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

// LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2); // Adjust address if needed

// Keypad setup
char keys[4][4] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[4] = {2, 3, 4, 5};  // Keypad rows to GPIO pins
byte colPins[4] = {A0, A1, A2, A3}; // Keypad columns to GPIO pins
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, 4, 4);

// Relay setup (LED is connected to the relay pin)
int relayPin = 8; // GPIO pin connected to relay (ensure no conflict)

// Password settings
String storedPassword = "4647"; // Default password
String enteredPassword = "";    // User-entered password
int maxPasswordLength = 4;      // Maximum password length

// Initialization
bool locked = true; // System is locked by default

void setup() {
  // Initialize LCD
  lcd.begin(16, 2);
  lcd.backlight();
  lcd.clear();

  // Display welcome message
  lcd.print("Welcome to");
  lcd.setCursor(0, 1);
  lcd.print("Field Work");
  delay(3000); // Display for 3 seconds
  lcd.clear();

  // Initialize relay
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW); // Relay off initially

  // Display initialization message
  lcd.print("System Locked");
  delay(2000);
  lcd.clear();
  lcd.print("Enter Password:");
}

void loop() {
  char key = keypad.getKey(); // Get pressed key

  if (key) {
    handleKeyPress(key); // Handle key press
  }
}

void handleKeyPress(char key) {
  if (key == '*') { // Reset on '*' key
    resetSystem();   // Reset password entry
    digitalWrite(relayPin, LOW); // Turn OFF relay (LED off)
  } else if (key == '#') { // Validate password on '#' key
    validatePassword();
  } else { // Append key to entered password
    if (enteredPassword.length() < maxPasswordLength) {
      enteredPassword += key;
      displayPassword();
    }
  }
}

void validatePassword() {
  lcd.clear();
  if (enteredPassword == storedPassword) {
    // Correct password
    lcd.print("ACCESS GRANTED");
    digitalWrite(relayPin, HIGH); // Turn ON relay (LED on)
    locked = false;
    lcd.setCursor(0, 1);
    lcd.print("Circuit ON");
    // No resetSystem() here to keep the message on screen
  } else {
    // Incorrect password
    lcd.print("WRONG PASSWORD");
    locked = true;
    digitalWrite(relayPin, LOW); // Keep relay OFF (LED off)
    lcd.setCursor(0, 1);
    lcd.print("Try Again");
    delay(2000);
    resetSystem();
  }
}

void resetSystem() {
  enteredPassword = ""; // Clear entered password
  lcd.clear();
  lcd.print("Enter Password:");
}

void displayPassword() {
  lcd.setCursor(0, 1);
  lcd.print("                "); // Clear second row
  lcd.setCursor(0, 1);
  lcd.print(enteredPassword); // Display the entered password
}