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

/*

 * Copyright (c) 2005,2006 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_PHY_H

#define WIFI_PHY_H

#include <stdint.h>

#include "ns3/callback.h"

#include "ns3/packet.h"

#include "ns3/object.h"

#include "ns3/nstime.h"

#include "ns3/ptr.h"

#include "wifi-mode.h"

#include "wifi-preamble.h"

#include "wifi-phy-standard.h"

namespace ns3 {

class WifiChannel;

/**

 * \brief receive notifications about phy events.

 */

class WifiPhyListener {

public:

  virtual ~WifiPhyListener ();

  /**

   * \param duration the expected duration of the packet reception.

   *

   * we have received the first bit of a packet. We decided

   * that we could synchronize on this packet. It does not mean

   * we will be able to successfully receive completely the

   * whole packet. It means we will report a BUSY status.

   * NotifyRxEndOk or NotifyRxEndError will be invoked later 

   * to report whether or not the packet was successfully received.

   */

  virtual void NotifyRxStart (Time duration) = 0;

  /**

   * we have received the last bit of a packet for which

   * NotifyRxStart was invoked first and, the packet has

   * been successfully received.

   */

  virtual void NotifyRxEndOk (void) = 0;  

  /**

   * we have received the last bit of a packet for which

   * NotifyRxStart was invoked first and, the packet has

   * _not_ been successfully received.

   */

  virtual void NotifyRxEndError (void) = 0;

  /**

   * \param duration the expected transmission duration.

   *

   * We are about to send the first bit of the packet.

   */

  virtual void NotifyTxStart (Time duration) = 0;

  /**

   * \param duration the expected busy duration.

   *

   * We are going to be cca-busy for a while.

   */

  virtual void NotifyCcaBusyStart (Time duration) = 0;

};

/**

 * \brief 802.11 PHY layer model

 *

 */

class WifiPhy : public Object

{

public:

  /**

   * The state of the PHY layer.

   */

  enum State {

    /**

     * The PHY layer is synchronized upon a packet.

     */

    SYNC,

    /**

     * The PHY layer is sending a packet.

     */

    TX,

    /**

     * The PHY layer has sense the medium busy through

     * the CCA mechanism

     */

    CCA_BUSY,

    /**

     * The PHY layer is IDLE.

     */

    IDLE

  };

  /**

   * arg1: packet received successfully

   * arg2: snr of packet

   * arg3: mode of packet

   * arg4: type of preamble used for packet.

   */

  typedef Callback<void,Ptr<Packet>, double, WifiMode, enum WifiPreamble> SyncOkCallback;

  /**

   * arg1: packet received unsuccessfully

   * arg2: snr of packet

   */

  static TypeId GetTypeId (void);

  WifiPhy ();

  virtual ~WifiPhy ();

  virtual double GetTxPowerStart (void) const = 0;

  virtual double GetTxPowerEnd (void) const = 0;

  /**

   * \returns the number of tx power levels available for this PHY.

   */

  virtual uint32_t GetNTxPower (void) const = 0;

  /**

   * \param callback the callback to invoke

   *        upon successful packet reception.

   */

  virtual void SetReceiveOkCallback (SyncOkCallback callback) = 0;

  /**

   * \param callback the callback to invoke

   *        upon erronous packet reception.

   */

  virtual void SetReceiveErrorCallback (SyncErrorCallback callback) = 0;

  /**

   * \param packet the packet to send

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

   * \param preamble the type of preamble to use to send this packet.

   * \param txPowerLevel a power level to use to send this packet. The real

   *        transmission power is calculated as txPowerMin + txPowerLevel * (txPowerMax - txPowerMin) / nTxLevels

   */

  virtual void SendPacket (Ptr<const Packet> packet, WifiMode mode, enum WifiPreamble preamble, uint8_t txPowerLevel) = 0;

  /**

   * \param listener the new listener

   *

   * Add the input listener to the list of objects to be notified of

   * PHY-level events.

   */

  virtual void RegisterListener (WifiPhyListener *listener) = 0;

  /**

   * \returns true of the current state of the PHY layer is WifiPhy::CCA_BUSY, false otherwise.

   */

  virtual bool IsStateCcaBusy (void) = 0;

  /**

   * \returns true of the current state of the PHY layer is WifiPhy::IDLE, false otherwise.

   */

  virtual bool IsStateIdle (void) = 0;

  /**

   * \returns true of the current state of the PHY layer is not WifiPhy::IDLE, false otherwise.

   */

  virtual bool IsStateBusy (void) = 0;

  /**

   * \returns true of the current state of the PHY layer is WifiPhy::SYNC, false otherwise.

   */

  virtual bool IsStateSync (void) = 0;

  /**

   * \returns true of the current state of the PHY layer is WifiPhy::TX, false otherwise.

   */

  virtual bool IsStateTx (void) = 0;

  /**

   * \returns the amount of time since the current state has started.

   */

  virtual Time GetStateDuration (void) = 0;

  /**

   * \returns the predicted delay until this PHY can become WifiPhy::IDLE.

   *

   * The PHY will never become WifiPhy::IDLE _before_ the delay returned by

   * this method but it could become really idle later.

   */

  virtual Time GetDelayUntilIdle (void) = 0;

  virtual Time GetLastRxStartTime (void) const = 0;

  /**

   * \param size the number of bytes in the packet to send

   * \param payloadMode the transmission mode to use for this packet

   * \param preamble the type of preamble to use for this packet.

   * \returns the total amount of time this PHY will stay busy for

   *          the transmission of these bytes.

   */

  virtual Time CalculateTxDuration (uint32_t size, WifiMode payloadMode, enum WifiPreamble preamble) const = 0;

  /**

   * \returns the number of transmission modes supported by this PHY.

   */

  virtual uint32_t GetNModes (void) const = 0;

  /**

   * \param mode index in array of supported modes

   * \returns the mode whose index is specified.

   */

  virtual WifiMode GetMode (uint32_t mode) const = 0;

  /* return snr: W/W */

  /**

   * \param txMode the transmission mode

   * \param ber the probability of bit error rate

   * \returns the minimum snr which is required to achieve

   *          the requested ber for the specified transmission mode.

   */

  virtual double CalculateSnr (WifiMode txMode, double ber) const = 0;

  virtual Ptr<WifiChannel> GetChannel (void) const = 0;

  static WifiMode g_6mba;

  static WifiMode g_9mba;

  static WifiMode g_12mba;

  static WifiMode g_18mba;

  static WifiMode g_24mba;

  static WifiMode g_36mba;

  static WifiMode g_48mba;

  static WifiMode g_54mba;

};

} // namespace ns3

#endif /* WIFI_PHY_H */