skip unsupported files

internal/sorter.go

@@ -9,6 +9,15 @@ import (
 	"strings"
 )
 
+func fileSupported(file string) bool {
+	supported := map[string]bool{
+		".mp3": true, ".flac": true,
+		".m4a": true, ".ogg": true, ".dsf": true,
+	}
+
+	return supported[strings.ToLower(filepath.Ext(file))]
+}
+
 func sortSong(src, dst string) error {
 	m, err := ReadAudioTags(src)
 	if err != nil {