/* -*- 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 "parf-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::ParfWifiManager");

namespace ns3 {

/**

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

 *

 * This struct extends from WifiRemoteStation struct to hold additional

 * information required by the PARF Wifi manager

 */

struct ParfWifiRemoteStation : public WifiRemoteStation

{

  uint32_t m_nAttempt;       //!< Number of transmission attempts.

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

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

  bool m_usingRecoveryRate;  //!< If using recovery rate.

  bool m_usingRecoveryPower; //!< If using recovery power.

  uint32_t m_nRetry;         //!< Number of transmission retries.

  uint32_t m_currentRate;    //!< Current rate used by the remote station.

  uint8_t m_currentPower;    //!< Current power used by the remote station.

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

  bool m_initialized;        //!< For initializing variables.

};

NS_OBJECT_ENSURE_REGISTERED (ParfWifiManager);

TypeId

ParfWifiManager::GetTypeId (void)

{

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

    .SetParent<WifiRemoteStationManager> ()

    .SetGroupName ("Wifi")

    .AddConstructor<ParfWifiManager> ()

    .AddAttribute ("AttemptThreshold",

                   "The minimum number of transmission attempts to try a new power or rate.",

                   UintegerValue (15),

                   MakeUintegerAccessor (&ParfWifiManager::m_attemptThreshold),

                   MakeUintegerChecker<uint32_t> ())

    .AddAttribute ("SuccessThreshold",

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

                   UintegerValue (10),

                   MakeUintegerAccessor (&ParfWifiManager::m_successThreshold),

                   MakeUintegerChecker<uint32_t> ())

    .AddTraceSource ("PowerChange",

                     "The transmission power has change",

                     MakeTraceSourceAccessor (&ParfWifiManager::m_powerChange),

                     "ns3::WifiRemoteStationManager::PowerChangeTracedCallback")

    .AddTraceSource ("RateChange",

                     "The transmission rate has change",

                     MakeTraceSourceAccessor (&ParfWifiManager::m_rateChange),

                     "ns3::WifiRemoteStationManager::RateChangeTracedCallback")

  ;

  return tid;

}

ParfWifiManager::ParfWifiManager ()

{

  NS_LOG_FUNCTION (this);

}

ParfWifiManager::~ParfWifiManager ()

{

  NS_LOG_FUNCTION (this);

}

void

ParfWifiManager::SetupPhy (Ptr<WifiPhy> phy)

{

  m_minPower = phy->GetTxPowerStart ();

  m_maxPower = phy->GetTxPowerEnd ();

  WifiRemoteStationManager::SetupPhy (phy);

}

WifiRemoteStation *

ParfWifiManager::DoCreateStation (void) const

{

  NS_LOG_FUNCTION (this);

  ParfWifiRemoteStation *station = new ParfWifiRemoteStation ();

  station->m_nSuccess = 0;

  station->m_nFail = 0;

  station->m_usingRecoveryRate = false;

  station->m_usingRecoveryPower = false;

  station->m_initialized = false;

  station->m_nRetry = 0;

  station->m_nAttempt = 0;

  NS_LOG_DEBUG ("create station=" << station << ", timer=" << station->m_nAttempt

                                  << ", rate=" << station->m_currentRate << ", power=" << (int)station->m_currentPower);

  return station;

}

void

ParfWifiManager::CheckInit (ParfWifiRemoteStation *station)

{

  if (!station->m_initialized)

    {

      station->m_nSupported = GetNSupported (station);

      station->m_currentRate = station->m_nSupported - 1;

      station->m_currentPower = m_maxPower;

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

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

      station->m_initialized = true;

    }

}

void

ParfWifiManager::DoReportRtsFailed (WifiRemoteStation *station)

{

  NS_LOG_FUNCTION (this << station);

}

/**

 * \internal

 * 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 spans 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

ParfWifiManager::DoReportDataFailed (WifiRemoteStation *st)

{

  NS_LOG_FUNCTION (this << st);

  ParfWifiRemoteStation *station = (ParfWifiRemoteStation *)st;

  CheckInit (station);

  station->m_nAttempt++;

  station->m_nFail++;

  station->m_nRetry++;

  station->m_nSuccess = 0;

  NS_LOG_DEBUG ("station=" << station << " data fail retry=" << station->m_nRetry << ", timer=" << station->m_nAttempt

                           << ", rate=" << station->m_currentRate << ", power=" << (int)station->m_currentPower);

  if (station->m_usingRecoveryRate)

    {

      NS_ASSERT (station->m_nRetry >= 1);

      if (station->m_nRetry == 1)

