/*
 * 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.geode.cache.query.cq.internal;

import org.apache.logging.log4j.Logger;

import org.apache.geode.StatisticDescriptor;
import org.apache.geode.Statistics;
import org.apache.geode.StatisticsFactory;
import org.apache.geode.StatisticsType;
import org.apache.geode.StatisticsTypeFactory;
import org.apache.geode.cache.query.CqException;
import org.apache.geode.cache.query.CqQuery;
import org.apache.geode.cache.query.internal.DefaultQueryService;
import org.apache.geode.cache.query.internal.cq.CqService;
import org.apache.geode.internal.NanoTimer;
import org.apache.geode.internal.cache.FilterProfile;
import org.apache.geode.internal.cache.InternalCache;
import org.apache.geode.internal.logging.LogService;
import org.apache.geode.internal.statistics.StatisticsTypeFactoryImpl;

/**
 * This class tracks GemFire statistics related to CqService. Specifically the following statistics
 * are tracked: Number of CQs created Number of active CQs Number of CQs suspended or stopped Number
 * of CQs closed Number of CQs on a client
 *
 * @since GemFire 5.5
 */
public class CqServiceVsdStats {
  private static final Logger logger = LogService.getLogger();

  /** The <code>StatisticsType</code> of the statistics */
  private static final StatisticsType _type;

  /** Name of the created CQs statistic */
  private static final String CQS_CREATED = "numCqsCreated";

  /** Name of the active CQs statistic */
  private static final String CQS_ACTIVE = "numCqsActive";

  /** Name of the stopped CQs statistic */
  private static final String CQS_STOPPED = "numCqsStopped";

  /** Name of the closed CQs statistic */
  private static final String CQS_CLOSED = "numCqsClosed";

  /** Name of the client's CQs statistic */
  private static final String CQS_ON_CLIENT = "numCqsOnClient";

  /** Number of clients with CQs statistic */
  private static final String CLIENTS_WITH_CQS = "numClientsWithCqs";

  /** CQ query execution time. */
  private static final String CQ_QUERY_EXECUTION_TIME = "cqQueryExecutionTime";

  /** CQ query execution in progress */
  private static final String CQ_QUERY_EXECUTION_IN_PROGRESS = "cqQueryExecutionInProgress";

  /** Completed CQ query executions */
  private static final String CQ_QUERY_EXECUTIONS_COMPLETED = "cqQueryExecutionsCompleted";

  /** Unique CQs, number of different CQ queries */
  private static final String UNIQUE_CQ_QUERY = "numUniqueCqQuery";

  /** Id of the CQs created statistic */
  private static final int _numCqsCreatedId;

  /** Id of the active CQs statistic */
  private static final int _numCqsActiveId;

  /** Id of the stopped CQs statistic */
  private static final int _numCqsStoppedId;

  /** Id of the closed CQs statistic */
  private static final int _numCqsClosedId;

  /** Id of the CQs on client statistic */
  private static final int _numCqsOnClientId;

  /** Id of the Clients with Cqs statistic */
  private static final int _numClientsWithCqsId;

  /** Id for the CQ query execution time. */
  private static final int _cqQueryExecutionTimeId;

  /** Id for the CQ query execution in progress */
  private static final int _cqQueryExecutionInProgressId;

  /** Id for completed CQ query executions */
  private static final int _cqQueryExecutionsCompletedId;

  /** Id for unique CQs, difference in CQ queries */
  private static final int _numUniqueCqQuery;

  /*
   * Static initializer to create and initialize the <code>StatisticsType</code>
   */
  static {
    String statName = "CqServiceStats";
    StatisticsTypeFactory f = StatisticsTypeFactoryImpl.singleton();

