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

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

// NeoPixel 設定
#define LED_PIN     6
#define NUM_PIXELS  8
Adafruit_NeoPixel strip(NUM_PIXELS, LED_PIN, NEO_GRB + NEO_KHZ800);

// 按鈕定義
#define BT_UP     3
#define BT_DOWN   5
#define BT_OK     10
#define BT_BACK   11

// 選單內容（4 項）
const int menuSize = 4;
const char* menuItems[menuSize] = {
  "Red Breathing",
  "Purple Runner",
  "Random Blink",
  "Step Lights"
};

int menuIndex = 0;
bool inSubMenu = false;
int stepIndex = 0;

// 防彈跳
unsigned long lastDebounce = 0;
const unsigned long debounceDelay = 150;

void setup() {
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(20, 20);
  display.println("RGB Menu System");
  display.setCursor(35, 35);
  display.println("by Student");
  display.display();
  delay(3000);

  pinMode(BT_UP, INPUT_PULLUP);
  pinMode(BT_DOWN, INPUT_PULLUP);
  pinMode(BT_OK, INPUT_PULLUP);
  pinMode(BT_BACK, INPUT_PULLUP);

  strip.begin();
  strip.show();
}

void loop() {
  if (!inSubMenu) {
    drawMenu();
    handleMenuInput();
  } else {
    handleSubMenu(menuIndex);
  }
}

// 顯示選單介面
void drawMenu() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);

  display.setCursor(40, 0);
  display.println("MENU");
  display.drawLine(0, 10, 127, 10, WHITE);

  for (int i = 0; i < menuSize; i++) {
    display.setCursor(0, 12 + i * 12);
    if (i == menuIndex) {
      display.print("> ");
    } else {
      display.print("  ");
    }
    display.println(menuItems[i]);
  }

  display.display();
}

// 處理選單按鈕輸入
void handleMenuInput() {
  if (millis() - lastDebounce > debounceDelay) {
    if (digitalRead(BT_UP) == LOW) {
      menuIndex = (menuIndex - 1 + menuSize) % menuSize;
      lastDebounce = millis();
    }
    if (digitalRead(BT_DOWN) == LOW) {
      menuIndex = (menuIndex + 1) % menuSize;
      lastDebounce = millis();
    }
    if (digitalRead(BT_OK) == LOW) {
      inSubMenu = true;
      strip.clear(); strip.show();
      lastDebounce = millis();
    }
  }
}

// 處理各子選單功能
void handleSubMenu(int index) {
  if (digitalRead(BT_BACK) == LOW && millis() - lastDebounce > debounceDelay) {
    inSubMenu = false;
    strip.clear(); strip.show();
    lastDebounce = millis();
    return;
  }

  switch (index) {
    case 0: redBreathing(); break;
    case 1: purpleRunner(); break;
    case 2: randomBlink(); break;
    case 3: stepLighting(); break;
  }
}

// 模式 1：紅色呼吸燈
void redBreathing() {
  static int brightness = 0;
  static int fadeAmount = 5;
  for (int i = 0; i < NUM_PIXELS; i++) {
    strip.setPixelColor(i, strip.Color(brightness, 0, 0));
  }
  strip.show();
  brightness += fadeAmount;
  if (brightness <= 0 || brightness >= 255) fadeAmount = -fadeAmount;
  delay(30);
}

// 模式 2：紫色跑馬燈
void purpleRunner() {
  static int position = 0;

  strip.clear();
  for (int i = 0; i < 3; i++) {
    int pixel = (position - i + NUM_PIXELS) % NUM_PIXELS;
    int brightness = 255 - i * 80;
    strip.setPixelColor(pixel, strip.Color(brightness, 0, brightness)); // 紫色
  }
  strip.show();
  position = (position + 1) % NUM_PIXELS;
  delay(100);
}

// 模式 3：隨機閃爍
void randomBlink() {
  int i = random(NUM_PIXELS);
  strip.setPixelColor(i, strip.Color(random(255), random(255), random(255)));
  strip.show();
  delay(100);
  strip.setPixelColor(i, 0);
  strip.show();
}

// 模式 4：段數點亮
void stepLighting() {
  if (digitalRead(BT_OK) == LOW && millis() - lastDebounce > debounceDelay) {
    if (stepIndex < NUM_PIXELS) {
      strip.setPixelColor(stepIndex, strip.Color(0, 0, 255));
      strip.show();
      stepIndex++;
    } else {
      stepIndex = 0;
      strip.clear(); strip.show();
    }
    lastDebounce = millis();
  }
}