/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * 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: George Riley <riley@ece.gatech.edu>

 */

#ifndef DISTRIBUTED_SIMULATOR_IMPL_H

#define DISTRIBUTED_SIMULATOR_IMPL_H

#include "ns3/simulator-impl.h"

#include "ns3/scheduler.h"

#include "ns3/event-impl.h"

#include "ns3/ptr.h"

#include <list>

namespace ns3 {

/**

 * \brief Structure used for all-reduce LBTS computation

 */

class LbtsMessage

{

public:

  LbtsMessage ()

    : m_txCount (0),

      m_rxCount (0),

      m_myId (0)

  {

  }

  /**

   * \param rxc received count

   * \param txc transmitted count

   * \param id mpi rank

   * \param t smallest time

   */

  LbtsMessage (uint32_t rxc, uint32_t txc, uint32_t id, const Time& t)

    : m_txCount (txc),

      m_rxCount (rxc),

      m_myId (id),

      m_smallestTime (t)

  {

  }

  ~LbtsMessage ();

  /**

   * \return smallest time

   */

  Time GetSmallestTime ();

  /**

   * \return transmitted count

   */

  uint32_t GetTxCount ();

  /**

   * \return receieved count

   */

  uint32_t GetRxCount ();

  /**

   * \return id which corresponds to mpi rank

   */

  uint32_t GetMyId ();

private:

  uint32_t m_txCount;

  uint32_t m_rxCount;

  uint32_t m_myId;

  Time     m_smallestTime;

};

/**

 * \brief distributed simulator implementation using lookahead

 */

class DistributedSimulatorImpl : public SimulatorImpl

{

public:

  static TypeId GetTypeId (void);

  DistributedSimulatorImpl ();

  ~DistributedSimulatorImpl ();

  // virtual from SimulatorImpl

  virtual void Destroy ();

  virtual bool IsFinished (void) const;

  virtual Time Next (void) const;

  virtual void Stop (void);

  virtual void Stop (Time const &time);

  virtual EventId Schedule (Time const &time, EventImpl *event);

  virtual void ScheduleWithContext (uint32_t context, Time const &time, EventImpl *event);

  virtual EventId ScheduleNow (EventImpl *event);

  virtual EventId ScheduleDestroy (EventImpl *event);

  virtual void Remove (const EventId &ev);

  virtual void Cancel (const EventId &ev);

  virtual bool IsExpired (const EventId &ev) const;

  virtual void Run (void);

  virtual void RunOneEvent (void);

  virtual Time Now (void) const;

  virtual Time GetDelayLeft (const EventId &id) const;

  virtual Time GetMaximumSimulationTime (void) const;

  virtual void SetScheduler (ObjectFactory schedulerFactory);

  virtual uint32_t GetSystemId (void) const;

  virtual uint32_t GetContext (void) const;

private:

  virtual void DoDispose (void);

  void CalculateLookAhead (void);

  void ProcessOneEvent (void);

  uint64_t NextTs (void) const;

  typedef std::list<EventId> DestroyEvents;

  DestroyEvents m_destroyEvents;

  bool m_stop;

  Ptr<Scheduler> m_events;

  uint32_t m_uid;

  uint32_t m_currentUid;

  uint64_t m_currentTs;

  uint32_t m_currentContext;

  // number of events that have been inserted but not yet scheduled,

  // not counting the "destroy" events; this is used for validation

  int m_unscheduledEvents;

  LbtsMessage* m_pLBTS;       // Allocated once we know how many systems

  uint32_t     m_myId;        // MPI Rank

  uint32_t     m_systemCount; // MPI Size

  Time         m_grantedTime; // Last LBTS

  static Time  m_lookAhead;   // Lookahead value

};

} // namespace ns3

#endif /* DISTRIBUTED_SIMULATOR_IMPL_H */