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

/*

 * Copyright (c) 2004,2005,2006 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: Federico Maguolo <maguolof@dei.unipd.it>

 */

#include "aarfcd-wifi-manager.h"

#include "ns3/assert.h"

#include "ns3/log.h"

#include "ns3/simulator.h"

#include "ns3/boolean.h"

#include <algorithm>

NS_LOG_COMPONENT_DEFINE ("Aarfcd");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED(AarfcdWifiManager);

AarfcdWifiRemoteStation::AarfcdWifiRemoteStation (Ptr<AarfcdWifiManager> manager)

  : m_manager (manager)

{

  m_timerTimeout = m_manager->m_minTimerThreshold;

  m_successThreshold = m_manager->m_minSuccessThreshold;

  m_rate = GetMinRate ();

  m_success = 0;

  m_failed = 0;

  m_recovery = false;

  m_retry = 0;

  m_timer = 0;

  m_rtsOn = false;

  m_rtsWnd = m_manager->m_minRtsWnd;

  m_rtsCounter = 0;

  m_justModifyRate = true;

  m_haveASuccess = false;

}

AarfcdWifiRemoteStation::~AarfcdWifiRemoteStation ()

{}

uint32_t

AarfcdWifiRemoteStation::GetMaxRate (void)

{

  return GetNSupportedModes () - 1;

}

uint32_t

AarfcdWifiRemoteStation::GetMinRate (void)

{

  return 0;

}

void

AarfcdWifiRemoteStation::ReportRecoveryFailure (void)

{

  m_successThreshold = (int)(std::min ((uint32_t)(m_successThreshold * m_manager->m_successK),

                                       m_manager->m_maxSuccessThreshold));

  m_timerTimeout = (int)(std::max (m_manager->m_minTimerThreshold,

                                   (uint32_t)(m_successThreshold * m_manager->m_timerK)));

}

void

AarfcdWifiRemoteStation::ReportFailure (void)

{

  m_timerTimeout = m_manager->m_minTimerThreshold;

  m_successThreshold = m_manager->m_minSuccessThreshold;

}

bool 

AarfcdWifiRemoteStation::NeedRecoveryFallback (void)

{

  if (m_retry >= 1) 

    {

      return true;

    } 

  else 

    {

      return false;

    }

}

bool 

AarfcdWifiRemoteStation::NeedNormalFallback (void)

{

  int retryMod = (m_retry - 1) % 2;

  if (retryMod == 1) 

    {

      return true;

    } 

  else 

    {

      return false;

    }

}

void 

AarfcdWifiRemoteStation::DoReportRtsFailed (void)

{

  //printf ("%.9f %p RtsFail %d %d %d\n",Simulator::Now ().GetSeconds (),this,m_rate,m_timer,m_retry);

  NS_LOG_INFO ("" << this << " RtsFail rate=" << m_rate);

  if (m_manager->m_rtsFailsAsDataFails)

    {

      m_rtsCounter--;

      ReportDataFailed ();

    }

}

/**

 * It is important to realize that "recovery" mode starts after failure of

 * the first transmission after a rate increase and ends at the first successful

 * transmission. Specifically, recovery mode transcends retransmissions boundaries.

 * Fundamentally, ARF handles each data transmission independently, whether it

 * is the initial transmission of a packet or the retransmission of a packet.

 * The fundamental reason for this is that there is a backoff between each data

 * transmission, be it an initial transmission or a retransmission.

 */

void 

AarfcdWifiRemoteStation::DoReportDataFailed (void)

{

  NS_LOG_INFO ("" << this << " TxFail rate=" << m_rate);

  m_timer++;

  m_failed++;

  m_retry++;

  m_success = 0;

  //printf ("%.9f %p Fail %d %d %d\n",Simulator::Now ().GetSeconds (),this,m_rate,m_timer,m_retry);

  if (!m_rtsOn) 

    {

      TurnOnRts ();

      if (!m_justModifyRate && !m_haveASuccess) 

        {

          //printf ("%p Increase RTS Windows\n",this);

          IncreaseRtsWnd ();

        }

      else 

        {

          //printf ("%p Reset RTS Window\n",this);

          ResetRtsWnd ();

        }

      m_rtsCounter = m_rtsWnd;

      if (m_retry >= 2) 

        {

          m_timer = 0;

        }

      //printf ("%.9f %p AtcivateRTS %d %d\n",Simulator::Now ().GetSeconds (),this, m_rate, m_rtsCounter);

    }

  else if (m_recovery) 

    {

      NS_ASSERT (m_retry >= 1);

      m_justModifyRate = false;

      m_rtsCounter = m_rtsWnd;

      if (NeedRecoveryFallback ()) 

