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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &TinyWireM, OLED_RESET);

#define BUTTON_UP 0
#define BUTTON_DOWN 1
#define BUTTON_SELECT 2

int menuIndex = 0;
const char* menuItems[] = {"Start", "Settings", "About", "Exit"};
const int menuLength = sizeof(menuItems) / sizeof(menuItems[0]);

void setup() {
    pinMode(BUTTON_UP, INPUT_PULLUP);
    pinMode(BUTTON_DOWN, INPUT_PULLUP);
    pinMode(BUTTON_SELECT, INPUT_PULLUP);
    
    TinyWireM.begin();
    if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
        for (;;);
    }
    display.clearDisplay();
}

void loop() {
    if (digitalRead(BUTTON_UP) == LOW) {
        menuIndex = (menuIndex - 1 + menuLength) % menuLength;
        delay(200);
    }
    if (digitalRead(BUTTON_DOWN) == LOW) {
        menuIndex = (menuIndex + 1) % menuLength;
        delay(200);
    }
    if (digitalRead(BUTTON_SELECT) == LOW) {
        executeMenuAction(menuIndex);
        delay(200);
    }
    drawMenu();
}

void drawMenu() {
    display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(SSD1306_WHITE);
    for (int i = 0; i < menuLength; i++) {
        if (i == menuIndex) {
            display.setCursor(10, i * 10);
            display.print("> ");
        } else {
            display.setCursor(20, i * 10);
        }
        display.print(menuItems[i]);
    }
    display.display();
}

void executeMenuAction(int index) {
    display.clearDisplay();
    display.setCursor(10, 30);
    display.print("Selected: ");
    display.print(menuItems[index]);
    display.display();
    delay(1000);
}