package tunnel

import (
	"context"
	"io"
	"net"

	"github.com/pkg/errors"
	"github.com/xtaci/kcp-go/v5"
	"gitlab.com/wpetit/goweb/logger"
)

func pipe(ctx context.Context, client net.Conn, server net.Conn) (err error) {
	stop := make(chan bool)

	go func() {
		err = relay(client, server, stop)
		if err != nil {
			err = errors.WithStack(err)
			logger.Debug(ctx, "client->server error", logger.E(err))
		}
	}()
	go func() {
		err = relay(server, client, stop)
		if err != nil {
			err = errors.WithStack(err)
			logger.Debug(ctx, "server->client error", logger.E(err))
		}
	}()

	select {
	case <-stop:
		return err
	}
}

func relay(src net.Conn, dst net.Conn, stop chan bool) (err error) {
	_, err = io.Copy(dst, src)
	if errors.Is(err, io.EOF) {
		err = nil
	}

	if err != nil {
		err = errors.WithStack(err)
	}

	stop <- true

	return
}

func createBlockCrypt(algorithm string, pass []byte) (kcp.BlockCrypt, error) {
	switch algorithm {
	case "sm4":
		return kcp.NewSM4BlockCrypt(pass[:16])
	case "tea":
		return kcp.NewTEABlockCrypt(pass[:16])
	case "xor":
		return kcp.NewSimpleXORBlockCrypt(pass)
	case "none":
		return kcp.NewNoneBlockCrypt(pass)
	case "aes-128":
		return kcp.NewAESBlockCrypt(pass[:16])
	case "aes-192":
		return kcp.NewAESBlockCrypt(pass[:24])
	case "blowfish":
		return kcp.NewBlowfishBlockCrypt(pass)
	case "twofish":
		return kcp.NewTwofishBlockCrypt(pass)
	case "cast5":
		return kcp.NewCast5BlockCrypt(pass[:16])
	case "3des":
		return kcp.NewTripleDESBlockCrypt(pass[:24])
	case "xtea":
		return kcp.NewXTEABlockCrypt(pass[:16])
	case "salsa20":
		return kcp.NewSalsa20BlockCrypt(pass)
	default:
		return nil, errors.Errorf("unknown algorithm '%s'", algorithm)
	}
}