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

LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C 位址根據模組設定

const byte ROWS = 4; // 鍵盤列數
const byte COLS = 4; // 鍵盤行數

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}; // 接腳設定依實際接法
byte colPins[COLS] = {5, 4, 3, 2};

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

String inputPassword = "";
String correctPassword = "1234";

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

void loop() {
  char key = keypad.getKey();
  if (key) {
    if (key == '#') { // 確認鍵
      lcd.clear();
      if (inputPassword == correctPassword) {
        lcd.print("Access Granted");
      } else {
        lcd.print("Access Denied");
      }
      delay(2000);
      inputPassword = "";
      lcd.clear();
      lcd.print("Enter Password:");
    } else if (key == '*') { // 清除鍵
      inputPassword = "";
      lcd.setCursor(0, 1);
      lcd.print("                "); // 清除第二行
    } else {
      if (inputPassword.length() < 16) {
        inputPassword += key;
        lcd.setCursor(inputPassword.length() - 1, 1);
        lcd.print("*");
      }
    }
  }
}