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

LiquidCrystal_I2C lcd(0x27,16,2);

const int buttonPin = 2;
const int buzzerPin = 3;

int parkingTime = 0;          // in minutes
float ratePerMinute = 15.0;   // ₹15 per minute
unsigned long lastMillis = 0;

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(buzzerPin, OUTPUT);
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Parking Meter");
  updateDisplay();
  delay (300);
}

void loop() {
  if (digitalRead(buttonPin) == LOW) {
    parkingTime++;
    updateDisplay();
    delay(300);
  }

  if (parkingTime > 0 && millis() - lastMillis >= 60000) {
    parkingTime--;
    updateDisplay();
    lastMillis = millis();
  }

  if (parkingTime == 0) {
    tone(buzzerPin, 1000);
  } else {
    noTone(buzzerPin);
  }
}

void updateDisplay() {
  float fare = parkingTime * ratePerMinute;
  lcd.setCursor(0,0);
  lcd.print("Time: ");
  lcd.print(parkingTime);
  lcd.print(" min  ");
  lcd.setCursor(0,1);
  lcd.print("Fare: Rs.");
  lcd.print(fare, 2);
  lcd.print("   ");
}