package tunnel

import (
	"crypto/sha1"

	"github.com/pkg/errors"
	"github.com/xtaci/kcp-go/v5"
	"golang.org/x/crypto/pbkdf2"
)

type ClientConfig struct {
	ServerAddress string
	BlockCrypt    kcp.BlockCrypt
	DataShards    int
	ParityShards  int
	Credentials   interface{}
}

func DefaultClientConfig() *ClientConfig {
	unencryptedBlock, err := kcp.NewNoneBlockCrypt(nil)
	if err != nil { // should never happen
		panic(errors.WithStack(err))
	}

	return &ClientConfig{
		ServerAddress: "127.0.0.1:36543",
		BlockCrypt:    unencryptedBlock,
		DataShards:    3,
		ParityShards:  10,
		Credentials:   nil,
	}
}

func WithClientServerAddress(addr string) ClientConfigFunc {
	return func(conf *ClientConfig) {
		conf.ServerAddress = addr
	}
}

func WithClientCredentials(credentials interface{}) ClientConfigFunc {
	return func(conf *ClientConfig) {
		conf.Credentials = credentials
	}
}

func WithClientAESBlockCrypt(pass, salt string) ClientConfigFunc {
	return func(conf *ClientConfig) {
		key := pbkdf2.Key([]byte(pass), []byte(salt), 1024, 32, sha1.New)

		block, err := kcp.NewAESBlockCrypt(key)
		if err != nil {
			panic(errors.WithStack(err))
		}

		conf.BlockCrypt = block
	}
}

type ClientConfigFunc func(c *ClientConfig)