// udpobfs -- simple point-to-point UDP obfuscation proxy
// Copyright (C) 2023-2024 Sergey Matveev <stargrave@stargrave.org>
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 3 of the License.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package udpobfs

import (
	"io"
	"log"
	"net"
	"time"
)

const BufLen = 1 << 14

var (
	PingDuration     = 10 * time.Second
	LifetimeDuration = time.Minute
)

func MustWrite(w io.Writer, data []byte) {
	if n, err := w.Write(data); err != nil || n != len(data) {
		log.Fatal("non full write")
	}
}

func Incr(buf []byte) (overflow bool) {
	for i := len(buf) - 1; i >= 0; i-- {
		buf[i]++
		if buf[i] != 0 {
			return
		}
	}
	overflow = true
	return
}

func MustResolveUDPAddr(addr string) *net.UDPAddr {
	a, err := net.ResolveUDPAddr("udp", addr)
	if err != nil {
		log.Fatal(err)
	}
	return a
}

func MustResolveTCPAddr(addr string) *net.TCPAddr {
	a, err := net.ResolveTCPAddr("tcp", addr)
	if err != nil {
		log.Fatal(err)
	}
	return a
}

type Buf struct {
	Buf *[BufLen]byte
	N   int
}