/**
    * 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.regionserver;
  
  import java.io.Closeable;
  import java.io.IOException;
  import java.util.Map;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.ScheduledFuture;
  import java.util.concurrent.TimeUnit;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.CompatibilitySingletonFactory;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
  import org.apache.hadoop.metrics2.MetricsExecutor;
  
  @InterfaceAudience.Private
  public class MetricsRegionWrapperImpl implements MetricsRegionWrapper, Closeable {
  
    private static final Log LOG = LogFactory.getLog(MetricsRegionWrapperImpl.class);
  
    public static final int PERIOD = 45;
    public static final String UNKNOWN = "unknown";
  
    private final HRegion region;
    private ScheduledExecutorService executor;
    private Runnable runnable;
    private long numStoreFiles;
    private long memstoreSize;
    private long storeFileSize;
    private long maxStoreFileAge;
    private long minStoreFileAge;
    private long avgStoreFileAge;
    private long numReferenceFiles;
  
    private ScheduledFuture<?> regionMetricsUpdateTask;
  
    public MetricsRegionWrapperImpl(HRegion region) {
      this.region = region;
      this.executor = CompatibilitySingletonFactory.getInstance(MetricsExecutor.class).getExecutor();
      this.runnable = new HRegionMetricsWrapperRunnable();
      this.regionMetricsUpdateTask = this.executor.scheduleWithFixedDelay(this.runnable, PERIOD,
        PERIOD, TimeUnit.SECONDS);
    }
  
    @Override
    public String getTableName() {
      HTableDescriptor tableDesc = this.region.getTableDesc();
      if (tableDesc == null) {
        return UNKNOWN;
      }
      return tableDesc.getTableName().getQualifierAsString();
    }
  
    @Override
    public String getNamespace() {
      HTableDescriptor tableDesc = this.region.getTableDesc();
      if (tableDesc == null) {
        return UNKNOWN;
      }
      return tableDesc.getTableName().getNamespaceAsString();
    }
  
  
    @Override
    public String getRegionName() {
      HRegionInfo regionInfo = this.region.getRegionInfo();
      if (regionInfo == null) {
        return UNKNOWN;
      }
      return regionInfo.getEncodedName();
    }
  
    @Override
    public long getNumStores() {
      Map<byte[],Store> stores = this.region.stores;
      if (stores == null) {
        return 0;
      }
     return stores.size();
   }
 
   @Override
   public long getNumStoreFiles() {
     return numStoreFiles;
   }
 
   @Override
   public long getMemstoreSize() {
     return memstoreSize;
   }
 
   @Override
   public long getStoreFileSize() {
     return storeFileSize;
   }
 
   @Override
   public long getReadRequestCount() {
     return this.region.getReadRequestsCount();
   }
 
   @Override
   public long getWriteRequestCount() {
     return this.region.getWriteRequestsCount();
   }
 
   @Override
   public long getNumFilesCompacted() {
     return this.region.compactionNumFilesCompacted.get();
   }
 
   @Override
   public long getNumBytesCompacted() {
     return this.region.compactionNumBytesCompacted.get();
   }
 
   @Override
   public long getNumCompactionsCompleted() {
     return this.region.compactionsFinished.get();
   }
 
   @Override
   public long getLastMajorCompactionAge() {
     long lastMajorCompactionTs = 0L;
     try {
       lastMajorCompactionTs = this.region.getOldestHfileTs(true);
     } catch (IOException ioe) {
       LOG.error("Could not load HFile info ", ioe);
     }
     long now = EnvironmentEdgeManager.currentTime();
     return now - lastMajorCompactionTs;
   }
 
   @Override
   public long getNumCompactionsFailed() {
     return this.region.compactionsFailed.get();
   }
 
   @Override
   public long getMaxStoreFileAge() {
     return maxStoreFileAge;
   }
 
   @Override
   public long getMinStoreFileAge() {
     return minStoreFileAge;
   }
 
   @Override
   public long getAvgStoreFileAge() {
     return avgStoreFileAge;
   }
 
   @Override
   public long getNumReferenceFiles() {
     return numReferenceFiles;
   }
 
   @Override
   public int getRegionHashCode() {
     return this.region.hashCode();
   }
 
   public class HRegionMetricsWrapperRunnable implements Runnable {
 
     @Override
     public void run() {
       long tempNumStoreFiles = 0;
       long tempMemstoreSize = 0;
       long tempStoreFileSize = 0;
       long tempMaxStoreFileAge = 0;
       long tempMinStoreFileAge = Long.MAX_VALUE;
       long tempNumReferenceFiles = 0;
 
       long avgAgeNumerator = 0;
       long numHFiles = 0;
       if (region.stores != null) {
         for (Store store : region.stores.values()) {
           tempNumStoreFiles += store.getStorefilesCount();
           tempMemstoreSize += store.getMemStoreSize();
           tempStoreFileSize += store.getStorefilesSize();
 
           long storeMaxStoreFileAge = store.getMaxStoreFileAge();
           tempMaxStoreFileAge = (storeMaxStoreFileAge > tempMaxStoreFileAge) ?
             storeMaxStoreFileAge : tempMaxStoreFileAge;
 
           long storeMinStoreFileAge = store.getMinStoreFileAge();
           tempMinStoreFileAge = (storeMinStoreFileAge < tempMinStoreFileAge) ?
             storeMinStoreFileAge : tempMinStoreFileAge;
 
           long storeHFiles = store.getNumHFiles();
           avgAgeNumerator += store.getAvgStoreFileAge() * storeHFiles;
           numHFiles += storeHFiles;
           tempNumReferenceFiles += store.getNumReferenceFiles();
         }
       }
 
       numStoreFiles = tempNumStoreFiles;
       memstoreSize = tempMemstoreSize;
       storeFileSize = tempStoreFileSize;
       maxStoreFileAge = tempMaxStoreFileAge;
       if (tempMinStoreFileAge != Long.MAX_VALUE) {
         minStoreFileAge = tempMinStoreFileAge;
       }
 
       if (numHFiles != 0) {
         avgStoreFileAge = avgAgeNumerator / numHFiles;
       }
 
       numReferenceFiles = tempNumReferenceFiles;
     }
   }
 
   @Override
   public void close() throws IOException {
     regionMetricsUpdateTask.cancel(true);
   }
 
   /**
    * Get the replica id of this region.
    */
   @Override
   public int getReplicaId() {
     return region.getRegionInfo().getReplicaId();
   }
 
 }