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

/*

 * Copyright (c) 2011 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>

 */

#ifndef LTE_RLC_AM_H

#define LTE_RLC_AM_H

#include <ns3/event-id.h>

#include <ns3/lte-rlc-sequence-number.h>

#include <ns3/lte-rlc.h>

#include <vector>

#include <map>

namespace ns3 {

/**

 * LTE RLC Acknowledged Mode (AM), see 3GPP TS 36.322

 */

class LteRlcAm : public LteRlc

{

public:

  LteRlcAm ();

  virtual ~LteRlcAm ();

  static TypeId GetTypeId (void);

  virtual void DoDispose ();

  /**

   * RLC SAP

   */

  virtual void DoTransmitPdcpPdu (Ptr<Packet> p);

  /**

   * MAC SAP

   */

  virtual void DoNotifyTxOpportunity (uint32_t bytes, uint8_t layer, uint8_t harqId);

  virtual void DoNotifyHarqDeliveryFailure ();

  virtual void DoReceivePdu (Ptr<Packet> p);

private:

  /**

   * This method will schedule a timeout at WaitReplyTimeout interval

   * in the future, unless a timer is already running for the cache,

   * in which case this method does nothing.

   */

  void ExpireReorderingTimer (void);

  void ExpirePollRetransmitTimer (void);

  void ExpireRbsTimer (void);

  /** 

   * method called when the T_status_prohibit timer expires

   * 

   */

  void ExpireStatusProhibitTimer (void);

  bool IsInsideReceivingWindow (SequenceNumber10 seqNumber);

// 

//   void ReassembleOutsideWindow (void);

//   void ReassembleSnLessThan (uint16_t seqNumber);

// 

  void ReassembleAndDeliver (Ptr<Packet> packet);

  void DoReportBufferStatus ();

private:

    std::vector < Ptr<Packet> > m_txonBuffer;       // Transmission buffer

    struct RetxPdu

    {

      Ptr<Packet> m_pdu;

      uint16_t    m_retxCount;

    };

  std::vector <RetxPdu> m_txedBuffer;  ///< Buffer for transmitted and retransmitted PDUs 

                                       ///< that have not been acked but are not considered 

                                       ///< for retransmission 

  std::vector <RetxPdu> m_retxBuffer;  ///< Buffer for PDUs considered for retransmission

    uint32_t m_txonBufferSize;

    uint32_t m_retxBufferSize;

    uint32_t m_txedBufferSize;

    bool     m_statusPduRequested;

    uint32_t m_statusPduBufferSize;

    struct PduBuffer

    {

      SequenceNumber10  m_seqNumber;

      std::list < Ptr<Packet> >  m_byteSegments;

      bool      m_pduComplete;

    };

    std::map <uint16_t, PduBuffer > m_rxonBuffer; // Reception buffer

    Ptr<Packet> m_controlPduBuffer;               // Control PDU buffer (just one PDU)

    // SDU reassembly

//   std::vector < Ptr<Packet> > m_reasBuffer;     // Reassembling buffer

// 

    std::list < Ptr<Packet> > m_sdusBuffer;       // List of SDUs in a packet (PDU)

  /**

   * State variables. See section 7.1 in TS 36.322

   */

  // Transmitting side

  SequenceNumber10 m_vtA;                   // VT(A)

  SequenceNumber10 m_vtMs;                  // VT(MS)

  SequenceNumber10 m_vtS;                   // VT(S)

  SequenceNumber10 m_pollSn;                // POLL_SN

  // Receiving side

  SequenceNumber10 m_vrR;                   // VR(R)

  SequenceNumber10 m_vrMr;                  // VR(MR)

  SequenceNumber10 m_vrX;                   // VR(X)

  SequenceNumber10 m_vrMs;                  // VR(MS)

  SequenceNumber10 m_vrH;                   // VR(H)

  /**

   * Counters. See section 7.1 in TS 36.322

   */

  uint32_t m_pduWithoutPoll;

  uint32_t m_byteWithoutPoll;

  /**

   * Constants. See section 7.2 in TS 36.322

   */

  uint16_t m_windowSize;

  /**

   * Timers. See section 7.3 in TS 36.322

   */

  EventId m_pollRetransmitTimer;

  Time    m_pollRetransmitTimerValue;

  EventId m_reorderingTimer;

  Time    m_reorderingTimerValue;

  EventId m_statusProhibitTimer;

  Time    m_statusProhibitTimerValue;

  EventId m_rbsTimer;

  Time    m_rbsTimerValue;

  /**

   * Configurable parameters. See section 7.4 in TS 36.322

   */

  uint16_t m_maxRetxThreshold;  /// \todo How these parameters are configured???

  uint16_t m_pollPdu;

  uint16_t m_pollByte;

  bool m_txOpportunityForRetxAlwaysBigEnough;

  bool m_pollRetransmitTimerJustExpired;

  /**

   * SDU Reassembling state

   */

  typedef enum { NONE            = 0,

                 WAITING_S0_FULL = 1,

                 WAITING_SI_SF   = 2 } ReassemblingState_t;

  ReassemblingState_t m_reassemblingState;

  Ptr<Packet> m_keepS0;

  /**

   * Expected Sequence Number

   */

  SequenceNumber10 m_expectedSeqNumber;

};

} // namespace ns3

#endif // LTE_RLC_AM_H