/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the "License"). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio.client;

import alluxio.AlluxioURI;
import alluxio.LocalAlluxioClusterResource;
import alluxio.PropertyKey;
import alluxio.BaseIntegrationTest;
import alluxio.client.file.FileInStream;
import alluxio.client.file.FileOutStream;
import alluxio.client.file.FileSystem;
import alluxio.client.file.URIStatus;
import alluxio.client.file.options.CreateFileOptions;
import alluxio.client.file.options.OpenFileOptions;
import alluxio.underfs.UnderFileSystem;
import alluxio.underfs.UnderFileSystemCluster;
import alluxio.underfs.hdfs.LocalMiniDFSCluster;
import alluxio.util.io.BufferUtils;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Rule;

import java.io.InputStream;

/**
 * Abstract classes for all integration tests of {@link FileOutStream}.
 */
public abstract class AbstractFileOutStreamIntegrationTest extends BaseIntegrationTest {
  protected static final int MIN_LEN = 0;
  protected static final int MAX_LEN = 255;
  protected static final int DELTA = 32;
  protected static final int BUFFER_BYTES = 100;

  @Rule
  public LocalAlluxioClusterResource mLocalAlluxioClusterResource =
      new LocalAlluxioClusterResource.Builder()
          .setProperty(PropertyKey.USER_FILE_BUFFER_BYTES, BUFFER_BYTES)
          .build();

  protected FileSystem mFileSystem = null;

  @Before
  public void before() throws Exception {
    mFileSystem = mLocalAlluxioClusterResource.get().getClient();
  }

  /**
   * Helper to write an Alluxio file with stream of bytes of increasing byte value.
   *
   * @param filePath path of the tmp file
   * @param fileLen length of the file
   * @param op options to create file
   */
  protected void writeIncreasingBytesToFile(AlluxioURI filePath, int fileLen, CreateFileOptions op)
      throws Exception {
    try (FileOutStream os = mFileSystem.createFile(filePath, op)) {
      for (int k = 0; k < fileLen; k++) {
        os.write((byte) k);
      }
    }
  }

  /**
   * Helper to write an Alluxio file with one increasing byte array, using a single
   * {@link FileOutStream#write(byte[], int, int)} invocation.
   *
   * @param filePath path of the tmp file
   * @param fileLen length of the file
   * @param op options to create file
   */
  protected void writeIncreasingByteArrayToFile(AlluxioURI filePath, int fileLen,
      CreateFileOptions op) throws Exception {
    try (FileOutStream os = mFileSystem.createFile(filePath, op)) {
      os.write(BufferUtils.getIncreasingByteArray(fileLen));
    }
  }

  /**
   * Helper to write an Alluxio file with one increasing byte array, but using two separate
   * {@link FileOutStream#write(byte[], int, int)} invocations.
   *
   * @param filePath path of the tmp file
   * @param fileLen length of the file
   * @param op options to create file
   */
  protected void writeTwoIncreasingByteArraysToFile(AlluxioURI filePath, int fileLen,
      CreateFileOptions op) throws Exception {
    try (FileOutStream os = mFileSystem.createFile(filePath, op)) {
      int len1 = fileLen / 2;
      int len2 = fileLen - len1;
      os.write(BufferUtils.getIncreasingByteArray(0, len1), 0, len1);
      os.write(BufferUtils.getIncreasingByteArray(len1, len2), 0, len2);
    }
  }

  /**
   * Checks the given file exists in Alluxio storage and expects its content to be an increasing
   * array of the given length.
   *
   * @param filePath path of the tmp file
   * @param fileLen length of the file
   */
  protected void checkFileInAlluxio(AlluxioURI filePath, int fileLen) throws Exception {
    URIStatus status = mFileSystem.getStatus(filePath);
    Assert.assertEquals(fileLen, status.getLength());
    try (FileInStream is = mFileSystem
        .openFile(filePath, OpenFileOptions.defaults().setReadType(ReadType.NO_CACHE))) {
      byte[] res = new byte[(int) status.getLength()];
      Assert.assertEquals((int) status.getLength(), is.read(res));
      Assert.assertTrue(BufferUtils.equalIncreasingByteArray(fileLen, res));
    }
  }

  /**
   * Checks the given file exists in under storage and expects its content to be an increasing
   * array of the given length.
   *
   * @param filePath path of the tmp file
   * @param fileLen length of the file
   */
  protected void checkFileInUnderStorage(AlluxioURI filePath, int fileLen) throws Exception {
    URIStatus status = mFileSystem.getStatus(filePath);
    String checkpointPath = status.getUfsPath();
    UnderFileSystem ufs = UnderFileSystem.Factory.create(checkpointPath);

    try (InputStream is = ufs.open(checkpointPath)) {
      byte[] res = new byte[(int) status.getLength()];
      String underFSClass = UnderFileSystemCluster.getUnderFSClass();
      if ((LocalMiniDFSCluster.class.getName().equals(underFSClass)) && 0 == res.length) {
        // Returns -1 for zero-sized byte array to indicate no more bytes available here.
        Assert.assertEquals(-1, is.read(res));
      } else {
        Assert.assertEquals((int) status.getLength(), is.read(res));
      }
      Assert.assertTrue(BufferUtils.equalIncreasingByteArray(fileLen, res));
    }
  }
}