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

/*

 * Copyright (c) 2014 Universidad de la República - Uruguay

 *

 * 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: Matias Richart <mrichart@fing.edu.uy>

 */

#include "aparf-wifi-manager.h"

#include "wifi-phy.h"

#include "ns3/assert.h"

#include "ns3/log.h"

#include "ns3/uinteger.h"

#include "ns3/trace-source-accessor.h"

#define Min(a,b) ((a < b) ? a : b)

NS_LOG_COMPONENT_DEFINE ("ns3::AparfWifiManager");

namespace ns3 {

/**

 * Hold per-remote-station state for APARF Wifi manager.

 *

 * This struct extends from WifiRemoteStation struct to hold additional

 * information required by the APARF Wifi manager

 */

struct

AparfWifiRemoteStation : public WifiRemoteStation

{

  uint32_t m_nSuccess; //!< Number of successful transmission attempts.

  uint32_t m_nFailed; //!< Number of failed transmission attempts.

  uint32_t m_pCount; //!< Number of power changes.

  uint32_t m_successThreshold; //!< The minimum number of successful transmissions to try a new power or rate.

  uint32_t m_failThreshold; //!< The minimum number of failed transmissions to try a new power or rate.

  uint32_t m_rate; //!< Current rate.

  uint32_t m_rateCrit; //!< Critical rate.

  uint8_t m_power; //!< Current power.

  uint32_t m_nSupported; //!< Number of supported rates by the remote station.

  bool m_initialized; //!< For initializing variables.

  AparfWifiManager::State m_aparfState; //!< The estimated state of the channel.

};

NS_OBJECT_ENSURE_REGISTERED (AparfWifiManager);

TypeId

AparfWifiManager::GetTypeId (void)

{

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

    .SetParent<WifiRemoteStationManager> ()

    .AddConstructor<AparfWifiManager> ()

    .AddAttribute ("SuccessThreshold 1",

                   "The minimum number of successful transmissions in \"High\" state to try a new power or rate.",

                   UintegerValue (3),

                   MakeUintegerAccessor (&AparfWifiManager::m_succesMax1),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("SuccessThreshold 2",

                   "The minimum number of successful transmissions in \"Low\" state to try a new power or rate.",

                   UintegerValue (10),

                   MakeUintegerAccessor (&AparfWifiManager::m_succesMax2),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("FailThreshold",

                   "The minimum number of failed transmissions to try a new power or rate.",

                   UintegerValue (1),

                   MakeUintegerAccessor (&AparfWifiManager::m_failMax),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("PowerThreshold",

                   "The maximum number of power changes.",

                   UintegerValue (10),

                   MakeUintegerAccessor (&AparfWifiManager::m_powerMax),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("Power decrement step",

                   "Step size for decrement the power.",

                   UintegerValue (1),

                   MakeUintegerAccessor (&AparfWifiManager::m_powerDec),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("Power increment step",

                   "Step size for increment the power.",

                   UintegerValue (1),

                   MakeUintegerAccessor (&AparfWifiManager::m_powerInc),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("Rate decrement step",

                   "Step size for decrement the rate.",

                   UintegerValue (1),

                   MakeUintegerAccessor (&AparfWifiManager::m_rateDec),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("Rate increment step",

                   "Step size for increment the rate.",

                   UintegerValue (1),

                   MakeUintegerAccessor (&AparfWifiManager::m_rateInc),

                   MakeUintegerChecker<uint32_t> ())

    .AddTraceSource ("PowerChange",

                     "The transmission power has change",

                     MakeTraceSourceAccessor (&AparfWifiManager::m_powerChange),

                     "ns3::AparfWifiManager::PowerChangeTracedCallback")

    .AddTraceSource ("RateChange",

                     "The transmission rate has change",

                     MakeTraceSourceAccessor (&AparfWifiManager::m_rateChange),

                     "ns3::AparfWifiManager::RateChangeTracedCallback")

  ;

  return tid;

}

AparfWifiManager::AparfWifiManager ()

{

  NS_LOG_FUNCTION (this);

