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

/*

 * Copyright (c) 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: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 */

#include "ideal-wifi-manager.h"

#include "wifi-phy.h"

#include "ns3/assert.h"

#include "ns3/double.h"

#include <math.h>

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (IdealWifiManager);

TypeId 

IdealWifiManager::GetTypeId (void)

{

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

    .SetParent<WifiRemoteStationManager> ()

    .AddConstructor<IdealWifiManager> ()

    .AddAttribute ("BerThreshold",

                   "The maximum Bit Error Rate acceptable at any transmission mode",

                   DoubleValue (10e-6),

                   MakeDoubleAccessor (&IdealWifiManager::m_ber),

                   MakeDoubleChecker<double> ())

    ;

  return tid;

}

IdealWifiManager::IdealWifiManager ()

{}

IdealWifiManager::~IdealWifiManager ()

{}

void 

IdealWifiManager::SetupPhy (Ptr<WifiPhy> phy)

{

  uint32_t nModes = phy->GetNModes ();

  for (uint32_t i = 0; i < nModes; i++) 

    {

      WifiMode mode = phy->GetMode (i);

      AddModeSnrThreshold (mode, phy->CalculateSnr (mode, m_ber));

    }

  WifiRemoteStationManager::SetupPhy (phy);

}

WifiRemoteStation *

IdealWifiManager::CreateStation (void)

{

  return new IdealWifiRemoteStation (this);

}

double 

IdealWifiManager::GetSnrThreshold (WifiMode mode) const

{

  for (Thresholds::const_iterator i = m_thresholds.begin (); i != m_thresholds.end (); i++) 

    {

      if (mode == i->second)

        {

          return i->first;

        }

    }

  NS_ASSERT (false);

  return 0.0;

}

void 

IdealWifiManager::AddModeSnrThreshold (WifiMode mode, double snr)

{

  m_thresholds.push_back (std::make_pair (snr,mode));

}

IdealWifiRemoteStation::IdealWifiRemoteStation (Ptr<IdealWifiManager> manager)

  : m_manager (manager),

    m_lastSnr (0.0)

{}

IdealWifiRemoteStation::~IdealWifiRemoteStation ()

{}

void 

IdealWifiRemoteStation::DoReportRxOk (double rxSnr, WifiMode txMode)

{}

void 

IdealWifiRemoteStation::DoReportRtsFailed (void)

{}

void 

IdealWifiRemoteStation::DoReportDataFailed (void)

{}

void 

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

{

  m_lastSnr = rtsSnr;

}

void 

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

{

  m_lastSnr = dataSnr;

}

void 

IdealWifiRemoteStation::DoReportFinalRtsFailed (void)

{}

void 

IdealWifiRemoteStation::DoReportFinalDataFailed (void)

{}

WifiMode

IdealWifiRemoteStation::DoGetDataMode (uint32_t size)

{

  // We search within the Supported rate set the mode with the 

  // highest snr threshold possible which is smaller than m_lastSnr 

  // to ensure correct packet delivery.

  double maxThreshold = 0.0;

  WifiMode maxMode = m_manager->GetDefaultMode ();

  for (uint32_t i = 0; i < GetNSupportedModes (); i++)

    {

      WifiMode mode = GetSupportedMode (i);

      double threshold = m_manager->GetSnrThreshold (mode);

      if (threshold > maxThreshold && 

          threshold < m_lastSnr)

        {

          maxThreshold = threshold;

          maxMode = mode;

        }

    }

  return maxMode;

}

WifiMode

IdealWifiRemoteStation::DoGetRtsMode (void)

{

  // We search within the Basic rate set the mode with the highest 

  // snr threshold possible which is smaller than m_lastSnr to 

  // ensure correct packet delivery.

  double maxThreshold = 0.0;

  WifiMode maxMode = m_manager->GetDefaultMode ();

  for (uint32_t i = 0; i < m_manager->GetNBasicModes (); i++)

    {

      WifiMode mode = m_manager->GetBasicMode (i);

      double threshold = m_manager->GetSnrThreshold (mode);

      if (threshold > maxThreshold && 

          threshold < m_lastSnr)

        {

          maxThreshold = threshold;

          maxMode = mode;

        }

    }

  return maxMode;

}

Ptr<WifiRemoteStationManager>

IdealWifiRemoteStation::GetManager (void) const

{

  return m_manager;

}

} // namespace ns3