/**
 * 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.mapred;

import java.io.DataOutputStream;
import java.io.IOException;

import junit.framework.TestCase;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.DFSTestUtil;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.io.Text;

public class TestFileInputFormat extends TestCase {

  Configuration conf = new Configuration();
  MiniDFSCluster dfs = null;

  private MiniDFSCluster newDFSCluster(JobConf conf) throws Exception {
    return new MiniDFSCluster(conf, 4, true,
                         new String[]{"/rack0", "/rack0",
                                      "/rack1", "/rack1"},
                         new String[]{"host0", "host1",
                                      "host2", "host3"});
  }

  public void testLocality() throws Exception {
    JobConf job = new JobConf(conf);
    dfs = newDFSCluster(job);
    FileSystem fs = dfs.getFileSystem();
    System.out.println("FileSystem " + fs.getUri());

    Path inputDir = new Path("/foo/");
    String fileName = "part-0000";
    createInputs(fs, inputDir, fileName);

    // split it using a file input format
    TextInputFormat.addInputPath(job, inputDir);
    TextInputFormat inFormat = new TextInputFormat();
    inFormat.configure(job);
    InputSplit[] splits = inFormat.getSplits(job, 1);
    FileStatus fileStatus = fs.getFileStatus(new Path(inputDir, fileName));
    BlockLocation[] locations =
      fs.getFileBlockLocations(fileStatus, 0, fileStatus.getLen());
    System.out.println("Made splits");

    // make sure that each split is a block and the locations match
    for(int i=0; i < splits.length; ++i) {
      FileSplit fileSplit = (FileSplit) splits[i];
      System.out.println("File split: " + fileSplit);
      for (String h: fileSplit.getLocations()) {
        System.out.println("Location: " + h);
      }
      System.out.println("Block: " + locations[i]);
      assertEquals(locations[i].getOffset(), fileSplit.getStart());
      assertEquals(locations[i].getLength(), fileSplit.getLength());
      String[] blockLocs = locations[i].getHosts();
      String[] splitLocs = fileSplit.getLocations();
      assertEquals(2, blockLocs.length);
      assertEquals(2, splitLocs.length);
      assertTrue((blockLocs[0].equals(splitLocs[0]) &&
                  blockLocs[1].equals(splitLocs[1])) ||
                 (blockLocs[1].equals(splitLocs[0]) &&
                  blockLocs[0].equals(splitLocs[1])));
    }

    assertEquals("Expected value of " + FileInputFormat.NUM_INPUT_FILES,
                 1, job.getLong(FileInputFormat.NUM_INPUT_FILES, 0));
  }

  private void createInputs(FileSystem fs, Path inDir, String fileName)
  throws IOException {
    // create a multi-block file on hdfs
    DataOutputStream out = fs.create(new Path(inDir, fileName), true, 4096,
                                     (short) 2, 512, null);
    for(int i=0; i < 1000; ++i) {
      out.writeChars("Hello\n");
    }
    out.close();
    System.out.println("Wrote file");
  }

  public void testNumInputs() throws Exception {
    JobConf job = new JobConf(conf);
    dfs = newDFSCluster(job);
    FileSystem fs = dfs.getFileSystem();
    System.out.println("FileSystem " + fs.getUri());

    Path inputDir = new Path("/foo/");
    final int numFiles = 10;
    String fileNameBase = "part-0000";
    for (int i=0; i < numFiles; ++i) {
      createInputs(fs, inputDir, fileNameBase + String.valueOf(i));
    }
    createInputs(fs, inputDir, "_meta");
    createInputs(fs, inputDir, "_temp");

    // split it using a file input format
    TextInputFormat.addInputPath(job, inputDir);
    TextInputFormat inFormat = new TextInputFormat();
    inFormat.configure(job);
    InputSplit[] splits = inFormat.getSplits(job, 1);

    assertEquals("Expected value of " + FileInputFormat.NUM_INPUT_FILES,
                 numFiles, job.getLong(FileInputFormat.NUM_INPUT_FILES, 0));
  }
  
  final Path root = new Path("/TestFileInputFormat");
  final Path file1 = new Path(root, "file1");
  final Path dir1 = new Path(root, "dir1");
  final Path file2 = new Path(dir1, "file2");

  static final int BLOCKSIZE = 1024;
  static final byte[] databuf = new byte[BLOCKSIZE];

  private static final String rack1[] = new String[] {
    "/r1"
  };
  private static final String hosts1[] = new String[] {
    "host1.rack1.com"
  };
  
  private class DummyFileInputFormat extends FileInputFormat<Text, Text> {
    @Override
    public RecordReader<Text, Text> getRecordReader(InputSplit split,
        JobConf job, Reporter reporter) throws IOException {
      return null;
    }
  }

  public void testMultiLevelInput() throws IOException {
    JobConf job = new JobConf(conf);

    job.setBoolean("dfs.replication.considerLoad", false);
    dfs = new MiniDFSCluster(job, 1, true, rack1, hosts1);
    dfs.waitActive();

    String namenode = (dfs.getFileSystem()).getUri().getHost() + ":" +
                      (dfs.getFileSystem()).getUri().getPort();

    FileSystem fileSys = dfs.getFileSystem();
    if (!fileSys.mkdirs(dir1)) {
      throw new IOException("Mkdirs failed to create " + root.toString());
    }
    writeFile(job, file1, (short)1, 1);
    writeFile(job, file2, (short)1, 1);

    // split it using a CombinedFile input format
    DummyFileInputFormat inFormat = new DummyFileInputFormat();
    inFormat.setInputPaths(job, root);

    // By default, we don't allow multi-level/recursive inputs
    boolean exceptionThrown = false;
    try {
      InputSplit[] splits = inFormat.getSplits(job, 1);
    } catch (Exception e) {
      exceptionThrown = true;
    }
    assertTrue("Exception should be thrown by default for scanning a "
        + "directory with directories inside.", exceptionThrown);

    // Enable multi-level/recursive inputs
    job.setBoolean("mapred.input.dir.recursive", true);
    InputSplit[] splits = inFormat.getSplits(job, 1);
    assertEquals(splits.length, 2);
  }

  static void writeFile(Configuration conf, Path name,
      short replication, int numBlocks) throws IOException {
    FileSystem fileSys = FileSystem.get(conf);

    FSDataOutputStream stm = fileSys.create(name, true,
                                            conf.getInt("io.file.buffer.size", 4096),
                                            replication, (long)BLOCKSIZE);
    for (int i = 0; i < numBlocks; i++) {
      stm.write(databuf);
    }
    stm.close();
    DFSTestUtil.waitReplication(fileSys, name, replication);
  }

  @Override
  public void tearDown() throws Exception {
    if (dfs != null) {
      dfs.shutdown();
      dfs = null;
    }
  }
}