/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2011 University of California, Los Angeles
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
 */

#ifndef _CCNX_PIT_H_
#define	_CCNX_PIT_H_

#include "ns3/object.h"
#include "ns3/nstime.h"
#include "ns3/event-id.h"

#include "ccnx-name-components-hash-helper.h"
#include "ccnx-pit-entry.h"

#include <boost/multi_index_container.hpp>
#include <boost/multi_index/tag.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <boost/multi_index/composite_key.hpp>
#include <boost/multi_index/hashed_index.hpp>
#include <boost/multi_index/member.hpp>
#include <boost/multi_index/mem_fun.hpp>
#include <map>
#include <iostream>
#include <algorithm>
#include <boost/tuple/tuple.hpp>

namespace ns3 {

class Ccnx;
class CcnxFace;
class CcnxContentObjectHeader;
class CcnxInterestHeader;

/// @cond include_hidden
/**
 * \ingroup ccnx
 * \private
 * \brief Private namespace for CCNx PIT implementation
 */
namespace __ccnx_private
{
// class i_prefix{}; ///< tag for prefix hash
class i_timestamp {}; ///< tag for timestamp-ordered records (for cleanup optimization)  
};
/// @endcond

/**
 * \ingroup ccnx
 * \brief Typedef for RIT container implemented as a Boost.MultiIndex container
 *
 * - First index (tag<i_prefix>) is a unique hash index based on
 *   prefixes
 * - Second index (tag<i_timestamp>) is a sequenced index based on
 *   arrival order (for clean-up optimizations)
 *
 * \see http://www.boost.org/doc/libs/1_46_1/libs/multi_index/doc/ for more information on Boost.MultiIndex library
 */
struct CcnxPitEntryContainer
{
  /// @cond include_hidden
  typedef
  boost::multi_index::multi_index_container<
    CcnxPitEntry,
    boost::multi_index::indexed_by<
      // indexed by hash
      boost::multi_index::hashed_unique<
        boost::multi_index::tag<__ccnx_private::i_prefix>,
        boost::multi_index::const_mem_fun<CcnxPitEntry, const CcnxNameComponents&, &CcnxPitEntry::GetPrefix>,
        CcnxPrefixHash
        >,
      // sequenced to implement MRU
      boost::multi_index::ordered_non_unique<
        boost::multi_index::tag<__ccnx_private::i_timestamp>,
        boost::multi_index::member<CcnxPitEntry, Time, &CcnxPitEntry::m_expireTime>
        >
      >
    > type;
  /// @endcond
};

////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////

/**
 * \ingroup ccnx
 * \brief Class implementing Pending Interests Table
 */
class CcnxPit : public CcnxPitEntryContainer::type, public Object
{
public:
  /**
   * \brief Interface ID
   *
   * \return interface ID
   */
  static TypeId GetTypeId ();

  /**
   * \brief PIT constructor
   */
  CcnxPit ();

  /**
   * \brief Destructor
   */
  virtual ~CcnxPit ();
  
  /**
   * \brief Find corresponding PIT entry for the given content name
   * \param prefix Prefix for which to lookup the entry
   * \returns const reference to Pit entry. If record not found,
   *          CcnxPitEntryNotFound exception will be thrown
   */
  CcnxPitEntryContainer::type::iterator
  Lookup (const CcnxContentObjectHeader &header) const;

  /**
   * \brief Find corresponding PIT entry for the given content name
   * \param prefix Prefix for which to lookup the entry
   * \returns a tuple:
   * get<0>: `const CcnxPitEntry&`: a valid PIT entry (if record does not exist, it will be created)
   * get<1>: `bool`: true if a new entry was created
   * get<2>: `bool`: true if a PIT entry exists and Nonce that present in header has been already seen
   * 
   */
  boost::tuple<const CcnxPitEntry&, bool, bool>
  Lookup (const CcnxInterestHeader &header);

  /**
   * @brief Get pruning timeout for PIT entries (configuration parameter)
   */
  Time GetPitEntryPruningTimeout () const
  {
    return m_PitEntryPruningTimout;
  }
  
protected:
  // inherited from Object class                                                                                                                                                        
  virtual void NotifyNewAggregate (); ///< @brief Even when object is aggregated to another Object
  virtual void DoDispose (); ///< @brief Do cleanup
  	
private:
  /** \brief Remove expired records from PIT */
  void CleanExpired ();

  /**
   * \brief Set cleanup timeout
   *
   * Side effect: current clean up even (if any) will be cancelled and a new event started
   *
   * \param timeout cleanup timeout
   */
  void SetCleanupTimeout (const Time &timeout);

  /**
   * \brief Get cleanup timeout
   *
   * \returns cleanup timeout
   */
  Time GetCleanupTimeout () const;

  friend std::ostream& operator<< (std::ostream& os, const CcnxPit &fib);
  
private:
  Time    m_cleanupTimeout; ///< \brief Configurable timeout of how often cleanup events are working
  EventId m_cleanupEvent;   ///< \brief Cleanup event

  // configuration variables. Check implementation of GetTypeId for more details
  Time    m_PitEntryPruningTimout;
  Time    m_PitEntryDefaultLifetime;

  uint32_t m_maxSize;

  Ptr<CcnxFib> m_fib; ///< \brief Link to FIB table
};

///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////

std::ostream& operator<< (std::ostream& os, const CcnxPit &pit);

/**
 * @brief Class for exception when PIT entry is not found
 */
class CcnxPitEntryNotFound {};

} // namespace ns3

#endif	/* CCNX_PIT_H */