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

LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address, columns, rows

const byte ROWS = 4; //four rows
const byte COLS = 4; //four columns
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {9, 8, 7, 6}; //connect to the row pinouts of the keypad
byte colPins[COLS] = {5, 4, 3, 2}; //connect to the column pinouts of the keypad
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );

bool countdownRunning = false;
unsigned long countdownStartTime;
unsigned long countdownDuration = 600000;

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Countdown Timer");
  lcd.setCursor(0, 1);
  lcd.print("Press * to start");
}

void loop() {
  char key = keypad.getKey();

  if (key) {
    if (key == '*') {
      if (!countdownRunning) {
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Countdown Running");
        countdownStartTime = millis();
        countdownRunning = true;
      } else {
        // Stop the countdown if it's running
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Countdown Stopped");
        countdownRunning = false;
      }
    }

    // Handle other keys if needed

    // ...

  }

  if (countdownRunning) {
    unsigned long currentTime = millis();
    unsigned long elapsedTime = currentTime - countdownStartTime;
    unsigned long remainingTime = countdownDuration - elapsedTime;

    int hours = remainingTime / 3600000;
    int minutes = (remainingTime % 3600000) / 60000;
    int seconds = ((remainingTime % 3600000) % 60000) / 1000;

    lcd.setCursor(0, 1);
    lcd.print("Time: ");
    lcd.print(hours);
    lcd.print(":");
    lcd.print(minutes);
    lcd.print(":");
    lcd.print(seconds);

    if (remainingTime <= 0) {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Countdown Complete");
      countdownRunning = false;
    }
  }
}