#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define widthScreen 128
#define heightScreen 64

#define resetPin -1

const int buttonSatu = 6;
const int buttonDua = 5;
const int buttonEnter = 4;

Adafruit_SSD1306 display(widthScreen, heightScreen, &Wire, resetPin);

int menu = 0;
int subMenu = 0;
bool inSubMenu = false;
unsigned long lastButtonPress = 0;
const unsigned long debounceDelay = 200;

void setup() {
  Serial.begin(9600);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("Oled gagal terkoneksi"));
    for (;;);
  }

  pinMode(buttonSatu, INPUT_PULLUP);
  pinMode(buttonDua, INPUT_PULLUP);
  pinMode(buttonEnter, INPUT_PULLUP);
}

void loop() {
  checkButtons();
  if (inSubMenu) {
    displaySubMenu();
  } else {
    mainMenu();
  }
}

void checkButtons() {
  unsigned long currentMillis = millis();

  if (currentMillis - lastButtonPress >= debounceDelay) {
    byte readButtonSatu = digitalRead(buttonSatu);
    byte readButtonDua = digitalRead(buttonDua);
    byte readButtonEnter = digitalRead(buttonEnter);

    if (readButtonSatu == LOW) {
      if (inSubMenu) {
        inSubMenu = false;
      } else {
        menu++;
      }
      lastButtonPress = currentMillis;
    }

    if (readButtonDua == LOW) {
      if (inSubMenu) {
        inSubMenu = false;
      } else {
        menu++;
      }
      lastButtonPress = currentMillis;
    }

    if (readButtonEnter == LOW) {
      if (!inSubMenu) {
        inSubMenu = true;
        subMenu = menu % 3;
      }
      lastButtonPress = currentMillis;
    }
  }
}

void mainMenu() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0, 2);

  switch (menu % 3) {
    case 0:
      display.println("> Calculator");
      display.println("Contact");
      display.println("Setting");
      break;

    case 1:
      display.println("Calculator");
      display.println("> Contact");
      display.println("Setting");
      break;

    case 2:
      display.println("Calculator");
      display.println("Contact");
      display.println("> Setting");
      break;
  }

  display.display();
}

void displaySubMenu() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0, 2);

  switch (subMenu) {
    case 0:
      display.println("Calculator Menu");
      break;

    case 1:
      display.println("Contact Menu");
      break;

    case 2:
      display.println("Setting Menu");
      break;
  }

  display.display();
}