#define DATA 2
#define LATCH 3
#define CLOCK 4
#define D1 5
#define D2 6
#define D3 7
#define D4 8
#define BPLUS 9
#define BMINUS 10

#define MIN 0;
#define MAX 999;

byte digits[] {
  B11111100, // 0
  B01100000, // 1
  B11011010, // 2
  B11110010, // 3
  B01100110, // 4
  B10110110, // 5
  B10111110, // 6
  B11100000, // 7
  B11111110, // 8
  B11110110, // 9
};

int display = 1;
int num = 0;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(DATA, OUTPUT);
  pinMode(LATCH, OUTPUT);
  pinMode(CLOCK, OUTPUT);
  pinMode(D1, OUTPUT);
  pinMode(D2, OUTPUT);
  pinMode(D3, OUTPUT);
  pinMode(D4, OUTPUT);
  pinMode(BPLUS, INPUT);
  pinMode(BMINUS, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  setDisplay();
  setNumber();
  displayNumber();
}

void setDisplay() {
  switch (display) {
    case 1:
      digitalWrite(D1, HIGH);
      digitalWrite(D2, LOW);
      digitalWrite(D3, LOW);
      digitalWrite(D4, LOW);
      display = 2;
      break;
    case 2:
      digitalWrite(D1, LOW);
      digitalWrite(D2, HIGH);
      digitalWrite(D3, LOW);
      digitalWrite(D4, LOW);
      display = 3;
      break;
    case 3:
      digitalWrite(D1, LOW);
      digitalWrite(D2, LOW);
      digitalWrite(D3, HIGH);
      digitalWrite(D4, LOW);
      display = 4;
      break;
    case 4:
      digitalWrite(D1, LOW);
      digitalWrite(D2, LOW);
      digitalWrite(D3, LOW);
      digitalWrite(D4, HIGH);
      display = 1;
      break;
  }
}

void setNumber() {
  if (digitalRead(BPLUS) == HIGH && num < 999) {
    num++;
    delay(250);
  }
  if (digitalRead(BMINUS) == HIGH && num > 0) {
    num--;
    delay(250);
  }
}

void displayNumber() {
  byte digit = getDigit();
  // set the latch pin on low to notify the 74HC595 chip it is receiving data
  digitalWrite(LATCH, LOW);
  // send the data of the digit at the index corresponding to the user's input (from 0 to 15)
  shiftOut(DATA, CLOCK, LSBFIRST, digit);
  // set the latch pin on high to notify the 74HC595 chip that it is no longer receiving data
  digitalWrite(LATCH, HIGH);
  delay(500);
}

byte getDigit() {
  int idx = 0;
  switch (display) {
    case 1:
      idx = (num / 1000) % 10; // sélectionne l'index du digit des milliers
      break;
    case 2:
      idx = (num / 100) % 10; // sélectionne l'index du digit des centaines
      break;
    case 3:
      idx = (num / 10) % 10; // sélectionne l'index du digit des dizaines
      break;
    case 4:
      idx = num % 10; // sélectionne l'index du digit des unités
      break;
  }
  byte d = digits[idx];
  Serial.print("display : ");
  Serial.print(display);
  Serial.print(" | num : ");
  Serial.print(num);
  Serial.print(" | idx : ");
  Serial.print(idx);
  Serial.print(" | d : ");
  Serial.print(d);
  Serial.print("\n");
  return d;
}