);
      conf = hbm.getConfiguration();
 
 
     // The "/" is mandatory, without it we've got a null pointer exception on the namenode
     final String fileName = "/helloWorld";
     Path p = new Path(fileName);
 
     final int repCount = 3;
     Assert.assertTrue((short) cluster.getDataNodes().size() >= repCount);
 
     // Let's write the file
     FSDataOutputStream fop = dfs.create(p, (short) repCount);
     final double toWrite = 875.5613;
     fop.writeDouble(toWrite);
     fop.close();
 
     for (int i=0; i<10; i++){
       // The interceptor is not set in this test, so we get the raw list at this point
       LocatedBlocks l;
       final long max = System.currentTimeMillis() + 10000;
       do {
         l = getNamenode(dfs.getClient()).getBlockLocations(fileName, 0, 1);
         Assert.assertNotNull(l.getLocatedBlocks());
         Assert.assertEquals(1, l.getLocatedBlocks().size());
         Assert.assertTrue("Expecting " + repCount + " , got " + l.get(0).getLocations().length,
             System.currentTimeMillis() < max);
       } while (l.get(0).getLocations().length != repCount);
 
       // Should be filtered, the name is different => The order won't change
       Object[] originalList = l.getLocatedBlocks().toArray();
       HFileSystem.ReorderWALBlocks lrb = new HFileSystem.ReorderWALBlocks();
       lrb.reorderBlocks(conf, l, fileName);
       Assert.assertArrayEquals(originalList, l.getLocatedBlocks().toArray());
 
       // Should be reordered, as we pretend to be a file name with a compliant stuff
       Assert.assertNotNull(conf.get(HConstants.HBASE_DIR));
       Assert.assertFalse(conf.get(HConstants.HBASE_DIR).isEmpty());
       String pseudoLogFile = conf.get(HConstants.HBASE_DIR) + "/" +
           HConstants.HREGION_LOGDIR_NAME + "/" + host1 + ",6977,6576" + "/mylogfile";
 
       // Check that it will be possible to extract a ServerName from our construction
       Assert.assertNotNull("log= " + pseudoLogFile,
         DefaultWALProvider.getServerNameFromWALDirectoryName(dfs.getConf(), pseudoLogFile));
 
       // And check we're doing the right reorder.
       lrb.reorderBlocks(conf, l, pseudoLogFile);
       Assert.assertEquals(host1, l.get(0).getLocations()[2].getHostName());
 
       // Check again, it should remain the same.
       lrb.reorderBlocks(conf, l, pseudoLogFile);
       Assert.assertEquals(host1, l.get(0).getLocations()[2].getHostName());
     }
   }
 }