// Traffic Light 1 LEDs
int tl1Red = 3;        
int tl1Yellow = 4;     
int tl1Green = 5;      

// Traffic Light 2 LEDs
int tl2Red = 6;         
int tl2Yellow = 7;      
int tl2Green = 8;   

//Pin Buttons
int pushButton[] = {2,9};
int buttons[] = {0,0};

// Current State
int currentState = 0;

// Delays
unsigned long start = 0;
unsigned long greenDel = 3000;         
unsigned long yellowDel = 1000;         
unsigned long greenDelPre = greenDel / 2;
unsigned long yellowDelPre = yellowDel / 1;

void setup() {
  // Traffic Lights 1
  pinMode(tl1Red, OUTPUT);      
  pinMode(tl1Yellow, OUTPUT);
  pinMode(tl1Green, OUTPUT);
  // Traffic Lights 2
  pinMode(tl2Red, OUTPUT);
  pinMode(tl2Yellow, OUTPUT);
  pinMode(tl2Green, OUTPUT);
  // PushButtons
  pinMode (pushButton[0], INPUT);
  pinMode (pushButton[1], INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  buttons[0] = digitalRead(pushButton[0]);
  buttons[1] = digitalRead(pushButton[1]);

  natSequence();
  bpSequence();
  if (buttons[0] == HIGH) {
    if (digitalRead(tl1Green) == HIGH) {
      currentState = 4;
    } else if (digitalRead(tl1Yellow) == HIGH) {
      currentState = 5;
    } 
    natSequence();
  } else if (buttons[1] == HIGH) {
    if (digitalRead(tl2Green) == HIGH) {
      currentState = 8;
    } else if (digitalRead(tl2Yellow) == HIGH) {
      currentState = 9;
    } 
    natSequence();
  } else {
    natSequence();
  }
}

void bpSequence() {
  unsigned long currentTime = millis();
  unsigned long elapsedTime = currentTime - start;

  // Button 1 Pressed
  if (currentState == 4) {
    if (elapsedTime < greenDelPre) {
      // Traffic Lights 1
      digitalWrite(tl1Red, LOW);
      digitalWrite(tl1Yellow, LOW);
      digitalWrite(tl1Green, HIGH);
      // Traffic Lights 2
      digitalWrite(tl2Red, HIGH);
      digitalWrite(tl2Yellow, LOW);
      digitalWrite(tl2Green, LOW);
    }
    else {
      currentState = 5;
      start = currentTime;
    }
  } else if (currentState == 5) {
    if (elapsedTime < yellowDelPre) {
      // Traffic Lights 1
      digitalWrite(tl1Green, LOW);
      digitalWrite(tl1Red, LOW);
      digitalWrite(tl1Yellow, HIGH);
    }
    else {
      currentState = 6;
      start = currentTime;
    }
  } else if (currentState == 6) {
    if (elapsedTime < greenDel) {
      // Traffic Lights 1
      digitalWrite(tl1Green, LOW);
      digitalWrite(tl1Yellow, LOW);
      digitalWrite(tl1Red, HIGH);
      // Traffic Lights 2
      digitalWrite(tl2Green, HIGH);
      digitalWrite(tl2Yellow, LOW);
      digitalWrite(tl2Red, LOW);
    } else {
      currentState = 7;
      start = currentTime;
    }
  } else if (currentState == 7) {
    if (elapsedTime < yellowDel) {
      digitalWrite(tl2Green, LOW);
      digitalWrite(tl2Red, LOW);
      digitalWrite(tl2Yellow, HIGH);
    } else {
      currentState = 0;
      start = currentTime;
    }
  }

