const int ledControlPin = 9;  // LED控制引脚
const int buttonPin = 2;      // 按钮输入引脚
const int debounceTime = 5;   // 消抖时间
const int longPressThreshold = 500;  // 长按阈值
float ledIntensity = 0;       // LED亮度
bool buttonStatus = HIGH;     // 按钮状态
int pressDuration = 0;        // 按钮被按下的持续时间
int dimDirection = 1;         // 调光方向, 1为增加亮度, -1为减少亮度
bool isLongPressed = false;  
void setup() {
  pinMode(ledControlPin, OUTPUT); 
  pinMode(buttonPin, INPUT_PULLUP);  
}

void loop() {
  readButtonState();  // 读取按钮状态
  
  if (buttonStatus == LOW) {  // 如果按钮被按下
    handleButtonPress();
  } else {
    resetStates();  // 当按钮释放时重置状态
  }
}

void readButtonState() {
  buttonStatus = digitalRead(buttonPin);
}

void handleButtonPress() {
  while (buttonStatus == LOW) {
    pressDuration += debounceTime;
    delay(debounceTime);
    checkForLongPress();
    adjustBrightness();
    buttonStatus = digitalRead(buttonPin);
  }
  
  if (pressDuration > debounceTime && pressDuration < longPressThreshold) {
    toggleLED();
  }
}

void checkForLongPress() {
  if (pressDuration >= longPressThreshold && !isLongPressed) {
    determineDimDirection();
    isLongPressed = true;
  }
}

void determineDimDirection() {
  if (ledIntensity <= 0) {
    dimDirection = 1;
  } else if (ledIntensity >= 255) {
    dimDirection = -1;
  } else {
    dimDirection *= -1;
  }
}

void adjustBrightness() {
  if (isLongPressed) {
    ledIntensity += 0.5 * dimDirection;
    constrainBrightness();
    analogWrite(ledControlPin, ledIntensity);
    Serial.println(ledIntensity);
  }
}

void toggleLED() {
  ledIntensity = ledIntensity > 0 ? 0 : 255;
  analogWrite(ledControlPin, ledIntensity);
  Serial.println(ledIntensity);
}

void resetStates() {
  pressDuration = 0;
  isLongPressed = false;
}

void constrainBrightness() {
  ledIntensity = max(0, min(ledIntensity, 255));
}