/**
    * 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 com.google.protobuf.InvalidProtocolBufferException;
  import java.io.IOException;
  import java.io.InterruptedIOException;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.Callable;
  import java.util.concurrent.Executor;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.ExecutorCompletionService;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FSDataInputStream;
  import org.apache.hadoop.fs.FSDataOutputStream;
  import org.apache.hadoop.fs.FileStatus;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.fs.PathFilter;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
  import org.apache.hadoop.hbase.protobuf.generated.SnapshotProtos.SnapshotRegionManifest;
  import org.apache.hadoop.hbase.regionserver.StoreFileInfo;
  import org.apache.hadoop.hbase.util.ByteStringer;
  import org.apache.hadoop.hbase.util.FSUtils;
  
  /**
   * DO NOT USE DIRECTLY. USE {@link SnapshotManifest}.
   *
   * Snapshot v2 layout format
   *  - Single Manifest file containing all the information of regions
   *  - In the online-snapshot case each region will write a "region manifest"
   *      /snapshotName/manifest.regionName
   */
  @InterfaceAudience.Private
  public final class SnapshotManifestV2 {
    private static final Log LOG = LogFactory.getLog(SnapshotManifestV2.class);
  
    public static final int DESCRIPTOR_VERSION = 2;
  
    public static final String SNAPSHOT_MANIFEST_PREFIX = "region-manifest.";
  
    private SnapshotManifestV2() {}
  
    static class ManifestBuilder implements SnapshotManifest.RegionVisitor<
                      SnapshotRegionManifest.Builder, SnapshotRegionManifest.FamilyFiles.Builder> {
      private final Configuration conf;
      private final Path snapshotDir;
      private final FileSystem fs;
  
      public ManifestBuilder(final Configuration conf, final FileSystem fs, final Path snapshotDir) {
        this.snapshotDir = snapshotDir;
        this.conf = conf;
        this.fs = fs;
      }
  
      public SnapshotRegionManifest.Builder regionOpen(final HRegionInfo regionInfo) {
        SnapshotRegionManifest.Builder manifest = SnapshotRegionManifest.newBuilder();
        manifest.setRegionInfo(HRegionInfo.convert(regionInfo));
        return manifest;
      }
  
      public void regionClose(final SnapshotRegionManifest.Builder region) throws IOException {
        // we should ensure the snapshot dir exist, maybe it has been deleted by master
        // see HBASE-16464
        if (fs.exists(snapshotDir)) {
          SnapshotRegionManifest manifest = region.build();
          FSDataOutputStream stream = fs.create(getRegionManifestPath(snapshotDir, manifest));
          try {
            manifest.writeTo(stream);
          } finally {
            stream.close();
          }
        } else {
          LOG.warn("can't write manifest without parent dir, maybe it has been deleted by master?");
        }
      }
  
     public SnapshotRegionManifest.FamilyFiles.Builder familyOpen(
         final SnapshotRegionManifest.Builder region, final byte[] familyName) {
       SnapshotRegionManifest.FamilyFiles.Builder family =
           SnapshotRegionManifest.FamilyFiles.newBuilder();
       family.setFamilyName(ByteStringer.wrap(familyName));
       return family;
     }
 
     public void familyClose(final SnapshotRegionManifest.Builder region,
         final SnapshotRegionManifest.FamilyFiles.Builder family) {
       region.addFamilyFiles(family.build());
     }
 
     public void storeFile(final SnapshotRegionManifest.Builder region,
         final SnapshotRegionManifest.FamilyFiles.Builder family, final StoreFileInfo storeFile)
         throws IOException {
       SnapshotRegionManifest.StoreFile.Builder sfManifest =
             SnapshotRegionManifest.StoreFile.newBuilder();
       sfManifest.setName(storeFile.getPath().getName());
       if (storeFile.isReference()) {
         sfManifest.setReference(storeFile.getReference().convert());
       }
       sfManifest.setFileSize(storeFile.getReferencedFileStatus(fs).getLen());
       family.addStoreFiles(sfManifest.build());
     }
   }
 
   static List<SnapshotRegionManifest> loadRegionManifests(final Configuration conf,
       final Executor executor,final FileSystem fs, final Path snapshotDir,
       final SnapshotDescription desc) throws IOException {
     FileStatus[] manifestFiles = FSUtils.listStatus(fs, snapshotDir, new PathFilter() {
       @Override
       public boolean accept(Path path) {
         return path.getName().startsWith(SNAPSHOT_MANIFEST_PREFIX);
       }
     });
 
     if (manifestFiles == null || manifestFiles.length == 0) return null;
 
     final ExecutorCompletionService<SnapshotRegionManifest> completionService =
       new ExecutorCompletionService<SnapshotRegionManifest>(executor);
     for (final FileStatus st: manifestFiles) {
       completionService.submit(new Callable<SnapshotRegionManifest>() {
         @Override
         public SnapshotRegionManifest call() throws IOException {
           FSDataInputStream stream = fs.open(st.getPath());
           try {
             return SnapshotRegionManifest.parseFrom(stream);
           } finally {
             stream.close();
           }
         }
       });
     }
 
     ArrayList<SnapshotRegionManifest> regionsManifest =
         new ArrayList<SnapshotRegionManifest>(manifestFiles.length);
     try {
       for (int i = 0; i < manifestFiles.length; ++i) {
         regionsManifest.add(completionService.take().get());
       }
     } catch (InterruptedException e) {
       throw new InterruptedIOException(e.getMessage());
     } catch (ExecutionException e) {
       Throwable t = e.getCause();
 
       if(t instanceof InvalidProtocolBufferException) {
         throw (InvalidProtocolBufferException)t;
       } else {
         IOException ex = new IOException("ExecutionException");
         ex.initCause(e.getCause());
         throw ex;
       }
     }
     return regionsManifest;
   }
 
   static void deleteRegionManifest(final FileSystem fs, final Path snapshotDir,
       final SnapshotRegionManifest manifest) throws IOException {
     fs.delete(getRegionManifestPath(snapshotDir, manifest), true);
   }
 
   private static Path getRegionManifestPath(final Path snapshotDir,
       final SnapshotRegionManifest manifest) {
     String regionName = SnapshotManifest.getRegionNameFromManifest(manifest);
     return new Path(snapshotDir, SNAPSHOT_MANIFEST_PREFIX + regionName);
   }
 }