    _type = f.createType(statName, statName,
        new StatisticDescriptor[] {
            f.createLongCounter(CQS_CREATED, "Number of CQs created.", "operations"),
            f.createLongCounter(CQS_ACTIVE, "Number of CQS actively executing.", "operations"),
            f.createLongCounter(CQS_STOPPED, "Number of CQs stopped.", "operations"),
            f.createLongCounter(CQS_CLOSED, "Number of CQs closed.", "operations"),
            f.createLongCounter(CQS_ON_CLIENT, "Number of CQs on the client.", "operations"),
            f.createLongCounter(CLIENTS_WITH_CQS, "Number of Clients with CQs.", "operations"),
            f.createLongCounter(CQ_QUERY_EXECUTION_TIME, "Time taken for CQ Query Execution.",
                "nanoseconds"),
            f.createLongCounter(CQ_QUERY_EXECUTIONS_COMPLETED, "Number of CQ Query Executions.",
                "operations"),
            f.createIntGauge(CQ_QUERY_EXECUTION_IN_PROGRESS, "CQ Query Execution In Progress.",
                "operations"),
            f.createIntGauge(UNIQUE_CQ_QUERY, "Number of Unique CQ Querys.", "Queries"),

        });

    // Initialize id fields
    _numCqsCreatedId = _type.nameToId(CQS_CREATED);
    _numCqsActiveId = _type.nameToId(CQS_ACTIVE);
    _numCqsStoppedId = _type.nameToId(CQS_STOPPED);
    _numCqsClosedId = _type.nameToId(CQS_CLOSED);
    _numCqsOnClientId = _type.nameToId(CQS_ON_CLIENT);
    _numClientsWithCqsId = _type.nameToId(CLIENTS_WITH_CQS);
    _cqQueryExecutionTimeId = _type.nameToId(CQ_QUERY_EXECUTION_TIME);
    _cqQueryExecutionsCompletedId = _type.nameToId(CQ_QUERY_EXECUTIONS_COMPLETED);
    _cqQueryExecutionInProgressId = _type.nameToId(CQ_QUERY_EXECUTION_IN_PROGRESS);
    _numUniqueCqQuery = _type.nameToId(UNIQUE_CQ_QUERY);
  }

  /** The <code>Statistics</code> instance to which most behavior is delegated */
  private final Statistics _stats;

  /**
   * Constructor.
   *
   * @param factory The <code>StatisticsFactory</code> which creates the <code>Statistics</code>
   *        instance
   */
  CqServiceVsdStats(StatisticsFactory factory) {
    this._stats = factory.createAtomicStatistics(_type, "CqServiceStats");
  }

  /**
   * Closes the <code>HARegionQueueStats</code>.
   */
  public void close() {
    this._stats.close();
  }

  /**
   * Returns the current value of the "numCqsCreated" stat.
   *
   * @return the current value of the "numCqsCreated" stat
   */
  long getNumCqsCreated() {
    return this._stats.getLong(_numCqsCreatedId);
  }

  /**
   * Increments the "numCqsCreated" stat by 1.
   */
  void incCqsCreated() {
    this._stats.incLong(_numCqsCreatedId, 1);
  }

  /**
   * Returns the current value of the "numCqsActive" stat.
   *
   * @return the current value of the "numCqsActive" stat
   */
  long getNumCqsActive() {
    return this._stats.getLong(_numCqsActiveId);
  }

  /**
   * Increments the "numCqsActive" stat by 1.
   */
  void incCqsActive() {
    this._stats.incLong(_numCqsActiveId, 1);
  }

  /**
   * Decrements the "numCqsActive" stat by 1.
   */
  void decCqsActive() {
    this._stats.incLong(_numCqsActiveId, -1);
  }

  /**
   * Returns the current value of the "numCqsStopped" stat.
   *
   * @return the current value of the "numCqsStopped" stat
   */
  long getNumCqsStopped() {
    return this._stats.getLong(_numCqsStoppedId);
  }

  /**
   * Increments the "numCqsStopped" stat by 1.
   */
  void incCqsStopped() {
    this._stats.incLong(_numCqsStoppedId, 1);
  }

  /**
   * Decrements the "numCqsStopped" stat by 1.
   */
  void decCqsStopped() {
    this._stats.incLong(_numCqsStoppedId, -1);
  }

  /**
   * Returns the current value of the "numCqsClosed" stat.
   *
   * @return the current value of the "numCqsClosed" stat
   */
  long getNumCqsClosed() {
    return this._stats.getLong(_numCqsClosedId);
  }

