Simplify MusicBrainz Info type and support more tags.

mbz/mbz.go

@@ -8,24 +8,18 @@ import (
 	"github.com/dhowden/tag"
 )
 
-// Info is a structure which contains MusicBrainz identifier information.
-type Info struct {
-	AcoustID     string
-	Album        string
-	AlbumArtist  string
-	Artist       string
-	ReleaseGroup string
-	Track        string
-}
-
-// Supported MusicBrainz tag names
+// Supported MusicBrainz tag names.
 const (
-	TagAcoustID     = "acoustid_id"
-	TagAlbum        = "musicbrainz_albumid"
-	TagAlbumArtist  = "musicbrainz_albumartistid"
-	TagArtist       = "musicbrainz_artistid"
-	TagReleaseGroup = "musicbrainz_releasegroupid"
-	TagTrack        = "musicbrainz_recordingid"
+	AcoustID          = "acoustid_id"
+	AcoustFingerprint = "acoustid_fingerprint"
+	Album             = "musicbrainz_albumid"
+	AlbumArtist       = "musicbrainz_albumartistid"
+	Artist            = "musicbrainz_artistid"
+	Disc              = "musicbrainz_discid"
+	Recording         = "musicbrainz_recordingid"
+	ReleaseGroup      = "musicbrainz_releasegroupid"
+	Track             = "musicbrainz_trackid"
+	TRM               = "musicbrainz_trmid"
 )
 
 // UFIDProviderURL is the URL that we match inside a UFID tag.
@@ -33,41 +27,36 @@ const UFIDProviderURL = "http://musicbrainz.org"
 
 // Mapping between the internal picard tag names and aliases.
 var tags = map[string]string{
-	TagAcoustID:     "Acoustid Id",
-	TagAlbum:        "MusicBrainz Album Id",
-	TagAlbumArtist:  "MusicBrainz Album Artist Id",
-	TagArtist:       "MusicBrainz Artist Id",
-	TagReleaseGroup: "MusicBrainz Release Group Id",
-	TagTrack:        "MusicBrainz Track Id",
+	AcoustID:          "Acoustid Id",
+	AcoustFingerprint: "Acoustid Fingerprint",
+	Album:             "MusicBrainz Album Id",
+	AlbumArtist:       "MusicBrainz Album Artist Id",
+	Artist:            "MusicBrainz Artist Id",
+	Disc:              "MusicBrainz Disc Id",
+	Recording:         "MusicBrainz Track Id",
+	ReleaseGroup:      "MusicBrainz Release Group Id",
+	Track:             "MusicBrainz Release Track Id",
+	TRM:               "MusicBrainz TRM Id",
 }
 
-func (i *Info) set(t, v string) {
-	switch t {
-	case TagAcoustID:
-		i.AcoustID = v
-	case TagAlbum:
-		i.Album = v
-	case TagAlbumArtist:
-		i.AlbumArtist = v
-	case TagArtist:
-		i.Artist = v
-	case TagReleaseGroup:
-		i.ReleaseGroup = v
-	case TagTrack:
-		i.Track = v
-	}
+// Info is a structure which contains MusicBrainz identifier information.
+type Info map[string]string
+
+// Get returns the value for the given MusicBrainz tag.
+func (i Info) Get(tag string) string {
+	return i[tag]
 }
 
-// Set the MusicBrainz tag to the given value.
-func (i *Info) Set(t, v string) {
+// set the MusicBrainz tag to the given value.
+func (i Info) set(t, v string) {
 	if _, ok := tags[t]; ok {
-		i.set(t, v)
+		i[t] = v
 		return
 	}
 
 	for k, tt := range tags {
 		if tt == t {
-			i.set(k, v)
+			i[k] = v
 			return
 		}
 	}
@@ -75,7 +64,7 @@ func (i *Info) Set(t, v string) {
 
 // extractID3 attempts to extract MusicBrainz Picard tags from m.Raw(), where m.Format
 // is assumed to be a supported version of ID3.
-func extractID3(m tag.Metadata) *Info {
+func extractID3(m tag.Metadata) Info {
 	var txxx, ufid string
 	switch m.Format() {
 	case tag.ID3v2_2:
@@ -84,17 +73,17 @@ func extractID3(m tag.Metadata) *Info {
 		txxx, ufid = "TXXX", "UFID"
 	}
 
-	i := &Info{}
+	i := Info{}
 	for k, v := range m.Raw() {
 		switch {
 		case strings.HasPrefix(k, txxx):
 			if str, ok := v.(*tag.Comm); ok {
-				i.Set(str.Description, str.Text)
+				i.set(str.Description, str.Text)
 			}
 		case strings.HasPrefix(k, ufid):
 			if id, ok := v.(*tag.UFID); ok {
 				if id.Provider == UFIDProviderURL {
-					i.Set(TagTrack, string(id.Identifier))
+					i.set(Recording, string(id.Identifier))
 				}
 			}
 		}
@@ -104,11 +93,11 @@ func extractID3(m tag.Metadata) *Info {
 
 // extractMP4Vorbis attempts to extract MusicBrainz Picard tags from m.Raw(), where m.Format
 // is assumed to be MP4 or VORBIS.
-func extractMP4Vorbis(m tag.Metadata) *Info {
-	i := &Info{}
+func extractMP4Vorbis(m tag.Metadata) Info {
+	i := Info{}
 	for t, v := range m.Raw() {
 		if s, ok := v.(string); ok {
-			i.Set(t, s)
+			i.set(t, s)
 		}
 	}
 	return i
@@ -116,7 +105,7 @@ func extractMP4Vorbis(m tag.Metadata) *Info {
 
 // Extract tags created by MusicBrainz Picard which can be used with with the MusicBrainz and LastFM APIs.
 // See https://picard.musicbrainz.org/docs/mappings/ for more information.
-func Extract(m tag.Metadata) *Info {
+func Extract(m tag.Metadata) Info {
 	switch m.Format() {
 	case tag.ID3v2_2, tag.ID3v2_3, tag.ID3v2_4:
 		return extractID3(m)