如何在 Go 中实现全局热键？

const (
    ModAlt = 1 << iota
    ModCtrl
    ModShift
    ModWin
)

type Hotkey struct {
    Id        int
    Modifiers int
    KeyCode   int
}

func main() {
    user32 := syscall.MustLoadDLL("user32")
    reghotkey := user32.MustFindProc("RegisterHotKey")
    keys := map[int16]*Hotkey{
        1: &Hotkey{1, ModAlt + ModCtrl, 'O'},
        2: &Hotkey{2, ModAlt + ModShift, 'M'},
        3: &Hotkey{3, ModAlt + ModCtrl, 'X'},
    }
    for _, v := range keys {
        r1, _, _ := reghotkey.Call(0, uintptr(v.Id), uintptr(v.Modifiers), uintptr(v.KeyCode))
        if r1 == 1 {
            fmt.Println("Registered", v)
        } else {
            fmt.Println("Failed to register", v)
        }
    }
    for {
        var msg = &MSG{}
        peekmsg := user32.MustFindProc("PeekMessageW")
        peekmsg.Call(uintptr(unsafe.Pointer(msg)), 0, 0, 0, 1)
        if id := msg.WPARAM; id != 0 {
            fmt.Println("Hotkey pressed:", keys[id])
            if id == 3 {
                fmt.Println("CTRL+ALT+X pressed, goodbye...")
                return
            }
        }
        time.Sleep(time.Millisecond * 50)
    }
}