const int buttonPin = 2;   // 按钮连接到 D2
const int motor1 = 9;      // 电机驱动 IN1
const int motor2 = 10;     // 电机驱动 IN2
const int motor3 = 11;     // 电机驱动 IN3
const int motor4 = 12;     // 电机驱动 IN4

int buttonState = 0;
int lastButtonState = LOW;
int fanSpeed = 0;         // 0: 关闭, 1: 低速, 2: 中速, 3: 高速
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;

void setup() {
    pinMode(buttonPin, INPUT_PULLUP);
    pinMode(motor1, OUTPUT);
    pinMode(motor2, OUTPUT);
    pinMode(motor3, OUTPUT);
    pinMode(motor4, OUTPUT);
}

void loop() {
    int reading = digitalRead(buttonPin);

    // 防抖处理
    if (reading != lastButtonState) {
        lastDebounceTime = millis();
    }

    if ((millis() - lastDebounceTime) > debounceDelay) {
        if (reading == LOW) {
            fanSpeed++;
            if (fanSpeed > 3) fanSpeed = 0;  // 超过 3 级别则归零
        }
    }
    
    lastButtonState = reading;

    // 控制风扇转速
    switch (fanSpeed) {
        case 0:  // 关闭
            stopMotor();
            break;
        case 1:  // 低速
            runMotor(100);
            break;
        case 2:  // 中速
            runMotor(150);
            break;
        case 3:  // 高速
            runMotor(255);
            break;
    }
}

// 运行电机
void runMotor(int speed) {
    analogWrite(motor1, speed);
    analogWrite(motor2, 0);
    analogWrite(motor3, speed);
    analogWrite(motor4, 0);
}

// 停止电机
void stopMotor() {
    analogWrite(motor1, 0);
    analogWrite(motor2, 0);
    analogWrite(motor3, 0);
    analogWrite(motor4, 0);
}