/*
 * 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.fs.contract;

import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocatedFileStatus;
import org.apache.hadoop.fs.Path;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.test.LambdaTestUtils;

import static org.apache.hadoop.fs.contract.ContractTestUtils.createFile;
import static org.apache.hadoop.fs.contract.ContractTestUtils.dataset;
import static org.apache.hadoop.fs.contract.ContractTestUtils.deleteChildren;
import static org.apache.hadoop.fs.contract.ContractTestUtils.dumpStats;
import static org.apache.hadoop.fs.contract.ContractTestUtils.listChildren;
import static org.apache.hadoop.fs.contract.ContractTestUtils.toList;
import static org.apache.hadoop.fs.contract.ContractTestUtils.treeWalk;

/**
 * This class does things to the root directory.
 * Only subclass this for tests against transient filesystems where
 * you don't care about the data.
 */
public abstract class AbstractContractRootDirectoryTest extends AbstractFSContractTestBase {
  private static final Logger LOG =
      LoggerFactory.getLogger(AbstractContractRootDirectoryTest.class);
  public static final int OBJECTSTORE_RETRY_TIMEOUT = 30000;

  @Override
  public void setup() throws Exception {
    super.setup();
    skipIfUnsupported(TEST_ROOT_TESTS_ENABLED);
  }

  @Test
  public void testMkDirDepth1() throws Throwable {
    FileSystem fs = getFileSystem();
    Path dir = new Path("/testmkdirdepth1");
    assertPathDoesNotExist("directory already exists", dir);
    fs.mkdirs(dir);
    assertIsDirectory(dir);
    assertPathExists("directory already exists", dir);
    assertDeleted(dir, true);
  }

  @Test
  public void testRmEmptyRootDirRecursive() throws Throwable {
    //extra sanity checks here to avoid support calls about complete loss of data
    skipIfUnsupported(TEST_ROOT_TESTS_ENABLED);
    Path root = new Path("/");
    assertIsDirectory(root);
    boolean deleted = getFileSystem().delete(root, true);
    LOG.info("rm -r / of empty dir result is {}", deleted);
    assertIsDirectory(root);
  }

  @Test
  public void testRmEmptyRootDirNonRecursive() throws Throwable {
    // extra sanity checks here to avoid support calls about complete loss
    // of data
    skipIfUnsupported(TEST_ROOT_TESTS_ENABLED);
    final Path root = new Path("/");
    assertIsDirectory(root);
    // make sure the directory is clean. This includes some retry logic
    // to forgive blobstores whose listings can be out of sync with the file
    // status;
    final FileSystem fs = getFileSystem();
    final AtomicInteger iterations = new AtomicInteger(0);
    final FileStatus[] originalChildren = listChildren(fs, root);
    LambdaTestUtils.eventually(
        OBJECTSTORE_RETRY_TIMEOUT,
        new Callable<Void>() {
          @Override
          public Void call() throws Exception {
            FileStatus[] deleted = deleteChildren(fs, root, true);
            FileStatus[] children = listChildren(fs, root);
            if (children.length > 0) {
              fail(String.format(
                  "After %d attempts: listing after rm /* not empty"
                      + "\n%s\n%s\n%s",
                  iterations.incrementAndGet(),
                  dumpStats("final", children),
                  dumpStats("deleted", deleted),
                  dumpStats("original", originalChildren)));
            }
            return null;
          }
        },
        new LambdaTestUtils.ProportionalRetryInterval(50, 1000));
    // then try to delete the empty one
    boolean deleted = fs.delete(root, false);
    LOG.info("rm / of empty dir result is {}", deleted);
    assertIsDirectory(root);
  }