}

AparfWifiManager::~AparfWifiManager ()

{

  NS_LOG_FUNCTION (this);

}

void

AparfWifiManager::SetupPhy (Ptr<WifiPhy> phy)

{

  m_nPower = phy->GetNTxPower ();

  WifiRemoteStationManager::SetupPhy (phy);

}

WifiRemoteStation *

AparfWifiManager::DoCreateStation (void) const

{

  NS_LOG_FUNCTION (this);

  AparfWifiRemoteStation *station = new AparfWifiRemoteStation ();

  station->m_successThreshold = m_succesMax1;

  station->m_failThreshold = m_failMax;

  station->m_nSuccess = 0;

  station->m_nFailed = 0;

  station->m_pCount = 0;

  station->m_aparfState = AparfWifiManager::High;

  station->m_initialized = false;

  NS_LOG_DEBUG ("create station=" << station << ", rate=" << station->m_rate

                                  << ", power=" << (int)station->m_power);

  return station;

}

void

AparfWifiManager::CheckInit (AparfWifiRemoteStation *station)

{

  if (!station->m_initialized)

    {

      station->m_nSupported = GetNSupported (station);

      station->m_rate = station->m_nSupported - 1;

      station->m_power = m_nPower - 1;

      station->m_rateCrit = 0;

      m_powerChange (station->m_power, station->m_state->m_address);

      m_rateChange (station->m_rate, station->m_state->m_address);

      station->m_initialized = true;

    }

}

void AparfWifiManager::DoReportRtsFailed (WifiRemoteStation *station)

{

  NS_LOG_FUNCTION (this << station);

}

void AparfWifiManager::DoReportDataFailed (WifiRemoteStation *st)

{

  NS_LOG_FUNCTION (this << st);

  AparfWifiRemoteStation *station = (AparfWifiRemoteStation *) st;

  CheckInit (station);

  station->m_nFailed++;

  station->m_nSuccess = 0;

  NS_LOG_DEBUG ("station=" << station << ", rate=" << station->m_rate

                           << ", power=" << (int)station->m_power);

  if (station->m_aparfState == AparfWifiManager::Low)

    {

      station->m_aparfState = AparfWifiManager::High;

      station->m_successThreshold = m_succesMax1;

    }

  else if (station->m_aparfState == AparfWifiManager::Spread)

    {

      station->m_aparfState = AparfWifiManager::Low;

      station->m_successThreshold = m_succesMax2;

    }

  if (station->m_nFailed == station->m_failThreshold)

    {

      station->m_nFailed = 0;

      station->m_nSuccess = 0;

      station->m_pCount = 0;

      if (station->m_power == (m_nPower - 1))

        {

          station->m_rateCrit = station->m_rate;

          if (station->m_rate != 0)

            {

              NS_LOG_DEBUG ("station=" << station << " dec rate");

              station->m_rate -= m_rateDec;

              m_rateChange (station->m_rate, station->m_state->m_address);

            }

        }

      else

        {

          NS_LOG_DEBUG ("station=" << station << " inc power");

          station->m_power += m_powerInc;

          m_powerChange (station->m_power, station->m_state->m_address);

        }

    }

}

void

AparfWifiManager::DoReportRxOk (WifiRemoteStation *station, double rxSnr, WifiMode txMode)

{

  NS_LOG_FUNCTION (this << station << rxSnr << txMode);

}

void

AparfWifiManager::DoReportRtsOk (WifiRemoteStation *station, double ctsSnr,

                                 WifiMode ctsMode, double rtsSnr)

{

  NS_LOG_FUNCTION (this << station << ctsSnr << ctsMode << rtsSnr);

  NS_LOG_DEBUG ("station=" << station << " rts ok");

}

void

AparfWifiManager::DoReportDataOk (WifiRemoteStation *st, double ackSnr,

                                  WifiMode ackMode, double dataSnr)

{

  NS_LOG_FUNCTION (this << st << ackSnr << ackMode << dataSnr);

  AparfWifiRemoteStation *station = (AparfWifiRemoteStation *) st;

