package gowgpkg

import (
	"fmt"
	"golang.zx2c4.com/wireguard/wgctrl"
	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
	"github.com/vishvananda/netlink"
)

type Device struct {
	Name string
	PublicKey string
	PrivateKey string
	ListenPort int
	IP netlink.Addr
}

func DevicesList() ([]Device, error) {
	client, err := wgctrl.New()
	if err != nil {
		return nil, fmt.Errorf("Can't create wgctrl Client: %w", err)
	}

	devices, err := client.Devices()
	if err != nil {
		return nil, fmt.Errorf("Can't get list of devices: %w", err)
	}

	var devList []Device

	for _, d := range devices {
		dev, err := convertToDevice(d)
		if err != nil {
			return nil, fmt.Errorf("Cant convert wgtypes device to gowgpkg device: %w", err)
		}
		devList = append(devList, dev)
	}

	return devList, nil
}

func DevicesGet(name string) (Device, error) {
	client, err := wgctrl.New()
	if err != nil {
		return Device{}, fmt.Errorf("Can't create wgctrl Client: %w", err)
	}

	device, err := client.Device(name)
	if err != nil {
		return Device{}, fmt.Errorf("Cant get device: %w", err)
	}

	d, err := convertToDevice(device)
	if err != nil {
		return Device{}, err
	}

	return d, nil
}

func DevicesCreate(name string, ip netlink.Addr, privateKey string, listenPort int) (error) {
	// Create IP Device
	la := netlink.NewLinkAttrs()
	la.Name = name

	wgDev := &netlink.GenericLink{
		LinkAttrs: la,
		LinkType:  "wireguard",
	}

	err := netlink.LinkAdd(wgDev)
	if err != nil {
		return fmt.Errorf("Cant create Link to Device: %w", err)
	}

	err = netlink.AddrAdd(wgDev, &ip)
	if err != nil {
		return fmt.Errorf("Cant add ip to device: %w", err)
	}

	privkey, err := wgtypes.ParseKey(privateKey)
	if err != nil {
		return fmt.Errorf("Cant parse private key: %w", err)
	}

	config := wgtypes.Config{
		PrivateKey:   &privkey,
		ListenPort:   &listenPort,
		FirewallMark: nil,
		ReplacePeers: false,
		Peers:        nil,
	}

	client, err := wgctrl.New()
	if err != nil {
		return fmt.Errorf("Cant create wireguard client: %w", err)
	}

	client.ConfigureDevice(name, config)

	err = netlink.LinkSetUp(wgDev)
	if err != nil {
		return fmt.Errorf("Cant start device: %w", err)
	}
	return nil
}

func DeviceDelete(name string) (error) {
	la := netlink.NewLinkAttrs()
	la.Name = name

	dev := &netlink.GenericLink{
		LinkAttrs: la,
		LinkType:  "wireguard",
	}

	err := netlink.LinkDel(dev)
	if err != nil {
		return fmt.Errorf("Cant delete Device: %w", err)
	}

	return nil
}

func convertToDevice(device *wgtypes.Device) (Device, error) {
	d := Device{}
	o, err := netlink.LinkByName(device.Name)
	if err != nil {
		return Device{}, fmt.Errorf("Cant get device: %w", err)
	}
	ips, err := netlink.AddrList(o, 0)
	if err != nil {
		return Device{}, fmt.Errorf("Cant get ip: %w", err)
	}
	d.Name = device.Name
	d.PublicKey = device.PublicKey.String()
	d.PrivateKey = device.PrivateKey.String()
	d.ListenPort = device.ListenPort
	d.IP = ips[0]

	return d, nil
}