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

/*

 * Copyright (c) 2011,2012 Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)

 *

 * 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: Manuel Requena <manuel.requena@cttc.es>

 *         Nicola Baldo <nbaldo@cttc.es>

 */

#include "ns3/simulator.h"

#include "ns3/log.h"

#include "ns3/lte-rlc-tm.h"

#include "ns3/lte-rlc-tag.h"

NS_LOG_COMPONENT_DEFINE ("LteRlcTm");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (LteRlcTm);

LteRlcTm::LteRlcTm ()

  : m_maxTxBufferSize (0),

    m_txBufferSize (0)

{

  NS_LOG_FUNCTION (this);

  Simulator::ScheduleNow (&LteRlcTm::Start, this);

}

LteRlcTm::~LteRlcTm ()

{

}

TypeId

LteRlcTm::GetTypeId (void)

{

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

    .SetParent<LteRlc> ()

    .AddConstructor<LteRlcTm> ()

    .AddAttribute ("MaxTxBufferSize",

                   "Maximum Size of the Transmission Buffer (in Bytes)",

                   UintegerValue (2 * 1024 * 1024),

                   MakeUintegerAccessor (&LteRlcTm::m_maxTxBufferSize),

                   MakeUintegerChecker<uint32_t> ())

    ;

  return tid;

}

/**

 * RLC SAP

 */

void

LteRlcTm::DoTransmitPdcpPdu (Ptr<Packet> p)

{

  NS_LOG_FUNCTION (this << m_rnti << (uint32_t) m_lcid << p->GetSize ());

  if (m_txBufferSize + p->GetSize () <= m_maxTxBufferSize)

    {

      /** Store arrival time */

      RlcTag timeTag (Simulator::Now ());

      p->AddPacketTag (timeTag);

      NS_LOG_LOGIC ("Tx Buffer: New packet added");

      m_txBuffer.push_back (p);

      m_txBufferSize += p->GetSize ();

      NS_LOG_LOGIC ("NumOfBuffers = " << m_txBuffer.size() );

      NS_LOG_LOGIC ("txBufferSize = " << m_txBufferSize);

    }

  else

    {

      // Discard full RLC SDU

      NS_LOG_LOGIC ("TxBuffer is full. RLC SDU discarded");

      NS_LOG_LOGIC ("MaxTxBufferSize = " << m_maxTxBufferSize);

      NS_LOG_LOGIC ("txBufferSize    = " << m_txBufferSize);

      NS_LOG_LOGIC ("packet size     = " << p->GetSize ());

    }

  /** Report Buffer Status */

  DoReportBufferStatus ();

  m_rbsTimer.Cancel ();

}

/**

 * MAC SAP

 */

void

LteRlcTm::DoNotifyTxOpportunity (uint32_t bytes, uint8_t layer, uint8_t harqId)

{

  NS_LOG_FUNCTION (this << m_rnti << (uint32_t) m_lcid << bytes  << (uint32_t) layer << (uint32_t) harqId);

  // 5.1.1.1 Transmit operations 

  // 5.1.1.1.1 General

  // When submitting a new TMD PDU to lower layer, the transmitting TM RLC entity shall:

  // - submit a RLC SDU without any modification to lower layer.

  if ( m_txBuffer.size () == 0 )

    {

      NS_LOG_LOGIC ("No data pending");

      return;

    }

  Ptr<Packet> packet = (*(m_txBuffer.begin ()))->Copy ();

  if (bytes < packet->GetSize ())

    {

      // Stingy MAC: Header fix part is 2 bytes, we need more bytes for the data

      NS_LOG_WARN ("TX opportunity too small = " << bytes << " (PDU size: " << packet->GetSize () << ")");

      return;

    }

  m_txBufferSize -= (*(m_txBuffer.begin()))->GetSize ();

  m_txBuffer.erase (m_txBuffer.begin ());

  // Sender timestamp

  RlcTag rlcTag (Simulator::Now ());

  packet->AddByteTag (rlcTag);

  m_txPdu (m_rnti, m_lcid, packet->GetSize ());

  // Send RLC PDU to MAC layer

  LteMacSapProvider::TransmitPduParameters params;

  params.pdu = packet;

  params.rnti = m_rnti;

  params.lcid = m_lcid;

  params.layer = layer;

  params.harqProcessId = harqId;

  m_macSapProvider->TransmitPdu (params);

  if (! m_txBuffer.empty ())

    {

      m_rbsTimer.Cancel ();

      m_rbsTimer = Simulator::Schedule (MilliSeconds (10), &LteRlcTm::ExpireRbsTimer, this);

    }

}

void

LteRlcTm::DoNotifyHarqDeliveryFailure ()

{

  NS_LOG_FUNCTION (this);

}

void

LteRlcTm::DoReceivePdu (Ptr<Packet> p)

{

  NS_LOG_FUNCTION (this << m_rnti << (uint32_t) m_lcid << p->GetSize ());

  // Receiver timestamp

  RlcTag rlcTag;

  Time delay;

  if (p->FindFirstMatchingByteTag (rlcTag))

    {

      delay = Simulator::Now() - rlcTag.GetSenderTimestamp ();

    }

  m_rxPdu (m_rnti, m_lcid, p->GetSize (), delay.GetNanoSeconds ());

  // 5.1.1.2 Receive operations 

  // 5.1.1.2.1  General

  // When receiving a new TMD PDU from lower layer, the receiving TM RLC entity shall:

  // - deliver the TMD PDU without any modification to upper layer.

   m_rlcSapUser->ReceivePdcpPdu (p);

}

void

LteRlcTm::Start ()

{

  NS_LOG_FUNCTION (this);

  DoReportBufferStatus ();

}

void

LteRlcTm::DoReportBufferStatus (void)

{

  Time holDelay (0);

  uint32_t queueSize = 0;

  if (! m_txBuffer.empty ())

    {

      RlcTag holTimeTag;

      m_txBuffer.front ()->PeekPacketTag (holTimeTag);

      holDelay = Simulator::Now () - holTimeTag.GetSenderTimestamp ();

      queueSize = m_txBufferSize; // just data in tx queue (no header overhead for RLC TM)

    }

  LteMacSapProvider::ReportBufferStatusParameters r;

  r.rnti = m_rnti;

  r.lcid = m_lcid;

  r.txQueueSize = queueSize;

  r.txQueueHolDelay = holDelay.GetMilliSeconds () ;

  r.retxQueueSize = 0;

  r.retxQueueHolDelay = 0;

  r.statusPduSize = 0;

  NS_LOG_LOGIC ("Send ReportBufferStatus = " << r.txQueueSize << ", " << r.txQueueHolDelay );

  m_macSapProvider->ReportBufferStatus (r);

}

void

LteRlcTm::ExpireRbsTimer (void)

{

  NS_LOG_LOGIC ("RBS Timer expires");

  if (! m_txBuffer.empty ())

    {

      DoReportBufferStatus ();

      m_rbsTimer = Simulator::Schedule (MilliSeconds (10), &LteRlcTm::ExpireRbsTimer, this);

    }

}

} // namespace ns3