/**
    * Copyright The Apache Software Foundation
    *
    * 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.io.hfile.bucket;
  
  import static org.junit.Assert.assertTrue;
  
  import java.io.File;
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.hadoop.hbase.testclassification.SmallTests;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  /**
   * Basic test for {@link FileIOEngine}
   */
  @Category(SmallTests.class)
  public class TestFileIOEngine {
    @Test
    public void testFileIOEngine() throws IOException {
      long totalCapacity = 6 * 1024 * 1024; // 6 MB
      String[] filePaths = { "testFileIOEngine1", "testFileIOEngine2",
          "testFileIOEngine3" };
      long sizePerFile = totalCapacity / filePaths.length; // 2 MB per File
      List<Long> boundaryStartPositions = new ArrayList<Long>();
      boundaryStartPositions.add(0L);
      for (int i = 1; i < filePaths.length; i++) {
        boundaryStartPositions.add(sizePerFile * i - 1);
        boundaryStartPositions.add(sizePerFile * i);
        boundaryStartPositions.add(sizePerFile * i + 1);
      }
      List<Long> boundaryStopPositions = new ArrayList<Long>();
      for (int i = 1; i < filePaths.length; i++) {
        boundaryStopPositions.add(sizePerFile * i - 1);
        boundaryStopPositions.add(sizePerFile * i);
        boundaryStopPositions.add(sizePerFile * i + 1);
      }
      boundaryStopPositions.add(sizePerFile * filePaths.length - 1);
      FileIOEngine fileIOEngine = new FileIOEngine(totalCapacity, filePaths);
      try {
        for (int i = 0; i < 500; i++) {
          int len = (int) Math.floor(Math.random() * 100);
          long offset = (long) Math.floor(Math.random() * totalCapacity % (totalCapacity - len));
          if (i < boundaryStartPositions.size()) {
            // make the boundary start positon
            offset = boundaryStartPositions.get(i);
          } else if ((i - boundaryStartPositions.size()) < boundaryStopPositions.size()) {
            // make the boundary stop positon
            offset = boundaryStopPositions.get(i - boundaryStartPositions.size()) - len + 1;
          } else if (i % 2 == 0) {
            // make the cross-files block writing/reading
            offset = Math.max(1, i % filePaths.length) * sizePerFile - len / 2;
          }
          byte[] data1 = new byte[len];
          for (int j = 0; j < data1.length; ++j) {
            data1[j] = (byte) (Math.random() * 255);
          }
          byte[] data2 = new byte[len];
          fileIOEngine.write(ByteBuffer.wrap(data1), offset);
          fileIOEngine.read(ByteBuffer.wrap(data2), offset);
          for (int j = 0; j < data1.length; ++j) {
            assertTrue(data1[j] == data2[j]);
          }
        }
      } finally {
        fileIOEngine.shutdown();
        for (String filePath : filePaths) {
          File file = new File(filePath);
          if (file.exists()) {
            file.delete();
          }
        }
      }
  
    }
  }