#ifndef PID_v1_h
#define PID_v1_h
#define LIBRARY_VERSION 1.1.1

// Constants used in some of the functions below
#define AUTOMATIC 1
#define MANUAL 0
#define DIRECT 0
#define REVERSE 1

class PID
{

public:



  // commonly used functions **************************************************************************
  PID(double *, double *, double *, // * constructor.  links the PID to the Input, Output, and
      double, double, double, int); //   Setpoint.  Initial tuning parameters are also set here

  void SetMode(int Mode); // * sets PID to either Manual (0) or Auto (non-0)

  bool Compute(); // * performs the PID calculation.  it should be
                  //   called every time loop() cycles. ON/OFF and
                  //   calculation frequency can be set using SetMode
                  //   SetSampleTime respectively

  void SetOutputLimits(double, double); // clamps the output to a specific range. 0-255 by default, but
                                        // it's likely the user will want to change this depending on
                                        // the application

  // available but not commonly used functions ********************************************************
  void SetTunings(double, double,   // * While most users will set the tunings once in the
                  double);          //   constructor, this function gives the user the option
                                    //   of changing tunings during runtime for Adaptive control
  void SetControllerDirection(int); // * Sets the Direction, or "Action" of the controller. DIRECT
                                    //   means the output will increase when error is positive. REVERSE
                                    //   means the opposite.  it's very unlikely that this will be needed
                                    //   once it is set in the constructor.
  void SetSampleTime(int);          // * sets the frequency, in Milliseconds, with which
                                    //   the PID calculation is performed.  default is 100

  // Display functions ****************************************************************
  double GetKp();     // These functions query the pid for interal values.
  double GetKi();     //  they were created mainly for the pid front-end,
  double GetKd();     // where it's important to know what is actually
  int GetMode();      //  inside the PID.
  int GetDirection(); //

private:
  void Initialize();

  double dispKp; // * we'll hold on to the tuning parameters in user-entered
  double dispKi; //   format for display purposes
  double dispKd; //

  double kp; // * (P)roportional Tuning Parameter
  double ki; // * (I)ntegral Tuning Parameter
  double kd; // * (D)erivative Tuning Parameter

  int controllerDirection;

  double *myInput;    // * Pointers to the Input, Output, and Setpoint variables
  double *myOutput;   //   This creates a hard link between the variables and the
  double *mySetpoint; //   PID, freeing the user from having to constantly tell us
                      //   what these values are.  with pointers we'll just know.

  unsigned long lastTime;
  double ITerm, lastInput;

  unsigned long SampleTime;
  double outMin, outMax;
  bool inAuto;
};
#endif