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

/* 

 * Copyright (c) 2009 IITP RAS

 * 

 * 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

 * 

 * Authors: Kirill Andreev <andreev@iitp.ru>

 *          Aleksey Kovalenko <kovalenko@iitp.ru>

 */

#ifndef PEERLLINK_H_

#define PEERLLINK_H_

#include "ns3/nstime.h"

#include "ns3/callback.h"

#include "ns3/mac48-address.h"

#include "ie-dot11s-beacon-timing.h"

#include "ie-dot11s-peer-management.h"

#include "ie-dot11s-configuration.h"

namespace ns3 {

namespace dot11s {

/**

 * \ingroup dot11s

 * 

 * \brief Peer link model for 802.11s Peer Management protocol 

 */

class PeerLink : public Object

{

public:

  friend class PeerManagerProtocol;

  /// Support object system

  static TypeId GetTypeId();

  /// C-tor create empty link

  PeerLink ();

  /// Process beacon received from peer

  void SetBeaconInformation (Time lastBeacon, Time BeaconInterval);

  /**

   * \brief Method used to detecet peer link changes

   * 

   * \param bool if true - opened new link, if false - link closed

   */

  void  SetLinkStatusCallback (Callback<void, uint32_t, Mac48Address, bool> cb);

  /**

   * \name Peer link geeters/setters

   * \{

   */

  void  SetPeerAddress (Mac48Address macaddr);

  void  SetInterface (uint32_t interface);

  void  SetLocalLinkId (uint16_t id);

  void  SetPeerLinkId (uint16_t id);

  void  SetLocalAid (uint16_t aid);

  void  SetPeerAid (uint16_t aid);

  void  SetBeaconTimingElement (IeBeaconTiming beaconTiming);

  void  SetPeerLinkDescriptorElement (IePeerManagement peerLinkElement);

  Mac48Address GetPeerAddress () const;

  uint16_t GetLocalAid () const;

  Time  GetLastBeacon () const;

  Time  GetBeaconInterval () const;

  IeBeaconTiming GetBeaconTimingElement ()const;

  IePeerManagement GetPeerLinkDescriptorElement ()const;

  void  ClearTimingElement ();

  //\}

  /**

   * \name MLME

   * \{

   */

  /// MLME-CancelPeerLink.request

  void MLMECancelPeerLink (dot11sReasonCode reason);

  /// MLME-PassivePeerLinkOpen.request

  void MLMEPassivePeerLinkOpen ();

  /// MLME-ActivePeerLinkOpen.request

  void MLMEActivePeerLinkOpen ();

  /// MLME-PeeringRequestReject

  void MLMEPeeringRequestReject ();

  /// Callback type for MLME-SignalPeerLinkStatus event

  typedef Callback<void, uint32_t, Mac48Address, bool> SignalStatusCallback; 

  /// Set callback

  void MLMESetSignalStatusCallback (SignalStatusCallback);

  //\}

private:

  /**

   * \name Link response to received management frames

   * 

   * \attention In all this methods {local/peer}LinkID correspond to _peer_ station, as written in

   * received frame, e.g. I am peerLinkID and peer link is localLinkID .

   * 

   * TODO is that clear?

   * 

   * \{

   */

  /// Close link

  void Close (uint16_t localLinkID, uint16_t peerLinkID, dot11sReasonCode reason);

  /// Accept open link

  void OpenAccept (uint16_t localLinkId, IeConfiguration conf);

  /// Reject open link 

  void OpenReject (uint16_t localLinkId, IeConfiguration conf, dot11sReasonCode reason);

  /// Confirm accept

  void ConfirmAccept (

    uint16_t localLinkId,

    uint16_t peerLinkId,

    uint16_t peerAid,

    IeConfiguration conf

  );

  /// Confirm reject

  void  ConfirmReject (

    uint16_t localLinkId,

    uint16_t peerLinkId,

    IeConfiguration  conf,

    dot11sReasonCode reason

  );

  //\}

  /// True if link is established

  bool  LinkIsEstab () const;