  /**
   * Increments the "numCqsClosed" stat by 1.
   */
  void incCqsClosed() {
    this._stats.incLong(_numCqsClosedId, 1);
  }

  /**
   * Returns the current value of the "numCqsOnClient" stat.
   *
   * @return the current value of the "numCqsOnClient" stat
   */
  long getNumCqsOnClient() {
    return this._stats.getLong(_numCqsOnClientId);
  }

  /**
   * Increments the "numCqsOnClient" stat by 1.
   */
  void incCqsOnClient() {
    this._stats.incLong(_numCqsOnClientId, 1);
  }

  /**
   * Decrements the "numCqsOnClient" stat by 1.
   */
  void decCqsOnClient() {
    this._stats.incLong(_numCqsOnClientId, -1);
  }

  /**
   * Returns the current value of the "numClientsWithCqs" stat.
   *
   * @return the current value of the "numClientsWithCqs" stat
   */
  public long getNumClientsWithCqs() {
    return this._stats.getLong(_numClientsWithCqsId);
  }

  /**
   * Increments the "numClientsWithCqs" stat by 1.
   */
  void incClientsWithCqs() {
    this._stats.incLong(_numClientsWithCqsId, 1);
  }

  /**
   * Decrements the "numCqsOnClient" stat by 1.
   */
  void decClientsWithCqs() {
    this._stats.incLong(_numClientsWithCqsId, -1);
  }

  /**
   * Start the CQ Query Execution time.
   */
  long startCqQueryExecution() {
    this._stats.incInt(_cqQueryExecutionInProgressId, 1);
    return NanoTimer.getTime();
  }

  /**
   * End CQ Query Execution Time.
   *
   * @param start long time value.
   */
  void endCqQueryExecution(long start) {
    long ts = NanoTimer.getTime();
    this._stats.incLong(_cqQueryExecutionTimeId, ts - start);
    this._stats.incInt(_cqQueryExecutionInProgressId, -1);
    this._stats.incLong(_cqQueryExecutionsCompletedId, 1);
  }

  /**
   * Returns the total time spent executing the CQ Queries.
   *
   * @return long time spent.
   */
  public long getCqQueryExecutionTime() {
    return this._stats.getLong(_cqQueryExecutionTimeId);
  }

  /**
   * Increments number of Unique queries.
   */
  void incUniqueCqQuery() {
    this._stats.incInt(_numUniqueCqQuery, 1);
  }

  /**
   * Decrements number of unique Queries.
   */
  void decUniqueCqQuery() {
    this._stats.incInt(_numUniqueCqQuery, -1);
  }


  /**
   * This is a test method. It silently ignores exceptions and should not be used outside of unit
   * tests.
   * <p>
   * Returns the number of CQs (active + suspended) on the given region.
   */
  public long numCqsOnRegion(final InternalCache cache, String regionName) {
    if (cache == null) {
      return 0;
    }
    DefaultQueryService queryService = (DefaultQueryService) cache.getQueryService();
    CqService cqService = null;
    try {
      cqService = queryService.getCqService();
    } catch (CqException e) {
      if (logger.isDebugEnabled()) {
        logger.debug("Failed to get CqService {}", e.getLocalizedMessage());
      }
      e.printStackTrace();
      return -1; // We're confused
    }
    if (((CqServiceImpl) cqService).isServer()) {
      // If we are on the server, look at the number of CQs in the filter profile.
      try {
        FilterProfile fp = cache.getFilterProfile(regionName);
        if (fp == null) {
          return 0;
        }
        return fp.getCqCount();
      } catch (Exception ex) {
        if (logger.isDebugEnabled()) {
          logger.debug("Failed to get serverside CQ count for region: {} {}", regionName,
              ex.getLocalizedMessage());
        }
      }
    } else {
      try {
        CqQuery[] cqs = queryService.getCqs(regionName);

        if (cqs != null) {
          return cqs.length;
        }
      } catch (Exception ex) {
        // Dont do anything.
      }
    }
    return 0;
  }
}