Fix: Only create destination folder if MP3 files exist in source directory

src/app.py

@@ -38,7 +38,7 @@ def analyze_bpm_librosa(file_path):
     try:
         y, sr = librosa.load(file_path, mono=True)
         tempo, _ = librosa.beat.beat_track(y=y, sr=sr)
-        return int(round(float(tempo[0])))
+        return int(round(float(tempo)))
     except Exception as e:
         print(f"Error analyzing BPM for {file_path.name}: {e}")
         return None
@@ -87,11 +87,6 @@ def main():
         print(f"Error: {source_media_path} is not a valid directory.")
         sys.exit(1)
 
-    parent = source_media_path.parent
-    folder_name = source_media_path.name
-    dest_media_path = parent / f"[CDs-{run_date}]{folder_name}"
-    dest_media_path.mkdir(parents=True, exist_ok=True)
-
     all_tracks = []
     for file in source_media_path.rglob("*.mp3"):
         bpm = get_bpm(file)
@@ -118,6 +113,11 @@ def main():
         print("No MP3 files found.")
         sys.exit(0)
 
+    parent = source_media_path.parent
+    folder_name = source_media_path.name
+    dest_media_path = parent / f"[CDs-{run_date}]{folder_name}"
+    dest_media_path.mkdir(parents=True, exist_ok=True)
+
     total_size = sum(t["size"] for t in all_tracks)
     num_cds = max(1, (total_size + CD_SIZE - 1) // CD_SIZE)