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// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
#pragma once
#include <string>
#include <units/time.h>
#include <wpi/mutex.h>
#include "frc/Timer.h"
namespace frc {
/**
* The Motor Safety feature acts as a watchdog timer for an individual motor. It
* operates by maintaining a timer that tracks how long it has been since the
* feed() method has been called for that actuator. Code in the Driver Station
* class initiates a comparison of these timers to the timeout values for any
* actuator with safety enabled every 5 received packets (100ms nominal).
*
* The subclass should call Feed() whenever the motor value is updated.
*/
class MotorSafety {
public:
MotorSafety();
virtual ~MotorSafety();
MotorSafety(MotorSafety&& rhs);
MotorSafety& operator=(MotorSafety&& rhs);
/**
* Feed the motor safety object.
*
* Resets the timer on this object that is used to do the timeouts.
*/
void Feed();
/**
* Set the expiration time for the corresponding motor safety object.
*
* @param expirationTime The timeout value.
*/
void SetExpiration(units::second_t expirationTime);
/**
* Retrieve the timeout value for the corresponding motor safety object.
*
* @return the timeout value.
*/
units::second_t GetExpiration() const;
/**
* Determine if the motor is still operating or has timed out.
*
* @return true if the motor is still operating normally and hasn't timed out.
*/
bool IsAlive() const;
/**
* Enable/disable motor safety for this device.
*
* Turn on and off the motor safety option for this PWM object.
*
* @param enabled True if motor safety is enforced for this object.
*/
void SetSafetyEnabled(bool enabled);
/**
* Return the state of the motor safety enabled flag.
*
* Return if the motor safety is currently enabled for this device.
*
* @return True if motor safety is enforced for this device.
*/
bool IsSafetyEnabled() const;
/**
* Check if this motor has exceeded its timeout.
*
* This method is called periodically to determine if this motor has exceeded
* its timeout value. If it has, the stop method is called, and the motor is
* shut down until its value is updated again.
*/
void Check();
/**
* Check the motors to see if any have timed out.
*
* This static method is called periodically to poll all the motors and stop
* any that have timed out.
*/
static void CheckMotors();
/**
* Called to stop the motor when the timeout expires.
*/
virtual void StopMotor() = 0;
/**
* Returns a description to print when an error occurs.
*
* @return Description to print when an error occurs.
*/
virtual std::string GetDescription() const = 0;
private:
static constexpr auto kDefaultSafetyExpiration = 100_ms;
// The expiration time for this object
units::second_t m_expiration = kDefaultSafetyExpiration;
// True if motor safety is enabled for this motor
bool m_enabled = false;
// The FPGA clock value when the motor has expired
units::second_t m_stopTime = Timer::GetFPGATimestamp();
mutable wpi::mutex m_thisMutex;
};
} // namespace frc