feat(uploads): match release groups with MusicBrainz and AcoustID

services/api/internal/library/fingerprint.go

@@ -79,6 +79,37 @@ type FPCalc struct {
 	Timeout time.Duration
 }
 
+// EncodedFingerprint returns compressed Chromaprint for AcoustID. Use ffprobe for full duration.
+func (f FPCalc) EncodedFingerprint(ctx context.Context, absPath string) (string, error) {
+	bin := f.Bin
+	if bin == "" {
+		bin = "fpcalc"
+	}
+	timeout := f.Timeout
+	if timeout <= 0 {
+		timeout = time.Minute
+	}
+	ctx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+	out, err := exec.CommandContext(ctx, bin, "-json", "-length", fmt.Sprint(FingerprintSeconds), "--", absPath).Output()
+	if err != nil {
+		if errors.Is(err, exec.ErrNotFound) {
+			return "", ErrNoFPCalc
+		}
+		return "", fmt.Errorf("fpcalc: encoded fingerprint: %w", err)
+	}
+	var result struct {
+		Fingerprint string `json:"fingerprint"`
+	}
+	if err = json.Unmarshal(out, &result); err != nil {
+		return "", err
+	}
+	if len(result.Fingerprint) == 0 || len(result.Fingerprint) > 65536 || strings.ContainsAny(result.Fingerprint, " \t\r\n") {
+		return "", errors.New("fpcalc: invalid encoded fingerprint")
+	}
+	return result.Fingerprint, nil
+}
+
 // ErrNoFPCalc — fpcalc не установлен: отпечатки Chromaprint не считаются.
 var ErrNoFPCalc = errors.New("library: fpcalc not found")