  @Test
  public void testRmNonEmptyRootDirNonRecursive() throws Throwable {
    //extra sanity checks here to avoid support calls about complete loss of data
    skipIfUnsupported(TEST_ROOT_TESTS_ENABLED);
    Path root = new Path("/");
    String touchfile = "/testRmNonEmptyRootDirNonRecursive";
    Path file = new Path(touchfile);
    ContractTestUtils.touch(getFileSystem(), file);
    assertIsDirectory(root);
    try {
      boolean deleted = getFileSystem().delete(root, false);
      fail("non recursive delete should have raised an exception," +
           " but completed with exit code " + deleted);
    } catch (IOException e) {
      //expected
      handleExpectedException(e);
      // and the file must still be present
      assertIsFile(file);
    } finally {
      getFileSystem().delete(file, false);
    }
    assertIsDirectory(root);
  }

  @Test
  public void testRmRootRecursive() throws Throwable {
    //extra sanity checks here to avoid support calls about complete loss of data
    skipIfUnsupported(TEST_ROOT_TESTS_ENABLED);
    Path root = new Path("/");
    assertIsDirectory(root);
    Path file = new Path("/testRmRootRecursive");
    ContractTestUtils.touch(getFileSystem(), file);
    boolean deleted = getFileSystem().delete(root, true);
    assertIsDirectory(root);
    LOG.info("rm -rf / result is {}", deleted);
    if (deleted) {
      assertPathDoesNotExist("expected file to be deleted", file);
    } else {
      assertPathExists("expected file to be preserved", file);;
    }
  }

  @Test
  public void testCreateFileOverRoot() throws Throwable {
    //extra sanity checks here to avoid support calls about complete loss of data
    skipIfUnsupported(TEST_ROOT_TESTS_ENABLED);
    Path root = new Path("/");
    byte[] dataset = dataset(1024, ' ', 'z');
    try {
      createFile(getFileSystem(), root, false, dataset);
      fail("expected an exception, got a file created over root: " + ls(root));
    } catch (IOException e) {
      //expected
      handleExpectedException(e);
    }
    assertIsDirectory(root);
  }

  @Test
  public void testListEmptyRootDirectory() throws IOException {
    skipIfUnsupported(TEST_ROOT_TESTS_ENABLED);
    FileSystem fs = getFileSystem();
    Path root = new Path("/");
    FileStatus[] statuses = fs.listStatus(root);
    for (FileStatus status : statuses) {
      ContractTestUtils.assertDeleted(fs, status.getPath(), true);
    }
    assertEquals("listStatus on empty root-directory returned a non-empty list",
        0, fs.listStatus(root).length);
    assertFalse("listFiles(/, false).hasNext",
        fs.listFiles(root, false).hasNext());
    assertFalse("listFiles(/, true).hasNext",
        fs.listFiles(root, true).hasNext());
    assertFalse("listLocatedStatus(/).hasNext",
        fs.listLocatedStatus(root).hasNext());
    assertIsDirectory(root);
  }

  @Test
  public void testSimpleRootListing() throws IOException {
    describe("test the nonrecursive root listing calls");
    FileSystem fs = getFileSystem();
    Path root = new Path("/");
    FileStatus[] statuses = fs.listStatus(root);
    List<LocatedFileStatus> locatedStatusList = toList(
        fs.listLocatedStatus(root));
    assertEquals(statuses.length, locatedStatusList.size());
    List<LocatedFileStatus> fileList = toList(fs.listFiles(root, false));
    assertTrue(fileList.size() <= statuses.length);
  }

  @Test
  public void testRecursiveRootListing() throws IOException {
    describe("test a recursive root directory listing");
    FileSystem fs = getFileSystem();
    Path root = new Path("/");
    ContractTestUtils.TreeScanResults
        listing = new ContractTestUtils.TreeScanResults(
        fs.listFiles(root, true));
    describe("verifying consistency with treewalk's files");
    ContractTestUtils.TreeScanResults treeWalk = treeWalk(fs, root);
    treeWalk.assertFieldsEquivalent("files", listing,
        treeWalk.getFiles(),
        listing.getFiles());
  }

}