/*
 * 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.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import org.apache.hadoop.hbase.CompatibilitySingletonFactory;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.metrics2.MetricsExecutor;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.hbase.thirdparty.com.google.common.collect.Sets;

@InterfaceAudience.Private
public class MetricsTableWrapperAggregateImpl implements MetricsTableWrapperAggregate, Closeable {
  private static final Logger LOG = LoggerFactory.getLogger(MetricsTableWrapperAggregateImpl.class);
  private final HRegionServer regionServer;
  private ScheduledExecutorService executor;
  private Runnable runnable;
  private long period;
  private ScheduledFuture<?> tableMetricsUpdateTask;
  private ConcurrentHashMap<TableName, MetricsTableValues> metricsTableMap =
    new ConcurrentHashMap<>();

  public MetricsTableWrapperAggregateImpl(final HRegionServer regionServer) {
    this.regionServer = regionServer;
    this.period = regionServer.getConfiguration().getLong(HConstants.REGIONSERVER_METRICS_PERIOD,
      HConstants.DEFAULT_REGIONSERVER_METRICS_PERIOD) + 1000;
    this.executor = CompatibilitySingletonFactory.getInstance(MetricsExecutor.class).getExecutor();
    this.runnable = new TableMetricsWrapperRunnable();
    this.tableMetricsUpdateTask =
      this.executor.scheduleWithFixedDelay(this.runnable, period, period, TimeUnit.MILLISECONDS);
  }

  public class TableMetricsWrapperRunnable implements Runnable {

    @Override
    public void run() {
      // The executor only reschedules this task (scheduleWithFixedDelay) if run() returns
      // normally. Any Throwable that escapes here (e.g. an NPE from a region closing mid-scan)
      // is swallowed by the underlying ScheduledFutureTask with no log output anywhere, and this
      // task permanently stops running. Catch everything so a failure is visible AND the next
      // scheduled run still happens.
      try {
        Map<TableName, MetricsTableValues> localMetricsTableMap = new HashMap<>();
        for (Region r : regionServer.getOnlineRegionsLocalContext()) {
          TableName tbl = r.getTableDescriptor().getTableName();
          MetricsTableValues mt = localMetricsTableMap.get(tbl);
          if (mt == null) {
            mt = new MetricsTableValues();
            localMetricsTableMap.put(tbl, mt);
          }
          long memstoreReadCount = 0L;
          long mixedReadCount = 0L;
          String tempKey = null;
          if (r.getStores() != null) {
            String familyName = null;
            for (Store store : r.getStores()) {
              familyName = store.getColumnFamilyName();

              mt.storeFileCount += store.getStorefilesCount();
              mt.maxStoreFileCount = Math.max(mt.maxStoreFileCount, store.getStorefilesCount());
              final MemStoreSize memstoreSize = store.getMemStoreSize();
              mt.memstoreSize += memstoreSize.getDataSize();
              mt.memstoreHeapSize += memstoreSize.getHeapSize();
              mt.memstoreOffHeapSize += memstoreSize.getOffHeapSize();
              mt.storeFileSize += store.getStorefilesSize();
              mt.referenceFileCount += store.getNumReferenceFiles();
              if (store.getMaxStoreFileAge().isPresent()) {
                mt.maxStoreFileAge =
                  Math.max(mt.maxStoreFileAge, store.getMaxStoreFileAge().getAsLong());
              }
              if (store.getMinStoreFileAge().isPresent()) {
                mt.minStoreFileAge =
                  Math.min(mt.minStoreFileAge, store.getMinStoreFileAge().getAsLong());
              }
              if (store.getAvgStoreFileAge().isPresent()) {
                mt.totalStoreFileAge +=
                  (long) (store.getAvgStoreFileAge().getAsDouble() * store.getStorefilesCount());
              }
              mt.storeCount += 1;

              mt.staticIndexSize += store.getTotalStaticIndexSize();
              mt.staticBloomSize += store.getTotalStaticBloomSize();

              mt.bloomRequestsCount += store.getBloomFilterRequestsCount();
              mt.bloomNegativeResultsCount += store.getBloomFilterNegativeResultsCount();
              mt.bloomEligibleRequestsCount += store.getBloomFilterEligibleRequestsCount();

              tempKey = tbl.getNameAsString() + HASH + familyName;
              Long tempVal = mt.perStoreMemstoreOnlyReadCount.get(tempKey);
              if (tempVal == null) {
                tempVal = 0L;
              }
              memstoreReadCount = store.getMemstoreOnlyRowReadsCount() + tempVal;
              tempVal = mt.perStoreMixedReadCount.get(tempKey);
              if (tempVal == null) {
                tempVal = 0L;
              }
              mixedReadCount = store.getMixedRowReadsCount() + tempVal;
              // accumulate the count
              mt.perStoreMemstoreOnlyReadCount.put(tempKey, memstoreReadCount);
              mt.perStoreMixedReadCount.put(tempKey, mixedReadCount);
              mt.perStoreFileSize.merge(tempKey, store.getStorefilesSize(), Long::sum);
            }

            mt.regionCount += 1;

            mt.readRequestCount += r.getReadRequestsCount();
            mt.filteredReadRequestCount += r.getFilteredReadRequestsCount();
            mt.writeRequestCount += r.getWriteRequestsCount();
          }
        }

