/**
    * 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.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  import static org.mockito.Mockito.mock;
  import static org.mockito.Mockito.when;
  
  import java.io.IOException;
  import java.util.*;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import com.google.common.collect.Iterables;
  import com.google.common.collect.Lists;
  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.HRegionInfo;
  import org.apache.hadoop.hbase.protobuf.generated.SnapshotProtos;
  import org.apache.hadoop.hbase.testclassification.MediumTests;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
  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 long sequenceId = 0;
    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);
      createAndTestSnapshotV1(cache, "snapshot1b", true, true);
  
      createAndTestSnapshotV2(cache, "snapshot2a", false, true);
      createAndTestSnapshotV2(cache, "snapshot2b", true, 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);
 
     // Add a new tmp snapshot
     createAndTestSnapshotV2(cache, "snapshot1", true, false);
 
     // Add another tmp snapshot
     createAndTestSnapshotV2(cache, "snapshot2", true, false);
   }
 
   @Test
   public void testWeNeverCacheTmpDirAndLoadIt() throws Exception {
 
     final AtomicInteger count = new AtomicInteger(0);
     // 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()) {
       @Override
       List<String> getSnapshotsInProgress() throws IOException {
         List<String> result = super.getSnapshotsInProgress();
         count.incrementAndGet();
         return result;
       }
 
       @Override public void triggerCacheRefreshForTesting() {
         super.triggerCacheRefreshForTesting();
       }
     };
 
     SnapshotMock.SnapshotBuilder complete =
         createAndTestSnapshotV1(cache, "snapshot", false, false);
 
     SnapshotMock.SnapshotBuilder inProgress =
         createAndTestSnapshotV1(cache, "snapshotInProgress", true, false);
 
     int countBeforeCheck = count.get();
 
     FSUtils.logFileSystemState(fs, rootDir, LOG);
 
     List<FileStatus> allStoreFiles = getStoreFilesForSnapshot(complete);
     Iterable<FileStatus> deletableFiles = cache.getUnreferencedFiles(allStoreFiles);
     assertTrue(Iterables.isEmpty(deletableFiles));
     // no need for tmp dir check as all files are accounted for.
     assertEquals(0, count.get() - countBeforeCheck);
 
 
     // add a random file to make sure we refresh
     FileStatus randomFile = mockStoreFile(UUID.randomUUID().toString());
     allStoreFiles.add(randomFile);
     deletableFiles = cache.getUnreferencedFiles(allStoreFiles);
     assertEquals(randomFile, Iterables.getOnlyElement(deletableFiles));
     assertEquals(1, count.get() - countBeforeCheck); // we check the tmp directory
   }
 
   private List<FileStatus> getStoreFilesForSnapshot(SnapshotMock.SnapshotBuilder builder)
       throws IOException {
     final List<FileStatus> allStoreFiles = Lists.newArrayList();
     SnapshotReferenceUtil
         .visitReferencedFiles(UTIL.getConfiguration(), fs, builder.getSnapshotsDir(),
             new SnapshotReferenceUtil.SnapshotVisitor() {
               @Override public void storeFile(HRegionInfo regionInfo, String familyName,
                   SnapshotProtos.SnapshotRegionManifest.StoreFile storeFile) throws IOException {
                 FileStatus status = mockStoreFile(storeFile.getName());
                 allStoreFiles.add(status);
               }
             });
     return allStoreFiles;
   }
 
   private FileStatus mockStoreFile(String storeFileName) {
     FileStatus status = mock(FileStatus.class);
     Path path = mock(Path.class);
     when(path.getName()).thenReturn(storeFileName);
     when(status.getPath()).thenReturn(path);
     return status;
   }
 
   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()) {
         String fileName = filePath.getName();
         if (tmp) {
           // We should be able to find all the files while the snapshot creation is in-progress
           FSUtils.logFileSystemState(fs, rootDir, LOG);
           Iterable<FileStatus> nonSnapshot = getNonSnapshotFiles(cache, filePath);
           assertFalse("Cache didn't find " + fileName, Iterables.contains(nonSnapshot, fileName));
         }
         files.add(filePath);
       }
     }
 
     // Finalize the snapshot
     if (!tmp) {
       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()))
     );
   }
 }