// 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 {
switch m.Format() {
case tag.ID3v2_2, tag.ID3v2_3, tag.ID3v2_4:
return extractID3(m)
}
return extractMP4Vorbis(m)
}
// 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 {
var txxx, ufid string
switch m.Format() {
case tag.ID3v2_2:
txxx, ufid = "TXX", "UFI"
case tag.ID3v2_3, tag.ID3v2_4:
txxx, ufid = "TXXX", "UFID"
}
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)
}
case strings.HasPrefix(k, ufid):
if id, ok := v.(*tag.UFID); ok {
if id.Provider == UFIDProviderURL {
i.set(Recording, string(id.Identifier))
}
}
}
}
return i
}
func printMetadata(m tag.Metadata) {
fmt.Printf("Metadata Format: %v\n", m.Format())
fmt.Printf("File Type: %v\n", m.FileType())
fmt.Printf(" Title: %v\n", m.Title())
fmt.Printf(" Album: %v\n", m.Album())
fmt.Printf(" Artist: %v\n", m.Artist())
fmt.Printf(" Composer: %v\n", m.Composer())
fmt.Printf(" Genre: %v\n", m.Genre())
fmt.Printf(" Year: %v\n", m.Year())
track, trackCount := m.Track()
fmt.Printf(" Track: %v of %v\n", track, trackCount)
disc, discCount := m.Disc()
fmt.Printf(" Disc: %v of %v\n", disc, discCount)
fmt.Printf(" Picture: %v\n", m.Picture())
fmt.Printf(" Lyrics: %v\n", m.Lyrics())
}