// Segment pins for 7-segment display (Common Cathode)
const int segmentPins[7] = {2, 3, 4, 5, 6, 7, 8}; // a–g

// Traffic light LEDs
const int redLED = 9;
const int yellowLED = 10;
const int greenLED = 11;

// Segment patterns for digits 0–9 [A,B,C,D,E,F,G]
const byte digitSegments[10][7] = {
  {1, 1, 1, 1, 1, 1, 0}, // 0
  {0, 1, 1, 0, 0, 0, 0}, // 1
  {1, 1, 0, 1, 1, 0, 1}, // 2
  {1, 1, 1, 1, 0, 0, 1}, // 3
  {0, 1, 1, 0, 0, 1, 1}, // 4
  {1, 0, 1, 1, 0, 1, 1}, // 5
  {1, 0, 1, 1, 1, 1, 1}, // 6
  {1, 1, 1, 0, 0, 0, 0}, // 7
  {1, 1, 1, 1, 1, 1, 1}, // 8
  {1, 1, 1, 1, 0, 1, 1}  // 9
};

void setup() {
  // 7-segment pins
  for (int i = 0; i < 7; i++) {
    pinMode(segmentPins[i], OUTPUT);
    digitalWrite(segmentPins[i], LOW);
  }

  // LED pins
  pinMode(redLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(greenLED, OUTPUT);

  // Start with all LEDs off
  digitalWrite(redLED, LOW);
  digitalWrite(yellowLED, LOW);
  digitalWrite(greenLED, LOW);

  // Serial for debugging
  Serial.begin(9600);
  Serial.println("Traffic Light Countdown Initialized");
}

void loop() {
  for (int i = 8; i >= 0; i--) {
    displayDigit(i); // show digit on 7-segment
    updateLEDs(i);   // light LEDs based on countdown
    Serial.print("Countdown: ");
    Serial.println(i);
    delay(1000); // wait 1 second
  }

  delay(3000); // pause before repeating

  // 👉 ADDITIONAL 8-second countdown with only pin 11 ON
  for (int i = 8; i >= 1; i--) {
    displayDigit(i);                 // Show countdown digit
    digitalWrite(redLED, HIGH);      // Ensure other LEDs are OFF
    digitalWrite(yellowLED,HIGH);
    digitalWrite(greenLED, LOW);   // Only pin 11 ON
    Serial.print("Red");
    Serial.println(i);
    delay(1000);
  }

  // Turn off all LEDs after extra countdown
  digitalWrite(greenLED, LOW);
}

// Light up 7-segment for a digit
void displayDigit(int digit) {
  for (int i = 0; i < 7; i++) {
    digitalWrite(segmentPins[i], digitSegments[digit][i]);
  }
}

// Set LED state based on countdown
void updateLEDs(int i) {
  if (i == 0) {
    digitalWrite(redLED, HIGH);
    digitalWrite(yellowLED, HIGH);
    digitalWrite(greenLED, LOW);
    Serial.println("Red ON");
  } else {
    digitalWrite(greenLED, HIGH); // 8–1

    if (i <= 3 && i >= 1) {
      digitalWrite(yellowLED, LOW); // 3–1
    } else {
      digitalWrite(yellowLED, HIGH);
    }

    digitalWrite(redLED, LOW); // Only ON at 0

    Serial.print("Green ON");
    if (i <= 3 && i >= 1) Serial.print(" | Yellow ON");
    Serial.println();
  }
}