const int segmentPins[] = {6, 7, 8, 9, 10, 11, 12}; // A, B, C, D, E, F, G
const int digitPins[] = {2, 3, 4, 5};              // D1, D2, D3, D4 (Common pins)

// 7-segment encoding for digits 0-9 (common cathode)
const byte digitMap[10] = {
  B00111111, // 0
  B00000110, // 1
  B01011011, // 2
  B01001111, // 3
  B01100110, // 4
  B01101101, // 5
  B01111101, // 6
  B00000111, // 7
  B01111111, // 8
  B01101111  // 9
};

// Timer variables
unsigned long lastUpdateTime;
int remainingSeconds = 10 * 60 * 60; // 10 hours in seconds

void setup() {
  Serial.begin(9600); // For debugging

  // Initialize segment pins
  for (int i = 0; i < 7; i++) {
    pinMode(segmentPins[i], OUTPUT);
    digitalWrite(segmentPins[i], LOW); // All segments off initially
  }

  // Initialize digit pins
  for (int i = 0; i < 4; i++) {
    pinMode(digitPins[i], OUTPUT);
    digitalWrite(digitPins[i], HIGH); // All digits off initially
  }

  lastUpdateTime = millis(); // Record the start time
}

void loop() {
  // Update the countdown every second
  if (millis() - lastUpdateTime >= 1000) {
    lastUpdateTime += 1000; // Advance by 1 second
    if (remainingSeconds > 0) {
      remainingSeconds--; // Decrement time
    }
  }

  // Debugging: Print remaining time to Serial Monitor
  Serial.print("Remaining Time: ");
  Serial.println(remainingSeconds);

  // Calculate hours and minutes
  int hours = remainingSeconds / 3600;
  int minutes = (remainingSeconds % 3600) / 60;

  // Debugging: Print hours and minutes
  Serial.print("Hours: ");
  Serial.println(hours);
  Serial.print("Minutes: ");
  Serial.println(minutes);

  // Convert hours and minutes into individual digits
  int digit1 = hours / 10;    // Tens of hours
  int digit2 = hours % 10;    // Units of hours
  int digit3 = minutes / 10;  // Tens of minutes
  int digit4 = minutes % 10;  // Units of minutes

  // Display digits
  displayDigit(digit1, 0); // First digit (D1)
  displayDigit(digit2, 1); // Second digit (D2)
  displayDigit(digit3, 2); // Third digit (D3)
  displayDigit(digit4, 3); // Fourth digit (D4)
}

// Function to display a digit on a specific position
void displayDigit(int digit, int position) {
  // Turn off all digits
  for (int i = 0; i < 4; i++) {
    digitalWrite(digitPins[i], HIGH); // Turn off all digits
  }

  // Set segments for the desired digit
  for (int i = 0; i < 7; i++) {
    digitalWrite(segmentPins[i], bitRead(digitMap[digit], i));
  }

  // Enable the desired digit
  digitalWrite(digitPins[position], LOW);

  // Short delay for persistence of vision
  delay(5);
}