/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2006, 2009 INRIA
 * Copyright (c) 2009 MIRKO BANCHI
 *
 * 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>
 * Author: Mirko Banchi <mk.banchi@gmail.com>
 */
#include "ns3/log.h"
#include "ns3/assert.h"

#include "edca-txop-n.h"
#include "mac-low.h"
#include "dcf-manager.h"
#include "mac-tx-middle.h"
#include "wifi-mac-trailer.h"
#include "wifi-mac.h"
#include "random-stream.h"
#include "wifi-mac-queue.h"
#include "msdu-aggregator.h"
#include "mgt-headers.h"
#include "qos-blocked-destinations.h"

NS_LOG_COMPONENT_DEFINE ("EdcaTxopN");

#undef NS_LOG_APPEND_CONTEXT
#define NS_LOG_APPEND_CONTEXT if (m_low != 0) {std::clog << "[mac=" << m_low->GetAddress () << "] ";}

namespace ns3 {

class EdcaTxopN::Dcf : public DcfState
{
public:
  Dcf (EdcaTxopN *txop)
    : m_txop (txop)
  {}
private:
  virtual void DoNotifyAccessGranted (void) {
    m_txop->NotifyAccessGranted ();
  }
  virtual void DoNotifyInternalCollision (void) {
    m_txop->NotifyInternalCollision ();
  }
  virtual void DoNotifyCollision (void) {
    m_txop->NotifyCollision ();
  }
  virtual void DoNotifyChannelSwitching (void) { 
    m_txop->NotifyChannelSwitching ();
  }
  EdcaTxopN *m_txop;
};

class EdcaTxopN::TransmissionListener : public MacLowTransmissionListener
{
public:
  TransmissionListener (EdcaTxopN *txop)
    : MacLowTransmissionListener (),
      m_txop (txop) {}
      
  virtual ~TransmissionListener () {}

  virtual void GotCts (double snr, WifiMode txMode) {
    m_txop->GotCts (snr, txMode);
  }
  virtual void MissedCts (void) {
    m_txop->MissedCts ();
  }
  virtual void GotAck (double snr, WifiMode txMode) {
    m_txop->GotAck (snr, txMode);
  }
  virtual void MissedAck (void) {
    m_txop->MissedAck ();
  }
  virtual void GotBlockAck (const CtrlBAckResponseHeader *blockAck, Mac48Address source) {
    m_txop->GotBlockAck (blockAck, source);
  }
  virtual void MissedBlockAck (void) {
    m_txop->MissedBlockAck ();
  }
  virtual void StartNext (void) {
    m_txop->StartNext ();
  }
  virtual void Cancel (void) {
    m_txop->Cancel ();
  }

private:
  EdcaTxopN *m_txop;
};

class EdcaTxopN::BlockAckEventListener : public MacLowBlockAckEventListener
{
public:
  BlockAckEventListener (EdcaTxopN *txop)
    : MacLowBlockAckEventListener (),
      m_txop (txop) {}
  virtual ~BlockAckEventListener () {}

  virtual void BlockAckInactivityTimeout (Mac48Address address, uint8_t tid) {
    m_txop->SendDelbaFrame (address, tid, false);
  }

private:
  EdcaTxopN *m_txop;
};

NS_OBJECT_ENSURE_REGISTERED (EdcaTxopN);

TypeId
EdcaTxopN::GetTypeId (void)
{
  static TypeId tid = TypeId ("ns3::EdcaTxopN")
    .SetParent (ns3::Dcf::GetTypeId ())
    .AddConstructor<EdcaTxopN> ()
    .AddAttribute ("BlockAckThreshold", "If number of packets in this queue reaches this value,\
                                         block ack mechanism is used. If this value is 0, block ack is never used.",
                   UintegerValue(0),
                   MakeUintegerAccessor (&EdcaTxopN::SetBlockAckThreshold,
                                         &EdcaTxopN::GetBlockAckThreshold),
                   MakeUintegerChecker<uint8_t> (0, 64))
    .AddAttribute ("BlockAckInactivityTimeout", "Represents max time (blocks of 1024 micro seconds) allowed for block ack\
                                                 inactivity. If this value isn't equal to 0 a timer start after that a\
                                                 block ack setup is completed and will be reset every time that a block\
                                                 ack frame is received. If this value is 0, block ack inactivity timeout won't be used.",
                   UintegerValue(0),
                   MakeUintegerAccessor (&EdcaTxopN::SetBlockAckInactivityTimeout),
                   MakeUintegerChecker<uint16_t> ())
    ;
  return tid;
}

