/*
 * Copyright (C) 2010 Joseph Daly <skinny.moey@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 *   * Neither the name of Joseph Daly nor the names of its contributors
 *     may be used to endorse or promote products derived from this software
 *     without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#ifndef PLUGIN_LOGGING_STATS_SCOREBOARD_H
#define PLUGIN_LOGGING_STATS_SCOREBOARD_H

#include "scoreboard_slot.h"
#include <drizzled/session.h>
#include <boost/thread/shared_mutex.hpp>

#include <vector>

class Scoreboard
{
public:
  Scoreboard(uint32_t in_number_sessions, uint32_t in_number_buckets);

  ~Scoreboard();

  /**
   * Locates a ScoreboardSlot that is not in use, marks the slot
   * as being used and returns a pointer to it. The caller can
   * update individual statistics via the pointer without having
   * to lock or worry about concurrent updates.  
   * 
   * @param Pointer to the session 
   * @return Pointer to the ScoreboardSlot whose individual statistics 
   *   can be updated
   */
  ScoreboardSlot* findScoreboardSlotToLog(drizzled::Session *session);

  /**
   * Finds the ScoreboardSlot for a given session. This function differs
   * from findAndResetScoreboardSlot() as it returns the actual pointer
   * rather then a copy. Its possible that values could be changed in 
   * the underlying status variables, callers should beware. 
   */
  ScoreboardSlot* findOurScoreboardSlot(drizzled::Session *session);

  uint32_t getBucketNumber(drizzled::Session *session);

  uint32_t getNumberBuckets()
  {
    return number_buckets;
  }

  uint32_t getNumberPerBucket()
  {
    return number_per_bucket;
  }

  uint64_t getScoreboardSizeBytes()
  {
    return scoreboard_size_bytes;
  } 

  std::vector<boost::shared_mutex* >* getVectorOfScoreboardLocks()
  {
    return &vector_of_scoreboard_locks;
  }

  std::vector<std::vector<ScoreboardSlot* >* >* getVectorOfScoreboardVectors()
  {
    return &vector_of_scoreboard_vectors; 
  }

private:
  uint32_t number_sessions;
  uint32_t number_per_bucket;
  uint32_t number_buckets;
  uint64_t scoreboard_size_bytes;
  std::vector<std::vector<ScoreboardSlot* >* > vector_of_scoreboard_vectors;
  std::vector<boost::shared_mutex* > vector_of_scoreboard_locks;

  ScoreboardSlot* claimOpenScoreboardSlot(drizzled::Session *session); 
};

#endif /* PLUGIN_LOGGING_STATS_SCOREBOARD_H */
