#include <LiquidCrystal_I2C.h>  // Library for I2C LCD
#include <RotaryEncoder.h>      // Library for Rotary Encoder

// LCD I2C setup (address: 0x27, columns: 16, rows: 4)
LiquidCrystal_I2C lcd(0x27, 16, 4);

// Rotary Encoder Pins
#define CLK_PIN 2
#define DT_PIN 3
#define SW_PIN 4

// Rotary Encoder Initialization
RotaryEncoder encoder(CLK_PIN, DT_PIN);

// Menu Variables
int menuLevel = 0;
int menuIndex = 0;
const char *mainMenu[] = {"Univ Batna 1", "Univ Batna 2"};
const char *faculties[] = {"Faculty 1", "Faculty 2","Faculty 3","Faculty 4"};
const char *departments[] = {"Dept 1", "Dept 2","Dept 3","Dept 4"};
const char *specialties[] = {"Specialty 1", "Specialty 2","Specialty 3","Specialty 4"};

int studentCount = 100;  // Default student count

void setup() {
  pinMode(SW_PIN, INPUT_PULLUP);  // Rotary encoder button setup
  lcd.init();
  lcd.backlight();
  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("Welcome!");
  delay(2000);
  displayMenu();
}

void loop() {
  static int lastPosition = 0;
  encoder.tick();

  // Check rotary encoder movement
  int newPosition = encoder.getPosition();
  if (newPosition != lastPosition) {
    if (newPosition > lastPosition) {
      menuIndex++;
    } else {
      menuIndex--;
    }
    lastPosition = newPosition;

    // Wrap around menu index
    if (menuLevel == 0) {
      if (menuIndex >= 2) menuIndex = 0;
      if (menuIndex < 0) menuIndex = 1;
    }
    displayMenu();
  }

  // Check button press
  if (digitalRead(SW_PIN) == LOW) {
    handleButtonPress();
    delay(300);  // Debounce delay
  }
}

// Function to display the menu based on the current level
void displayMenu() {
  lcd.clear();
  lcd.setCursor(0, 0);

  switch (menuLevel) {
    case 0:  // Main Menu
      lcd.print(mainMenu[menuIndex]);
      break;
    case 1:  // Faculties
      lcd.print("Faculties:");
      lcd.setCursor(0, 1);
      lcd.print(faculties[menuIndex]);
      break;
    case 2:  // Departments
      lcd.print("Departments:");
      lcd.setCursor(0, 1);
      lcd.print(departments[menuIndex]);
      break;
    case 3:  // Specialties
      lcd.print("Specialties:");
      lcd.setCursor(0, 1);
      lcd.print(specialties[menuIndex]);
      break;
    case 4:  // Student Count
      lcd.print("Students Count:");
      lcd.setCursor(0, 1);
      lcd.print(studentCount);
      break;
  }
}

// Function to handle button press
void handleButtonPress() {
  if (menuLevel < 4) {
    menuLevel++;
    menuIndex = 0;  // Reset menu index for sub-menus
  } else {
    // Adjust student count
    studentCount += (menuIndex > 0) ? 1 : -1;
    if (studentCount < 0) studentCount = 0;
  }
  displayMenu();
}