/**
    * 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.Sets;
  import java.io.IOException;
  import java.util.Collection;
  import java.util.List;
  import java.util.Set;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileStatus;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.client.Admin;
  import org.apache.hadoop.hbase.client.Connection;
  import org.apache.hadoop.hbase.client.ConnectionFactory;
  import org.apache.hadoop.hbase.regionserver.HRegionFileSystem;
  import org.apache.hadoop.hbase.regionserver.StoreFileInfo;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  @InterfaceAudience.Private
  class MajorCompactionRequest {
  
    private static final Logger LOG = LoggerFactory.getLogger(MajorCompactionRequest.class);
  
    protected final Configuration configuration;
    protected final HRegionInfo region;
    private Set<String> stores;
  
    MajorCompactionRequest(Configuration configuration, HRegionInfo region) {
      this.configuration = configuration;
      this.region = region;
    }
  
    MajorCompactionRequest(Configuration configuration, HRegionInfo region,
        Set<String> stores) {
      this(configuration, region);
      this.stores = stores;
    }
  
    static Optional<MajorCompactionRequest> newRequest(Configuration configuration, HRegionInfo info,
        Set<String> stores, long timestamp) throws IOException {
      MajorCompactionRequest request =
          new MajorCompactionRequest(configuration, info, stores);
      return request.createRequest(configuration, stores, timestamp);
    }
  
    HRegionInfo getRegion() {
      return region;
    }
  
    Set<String> getStores() {
      return stores;
    }
  
    void setStores(Set<String> stores) {
      this.stores = stores;
    }
  
    Optional<MajorCompactionRequest> createRequest(Configuration configuration,
        Set<String> stores, long timestamp) throws IOException {
      Set<String> familiesToCompact = getStoresRequiringCompaction(stores, timestamp);
      MajorCompactionRequest request = null;
      if (!familiesToCompact.isEmpty()) {
        request = new MajorCompactionRequest(configuration, region, familiesToCompact);
      }
      return Optional.fromNullable(request);
    }
  
    Set<String> getStoresRequiringCompaction(Set<String> requestedStores, long timestamp)
        throws IOException {
      try(Connection connection = getConnection(configuration)) {
        HRegionFileSystem fileSystem = getFileSystem(connection);
        Set<String> familiesToCompact = Sets.newHashSet();
        for (String family : requestedStores) {
          if (shouldCFBeCompacted(fileSystem, family, timestamp)) {
            familiesToCompact.add(family);
          }
        }
       return familiesToCompact;
     }
   }
 
   boolean shouldCFBeCompacted(HRegionFileSystem fileSystem, String family, long ts)
       throws IOException {
 
     // do we have any store files?
     Collection<StoreFileInfo> storeFiles = fileSystem.getStoreFiles(family);
     if (storeFiles == null) {
       LOG.info("Excluding store: " + family + " for compaction for region:  " + fileSystem
           .getRegionInfo().getEncodedName(), " has no store files");
       return false;
     }
     // check for reference files
     if (fileSystem.hasReferences(family) && familyHasReferenceFile(fileSystem, family, ts)) {
       LOG.info("Including store: " + family + " with: " + storeFiles.size()
           + " files for compaction for region: " + fileSystem.getRegionInfo().getEncodedName());
       return true;
     }
     // check store file timestamps
     boolean includeStore = this.shouldIncludeStore(fileSystem, family, storeFiles, ts);
     if (!includeStore) {
       LOG.info("Excluding store: " + family + " for compaction for region:  " + fileSystem
           .getRegionInfo().getEncodedName() + " already compacted");
     }
     return includeStore;
   }
 
   protected boolean shouldIncludeStore(HRegionFileSystem fileSystem, String family,
       Collection<StoreFileInfo> storeFiles, long ts) throws IOException {
 
     for (StoreFileInfo storeFile : storeFiles) {
       if (storeFile.getModificationTime() < ts) {
         LOG.info("Including store: " + family + " with: " + storeFiles.size()
             + " files for compaction for region: "
             + fileSystem.getRegionInfo().getEncodedName());
         return true;
       }
     }
     return false;
   }
 
   Connection getConnection(Configuration configuration) throws IOException {
     return ConnectionFactory.createConnection(configuration);
   }
 
   protected boolean familyHasReferenceFile(HRegionFileSystem fileSystem, String family, long ts)
       throws IOException {
     List<Path> referenceFiles =
         getReferenceFilePaths(fileSystem.getFileSystem(), fileSystem.getStoreDir(family));
     for (Path referenceFile : referenceFiles) {
       FileStatus status = fileSystem.getFileSystem().getFileLinkStatus(referenceFile);
       if (status.getModificationTime() < ts) {
         LOG.info("Including store: " + family + " for compaction for region:  " + fileSystem
             .getRegionInfo().getEncodedName() + " (reference store files)");
         return true;
       }
     }
     return false;
 
   }
 
   List<Path> getReferenceFilePaths(FileSystem fileSystem, Path familyDir)
       throws IOException {
     return FSUtils.getReferenceFilePaths(fileSystem, familyDir);
   }
 
   HRegionFileSystem getFileSystem(Connection connection) throws IOException {
     Admin admin = connection.getAdmin();
     return HRegionFileSystem.openRegionFromFileSystem(admin.getConfiguration(),
         FSUtils.getCurrentFileSystem(admin.getConfiguration()),
         FSUtils.getTableDir(FSUtils.getRootDir(admin.getConfiguration()), region.getTable()),
         region, true);
   }
 
   @Override
   public String toString() {
     return "region: " + region.getEncodedName() + " store(s): " + stores;
   }
 }