/*
 * 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.backup;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HBaseInterfaceAudience;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.backup.impl.BackupManager;
import org.apache.hadoop.hbase.backup.impl.BackupSystemTable;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.RegionInfo;
import org.apache.hadoop.hbase.coprocessor.ObserverContext;
import org.apache.hadoop.hbase.coprocessor.RegionCoprocessor;
import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment;
import org.apache.hadoop.hbase.coprocessor.RegionObserver;
import org.apache.hadoop.hbase.util.Pair;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * An Observer to facilitate backup operations
 */
@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
public class BackupObserver implements RegionCoprocessor, RegionObserver {
  private static final Logger LOG = LoggerFactory.getLogger(BackupObserver.class);

  @Override
  public Optional<RegionObserver> getRegionObserver() {
    return Optional.of(this);
  }

  @Override
  public void postBulkLoadHFile(ObserverContext<? extends RegionCoprocessorEnvironment> ctx,
    List<Pair<byte[], String>> stagingFamilyPaths, Map<byte[], List<Path>> finalPaths)
    throws IOException {
    Configuration cfg = ctx.getEnvironment().getConfiguration();
    if (finalPaths == null) {
      // there is no need to record state
      return;
    }
    if (!BackupManager.isBackupEnabled(cfg)) {
      LOG.debug("skipping recording bulk load in postBulkLoadHFile since backup is disabled");
      return;
    }

    registerBulkLoad(ctx, finalPaths);
  }

  @Override
  public void preCommitStoreFile(final ObserverContext<? extends RegionCoprocessorEnvironment> ctx,
    final byte[] family, final List<Pair<Path, Path>> pairs) throws IOException {
    Configuration cfg = ctx.getEnvironment().getConfiguration();
    if (pairs == null || pairs.isEmpty() || !BackupManager.isBackupEnabled(cfg)) {
      LOG.debug("skipping recording bulk load in preCommitStoreFile since backup is disabled");
      return;
    }

    List<Path> hfiles = new ArrayList<>(pairs.size());
    for (Pair<Path, Path> pair : pairs) {
      hfiles.add(pair.getSecond());
    }
    registerBulkLoad(ctx, Collections.singletonMap(family, hfiles));
  }

  private void registerBulkLoad(ObserverContext<? extends RegionCoprocessorEnvironment> ctx,
    Map<byte[], List<Path>> cfToHFilePaths) throws IOException {
    Configuration cfg = ctx.getEnvironment().getConfiguration();
    RegionInfo region = ctx.getEnvironment().getRegionInfo();
    TableName tableName = region.getTable();

    try (Connection connection = ConnectionFactory.createConnection(cfg);
      BackupSystemTable tbl = new BackupSystemTable(connection)) {
      Set<TableName> fullyBackedUpTables = tbl.getTablesIncludedInBackups();

      if (fullyBackedUpTables.contains(tableName)) {
        tbl.registerBulkLoad(tableName, region.getEncodedNameAsBytes(), cfToHFilePaths);
      } else {
        if (LOG.isTraceEnabled()) {
          LOG.trace("Table {} has not gone through full backup - skipping.", tableName);
        }
      }
    }
  }
}
