#include <SPI.h>

#define BUTTON_PIN 2
#define STORAGE_PIN 8

volatile unsigned long delayTime = 500;
const unsigned long startDelayTime = 500;
const int step = 150;

class Button
{
public:
  Button(int pinB)
  {
    _lastButton = HIGH;
    _curButton = HIGH;
    _pinButton = pinB;
    pinMode(pinB, INPUT_PULLUP);
  }

  ~Button() = default;

  void process()
  {
    _curButton = debounce();
    if (_lastButton == HIGH && _curButton == LOW)
    {
      if(delayTime <= step)
      {
        delayTime = startDelayTime;
      }
      else
      {
        delayTime -= step;       
      }      
    }
    _lastButton = _curButton;
  }

private:
  int _lastButton;
  int _curButton;
  int _pinButton;

  int debounce ()
  {
    int current = digitalRead(_pinButton);
    if(_lastButton != current)
    {
      delay(5);
      current = digitalRead(_pinButton);
    }
    return current;
  }
};

volatile Button button(BUTTON_PIN);

void rotateLeft(uint16_t &bits)
{
uint16_t high_bit = bits & (1 << 15) ? 1 : 0;
bits = (bits << 1) | high_bit;
}

void proxyButton()
{
  button.process();
}

void setup() 
{
  //attachInterrupt(0, proxyButton, CHANGE);
  attachInterrupt(digitalPinToInterrupt(BUTTON_PIN), proxyButton, CHANGE);
  SPI.begin();
  pinMode(STORAGE_PIN, OUTPUT);
  digitalWrite(STORAGE_PIN, LOW);
  SPI.transfer(0);
  SPI.transfer(0);
  digitalWrite(STORAGE_PIN, HIGH);
  digitalWrite(STORAGE_PIN, LOW);
}

void loop() {  
  static uint16_t runningLight = 1;
  SPI.transfer(runningLight>>8);
  SPI.transfer(runningLight);
  digitalWrite(STORAGE_PIN, HIGH);
  digitalWrite(STORAGE_PIN, LOW);
  rotateLeft(runningLight);
  noInterrupts();
  unsigned long tmpTime = delayTime;
  interrupts();
  delay(tmpTime);
}