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

/*

 * Copyright (c) 2010 Network Security Lab, University of Washington, Seattle.

 *

 * 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: Sidharth Nabar <snabar@uw.edu>, He Wu <mdzz@u.washington.edu>

 */

#ifndef WIFI_RADIO_ENERGY_MODEL_H

#define WIFI_RADIO_ENERGY_MODEL_H

#include "ns3/device-energy-model.h"

#include "ns3/nstime.h"

#include "ns3/event-id.h"

#include "ns3/traced-value.h"

#include "ns3/wifi-phy.h"

namespace ns3 {

/**

 * A WifiPhy listener class for notifying the WifiRadioEnergyModel of Wifi radio

 * state change.

 */

class WifiRadioEnergyModelPhyListener : public WifiPhyListener

{

public:

  WifiRadioEnergyModelPhyListener ();

  virtual ~WifiRadioEnergyModelPhyListener ();

  /**

   * \brief Sets the change state callback. Used by helper class.

   *

   * \param callback Change state callback.

   */

  void SetChangeStateCallback (DeviceEnergyModel::ChangeStateCallback callback);

  /**

   * \brief Switches the WifiRadioEnergyModel to RX state.

   *

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

   *

   * Defined in ns3::WifiPhyListener

   */

  virtual void NotifyRxStart (Time duration);

  /**

   * \brief Switches the WifiRadioEnergyModel back to IDLE state.

   *

   * Defined in ns3::WifiPhyListener

   *

   * Note that for the WifiRadioEnergyModel, the behavior of the function is the

   * same as NotifyRxEndError.

   */

  virtual void NotifyRxEndOk (void);

  /**

   * \brief Switches the WifiRadioEnergyModel back to IDLE state.

   *

   * Defined in ns3::WifiPhyListener

   *

   * Note that for the WifiRadioEnergyModel, the behavior of the function is the

   * same as NotifyRxEndOk.

   */

  virtual void NotifyRxEndError (void);

  /**

   * \brief Switches the WifiRadioEnergyModel to TX state and switches back to

   * IDLE after TX duration.

   *

   * \param duration the expected transmission duration.

   *

   * Defined in ns3::WifiPhyListener

   */

  virtual void NotifyTxStart (Time duration);

  /**

   * \param duration the expected busy duration.

   *

   * Defined in ns3::WifiPhyListener

   */

  virtual void NotifyMaybeCcaBusyStart (Time duration);

  /**

   * \param duration the expected channel switching duration.

   *

   * Defined in ns3::WifiPhyListener

   */

  virtual void NotifySwitchingStart (Time duration);

private:

  /**

   * A helper function that makes scheduling m_changeStateCallback possible.

   */

  void SwitchToIdle (void);

private:

  /**

   * Change state callback used to notify the WifiRadioEnergyModel of a state

   * change.

   */

  DeviceEnergyModel::ChangeStateCallback m_changeStateCallback;

  EventId m_switchToIdleEvent;

};

// -------------------------------------------------------------------------- //

/**

 * \brief A WiFi radio energy model.

 * 

 * 4 states are defined for the radio: TX, RX, IDLE, SLEEP. Default state is

 * IDLE.

 * The different types of transactions that are defined are: 

 *  1. Tx: State goes from IDLE to TX, radio is in TX state for TX_duration,

 *     then state goes from TX to IDLE.

 *  2. Rx: State goes from IDLE to RX, radio is in RX state for RX_duration,

 *     then state goes from RX to IDLE.

 *  3. Go_to_Sleep: State goes from IDLE to SLEEP.

 *  4. End_of_Sleep: State goes from SLEEP to IDLE.

 * The class keeps track of what state the radio is currently in.

 *

 * Energy calculation: For each transaction, this model notifies EnergySource

 * object. The EnergySource object will query this model for the total current.

 * Then the EnergySource object uses the total current to calculate energy.

 *

 * Default values for power consumption are based on CC2420 radio chip, with

 * supply voltage as 2.5V and currents as 17.4 mA (TX), 18.8 mA (RX), 20 uA

 * (sleep) and 426 uA (idle).

 */

class WifiRadioEnergyModel : public DeviceEnergyModel

{

public:

  /**

   * Callback type for energy depletion handling.

   */

  typedef Callback<void> WifiRadioEnergyDepletionCallback;

public:

  static TypeId GetTypeId (void);

  WifiRadioEnergyModel ();

  virtual ~WifiRadioEnergyModel ();

  /**

   * \brief Sets pointer to EnergySouce installed on node.

   *

   * \param source Pointer to EnergySource installed on node.

   *

   * Implements DeviceEnergyModel::SetEnergySource.

   */

  virtual void SetEnergySource (Ptr<EnergySource> source);

  /**

   * \returns Total energy consumption of the wifi device.

   *

   * Implements DeviceEnergyModel::GetTotalEnergyConsumption.

   */

  virtual double GetTotalEnergyConsumption (void) const;

  // Setter & getters for state power consumption.

  double GetIdleCurrentA (void) const;

  void SetIdleCurrentA (double idleCurrentA);

  double GetCcaBusyCurrentA (void) const;

  void SetCcaBusyCurrentA (double ccaBusyCurrentA);

  double GetTxCurrentA (void) const;

  void SetTxCurrentA (double txCurrentA);

  double GetRxCurrentA (void) const;

  void SetRxCurrentA (double rxCurrentA);

  double GetSwitchingCurrentA (void) const;

  void SetSwitchingCurrentA (double switchingCurrentA);

  /**

   * \returns Current state.

   */

  WifiPhy::State GetCurrentState (void) const;

  /**

   * \param callback Callback function.

   *

   * Sets callback for energy depletion handling.

   */

  void SetEnergyDepletionCallback (WifiRadioEnergyDepletionCallback callback);

  /**

   * \brief Changes state of the WifiRadioEnergyMode.

   *

   * \param newState New state the wifi radio is in.

   *

   * Implements DeviceEnergyModel::ChangeState.

   */

  virtual void ChangeState (int newState);

  /**

   * \brief Handles energy depletion.

   *

   * Implements DeviceEnergyModel::HandleEnergyDepletion

   */

  virtual void HandleEnergyDepletion (void);

  /**

   * \returns Pointer to the PHY listener.

   */

  WifiRadioEnergyModelPhyListener * GetPhyListener (void);

private:

  void DoDispose (void);

  /**

   * \returns Current draw of device, at current state.

   *

   * Implements DeviceEnergyModel::GetCurrentA.

   */

  virtual double DoGetCurrentA (void) const;

  /**

   * \param currentState New state the radio device is currently in.

   *

   * Sets current state. This function is private so that only the energy model

   * can change its own state.

   */

  void SetWifiRadioState (const WifiPhy::State state);

private:

  Ptr<EnergySource> m_source;

  // Member variables for current draw in different radio modes.

  double m_txCurrentA;

  double m_rxCurrentA;

  double m_idleCurrentA;

  double m_ccaBusyCurrentA;

  double m_switchingCurrentA;

  // This variable keeps track of the total energy consumed by this model.

  TracedValue<double> m_totalEnergyConsumption;

  // State variables.

  WifiPhy::State m_currentState;  // current state the radio is in

  Time m_lastUpdateTime;          // time stamp of previous energy update

  // Energy depletion callback

  WifiRadioEnergyDepletionCallback m_energyDepletionCallback;

  // WifiPhy listener

  WifiRadioEnergyModelPhyListener *m_listener;

};

} // namespace ns3

#endif /* WIFI_RADIO_ENERGY_MODEL_H */