#include <SoftwareSerial.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <Keypad.h>
#include<ESP32Servo.h>
#include <WiFi.h>

char ssid[] = "Wokwi-GUEST";
char password[] = "";

Servo servo;

#define BUZZER 4
#define trigPin 23
#define echoPin 19

int otp;
String otpstring = "";
int i = 0;


const byte ROWS = 4;
const byte COLS = 4;
char hexaKeys[ROWS][COLS] = {
  { '1', '2', '3', 'A' },
  { '4', '5', '6', 'B' },
  { '7', '8', '9', 'C' },
  { '*', '0', '#', 'D' }
};
byte rowPins[ROWS] = { 12,14,27,26};
byte colPins[COLS] = { 25,33,32,35};
Keypad customKeypad = Keypad(makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS);

LiquidCrystal_I2C lcd(0x27, 16, 2);
long distance;


void setup()
{
  Serial.begin(115200);
   lcd.init();
  lcd.backlight();
    lcd.clear();
  lcd.print("CONNECTING TO...");
  lcd.setCursor(0,1);
  lcd.print(ssid);
  delay(1000);
  
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi ..");
  while(WiFi.status()!= WL_CONNECTED)
  {
    Serial.print('.');
    delay(500);
  }
   

  Serial.println("READY");
  
  lcd.clear();
  lcd.print(" WIFI CONNECTED ");
  Serial.print(" WIFI CONNECTED ");
  pinMode(BUZZER,OUTPUT);
  digitalWrite(BUZZER,LOW);
  
  lcd.clear();
  lcd.print(" WIFI CONNECTED ");
  delay(2000);

  servo.attach(4);
  servo.write(90);
  delay(500);
 
}

void loop() {
lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("OTP BASED DOOR");
  lcd.setCursor(0, 1);
  lcd.print("LOCK USING IOT");

  // Check if someone is near the door using ultrasonic sensor
  measureDistance();

  if (distance <= 200) {
    activateAlarm();
  } else {
    deactivateAlarm();
  }

  char key = customKeypad.getKey();
  if (key) {
    if (isDigit(key) || key == '*') {
      lcd.clear();
      lcd.setCursor(0, 0);
      lcd.print("Enter OTP:");
      getotp();
    }
  }
}
void activateAlarm() {
  digitalWrite(BUZZER, HIGH); // Turn on the buzzer
}

void deactivateAlarm() {
  digitalWrite(BUZZER, LOW); // Turn off the buzzer
}

void measureDistance() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  distance = pulseIn(echoPin, HIGH) * 0.034 / 2; // Calculate distance in cm
}

void getotp() {

  String y = "";
  int a = y.length();
  while (a < 4) {
    char customKey = customKeypad.getKey();
    if (customKey)
    {
      lcd.setCursor(0, 1);
      y = y + customKey;
      lcd.print(y);
      a = y.length();
    }
  }
  Serial.print("Entered OTP is ");
  Serial.println(y);
  if (otpstring == y) {
    lcd.setCursor(0, 0);
    lcd.print("Access Granted");
    lcd.setCursor(0, 1);
    lcd.print("Door Opening");
    delay(2000);
    lcd.clear();
    lcd.print("* WELCOME *");
    delay(3000);
   for(i=90;i>=0;i--)
  {
    servo.write(i);
    delay(15);

   }
   delay(10000);
  for(i=0;i<=90;i++)
  {
    servo.write(i);
    delay(15);

   }
  } 
  else
  { 
    lcd.setCursor(0, 0);
    lcd.print("Access Failed");
    lcd.setCursor(0, 1);
    lcd.print("Try Again !!!");   
  digitalWrite(BUZZER,HIGH);
    delay(2000);
    digitalWrite(BUZZER,LOW);
    delay(3000);
   
  }
}