  CheckInit (station);

  station->m_nSuccess++;

  station->m_nFailed = 0;

  NS_LOG_DEBUG ("station=" << station << " data ok success=" << station->m_nSuccess << ", rate=" << station->m_rate << ", power=" << (int)station->m_power);

  if ((station->m_aparfState == AparfWifiManager::High) && (station->m_nSuccess >= station->m_successThreshold))

    {

      station->m_aparfState = AparfWifiManager::Spread;

    }

  else if ((station->m_aparfState == AparfWifiManager::Low) && (station->m_nSuccess >= station->m_successThreshold))

    {

      station->m_aparfState = AparfWifiManager::Spread;

    }

  else if (station->m_aparfState == AparfWifiManager::Spread)

    {

      station->m_aparfState = AparfWifiManager::High;

      station->m_successThreshold = m_succesMax1;

    }

  if (station->m_nSuccess == station->m_successThreshold)

    {

      station->m_nSuccess = 0;

      station->m_nFailed = 0;

      if (station->m_rate == (station->m_state->m_operationalRateSet.size () - 1))

        {

          if (station->m_power != 0)

            {

              NS_LOG_DEBUG ("station=" << station << " dec power");

              station->m_power -= m_powerDec;

              m_powerChange (station->m_power, station->m_state->m_address);

            }

        }

      else

        {

          if (station->m_rateCrit == 0)

            {

              if (station->m_rate != (station->m_state->m_operationalRateSet.size () - 1))

                {

                  NS_LOG_DEBUG ("station=" << station << " inc rate");

                  station->m_rate += m_rateInc;

                  m_rateChange (station->m_rate, station->m_state->m_address);

                }

            }

          else

            {

              if (station->m_pCount == m_powerMax)

                {

                  station->m_power = (m_nPower - 1);

                  m_powerChange (station->m_power, station->m_state->m_address);

                  station->m_rate = station->m_rateCrit;

                  m_rateChange (station->m_rate, station->m_state->m_address);

                  station->m_pCount = 0;

                  station->m_rateCrit = 0;

                }

              else

                {

                  if (station->m_power != 0)

                    {

                      station->m_power -= m_powerDec;

                      m_powerChange (station->m_power, station->m_state->m_address);

                      station->m_pCount++;

                    }

                }

            }

        }

    }

}

void

AparfWifiManager::DoReportFinalRtsFailed (WifiRemoteStation *station)

{

  NS_LOG_FUNCTION (this << station);

}

void

AparfWifiManager::DoReportFinalDataFailed (WifiRemoteStation *station)

{

  NS_LOG_FUNCTION (this << station);

}

WifiTxVector

AparfWifiManager::DoGetDataTxVector (WifiRemoteStation *st, uint32_t size)

{

  NS_LOG_FUNCTION (this << st << size);

  AparfWifiRemoteStation *station = (AparfWifiRemoteStation *) st;

  CheckInit (station);

  return WifiTxVector (GetSupported (station, station->m_rate), station->m_power, GetLongRetryCount (station), GetShortGuardInterval (station), Min (GetNumberOfReceiveAntennas (station),GetNumberOfTransmitAntennas ()), GetNumberOfTransmitAntennas (station), GetStbc (station));

}

WifiTxVector

AparfWifiManager::DoGetRtsTxVector (WifiRemoteStation *st)

{

  NS_LOG_FUNCTION (this << st);

  /// \todo we could/should implement the Arf algorithm for

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

  AparfWifiRemoteStation *station = (AparfWifiRemoteStation *) st;

  return WifiTxVector (GetSupported (station, 0), GetDefaultTxPowerLevel (), GetShortRetryCount (station), GetShortGuardInterval (station), Min (GetNumberOfReceiveAntennas (station),GetNumberOfTransmitAntennas ()), GetNumberOfTransmitAntennas (station), GetStbc (station));

}

bool

AparfWifiManager::IsLowLatency (void) const

{

  NS_LOG_FUNCTION (this);

  return true;

}

} // namespace ns3