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

/*

 * Copyright (c) 2005,2006 INRIA

 *

 * 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: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 */

#include "simulator.h"

#include "default-simulator-impl.h"

#include "scheduler.h"

#include "event-impl.h"

#include "ns3/ptr.h"

#include "ns3/pointer.h"

#include "ns3/assert.h"

#include "ns3/log.h"

#include <math.h>

NS_LOG_COMPONENT_DEFINE ("DefaultSimulatorImpl");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (DefaultSimulatorImpl);

TypeId

DefaultSimulatorImpl::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::DefaultSimulatorImpl")

    .SetParent<Object> ()

    .AddConstructor<DefaultSimulatorImpl> ()

    ;

  return tid;

}

DefaultSimulatorImpl::DefaultSimulatorImpl ()

{

  m_stop = false;

  m_stopAt = 0;

  // uids are allocated from 4.

  // uid 0 is "invalid" events

  // uid 1 is "now" events

  // uid 2 is "destroy" events

  m_uid = 4; 

  // before ::Run is entered, the m_currentUid will be zero

  m_currentUid = 0;

  m_logEnable = false;

  m_currentTs = 0;

  m_unscheduledEvents = 0;

}

DefaultSimulatorImpl::~DefaultSimulatorImpl ()

{

  while (!m_events->IsEmpty ())

    {

      EventId next = m_events->RemoveNext ();

    }

  m_events = 0;

}

void

DefaultSimulatorImpl::Destroy ()

{

  while (!m_destroyEvents.empty ()) 

    {

      Ptr<EventImpl> ev = m_destroyEvents.front ().PeekEventImpl ();

      m_destroyEvents.pop_front ();

      NS_LOG_LOGIC ("handle destroy " << ev);

      if (!ev->IsCancelled ())

        {

          ev->Invoke ();

        }

    }

}

void

DefaultSimulatorImpl::SetScheduler (Ptr<Scheduler> scheduler)

{

  if (m_events != 0)

    {

      while (!m_events->IsEmpty ())

        {

          EventId next = m_events->RemoveNext ();

          scheduler->Insert (next);

        }

    }

  m_events = scheduler;

}

Ptr<Scheduler>

DefaultSimulatorImpl::GetScheduler (void) const

{

  return m_events;

}

void

DefaultSimulatorImpl::EnableLogTo (char const *filename)

{

  m_log.open (filename);

  m_logEnable = true;

}

void

DefaultSimulatorImpl::ProcessOneEvent (void)

{

  EventId next = m_events->RemoveNext ();

  NS_ASSERT (next.GetTs () >= m_currentTs);

  --m_unscheduledEvents;

  NS_LOG_LOGIC ("handle " << next.GetTs ());

  m_currentTs = next.GetTs ();

  m_currentUid = next.GetUid ();

  if (m_logEnable) 

    {

      m_log << "e "<<next.GetUid () << " " << next.GetTs () << std::endl;

    }

  EventImpl *event = next.PeekEventImpl ();

  event->Invoke ();

}

bool 

DefaultSimulatorImpl::IsFinished (void) const

{

  return m_events->IsEmpty ();

}

uint64_t

DefaultSimulatorImpl::NextTs (void) const

{

  NS_ASSERT (!m_events->IsEmpty ());

  EventId id = m_events->PeekNext ();

  return id.GetTs ();

}

Time

DefaultSimulatorImpl::Next (void) const

{

  return TimeStep (NextTs ());

}

void

DefaultSimulatorImpl::Run (void)

{

  while (!m_events->IsEmpty () && !m_stop && 

         (m_stopAt == 0 || m_stopAt > NextTs ())) 

    {

      ProcessOneEvent ();

    }

  // If the simulator stopped naturally by lack of events, make a

  // consistency test to check that we didn't lose any events along the way.