EdcaTxopN::EdcaTxopN ()
  : m_manager (0),
    m_currentPacket(0),
    m_aggregator (0),
    m_blockAckType (COMPRESSED_BLOCK_ACK)
{
  NS_LOG_FUNCTION (this);
  m_transmissionListener = new EdcaTxopN::TransmissionListener (this);
  m_blockAckListener = new EdcaTxopN::BlockAckEventListener (this);
  m_dcf = new EdcaTxopN::Dcf (this);
  m_queue = CreateObject<WifiMacQueue> ();
  m_rng = new RealRandomStream ();
  m_qosBlockedDestinations = new QosBlockedDestinations ();
  m_baManager = new BlockAckManager ();
  m_baManager->SetQueue (m_queue);
  m_baManager->SetBlockAckType (m_blockAckType);
  m_baManager->SetBlockDestinationCallback (MakeCallback (&QosBlockedDestinations::Block, m_qosBlockedDestinations));
  m_baManager->SetUnblockDestinationCallback (MakeCallback (&QosBlockedDestinations::Unblock, m_qosBlockedDestinations));
  m_baManager->SetMaxPacketDelay (m_queue->GetMaxDelay ());
}

EdcaTxopN::~EdcaTxopN ()
{
  NS_LOG_FUNCTION (this);
}

void
EdcaTxopN::DoDispose (void)
{
  NS_LOG_FUNCTION (this);
  m_queue = 0;
  m_low = 0;
  m_stationManager = 0;
  delete m_transmissionListener;
  delete m_dcf;
  delete m_rng;
  delete m_qosBlockedDestinations;
  delete m_baManager;
  delete m_blockAckListener;
  m_transmissionListener = 0;
  m_dcf = 0;
  m_rng = 0;
  m_qosBlockedDestinations = 0;
  m_baManager = 0;
  m_blockAckListener = 0;
  m_txMiddle = 0;
  m_aggregator = 0;
}

void
EdcaTxopN::SetManager (DcfManager *manager)
{
  NS_LOG_FUNCTION (this << manager);
  m_manager = manager;
  m_manager->Add (m_dcf);
}

void
EdcaTxopN::SetTxOkCallback (TxOk callback)
{
  m_txOkCallback = callback;
}

void 
EdcaTxopN::SetTxFailedCallback (TxFailed callback)
{
  m_txFailedCallback = callback;
}

void
EdcaTxopN::SetWifiRemoteStationManager (Ptr<WifiRemoteStationManager> remoteManager)
{
  NS_LOG_FUNCTION (this << remoteManager);
  m_stationManager = remoteManager;
}
void
EdcaTxopN::SetTypeOfStation (enum TypeOfStation type)
{
  NS_LOG_FUNCTION (this << type);
  m_typeOfStation = type;
}

enum TypeOfStation
EdcaTxopN::GetTypeOfStation (void) const
{
  return m_typeOfStation;
}

void 
EdcaTxopN::SetMaxQueueSize (uint32_t size)
{
  NS_LOG_FUNCTION (this << size);
  m_queue->SetMaxSize (size);
}

void
EdcaTxopN::SetMaxQueueDelay (Time delay)
{
  NS_LOG_FUNCTION (this << delay);
  m_queue->SetMaxDelay (delay);
}

void 
EdcaTxopN::SetMinCw (uint32_t minCw)
{
  NS_LOG_FUNCTION (this << minCw);
  m_dcf->SetCwMin (minCw);
}

void 
EdcaTxopN::SetMaxCw (uint32_t maxCw)
{
  NS_LOG_FUNCTION (this << maxCw);
  m_dcf->SetCwMax (maxCw);
}

void 
EdcaTxopN::SetAifsn (uint32_t aifsn)
{
  NS_LOG_FUNCTION (this << aifsn);
  m_dcf->SetAifsn (aifsn);
}

uint32_t 
EdcaTxopN::GetMinCw (void) const
{
  return m_dcf->GetCwMin ();
}

uint32_t 
EdcaTxopN::GetMaxCw (void) const
{
  return m_dcf->GetCwMax ();
}

uint32_t 
EdcaTxopN::GetAifsn (void) const
{
  return m_dcf->GetAifsn ();
}

void
EdcaTxopN::SetTxMiddle (MacTxMiddle *txMiddle)
{
  m_txMiddle = txMiddle;
}

Ptr<MacLow>
EdcaTxopN::Low (void)
{
  return m_low;
}

void
EdcaTxopN::SetLow(Ptr<MacLow> low)
{
  NS_LOG_FUNCTION (this << low);
  m_low = low;
}

bool
EdcaTxopN::NeedsAccess (void) const
{
  return !m_queue->IsEmpty () || m_currentPacket != 0 || m_baManager->HasPackets ();
}

