package auth

/*
#include <utmpx.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>

#include "utmpx_time.h"
*/
import "C"
import (
	"time"
	"unsafe"
)

type UtmpxSession struct {
	ok       bool
	username string
	tty      uint8
}

func AddUtmpx(user string, tty uint8, pid uint32) *UtmpxSession {
	s := &UtmpxSession{username: user, tty: tty}

	cUser := C.CString(user)
	defer C.free(unsafe.Pointer(cUser))

	var ut C.struct_utmpx
	C.memset(unsafe.Pointer(&ut), 0, C.sizeof_struct_utmpx)

	ut.ut_type = C.USER_PROCESS
	ut.ut_pid = C.pid_t(pid)

	n := len(user)
	if n > 32 {
		n = 32
	}
	for i := 0; i < n; i++ {
		ut.ut_user[i] = C.char(user[i])
	}

	ttyCh := byte('0' + tty)
	ut.ut_line[0] = 't'
	ut.ut_line[1] = 't'
	ut.ut_line[2] = 'y'
	ut.ut_line[3] = C.char(ttyCh)
	ut.ut_id[0] = C.char(ttyCh)

	us := time.Now().UnixMicro()
	C.latchd_set_utmpx_time(&ut, C.int64_t(us/1_000_000), C.int32_t(us%1_000_000))

	C.setutxent()
	C.pututxline(&ut)

	s.ok = true
	return s
}

func (s *UtmpxSession) Close() {
	if !s.ok {
		return
	}

	var ut C.struct_utmpx
	C.memset(unsafe.Pointer(&ut), 0, C.sizeof_struct_utmpx)
	ut.ut_type = C.DEAD_PROCESS

	C.setutxent()
	C.pututxline(&ut)
	C.endutxent()

	s.ok = false
}