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


#define BUTTON_RED     2  
#define BUTTON_YELLOW  3   
#define BUTTON_GREEN   4   

// LED pins
#define LED_RED       10 
#define LED_YELLOW    11   
#define LED_GREEN     12  


#define BUZZER        15  


LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {

  Wire.setSDA(0);     
  Wire.setSCL(1);   
  Wire.begin();      

  lcd.init();         
  lcd.backlight();    
  lcd.setCursor(0, 0);
  lcd.print("System Ready");

 
  pinMode(BUTTON_RED,    INPUT_PULLUP);
  pinMode(BUTTON_YELLOW, INPUT_PULLUP);
  pinMode(BUTTON_GREEN,  INPUT_PULLUP);

  pinMode(LED_RED,    OUTPUT);
  pinMode(LED_YELLOW, OUTPUT);
  pinMode(LED_GREEN,  OUTPUT);

  pinMode(BUZZER, OUTPUT);
}

void loop() {
  if (digitalRead(BUTTON_RED) == LOW) {
    showMessage("STOP",   LED_RED,    1000);
  }
  else if (digitalRead(BUTTON_YELLOW) == LOW) {
    showMessage("READY",  LED_YELLOW, 500);
  }
  else if (digitalRead(BUTTON_GREEN) == LOW) {
    showMessage("GO",     LED_GREEN,  300);
  }
  else {
    
    digitalWrite(LED_RED,    LOW);
    digitalWrite(LED_YELLOW, LOW);
    digitalWrite(LED_GREEN,  LOW);
    noTone(BUZZER);
  }
}

void showMessage(const char* message, int ledPin, int toneFreq) {
  
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Traffic Light:");
  lcd.setCursor(0, 1);
  lcd.print(message);


  digitalWrite(LED_RED,    LOW);
  digitalWrite(LED_YELLOW, LOW);
  digitalWrite(LED_GREEN,  LOW);
  digitalWrite(ledPin,     HIGH);

 
  tone(BUZZER, toneFreq);
}