/* Define shift register pins used for seven segment display */
#define LATCH_PIN 4
#define CLOCK_PIN 7
#define DATA_PIN 8

#define POT_PIN A0

/* Segment byte maps for numbers 0 to 9 */
const byte SEGMENT_MAP[] = {0xC0, 0xF9, 0xA4, 0xB0, 0x99, 0x92, 0x82, 0xF8, 0x80, 0x90};
/* Byte maps to select digit 1 to 4 */
const byte DIGIT_SELECT[] = {0xF1, 0xF2, 0xF4, 0xF8};

void setup() {
  Serial.begin(9600);
  /* Set DIO pins to outputs */
  pinMode(LATCH_PIN, OUTPUT);
  pinMode(CLOCK_PIN, OUTPUT);
  pinMode(DATA_PIN, OUTPUT);
}

/* Main program */
void loop() {
  int potValue = analogRead(POT_PIN);
  Serial.print("Potentiometer Value: ");
  Serial.println(potValue);

  /* Convert potValue to a 4-digit displayable number (0-9999) */
  int displayValue = map(potValue, 0, 1023, 0, 9999);

  /* Display the value with a scrolling effect */
  for (int i = 0; i < 4; i++) {
    DisplayDigitWithDelay(displayValue, 100);
  }
}

/* Function to display a value on all 4 digits with delay between updates */
void DisplayDigitWithDelay(int value, int delayTime) {
  WriteNumberToSegment(0, value / 1000);          // Extract thousands digit
  WriteNumberToSegment(1, (value / 100) % 10);   // Extract hundreds digit
  WriteNumberToSegment(2, (value / 10) % 10);    // Extract tens digit
  WriteNumberToSegment(3, value % 10);           // Extract units digit
  delay(delayTime);
}

/* Write a decimal number between 0 and 9 to one of the 4 digits of the display */
void WriteNumberToSegment(byte digit, byte value) {
  digitalWrite(LATCH_PIN, LOW);
  shiftOut(DATA_PIN, CLOCK_PIN, MSBFIRST, SEGMENT_MAP[value]);
  shiftOut(DATA_PIN, CLOCK_PIN, MSBFIRST, DIGIT_SELECT[digit]);
  digitalWrite(LATCH_PIN, HIGH);
}