/**
    * 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.snapshot;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertTrue;
  
  import java.io.IOException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.testclassification.SmallTests;
  import org.apache.hadoop.hbase.errorhandling.ForeignExceptionDispatcher;
  import org.apache.hadoop.hbase.io.HFileLink;
  import org.apache.hadoop.hbase.monitoring.MonitoredTask;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
  import org.apache.hadoop.hbase.regionserver.StoreFileInfo;
  import org.apache.hadoop.hbase.snapshot.SnapshotTestingUtils.SnapshotMock;
  import org.apache.hadoop.hbase.util.FSTableDescriptors;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.junit.After;
  import org.junit.Before;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  import org.mockito.Mockito;
  
  /**
   * Test the restore/clone operation from a file-system point of view.
   */
  @Category(SmallTests.class)
  public class TestRestoreSnapshotHelper {
    final Log LOG = LogFactory.getLog(getClass());
  
    private final static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
    private final static String TEST_HFILE = "abc";
  
    private Configuration conf;
    private Path archiveDir;
    private FileSystem fs;
    private Path rootDir;
  
    @Before
    public void setup() throws Exception {
      rootDir = TEST_UTIL.getDataTestDir("testRestore");
      archiveDir = new Path(rootDir, HConstants.HFILE_ARCHIVE_DIRECTORY);
      fs = TEST_UTIL.getTestFileSystem();
      conf = TEST_UTIL.getConfiguration();
      FSUtils.setRootDir(conf, rootDir);
    }
  
    @After
    public void tearDown() throws Exception {
      fs.delete(TEST_UTIL.getDataTestDir(), true);
    }
  
    @Test
    public void testRestore() throws IOException {
      restoreAndVerify("snapshot", "testRestore");
    }
  
    @Test
    public void testRestoreWithNamespace() throws IOException {
      restoreAndVerify("snapshot", "namespace1:testRestoreWithNamespace");
    }
  
    private void restoreAndVerify(final String snapshotName, final String tableName)
        throws IOException {
      // Test Rolling-Upgrade like Snapshot.
      // half machines writing using v1 and the others using v2 format.
      SnapshotMock snapshotMock = new SnapshotMock(TEST_UTIL.getConfiguration(), fs, rootDir);
      SnapshotMock.SnapshotBuilder builder = snapshotMock.createSnapshotV2("snapshot", tableName);
      builder.addRegionV1();
      builder.addRegionV2();
      builder.addRegionV2();
      builder.addRegionV1();
      Path snapshotDir = builder.commit();
      HTableDescriptor htd = builder.getTableDescriptor();
      SnapshotDescription desc = builder.getSnapshotDescription();
 
     // Test clone a snapshot
     HTableDescriptor htdClone = snapshotMock.createHtd("testtb-clone");
     testRestore(snapshotDir, desc, htdClone);
     verifyRestore(rootDir, htd, htdClone);
 
     // Test clone a clone ("link to link")
     SnapshotDescription cloneDesc = SnapshotDescription.newBuilder()
         .setName("cloneSnapshot")
         .setTable("testtb-clone")
         .build();
     Path cloneDir = FSUtils.getTableDir(rootDir, htdClone.getTableName());
     HTableDescriptor htdClone2 = snapshotMock.createHtd("testtb-clone2");
     testRestore(cloneDir, cloneDesc, htdClone2);
     verifyRestore(rootDir, htd, htdClone2);
   }
 
   private void verifyRestore(final Path rootDir, final HTableDescriptor sourceHtd,
       final HTableDescriptor htdClone) throws IOException {
     String[] files = SnapshotTestingUtils.listHFileNames(fs,
       FSUtils.getTableDir(rootDir, htdClone.getTableName()));
     assertEquals(12, files.length);
     for (int i = 0; i < files.length; i += 2) {
       String linkFile = files[i];
       String refFile = files[i+1];
       assertTrue(linkFile + " should be a HFileLink", HFileLink.isHFileLink(linkFile));
       assertTrue(refFile + " should be a Referene", StoreFileInfo.isReference(refFile));
       assertEquals(sourceHtd.getTableName(), HFileLink.getReferencedTableName(linkFile));
       Path refPath = getReferredToFile(refFile);
       LOG.debug("get reference name for file " + refFile + " = " + refPath);
       assertTrue(refPath.getName() + " should be a HFileLink", HFileLink.isHFileLink(refPath.getName()));
       assertEquals(linkFile, refPath.getName());
     }
   }
 
   /**
    * Execute the restore operation
    * @param snapshotDir The snapshot directory to use as "restore source"
    * @param sd The snapshot descriptor
    * @param htdClone The HTableDescriptor of the table to restore/clone.
    */
   public void testRestore(final Path snapshotDir, final SnapshotDescription sd,
       final HTableDescriptor htdClone) throws IOException {
     LOG.debug("pre-restore table=" + htdClone.getTableName() + " snapshot=" + snapshotDir);
     FSUtils.logFileSystemState(fs, rootDir, LOG);
 
     new FSTableDescriptors(conf).createTableDescriptor(htdClone);
     RestoreSnapshotHelper helper = getRestoreHelper(rootDir, snapshotDir, sd, htdClone);
     helper.restoreHdfsRegions();
 
     LOG.debug("post-restore table=" + htdClone.getTableName() + " snapshot=" + snapshotDir);
     FSUtils.logFileSystemState(fs, rootDir, LOG);
   }
 
   /**
    * Initialize the restore helper, based on the snapshot and table information provided.
    */
   private RestoreSnapshotHelper getRestoreHelper(final Path rootDir, final Path snapshotDir,
       final SnapshotDescription sd, final HTableDescriptor htdClone) throws IOException {
     ForeignExceptionDispatcher monitor = Mockito.mock(ForeignExceptionDispatcher.class);
     MonitoredTask status = Mockito.mock(MonitoredTask.class);
 
     SnapshotManifest manifest = SnapshotManifest.open(conf, fs, snapshotDir, sd);
     return new RestoreSnapshotHelper(conf, fs, manifest,
       htdClone, rootDir, monitor, status);
   }
 
   private Path getReferredToFile(final String referenceName) {
     Path fakeBasePath = new Path(new Path("table", "region"), "cf");
     return StoreFileInfo.getReferredToFile(new Path(fakeBasePath, referenceName));
   }
 }