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

#define PIN_TRIG 9
#define PIN_ECHO 12
#define redLED 10
#define greenLED 13
#define timeDelay 5000

const uint8_t ROWS = 4;
const uint8_t COLS = 3;
char keys[ROWS][COLS] = {
  { '1', '2', '3',},
  { '4', '5', '6',},
  { '7', '8', '9',},
  { '*', '0', '#',}
};

uint8_t rowPins[ROWS] = { 8, 7, 6, 5 }; // Pins connected to R1, R2, R3, R4
uint8_t colPins[COLS] = { 4, 3, 2 }; // Pins connected to C1, C2, C3

Servo myservo;
LiquidCrystal_I2C lcd(0x27, 20, 4);
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

String password = "7777";
String enterPass = "";
bool passEntered;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  myservo.attach(11);
  lcd.init();

  pinMode(PIN_TRIG, OUTPUT);
  pinMode(PIN_ECHO, INPUT);
  pinMode(greenLED, OUTPUT);
  pinMode(redLED, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(PIN_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG, LOW);

  int duration = pulseIn(PIN_ECHO, HIGH);
  int distance = duration / 58;

  if(distance < 150) { // Sensor activated
    char key = keypad.getKey();
    lcd.backlight();

    if (passEntered == false) { // Input password
      lcd.setCursor(1, 1);
      lcd.print("ENTER PASSWORD :");
      passEntered = true;
    }

    if (key != NO_KEY) {
      if (key == '#') {
        if (password == enterPass) { // Password correct
          beep();
          digitalWrite(greenLED, HIGH);
          digitalWrite(redLED, LOW);
          myservo.write(0);
          
          lcd.clear();
          lcd.setCursor(1, 0);
          lcd.print("PASSWORD CORRECT");

          lcd.setCursor(1, 1);
          lcd.print("DOOR OPENED");

          delay(timeDelay);
          lcd.clear();
          reset();
        }
        else { // Password incorrect
          digitalWrite(greenLED, LOW);
          digitalWrite(redLED, HIGH);
          myservo.write(90);

          lcd.clear();
          lcd.setCursor(1, 0);
          lcd.print("PASSWORD INCORRECT");
          reset();
        }
      }
      else { // Input password
        enterPass += key;
        lcd.setCursor(1, 3);
        lcd.print(enterPass);
      }
    }
    
  } else { // Sensor inactive
    digitalWrite(greenLED, LOW);
    digitalWrite(redLED, LOW);
    myservo.write(90);

    lcd.clear();
    lcd.noBacklight();
    reset();
  }
}

void beep() {
  tone(8, 1000, 50);
}

void reset() {
  passEntered = false;
  enterPass = "";
}