/*
    * 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.IOException;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.CompatibilitySingletonFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.ipc.RpcServer;
  import org.apache.hadoop.hbase.security.User;
  import org.apache.hadoop.hbase.security.UserProvider;
  import org.apache.hadoop.hbase.util.LossyCounting;
  
  @InterfaceAudience.Private
  public class MetricsUserAggregateImpl implements MetricsUserAggregate{
  
    /** Provider for mapping principal names to Users */
    private final UserProvider userProvider;
  
    private final MetricsUserAggregateSource source;
    private final LossyCounting<MetricsUserSource> userMetricLossyCounting;
  
    public MetricsUserAggregateImpl(Configuration conf) {
      source = CompatibilitySingletonFactory.getInstance(MetricsRegionServerSourceFactory.class)
          .getUserAggregate();
      userMetricLossyCounting = new LossyCounting<>("userMetrics", conf,
        new LossyCounting.LossyCountingListener<MetricsUserSource>() {
          @Override
          public void sweep(MetricsUserSource key) {
            source.deregister(key);
          }
        });
      this.userProvider = UserProvider.instantiate(conf);
    }
  
    /**
     * Returns the active user to which authorization checks should be applied.
     * If we are in the context of an RPC call, the remote user is used,
     * otherwise the currently logged in user is used.
     */
    private String getActiveUser() {
      User user = RpcServer.getRequestUser();
      if (user == null) {
        try {
          user = userProvider.getCurrent();
        } catch (IOException e) { }
      }
      return user != null ? user.getShortName() : null;
    }
  
    MetricsUserAggregateSource getSource() {
      return source;
    }
  
    @Override
    public void updatePut(long t) {
      String user = getActiveUser();
      if (user != null) {
        getOrCreateMetricsUser(user).updatePut(t);
      }
    }
  
    @Override
    public void updateDelete(long t) {
      String user = getActiveUser();
      if (user != null) {
        getOrCreateMetricsUser(user).updateDelete(t);
      }
    }
  
    @Override
    public void updateGet(long t) {
      String user = getActiveUser();
      if (user != null) {
        getOrCreateMetricsUser(user).updateGet(t);
      }
    }
  
    @Override
    public void updateIncrement(long t) {
      String user = getActiveUser();
      if (user != null) {
        getOrCreateMetricsUser(user).updateIncrement(t);
     }
   }
 
   @Override
   public void updateAppend(long t) {
     String user = getActiveUser();
     if (user != null) {
       getOrCreateMetricsUser(user).updateAppend(t);
     }
   }
 
   @Override
   public void updateReplay(long t) {
     String user = getActiveUser();
     if (user != null) {
       getOrCreateMetricsUser(user).updateReplay(t);
     }
   }
 
   @Override
   public void updateScanTime(long t) {
     String user = getActiveUser();
     if (user != null) {
       getOrCreateMetricsUser(user).updateScanTime(t);
     }
   }
 
   private MetricsUserSource getOrCreateMetricsUser(String user) {
     MetricsUserSource userSource = source.getOrCreateMetricsUser(user);
     userMetricLossyCounting.add(userSource);
     return userSource;
   }
 }