feat(meta): write album art & metadata into destination file

internal/utils/temp.go

@@ -0,0 +1,24 @@
+package utils
+
+import (
+	"fmt"
+	"io"
+	"os"
+)
+
+func WriteTempFile(rd io.Reader, ext string) (string, error) {
+	audioFile, err := os.CreateTemp("", "*"+ext)
+	if err != nil {
+		return "", fmt.Errorf("ffmpeg create temp file: %w", err)
+	}
+
+	if _, err := io.Copy(audioFile, rd); err != nil {
+		return "", fmt.Errorf("ffmpeg write temp file: %w", err)
+	}
+
+	if err := audioFile.Close(); err != nil {
+		return "", fmt.Errorf("ffmpeg close temp file: %w", err)
+	}
+
+	return audioFile.Name(), nil
+}