/*
Wokwi | questions
beans OP — 9/28/24 at 6:17 AM
need help from the program
https://wokwi.com/projects/410261587790308353
*/

const unsigned long INTERVAL = 1000;

// Define the pin connections for the 7-segment display
const int digitPins[] = {8, 11, 12, 2}; // Pins for digit 1, 2, 3, and 4
const int segmentPins[] = {9, 13, 4, 6, 7, 10, 3, 5}; // Pins for segments A, B, C, D, E, F, G, and DP

// Define the bit patterns for each digit (0-9)
const byte digitPatterns[] = {
  B11111100, // 0
  B01100000, // 1
  B11011010, // 2
  B11110010, // 3
  B01100110, // 4
  B10110110, // 5
  B10111110, // 6
  B11100000, // 7
  B11111110, // 8
  B11110110, // 9
};

unsigned long prevTime = 0;

void setup() {
  Serial.begin(115200);
  // Initialize the digit pins as outputs
  for (int i = 0; i < 4; i++) {
    pinMode(digitPins[i], OUTPUT);
  }
  // Initialize the segment pins as outputs
  for (int i = 0; i < 7; i++) {
    pinMode(segmentPins[i], OUTPUT);
  }
}

void loop() {
  // Start the countdown from 99
  int countdown = 99;
  
  while (countdown >= 0) {
    // Display the current countdown value
    displayCountdown(countdown);
    
    if (millis() - prevTime >= INTERVAL)  {
      prevTime = millis();
    // Decrement the countdown value
    countdown--;
    //Serial.println(countdown);
    }
    // Wait for 1 second before updating the display again
    //delay(1000);
  }
}

void displayCountdown(int countdown) {
  // Extract the individual digits from the countdown value
  int digit1 = countdown / 1000;
  int digit2 = (countdown % 1000) / 100;
  int digit3 = (countdown % 100) / 10;
  int digit4 = countdown % 10;
  
  // Display each digit on the 7-segment display
  displayDigit(digitPins[0], digit1);
  displayDigit(digitPins[1], digit2);
  displayDigit(digitPins[2], digit3);
  displayDigit(digitPins[3], digit4);
}

void displayDigit(int digitPin, int digitValue) {
  // Turn off all segments
  for (int i = 0; i <= 7; i++) {
    digitalWrite(segmentPins[i], HIGH);
  }
  
  // Turn on the segments for the current digit value
  byte pattern = digitPatterns[digitValue];
  for (int i = 0; i <= 7; i++) {
    if (bitRead(pattern, i)) {
      digitalWrite(segmentPins[7 - i], LOW);  // bitRead is LSB first
    }
  }
  
  // Turn on the digit pin
  digitalWrite(digitPin, HIGH);
  delay(5); // Hold the digit on for 5ms
  digitalWrite(digitPin, LOW);
}