package main

import (
	"flag"
	"fmt"
	"os"

	base14 "github.com/fumiama/go-base16384"
	curve "github.com/fumiama/go-x25519"

	"github.com/fumiama/WireGold/config"
	"github.com/fumiama/WireGold/gold/link"
	"github.com/fumiama/WireGold/helper"
	"github.com/fumiama/WireGold/lower"
)

const suffix32 = "㴄"

func main() {
	help := flag.Bool("h", false, "display this help")
	gen := flag.Bool("g", false, "generate key pair")
	showp := flag.Bool("p", false, "show my publickey")
	file := flag.String("c", "config.yaml", "specify conf file")
	flag.Parse()
	if *help {
		displayHelp("")
	}
	if *gen {
		k, err := curve.New(nil)
		if err != nil {
			panic(err)
		}
		pubk, err := base14.UTF16be2utf8(base14.Encode((*k.Public())[:]))
		if err != nil {
			panic(err)
		}
		prvk, err := base14.UTF16be2utf8(base14.Encode((*k.Private())[:]))
		if err != nil {
			panic(err)
		}
		fmt.Println("PublicKey:", helper.BytesToString(pubk[:57]))
		fmt.Println("PrivateKey:", helper.BytesToString(prvk[:57]))
		os.Exit(0)
	}
	if helper.IsNotExist(*file) {
		f, err := os.Create(*file)
		if err != nil {
			panic(err)
		}
		var r string
		fmt.Print("IP: ")
		fmt.Scanln(&r)
		if r == "" {
			f.Close()
			os.Remove(*file)
			fmt.Println("nil ip")
			return
		}
		f.WriteString("IP: " + r + "\n")
		r = ""

		fmt.Print("SubNet: ")
		fmt.Scanln(&r)
		if r == "" {
			f.Close()
			os.Remove(*file)
			fmt.Println("nil subnet")
			return
		}
		f.WriteString("SubNet: " + r + "\n")
		r = ""

		fmt.Print("PrivateKey: ")
		fmt.Scanln(&r)
		if r == "" {
			f.Close()
			os.Remove(*file)
			fmt.Println("nil private key")
			return
		}
		f.WriteString("PrivateKey: " + r + "\n")
		r = ""

		fmt.Print("EndPoint: ")
		fmt.Scanln(&r)
		if r == "" {
			f.Close()
			os.Remove(*file)
			fmt.Println("nil endpoint")
			return
		}
		f.WriteString("EndPoint: " + r + "\n")
		r = ""

		f.Close()
	}
	c := config.Parse(*file)
	if c.IP == "" {
		displayHelp("nil ip")
	}
	if c.SubNet == "" {
		displayHelp("nil subnet")
	}
	if c.PrivateKey == "" {
		displayHelp("nil private key")
	}
	if c.EndPoint == "" {
		displayHelp("nil endpoint")
	}
	var key [32]byte
	k, err := base14.UTF82utf16be(helper.StringToBytes(c.PrivateKey + suffix32))
	if err != nil {
		panic(err)
	}
	n := copy(key[:], base14.Decode(k))
	if n != 32 {
		displayHelp("private key length is not 32")
	}

	if *showp {
		c := curve.Get(key[:])
		pubk, err := base14.UTF16be2utf8(base14.Encode((*c.Public())[:]))
		if err != nil {
			panic(err)
		}
		fmt.Println("PublicKey:", helper.BytesToString(pubk[:57]))
		os.Exit(0)
	}

	nic := lower.NewNIC(c.IP, c.SubNet)
	me := link.NewMe(&key, c.IP+"/32", c.EndPoint, true)

	for _, peer := range c.Peers {
		var peerkey [32]byte
		k, err := base14.UTF82utf16be(helper.StringToBytes(peer.PublicKey + suffix32))
		if err != nil {
			panic(err)
		}
		n := copy(peerkey[:], base14.Decode(k))
		if n != 32 {
			panic("peer public key length is not 32")
		}
		me.AddPeer(peer.IP, &peerkey, peer.EndPoint, peer.AllowedIPs, peer.KeepAliveSeconds, peer.AllowTrans, true)
	}

	nic.Up()
	defer func() {
		nic.Stop()
		nic.Down()
		nic.Destroy()
	}()

	nic.Start(&me)
}

func displayHelp(hint string) {
	fmt.Println(hint)
	flag.Usage()
	os.Exit(0)
}