append metadata tags after saving tracks

also rewrite requests to monochrome using 2 helper methods

main.go

@@ -11,6 +11,8 @@ import (
 	"path"
 	"strconv"
 	"sync"
+
+	"go.senan.xyz/taglib"
 )
 
 func sendJSON(w http.ResponseWriter, data any, status int) {
@@ -58,7 +60,12 @@ func main() {
 			return
 		}
 
-		if err := os.Mkdir("./music/"+album.Title, 0777); err != nil {
+		albumCoverImg, err := mClient.AlbumCoverImage(album.CoverID)
+		if err != nil {
+			log.Printf("failed to download album cover: %v\n", err)
+		}
+
+		if err := os.Mkdir("./Music/"+album.Title, 0777); err != nil {
 			http.Error(w, fmt.Sprintf("failed to create album directory: %v", err), 500)
 			return
 		}
@@ -107,11 +114,33 @@ func main() {
 					return
 				}
 
-				if err := os.WriteFile(path.Join("./music/", album.Title, track.Item.Title+".flac"), data, 0644); err != nil {
+				fPath := path.Join("./Music/", album.Title, track.Item.Title+".flac")
+				if err := os.WriteFile(fPath, data, 0644); err != nil {
 					log.Printf("failed to save track file: %v\n", err)
 					return
 				}
 
+				artists := []string{}
+				for _, artist := range album.Artists {
+					artists = append(artists, artist.Name)
+				}
+
+				if err := taglib.WriteTags(fPath, map[string][]string{
+					taglib.Artist:      {album.Artist.Name},
+					taglib.Artists:     artists,
+					taglib.AlbumArtist: artists,
+					taglib.TrackNumber: {strconv.Itoa(track.Item.TrackNumber)},
+					taglib.Album:       {album.Title},
+					taglib.Title:       {track.Item.Title},
+					taglib.ReleaseDate: {album.ReleaseDate},
+				}, 0); err != nil {
+					log.Printf("failed to add metadata tags to track file: %v\n", err)
+				}
+
+				if err := taglib.WriteImage(fPath, albumCoverImg); err != nil {
+					log.Printf("failed to add album cover to track metadata: %v\n", err)
+				}
+
 				response.Lock()
 				response.count++
 				response.Unlock()