void
EdcaTxopN::NotifyAccessGranted (void)
{
  NS_LOG_FUNCTION (this);
  if (m_currentPacket == 0)
    {
      if (m_queue->IsEmpty () && !m_baManager->HasPackets ())
        {
          NS_LOG_DEBUG ("queue is empty");
          return; 
        }
      if (m_baManager->HasBar (m_currentBar))
        {
          SendBlockAckRequest (m_currentBar);
          return;
        }
      /* check if packets need retransmission are stored in BlockAckManager */
      m_currentPacket = m_baManager->GetNextPacket (m_currentHdr);
      if (m_currentPacket == 0)
        {
          if (m_queue->PeekFirstAvailable (&m_currentHdr, m_currentPacketTimestamp, m_qosBlockedDestinations) == 0)
            {
              NS_LOG_DEBUG ("no available packets in the queue");
              return;
            }
          if (m_currentHdr.IsQosData () && !m_currentHdr.GetAddr1 ().IsBroadcast () &&
              m_blockAckThreshold > 0 &&
              !m_baManager->ExistsAgreement (m_currentHdr.GetAddr1 (), m_currentHdr.GetQosTid ()) &&
              SetupBlockAckIfNeeded ())
            {
              return;
            }
          m_currentPacket = m_queue->DequeueFirstAvailable (&m_currentHdr, m_currentPacketTimestamp, m_qosBlockedDestinations);
          NS_ASSERT (m_currentPacket != 0);
          
          uint16_t sequence = m_txMiddle->GetNextSequenceNumberfor (&m_currentHdr);
          m_currentHdr.SetSequenceNumber (sequence);
          m_currentHdr.SetFragmentNumber (0);
          m_currentHdr.SetNoMoreFragments ();
          m_currentHdr.SetNoRetry ();
          m_fragmentNumber = 0;
          NS_LOG_DEBUG ("dequeued size="<<m_currentPacket->GetSize ()<<
                    ", to="<<m_currentHdr.GetAddr1 ()<<
                    ", seq="<<m_currentHdr.GetSequenceControl ());
          if (m_currentHdr.IsQosData () && !m_currentHdr.GetAddr1 ().IsBroadcast ())
            {
              VerifyBlockAck ();
            }
        }
    }
  MacLowTransmissionParameters params;
  params.DisableOverrideDurationId ();
  if (m_currentHdr.GetAddr1 ().IsGroup ()) 
    {
      params.DisableRts ();
      params.DisableAck ();
      params.DisableNextData ();
      m_low->StartTransmission (m_currentPacket,
                                &m_currentHdr,
                                params,
                                m_transmissionListener);
      
      m_currentPacket = 0;
      m_dcf->ResetCw ();
      m_dcf->StartBackoffNow (m_rng->GetNext (0, m_dcf->GetCw ()));
      StartAccessIfNeeded ();
      NS_LOG_DEBUG ("tx broadcast");
    }
  else if (m_currentHdr.GetType() == WIFI_MAC_CTL_BACKREQ)
    {
      SendBlockAckRequest (m_currentBar);
    }
  else
    {
      if (m_currentHdr.IsQosData () && m_currentHdr.IsQosBlockAck ())
        {
          params.DisableAck ();
        }
      else
        {
          params.EnableAck ();
        }
      if (NeedFragmentation () && ((m_currentHdr.IsQosData () && 
                                   !m_currentHdr.IsQosAmsdu ()) ||
                                   m_currentHdr.IsData ()) &&
                                  (m_blockAckThreshold == 0 ||
                                   m_blockAckType == BASIC_BLOCK_ACK))
        {
          //With COMPRESSED_BLOCK_ACK fragmentation must be avoided.
          params.DisableRts ();
          WifiMacHeader hdr;
          Ptr<Packet> fragment = GetFragmentPacket (&hdr);
          if (IsLastFragment ()) 
            {
              NS_LOG_DEBUG ("fragmenting last fragment size=" << fragment->GetSize ());
              params.DisableNextData ();
            } 
          else 
            {
              NS_LOG_DEBUG ("fragmenting size=" << fragment->GetSize ());
              params.EnableNextData (GetNextFragmentSize ());
            }
          m_low->StartTransmission (fragment, &hdr, params, 
                                    m_transmissionListener);
        }
      else
        {
          WifiMacHeader peekedHdr;
          if (m_currentHdr.IsQosData () &&
              m_queue->PeekByTidAndAddress (&peekedHdr, m_currentHdr.GetQosTid (), 
                                            WifiMacHeader::ADDR1, m_currentHdr.GetAddr1 ()) &&
              !m_currentHdr.GetAddr1 ().IsBroadcast () &&
              m_aggregator != 0 && !m_currentHdr.IsRetry ())
            {
              /* here is performed aggregation */
              Ptr<Packet> currentAggregatedPacket = Create<Packet> ();
              m_aggregator->Aggregate (m_currentPacket, currentAggregatedPacket,
                                       MapSrcAddressForAggregation (peekedHdr),
                                       MapDestAddressForAggregation (peekedHdr));
              bool aggregated = false;
              bool isAmsdu = false;
              Ptr<const Packet> peekedPacket = m_queue->PeekByTidAndAddress (&peekedHdr, m_currentHdr.GetQosTid (), 
                                                                             WifiMacHeader::ADDR1, 
                                                                             m_currentHdr.GetAddr1 ());
              while (peekedPacket != 0)
                {
                  aggregated = m_aggregator->Aggregate (peekedPacket, currentAggregatedPacket,
                                                        MapSrcAddressForAggregation (peekedHdr),
                                                        MapDestAddressForAggregation (peekedHdr));
                  if (aggregated) 
                    {
                      isAmsdu = true;
                      m_queue->Remove (peekedPacket);
                    }
                  else
                    {
                      break;
                    }
                  peekedPacket = m_queue->PeekByTidAndAddress (&peekedHdr, m_currentHdr.GetQosTid (), 
                                                               WifiMacHeader::ADDR1, m_currentHdr.GetAddr1 ());
                }
              if (isAmsdu)
                {
                  m_currentHdr.SetQosAmsdu ();
                  m_currentHdr.SetAddr3 (m_low->GetBssid ());
                  m_currentPacket = currentAggregatedPacket;
                  currentAggregatedPacket = 0;
                  NS_LOG_DEBUG ("tx unicast A-MSDU");
                }
            }
          if (NeedRts ())
            {
              params.EnableRts ();
              NS_LOG_DEBUG ("tx unicast rts");
            } 
          else 
            {
              params.DisableRts ();
              NS_LOG_DEBUG ("tx unicast");
            }
          params.DisableNextData ();
          m_low->StartTransmission (m_currentPacket, &m_currentHdr,
                                    params, m_transmissionListener);
          CompleteTx ();
        }
    }
}