  NS_ASSERT(!m_events->IsEmpty () || m_unscheduledEvents == 0);

  m_log.close ();

}

void 

DefaultSimulatorImpl::Stop (void)

{

  m_stop = true;

}

void 

DefaultSimulatorImpl::Stop (Time const &time)

{

  NS_ASSERT (time.IsPositive ());

  Time absolute = Simulator::Now () + time;

  m_stopAt = absolute.GetTimeStep ();

}

EventId

DefaultSimulatorImpl::Schedule (Time const &time, const Ptr<EventImpl> &event)

{

  NS_ASSERT (time.IsPositive ());

  NS_ASSERT (time >= TimeStep (m_currentTs));

  uint64_t ts = (uint64_t) time.GetTimeStep ();

  EventId id (event, ts, m_uid);

  if (m_logEnable) 

    {

      m_log << "i "<<m_currentUid<<" "<<m_currentTs<<" "

            <<m_uid<<" "<<time.GetTimeStep () << std::endl;

    }

  m_uid++;

  ++m_unscheduledEvents;

  m_events->Insert (id);

  return id;

}

EventId

DefaultSimulatorImpl::ScheduleNow (const Ptr<EventImpl> &event)

{

  EventId id (event, m_currentTs, m_uid);

  if (m_logEnable) 

    {

      m_log << "i "<<m_currentUid<<" "<<m_currentTs<<" "

            <<m_uid<<" "<<m_currentTs << std::endl;

    }

  m_uid++;

  ++m_unscheduledEvents;

  m_events->Insert (id);

  return id;

}

EventId

DefaultSimulatorImpl::ScheduleDestroy (const Ptr<EventImpl> &event)

{

  EventId id (event, m_currentTs, 2);

  m_destroyEvents.push_back (id);

  if (m_logEnable) 

  {

    m_log << "id " << m_currentUid << " " << Now ().GetTimeStep () << " "

          << m_uid << std::endl;

  }

  m_uid++;

  return id;

}

Time

DefaultSimulatorImpl::Now (void) const

{

  return TimeStep (m_currentTs);

}

Time 

DefaultSimulatorImpl::GetDelayLeft (const EventId &id) const

{

  if (IsExpired (id))

    {

      return TimeStep (0);

    }

  else

    {

      return TimeStep (id.GetTs () - m_currentTs);

    }

}

void

DefaultSimulatorImpl::Remove (const EventId &ev)

{

  if (ev.GetUid () == 2)

    {

      // destroy events.

      for (DestroyEvents::iterator i = m_destroyEvents.begin (); i != m_destroyEvents.end (); i++)

        {

          if (*i == ev)

            {

              m_destroyEvents.erase (i);

              break;

            }

         }

      return;

    }

  if (IsExpired (ev))

    {

      return;

    }

  m_events->Remove (ev);

  Cancel (ev);

  if (m_logEnable) 

    {

      m_log << "r " << m_currentUid << " " << m_currentTs << " "

            << ev.GetUid () << " " << ev.GetTs () << std::endl;

    }

  --m_unscheduledEvents;

}

void

DefaultSimulatorImpl::Cancel (const EventId &id)

{

  if (!IsExpired (id))

    {

      id.PeekEventImpl ()->Cancel ();

    }

}

bool

DefaultSimulatorImpl::IsExpired (const EventId &ev) const

{

  if (ev.GetUid () == 2)

    {

      // destroy events.

      for (DestroyEvents::const_iterator i = m_destroyEvents.begin (); i != m_destroyEvents.end (); i++)

        {

          if (*i == ev)

            {

              return false;

            }

         }

      return true;

    }

  if (ev.PeekEventImpl () == 0 ||

      ev.GetTs () < m_currentTs ||

      (ev.GetTs () == m_currentTs &&

       ev.GetUid () <= m_currentUid) ||

      ev.PeekEventImpl ()->IsCancelled ()) 

    {

      return true;

    }

  else

    {

      return false;

    }

}

Time 

DefaultSimulatorImpl::GetMaximumSimulationTime (void) const

{

  // XXX: I am fairly certain other compilers use other non-standard

  // post-fixes to indicate 64 bit constants.

  return TimeStep (0x7fffffffffffffffLL);

}

}; // namespace ns3