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

/*

 * Copyright (c) 2005,2006,2007 INRIA

 *

 * 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>

 */

#ifndef WIFI_REMOTE_STATION_MANAGER_H

#define WIFI_REMOTE_STATION_MANAGER_H

#include <vector>

#include <utility>

#include "ns3/mac48-address.h"

#include "ns3/packet.h"

#include "ns3/object.h"

#include "ns3/traced-value.h"

#include "wifi-mode.h"

namespace ns3 {

class WifiRemoteStation;

class NonUnicastWifiRemoteStation;

class WifiPhy;

/**

 * \brief hold a list of per-remote-station state.

 *

 * \sa ns3::WifiRemoteStation.

 */

class WifiRemoteStationManager : public Object

{

private:

  typedef std::vector<WifiMode> BasicModes;

public:

  typedef BasicModes::const_iterator BasicModesIterator;

  static TypeId GetTypeId (void);

  WifiRemoteStationManager ();

  virtual ~WifiRemoteStationManager ();

  virtual void SetupPhy (Ptr<WifiPhy> phy);

  uint32_t GetMaxSsrc (void) const;

  uint32_t GetMaxSlrc (void) const;

  uint32_t GetRtsCtsThreshold (void) const;

  uint32_t GetFragmentationThreshold (void) const;

  void SetMaxSsrc (uint32_t maxSsrc);

  void SetMaxSlrc (uint32_t maxSlrc);

  void SetRtsCtsThreshold (uint32_t threshold);

  void SetFragmentationThreshold (uint32_t threshold);

  // Invoked in a STA upon dis-association

  // or in an AP upon reboot

  void Reset (void);

  // Invoked in a STA upon association to store

  // the set of rates which belong to the 

  // BSSBasicRateSet of the associated AP

  // and which are supported locally.

  // Invoked in an AP to configure the BSSBasicRateSet

  void AddBasicMode (WifiMode mode);

  WifiMode GetDefaultMode (void) const;

  uint32_t GetNBasicModes (void) const;

  WifiMode GetBasicMode (uint32_t i) const;

  BasicModesIterator BeginBasicModes (void) const;

  BasicModesIterator EndBasicModes (void) const;

  bool IsLowLatency (void) const;

  WifiRemoteStation *Lookup (Mac48Address address);

  WifiRemoteStation *LookupNonUnicast (void);

protected:

  friend class WifiRemoteStation;

  virtual void DoDispose (void);

private:

  typedef std::vector <std::pair<Mac48Address, WifiRemoteStation *> > Stations;

  virtual class WifiRemoteStation *CreateStation (void) = 0;

  Stations m_stations;

  WifiMode m_defaultTxMode;

  NonUnicastWifiRemoteStation *m_nonUnicast;

  BasicModes m_basicModes;

  bool m_isLowLatency;

  uint32_t m_maxSsrc;

  uint32_t m_maxSlrc;

  uint32_t m_rtsCtsThreshold;

  uint32_t m_fragmentationThreshold;

};

} // namespace ns3

namespace ns3 {

/**

 * \brief hold per-remote-station state.

 *

 * The state in this class is used to keep track

 * of association status if we are in an infrastructure

 * network and to perform the selection of tx parameters

 * on a per-packet basis.

 */

class WifiRemoteStation {

public:

  static TypeId GetTypeId (void);

  WifiRemoteStation ();

  virtual ~WifiRemoteStation ();

  /**

   * Invoked in an AP upon disassociation of a

   * specific STA.

   */

  void Reset (void);

  /**

   * Invoked in a STA or AP to store the set of 

   * modes supported by a destination which is

   * also supported locally.

   * The set of supported modes includes

   * the BSSBasicRateSet.

   */

  void AddSupportedMode (WifiMode mode);

  bool IsBrandNew (void) const;

  bool IsAssociated (void) const;

  bool IsWaitAssocTxOk (void) const;

  void RecordWaitAssocTxOk (void);

  void RecordGotAssocTxOk (void);

  void RecordGotAssocTxFailed (void);

  void RecordDisassociated (void);

  /**

   * \param packet the packet to queue

   * \param fullPacketSize the size of the packet after its 802.11 MAC header has been added.

   *

   * This method is typically invoked just before queuing a packet for transmission.

   * It is a no-op unless the IsLowLatency attribute of the attached ns3::WifiRemoteStationManager

   * is set to false, in which case, the tx parameters of the packet are calculated and stored in

   * the packet as a tag. These tx parameters are later retrieved from GetDadaMode and GetRtsMode.

   */

  void PrepareForQueue (Ptr<const Packet> packet, uint32_t fullPacketSize);

  /**

   * \param packet the packet to send

   * \param fullPacketSize the size of the packet after its 802.11 MAC header has been added.

   * \returns the transmission mode to use to send this packet

   */

  WifiMode GetDataMode (Ptr<const Packet> packet, uint32_t fullPacketSize);

  /**

   * \param packet the packet to send

   * \returns the transmission mode to use to send the RTS prior to the

   *          transmission of the data packet itself.

