/* -*-  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 "cara-wifi-manager.h"

#include "ns3/assert.h"

#include "ns3/log.h"

#include "ns3/double.h"

#include "ns3/uinteger.h"

#include "ns3/simulator.h"

NS_LOG_COMPONENT_DEFINE ("Cara");

namespace ns3 {

struct CaraWifiRemoteStation : public WifiRemoteStation

{

  uint32_t m_timer;

  uint32_t m_success;

  uint32_t m_failed;  

  uint32_t m_rate;

};

NS_OBJECT_ENSURE_REGISTERED(CaraWifiManager);

TypeId 

CaraWifiManager::GetTypeId (void)

{

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

   .SetParent<WifiRemoteStationManager> ()

   .AddConstructor<CaraWifiManager> ()

   .AddAttribute ("ProbeThreshold",

                  "The number of consecutive transmissions failure to activate the RTS probe.",

                  UintegerValue (1),

                  MakeUintegerAccessor (&CaraWifiManager::m_probeThreshold),

                  MakeUintegerChecker<uint32_t> ())

   .AddAttribute ("FailureThreshold",

                  "The number of consecutive transmissions failure to decrease the rate.",

                  UintegerValue (2),

                  MakeUintegerAccessor (&CaraWifiManager::m_failureThreshold),

                  MakeUintegerChecker<uint32_t> ())

   .AddAttribute ("SuccessThreshold",

                  "The minimum number of sucessfull transmissions to try a new rate.",

                  UintegerValue (10),

                  MakeUintegerAccessor (&CaraWifiManager::m_successThreshold),

                  MakeUintegerChecker<uint32_t> ())

   .AddAttribute ("Timeout",

                  "The 'timer' in the CARA algorithm",

                  UintegerValue (15),

                  MakeUintegerAccessor (&CaraWifiManager::m_timerTimeout),

                  MakeUintegerChecker<uint32_t> ())

 ;

 return tid;

}

CaraWifiManager::CaraWifiManager ()

  : WifiRemoteStationManager ()

{}

CaraWifiManager::~CaraWifiManager ()

{}

WifiRemoteStation *

CaraWifiManager::DoCreateStation (void) const

{

  CaraWifiRemoteStation *station = new CaraWifiRemoteStation ();

  station->m_rate = 0;

  station->m_success = 0;

  station->m_failed = 0;

  station->m_timer = 0;

  return station;

}

void 

CaraWifiManager::DoReportRtsFailed (WifiRemoteStation *st)

{}

void 

CaraWifiManager::DoReportDataFailed (WifiRemoteStation *st)

{

  CaraWifiRemoteStation *station = (CaraWifiRemoteStation *) st;

  NS_LOG_FUNCTION (station);

  station->m_timer++;

  station->m_failed++;

  station->m_success = 0;

  if (station->m_failed >= m_failureThreshold) 

    {

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

      if (station->m_rate != 0)

        {

          station->m_rate--;

        }

      station->m_failed = 0;

      station->m_timer = 0;

    }

}

void 

CaraWifiManager::DoReportRxOk (WifiRemoteStation *st,

                                     double rxSnr, WifiMode txMode)

{}

void 

CaraWifiManager::DoReportRtsOk (WifiRemoteStation *st,

                                      double ctsSnr, WifiMode ctsMode, double rtsSnr)

{

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

}

void 

CaraWifiManager::DoReportDataOk (WifiRemoteStation *st,

                                       double ackSnr, WifiMode ackMode, double dataSnr)

{

  CaraWifiRemoteStation *station = (CaraWifiRemoteStation *) st;

  station->m_timer++;

  station->m_success++;

  station->m_failed = 0;

  NS_LOG_DEBUG ("self="<<station<<" data ok success="<<station->m_success<<", timer="<<station->m_timer);

  if ((station->m_success == m_successThreshold ||

       station->m_timer >= m_timerTimeout))

    {

      if (station->m_rate < GetNSupported (station) - 1)

        {

          station->m_rate++;

        }

      NS_LOG_DEBUG ("self="<<station<<" inc rate=" << station->m_rate);

      station->m_timer = 0;

      station->m_success = 0;

    }

}

void 

CaraWifiManager::DoReportFinalRtsFailed (WifiRemoteStation *st)

{}

void 

CaraWifiManager::DoReportFinalDataFailed (WifiRemoteStation *st)

{}

WifiMode

CaraWifiManager::DoGetDataMode (WifiRemoteStation *st,

                                      uint32_t size)

{

  CaraWifiRemoteStation *station = (CaraWifiRemoteStation *) st;

  return GetSupported (station, station->m_rate);

}

WifiMode

CaraWifiManager::DoGetRtsMode (WifiRemoteStation *st)

{

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

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

  return GetSupported (st, 0);

}

bool

CaraWifiManager::DoNeedRts (WifiRemoteStation *st,

                                  Ptr<const Packet> packet, bool normally)

{

  CaraWifiRemoteStation *station = (CaraWifiRemoteStation *) st;

  return normally || station->m_failed >= m_probeThreshold;

}

bool 

CaraWifiManager::IsLowLatency (void) const

{

  return true;

}

} // namespace ns3