        for (Map.Entry<TableName, MetricsTableValues> entry : localMetricsTableMap.entrySet()) {
          TableName tbl = entry.getKey();
          if (metricsTableMap.get(tbl) == null) {
            // this will add the Wrapper to the list of TableMetrics
            CompatibilitySingletonFactory.getInstance(MetricsRegionServerSourceFactory.class)
              .getTableAggregate()
              .getOrCreateTableSource(tbl.getNameAsString(), MetricsTableWrapperAggregateImpl.this);
          }
          metricsTableMap.put(entry.getKey(), entry.getValue());
        }
        Set<TableName> existingTableNames = Sets.newHashSet(metricsTableMap.keySet());
        existingTableNames.removeAll(localMetricsTableMap.keySet());
        MetricsTableAggregateSource agg = CompatibilitySingletonFactory
          .getInstance(MetricsRegionServerSourceFactory.class).getTableAggregate();
        for (TableName table : existingTableNames) {
          agg.deleteTableSource(table.getNameAsString());
          if (metricsTableMap.get(table) != null) {
            metricsTableMap.remove(table);
          }
        }
      } catch (Throwable t) {
        LOG.error("Failed to compute per-table metrics; will retry on next scheduled run", t);
      }
    }
  }

  @Override
  public long getReadRequestCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    } else {
      return metricsTable.readRequestCount;
    }
  }

  @Override
  public Map<String, Long> getMemstoreOnlyRowReadsCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return null;
    } else {
      return metricsTable.perStoreMemstoreOnlyReadCount;
    }
  }

  @Override
  public Map<String, Long> getMixedRowReadsCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return null;
    } else {
      return metricsTable.perStoreMixedReadCount;
    }
  }

  @Override
  public Map<String, Long> getStoreFileSizePerStore(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return null;
    } else {
      return metricsTable.perStoreFileSize;
    }
  }

  @Override
  public long getCpRequestsCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    } else {
      return metricsTable.cpRequestCount;
    }
  }

  public long getFilteredReadRequestCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }
    return metricsTable.filteredReadRequestCount;
  }

  @Override
  public long getWriteRequestCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    } else {
      return metricsTable.writeRequestCount;
    }
  }

  @Override
  public long getTotalRequestsCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    } else {
      return metricsTable.readRequestCount + metricsTable.writeRequestCount;
    }
  }

  @Override
  public long getMemStoreSize(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    } else {
      return metricsTable.memstoreSize;
    }
  }

  @Override
  public long getMemStoreHeapSize(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    } else {
      return metricsTable.memstoreHeapSize;
    }
  }

  @Override
  public long getMemStoreOffHeapSize(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    } else {
      return metricsTable.memstoreOffHeapSize;
    }
  }

  @Override
  public long getStoreFileSize(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    } else {
      return metricsTable.storeFileSize;
    }
  }

  @Override
  public long getTableSize(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    } else {
      return metricsTable.memstoreSize + metricsTable.storeFileSize;
    }
  }

  public long getNumRegions(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }
    return metricsTable.regionCount;
  }

  @Override
  public long getNumStores(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }
    return metricsTable.storeCount;
  }

  @Override
  public long getNumStoreFiles(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }
    return metricsTable.storeFileCount;
  }

  @Override
  public long getMaxStoreFiles(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }
    return metricsTable.maxStoreFileCount;
  }

  @Override
  public long getMaxStoreFileAge(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }
    return metricsTable.maxStoreFileAge;
  }

  @Override
  public long getMinStoreFileAge(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }
    return metricsTable.minStoreFileAge == Long.MAX_VALUE ? 0 : metricsTable.minStoreFileAge;
  }

  @Override
  public long getAvgStoreFileAge(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }

    return metricsTable.storeFileCount == 0
      ? 0
      : (metricsTable.totalStoreFileAge / metricsTable.storeFileCount);
  }

  @Override
  public long getStaticIndexSize(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }

    return metricsTable.staticIndexSize;
  }

  @Override
  public long getStaticBloomSize(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }

    return metricsTable.staticBloomSize;
  }

  @Override
  public long getBloomFilterRequestsCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }

    return metricsTable.bloomRequestsCount;
  }

  @Override
  public long getBloomFilterNegativeResultsCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }

    return metricsTable.bloomNegativeResultsCount;
  }

  @Override
  public long getBloomFilterEligibleRequestsCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }

    return metricsTable.bloomEligibleRequestsCount;
  }

  @Override
  public long getNumReferenceFiles(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }
    return metricsTable.referenceFileCount;
  }

  @Override
  public long getAvgRegionSize(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }
    return metricsTable.regionCount == 0
      ? 0
      : (metricsTable.memstoreSize + metricsTable.storeFileSize) / metricsTable.regionCount;
  }

  public long getCpRequestCount(String table) {
    MetricsTableValues metricsTable = metricsTableMap.get(TableName.valueOf(table));
    if (metricsTable == null) {
      return 0;
    }
    return metricsTable.cpRequestCount;
  }

  @Override
  public void close() throws IOException {
    tableMetricsUpdateTask.cancel(true);
  }

  private static class MetricsTableValues {
    long readRequestCount;
    long filteredReadRequestCount;
    long writeRequestCount;
    long memstoreSize;
    long memstoreHeapSize;
    long memstoreOffHeapSize;
    long regionCount;
    long storeCount;
    long storeFileCount;
    long maxStoreFileCount;
    long storeFileSize;
    long maxStoreFileAge;
    long minStoreFileAge = Long.MAX_VALUE;
    long totalStoreFileAge;

    long staticIndexSize;

    long staticBloomSize;
    long referenceFileCount;

    long bloomRequestsCount;
    long bloomNegativeResultsCount;
    long bloomEligibleRequestsCount;
    long cpRequestCount;
    Map<String, Long> perStoreMemstoreOnlyReadCount = new HashMap<>();
    Map<String, Long> perStoreMixedReadCount = new HashMap<>();
    Map<String, Long> perStoreFileSize = new HashMap<>();
  }

}