typedef struct
{
  uint8_t pin;        // 硬件引脚
  uint32_t tick;      // 消抖计时
  uint8_t lastSta;    // 上一次电平
  uint8_t pressFlag;  // 按下边沿标志：1=本次检测到按下
} Key_t;

typedef enum
{
  LED_ALL_OFF,
  LED_SYNC_SLOW,
  LED_SYNC_FAST,
  LED_ALL_ON
} LedMode_t;

#define DEBOUNCE_MS 20
#define LED1_PIN PC13
#define LED2_PIN PC14

// 实例化4个按键对象
Key_t key1 = {PB11, 0, HIGH, 0};
Key_t key2 = {PB10, 0, HIGH, 0};
Key_t key3 = {PB1,  0, HIGH, 0};
Key_t key4 = {PB0,  0, HIGH, 0};

LedMode_t currentLedMode = LED_ALL_OFF;

// 底层：读取按键电平，传结构体指针
uint8_t Key_Read(Key_t *pKey)
{
  return digitalRead(pKey->pin);
}

// 中层：按键消抖扫描，指针传参
void Key_Scan(Key_t *pKey, uint32_t sysTick)
{
  uint8_t nowLevel = Key_Read(pKey);
  pKey->pressFlag = 0;

  if (nowLevel != pKey->lastSta)
  {
    pKey->tick = sysTick;
  }
  else
  {
    if ((sysTick - pKey->tick) > DEBOUNCE_MS)
    {
      // 下降沿检测：内部上拉，按下变低
      if ((pKey->lastSta == HIGH) && (nowLevel == LOW))
      {
        pKey->pressFlag = 1;
      }
    }
  }
  pKey->lastSta = nowLevel;
}

// 上层：按键事件处理，切换模式，指针传参
void Key_HandleEvent(Key_t *pKey)
{
  if (pKey->pressFlag == 1)
  {
    if (pKey == &key1)
    {
      currentLedMode = LED_SYNC_SLOW;
    }
    else if (pKey == &key2)
    {
      currentLedMode = LED_SYNC_FAST;
    }
    else if (pKey == &key3)
    {
      currentLedMode = LED_ALL_ON;
    }
    else if (pKey == &key4)
    {
      currentLedMode = LED_ALL_OFF;
    }
  }
}

// 双LED运行逻辑
void Led_Run(LedMode_t mode, uint32_t sysTick)
{
  static uint32_t lastTime = 0;
  uint32_t delta = sysTick - lastTime;

  switch (mode)
  {
    case LED_ALL_OFF:
      digitalWrite(LED1_PIN, HIGH);
      digitalWrite(LED2_PIN, HIGH);
      break;

    case LED_SYNC_SLOW:
      if (delta >= 500)
      {
        digitalWrite(LED1_PIN, !digitalRead(LED1_PIN));
        digitalWrite(LED2_PIN, !digitalRead(LED2_PIN));
        lastTime = sysTick;
      }
      break;

    case LED_SYNC_FAST:
      if (delta >= 100)
      {
        digitalWrite(LED1_PIN, !digitalRead(LED1_PIN));
        digitalWrite(LED2_PIN, !digitalRead(LED2_PIN));
        lastTime = sysTick;
      }
      break;

    case LED_ALL_ON:
      digitalWrite(LED1_PIN, LOW);
      digitalWrite(LED2_PIN, LOW);
      break;
    default:
      break;
  }
}

void setup()
{
  pinMode(LED1_PIN, OUTPUT);
  pinMode(LED2_PIN, OUTPUT);
  // 按键内部上拉
  pinMode(key1.pin, INPUT_PULLUP);
  pinMode(key2.pin, INPUT_PULLUP);
  pinMode(key3.pin, INPUT_PULLUP);
  pinMode(key4.pin, INPUT_PULLUP);

  digitalWrite(LED1_PIN, HIGH);
  digitalWrite(LED2_PIN, HIGH);
}

void loop()
{
  uint32_t t = millis();

  Key_Scan(&key1, t);
  Key_HandleEvent(&key1);

  Key_Scan(&key2, t);
  Key_HandleEvent(&key2);

  Key_Scan(&key3, t);
  Key_HandleEvent(&key3);

  Key_Scan(&key4, t);
  Key_HandleEvent(&key4);

  Led_Run(currentLedMode, t);
}