package main

import (
	"errors"
	"fmt"
	"log"
	"net"

	"golang.zx2c4.com/wireguard/wgctrl"
	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
)

// TODO: replace this with a config value
const deviceName = "wg0"
const allowedNetworkCIDR = "172.16.0.1/20"

func main() {
	client, err := wgctrl.New()
	defer client.Close()

	if err != nil {
		log.Fatalf("Unable to create wireguard client. Is wireguard installed? %v\n", err)
	}

	_, err = client.Device(deviceName)

	if err != nil {
		log.Fatalf("Unable to connect to wireguard device %s. %v\n", deviceName, err)
	}

	log.Println(client.Devices())
	err = addPeer(client, deviceName, "ZmxAOHG+2uLJUooUu8IM6ElTmE4EWjP3eSa0RQqImU8=")
	log.Println(err)
}

func addPeer(client *wgctrl.Client, deviceName string, key string) error {
	_, allowedNetwork, _ := net.ParseCIDR(allowedNetworkCIDR)
	allowedIps := []net.IPNet{*allowedNetwork}
	publicKey, err := wgtypes.ParseKey(key)

	if err != nil {
		return errors.New(fmt.Sprintf("Unable to parse client key %v", err))
	}

	peer := wgtypes.PeerConfig{PublicKey: publicKey, AllowedIPs: allowedIps}

	config := wgtypes.Config{Peers: []wgtypes.PeerConfig{peer}, ReplacePeers: false}
	return client.ConfigureDevice(deviceName, config)
}