   */

  WifiMode GetRtsMode (Ptr<const Packet> packet);

  /**

   * Should be invoked whenever the RtsTimeout associated to a transmission

   * attempt expires.

   */

  void ReportRtsFailed (void);

  /**

   * Should be invoked whenever the AckTimeout associated to a transmission

   * attempt expires.

   */

  void ReportDataFailed (void);

  /**

   * Should be invoked whenever we receive the Cts associated to an RTS 

   * we just sent.

   */

  void ReportRtsOk (double ctsSnr, WifiMode ctsMode, double rtsSnr);

  /**

   * Should be invoked whenever we receive the Ack associated to a data packet

   * we just sent.

   */

  void ReportDataOk (double ackSnr, WifiMode ackMode, double dataSnr);

  /**

   * Should be invoked after calling ReportRtsFailed if 

   * NeedRtsRetransmission returns false

   */

  void ReportFinalRtsFailed (void);

  /**

   * Should be invoked after calling ReportDataFailed if 

   * NeedDataRetransmission returns false

   */

  void ReportFinalDataFailed (void);

  /**

   * \param rxSnr the snr of the packet received

   * \param txMode the transmission mode used for the packet received.

   *

   * Should be invoked whenever a packet is successfully received.

   */

  void ReportRxOk (double rxSnr, WifiMode txMode);

  /**

   * \param packet the packet to send

   * \returns true if we want to use an RTS/CTS handshake for this

   *          packet before sending it, false otherwise.

   */

  virtual bool NeedRts (Ptr<const Packet> packet);

  /**

   * \param packet the packet to send

   * \returns true if we want to restart a failed RTS/CTS 

   *          handshake, false otherwise.

   */

  virtual bool NeedRtsRetransmission (Ptr<const Packet> packet);

  /**

   * \param packet the packet to send

   * \returns true if we want to resend a packet 

   *          after a failed transmission attempt, false otherwise.

   */

  virtual bool NeedDataRetransmission (Ptr<const Packet> packet);

  /**

   * \param packet the packet to send

   * \returns true if this packet should be fragmented, false otherwise.

   */

  virtual bool NeedFragmentation (Ptr<const Packet> packet);

  /**

   * \param packet the packet to send

   * \param fragmentNumber the fragment index of the next fragment to send (starts at zero).

   * \returns the size of the corresponding fragment.

   */

  virtual uint32_t GetFragmentSize (Ptr<const Packet> packet, uint32_t fragmentNumber);

  /**

   * \param packet the packet to send

   * \param fragmentNumber the fragment index of the next fragment to send (starts at zero).

   * \returns the offset within the original packet where this fragment starts.

   */

  virtual uint32_t GetFragmentOffset (Ptr<const Packet> packet, uint32_t fragmentNumber);

  /**

   * \param packet the packet to send

   * \param fragmentNumber the fragment index of the next fragment to send (starts at zero).

   * \returns true if this is the last fragment, false otherwise.

   */

  virtual bool IsLastFragment (Ptr<const Packet> packet, uint32_t fragmentNumber);

  /**

   * \param rtsMode the transmission mode used to send an RTS we just received

   * \returns the transmission mode to use for the CTS to complete the RTS/CTS

   *          handshake.

   */

  WifiMode GetCtsMode (WifiMode rtsMode);

  /**

   * \param dataMode the transmission mode used to send an ACK we just received

   * \returns the transmission mode to use for the ACK to complete the data/ACK

   *          handshake.

   */

  WifiMode GetAckMode (WifiMode dataMode);

private:

  typedef std::vector<WifiMode> SupportedModes;

  virtual Ptr<WifiRemoteStationManager> GetManager (void) const = 0;

  virtual WifiMode DoGetDataMode (uint32_t size) = 0;

  virtual WifiMode DoGetRtsMode (void) = 0;

  uint32_t GetNFragments (Ptr<const Packet> packet);

protected:

  virtual void DoReportRtsFailed (void) = 0;

  virtual void DoReportDataFailed (void) = 0;

  virtual void DoReportRtsOk (double ctsSnr, WifiMode ctsMode, double rtsSnr) = 0;

  virtual void DoReportDataOk (double ackSnr, WifiMode ackMode, double dataSnr) = 0;

  virtual void DoReportFinalRtsFailed (void) = 0;

  virtual void DoReportFinalDataFailed (void) = 0;

  virtual void DoReportRxOk (double rxSnr, WifiMode txMode) = 0;

  uint32_t GetNSupportedModes (void) const;

  WifiMode GetSupportedMode (uint32_t i) const;

private:

  bool IsIn (WifiMode mode) const;

  WifiMode GetControlAnswerMode (WifiMode reqMode);

  enum {

    BRAND_NEW,

    DISASSOC,

    WAIT_ASSOC_TX_OK,

    GOT_ASSOC_TX_OK

  } m_state;

  SupportedModes m_modes;

  TracedValue<uint32_t> m_ssrc;

  TracedValue<uint32_t> m_slrc;

};

} // namespace ns3 

#endif /* MAC_STATIONS_H */