package hex

import (
	"encoding/hex"

	"smesh.lol/pkg/lol/errorf"
)

var Enc = hex.EncodeToString
var EncBytes = hex.Encode
var Dec = hex.DecodeString
var DecBytes = hex.Decode
var DecLen = hex.DecodedLen

type InvalidByteError = hex.InvalidByteError

// EncAppend encodes src as hex and appends to dst.
func EncAppend(dst, src []byte) []byte {
	l := len(dst)
	dst = append(dst, []byte{:len(src)*2}...)
	hex.Encode(dst[l:], src)
	return dst
}

// DecAppend decodes hex src and appends to dst.
func DecAppend(dst, src []byte) ([]byte, error) {
	if len(src) < 2 {
		return dst, errorf.E([]byte("nothing to decode"))
	}
	if dst == nil {
		dst = []byte{}
	}
	l := len(dst)
	dst = append(dst, []byte{:len(src)/2}...)
	_, err := hex.Decode(dst[l:], src)
	return dst, err
}