// +build darwin netbsd freebsd openbsd dragonfly

package internal

import (
	"syscall"
	"time"
)

func AddWrite(p, fd int, on *bool) error {
	if *on {
		return nil
	}
	*on = true
	_, err := syscall.Kevent(p,
		[]syscall.Kevent_t{{Ident: uint64(fd),
			Flags: syscall.EV_ADD, Filter: syscall.EVFILT_WRITE}},
		nil, nil)
	return err
}
func DelWrite(p, fd int, on *bool) error {
	if !*on {
		return nil
	}
	*on = false
	_, err := syscall.Kevent(p,
		[]syscall.Kevent_t{{Ident: uint64(fd),
			Flags: syscall.EV_DELETE, Filter: syscall.EVFILT_WRITE}},
		nil, nil)
	return err
}

func MakePoll() (p int, err error) {
	return syscall.Kqueue()
}
func AddRead(p, fd int) error {
	_, err := syscall.Kevent(p,
		[]syscall.Kevent_t{{Ident: uint64(fd),
			Flags: syscall.EV_ADD, Filter: syscall.EVFILT_READ}},
		nil, nil)
	return err
}
func MakeEvents(n int) interface{} {
	return make([]syscall.Kevent_t, n)
}
func Wait(p int, evs interface{}, timeout time.Duration) (n int, err error) {
	if timeout < 0 {
		timeout = 0
	}
	ts := syscall.NsecToTimespec(int64(timeout))
	return syscall.Kevent(p, nil, evs.([]syscall.Kevent_t), &ts)
}
func GetFD(evs interface{}, i int) int {
	return int(evs.([]syscall.Kevent_t)[i].Ident)
}