int red1 = 2;
int yellow1 = 3;
int green1 = 4;
int red2 = 5;
int yellow2 = 6;
int green2 = 7;
int red3 = 8;
int yellow3 = 9;
int green3 = 10;
int red4 = 11;
int yellow4 = 12;
int green4 = 13;

int emergencySwitch1Pin = 18;  // INT0
int emergencySwitch2Pin = 19;  // INT1
int emergencySwitch3Pin = 20; // INT5
int emergencySwitch4Pin = 21; // INT4

volatile bool emergencyFlag = false;
volatile int emergencyDirection = 0;

void setup() {
  for (int i = 2; i <= 13; i++) {
    pinMode(i, OUTPUT);
  }
  
  pinMode(emergencySwitch1Pin, INPUT);
  pinMode(emergencySwitch2Pin, INPUT);
  pinMode(emergencySwitch3Pin, INPUT);
  pinMode(emergencySwitch4Pin, INPUT);
  
  attachInterrupt(digitalPinToInterrupt(emergencySwitch1Pin), emergencyISR1, FALLING);
  attachInterrupt(digitalPinToInterrupt(emergencySwitch2Pin), emergencyISR2, FALLING);
  attachInterrupt(digitalPinToInterrupt(emergencySwitch3Pin), emergencyISR3, FALLING);
  attachInterrupt(digitalPinToInterrupt(emergencySwitch4Pin), emergencyISR4, FALLING);
}

void loop() {
  if (emergencyFlag) {
    handleEmergency(emergencyDirection);
    emergencyFlag = false;
  } else {
    normalOperation();
  }
}

void emergencyISR1() {
  emergencyFlag = true;
  emergencyDirection = 1;
}

void emergencyISR2() {
  emergencyFlag = true;
  emergencyDirection = 2;
}

void emergencyISR3() {
  emergencyFlag = true;
  emergencyDirection = 3;
}

void emergencyISR4() {
  emergencyFlag = true;
  emergencyDirection = 4;
}

void handleEmergency(int direction) {
  allLightsOff();
  
  switch (direction) {
    case 1:
      digitalWrite(green1, HIGH);
      digitalWrite(red2, HIGH);
      digitalWrite(red3, HIGH);
      digitalWrite(red4, HIGH);
      break;
    case 2:
      digitalWrite(green2, HIGH);
      digitalWrite(red1, HIGH);
      digitalWrite(red3, HIGH);
      digitalWrite(red4, HIGH);
      break;
    case 3:
      digitalWrite(green3, HIGH);
      digitalWrite(red1, HIGH);
      digitalWrite(red2, HIGH);
      digitalWrite(red4, HIGH);
      break;
    case 4:
      digitalWrite(green4, HIGH);
      digitalWrite(red1, HIGH);
      digitalWrite(red2, HIGH);
      digitalWrite(red3, HIGH);
      break;
  }
}

void normalOperation() {
  direction(red1, yellow1, green1, red2, yellow2, green2, red3, yellow3, green3, red4, yellow4, green4);
  direction(red2, yellow2, green2, red1, yellow1, green1, red3, yellow3, green3, red4, yellow4, green4);
  direction(red3, yellow3, green3, red1, yellow1, green1, red2, yellow2, green2, red4, yellow4, green4);
  direction(red4, yellow4, green4, red1, yellow1, green1, red2, yellow2, green2, red3, yellow3, green3);
}

void allLightsOff() {
  for (int i = 2; i <= 13; i++) {
    digitalWrite(i, LOW);
  }
}

void direction(int a, int b, int c, int d, int e, int f, int g, int h, int i, int j, int k, int l) {
  digitalWrite(a, LOW);
  digitalWrite(b, LOW);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, HIGH);
  digitalWrite(h, LOW);
  digitalWrite(i, LOW);
  digitalWrite(j, HIGH);
  digitalWrite(k, LOW);
  digitalWrite(l, LOW);
  delay(5000);
  digitalWrite(c, LOW);
  digitalWrite(b, HIGH);
  delay(3000);
}