/**
    * 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.master.snapshot;
  
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  
  import java.io.IOException;
  import java.util.*;
  
  import com.google.common.collect.Iterables;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.fs.FileStatus;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.testclassification.MediumTests;
  import org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils;
  import org.apache.hadoop.hbase.snapshot.SnapshotReferenceUtil;
  import org.apache.hadoop.hbase.snapshot.SnapshotTestingUtils.SnapshotMock;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.junit.After;
  import org.junit.AfterClass;
  import org.junit.BeforeClass;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  /**
   * Test that we correctly reload the cache, filter directories, etc.
   */
  @Category(MediumTests.class)
  public class TestSnapshotFileCache {
  
    private static final Log LOG = LogFactory.getLog(TestSnapshotFileCache.class);
    private static final HBaseTestingUtility UTIL = new HBaseTestingUtility();
    private static FileSystem fs;
    private static Path rootDir;
  
    @BeforeClass
    public static void startCluster() throws Exception {
      UTIL.startMiniDFSCluster(1);
      fs = UTIL.getDFSCluster().getFileSystem();
      rootDir = UTIL.getDefaultRootDirPath();
    }
  
    @AfterClass
    public static void stopCluster() throws Exception {
      UTIL.shutdownMiniDFSCluster();
    }
  
    @After
    public void cleanupFiles() throws Exception {
      // cleanup the snapshot directory
      Path snapshotDir = SnapshotDescriptionUtils.getSnapshotsDir(rootDir);
      fs.delete(snapshotDir, true);
    }
  
    @Test(timeout = 10000000)
    public void testLoadAndDelete() throws IOException {
      // don't refresh the cache unless we tell it to
      long period = Long.MAX_VALUE;
      SnapshotFileCache cache = new SnapshotFileCache(fs, rootDir, period, 10000000,
          "test-snapshot-file-cache-refresh", new SnapshotFiles());
  
      createAndTestSnapshotV1(cache, "snapshot1a", false, true);
  
      createAndTestSnapshotV2(cache, "snapshot2a", false, true);
    }
  
    @Test
    public void testReloadModifiedDirectory() throws IOException {
      // don't refresh the cache unless we tell it to
      long period = Long.MAX_VALUE;
      SnapshotFileCache cache = new SnapshotFileCache(fs, rootDir, period, 10000000,
          "test-snapshot-file-cache-refresh", new SnapshotFiles());
  
      createAndTestSnapshotV1(cache, "snapshot1", false, true);
      // now delete the snapshot and add a file with a different name
      createAndTestSnapshotV1(cache, "snapshot1", false, false);
  
      createAndTestSnapshotV2(cache, "snapshot2", false, true);
      // now delete the snapshot and add a file with a different name
      createAndTestSnapshotV2(cache, "snapshot2", false, false);
   }
 
   @Test
   public void testSnapshotTempDirReload() throws IOException {
     long period = Long.MAX_VALUE;
     // This doesn't refresh cache until we invoke it explicitly
     SnapshotFileCache cache = new SnapshotFileCache(fs, rootDir, period, 10000000,
         "test-snapshot-file-cache-refresh", new SnapshotFiles());
 
     // Add a new non-tmp snapshot
     createAndTestSnapshotV1(cache, "snapshot0v1", false, false);
     createAndTestSnapshotV1(cache, "snapshot0v2", false, false);
   }
 
   class SnapshotFiles implements SnapshotFileCache.SnapshotFileInspector {
     public Collection<String> filesUnderSnapshot(final Path snapshotDir) throws IOException {
       Collection<String> files =  new HashSet<String>();
       files.addAll(SnapshotReferenceUtil.getHFileNames(UTIL.getConfiguration(), fs, snapshotDir));
       return files;
     }
   };
 
   private SnapshotMock.SnapshotBuilder createAndTestSnapshotV1(final SnapshotFileCache cache,
       final String name, final boolean tmp, final boolean removeOnExit) throws IOException {
     SnapshotMock snapshotMock = new SnapshotMock(UTIL.getConfiguration(), fs, rootDir);
     SnapshotMock.SnapshotBuilder builder = snapshotMock.createSnapshotV1(name, name);
     createAndTestSnapshot(cache, builder, tmp, removeOnExit);
     return builder;
   }
 
   private void createAndTestSnapshotV2(final SnapshotFileCache cache, final String name,
       final boolean tmp, final boolean removeOnExit) throws IOException {
     SnapshotMock snapshotMock = new SnapshotMock(UTIL.getConfiguration(), fs, rootDir);
     SnapshotMock.SnapshotBuilder builder = snapshotMock.createSnapshotV2(name, name);
     createAndTestSnapshot(cache, builder, tmp, removeOnExit);
   }
 
   private void createAndTestSnapshot(final SnapshotFileCache cache,
       final SnapshotMock.SnapshotBuilder builder,
       final boolean tmp, final boolean removeOnExit) throws IOException {
     List<Path> files = new ArrayList<Path>();
     for (int i = 0; i < 3; ++i) {
       for (Path filePath: builder.addRegion()) {
         files.add(filePath);
       }
     }
 
     // Finalize the snapshot
     builder.commit();
 
     // Make sure that all files are still present
     for (Path path: files) {
       Iterable<FileStatus> nonSnapshotFiles = getNonSnapshotFiles(cache, path);
       assertFalse("Cache didn't find " + path.getName(),
           Iterables.contains(nonSnapshotFiles, path.getName()));
     }
 
     FSUtils.logFileSystemState(fs, rootDir, LOG);
     if (removeOnExit) {
       LOG.debug("Deleting snapshot.");
       fs.delete(builder.getSnapshotsDir(), true);
       FSUtils.logFileSystemState(fs, rootDir, LOG);
 
       // The files should be in cache until next refresh
       for (Path filePath: files) {
         Iterable<FileStatus> nonSnapshotFiles = getNonSnapshotFiles(cache, filePath);
         assertFalse("Cache didn't find " + filePath.getName(), Iterables.contains(nonSnapshotFiles,
             filePath.getName()));
       }
 
       // then trigger a refresh
       cache.triggerCacheRefreshForTesting();
       // and not it shouldn't find those files
       for (Path filePath: files) {
         Iterable<FileStatus> nonSnapshotFiles = getNonSnapshotFiles(cache, filePath);
         assertTrue("Cache found '" + filePath.getName() + "', but it shouldn't have.",
             !Iterables.contains(nonSnapshotFiles, filePath.getName()));
       }
     }
   }
 
   private Iterable<FileStatus> getNonSnapshotFiles(SnapshotFileCache cache, Path storeFile)
       throws IOException {
     return cache.getUnreferencedFiles(
         Arrays.asList(FSUtils.listStatus(fs, storeFile.getParent())), null
     );
   }
 }