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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

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

#define BUTTON_UP 2
#define BUTTON_DOWN 3
#define BUTTON_SELECT 4

enum Menu {
  TEMPERATURE,
  VOLUME,
  LIGHTS,
  BATTERY,
  DIFFICULTY
};

Menu currentMenu = TEMPERATURE;
int selectedItem = 0;
int lightsState[4] = {0, 0, 0, 0}; // 0 - off, 1 - on
int volumeLevel = 50; // Initial volume level
int batteryPercentage = 76; // Example battery percentage
int batteryMode = 0; // 0 for battery save mode, 1 for performance mode

unsigned long debounceDelay = 50;
unsigned long lastDebounceTime = 0;
bool buttonHeld = false;
bool inSubMenu = false;

void displayTemperatureScreen() {
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(0,0);
  display.println("Temperature:");
  float temperature = random(200, 300) / 10.0; // Simulated temperature reading (20.0 - 30.0)
  display.print(temperature);
  display.println("C");
  display.display();
}

void displayVolumeScreen() {
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(0,0);
  display.println("Volume:");
  display.print(volumeLevel);
  display.println("%");
  display.display();
}

void displayLightsScreen() {
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(0,0);
  display.println("Lights:");
  for (int i = 0; i < 4; i++) {
    display.print("Light ");
    display.print(char('A' + i));
    display.print(": ");
    display.println(lightsState[i] ? "On" : "Off");
  }
  display.display();
}

void displayBatteryScreen() {
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(0,0);
  display.println("Battery:");
  display.print(batteryPercentage);
  display.println("%");

  display.println("Battery Mode:");
  if (batteryMode == 0) {
    display.setTextColor(SSD1306_BLACK, SSD1306_WHITE); // Highlight the active mode
    display.println("Battery Save");
    display.setTextColor(SSD1306_WHITE);
    display.println("Performance");
  } else {
    display.println("Battery Save");
    display.setTextColor(SSD1306_BLACK, SSD1306_WHITE); // Highlight the active mode
    display.println("Performance");
    display.setTextColor(SSD1306_WHITE);
  }
  display.display();
}

void displayDifficultyScreen() {
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(0,0);
  display.println("Difficulty:");
  for (int i = 0; i < 3; i++) {
    if (i == selectedItem) {
      display.setTextColor(SSD1306_BLACK, SSD1306_WHITE); // Highlight the selected difficulty
    } else {
      display.setTextColor(SSD1306_WHITE);
    }
    switch (i) {
      case 0:
        display.println("Easy");
        break;
      case 1:
        display.println("Normal");
        break;
      case 2:
        display.println("Hard");
        break;
    }
  }
  display.display();
}

void displayMenu(int start) {
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(0, 0);
  display.println("Menu:");
  for (int i = start; i < start + 3; i++) {
    if (i == selectedItem) {
      display.setTextColor(SSD1306_BLACK, SSD1306_WHITE); // Highlight the selected item
    } else {
      display.setTextColor(SSD1306_WHITE);
    }
    switch (i) {
      case TEMPERATURE:
        display.println("Temperature");
        break;
      case VOLUME:
        display.println("Volume");
        break;
      case LIGHTS:
        display.println("Lights");
        break;
      case BATTERY:
        display.println("Battery");
        break;
      case DIFFICULTY:
        display.println("Difficulty");
        break;
    }
  }
  display.display();
}

void setup() {
  Wire.begin();
  Serial.begin(9600);
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;);
  }
  
  pinMode(BUTTON_UP, INPUT_PULLUP);
  pinMode(BUTTON_DOWN, INPUT_PULLUP);
  pinMode(BUTTON_SELECT, INPUT_PULLUP);
  
  displayMenu(0); // Display the initial menu
}

void loop() {
  int upState = digitalRead(BUTTON_UP);
  int downState = digitalRead(BUTTON_DOWN);
  int selectState = digitalRead(BUTTON_SELECT);

  if (upState == LOW && !inSubMenu) {
    selectedItem = max(0, selectedItem - 1);
    displayMenu(selectedItem > 1 ? selectedItem - 1 : 0); // Update the menu display
    delay(250); // Button delay to prevent rapid changes
  }

  if (downState == LOW && !inSubMenu) {
    selectedItem = min(4, selectedItem + 1);
    displayMenu(selectedItem > 1 ? selectedItem - 1 : 0); // Update the menu display
    delay(250); // Button delay to prevent rapid changes
  }

  if (selectState == LOW) {
    if (!inSubMenu) {
      switch (selectedItem) {
        case TEMPERATURE:
          displayTemperatureScreen();
          break;
        case VOLUME:
          displayVolumeScreen();
          inSubMenu = true;
          break;
        case LIGHTS:
          displayLightsScreen();
          break;
        case BATTERY:
          displayBatteryScreen();
          break;
        case DIFFICULTY:
          displayDifficultyScreen();
          break;
      }
      delay(500); // Button delay to prevent rapid changes
    } else { // Inside a submenu
      if (selectedItem == VOLUME) {
        if (upState == LOW) {
          volumeLevel = min(100, volumeLevel + 1);
          displayVolumeScreen();
          delay(250);
        }
        if (downState == LOW) {
          volumeLevel = max(0, volumeLevel - 1);
          displayVolumeScreen();
          delay(250);
        }
      }
    }
  } else {
    inSubMenu = false; // Reset submenu state if SELECT button is released
  }
}