refactor: decouple tag writers from deezer models

internal/tag/flac.go

@@ -0,0 +1,84 @@
+package tag
+
+import (
+	"os"
+	"strings"
+
+	"github.com/go-flac/flacpicture/v2"
+	"github.com/go-flac/flacvorbis/v2"
+	"github.com/go-flac/go-flac/v2"
+)
+
+type flacTagger struct {
+	file  *flac.File
+	cmts  *flacvorbis.MetaDataBlockVorbisComment
+	index int
+	path  string
+}
+
+func (t *flacTagger) write(m Metadata) error {
+	if m.Album != nil {
+		date := m.Album.ReleaseDate
+		if parts := strings.Split(date, "-"); len(parts) == 3 {
+			date = parts[0]
+		}
+
+		t.addTag("TRACKNUMBER", m.TrackNumber)
+		t.addTag("ALBUMARTIST", m.Album.Artist)
+		t.addTag("ALBUM", m.Album.Title)
+		t.addTag("PUBLISHER", m.Album.Label)
+		t.addTag("ORIGINALDATE", m.Album.OriginalReleaseDate)
+		t.addTag("DATE", date)
+		t.addTag("COMMENT", m.Album.ProducerLine)
+		t.addTag("COPYRIGHT", m.Album.Copyright)
+	}
+
+	t.addTag("ARTIST", m.Artists)
+	t.addTag("TITLE", m.Title)
+	t.addTag("COMPOSER", m.Composers)
+	t.addTag("LYRICIST", m.Lyricists)
+	t.addTag("GENRE", m.Genre)
+	t.addTag("REPLAYGAIN_TRACK_GAIN", m.Gain)
+	t.addTag("ISRC", m.ISRC)
+	t.addTag("BPM", m.BPM)
+	t.addTag("KEY", m.Key)
+	t.addTag("INITIALKEY", m.Key)
+
+	cmtsMeta := t.cmts.Marshal()
+	if t.index > 0 {
+		t.file.Meta[t.index] = &cmtsMeta
+	} else {
+		t.file.Meta = append(t.file.Meta, &cmtsMeta)
+	}
+
+	picture, err := flacpicture.NewFromImageData(flacpicture.PictureTypeFrontCover, "Front cover", m.Cover, "image/jpeg")
+	if err != nil {
+		return err
+	}
+	pictureMeta := picture.Marshal()
+	t.file.Meta = append(t.file.Meta, &pictureMeta)
+
+	tmpPath := t.path + ".tmp"
+	if err := t.file.Save(tmpPath); err != nil {
+		return err
+	}
+	return os.Rename(tmpPath, t.path)
+}
+
+func (t *flacTagger) addTag(name, value string) {
+	if value != "" {
+		t.cmts.Add(name, value)
+	}
+}
+
+func extractFLACComment(file *flac.File) (*flacvorbis.MetaDataBlockVorbisComment, int) {
+	for idx, meta := range file.Meta {
+		if meta.Type == flac.VorbisComment {
+			cmt, err := flacvorbis.ParseFromMetaDataBlock(*meta)
+			if err == nil {
+				return cmt, idx
+			}
+		}
+	}
+	return nil, 0
+}

internal/tag/id3v2.go

@@ -0,0 +1,70 @@
+package tag
+
+import (
+	"fmt"
+	"strconv"
+
+	"github.com/bogem/id3v2/v2"
+)
+
+type id3v2Tagger struct {
+	tag *id3v2.Tag
+}
+
+func (t *id3v2Tagger) write(m Metadata) error {
+	defer t.tag.Close()
+
+	duration, err := strconv.Atoi(m.Duration)
+	if err != nil {
+		return err
+	}
+	length := fmt.Sprintf("%d", duration*1000)
+
+	if m.Album != nil {
+		t.addTag("TRCK", m.TrackNumber)
+		t.addTag("TPE2", m.Album.Artist)
+		t.addTag("TALB", m.Album.Title)
+		t.addTag("TPUB", m.Album.Label)
+		t.addTag("TDOR", m.Album.OriginalReleaseDate)
+		t.addTag("TYER", m.Album.ReleaseDate)
+		t.addTag("COMM", m.Album.ProducerLine)
+		t.addTag("TCOP", m.Album.Copyright)
+	}
+
+	t.addTag("TPE1", m.Artists)
+	t.addTag("TIT2", m.Title)
+	t.addTag("TCOM", m.Composers)
+	t.addTag("TEXT", m.Lyricists)
+	t.addTag("TCON", m.Genre)
+	t.addTag("TLEN", length)
+	t.addTag("TBPM", m.BPM)
+	t.addTag("TKEY", m.Key)
+	t.addTXXX("GAIN", m.Gain)
+	t.addTXXX("ISRC", m.ISRC)
+
+	t.tag.AddAttachedPicture(id3v2.PictureFrame{
+		Encoding:    t.tag.DefaultEncoding(),
+		MimeType:    "image/jpeg",
+		PictureType: id3v2.PTFrontCover,
+		Description: "Cover",
+		Picture:     m.Cover,
+	})
+
+	return t.tag.Save()
+}
+
+func (t *id3v2Tagger) addTag(name, value string) {
+	if value != "" {
+		t.tag.AddTextFrame(name, t.tag.DefaultEncoding(), value)
+	}
+}
+
+func (t *id3v2Tagger) addTXXX(description, value string) {
+	if value != "" {
+		t.tag.AddUserDefinedTextFrame(id3v2.UserDefinedTextFrame{
+			Encoding:    t.tag.DefaultEncoding(),
+			Description: description,
+			Value:       value,
+		})
+	}
+}

internal/tag/tag.go

@@ -0,0 +1,69 @@
+package tag
+
+import (
+	"path"
+
+	"github.com/bogem/id3v2/v2"
+	"github.com/go-flac/flacvorbis/v2"
+	"github.com/go-flac/go-flac/v2"
+)
+
+type AlbumMetadata struct {
+	Artist              string
+	Title               string
+	Label               string
+	OriginalReleaseDate string
+	ReleaseDate         string
+	ProducerLine        string
+	Copyright           string
+}
+
+type Metadata struct {
+	Title       string
+	Artists     string
+	Composers   string
+	Lyricists   string
+	Genre       string
+	BPM         string
+	Key         string
+	TrackNumber string
+	Duration    string
+	Gain        string
+	ISRC        string
+	Cover       []byte
+	Album       *AlbumMetadata
+}
+
+type tagger interface {
+	write(m Metadata) error
+}
+
+func newTagger(filePath string) (tagger, error) {
+	if path.Ext(filePath) == ".mp3" {
+		tag, err := id3v2.Open(filePath, id3v2.Options{Parse: true})
+		if err != nil {
+			return nil, err
+		}
+		return &id3v2Tagger{tag: tag}, nil
+	}
+
+	file, err := flac.ParseFile(filePath)
+	if err != nil {
+		return nil, err
+	}
+
+	cmts, idx := extractFLACComment(file)
+	if cmts == nil {
+		cmts = flacvorbis.New()
+	}
+
+	return &flacTagger{file: file, cmts: cmts, index: idx, path: filePath}, nil
+}
+
+func Write(filePath string, m Metadata) error {
+	t, err := newTagger(filePath)
+	if err != nil {
+		return err
+	}
+	return t.write(m)
+}