#include <LiquidCrystal_I2C.h>
#include <Wire.h>

#define ECHO_PIN1 12
#define TRIG_PIN1 11
#define ECHO_PIN2 A1
#define TRIG_PIN2 A0
#define ECHO_PIN3 A3
#define TRIG_PIN3 A2

#define RED1 2
#define YELLOW1 3
#define GREEN1 4
#define RED2 5
#define YELLOW2 6
#define GREEN2 7
#define RED3 8
#define YELLOW3 9
#define GREEN3 10

LiquidCrystal_I2C lcd(0x27, 16, 2);

int changes1 = 0;
int changes2 = 0;
int changes3 = 0;

void setup() {
  pinMode(RED1, OUTPUT);
  pinMode(YELLOW1, OUTPUT);
  pinMode(GREEN1, OUTPUT);
  pinMode(RED2, OUTPUT);
  pinMode(YELLOW2, OUTPUT);
  pinMode(GREEN2, OUTPUT);
  pinMode(RED3, OUTPUT);
  pinMode(YELLOW3, OUTPUT);
  pinMode(GREEN3, OUTPUT);
  
  pinMode(TRIG_PIN1, OUTPUT);
  pinMode(ECHO_PIN1, INPUT);
  pinMode(TRIG_PIN2, OUTPUT);
  pinMode(ECHO_PIN2, INPUT);
  pinMode(TRIG_PIN3, OUTPUT);
  pinMode(ECHO_PIN3, INPUT);

  lcd.begin();
  lcd.backlight();

  startTrafficLight(1);
}

void loop() {
  int distance1 = getDistance(TRIG_PIN1, ECHO_PIN1);
  int distance2 = getDistance(TRIG_PIN2, ECHO_PIN2);
  int distance3 = getDistance(TRIG_PIN3, ECHO_PIN3);

  if (distance1 < 20) {
    changeTrafficLight(1);
  } else if (distance2 < 20) {
    changeTrafficLight(2);
  } else if (distance3 < 20) {
    changeTrafficLight(3);
  }

  updateLCD();
}

void startTrafficLight(int light) {
  switch(light) {
    case 1:
      digitalWrite(RED1, LOW);
      digitalWrite(YELLOW1, LOW);
      digitalWrite(GREEN1, HIGH);
      digitalWrite(RED2, HIGH);
      digitalWrite(YELLOW2, LOW);
      digitalWrite(GREEN2, LOW);
      digitalWrite(RED3, HIGH);
      digitalWrite(YELLOW3, LOW);
      digitalWrite(GREEN3, LOW);
      break;
    case 2:
      digitalWrite(RED1, HIGH);
      digitalWrite(YELLOW1, LOW);
      digitalWrite(GREEN1, LOW);
      digitalWrite(RED2, LOW);
      digitalWrite(YELLOW2, LOW);
      digitalWrite(GREEN2, HIGH);
      digitalWrite(RED3, HIGH);
      digitalWrite(YELLOW3, LOW);
      digitalWrite(GREEN3, LOW);
      break;
    case 3:
      digitalWrite(RED1, HIGH);
      digitalWrite(YELLOW1, LOW);
      digitalWrite(GREEN1, LOW);
      digitalWrite(RED2, HIGH);
      digitalWrite(YELLOW2, LOW);
      digitalWrite(GREEN2, LOW);
      digitalWrite(RED3, LOW);
      digitalWrite(YELLOW3, LOW);
      digitalWrite(GREEN3, HIGH);
      break;
  }
}

void changeTrafficLight(int light) {
  if (light == 1) {
    startTrafficLight(1);
    changes1++;
    delay(10000); // wait for 10 seconds
  } else if (light == 2) {
    startTrafficLight(2);
    changes2++;
    delay(10000); // wait for 10 seconds
  } else if (light == 3) {
    startTrafficLight(3);
    changes3++;
    delay(10000); // wait for 10 seconds
  }
}

int getDistance(int trigPin, int echoPin) {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  long duration = pulseIn(echoPin, HIGH);
  int distance = duration * 0.034 / 2;
  return distance;
}

void updateLCD() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("S1:");
  lcd.print(changes1);
  lcd.setCursor(6, 0);
  lcd.print("S2:");
  lcd.print(changes2);
  lcd.setCursor(12, 0);
  lcd.print("S3:");
  lcd.print(changes3);
}