Encoder. Change \r to \n. Fucking microsoft

encoder.go

package encoder

import (
	"io"
	"io/ioutil"
	"mime/multipart"

	"github.com/dimchansky/utfbom"
	"github.com/sirupsen/logrus"
	"golang.org/x/net/html/charset"
	"golang.org/x/text/transform"
)

type Normalize struct {
	prev byte
}

func (n *Normalize) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
	for nDst < len(dst) && nSrc < len(src) {
		c := src[nSrc]
		switch c {
		case '\r':
			dst[nDst] = '\n'
		case '\n':
			if n.prev == '\r' {
				nSrc++
				n.prev = c
				continue
			}
			dst[nDst] = '\n'
		default:
			dst[nDst] = c
		}
		n.prev = c
		nDst++
		nSrc++
	}
	if nSrc < len(src) {
		err = transform.ErrShortDst
	}
	return
}

func (n *Normalize) Reset() {
	n.prev = 0
}

func EncodedReader(file multipart.File) (t io.Reader, err error) {
	reader := utfbom.SkipOnly(file)
	defer file.Seek(0, io.SeekStart)

	b, err := ioutil.ReadAll(reader)
	if err != nil {
		return t, err
	}

	enc, nname, certain := charset.DetermineEncoding(b, "text/plain")
	logrus.Println("[EncodedReader] enconding detected", nname, "certain: ", certain)

	return transform.NewReader(enc.NewDecoder().Reader(reader), &Normalize{}), nil
}