package tool

import (
	"bytes"
	"golang.org/x/text/encoding/simplifiedchinese"
	"golang.org/x/text/transform"
	"io/ioutil"
)

// GbkToUtf8 ...
func GbkToUtf8(str []byte) (b []byte, err error) {
	r := transform.NewReader(bytes.NewReader(str), simplifiedchinese.GBK.NewDecoder())
	b, err = ioutil.ReadAll(r)
	if err != nil {
		return
	}
	return
}

// transform UTF-8 bytes to GBK bytes
func Utf8ToGbk(str []byte) (b []byte, err error) {
	r := transform.NewReader(bytes.NewReader(str), simplifiedchinese.GBK.NewEncoder())
	b, err = ioutil.ReadAll(r)
	if err != nil {
		return
	}
	return
}

// transform GBK string to UTF-8 string and replace it, if transformed success, returned nil error, or died by error message
func StrToUtf8(str string) (string, error) {
	b, err := GbkToUtf8([]byte(str))
	if err != nil {
		return "", err
	}
	return string(b), nil
}

// transform UTF-8 string to GBK string and replace it, if transformed success, returned nil error, or died by error message
func StrToGBK(str string) (string, error) {
	b, err := Utf8ToGbk([]byte(str))
	if err != nil {
		return "", err
	}
	return string(b), nil
}