#define RED_LED    2
#define YELLOW_LED 4
#define GREEN_LED  5

// Traffic light phase durations (milliseconds)
#define GREEN_TIME   4000   // 4 seconds green
#define YELLOW_TIME  1500   // 1.5 seconds yellow (caution)
#define RED_TIME     4000   // 4 seconds red

// Helper: turn all LEDs off
void allOff() {
  digitalWrite(RED_LED,    LOW);
  digitalWrite(YELLOW_LED, LOW);
  digitalWrite(GREEN_LED,  LOW);
}

void setup() {
  Serial.begin(115200);

  // Configure all three pins as outputs
  pinMode(RED_LED,    OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(GREEN_LED,  OUTPUT);

  allOff();  // Start with all LEDs off

  Serial.println("Traffic Light simulation started.");
  Serial.println("Simulating: Model Town Rd, Lahore");
}

void loop() {
  // --- PHASE 1: GREEN (vehicles may proceed) ---
  allOff();
  digitalWrite(GREEN_LED, HIGH);
  Serial.printf("GREEN ON  — go! (%d ms)\n", GREEN_TIME);
  delay(GREEN_TIME);

  // --- PHASE 2: YELLOW (prepare to stop) ---
  allOff();
  digitalWrite(YELLOW_LED, HIGH);
  Serial.printf("YELLOW ON — slow down! (%d ms)\n", YELLOW_TIME);
  delay(YELLOW_TIME);

  // --- PHASE 3: RED (stop) ---
  allOff();
  digitalWrite(RED_LED, HIGH);
  Serial.printf("RED ON    — stop! (%d ms)\n", RED_TIME);
  delay(RED_TIME);
}