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

/*

 * Copyright (c) 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: Nicola Baldo <nbaldo@cttc.es>

 */

#ifndef EPC_UE_NAS_H

#define EPC_UE_NAS_H

#include <ns3/object.h>

#include <ns3/lte-as-sap.h>

#include <ns3/epc-tft-classifier.h>

namespace ns3 {

class EpcHelper;

class EpcUeNas : public Object

{

  friend class MemberLteAsSapUser<EpcUeNas>;

public:

  /** 

   * Constructor

   */

  EpcUeNas ();

  /** 

   * Destructor

   */

  virtual ~EpcUeNas ();

  // inherited from Object

  virtual void DoDispose (void);

  static TypeId GetTypeId (void);

  /** 

   * 

   * \param dev the UE NetDevice

   */

  void SetDevice (Ptr<NetDevice> dev);

  /** 

   * 

   * 

   * \param imsi the unique UE identifier

   */

  void SetImsi (uint64_t imsi);

  /**

   *

   * \param csgId Closed Subscriber Group identity

   */

  void SetCsgId (uint32_t csgId);

  /**

   *

   * \return csgId Closed Subscriber Group identity

   */

  uint32_t GetCsgId () const;

  /**

   * Set the AS SAP provider to interact with the NAS entity

   *

   * \param s the AS SAP provider

   */

  void SetAsSapProvider (LteAsSapProvider* s);

  /**

   *

   *

   * \return the AS SAP user exported by this RRC

   */

  LteAsSapUser* GetAsSapUser ();

  /**

   * set the callback used to forward data packets up the stack

   *

   * \param cb the callback

   */

  void SetForwardUpCallback (Callback <void, Ptr<Packet> > cb);

  /**

   * \brief Causes NAS to tell AS to find a suitable cell and camp to it.

   *

   * \param dlEarfcn the DL frequency of the eNB

   */

  void StartCellSelection (uint16_t dlEarfcn);

  /**

   * \brief Causes NAS to tell AS to go to ACTIVE state.

   * 

   * The end result is equivalent with EMM Registered + ECM Connected states.

   */

  void Connect ();

  /**

   * \brief Causes NAS to tell AS to camp to a specific cell and go to ACTIVE

   *        state.

   * \param cellId the id of the eNB to camp on

   * \param dlEarfcn the DL frequency of the eNB

   *

   * The end result is equivalent with EMM Registered + ECM Connected states.

   * Since RRC Idle Mode cell selection is not supported yet, we force the UE

   * RRC to be camped on a specific eNB.

   */

  void Connect (uint16_t cellId, uint16_t dlEarfcn);

  /** 

   * instruct the NAS to disconnect

   * 

   */

  void Disconnect ();

  /** 

   * Activate an EPS bearer

   * 

   * \param bearer the characteristics of the bearer to be created

   * \param tft the TFT identifying the traffic that will go on this bearer

   */

  void ActivateEpsBearer (EpsBearer bearer, Ptr<EpcTft> tft);

  /** 

   * Enqueue an IP packet on the proper bearer for uplink transmission

   * 

   * \param p the packet

   * 

   * \return true if successful, false if an error occurred

   */

  bool Send (Ptr<Packet> p);

  /**

   * Definition of NAS states as per "LTE - From theory to practice",

   * Section 3.2.3.2 "Connection Establishment and Release"

   * 

   */

  enum State 

  {

    OFF = 0,

    ATTACHING,

    IDLE_REGISTERED,

    CONNECTING_TO_EPC,

    ACTIVE,

    NUM_STATES

  };

  /**

   * \return The current state

   */

  State GetState () const;

private:

  // LTE AS SAP methods

  void DoNotifyConnectionSuccessful ();

  void DoNotifyConnectionFailed ();

  void DoNotifyConnectionReleased ();

  void DoRecvData (Ptr<Packet> packet);

  // internal methods

  void DoActivateEpsBearer (EpsBearer bearer, Ptr<EpcTft> tft);

  void SwitchToState (State s);

  State m_state;

  TracedCallback<State, State> m_stateTransitionCallback;

  Ptr<NetDevice> m_device;

  uint64_t m_imsi;

  uint32_t m_csgId;

  LteAsSapProvider* m_asSapProvider;

  LteAsSapUser* m_asSapUser;

  uint8_t m_bidCounter;

  EpcTftClassifier m_tftClassifier;

  Callback <void, Ptr<Packet> > m_forwardUpCallback;

  struct BearerToBeActivated

  {

    EpsBearer bearer;

    Ptr<EpcTft> tft;

  };

  std::list<BearerToBeActivated> m_bearersToBeActivatedList;

};

} // namespace ns3

#endif // EPC_UE_NAS_H