void EdcaTxopN::NotifyInternalCollision (void)
{
  NS_LOG_FUNCTION (this);
  NotifyCollision ();
}

void
EdcaTxopN::NotifyCollision (void)
{
  NS_LOG_FUNCTION (this);
  m_dcf->StartBackoffNow (m_rng->GetNext (0, m_dcf->GetCw ()));
  RestartAccessIfNeeded ();
}

void 
EdcaTxopN::GotCts (double snr, WifiMode txMode)
{
  NS_LOG_FUNCTION (this << snr << txMode);
  NS_LOG_DEBUG ("got cts");
}

void 
EdcaTxopN::MissedCts (void)
{
  NS_LOG_FUNCTION (this);
  NS_LOG_DEBUG ("missed cts");
  if (!NeedRtsRetransmission ())
    {
      NS_LOG_DEBUG ("Cts Fail");
      m_stationManager->ReportFinalRtsFailed (m_currentHdr.GetAddr1 (), &m_currentHdr);
      if (!m_txFailedCallback.IsNull ()) 
        {
          m_txFailedCallback (m_currentHdr);
        }
      // to reset the dcf.
      m_currentPacket = 0;
      m_dcf->ResetCw ();
    } 
  else 
    {
      m_dcf->UpdateFailedCw ();
    }
  m_dcf->StartBackoffNow (m_rng->GetNext (0, m_dcf->GetCw ()));
  RestartAccessIfNeeded ();
}

void 
EdcaTxopN::NotifyChannelSwitching (void)
{
  m_queue->Flush();
  m_currentPacket = 0;
}

void
EdcaTxopN::Queue (Ptr<const Packet> packet, const WifiMacHeader &hdr)
{
  NS_LOG_FUNCTION (this << packet << &hdr);
  WifiMacTrailer fcs;
  uint32_t fullPacketSize = hdr.GetSerializedSize () + packet->GetSize () + fcs.GetSerializedSize ();
  m_stationManager->PrepareForQueue (hdr.GetAddr1 (), &hdr,
                                     packet, fullPacketSize);
  m_queue->Enqueue (packet, hdr);
  StartAccessIfNeeded ();
}

void
EdcaTxopN::GotAck (double snr, WifiMode txMode)
{
  NS_LOG_FUNCTION (this << snr << txMode);
  if (!NeedFragmentation () ||
      IsLastFragment () ||
      m_currentHdr.IsQosAmsdu ()) 
    {
      NS_LOG_DEBUG ("got ack. tx done.");
      if (!m_txOkCallback.IsNull ())
        {
           m_txOkCallback (m_currentHdr);
        }
      
