#include <Servo.h>
#include <LiquidCrystal.h>
#include <Keypad.h>

#define ROWS 4
#define COLS 4
#define RS_PIN 9
#define E_PIN 8
#define D4_PIN 7
#define D5_PIN 6
#define D6_PIN 5
#define D7_PIN 4
#define SERVO_PIN 3
#define PASS_LEN 8

const char password[PASS_LEN] = "14523069";
const uint8_t ROW_PINS[ROWS] = {A0, A1, A2, A3};
const uint8_t COL_PINS[COLS] = {13, 12, 11, 10};
const char keymap[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'},
};

Keypad keypad = Keypad(makeKeymap(keymap), ROW_PINS, COL_PINS, ROWS, COLS);
LiquidCrystal lcd = LiquidCrystal(RS_PIN, E_PIN, D4_PIN, D5_PIN, D6_PIN, D7_PIN);
Servo servo;

uint8_t i = 0;
char passBuf[PASS_LEN];

bool equalString(char *a, char *b, uint32_t len) {
  for(int i = 0;  i < len; i++)
    if(a[i] != b[i]) return false;
  return true;
}

void setup() {
  servo.attach(SERVO_PIN);
  servo.write(0);
  lcd.begin(16, 2);
  lcd.clear();
  lcd.print("Password:");
  lcd.setCursor(0, 1);
}

void loop() {
  char key = keypad.getKey();
  if(key != NO_KEY) {
    lcd.print(key);
    passBuf[i++] = key;
    if(i == PASS_LEN) {
      if(equalString(passBuf, password, PASS_LEN)) {
        servo.write(90);
        lcd.clear();
        lcd.print("Welcome!");
      } else {
        lcd.clear();
        lcd.print("Incorrect!!!");
        delay(1000);
        lcd.clear();
        lcd.print("Password:");
        lcd.setCursor(0, 1);
        i = 0;
      }
    }
  }
}