//go:build windows

package main

import (
	"os"
	"os/exec"

	"golang.org/x/sys/windows"
	"golang.zx2c4.com/wintun"
)

var session wintun.Session
var readWait windows.Handle

func isAdmin() bool {
	f, err := os.Open("\\\\.\\PHYSICALDRIVE0")
	if err != nil {
		return false
	}
	f.Close()
	return true
}

func setupInterface() {
	adapter, err := wintun.CreateAdapter("baalvpn", "Wintun", nil)
	if err != nil {
		panic(err)
	}

	session, err = adapter.StartSession(0x800000)
	if err != nil {
		panic(err)
	}
	readWait = session.ReadWaitEvent()

	if err := exec.Command("netsh", "interface", "ipv6", "add", "address", "interface=baalvpn", "address="+internalIP.String()).Run(); err != nil {
		panic(err)
	}
	if err := exec.Command("netsh", "interface", "ipv6", "set", "interface", "interface=baalvpn", "forwarding=disabled").Run(); err != nil {
		panic(err)
	}
	if err := exec.Command("netsh", "interface", "ipv6", "add", "route", "fd00:baa1::/32", "interface=baalvpn").Run(); err != nil {
		panic(err)
	}
	if err := exec.Command("netsh", "advfirewall", "firewall", "add", "rule", "name=BaalVPN In", "dir=in", "action=allow", "remoteip=fd00:baa1::/32").Run(); err != nil {
		panic(err)
	}
	if err := exec.Command("netsh", "advfirewall", "firewall", "add", "rule", "name=BaalVPN Out", "dir=out", "action=allow", "remoteip=fd00:baa1::/32").Run(); err != nil {
		panic(err)
	}
}

func writePkt(pkt []byte) error {
	sp, err := session.AllocateSendPacket(len(pkt))
	if err != nil {
		return err
	}
	copy(sp, pkt)
	session.SendPacket(sp)
	return nil
}

func readPkt() ([]byte, error) {
	for {
		pkt, err := session.ReceivePacket()
		if err == nil {
			return pkt, nil
		}
		windows.WaitForSingleObject(readWait, windows.INFINITE)
	}
}

func releasePkt(pkt []byte) {
	session.ReleaseReceivePacket(pkt)
}