  /// True if link is idle. Link can be deleted in this state 

  bool  LinkIsIdle () const;

  /**

   * Set pointer to MAC-plugin, which is responsible for sending peer

   * link management frames

   */

  void SetMacPlugin(Ptr<PeerManagerMacPlugin> plugin);

private:

  /// Peer link states, see 802.11s draft 11B.3.3.1

  enum  PeerState {

    IDLE,       

    LISTEN,

    OPN_SNT,

    CNF_RCVD,

    OPN_RCVD,

    ESTAB,

    HOLDING,

  };

  /// Peer link events, see 802.11s draft 11B.3.3.2

  enum  PeerEvent

  {

    CNCL,       ///< MLME-CancelPeerLink

    PASOPN,     ///< MLME-PassivePeerLinkOpen

    ACTOPN,     ///< MLME-ActivePeerLinkOpen

    CLS_ACPT,   ///< PeerLinkClose_Accept

    OPN_ACPT,   ///< PeerLinkOpen_Accept

    OPN_RJCT,   ///< PeerLinkOpen_Reject

    REQ_RJCT,   ///< PeerLinkOpenReject by internal reason

    CNF_ACPT,   ///< PeerLinkConfirm_Accept

    CNF_RJCT,   ///< PeerLinkConfirm_Reject

    TOR1,       ///< Timeout of retry timer

    TOR2,       ///< also timeout of retry timer

    TOC,        ///< Timeout of confirm timer

    TOH,        ///< Timeout of holding (gracefull closing) timer

  };

private:

  /// State transition

  void StateMachine (PeerEvent event, dot11sReasonCode = REASON11S_RESERVED);

  /** 

   * \name Event handlers

   * \{ 

   */

  void ClearRetryTimer ();

  void ClearConfirmTimer ();

  void ClearHoldingTimer ();

  void SetHoldingTimer ();

  void SetRetryTimer ();

  void SetConfirmTimer ();

  //\}

  /** 

   * \name Work with management frames

   * \{

   */

  void SendPeerLinkClose (dot11sReasonCode reasoncode);

  void SendPeerLinkOpen ();

  void SendPeerLinkConfirm ();

  //\}

  /** 

   * \name Timeout handlers 

   * \{

   */

  void HoldingTimeout ();

  void RetryTimeout ();

  void ConfirmTimeout ();

  //\}

private:

  ///The number of interface I am associated with

  uint32_t m_interface;

  /// pointer to mac plugin, which is responsible for peer management

  Ptr<PeerManagerMacPlugin> m_macPlugin;

  /// Peer address

  Mac48Address m_peerAddress;

  /// My ID of this link

  uint16_t m_localLinkId;

  /// Peer ID of this link

  uint16_t m_peerLinkId;

  /// My association ID

  uint16_t m_assocId;

  /// Assoc Id assigned to me by peer

  uint16_t m_peerAssocId;

  /// When last beacon was sent (TODO or received?)

  Time  m_lastBeacon;

  /// Current beacon interval on corresponding interface

  Time  m_beaconInterval;

  /// Current state

  PeerState m_state;

  /// Mesh interface configuration

  IeConfiguration m_configuration;

  // State is a bitfield as defined as follows:

  // This are states for a given

  IeBeaconTiming m_beaconTiming;

  /**

   * \name Timers & counters used for internal state transitions

   * \{

   */

  Time     m_retryTimeout;

  EventId  m_retryTimer;

  Time     m_holdingTimeout;

  EventId  m_holdingTimer;

  Time     m_confirmTimeout;

  EventId  m_confirmTimer;

  uint16_t m_maxRetries;

  uint16_t m_retryCounter;

  EventId  m_beaconLossTimer;

  uint16_t  m_maxBeaconLoss;

  //\}

  /// ?

  void BeaconLoss ();

  /// How to report my status change

  SignalStatusCallback m_linkStatusCallback;

};

} // namespace dot11s

} //namespace ns3

#endif /* PEERLLINK_H_ */