// Copyright 2017 Joshua J Baker. All rights reserved.
// Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file.

package internal

import (
	"syscall"
	"time"
)

func AddRead(p, fd int, readon, writeon *bool) error {
	if readon != nil {
		if *readon {
			return nil
		}
		*readon = true
	}
	if writeon == nil || !*writeon {
		return syscall.EpollCtl(p, syscall.EPOLL_CTL_ADD, fd,
			&syscall.EpollEvent{Fd: int32(fd),
				Events: syscall.EPOLLIN,
			})
	}
	return syscall.EpollCtl(p, syscall.EPOLL_CTL_MOD, fd,
		&syscall.EpollEvent{Fd: int32(fd),
			Events: syscall.EPOLLIN | syscall.EPOLLOUT,
		})
}
func DelRead(p, fd int, readon, writeon *bool) error {
	if readon != nil {
		if !*readon {
			return nil
		}
		*readon = false
	}
	if writeon == nil || !*writeon {
		return syscall.EpollCtl(p, syscall.EPOLL_CTL_DEL, fd,
			&syscall.EpollEvent{Fd: int32(fd),
				Events: syscall.EPOLLIN,
			})
	}
	return syscall.EpollCtl(p, syscall.EPOLL_CTL_MOD, fd,
		&syscall.EpollEvent{Fd: int32(fd),
			Events: syscall.EPOLLOUT,
		})
}

func AddWrite(p, fd int, readon, writeon *bool) error {
	if writeon != nil {
		if *writeon {
			return nil
		}
		*writeon = true
	}
	if readon == nil || !*readon {
		return syscall.EpollCtl(p, syscall.EPOLL_CTL_ADD, fd,
			&syscall.EpollEvent{Fd: int32(fd),
				Events: syscall.EPOLLOUT,
			})
	}
	return syscall.EpollCtl(p, syscall.EPOLL_CTL_MOD, fd,
		&syscall.EpollEvent{Fd: int32(fd),
			Events: syscall.EPOLLIN | syscall.EPOLLOUT,
		})
}
func DelWrite(p, fd int, readon, writeon *bool) error {
	if writeon != nil {
		if !*writeon {
			return nil
		}
		*writeon = false
	}
	if readon == nil || !*readon {
		return syscall.EpollCtl(p, syscall.EPOLL_CTL_DEL, fd,
			&syscall.EpollEvent{Fd: int32(fd),
				Events: syscall.EPOLLOUT,
			})
	}
	return syscall.EpollCtl(p, syscall.EPOLL_CTL_MOD, fd,
		&syscall.EpollEvent{Fd: int32(fd),
			Events: syscall.EPOLLIN,
		})
}
func MakePoll() (p int, err error) {
	return syscall.EpollCreate1(0)
}
func MakeEvents(n int) interface{} {
	return make([]syscall.EpollEvent, n)
}
func Wait(p int, evs interface{}, timeout time.Duration) (n int, err error) {
	if timeout < 0 {
		timeout = 0
	}
	ts := int(timeout / time.Millisecond)
	return syscall.EpollWait(p, evs.([]syscall.EpollEvent), ts)
}
func GetFD(evs interface{}, i int) int {
	return int(evs.([]syscall.EpollEvent)[i].Fd)
}