/*
 * 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.OptionalDouble;
import java.util.OptionalLong;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import org.apache.commons.lang3.mutable.MutableLong;
import org.apache.hadoop.hbase.CompatibilitySingletonFactory;
import org.apache.hadoop.hbase.client.RegionInfo;
import org.apache.hadoop.hbase.client.TableDescriptor;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
import org.apache.hadoop.hbase.util.Pair;
import org.apache.hadoop.metrics2.MetricsExecutor;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@InterfaceAudience.Private
public class MetricsRegionWrapperImpl implements MetricsRegionWrapper, Closeable {

  private static final Logger LOG = LoggerFactory.getLogger(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 storeRefCount;
  private long maxCompactedStoreFileRefCount;
  private long memstoreSize;
  private long memstoreHeapSize;
  private long memstoreOffHeapSize;
  private long storeFileSize;
  private long maxStoreFileAge;
  private long minStoreFileAge;
  private long avgStoreFileAge;
  private long numReferenceFiles;
  private long maxFlushQueueSize;
  private long maxCompactionQueueSize;
  private Map<String, Long> readsOnlyFromMemstore;
  private Map<String, Long> mixedReadsOnStore;

  private ScheduledFuture<?> regionMetricsUpdateTask;

  private float currentRegionCacheRatio;
  private final String tableDescriptorHash;

  private float currentRegionColdDataRatio;

  public MetricsRegionWrapperImpl(HRegion region) {
    this.region = region;
    this.tableDescriptorHash = determineTableDescriptorHash();
    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() {
    TableDescriptor tableDesc = this.region.getTableDescriptor();
    if (tableDesc == null) {
      return UNKNOWN;
    }
    return tableDesc.getTableName().getQualifierAsString();
  }

  @Override
  public String getNamespace() {
    TableDescriptor tableDesc = this.region.getTableDescriptor();
    if (tableDesc == null) {
      return UNKNOWN;
    }
    return tableDesc.getTableName().getNamespaceAsString();
  }

  @Override
  public String getRegionName() {
    RegionInfo regionInfo = this.region.getRegionInfo();
    if (regionInfo == null) {
      return UNKNOWN;
    }
    return regionInfo.getEncodedName();
  }

  @Override
  public long getNumStores() {
    Map<byte[], HStore> 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 getMemStoreHeapSize() {
    return memstoreHeapSize;
  }

  @Override
  public long getMemStoreOffHeapSize() {
    return memstoreOffHeapSize;
  }

  @Override
  public long getStoreFileSize() {
    return storeFileSize;
  }

  public float getCurrentRegionCacheRatio() {
    return currentRegionCacheRatio;
  }

  public float getCurrentRegionColdDataRatio() {
    return currentRegionColdDataRatio;
  }

  @Override
  public long getStoreRefCount() {
    return storeRefCount;
  }

  @Override
  public long getMaxCompactedStoreFileRefCount() {
    return maxCompactedStoreFileRefCount;
  }

  @Override
  public long getReadRequestCount() {
    return this.region.getReadRequestsCount();
  }

  @Override
  public long getCpRequestCount() {
    return this.region.getCpRequestsCount();
  }

  @Override
  public long getFilteredReadRequestCount() {
    return this.region.getFilteredReadRequestsCount();
  }

  @Override
  public long getWriteRequestCount() {
    return this.region.getWriteRequestsCount();
  }

  @Override
  public long getNumFilesCompacted() {
    return this.region.compactionNumFilesCompacted.sum();
  }

  @Override
  public long getNumBytesCompacted() {
    return this.region.compactionNumBytesCompacted.sum();
  }

  @Override
  public long getNumCompactionsCompleted() {
    return this.region.compactionsFinished.sum();
  }

  @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 getTotalRequestCount() {
    return getReadRequestCount() + getWriteRequestCount();
  }

  @Override
  public long getNumCompactionsFailed() {
    return this.region.compactionsFailed.sum();
  }

  @Override
  public long getNumCompactionsQueued() {
    return this.region.compactionsQueued.sum();
  }

  @Override
  public long getNumFlushesQueued() {
    return this.region.flushesQueued.sum();
  }

  @Override
  public long getMaxCompactionQueueSize() {
    return maxCompactionQueueSize;
  }

  @Override
  public long getMaxFlushQueueSize() {
    return maxFlushQueueSize;
  }

  @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();
  }

  @Override
  public Map<String, Long> getMemstoreOnlyRowReadsCount() {
    return readsOnlyFromMemstore;
  }

  @Override
  public Map<String, Long> getMixedRowReadsCount() {
    return mixedReadsOnStore;
  }