      if (m_currentHdr.IsAction ())
        {
          WifiActionHeader actionHdr;
          Ptr<Packet> p = m_currentPacket->Copy ();
          p->RemoveHeader (actionHdr);
          if (actionHdr.GetCategory () == WifiActionHeader::BLOCK_ACK &&
              actionHdr.GetAction ().blockAck == WifiActionHeader::BLOCK_ACK_DELBA)
            {
              MgtDelBaHeader delBa;
              p->PeekHeader (delBa);
              if (delBa.IsByOriginator ())
                {
                  m_baManager->TearDownBlockAck (m_currentHdr.GetAddr1 (), delBa.GetTid ());
                }
              else
                {
                  m_low->DestroyBlockAckAgreement (m_currentHdr.GetAddr1 (), delBa.GetTid ());
                }
            }
        }
      m_currentPacket = 0;
         
      m_dcf->ResetCw ();
      m_dcf->StartBackoffNow (m_rng->GetNext (0, m_dcf->GetCw ()));
      RestartAccessIfNeeded ();
    } 
  else 
    {
      NS_LOG_DEBUG ("got ack. tx not done, size="<<m_currentPacket->GetSize ());
    }
}

void
EdcaTxopN::MissedAck (void)
{
  NS_LOG_FUNCTION (this);
  NS_LOG_DEBUG ("missed ack");
  if (!NeedDataRetransmission ()) 
    {
      NS_LOG_DEBUG ("Ack Fail");
      m_stationManager->ReportFinalDataFailed (m_currentHdr.GetAddr1 (), &m_currentHdr);
      if (!m_txFailedCallback.IsNull ()) 
        {
          m_txFailedCallback (m_currentHdr);
        }
      // to reset the dcf.
      m_currentPacket = 0;
      m_dcf->ResetCw ();
    } 
  else 
    {
      NS_LOG_DEBUG ("Retransmit");
      m_currentHdr.SetRetry ();
      m_dcf->UpdateFailedCw ();
    }
  m_dcf->StartBackoffNow (m_rng->GetNext (0, m_dcf->GetCw ()));
  RestartAccessIfNeeded ();
}

void
EdcaTxopN::MissedBlockAck (void)
{
  NS_LOG_FUNCTION (this);
  NS_LOG_DEBUG ("missed block ack");
  //should i report this to station addressed by ADDR1?
  NS_LOG_DEBUG ("Retransmit block ack request");
  m_currentHdr.SetRetry ();
  m_dcf->UpdateFailedCw ();
  
  m_dcf->StartBackoffNow (m_rng->GetNext (0, m_dcf->GetCw ()));
  RestartAccessIfNeeded ();
}

Ptr<MsduAggregator>
EdcaTxopN::GetMsduAggregator (void) const
{
  return m_aggregator;
}

void
EdcaTxopN::RestartAccessIfNeeded (void)
{
  NS_LOG_FUNCTION (this);
  if ((m_currentPacket != 0 ||
       !m_queue->IsEmpty () || m_baManager->HasPackets ()) &&
       !m_dcf->IsAccessRequested ())
    {
      m_manager->RequestAccess (m_dcf);
    }
}

void
EdcaTxopN::StartAccessIfNeeded (void)
{
  NS_LOG_FUNCTION (this);
  if (m_currentPacket == 0 &&
      (!m_queue->IsEmpty () || m_baManager->HasPackets ()) &&
      !m_dcf->IsAccessRequested ())
    {
      m_manager->RequestAccess (m_dcf);
    }
}

bool
EdcaTxopN::NeedRts (void)
{
  return m_stationManager->NeedRts (m_currentHdr.GetAddr1 (), &m_currentHdr,
                                    m_currentPacket);
}

bool
EdcaTxopN::NeedRtsRetransmission (void)
{
  return m_stationManager->NeedRtsRetransmission (m_currentHdr.GetAddr1 (), &m_currentHdr,
                                                  m_currentPacket);
}

bool
EdcaTxopN::NeedDataRetransmission (void)
{
  return m_stationManager->NeedDataRetransmission (m_currentHdr.GetAddr1 (), &m_currentHdr,
                                                   m_currentPacket);
}

void
EdcaTxopN::NextFragment (void)
{
  m_fragmentNumber++;
}

void 
EdcaTxopN::StartNext (void)
{
  NS_LOG_FUNCTION (this);
  NS_LOG_DEBUG ("start next packet fragment");
  /* this callback is used only for fragments. */
  NextFragment ();
  WifiMacHeader hdr;
  Ptr<Packet> fragment = GetFragmentPacket (&hdr);
  MacLowTransmissionParameters params;
  params.EnableAck ();
  params.DisableRts ();
  params.DisableOverrideDurationId ();
  if (IsLastFragment ()) 
    {
      params.DisableNextData ();
    } 
  else 
    {
      params.EnableNextData (GetNextFragmentSize ());
    }
  Low ()->StartTransmission (fragment, &hdr, params, m_transmissionListener);
}

