#include <Password.h>                             
#include <EEPROM.h>  
#include <Keypad.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 21);
const char ROWS = 4;
const char COLS = 3;
char keys[ROWS][COLS] = {
  {'1', '2', '3'},
  {'4', '5', '6'},
  {'7', '8', '9'},
  {'*', '0', '#'}
};
byte rowPin[ROWS] = {9, 8, 7, 6};
byte colPin[COLS] = {5, 4, 3};
Keypad keypad = Keypad(makeKeymap(keys), rowPin, colPin, ROWS, COLS);

char initial_password[4],new_password[4];
char password[4];
int l=0;
char key_pressed=0;
void setup()
{
  Serial.begin(9600);
  lcd.begin();
  lcd.backlight(); // เปิดไฟ backlight
  lcd.setCursor(0, 0);
  lcd.print("Enter Password");
  lcd.setCursor(0, 1);
  initialpassword();
  
}
void loop()
{
  key_pressed = keypad.getKey();
  if(key_pressed=='#')
  change();
  if (key_pressed)
  {
    password[l++]=key_pressed;
    lcd.print(key_pressed);
  }
  if(l==4)
  {
    delay(200);
    for(int p=0;p<4;p++)
    initial_password[p]=EEPROM.read(p);
    if(!(strncmp(password, initial_password,4)))
    {
      lcd.clear();
      lcd.print("Pass Accepted");
      delay(2000);
      lcd.setCursor(0,1);
      lcd.print("Pres # to change");
      delay(2000);
      lcd.clear();
      lcd.print("Enter Password:");
      lcd.setCursor(0,1);
      l=0;
    }
    else
    {
        lcd.clear();
        lcd.print("Wrong Password");
        lcd.setCursor(0,1);
        lcd.print("Pres # to Change");
        delay(2000);
        lcd.clear();
        lcd.print("Enter Password");
        lcd.setCursor(0,1);
        l=0;
    }
  }
}
void change()
{
  int p=0;
  lcd.clear();
  lcd.print("Current Password");
  lcd.setCursor(0,1);
  while(p<4)
  {
    char key=keypad.getKey();
    if(key)
    {
      new_password[p++]=key;
      lcd.print(key);    
    }
    key=0;
  }
  delay(500);
  if((strncmp(new_password, initial_password, 4)))
  {
      lcd.clear();
      lcd.print("Wrong Password");
      lcd.setCursor(0,1);
      lcd.print("Try Again");
      delay(1000);
  }
  else
  {
    p=0;
    lcd.clear();
    lcd.print("New Password:");
    lcd.setCursor(0,1);
    while(p<4)
    {
      char key=keypad.getKey();
      if(key)
      {
        initial_password[p]=key;
        lcd.print(key);
        EEPROM.write(p,key);
        p++;
      }
    }
    lcd.print("Pass Changed");
    delay(1000);
  }
    lcd.clear();
    lcd.print("Enter Password");
    lcd.setCursor(0,1);
    key_pressed=0;
}
void initialpassword(){
  for(int p=0;p<4;p++)
  EEPROM.write(p, p+49);
  for(int p=0;p<4;p++)
  initial_password[p]=EEPROM.read(p);
}