#define RED_PIN_1 12
#define GREEN_PIN_1 11
#define YELLOW_PIN_1 10
#define RED_PIN_2 7
#define GREEN_PIN_2 6
#define YELLOW_PIN_2 5

#define BUTTON_1_PIN 9
#define BUTTON_2_PIN 8

#define GREEN_DELAY 4000
#define YELLOW_DELAY 1000

// Setting up the parameters for the state of each switch
int buttonState1 = 0;
int buttonState2 = 0;

int button1PressTime = 0; // Time that switch 1 was pressed
int button2PressTime = 0; // TIme that switch 2 was pressed

// Booleans to check if button has been pressed
bool button1Pressed = false;
bool button2Pressed = false;

void setup() {
  // Setting up output pins for Traffic light 1
  pinMode(RED_PIN_1, OUTPUT);
  pinMode(GREEN_PIN_1, OUTPUT);
  pinMode(YELLOW_PIN_1, OUTPUT);

  // Setting up output pins for Traffic light 2
  pinMode(RED_PIN_2, OUTPUT);
  pinMode(GREEN_PIN_2, OUTPUT);
  pinMode(YELLOW_PIN_2, OUTPUT);

  // Seeting up the buttons for pedestrians
  pinMode(BUTTON_1_PIN, INPUT);
  pinMode(BUTTON_2_PIN, INPUT);

}

void loop() {
  // put your main code here, to run repeatedly:
  buttonState1 = digitalRead(BUTTON_1_PIN);
  buttonState2 = digitalRead(BUTTON_2_PIN);

  // Checking if the switch 1 has been pressed to change traffic light
  if (buttonState1 == HIGH && !button1Pressed) {
    changeLights(RED_PIN_1, RED_PIN_2, YELLOW_PIN_1, YELLOW_PIN_2, GREEN_PIN_1, GREEN_PIN_2);
    button1Pressed = true;
  }
  else if (buttonState1 == LOW) {
    button1Pressed = false;
  }

  if (buttonState2 == HIGH && !button2Pressed) {
    changeLights(RED_PIN_2, RED_PIN_1, YELLOW_PIN_2, YELLOW_PIN_1, GREEN_PIN_2, GREEN_PIN_1);
    button2Pressed = true;
  }
  else if (buttonState2 == LOW) {
    button2Pressed = false;
  }

  // First interval
  digitalWrite(RED_PIN_1, HIGH);    // Turn on first red light
  digitalWrite(GREEN_PIN_2, HIGH);  // Turn on second green light

  digitalWrite(RED_PIN_2, LOW);     // Turn off second red light
  digitalWrite(GREEN_PIN_1, LOW);   // Turn off first green light
  digitalWrite(YELLOW_PIN_1, LOW);  // Turn off first yellow light
  digitalWrite(YELLOW_PIN_2, LOW);  // Turn off second yellow light
  nonBlockDelay(GREEN_DELAY);       // Wait for the next round

  // Second interval
  digitalWrite(YELLOW_PIN_2, HIGH); // Turn on second yellow light
  digitalWrite(RED_PIN_1, HIGH);    // Turn on first red light

  digitalWrite(GREEN_PIN_1, LOW);   // Turn off second green light
  digitalWrite(GREEN_PIN_2, LOW);   // Turn off second green light
  digitalWrite(YELLOW_PIN_1, LOW);  // Turn off first yellow light
  digitalWrite(RED_PIN_2, LOW);     // Turn off second yellow light
  nonBlockDelay(YELLOW_DELAY);      // Wait for the next round

  // Third interval
  digitalWrite(RED_PIN_2, HIGH);    // Turn on second red light
  digitalWrite(GREEN_PIN_1, HIGH);  // Turn on first green light

  digitalWrite(YELLOW_PIN_2, LOW);  // Turn off second yellow light
  digitalWrite(RED_PIN_1, LOW);     // Turn off second red light
  digitalWrite(YELLOW_PIN_1, LOW);  // Turn off first yellow light
  digitalWrite(GREEN_PIN_2, LOW);   // Turn off second green light
  nonBlockDelay(GREEN_DELAY);       // Wait for the next round

  // Fourth and final interval
  digitalWrite(YELLOW_PIN_1, HIGH); // Turn on first yellow light
  digitalWrite(RED_PIN_2, HIGH);    // Turn on second red light

  digitalWrite(GREEN_PIN_1, LOW);   // Turn off first green light
  digitalWrite(GREEN_PIN_2, LOW);   // Turn off second green light
  digitalWrite(YELLOW_PIN_2, LOW);  // Turn off second yellow light
  digitalWrite(RED_PIN_1, LOW);     // Turn off first red light
  nonBlockDelay(YELLOW_DELAY);      // Loop back to the beginning

}

void changeLights(int RED1, int RED2, int YELLOW1, int YELLOW2, int GREEN1, int GREEN2) {
  // Function for RESET each of the traffic lights upon switch press
  
  // For the first interval
  digitalWrite(YELLOW2, HIGH);  // Turn on opposite yellow light
  digitalWrite(RED1, HIGH);     // Turn on adjacent red light

  digitalWrite(YELLOW1, LOW);   // Turn off adjacent yellow light
  digitalWrite(RED2, LOW);      // Turn off opposite red light
  digitalWrite(GREEN1, LOW);    // Turn off adjacent green light
  digitalWrite(GREEN2, LOW);    // Turn off opposite green light
  delay(YELLOW_DELAY);          // Set the time for opposite yellow light

  // For the second interval
  digitalWrite(GREEN1, HIGH);   // Turn on adjacent green light
  digitalWrite(RED2, HIGH);     // Turn on opposite red light

  digitalWrite(RED1, LOW);      // Turn off adjacent red light
  digitalWrite(GREEN2, LOW);    // Turn off opposite green light
  digitalWrite(YELLOW1, LOW);   // Turn off adjacent yellow light
  digitalWrite(YELLOW2, LOW);   // Turn off opposite yellow light
  delay(GREEN_DELAY);           // Set the time for adjacent green light

  // For the third interval
  digitalWrite(RED2, HIGH);     // Turn on opposite red light
  digitalWrite(YELLOW1, HIGH);  // Turn on adjacent yellow light

  digitalWrite(GREEN1, LOW);    // Turn off adjacent green light
  digitalWrite(GREEN2, LOW);    // Turn off opposite green light
  digitalWrite(RED1, LOW);      // Turn off adjacent red light
  digitalWrite(YELLOW2, LOW);   // Turn off opposite yellow light
  delay(YELLOW_DELAY);          // Set the time for adjacent yellow light

  // For the fourth and final interval
  digitalWrite(RED1, HIGH);     // Turn on adjacent red light
  digitalWrite(GREEN2, HIGH);   // Turn on opposite green light

  digitalWrite(RED2, LOW);      // Turn off opposite red light
  digitalWrite(GREEN1, LOW);    // Turn off adjacent green light
  digitalWrite(YELLOW1, LOW);   // Turn off adjacent yellow light
  digitalWrite(YELLOW2, LOW);   // Turn off opposite yellow light
  delay(2000);                  // Setting the final delay before reset

  // Reset traffic cycle after the switch has been pressed 
  digitalWrite(RED1, LOW);
  digitalWrite(GREEN2, LOW);
  delay(2000);
}

// Credits to ChatGPT for this function
void nonBlockDelay(unsigned long interval) {

  // Creating a non-modifiable beginning time
  static unsigned long previousMillis = 0;
  unsigned char currentMillis = millis();

  if (currentMillis - previousMillis <= interval) {
    previousMillis = currentMillis;
  }
}