void
EdcaTxopN::Cancel (void)
{
  NS_LOG_FUNCTION (this);
  NS_LOG_DEBUG ("transmission cancelled");
}

bool
EdcaTxopN::NeedFragmentation (void) const
{
  return m_stationManager->NeedFragmentation (m_currentHdr.GetAddr1 (), &m_currentHdr,
                                              m_currentPacket);
}

uint32_t
EdcaTxopN::GetFragmentSize (void)
{
  return m_stationManager->GetFragmentSize (m_currentHdr.GetAddr1 (), &m_currentHdr,
                                            m_currentPacket, m_fragmentNumber);
}

uint32_t
EdcaTxopN::GetNextFragmentSize (void) 
{
  return m_stationManager->GetFragmentSize (m_currentHdr.GetAddr1 (), &m_currentHdr,
                                            m_currentPacket, m_fragmentNumber + 1);
}

uint32_t
EdcaTxopN::GetFragmentOffset (void) 
{
  return m_stationManager->GetFragmentOffset (m_currentHdr.GetAddr1 (), &m_currentHdr,
                                              m_currentPacket, m_fragmentNumber);
}


bool
EdcaTxopN::IsLastFragment (void) const
{
  return m_stationManager->IsLastFragment (m_currentHdr.GetAddr1 (), &m_currentHdr,
                                           m_currentPacket, m_fragmentNumber);
}

Ptr<Packet>
EdcaTxopN::GetFragmentPacket (WifiMacHeader *hdr)
{
  *hdr = m_currentHdr;
  hdr->SetFragmentNumber (m_fragmentNumber);
  uint32_t startOffset = GetFragmentOffset ();
  Ptr<Packet> fragment;
  if (IsLastFragment ()) 
    {
      hdr->SetNoMoreFragments ();
    } 
  else 
    {
      hdr->SetMoreFragments ();
    }
  fragment = m_currentPacket->CreateFragment (startOffset, 
                                              GetFragmentSize ());
  return fragment;
}

void
EdcaTxopN::SetAccessCategory (enum AcIndex ac)
{
  m_ac = ac;
}

Mac48Address
EdcaTxopN::MapSrcAddressForAggregation (const WifiMacHeader &hdr)
{
  Mac48Address retval;
  if (m_typeOfStation == STA || m_typeOfStation == ADHOC_STA)
    {
      retval = hdr.GetAddr2 ();
    }
  else
    {
      retval = hdr.GetAddr3 ();
    }
  return retval;
}

Mac48Address
EdcaTxopN::MapDestAddressForAggregation (const WifiMacHeader &hdr)
{
  Mac48Address retval;
  if (m_typeOfStation == AP || m_typeOfStation == ADHOC_STA)
    {
      retval = hdr.GetAddr1 ();
    }
  else
    {
      retval = hdr.GetAddr3 ();
    }
  return retval;
}

void
EdcaTxopN::SetMsduAggregator (Ptr<MsduAggregator> aggr)
{
  m_aggregator = aggr;
}

void
EdcaTxopN::PushFront (Ptr<const Packet> packet, const WifiMacHeader &hdr)
{
  NS_LOG_FUNCTION (this << packet << &hdr);
  WifiMacTrailer fcs;
  uint32_t fullPacketSize = hdr.GetSerializedSize () + packet->GetSize () + fcs.GetSerializedSize ();
  m_stationManager->PrepareForQueue (hdr.GetAddr1 (), &hdr,
                                     packet, fullPacketSize);
  m_queue->PushFront (packet, hdr);
  StartAccessIfNeeded ();
}

void
EdcaTxopN::GotAddBaResponse (const MgtAddBaResponseHeader *respHdr, Mac48Address recipient)
{
  NS_LOG_FUNCTION (this);
  NS_LOG_DEBUG ("received ADDBA response from "<<recipient);
  uint8_t tid = respHdr->GetTid ();
  if (m_baManager->ExistsAgreementInState (recipient, tid, OriginatorBlockAckAgreement::PENDING))
   {
     if (respHdr->GetStatusCode ().IsSuccess ())
       {
         NS_LOG_DEBUG ("block ack agreement established with "<<recipient);
         m_baManager->UpdateAgreement (respHdr, recipient);
       }
     else
       {
         NS_LOG_DEBUG ("discard ADDBA response"<<recipient);
         m_baManager->NotifyAgreementUnsuccessful (recipient, tid);
       }
    }
  RestartAccessIfNeeded ();
}

