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

const int totalStudents = 10;
char studentNames[10][20] = {"Hazim", "Haiqal", "Husni", "Hadif", "Irfan", "Iskandar", "Maisarah", "Ariana", "Amirah", "Damia"};
bool attendanceStatus[10] = {false};

const byte ROWS = 4;
const byte COLS = 4;

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

byte rowPins[ROWS] = {19, 18, 5, 17};
byte colPins[COLS] = {16, 4, 0, 2};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);
LiquidCrystal_I2C lcd(0x27, 16, 2); // Change 0x27 to your I2C address if different

const int buttonPin = 13;  // Pin connected to the push button
const int buzzerPin = 12;  // Pin connected to the buzzer

bool keypadEnabled = true; // Flag to check if keypad is enabled
int currentStudent = 0;
bool lastButtonState = HIGH; // Previous state of the button
unsigned long lastDebounceTime = 0; // Last time the button state was toggled
unsigned long debounceDelay = 50; // Debounce time in milliseconds

void setup() {
  pinMode(buttonPin, INPUT_PULLUP); // Enable internal pull-up resistor
  pinMode(buzzerPin, OUTPUT); // Set the buzzer pin as output
  lcd.begin(16, 2);
  lcd.init(); // Initialize the LCD
  lcd.backlight(); // Ensure the backlight is turned on
  lcd.print("Attendance System");
  delay(2000);
  lcd.clear();
}

void loop() {
  // Read the state of the button
  bool reading = digitalRead(buttonPin);

  // Check if the button state has changed
  if (reading != lastButtonState) {
    lastDebounceTime = millis(); // Reset the debounce timer
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    // If the button state has stabilized and is LOW, toggle the keypad state
    if (reading == LOW) {
      keypadEnabled = !keypadEnabled;
      lastDebounceTime = millis(); // Reset debounce timer to avoid multiple toggles
    }
  }

  lastButtonState = reading;

  if (keypadEnabled) {
    char key = keypad.getKey();

    if (key) {
      switch (key) {
        case '#':
          markPresent();
          break;
        case 'A':
          displayPresentCount();
          break;
        case 'B':
          displayAbsentCount();
          break;
        case 'C':
          displayPresentNames();
          break;
        case 'D':
          displayAbsentNames();
          break;
        case '*':
          displayNextStudent();
          break;
      }
    }
  } else {
    lcd.clear();
    lcd.print("Keypad Disabled");
  }
}

void markPresent() {
  attendanceStatus[currentStudent] = true;  // mark as present
  lcd.clear();
  lcd.print(studentNames[currentStudent]);
  lcd.setCursor(0, 1);
  lcd.print("Present!");
  digitalWrite(buzzerPin, HIGH); // Turn on the buzzer
  delay(1000); // Keep the buzzer on for 1 second
  digitalWrite(buzzerPin, LOW); // Turn off the buzzer
  lcd.clear();
  currentStudent++;
  if (currentStudent >= totalStudents) {
    currentStudent = 0;  // Reset to the first student
  }
}

void displayPresentCount() {
  int presentCount = 0;
  for (int i = 0; i < totalStudents; i++) {
    if (attendanceStatus[i]) {
      presentCount++;
    }
  }
  lcd.clear();
  lcd.print("Present: ");
  lcd.print(presentCount);
  delay(2000);
  lcd.clear();
}

void displayAbsentCount() {
  int absentCount = totalStudents - currentStudent;
  lcd.clear();
  lcd.print("Absent: ");
  lcd.print(absentCount);
  delay(2000);
  lcd.clear();
}

void displayPresentNames() {
  lcd.clear();
  lcd.print("Present Students:");
  delay(1000);
  lcd.clear();
  for (int i = 0; i < totalStudents; i++) {
    if (attendanceStatus[i]) {
      lcd.clear();
      lcd.print(studentNames[i]);
      delay(1000);
      lcd.clear();
    }
  }
  lcd.clear();
}

void displayAbsentNames() {
  lcd.clear();
  lcd.print("Absent Students:");
  delay(1000);
  lcd.clear();
  for (int i = 0; i < totalStudents; i++) {
    if (!attendanceStatus[i]) {
      lcd.clear();
      lcd.print(studentNames[i]);
      delay(1000);
      lcd.clear();
    }
  }
  lcd.clear();
}

void displayNextStudent() {
  lcd.clear();
  lcd.print(studentNames[currentStudent]);
  delay(1000);
  lcd.clear();
  currentStudent++;
  if (currentStudent >= totalStudents) {
    currentStudent = 0;  // Reset to the first student
  }
}