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

/*

 * Copyright (c) 2008 INRIA

 * Copyright (c) 2013 Dalian University of Technology

 *

 * 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>

 *         Junling Bu <linlinjavaer@gmail.com>

 */

#include "ns3/log.h"

#include "wave-mac-low.h"

#include "higher-tx-tag.h"

namespace ns3 {

NS_LOG_COMPONENT_DEFINE ("WaveMacLow");

NS_OBJECT_ENSURE_REGISTERED (WaveMacLow);

TypeId

WaveMacLow::GetTypeId (void)

{

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

    .SetParent<MacLow> ()

    .SetGroupName ("Wave")

    .AddConstructor<WaveMacLow> ()

  ;

  return tid;

}

WaveMacLow::WaveMacLow ()

{

  NS_LOG_FUNCTION (this);

}

WaveMacLow::~WaveMacLow ()

{

  NS_LOG_FUNCTION (this);

}

void

WaveMacLow::SetWaveNetDevice (Ptr<WaveNetDevice> device)

{

  m_scheduler  =  device->GetChannelScheduler ();

  m_coordinator =  device->GetChannelCoordinator ();

  NS_ASSERT (m_scheduler != 0 && m_coordinator != 0);

}

WifiTxVector

WaveMacLow::GetDataTxVector (Ptr<const Packet> packet, const WifiMacHeader *hdr) const

{

  NS_LOG_FUNCTION (this << packet << hdr);

  HigherLayerTxVectorTag datatag;

  bool found;

  found = ConstCast<Packet> (packet)->PeekPacketTag (datatag);

  // if high layer has not controlled transmit parameters, the real transmit parameters

  // will be determined by MAC layer itself.

  if (!found)

    {

      return MacLow::GetDataTxVector (packet, hdr);

    }

  // if high layer has set the transmit parameters with non-adaption mode,

  // the real transmit parameters are determined by high layer.

  if (!datatag.IsAdaptable ())

    {

      return datatag.GetTxVector ();

    }

  // if high layer has set the transmit parameters with non-adaption mode,

  // the real transmit parameters are determined by both high layer and MAC layer.

  WifiTxVector txHigher = datatag.GetTxVector ();

  WifiTxVector txMac = MacLow::GetDataTxVector (packet, hdr);

  WifiTxVector txAdapter;

  // the DataRate set by higher layer is the minimum data rate

  // which is the lower bound for the actual data rate.

    {

      txAdapter.SetMode (txHigher.GetMode ());

    }

  else

    {

      txAdapter.SetMode (txMac.GetMode ());

    }

  // the TxPwr_Level set by higher layer is the maximum transmit

  // power which is the upper bound for the actual transmit power;

  txAdapter.SetTxPowerLevel (std::min (txHigher.GetTxPowerLevel (), txMac.GetTxPowerLevel ()));

  return txAdapter;

}

void

WaveMacLow::StartTransmission (Ptr<const Packet> packet,

                               const WifiMacHeader* hdr,

                               MacLowTransmissionParameters params,

                               MacLowTransmissionListener *listener)

{

  NS_LOG_FUNCTION (this << packet << hdr << params << listener);

  Ptr<WifiPhy> phy = MacLow::GetPhy ();

  uint32_t curChannel = phy->GetChannelNumber ();

  // if current channel access is not AlternatingAccess, just do as MacLow.

  if (!m_scheduler->IsAlternatingAccessAssigned (curChannel))

    {

      MacLow::StartTransmission (packet, hdr, params, listener);

      return;

    }

  Time transmissionTime = MacLow::CalculateTransmissionTime (packet, hdr, params);

  Time remainingTime = m_coordinator->NeedTimeToGuardInterval ();

  if (transmissionTime > remainingTime)

    {

      // The attempt for this transmission will be canceled;

      // and this packet will be pending for next transmission by EdcaTxopN class

      NS_LOG_DEBUG ("Because the required transmission time = " << transmissionTime.GetMilliSeconds ()

                                                                << "ms exceeds the remainingTime = " << remainingTime.GetMilliSeconds ()

                                                                << "ms, currently this packet will not be transmitted.");

    }

  else

    {

      MacLow::StartTransmission (packet, hdr, params, listener);

    }

}

} // namespace ns3