void
EdcaTxopN::GotDelBaFrame (const MgtDelBaHeader *delBaHdr, Mac48Address recipient)
{
  NS_LOG_FUNCTION (this);
  NS_LOG_DEBUG ("received DELBA frame from="<<recipient);
  m_baManager->TearDownBlockAck (recipient, delBaHdr->GetTid ());
}

void
EdcaTxopN::GotBlockAck (const CtrlBAckResponseHeader *blockAck, Mac48Address recipient)
{
  NS_LOG_DEBUG ("got block ack from="<<recipient);
  m_baManager->NotifyGotBlockAck (blockAck, recipient);
  m_currentPacket = 0;
  m_dcf->ResetCw ();
  m_dcf->StartBackoffNow (m_rng->GetNext (0, m_dcf->GetCw ()));
  RestartAccessIfNeeded ();
}

void
EdcaTxopN::VerifyBlockAck (void)
{
  NS_LOG_FUNCTION (this);
  uint8_t tid = m_currentHdr.GetQosTid ();
  Mac48Address recipient = m_currentHdr.GetAddr1 ();
  uint16_t sequence = m_currentHdr.GetSequenceNumber ();
  if (m_baManager->ExistsAgreementInState (recipient, tid, OriginatorBlockAckAgreement::INACTIVE))
    {
      m_baManager->SwitchToBlockAckIfNeeded (recipient, tid, sequence);
    }
  if (m_baManager->ExistsAgreementInState (recipient, tid, OriginatorBlockAckAgreement::ESTABLISHED))
    {
      m_currentHdr.SetQosAckPolicy (WifiMacHeader::BLOCK_ACK);
    }
}

void
EdcaTxopN::CompleteTx (void)
{
  if (m_currentHdr.IsQosData () && m_currentHdr.IsQosBlockAck ())
    {
      if (!m_currentHdr.IsRetry ())
        {
          m_baManager->StorePacket (m_currentPacket, m_currentHdr, m_currentPacketTimestamp);
        }
      m_baManager->NotifyMpduTransmission (m_currentHdr.GetAddr1 (), m_currentHdr.GetQosTid ());
      //we are not waiting for an ack: transmission is completed
      m_currentPacket = 0;
      m_dcf->ResetCw ();
      m_dcf->StartBackoffNow (m_rng->GetNext (0, m_dcf->GetCw ()));
      StartAccessIfNeeded ();
    }
}

bool
EdcaTxopN::SetupBlockAckIfNeeded ()
{
  uint8_t tid = m_currentHdr.GetQosTid ();
  Mac48Address recipient = m_currentHdr.GetAddr1 ();

  uint32_t packets = m_queue->GetNPacketsByTidAndAddress (tid, WifiMacHeader::ADDR1, recipient);

  if (packets >= m_blockAckThreshold)
    {
      /* Block ack setup */
      uint16_t startingSequence = m_txMiddle->GetNextSeqNumberByTidAndAddress (tid, recipient);
      SendAddBaRequest (recipient, tid, startingSequence, m_blockAckInactivityTimeout, true);
      return true;
    }
  return false;
}

void
EdcaTxopN::SendBlockAckRequest (const struct Bar &bar)
{
  NS_LOG_FUNCTION (this);
  WifiMacHeader hdr;
  hdr.SetType (WIFI_MAC_CTL_BACKREQ);
  hdr.SetAddr1 (bar.recipient);
  hdr.SetAddr2 (m_low->GetAddress ());
  hdr.SetAddr3 (m_low->GetBssid ());
  hdr.SetDsNotTo ();
  hdr.SetDsNotFrom ();
  hdr.SetNoRetry ();
  hdr.SetNoMoreFragments ();

  m_currentPacket = bar.bar;
  m_currentHdr = hdr;

  MacLowTransmissionParameters params;
  params.DisableRts ();
  params.DisableNextData ();
  params.DisableOverrideDurationId ();
  if (bar.immediate)
    {
      if (m_blockAckType == BASIC_BLOCK_ACK)
        {
          params.EnableBasicBlockAck ();
        }
      else if (m_blockAckType == COMPRESSED_BLOCK_ACK)
        {
          params.EnableCompressedBlockAck ();
        }
      else if (m_blockAckType == MULTI_TID_BLOCK_ACK)
        {
          NS_FATAL_ERROR ("Multi-tid block ack is not supported");
        }
    }
  else
    {
      //Delayed block ack
      params.EnableAck ();
    }
  m_low->StartTransmission (m_currentPacket, &m_currentHdr, params, m_transmissionListener);
}