        {

          if (m_manager->m_turnOffRtsAfterRateDecrease) 

            {

              TurnOffRts ();

            }

          m_justModifyRate = true;

          ReportRecoveryFailure ();

          if (m_rate != GetMinRate ()) 

            {

              m_rate--;

            }

          NS_LOG_INFO ("" << this << " JD rate=" << m_rate << " Sthr=" << m_successThreshold);

          //printf ("%.9f %p DecreaseRateRecovery %d\n", Simulator::Now ().GetSeconds (),this, m_rate);

        }

      m_timer = 0;

    } 

  else 

    {

      NS_ASSERT (m_retry >= 1);

      m_justModifyRate = false;

      m_rtsCounter = m_rtsWnd;

      if (NeedNormalFallback ()) 

        {

          if (m_manager->m_turnOffRtsAfterRateDecrease) 

            {

              TurnOffRts ();

            }

          m_justModifyRate = true;

          ReportFailure ();

          if (m_rate != GetMinRate ()) 

            {

              m_rate--;

            }

          NS_LOG_INFO ("" << this << " JD rate=" << m_rate << " Sthr=" << m_successThreshold);

          //printf ("%.9f %p DecreaseRate %d\n", Simulator::Now ().GetSeconds (),this,m_rate);

        }

      if (m_retry >= 2) 

        {

          m_timer = 0;

        }

    }

  CheckRts ();

}

void 

AarfcdWifiRemoteStation::DoReportRxOk (double rxSnr, WifiMode txMode)

{}

void 

AarfcdWifiRemoteStation::DoReportRtsOk (double ctsSnr, WifiMode ctsMode, double rtsSnr)

{

  NS_LOG_INFO ("" << this << " RtsOk rate=" << m_rate);

  NS_LOG_DEBUG ("self="<<this<<" rts ok");

  m_rtsCounter--;

}

void 

AarfcdWifiRemoteStation::DoReportDataOk (double ackSnr, WifiMode ackMode, double dataSnr)

{

  NS_LOG_INFO ("" << this << " TxOk rate=" << m_rate);

  m_timer++;

  m_success++;

  m_failed = 0;

  m_recovery = false;

  m_retry = 0;

  m_justModifyRate = false;

  m_haveASuccess = true;

  //printf ("%.9f %p Ok %d %d %d\n",Simulator::Now ().GetSeconds (),this,m_rate,m_timer,m_retry);

  //printf ("%p OK (m_success=%d, th=%d, m_rate=%d, maxRate=%d)\n",this,m_success,GetSuccessThreshold (), m_rate, GetMaxRate ());

  NS_LOG_DEBUG ("self="<<this<<" data ok success="<<m_success<<", timer="<<m_timer);

  if ((m_success == m_successThreshold ||

       m_timer >= m_timerTimeout) &&

      (m_rate < GetMaxRate ())) 

    {

      NS_LOG_DEBUG ("self="<<this<<" inc rate");

      m_rate++;

      NS_LOG_INFO ("" << this << " JI rate=" << m_rate << " Sthr=" << m_successThreshold);

      m_timer = 0;

      m_success = 0;

      m_recovery = true;

      m_justModifyRate = true;

      if (m_manager->m_turnOnRtsAfterRateIncrease) 

        {

          TurnOnRts ();

          ResetRtsWnd ();

          m_rtsCounter = m_rtsWnd;

        }

      //printf ("%.9f %p IncreaseRate %d %d\n", Simulator::Now ().GetSeconds (),this,m_rate,(m_rtsOn?1:0));

    }

  else if (m_success == m_successThreshold ||

           m_timer >= m_timerTimeout) 

    {

      NS_LOG_INFO ("" << this << " JI rate=" << m_rate << " Sthr=" << m_successThreshold);

    }

  CheckRts ();

}

void 

AarfcdWifiRemoteStation::DoReportFinalRtsFailed (void)

{}

void 

AarfcdWifiRemoteStation::DoReportFinalDataFailed (void)

{}

WifiMode

AarfcdWifiRemoteStation::DoGetDataMode (uint32_t size)

{

  return GetSupportedMode (m_rate);

}

WifiMode

AarfcdWifiRemoteStation::DoGetRtsMode (void)

{

  // XXX: we could/should implement the Arf algorithm for

  // RTS only by picking a single rate within the BasicRateSet.

  return GetSupportedMode (0);

}

Ptr<WifiRemoteStationManager>

AarfcdWifiRemoteStation::GetManager (void) const

{

  return m_manager;

}

void

AarfcdWifiRemoteStation::CheckRts (void)

{

  if (m_rtsCounter == 0 && m_rtsOn) 

    {

      //printf ("%p Turn off RTS\n",this);

