/*
 * 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 java.net.InetAddress;
import java.util.Optional;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.CompatibilitySingletonFactory;
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;
import org.apache.yetus.audience.InterfaceAudience;

@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, source::deregister);
    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() {
    Optional<User> user = RpcServer.getRequestUser();
    if (!user.isPresent()) {
      // for non-rpc handling, fallback to system user
      try {
        user = Optional.of(userProvider.getCurrent());
      } catch (IOException ignore) {
      }
    }
    return user.map(User::getShortName).orElse(null);
  }

  @Override
  public MetricsUserAggregateSource getSource() {
    return source;
  }

  @Override
  public void updatePut(long t) {
    String user = getActiveUser();
    if (user != null) {
      MetricsUserSource userSource = getOrCreateMetricsUser(user);
      userSource.updatePut(t);
      incrementClientWriteMetrics(userSource);
    }

  }

  private String getClient() {
    Optional<InetAddress> ipOptional = RpcServer.getRemoteAddress();
    return ipOptional.map(InetAddress::getHostName).orElse(null);
  }

  private void incrementClientReadMetrics(MetricsUserSource userSource) {
    String client = getClient();
    if (client != null && userSource != null) {
      userSource.getOrCreateMetricsClient(client).incrementReadRequest();
    }
  }

  private void incrementFilteredReadRequests(MetricsUserSource userSource) {
    String client = getClient();
    if (client != null && userSource != null) {
      userSource.getOrCreateMetricsClient(client).incrementFilteredReadRequests();
    }
  }

  private void incrementClientWriteMetrics(MetricsUserSource userSource) {
    String client = getClient();
    if (client != null && userSource != null) {
      userSource.getOrCreateMetricsClient(client).incrementWriteRequest();
    }
  }

  @Override
  public void updateDelete(long t) {
    String user = getActiveUser();
    if (user != null) {
      MetricsUserSource userSource = getOrCreateMetricsUser(user);
      userSource.updateDelete(t);
      incrementClientWriteMetrics(userSource);
    }
  }

  @Override
  public void updateGet(long t) {
    String user = getActiveUser();
    if (user != null) {
      MetricsUserSource userSource = getOrCreateMetricsUser(user);
      userSource.updateGet(t);
    }
  }

  @Override
  public void updateIncrement(long t) {
    String user = getActiveUser();
    if (user != null) {
      MetricsUserSource userSource = getOrCreateMetricsUser(user);
      userSource.updateIncrement(t);
      incrementClientWriteMetrics(userSource);
    }
  }

  @Override
  public void updateAppend(long t) {
    String user = getActiveUser();
    if (user != null) {
      MetricsUserSource userSource = getOrCreateMetricsUser(user);
      userSource.updateAppend(t);
      incrementClientWriteMetrics(userSource);
    }
  }

  @Override
  public void updateReplay(long t) {
    String user = getActiveUser();
    if (user != null) {
      MetricsUserSource userSource = getOrCreateMetricsUser(user);
      userSource.updateReplay(t);
      incrementClientWriteMetrics(userSource);
    }
  }

  @Override
  public void updateScanTime(long t) {
    String user = getActiveUser();
    if (user != null) {
      MetricsUserSource userSource = getOrCreateMetricsUser(user);
      userSource.updateScanTime(t);
    }
  }

  @Override
  public void updateFilteredReadRequests() {
    String user = getActiveUser();
    if (user != null) {
      MetricsUserSource userSource = getOrCreateMetricsUser(user);
      incrementFilteredReadRequests(userSource);
    }
  }

  @Override
  public void updateReadRequestCount() {
    String user = getActiveUser();
    if (user != null) {
      MetricsUserSource userSource = getOrCreateMetricsUser(user);
      incrementClientReadMetrics(userSource);
    }
  }

  private MetricsUserSource getOrCreateMetricsUser(String user) {
    MetricsUserSource userSource = source.getOrCreateMetricsUser(user);
    userMetricLossyCounting.add(userSource);
    return userSource;
  }
}