void
EdcaTxopN::CompleteConfig (void)
{
  NS_LOG_FUNCTION (this);
  m_baManager->SetTxMiddle (m_txMiddle);
  m_low->RegisterBlockAckListenerForAc (m_ac, m_blockAckListener);
  m_baManager->SetBlockAckInactivityCallback (MakeCallback (&EdcaTxopN::SendDelbaFrame, this));
}

void
EdcaTxopN::SetBlockAckThreshold (uint8_t threshold)
{
  m_blockAckThreshold = threshold;
  m_baManager->SetBlockAckThreshold (threshold);
}

void
EdcaTxopN::SetBlockAckInactivityTimeout (uint16_t timeout)
{
  m_blockAckInactivityTimeout = timeout;
}

uint8_t
EdcaTxopN::GetBlockAckThreshold (void) const
{
  return m_blockAckThreshold;
}

void
EdcaTxopN::SendAddBaRequest (Mac48Address dest, uint8_t tid, uint16_t startSeq, 
                             uint16_t timeout, bool immediateBAck)
{
  NS_LOG_FUNCTION (this);
  NS_LOG_DEBUG ("sent ADDBA request to "<<dest);
  WifiMacHeader hdr;
  hdr.SetAction ();
  hdr.SetAddr1 (dest);
  hdr.SetAddr2 (m_low->GetAddress ());
  hdr.SetAddr3 (m_low->GetAddress ());
  hdr.SetDsNotTo ();
  hdr.SetDsNotFrom ();
  
  WifiActionHeader actionHdr;
  WifiActionHeader::ActionValue action;
  action.blockAck = WifiActionHeader::BLOCK_ACK_ADDBA_REQUEST;
  actionHdr.SetAction (WifiActionHeader::BLOCK_ACK, action);

  Ptr<Packet> packet = Create<Packet> ();
  /*Setting ADDBARequest header*/
  MgtAddBaRequestHeader reqHdr;
  reqHdr.SetAmsduSupport (true);
  if (immediateBAck)
    {
      reqHdr.SetImmediateBlockAck ();
    }
  else
    {
      reqHdr.SetDelayedBlockAck ();
    }
  reqHdr.SetTid (tid);
  /* For now we don't use buffer size field in the ADDBA request frame. The recipient
   * will choose how many packets it can receive under block ack.
   */
  reqHdr.SetBufferSize (0);
  reqHdr.SetTimeout (timeout);
  reqHdr.SetStartingSequence (startSeq);

  m_baManager->CreateAgreement (&reqHdr, dest);
  
  packet->AddHeader (reqHdr);
  packet->AddHeader (actionHdr);
  
  m_currentPacket = packet;
  m_currentHdr = hdr;

  uint16_t sequence = m_txMiddle->GetNextSequenceNumberfor (&m_currentHdr);
  m_currentHdr.SetSequenceNumber (sequence);
  m_currentHdr.SetFragmentNumber (0);
  m_currentHdr.SetNoMoreFragments ();
  m_currentHdr.SetNoRetry ();
  
  MacLowTransmissionParameters params;
  params.EnableAck ();
  params.DisableRts ();
  params.DisableNextData ();
  params.DisableOverrideDurationId ();
  
  m_low->StartTransmission (m_currentPacket, &m_currentHdr, params, 
                            m_transmissionListener);
}

void
EdcaTxopN::SendDelbaFrame (Mac48Address addr, uint8_t tid, bool byOriginator)
{
  WifiMacHeader hdr;
  hdr.SetAction ();
  hdr.SetAddr1 (addr);
  hdr.SetAddr2 (m_low->GetAddress ());
  hdr.SetAddr3 (m_low->GetAddress ());
  hdr.SetDsNotTo ();
  hdr.SetDsNotFrom ();

  MgtDelBaHeader delbaHdr;
  delbaHdr.SetTid (tid);
  if (byOriginator)
    {
      delbaHdr.SetByOriginator ();
    }
  else
    {
      delbaHdr.SetByRecipient ();
    }

  WifiActionHeader actionHdr;
  WifiActionHeader::ActionValue action;
  action.blockAck = WifiActionHeader::BLOCK_ACK_DELBA;
  actionHdr.SetAction (WifiActionHeader::BLOCK_ACK, action);
  
  Ptr<Packet> packet = Create<Packet> ();
  packet->AddHeader (delbaHdr);
  packet->AddHeader (actionHdr);

  PushFront (packet, hdr);
}
void
EdcaTxopN::DoStart ()
{
  m_dcf->ResetCw ();
  m_dcf->StartBackoffNow (m_rng->GetNext (0, m_dcf->GetCw ()));
  ns3::Dcf::DoStart ();
}
} //namespace ns3