      TurnOffRts ();

    }

}

void

AarfcdWifiRemoteStation::TurnOffRts (void)

{

  //printf ("%.9f %p DeatcivateRTS %d %d\n",Simulator::Now ().GetSeconds (),this, m_rate, m_rtsCounter);

  m_rtsOn = false;

  m_haveASuccess = false;

}

void

AarfcdWifiRemoteStation::TurnOnRts (void)

{

  m_rtsOn = true;

}

void

AarfcdWifiRemoteStation::IncreaseRtsWnd (void)

{

  if (m_rtsWnd == m_manager->m_maxRtsWnd)

    {

      return;

    }

  m_rtsWnd *= 2;

  if (m_rtsWnd > m_manager->m_maxRtsWnd)

    {

      m_rtsWnd = m_manager->m_maxRtsWnd;

    }

}

void

AarfcdWifiRemoteStation::ResetRtsWnd (void)

{

  m_rtsWnd = m_manager->m_minRtsWnd;

}

bool

AarfcdWifiRemoteStation::NeedRts (Ptr<const Packet> packet)

{

  //printf ("%.9f %p NeedRts %d %d\n",Simulator::Now ().GetSeconds (),this,m_rate,(m_rtsOn?1:0));

  NS_LOG_INFO ("" << this << " rate=" << m_rate << " rts=" << (m_rtsOn?"RTS":"BASIC") << " rtsCounter=" << m_rtsCounter);

  return m_rtsOn;

}

TypeId 

AarfcdWifiManager::GetTypeId (void)

{

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

    .SetParent<WifiRemoteStationManager> ()

    .AddConstructor<AarfcdWifiManager> ()

    .AddAttribute ("SuccessK", "Multiplication factor for the success threshold in the AARF algorithm.",

                   DoubleValue (2.0),

                   MakeDoubleAccessor (&AarfcdWifiManager::m_successK),

                   MakeDoubleChecker<double> ())

    .AddAttribute ("TimerK",

                   "Multiplication factor for the timer threshold in the AARF algorithm.",

                   DoubleValue (2.0),

                   MakeDoubleAccessor (&AarfcdWifiManager::m_timerK),

                   MakeDoubleChecker<double> ())

    .AddAttribute ("MaxSuccessThreshold",

                   "Maximum value of the success threshold in the AARF algorithm.",

                   UintegerValue (60),

                   MakeUintegerAccessor (&AarfcdWifiManager::m_maxSuccessThreshold),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("MinTimerThreshold",

                   "The minimum value for the 'timer' threshold in the AARF algorithm.",

                   UintegerValue (15),

                   MakeUintegerAccessor (&AarfcdWifiManager::m_minTimerThreshold),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("MinSuccessThreshold",

                   "The minimum value for the success threshold in the AARF algorithm.",

                   UintegerValue (10),

                   MakeUintegerAccessor (&AarfcdWifiManager::m_minSuccessThreshold),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("MinRtsWnd", 

                   "Minimum value for Rts window of Aarf-CD",

                   UintegerValue (1),

                   MakeUintegerAccessor (&AarfcdWifiManager::m_minRtsWnd),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("MaxRtsWnd", 

                   "Maximum value for Rts window of Aarf-CD",

                   UintegerValue (40),

                   MakeUintegerAccessor (&AarfcdWifiManager::m_maxRtsWnd),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("RtsFailsAsDataFails",

                   "If true the RTS failures will be treated by Aarf-CD as Data failures",

                   BooleanValue (false),

                   MakeBooleanAccessor (&AarfcdWifiManager::m_rtsFailsAsDataFails),

                   MakeBooleanChecker ())

    .AddAttribute ("TurnOffRtsAfterRateDecrease",

                   "If true the RTS mechanism will be turned off when the rate will be decreased",

                   BooleanValue (true),

                   MakeBooleanAccessor (&AarfcdWifiManager::m_turnOffRtsAfterRateDecrease),

                   MakeBooleanChecker ())

    .AddAttribute ("TurnOnRtsAfterRateIncrease",

                   "If true the RTS mechanism will be turned on when the rate will be increased",

                   BooleanValue (true),

                   MakeBooleanAccessor (&AarfcdWifiManager::m_turnOnRtsAfterRateIncrease),

                   MakeBooleanChecker ())

    ;

  return tid;

}

AarfcdWifiManager::AarfcdWifiManager ()

  : WifiRemoteStationManager ()

{}

AarfcdWifiManager::~AarfcdWifiManager ()

{}

WifiRemoteStation *

AarfcdWifiManager::CreateStation (void)

{

  return new AarfcdWifiRemoteStation (this);

}

} // namespace ns3