#include <Wire.h>              // I2C communication library
#include <Adafruit_SSD1306.h>  // Adafruit SSD1327 library for OLED
#include <ESP32RotaryEncoder.h> // ESP32RotaryEncoder library by Matthew Clark

// OLED display configuration (SSD1327 128x128 via I2C on ESP32 default pins)
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1); // -1 for no reset pin

// Rotary encoder pin definitions for ESP32
#define ENCODER_PIN_A 12       // Encoder pin A (CLK)
#define ENCODER_PIN_B 14       // Encoder pin B (DT)
#define BUTTON_PIN 27          // Encoder button pin (SW)

// Initialize the rotary encoder object
RotaryEncoder encoder(ENCODER_PIN_A, ENCODER_PIN_B, BUTTON_PIN, -1);

// Menu items and variables
const char* menuItems[] = {"Start", "Settings", "About", "Exit"};
const int numItems = 4;        // Number of menu items
volatile int menuIndex = 0;    // Currently selected menu item index (volatile for interrupt)
volatile bool buttonPressed = false; // Flag for button press

// Declare callback functions at the top
//void onEncoderTurned(int newCount); // Declaration for rotation callback
//void onButtonPressed(unsigned long timestamp); // Declaration for button press callback with timestamp

// Draw menu function
void drawMenu() {
  display.clearDisplay();
  display.setTextSize(2); // Text size 2 (16 pixels high)
  for (int i = 0; i < numItems; i++) {
    if (i == menuIndex) {
      // Highlight selected item with white background and black text
      display.fillRect(0, i * 16, SCREEN_WIDTH, 16, WHITE);
      display.setTextColor(BLACK);
    } else {
      display.setTextColor(WHITE);
    }
    display.setCursor(0, i * 16);
    display.println(menuItems[i]);
  }
  display.display(); // Update the display
}

// Define callback functions
void onEncoderTurned(int newCount) {
  menuIndex = newCount; // Update menuIndex with the new count
}

void onButtonPressed(unsigned long timestamp) {
  buttonPressed = true; // Set flag to handle in loop (timestamp ignored)
}

void setup() {
  // Start serial communication for debugging
  Serial.begin(115200);

  // Initialize the OLED display
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // I2C addressadjust to 0x3C if needed
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); // Loop forever if display fails
  }
  display.clearDisplay();
  display.display();

  // Configure the rotary encoder
  encoder.setEncoderType( EncoderType::HAS_PULLUP );
  encoder.setBoundaries(0, numItems - 1); // Set min/max values (0 to 3)
  encoder.onTurned(onEncoderTurned);      // Set rotation callback
  encoder.onPressed(onButtonPressed);     // Set button press callback
  encoder.begin();                        // Initialize encoder with interrupts
  Serial.println("ESP32 Menu System Started");
}

void loop() {
  // Draw the menu (menuIndex updated via callback or reset)
  drawMenu();

  // Handle button press (set by callback)
  if (buttonPressed) {
    display.clearDisplay();
    display.setTextSize(2);
    display.setTextColor(WHITE);
    display.setCursor(0, 0);
    switch (menuIndex) {
      case 0: // Start
        display.println("Starting...");
        break;
      case 1: // Settings
        display.println("Settings:");
        break;
      case 2: // About
        display.println("About:");
        break;
      case 3: // Exit
        display.println("Exiting...");
        break;
    }
    display.display();
    delay(2000); // Show message for 2 seconds
    menuIndex = 0; // Reset to first page (Start)
    buttonPressed = false; // Reset flag
  }
}