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

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

#define BUTTON_UP_PIN 13
#define BUTTON_DOWN_PIN 4
#define BUTTON_SELECT_PIN 5

// Define menu options
#define MENU_SIZE 2
const int menuValues[MENU_SIZE] = {120, 60}; // Voltage values in volts
const char* menuLabels[MENU_SIZE] = {"120V", "60V"};

int selectedValueIndex = 0; // Index of the currently selected value
int selectedVoltage = 0;

void setup() {
  Serial.begin(115200);
  pinMode(BUTTON_UP_PIN, INPUT_PULLUP);
  pinMode(BUTTON_DOWN_PIN, INPUT_PULLUP);
  pinMode(BUTTON_SELECT_PIN, INPUT_PULLUP);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }
  delay(500);
  display.clearDisplay(); // Clear the display once during setup
  display.setTextColor(WHITE);
}

void loop() {
  // Clear display before drawing each menu
  display.clearDisplay();

  // Display menu options and current selected value
  display.setTextSize(2);
  display.setCursor(0, 0);
  for (int i = 0; i < MENU_SIZE; ++i) {
    display.print("  ");
    if (i == selectedValueIndex) {
      display.print("> "); // Arrow indicating current selection
      display.setTextColor(WHITE, BLACK); // Invert color for the selected item
    } else {
      display.print("  ");
      display.setTextColor(WHITE);
    }
    display.print(menuLabels[i]);
    display.println();
  }

  // Display currently set value at the bottom center
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(SCREEN_WIDTH / 4, SCREEN_HEIGHT - 10);
  display.print("Selected: ");
  display.print(selectedVoltage);
  display.print("V");

  display.display();

  // Handle button presses
  if (digitalRead(BUTTON_UP_PIN) == LOW) {
    selectedValueIndex = (selectedValueIndex + 1) % MENU_SIZE; // Move to the next value
    delay(200); // Button debounce delay
  }
  if (digitalRead(BUTTON_DOWN_PIN) == LOW) {
    selectedValueIndex = (selectedValueIndex + MENU_SIZE - 1) % MENU_SIZE; // Move to the previous value
    delay(200); // Button debounce delay
  }
  if (digitalRead(BUTTON_SELECT_PIN) == LOW) {
    // Perform action based on the selected value
    int selectedValue = menuValues[selectedValueIndex];
    // Do something with the selected value (e.g., save it to a variable)
    Serial.print("Selected value: ");
    Serial.println(selectedValue);
    selectedVoltage = selectedValue;
    delay(200); // Button debounce delay
  }
}