/**
 * 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.hdfs.web;

import java.io.IOException;
import java.util.Random;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.logging.impl.Log4JLogger;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.hdfs.TestDFSClientRetries;
import org.apache.hadoop.hdfs.server.namenode.web.resources.NamenodeWebHdfsMethods;
import org.apache.log4j.Level;
import org.junit.Assert;
import org.junit.Test;

/** Test WebHDFS */
public class TestWebHDFS {
  static final Log LOG = LogFactory.getLog(TestWebHDFS.class);
  
  static final Random RANDOM = new Random();
  
  static final long systemStartTime = System.nanoTime();

  /** A timer for measuring performance. */
  static class Ticker {
    final String name;
    final long startTime = System.nanoTime();
    private long previousTick = startTime;

    Ticker(final String name, String format, Object... args) {
      this.name = name;
      LOG.info(String.format("\n\n%s START: %s\n",
          name, String.format(format, args)));
    }

    void tick(final long nBytes, String format, Object... args) {
      final long now = System.nanoTime();
      if (now - previousTick > 10000000000L) {
        previousTick = now;
        final double mintues = (now - systemStartTime)/60000000000.0;
        LOG.info(String.format("\n\n%s %.2f min) %s %s\n", name, mintues,
            String.format(format, args), toMpsString(nBytes, now)));
      }
    }
    
    void end(final long nBytes) {
      final long now = System.nanoTime();
      final double seconds = (now - startTime)/1000000000.0;
      LOG.info(String.format("\n\n%s END: duration=%.2fs %s\n",
          name, seconds, toMpsString(nBytes, now)));
    }
    
    String toMpsString(final long nBytes, final long now) {
      final double mb = nBytes/(double)(1<<20);
      final double mps = mb*1000000000.0/(now - startTime);
      return String.format("[nBytes=%.2fMB, speed=%.2fMB/s]", mb, mps);
    }
  }

  @Test(timeout=300000)
  public void testLargeFile() throws Exception {
    largeFileTest(200L << 20); //200MB file length
  }

  /** Test read and write large files. */
  static void largeFileTest(final long fileLength) throws Exception {
    final Configuration conf = WebHdfsTestUtil.createConf();

    final MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
        .numDataNodes(3)
        .build();
    try {
      cluster.waitActive();

      final FileSystem fs = WebHdfsTestUtil.getWebHdfsFileSystem(conf);
      final Path dir = new Path("/test/largeFile");
      Assert.assertTrue(fs.mkdirs(dir));

      final byte[] data = new byte[1 << 20];
      RANDOM.nextBytes(data);

      final byte[] expected = new byte[2 * data.length];
      System.arraycopy(data, 0, expected, 0, data.length);
      System.arraycopy(data, 0, expected, data.length, data.length);

      final Path p = new Path(dir, "file");
      final Ticker t = new Ticker("WRITE", "fileLength=" + fileLength);
      final FSDataOutputStream out = fs.create(p);
      try {
        long remaining = fileLength;
        for(; remaining > 0;) {
          t.tick(fileLength - remaining, "remaining=%d", remaining);
          
          final int n = (int)Math.min(remaining, data.length);
          out.write(data, 0, n);
          remaining -= n;
        }
      } finally {
        out.close();
      }
      t.end(fileLength);
  
      Assert.assertEquals(fileLength, fs.getFileStatus(p).getLen());

      final long smallOffset = RANDOM.nextInt(1 << 20) + (1 << 20);
      final long largeOffset = fileLength - smallOffset;
      final byte[] buf = new byte[data.length];

      verifySeek(fs, p, largeOffset, fileLength, buf, expected);
      verifySeek(fs, p, smallOffset, fileLength, buf, expected);
  
      verifyPread(fs, p, largeOffset, fileLength, buf, expected);
    } finally {
      cluster.shutdown();
    }
  }

  static void checkData(long offset, long remaining, int n,
      byte[] actual, byte[] expected) {
    if (RANDOM.nextInt(100) == 0) {
      int j = (int)(offset % actual.length);
      for(int i = 0; i < n; i++) {
        if (expected[j] != actual[i]) {
          Assert.fail("expected[" + j + "]=" + expected[j]
              + " != actual[" + i + "]=" + actual[i]
              + ", offset=" + offset + ", remaining=" + remaining + ", n=" + n);
        }
        j++;
      }
    }
  }

  /** test seek */
  static void verifySeek(FileSystem fs, Path p, long offset, long length,
      byte[] buf, byte[] expected) throws IOException { 
    long remaining = length - offset;
    long checked = 0;
    LOG.info("XXX SEEK: offset=" + offset + ", remaining=" + remaining);

    final Ticker t = new Ticker("SEEK", "offset=%d, remaining=%d",
        offset, remaining);
    final FSDataInputStream in = fs.open(p, 64 << 10);
    in.seek(offset);
    for(; remaining > 0; ) {
      t.tick(checked, "offset=%d, remaining=%d", offset, remaining);
      final int n = (int)Math.min(remaining, buf.length);
      in.readFully(buf, 0, n);
      checkData(offset, remaining, n, buf, expected);

      offset += n;
      remaining -= n;
      checked += n;
    }
    in.close();
    t.end(checked);
  }

  static void verifyPread(FileSystem fs, Path p, long offset, long length,
      byte[] buf, byte[] expected) throws IOException {
    long remaining = length - offset;
    long checked = 0;
    LOG.info("XXX PREAD: offset=" + offset + ", remaining=" + remaining);

    final Ticker t = new Ticker("PREAD", "offset=%d, remaining=%d",
        offset, remaining);
    final FSDataInputStream in = fs.open(p, 64 << 10);
    for(; remaining > 0; ) {
      t.tick(checked, "offset=%d, remaining=%d", offset, remaining);
      final int n = (int)Math.min(remaining, buf.length);
      in.readFully(offset, buf, 0, n);
      checkData(offset, remaining, n, buf, expected);

      offset += n;
      remaining -= n;
      checked += n;
    }
    in.close();
    t.end(checked);
  }

  /** Test client retry with namenode restarting. */
  @Test(timeout=300000)
  public void testNamenodeRestart() throws Exception {
    ((Log4JLogger)NamenodeWebHdfsMethods.LOG).getLogger().setLevel(Level.ALL);
    final Configuration conf = WebHdfsTestUtil.createConf();
    TestDFSClientRetries.namenodeRestartTest(conf, true);
  }
}