  public class HRegionMetricsWrapperRunnable 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 {
        long tempNumStoreFiles = 0;
        int tempStoreRefCount = 0;
        int tempMaxCompactedStoreFileRefCount = 0;
        long tempMemstoreSize = 0;
        long tempMemstoreHeapSize = 0;
        long tempMemstoreOffHeapSize = 0;
        long tempStoreFileSize = 0;
        long tempMaxStoreFileAge = 0;
        long tempMinStoreFileAge = Long.MAX_VALUE;
        long tempNumReferenceFiles = 0;
        long tempMaxCompactionQueueSize = 0;
        long tempMaxFlushQueueSize = 0;
        long avgAgeNumerator = 0;
        long numHFiles = 0;
        if (region.stores != null) {
          for (HStore store : region.stores.values()) {
            tempNumStoreFiles += store.getStorefilesCount();
            int currentStoreRefCount = store.getStoreRefCount();
            tempStoreRefCount += currentStoreRefCount;
            int currentMaxCompactedStoreFileRefCount = store.getMaxCompactedStoreFileRefCount();
            tempMaxCompactedStoreFileRefCount =
              Math.max(tempMaxCompactedStoreFileRefCount, currentMaxCompactedStoreFileRefCount);
            final MemStoreSize memStore = store.getMemStoreSize();
            tempMemstoreSize += memStore.getDataSize();
            tempMemstoreHeapSize += memStore.getHeapSize();
            tempMemstoreOffHeapSize += memStore.getOffHeapSize();
            tempStoreFileSize += store.getStorefilesSize();
            OptionalLong storeMaxStoreFileAge = store.getMaxStoreFileAge();
            if (
              storeMaxStoreFileAge.isPresent()
                && storeMaxStoreFileAge.getAsLong() > tempMaxStoreFileAge
            ) {
              tempMaxStoreFileAge = storeMaxStoreFileAge.getAsLong();
            }

            OptionalLong storeMinStoreFileAge = store.getMinStoreFileAge();
            if (
              storeMinStoreFileAge.isPresent()
                && storeMinStoreFileAge.getAsLong() < tempMinStoreFileAge
            ) {
              tempMinStoreFileAge = storeMinStoreFileAge.getAsLong();
            }

            long storeHFiles = store.getNumHFiles();
            numHFiles += storeHFiles;
            tempNumReferenceFiles += store.getNumReferenceFiles();

            OptionalDouble storeAvgStoreFileAge = store.getAvgStoreFileAge();
            if (storeAvgStoreFileAge.isPresent()) {
              avgAgeNumerator += (long) storeAvgStoreFileAge.getAsDouble() * storeHFiles;
            }
            if (mixedReadsOnStore == null) {
              mixedReadsOnStore = new HashMap<String, Long>();
            }
            Long tempVal = mixedReadsOnStore.get(store.getColumnFamilyName());
            if (tempVal == null) {
              tempVal = 0L;
            } else {
              tempVal += store.getMixedRowReadsCount();
            }
            mixedReadsOnStore.put(store.getColumnFamilyName(), tempVal);
            if (readsOnlyFromMemstore == null) {
              readsOnlyFromMemstore = new HashMap<String, Long>();
            }
            tempVal = readsOnlyFromMemstore.get(store.getColumnFamilyName());
            if (tempVal == null) {
              tempVal = 0L;
            } else {
              tempVal += store.getMemstoreOnlyRowReadsCount();
            }
            readsOnlyFromMemstore.put(store.getColumnFamilyName(), tempVal);
          }
        }
        MutableLong regionCachedAmount = new MutableLong(0);
        region.getBlockCache().getRegionCachedInfo()
          .ifPresent(regionCacheRatio -> regionCachedAmount
            .addAndGet(regionCacheRatio.getOrDefault(region.getRegionInfo().getEncodedName(), 0L)));
        if (tempStoreFileSize > 0) {
          LOG.debug("Region {}, had cached {} bytes from a total of {}",
            region.getRegionInfo().getEncodedName(), regionCachedAmount.getValue(),
            tempStoreFileSize);
          currentRegionCacheRatio = regionCachedAmount.floatValue() / tempStoreFileSize;
          if (DataTieringManager.getInstance() != null) {
            currentRegionColdDataRatio = DataTieringManager.getInstance().getRegionColdDataSize()
              .getOrDefault(region.getRegionInfo().getEncodedName(), new Pair<>(null, 0L))
              .getSecond() / (float) tempStoreFileSize;
          }
        }
        numStoreFiles = tempNumStoreFiles;
        storeRefCount = tempStoreRefCount;
        maxCompactedStoreFileRefCount = tempMaxCompactedStoreFileRefCount;
        memstoreSize = tempMemstoreSize;
        memstoreHeapSize = tempMemstoreHeapSize;
        memstoreOffHeapSize = tempMemstoreOffHeapSize;
        storeFileSize = tempStoreFileSize;
        maxStoreFileAge = tempMaxStoreFileAge;
        if (tempMinStoreFileAge != Long.MAX_VALUE) {
          minStoreFileAge = tempMinStoreFileAge;
        }

        if (numHFiles != 0) {
          avgStoreFileAge = avgAgeNumerator / numHFiles;
        }

        numReferenceFiles = tempNumReferenceFiles;
        tempMaxCompactionQueueSize = getNumCompactionsQueued();
        tempMaxFlushQueueSize = getNumFlushesQueued();
        if (tempMaxCompactionQueueSize > maxCompactionQueueSize) {
          maxCompactionQueueSize = tempMaxCompactionQueueSize;
        }
        if (tempMaxFlushQueueSize > maxFlushQueueSize) {
          maxFlushQueueSize = tempMaxFlushQueueSize;
        }
      } catch (Throwable t) {
        LOG.error("Failed to compute per-region metrics; will retry on next scheduled run", t);
      }
    }
  }

  @Override
  public String getTableDescriptorHash() {
    return tableDescriptorHash;
  }

  private String determineTableDescriptorHash() {
    TableDescriptor tableDesc = this.region.getTableDescriptor();
    if (tableDesc == null) {
      return UNKNOWN;
    }
    return tableDesc.getDescriptorHash();
  }

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

  /**
   * Get the replica id of this region.
   */
  @Override
  public int getReplicaId() {
    return region.getRegionInfo().getReplicaId();
  }

}