#include "Eventfun.h"

////////////////////////////////////
// definition for DigitalPin class
///////////////////////////////////

// define a class representing digital pin
template<typename T>
class DigitalPin {
protected:
  int _pin; // pin number
  bool _value; // last value read from the pin
  unsigned long _msDebounce;
  unsigned long _ms;
  bool _debouncing;
public:
  // declare event
  typedef EventDelegate<T, bool> ChangeEvent;
  ChangeEvent OnChange;

public:
  // initialize DigitalPin object
  DigitalPin(int pin, int pin_mode, int msDebounce = 0) 
    : _pin(pin), _msDebounce(msDebounce), _debouncing(false) {
    pinMode(_pin, pin_mode);
    if (pin_mode != OUTPUT) {
      _value = digitalRead(_pin);
    }
  }

  // read the pin value and only trigger the event if there is a change
  void Update() {    
    auto value = digitalRead(_pin);    
    if (value != _value) {
      if (_debouncing && millis() - _ms > _msDebounce)
      {
        _debouncing = false;
        _value = value; // update to the new value
        OnChange((T*)this, _value); // trigger event
      }
      else if (!_debouncing) {
        _ms = millis();
        _debouncing = true;
      }
    }      
  }

  // accessor for _pin
  int Pin() {
    return _pin;
  }
  
  // for convenience overload () operator to set value
  operator()(bool value) {
    _value = value;
    digitalWrite(_pin, value);
  }

  // for convenience overload bool operator to return value
  operator bool() {
    return _value;
  }
};


// now that we have a class representing a digital pin
// we can create classes that use digital pin

// a button
class Button: public DigitalPin<Button> {
public:
  Button(int pin) : DigitalPin(pin, INPUT_PULLUP, 100) {
  }
};

// a LED
class Led: public DigitalPin<Led> {
public:
  Led(int pin, Button& button) : DigitalPin(pin, OUTPUT) {
    button.OnChange = Button::ChangeEvent(this, &Led::onButtonClick);
  }

  void onButtonClick(Button* sender, bool value) {
    Serial.println("hello");
    operator()(!value);
  }
};

// it may look like too much for a simple project but when you have many 
// interconnected components that need to react to changes and  interact with one another
// then using classes with events may simplify your program:

//////////////////
// main program
/////////////////

Button redButton(12);
Button greenButton(2);

Led redLed(redButton.Pin() + 1, redButton);
Led greenLed(greenButton.Pin() + 1, greenButton);

void setup() {
  Serial.begin(115200);;
}

void loop() {
  redButton.Update();
  greenButton.Update();
}