//Define pins for LEDs
const int redLED = 8;
const int yellowLED = 9;
const int greenLED = 10;

// Define pin for the stop button 
const int stopButton = 2; // Connect the button to any digital pin

//Define delays (in milliseconds)
const int redDelay = 5000;   //Red light duration (5 seconds)
const int yellowDelay = 2000; //Yellow light duration (2 seconds)
const int greenDelay = 5000;  //Green light duration ( 5 seconds)
const int stopDelay = 10000;  //Stop button press duration (10 seconds)

// Define states for the traffic light
enum TrafficLightState {
  RED,
  YELLOW,
  GREEN,
  STOPPED
};

TrafficLightState currentState = RED; // Initial state

unsigned long previousMillis = 0; // Variable to store the time since the last state change
unsigned long stopMillis = 0; // Variable to store the time since the stop button press

void setup() {
  // Set LED pins as output
  pinMode(redLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(greenLED, OUTPUT);

  // Set button pin as input with pull-up resistor
  pinMode(stopButton, INPUT_PULLUP);
}

void loop() {
  unsigned long currentMillis = millis(); // Get the current time

  // Check if the stop button is pressed
  if (digitalRead(stopButton)== LOW) {
    stopMillis = currentMillis; // Record the time when the button was pressed
    currentState = STOPPED; // Set the state to stopped
}

// Handle traffic light states 
switch (currentState) {
  case RED:
  if (currentMillis - previousMillis >+ redDelay) {
    currentState = GREEN; // Transition to green
    previousMillis = currentMillis; // Update the previous state change time
  } 
  break;
  case YELLOW:
  if (currentMillis - previousMillis >= yellowDelay) {
    currentState = RED; // Transition to red
    previousMillis = currentMillis; // update the previous state change time
  }
  break;
  case STOPPED:
  if (currentMillis - stopMillis >= stopDelay) { 
    currentState = RED; // Resume traffic light cycle after stopDelay
    previousMillis = currentMillis; // Update the previous state change time
  } 
  break;
}

// Update the LEDs based on the current state
switch (currentState) {
  case RED:
  digitalWrite(redLED, HIGH);
  digitalWrite(yellowLED, LOW);
  digitalWrite(greenLED, LOW);
   break;
  case YELLOW:
  digitalWrite(redLED, LOW);
  digitalWrite(yellowLED, HIGH);
  digitalWrite(greenLED, LOW);
   break;
   case GREEN:
   digitalWrite(redLED, LOW);
   digitalWrite(yellowLED, LOW);
   digitalWrite(greenLED, HIGH);
    break;
    case STOPPED:
    digitalWrite(redLED, LOW);
    digitalWrite(yellowLED, LOW);
    digitalWrite(greenLED, LOW);
     break;
 }
}