/* -*-  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/simulator.h"

NS_LOG_COMPONENT_DEFINE ("Cara");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED(CaraWifiManager);

CaraWifiRemoteStation::CaraWifiRemoteStation (Ptr<CaraWifiManager> manager)

  : m_manager (manager)

{

  m_rate = GetMinRate ();

  m_success = 0;

  m_failed = 0;

  m_timer = 0;

}

CaraWifiRemoteStation::~CaraWifiRemoteStation ()

{}

uint32_t

CaraWifiRemoteStation::GetMaxRate (void)

{

  return GetNSupportedModes () - 1;

}

uint32_t

CaraWifiRemoteStation::GetMinRate (void)

{

  return 0;

}

bool 

CaraWifiRemoteStation::NeedNormalFallback (void)

{

  return (m_failed >= m_manager->m_failureThreshold);

}

void 

CaraWifiRemoteStation::DoReportRtsFailed (void) 

{}

void 

CaraWifiRemoteStation::DoReportDataFailed (void)

{

  NS_LOG_FUNCTION (this);

  m_timer++;

  m_failed++;

  m_success = 0;

  if (NeedNormalFallback ()) 

    {

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

      if (m_rate != GetMinRate ())

        {

          m_rate--;

        }

      m_failed = 0;

      m_timer = 0;

    }

}

void 

CaraWifiRemoteStation::DoReportRxOk (double rxSnr, WifiMode txMode)

{}

void 

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

{

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

}

void 

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

{

  m_timer++;

  m_success++;

  m_failed = 0;

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

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

       m_timer >= m_manager->m_timerTimeout))

    {

      if (m_rate < GetMaxRate ())

        {

          m_rate++;

        }

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

      m_timer = 0;

      m_success = 0;

    }

}

void 

CaraWifiRemoteStation::DoReportFinalRtsFailed (void)

{}

void 

CaraWifiRemoteStation::DoReportFinalDataFailed (void)

{}

WifiMode

CaraWifiRemoteStation::DoGetDataMode (uint32_t size)

{

  return GetSupportedMode (m_rate);

}

WifiMode

CaraWifiRemoteStation::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>

CaraWifiRemoteStation::GetManager (void) const

{

  return m_manager;

}

bool

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

{

  bool rts = WifiRemoteStation::NeedRts (packet);

  if (rts || m_failed >= m_manager->m_probeThreshold)

    {

      return true;

    }

  return false;

}

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::CreateStation (void)

{

  return new CaraWifiRemoteStation (this);

}

} // namespace ns3