  // Button 2 Pressed   
  if (currentState == 8) {
    if (elapsedTime < greenDelPre) {
      // Traffic Lights 1
      digitalWrite(tl2Red, LOW);
      digitalWrite(tl2Yellow, LOW);
      digitalWrite(tl2Green, HIGH);
      // Traffic Lights 2
      digitalWrite(tl1Red, HIGH);
      digitalWrite(tl1Yellow, LOW);
      digitalWrite(tl1Green, LOW);
    }
    else {
      currentState = 9;
      start = currentTime;
    }
  } else if (currentState == 9) {
    if (elapsedTime < yellowDelPre) {
      // Traffic Lights 1
      digitalWrite(tl2Green, LOW);
      digitalWrite(tl2Red, LOW);
      digitalWrite(tl2Yellow, HIGH);
    }
    else {
      currentState = 10;
      start = currentTime;
    }
  } else if (currentState == 10) {
    if (elapsedTime < greenDel) {
      // Traffic Lights 1
      digitalWrite(tl2Green, LOW);
      digitalWrite(tl2Yellow, LOW);
      digitalWrite(tl2Red, HIGH);
      // Traffic Lights 2
      digitalWrite(tl1Green, HIGH);
      digitalWrite(tl1Yellow, LOW);
      digitalWrite(tl1Red, LOW);
    } else {
      currentState = 11;
      start = currentTime;
    }
  } else if (currentState == 11) {
    if (elapsedTime < yellowDel) {
      // Traffic Lights 1
      digitalWrite(tl1Green, LOW);
      digitalWrite(tl1Red, LOW);
      digitalWrite(tl1Yellow, HIGH);
    } else {
      currentState = 12;
      start = currentTime;
    }
  } else if (currentState == 12) {
    if (elapsedTime < greenDel) {
      // Traffic Lights 1
      digitalWrite(tl1Green, LOW);
      digitalWrite(tl1Yellow, LOW);
      digitalWrite(tl1Red, HIGH);
      // Traffic Lights 2
      digitalWrite(tl2Green, HIGH);
      digitalWrite(tl2Yellow, LOW);
      digitalWrite(tl2Red, LOW);
    } else {
      currentState = 13;
      start = currentTime;
    }
  } else if (currentState == 13) {
    if (elapsedTime < yellowDel) {
      // Traffic Lights 1
      digitalWrite(tl1Green, LOW);
      digitalWrite(tl1Red, HIGH);
      digitalWrite(tl1Yellow, LOW);
    } else {
      currentState = 0;
      start = currentTime;
    }
  }
}

void natSequence() {
  unsigned long currentTime = millis();
  unsigned long elapsedTime = currentTime - start;

  if (currentState == 0) {
    if (elapsedTime < greenDel) {
      // Traffic Lights 1
      digitalWrite(tl1Red, LOW);
      digitalWrite(tl1Yellow, LOW);
      digitalWrite(tl1Green, HIGH);
      // Traffic Lights 2
      digitalWrite(tl2Red, HIGH);
      digitalWrite(tl2Yellow, LOW);
      digitalWrite(tl2Green, LOW);
    }
    else {
      currentState = 1;
      start = currentTime;
    }
  } else if (currentState == 1) {
    if (elapsedTime < yellowDel) {
      // Traffic Lights 1
      digitalWrite(tl1Green, LOW);
      digitalWrite(tl1Red, LOW);
      digitalWrite(tl1Yellow, HIGH);
    }
    else {
      currentState = 2;
      start = currentTime;
    }
  } else if (currentState == 2) {
    if (elapsedTime < greenDel) {
      // Traffic Lights 1
      digitalWrite(tl1Green, LOW);
      digitalWrite(tl1Yellow, LOW);
      digitalWrite(tl1Red, HIGH);
      // Traffic Lights 2
      digitalWrite(tl2Green, HIGH);
      digitalWrite(tl2Yellow, LOW);
      digitalWrite(tl2Red, LOW);
    } else {
      currentState = 3;
      start = currentTime;
    }
  } else if (currentState == 3) {
    if (elapsedTime < yellowDel) {
      digitalWrite(tl2Green, LOW);
      digitalWrite(tl2Red, LOW);
      digitalWrite(tl2Yellow, HIGH);
    } else {
      currentState = 0;
      start = currentTime;
    }
  }
}