// Define pin numbers
const int nsweRedPin = 15;
const int nsweGreenPin = 16;

const int nsTrafficRedPin = 2;
const int nsTrafficYellowPin = 3;
const int nsTrafficGreenPin = 4;
const int weTrafficRedPin = 11;
const int weTrafficYellowPin = 12;
const int weTrafficGreenPin = 13;

const int button1Pin = 17;

// Timing constants
const unsigned long trafficGreenTime = 5000;
const unsigned long trafficYellowTime = 2000;
const unsigned long pedestrianGreenTime = 5000;
const unsigned long allRedPauseTime = 3000;

// State machine variables
unsigned long previousMillis = 0;
unsigned long stateDuration = 0;
int state = 0;

bool pedestrianRequest = false;

void setup() {
  Serial.begin(9600);

  pinMode(nsweRedPin, OUTPUT);
  pinMode(nsweGreenPin, OUTPUT);

  pinMode(nsTrafficRedPin, OUTPUT);
  pinMode(nsTrafficYellowPin, OUTPUT);
  pinMode(nsTrafficGreenPin, OUTPUT);
  pinMode(weTrafficRedPin, OUTPUT);
  pinMode(weTrafficYellowPin, OUTPUT);
  pinMode(weTrafficGreenPin, OUTPUT);

  pinMode(button1Pin, INPUT_PULLUP);

  turnOffAll();
}

void loop() {
  checkPedestrianRequest();
  updateTrafficLights();
}

void checkPedestrianRequest() {
  if (digitalRead(button1Pin) == LOW) {
    pedestrianRequest = true;
    Serial.println("Pedestrian button pressed - request latched!");
    delay(500); // basic debounce
  }
}

void updateTrafficLights() {
  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= stateDuration) {
    previousMillis = currentMillis;

    switch (state) {
      case 0: // NS Green, WE Red
        turnOffAll();
        digitalWrite(nsTrafficGreenPin, HIGH);
        digitalWrite(weTrafficRedPin, HIGH);
        stateDuration = trafficGreenTime;
        state = 1;
        break;

      case 1: // NS Yellow
        digitalWrite(nsTrafficGreenPin, LOW);
        digitalWrite(nsTrafficYellowPin, HIGH);
        stateDuration = trafficYellowTime;
        state = 2;
        break;

      case 2: // WE Green, NS Red
        digitalWrite(nsTrafficYellowPin, LOW);
        digitalWrite(nsTrafficRedPin, HIGH);
        digitalWrite(weTrafficRedPin, LOW);
        digitalWrite(weTrafficGreenPin, HIGH);
        stateDuration = trafficGreenTime;
        state = 3;
        break;

      case 3: // WE Yellow
        digitalWrite(weTrafficGreenPin, LOW);
        digitalWrite(weTrafficYellowPin, HIGH);
        stateDuration = trafficYellowTime;
        state = 4;
        break;

      case 4: // All Red pause
        digitalWrite(weTrafficYellowPin, LOW);
        digitalWrite(weTrafficRedPin, HIGH);
        stateDuration = allRedPauseTime;
        state = (pedestrianRequest) ? 5 : 0; // If request, go to pedestrian crossing
        break;

      case 5: // Pedestrian Crossing
        activatePedestrianCrossing();
        pedestrianRequest = false;
        state = 0;
        break;
    }
  }
}

void activatePedestrianCrossing() {
  turnOffAll();
  digitalWrite(nsTrafficRedPin, HIGH);
  digitalWrite(weTrafficRedPin, HIGH);
  delay(1000);

  digitalWrite(nsweRedPin, LOW);
  digitalWrite(nsweGreenPin, HIGH);
  delay(pedestrianGreenTime);

  // Flash pedestrian red
  for (int i = 0; i < 5; i++) {
    digitalWrite(nsweGreenPin, LOW);
    digitalWrite(nsweRedPin, HIGH);
    delay(300);
    digitalWrite(nsweRedPin, LOW);
    delay(300);
  }

  digitalWrite(nsweGreenPin, LOW);
  digitalWrite(nsweRedPin, HIGH);
  delay(1000);
}

void turnOffAll() {
  digitalWrite(nsTrafficRedPin, LOW);
  digitalWrite(nsTrafficYellowPin, LOW);
  digitalWrite(nsTrafficGreenPin, LOW);
  digitalWrite(weTrafficRedPin, LOW);
  digitalWrite(weTrafficYellowPin, LOW);
  digitalWrite(weTrafficGreenPin, LOW);
  digitalWrite(nsweRedPin, HIGH);
  digitalWrite(nsweGreenPin, LOW);
}