#include <Arduino.h>

#define START_PIN      39
#define STOP_PIN       36
#define CLEAR_PIN      34
#define COUNT_UP_PIN   35
#define COUNT_DOWN_PIN 32

bool run = 0;
bool up = 0;
bool down = 0;
bool clear = 0;
int count = 0;

int segmentPins[] = {23, 22, 21, 19, 18, 5, 17};
int digitPins[] = {4, 16};

byte segments[] = {
  B0111111, // 0
  B0000110, // 1
  B1011011, // 2
  B1001111, // 3
  B1100110, // 4
  B1101101, // 5
  B1111101, // 6
  B0000111, // 7
  B1111111, // 8
  B1101111, // 9
  B0000000  // clear
};

void setup() {
  pinMode(START_PIN, INPUT);
  pinMode(STOP_PIN, INPUT);
  pinMode(CLEAR_PIN, INPUT);
  pinMode(COUNT_UP_PIN, INPUT);
  pinMode(COUNT_DOWN_PIN, INPUT);

  for (int i = 0; i < 7; i++) {
    pinMode(segmentPins[i], OUTPUT);
  }

  for (int i = 0; i < 2; i++) {
    pinMode(digitPins[i], OUTPUT);
  }

  secmentDisplay(count);
}

void loop()
{
  getButton();
  if (run)
  {
    // count = --count > 0 ? count : run = 0;
    count = ++count == 99 ? run = 0 : count;
  }
  else
  {
    if (up)
    {
      count = ++count > 99 ? 0 : count;
      up = 0;
    }
    if(down)
    {
      count = --count > 0 ? count : 99;
      down = 0;
    }
  }

  if (clear)
  {
    count = 0;
    clear = 0;
  }
  secmentDisplay(count);
}

void displayDigit(int digit) {
  for (int i = 0; i < 7; i++) {
    digitalWrite(segmentPins[i], bitRead(segments[digit], i));
  }
  delay(30);
}

void secmentDisplay(int num)
{
  digitalWrite(digitPins[0], HIGH);
  digitalWrite(digitPins[1], LOW);
  displayDigit(num / 10);
  displayDigit(10);
  delay(5);
  digitalWrite(digitPins[0], LOW);
  digitalWrite(digitPins[1], HIGH);
  displayDigit(num % 10);
  displayDigit(10);
  delay(5);
}

void getButton()
{
  if (!digitalRead((START_PIN)))
    run = 1;
  if (!digitalRead((STOP_PIN)))
    run = 0;
  if (!digitalRead((CLEAR_PIN)))
    clear = 1;
  if (!digitalRead((COUNT_UP_PIN)))
    up = 1;
  if (!digitalRead((COUNT_DOWN_PIN)))
    down = 1;
}