#include <Adafruit_NeoPixel.h>

#define slide 15        //滑桿
#define sw1 25          //指撥紅色
#define sw2 26          //指撥綠色
#define sw3 27          //指撥藍色
#define sw4 14          //彩虹
#define LED_PIN     23      //接WS2812燈條的DIN腳
#define NUM_LEDS    16      //LED數量
#define BRIGHTNESS  255     //亮度255
#define LED_TYPE    WS2812  //類型WS2812

Adafruit_NeoPixel strip(NUM_LEDS, LED_PIN, NEO_GRB + NEO_KHZ800);

void setup() {
  Serial.begin(115200);
  pinMode(sw1, INPUT_PULLUP); //開關(內部提升電阻)
  pinMode(sw2, INPUT_PULLUP);
  pinMode(sw3, INPUT_PULLUP);
  pinMode(sw4, INPUT_PULLUP);
}
//=================================================================
void loop() { 
  static int prevValue = -1;  // 儲存上一個 Value，避免重複更新
  int val = analogRead(slide);  // 讀取滑桿值 0~4095
  int Value = map(val, 0, 4095, 0, 16);  // 對應到 16 個 LED 的數量
  
  // 只要SW4 被按下，觸發彩虹效果
  if (!digitalRead(sw4)) {  // 啟動彩虹模式
    rainbowCycle();      // 執行彩虹效果
    return;                // 不繼續執行其他燈條更新
  }
  // 當滑桿值變化或指撥開關被按下時更新燈條
  if (Value != prevValue || !digitalRead(sw1) || !digitalRead(sw2) ||\
   !digitalRead(sw3)) {
    
    for (int i = Value; i < 16; i++) {  // 清除不需要亮的像素
      strip.setPixelColor(i, 0, 0, 0);
    }
    
    for (int i = 0; i < Value; i++) {   // 指撥改顏色
      uint8_t red = 0, green = 0, blue = 0;
      if (!digitalRead(sw1)) red = 255;
      if (!digitalRead(sw2)) green = 255;
      if (!digitalRead(sw3)) blue = 255;
      strip.setPixelColor(i, red, green, blue);
    }
    strip.show();
    prevValue = Value;  // 更新上一個 Value
  }
  delay(10);  // 短暫延遲避免高頻處理
}

//=================================================================
void rainbowCycle() {
 for (int i = 0; i < 256 * 5; i++) {
  for (int j = 0; j < strip.numPixels(); j++) {
   strip.setPixelColor(j, Wheel(((j * 255) / strip.numPixels()) + i % 256));            
  }
  strip.show();
 }
}
int Wheel(byte WheelPos) {
  if (WheelPos < 85) {
    return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  } else if (WheelPos < 170) {
    WheelPos -= 85;
    return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  } else {
    WheelPos -= 170;
    return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
  }
}