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

LiquidCrystal_I2C lcd(0x27, 16, 2);

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}; // Pin baris keypad
byte colPins[COLS] = {5, 4, 3, 2}; // Pin kolom keypad// connect to the column pinouts of the keypad

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

String inputString = ""; // String to store entered characters
const int maxInput = 5; // Maximum input length

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Enter Input:");
}

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

  if (key) {
    if (key == 'C') {
      // Clear the input string
      inputString = "";
      clearLCD("Input Cleared");
    }
    else if (key == 'D') {
      // Delete the last character
      if (inputString.length() > 0) {
        inputString.remove(inputString.length() - 1);
      }
    }
    else {
      // Add the key to the string if it's not full
      if (inputString.length() < maxInput) {
        inputString += key;
      } else {
        displayErrorMessage("Max Input");
      }
    }
    printToLCD();
  }
}

void printToLCD() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(inputString);
}

void displayErrorMessage(const char *message) {
  lcd.setCursor(0, 1);
  lcd.print("Error: ");
  lcd.print(message);
  delay(2000); // Display the error message for 2 seconds
  lcd.setCursor(0, 1);
  lcd.print("                "); // Clear the error message
}

void clearLCD(const char *message) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(message);
  delay(2000); // Display the clear message for 2 seconds
  lcd.clear();
}