        {

          //need recovery fallback

          if (station->m_currentRate != 0)

            {

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

              station->m_currentRate--;

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

              station->m_usingRecoveryRate = false;

            }

        }

      station->m_nAttempt = 0;

    }

  else if (station->m_usingRecoveryPower)

    {

      NS_ASSERT (station->m_nRetry >= 1);

      if (station->m_nRetry == 1)

        {

          //need recovery fallback

          if (station->m_currentPower < m_maxPower)

            {

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

              station->m_currentPower++;

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

              station->m_usingRecoveryPower = false;

            }

        }

      station->m_nAttempt = 0;

    }

  else

    {

      NS_ASSERT (station->m_nRetry >= 1);

      if (((station->m_nRetry - 1) % 2) == 1)

        {

          //need normal fallback

          if (station->m_currentPower == m_maxPower)

            {

              if (station->m_currentRate != 0)

                {

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

                  station->m_currentRate--;

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

                }

            }

          else

            {

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

              station->m_currentPower++;

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

            }

        }

      if (station->m_nRetry >= 2)

        {

          station->m_nAttempt = 0;

        }

    }

}

void

ParfWifiManager::DoReportRxOk (WifiRemoteStation *station,

                               double rxSnr, WifiMode txMode)

{

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

}

void ParfWifiManager::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 ParfWifiManager::DoReportDataOk (WifiRemoteStation *st,

                                      double ackSnr, WifiMode ackMode, double dataSnr)

{

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

  ParfWifiRemoteStation *station = (ParfWifiRemoteStation *) st;

  CheckInit (station);

  station->m_nAttempt++;

  station->m_nSuccess++;

  station->m_nFail = 0;

  station->m_usingRecoveryRate = false;

  station->m_usingRecoveryPower = false;

  station->m_nRetry = 0;

  NS_LOG_DEBUG ("station=" << station << " data ok success=" << station->m_nSuccess << ", timer=" << station->m_nAttempt << ", rate=" << station->m_currentRate << ", power=" << (int)station->m_currentPower);

  if ((station->m_nSuccess == m_successThreshold

       || station->m_nAttempt == m_attemptThreshold)

      && (station->m_currentRate < (station->m_state->m_operationalRateSet.size () - 1)))

    {

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

      station->m_currentRate++;

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

      station->m_nAttempt = 0;

      station->m_nSuccess = 0;

      station->m_usingRecoveryRate = true;

    }

  else if (station->m_nSuccess == m_successThreshold || station->m_nAttempt == m_attemptThreshold)

    {

      //we are at the maximum rate, we decrease power

      if (station->m_currentPower != m_minPower)

        {

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

          station->m_currentPower--;

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

        }

      station->m_nAttempt = 0;

      station->m_nSuccess = 0;

      station->m_usingRecoveryPower = true;

    }

}

void

ParfWifiManager::DoReportFinalRtsFailed (WifiRemoteStation *station)

{

  NS_LOG_FUNCTION (this << station);

}

void

ParfWifiManager::DoReportFinalDataFailed (WifiRemoteStation *station)

{

  NS_LOG_FUNCTION (this << station);

}

WifiTxVector

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

{

  NS_LOG_FUNCTION (this << st << size);

  ParfWifiRemoteStation *station = (ParfWifiRemoteStation *) st;

  uint32_t channelWidth = GetChannelWidth (station);

  if (channelWidth > 20 && channelWidth != 22)

    {

      //avoid to use legacy rate adaptation algorithms for IEEE 802.11n/ac

      channelWidth = 20;

    }

  CheckInit (station);

  return WifiTxVector (GetSupported (station, station->m_currentRate), station->m_currentPower, GetLongRetryCount (station), false, 1, 0, channelWidth, GetAggregation (station), false);

}

WifiTxVector

ParfWifiManager::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.

  ParfWifiRemoteStation *station = (ParfWifiRemoteStation *) st;

  uint32_t channelWidth = GetChannelWidth (station);

  if (channelWidth > 20 && channelWidth != 22)

    {

      //avoid to use legacy rate adaptation algorithms for IEEE 802.11n/ac

      channelWidth = 20;

    }

  return WifiTxVector (GetSupported (station, 0), GetDefaultTxPowerLevel (), GetShortRetryCount (station), false, 1, 0, channelWidth, GetAggregation (station), false);

}

bool

ParfWifiManager::IsLowLatency (void) const

{

  NS_LOG_FUNCTION (this);

  return true;

}

} //namespace ns3