const int redLedPin = 2, yellowLedPin = 3, greenLedPin = 4, pedestrianLedPin = 7;
const int buttonPin = 6, buzzerPin = 5, trigPin = 12, echoPin = 11;
bool pedestrianCrossing = false;

void setup() {
  pinMode(redLedPin, OUTPUT); pinMode(yellowLedPin, OUTPUT); pinMode(greenLedPin, OUTPUT);
  pinMode(pedestrianLedPin, OUTPUT); pinMode(buttonPin, INPUT_PULLUP);
  pinMode(buzzerPin, OUTPUT); pinMode(trigPin, OUTPUT); pinMode(echoPin, INPUT);
  Serial.begin(9600);
}

void loop() {
  if (!pedestrianCrossing) trafficLightSequence();
  if (digitalRead(buttonPin) == LOW) handlePedestrianCrossing();

  if (pedestrianCrossing) {
    int distance = measureDistance();
    digitalWrite(pedestrianLedPin, HIGH);
    digitalWrite(redLedPin, HIGH);
    Serial.print("Distance: "); Serial.println(distance);
    if (distance <= 10) tone(buzzerPin, 150);
    else noTone(buzzerPin);
  }
  delay(100);
}

void trafficLightSequence() {
  digitalWrite(pedestrianLedPin, LOW);
  digitalWrite(redLedPin, HIGH); Serial.println("Traffic Light: RED"); delay(5000);
  digitalWrite(redLedPin, LOW); digitalWrite(yellowLedPin, HIGH); Serial.println("Traffic Light: YELLOW"); delay(2000);
  digitalWrite(yellowLedPin, LOW); digitalWrite(greenLedPin, HIGH); Serial.println("Traffic Light: GREEN"); delay(5000);
  digitalWrite(greenLedPin, LOW); digitalWrite(yellowLedPin, HIGH); delay(2000);
  digitalWrite(yellowLedPin, LOW); pedestrianCrossing = true;
}

void handlePedestrianCrossing() {
  digitalWrite(redLedPin, HIGH); Serial.println("Pedestrian Light: OFF, Traffic Light: RED"); delay(7000);
  digitalWrite(pedestrianLedPin, HIGH); Serial.println("Pedestrian Light: GREEN, Traffic Light: RED"); delay(7000);
  pedestrianCrossing = false;
}

int measureDistance() {
  digitalWrite(trigPin, LOW); delayMicroseconds(2);
  digitalWrite(trigPin, HIGH); delayMicroseconds(10);
  return pulseIn(echoPin, HIGH) * 0.034 / 2;
}