// OLED Menu Navigation Template for ESP32
// Adapted by S. James Parsons Jr. with ChatGPT refinement

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

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

// ---- Menu State ----
int windowVariable = 1; // top-level menu starts at 1 (e.g., Home menu)

// ---- Menus ----
const char* mainMenu[] = {"Polar Angle", "Kinetics", "Settings", "Credits", "QR Code"};
const char* settingsMenu[] = {"Light Intensity", "Temperature Range"};

// ---- Function Prototypes ----
void showMenu(const char* title, const char* items[], int count, int selected);
void handleMenu(int window);
int getCurrentSelection(int value);
void navigateUp();
void navigateDown(int maxItems);
void selectItem();
void goBack();

void setup() {
  Serial.begin(115200); // ESP32 default baud rate

  // Initialize I2C manually for ESP32 (optional if using default SDA/SCL)
  Wire.begin(21, 22); // SDA = GPIO21, SCL = GPIO22 (standard ESP32 I2C pins)

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    while (true);
  }

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.cp437(true);
  display.display();
}

void loop() {
  handleMenu(windowVariable);

  // TEMPORARY: Emulate button presses for testing
  if (Serial.available()) {
    char input = Serial.read();
    switch (input) {
      case 'u': navigateUp(); break;
      case 'd': navigateDown(5); break; // Update maxItems per menu
      case 's': selectItem(); break;
      case 'b': goBack(); break;
    }
  }

  delay(200);
}

// ---- Menu Rendering ----
void showMenu(const char* title, const char* items[], int count, int selected) {
  display.clearDisplay();
  display.setCursor(0, 0);
  display.setTextColor(BLACK, WHITE);
  display.println(title);
  display.setTextColor(WHITE);

  for (int i = 0; i < count; i++) {
    display.setCursor(20, 10 + i * 10);
    display.println(items[i]);
  }

  display.setCursor(10, 10 + selected * 10);
  display.write(0x3E); // > arrow
  display.display();
}

// ---- Menu Handling ----
void handleMenu(int window) {
  int root = window;
  while (root >= 10) root /= 10;
  int selection = getCurrentSelection(window);

  switch (root) {
    case 1:
      showMenu("Home", mainMenu, sizeof(mainMenu) / sizeof(char*), selection);
      break;
    case 3:
      showMenu("Settings", settingsMenu, sizeof(settingsMenu) / sizeof(char*), selection);
      break;
    case 10:
      display.clearDisplay();
      display.setCursor(0, 0);
      display.println("Polar Angle Tool");
      display.display();
      break;
    // Add more cases for tools/screens as needed
  }
}

// ---- Navigation Helpers ----
int getCurrentSelection(int value) {
  return value % 10;
}

void navigateUp() {
  int sel = getCurrentSelection(windowVariable);
  if (sel > 0) windowVariable--;
}

void navigateDown(int maxItems) {
  int sel = getCurrentSelection(windowVariable);
  if (sel < maxItems - 1) windowVariable++;
}

void selectItem() {
  windowVariable *= 10;
}

void goBack() {
  windowVariable /= 10;
}