//go:build windows
// +build windows

package water

import (
	"log"
	"net/netip"

	"golang.org/x/sys/windows"
	"golang.zx2c4.com/wireguard/tun"
	"golang.zx2c4.com/wireguard/windows/tunnel/winipcfg"
)

type wintun struct {
	dev tun.Device
}

func (w *wintun) Close() error {
	return w.dev.Close()
}

func (w *wintun) Write(b []byte) (int, error) {
	return w.dev.Write(b, 0)
}

func (w *wintun) Read(b []byte) (int, error) {
	return w.dev.Read(b, 0)
}

func openDev(config Config) (ifce *Interface, err error) {
	if config.DeviceType == TAP {
		return nil, err
	}
	id := &windows.GUID{
		0x0000000,
		0xFFFF,
		0xFFFF,
		[8]byte{0xFF, 0xe9, 0x76, 0xe5, 0x8c, 0x74, 0x06, 0x3e},
	}
	dev, err := tun.CreateTUNWithRequestedGUID(config.PlatformSpecificParams.Name, id, 0)
	if err != nil {
		return nil, err
	}
	nativeTunDevice := dev.(*tun.NativeTun)
	link := winipcfg.LUID(nativeTunDevice.LUID())

	networks := config.PlatformSpecificParams.Network
	if len(networks) == 0 {
		panic("network is empty")
	}
	// set ip addresses
	ipPrefix := []netip.Prefix{}
	for _, n := range networks {
		ip, err := netip.ParsePrefix(n)
		if err != nil {
			panic(err)
		}
		ipPrefix = append(ipPrefix, ip)
	}
	err = link.SetIPAddresses(ipPrefix)
	if err != nil {
		panic(err)
	}
	// set dns
	servers := []netip.Addr{}
	s1, _ := netip.ParseAddr("8.8.8.8")
	s2, _ := netip.ParseAddr("1.1.1.1")
	servers = append(servers, s1)
	servers = append(servers, s2)
	domains := []string{"wintun.dns"}
	log.Printf("set dns servers:%v domain:%v", servers, domains)
	err = link.SetDNS(windows.AF_INET, servers, domains)
	if err != nil {
		panic(err)
	}

	wintun := &wintun{dev: dev}
	ifce = &Interface{isTAP: (config.DeviceType == TAP), ReadWriteCloser: wintun}
	return ifce, nil
}