implemented fetch call

internal/plugin/interface.go

@@ -147,6 +147,41 @@ func Fetch(source data.Source) (data.MusicObject, error) {
 	return nil, nil
 }
 
+func FetchList(source data.Source) ([]data.MusicObject, error) {
+	res := []data.MusicObject{}
+
+	musicObject, err := Fetch(source)
+	if err != nil {
+		return res, err
+	}
+
+	if a, ok := musicObject.(data.Song); ok {
+		for _, ar := range a.Artists {
+			res = append(res, ar)
+		}
+		if a.Album.Name != "" {
+			res = append(res, a.Album, a)
+		}
+	} else if a, ok := musicObject.(data.Album); ok {
+		for _, ar := range a.Artists {
+			res = append(res, ar)
+		}
+		res = append(res, a)
+		for _, s := range a.Songs {
+			res = append(res, s)
+		}
+	} else if a, ok := musicObject.(data.Artist); ok {
+		res = append(res, a)
+		for _, al := range a.Albums {
+			res = append(res, al)
+		}
+	} else {
+		res = append(res, musicObject)
+	}
+
+	return res, nil
+}
+
 type SearchConfig struct {
 	IgnoreErrors bool
 }