/**
    * 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.util.compaction;
  
  import com.google.common.base.Optional;
  import com.google.common.collect.Maps;
  import java.io.IOException;
  import java.util.Collection;
  import java.util.Map;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.HColumnDescriptor;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.client.Connection;
  import org.apache.hadoop.hbase.regionserver.HRegionFileSystem;
  import org.apache.hadoop.hbase.regionserver.StoreFileInfo;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * This request helps determine if a region has to be compacted based on table's TTL.
   */
  @InterfaceAudience.Private
  public class MajorCompactionTTLRequest extends MajorCompactionRequest {
  
    private static final Logger LOG = LoggerFactory.getLogger(MajorCompactionTTLRequest.class);
  
    MajorCompactionTTLRequest(Configuration conf, HRegionInfo region) {
      super(conf, region);
    }
  
    static Optional<MajorCompactionRequest> newRequest(Configuration conf, HRegionInfo info,
        HTableDescriptor htd) throws IOException {
      MajorCompactionTTLRequest request = new MajorCompactionTTLRequest(conf, info);
      return request.createRequest(conf, htd);
    }
  
    private Optional<MajorCompactionRequest> createRequest(Configuration conf, HTableDescriptor htd)
        throws IOException {
      Map<String, Long> familiesToCompact = getStoresRequiringCompaction(htd);
      MajorCompactionRequest request = null;
      if (!familiesToCompact.isEmpty()) {
        LOG.debug("Compaction families for region: " + region + " CF: " + familiesToCompact.keySet());
        request = new MajorCompactionTTLRequest(conf, region);
      }
      return Optional.fromNullable(request);
    }
  
    Map<String, Long> getStoresRequiringCompaction(HTableDescriptor htd) throws IOException {
      try(Connection connection = getConnection(configuration)) {
        HRegionFileSystem fileSystem = getFileSystem(connection);
        Map<String, Long> familyTTLMap = Maps.newHashMap();
        for (HColumnDescriptor descriptor : htd.getColumnFamilies()) {
          long ts = getColFamilyCutoffTime(descriptor);
          // If the table's TTL is forever, lets not compact any of the regions.
          if (ts > 0 && shouldCFBeCompacted(fileSystem, descriptor.getNameAsString(), ts)) {
            familyTTLMap.put(descriptor.getNameAsString(), ts);
          }
        }
        return familyTTLMap;
      }
    }
  
    // If the CF has no TTL, return -1, else return the current time - TTL.
    private long getColFamilyCutoffTime(HColumnDescriptor colDesc) {
      if (colDesc.getTimeToLive() == HConstants.FOREVER) {
        return -1;
      }
      return System.currentTimeMillis() - (colDesc.getTimeToLive() * 1000L);
    }
  
    @Override
    protected boolean shouldIncludeStore(HRegionFileSystem fileSystem, String family,
        Collection<StoreFileInfo> storeFiles, long ts) throws IOException {
  
      for (StoreFileInfo storeFile : storeFiles) {
        // Lets only compact when all files are older than TTL
        if (storeFile.getModificationTime() >= ts) {
          LOG.info("There is atleast one file in store: " + family + " file: " + storeFile.getPath()
              + " with timestamp " + storeFile.getModificationTime()
              + " for region: " + fileSystem.getRegionInfo().getEncodedName()
             + " older than TTL: " + ts);
         return false;
       }
     }
     return true;
   }
 }