/**
    * 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.hbtop.mode;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import org.apache.hadoop.hbase.ClusterStatus;
  import org.apache.hadoop.hbase.ServerLoad;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.hbtop.Record;
  import org.apache.hadoop.hbase.hbtop.RecordFilter;
  import org.apache.hadoop.hbase.hbtop.field.Field;
  import org.apache.hadoop.hbase.hbtop.field.FieldInfo;
  import org.apache.hadoop.hbase.hbtop.field.Size;
  import org.apache.hadoop.hbase.hbtop.field.Size.Unit;
  
  /**
   * Implementation for {@link ModeStrategy} for RegionServer Mode.
   */
  @InterfaceAudience.Private
  public final class RegionServerModeStrategy implements ModeStrategy {
  
    private final List<FieldInfo> fieldInfos = Arrays.asList(
      new FieldInfo(Field.REGION_SERVER, 0, true),
      new FieldInfo(Field.LONG_REGION_SERVER, 0, false),
      new FieldInfo(Field.REGION_COUNT, 7, true),
      new FieldInfo(Field.REQUEST_COUNT_PER_SECOND, 10, true),
      new FieldInfo(Field.READ_REQUEST_COUNT_PER_SECOND, 10, true),
      new FieldInfo(Field.WRITE_REQUEST_COUNT_PER_SECOND, 10, true),
      new FieldInfo(Field.STORE_FILE_SIZE, 13, true),
      new FieldInfo(Field.UNCOMPRESSED_STORE_FILE_SIZE, 15, false),
      new FieldInfo(Field.NUM_STORE_FILES, 7, true),
      new FieldInfo(Field.MEM_STORE_SIZE, 11, true),
      new FieldInfo(Field.USED_HEAP_SIZE, 11, true),
      new FieldInfo(Field.MAX_HEAP_SIZE, 11, true)
    );
  
    private final RegionModeStrategy regionModeStrategy = new RegionModeStrategy();
  
    RegionServerModeStrategy(){
    }
  
    @Override
    public List<FieldInfo> getFieldInfos() {
      return fieldInfos;
    }
  
    @Override
    public Field getDefaultSortField() {
      return Field.REQUEST_COUNT_PER_SECOND;
    }
  
    @Override
    public List<Record> getRecords(ClusterStatus clusterStatus) {
      // Get records from RegionModeStrategy and add REGION_COUNT field
      List<Record> records = new ArrayList<>();
      for (Record record : regionModeStrategy.getRecords(clusterStatus)) {
        List<Record.Entry> entries = new ArrayList<>();
        for (FieldInfo fieldInfo : fieldInfos) {
          if (record.containsKey(fieldInfo.getField())) {
            entries.add(Record.entry(fieldInfo.getField(),
              record.get(fieldInfo.getField())));
          }
        }
  
        // Add REGION_COUNT field
        records.add(Record.builder().putAll(Record.ofEntries(entries))
          .put(Field.REGION_COUNT, 1).build());
      }
  
      // Aggregation by NAMESPACE field
      Map<String, Record> retMap = new HashMap<>();
      for (Record record : records) {
        String regionServer = record.get(Field.LONG_REGION_SERVER).asString();
        if (retMap.containsKey(regionServer)) {
          retMap.put(regionServer, retMap.get(regionServer).combine(record));
        } else {
          retMap.put(regionServer, record);
        }
     }
 
     // Add USED_HEAP_SIZE field and MAX_HEAP_SIZE field
     for (ServerName sn : clusterStatus.getServers()) {
       Record record = retMap.get(sn.getServerName());
       if (record == null) {
         continue;
       }
       ServerLoad sl = clusterStatus.getLoad(sn);
       Record newRecord = Record.builder().putAll(record)
         .put(Field.USED_HEAP_SIZE, new Size(sl.getUsedHeapMB(), Unit.MEGABYTE))
         .put(Field.MAX_HEAP_SIZE, new Size(sl.getMaxHeapMB(), Unit.MEGABYTE)).build();
       retMap.put(sn.getServerName(), newRecord);
     }
     return new ArrayList<>(retMap.values());
   }
 
   @Override
   public DrillDownInfo drillDown(Record selectedRecord) {
     List<RecordFilter> initialFilters = Collections.singletonList(RecordFilter
       .newBuilder(Field.REGION_SERVER)
       .doubleEquals(selectedRecord.get(Field.REGION_SERVER)));
     return new DrillDownInfo(Mode.REGION, initialFilters);
   }
 }