#define button 0
#define buzzer A0

// segments
#define a 6
#define b 7
#define c 8
#define d 9
#define e 10
#define f 12
#define g 11
#define p 13

// digits
#define d4 5
#define d3 4
#define d2 3
#define d1 2

unsigned long lastTimeUpdate = 0;
unsigned long lastDisplayRefresh = 0;

bool buttonWasPressed = false;
bool showVariant = true; // режим: true - варіант 19, false - секундомір
int variantNumber = 19;

int totalSeconds = 0;
int displayDigits[4] = {0,0,0,0};
int currentDisplayDigit = 1;

void setup() {
  pinMode(button, INPUT_PULLUP);

  pinMode(d1, OUTPUT); pinMode(d2, OUTPUT);
  pinMode(d3, OUTPUT); pinMode(d4, OUTPUT);

  pinMode(a, OUTPUT); pinMode(b, OUTPUT);
  pinMode(c, OUTPUT); pinMode(d, OUTPUT);
  pinMode(e, OUTPUT); pinMode(f, OUTPUT);
  pinMode(g, OUTPUT); pinMode(p, OUTPUT);

  clearAllSegments();
  turnOffAllDigits();

  lastTimeUpdate = millis();
}

void loop() {
  handleButton();
  runStopwatch();     // Пункт 2 завдання
  updateDisplay(showVariant ? variantNumber : totalSeconds); // Пункт 1 завдання
  refreshDisplay();
}

// 3. Реалізація перемикання режимів
void handleButton(){
  bool pressed = (digitalRead(button) == LOW);
  if(pressed && !buttonWasPressed){
    buttonWasPressed = true;
    showVariant = !showVariant;
    tone(buzzer, 1000, 80);
  }
  if(!pressed && buttonWasPressed){
    buttonWasPressed = false;
  }
}

// 2. Функція секундоміра
void runStopwatch(){
  unsigned long currentMillis = millis();
  while(currentMillis - lastTimeUpdate >= 1000){
    lastTimeUpdate += 1000;
    totalSeconds++;
    if(totalSeconds > 9999) totalSeconds = 0;
  }
}

// 1. Універсальна функція відображення будь-якого числа
void updateDisplay(int number){
  if(number > 9999) number = 9999;
  
  displayDigits[0] = number / 1000;
  displayDigits[1] = (number / 100) % 10;
  displayDigits[2] = (number / 10) % 10;
  displayDigits[3] = number % 10;
}

void refreshDisplay(){
  if(millis() - lastDisplayRefresh < 2) return;
  lastDisplayRefresh = millis();

  turnOffAllDigits();
  clearAllSegments();

  displayNumberOnDigit(displayDigits[currentDisplayDigit-1], currentDisplayDigit);

  currentDisplayDigit++;
  if(currentDisplayDigit > 4) currentDisplayDigit = 1;
}

void displayNumberOnDigit(int number, int digit){
  pickDigit(digit);
  pickNumber(number);
}

void turnOffAllDigits(){
  digitalWrite(d1, HIGH); digitalWrite(d2, HIGH);
  digitalWrite(d3, HIGH); digitalWrite(d4, HIGH);
}

void pickDigit(int x){
  switch(x){
    case 1: digitalWrite(d1, LOW); break;
    case 2: digitalWrite(d2, LOW); break;
    case 3: digitalWrite(d3, LOW); break;
    case 4: digitalWrite(d4, LOW); break;
  }
}

void pickNumber(int x){
  clearAllSegments();
  switch(x){
    case 0: zero(); break;
    case 1: one(); break;
    case 2: two(); break;
    case 3: three(); break;
    case 4: four(); break;
    case 5: five(); break;
    case 6: six(); break;
    case 7: seven(); break;
    case 8: eight(); break;
    case 9: nine(); break;
  }
}

void clearAllSegments(){
  digitalWrite(a, LOW); digitalWrite(b, LOW); digitalWrite(c, LOW);
  digitalWrite(d, LOW); digitalWrite(e, LOW); digitalWrite(f, LOW);
  digitalWrite(g, LOW); digitalWrite(p, LOW);
}

void zero()  { digitalWrite(a,HIGH); digitalWrite(b,HIGH); digitalWrite(c,HIGH); digitalWrite(d,HIGH); digitalWrite(e,HIGH); digitalWrite(f,HIGH); digitalWrite(g,LOW); }
void one()   { digitalWrite(a,LOW);  digitalWrite(b,HIGH); digitalWrite(c,HIGH); digitalWrite(d,LOW);  digitalWrite(e,LOW);  digitalWrite(f,LOW);  digitalWrite(g,LOW); }
void two()   { digitalWrite(a,HIGH); digitalWrite(b,HIGH); digitalWrite(c,LOW);  digitalWrite(d,HIGH); digitalWrite(e,HIGH); digitalWrite(f,LOW);  digitalWrite(g,HIGH); }
void three() { digitalWrite(a,HIGH); digitalWrite(b,HIGH); digitalWrite(c,HIGH); digitalWrite(d,HIGH); digitalWrite(e,LOW);  digitalWrite(f,LOW);  digitalWrite(g,HIGH); }
void four()  { digitalWrite(a,LOW);  digitalWrite(b,HIGH); digitalWrite(c,HIGH); digitalWrite(d,LOW);  digitalWrite(e,LOW);  digitalWrite(f,HIGH); digitalWrite(g,HIGH); }
void five()  { digitalWrite(a,HIGH); digitalWrite(b,LOW);  digitalWrite(c,HIGH); digitalWrite(d,HIGH); digitalWrite(e,LOW);  digitalWrite(f,HIGH); digitalWrite(g,HIGH); }
void six()   { digitalWrite(a,HIGH); digitalWrite(b,LOW);  digitalWrite(c,HIGH); digitalWrite(d,HIGH); digitalWrite(e,HIGH); digitalWrite(f,HIGH); digitalWrite(g,HIGH); }
void seven() { digitalWrite(a,HIGH); digitalWrite(b,HIGH); digitalWrite(c,HIGH); digitalWrite(d,LOW);  digitalWrite(e,LOW);  digitalWrite(f,LOW);  digitalWrite(g,LOW); }
void eight() { digitalWrite(a,HIGH); digitalWrite(b,HIGH); digitalWrite(c,HIGH); digitalWrite(d,HIGH); digitalWrite(e,HIGH); digitalWrite(f,HIGH); digitalWrite(g,HIGH); }
void nine()  { digitalWrite(a,HIGH); digitalWrite(b,HIGH); digitalWrite(c,HIGH); digitalWrite(d,LOW);  digitalWrite(e,LOW);  digitalWrite(f,HIGH); digitalWrite(g,HIGH); }