fix #27 (core): no write permissions fail

audio_splitter/core.py

@@ -71,6 +71,17 @@ def split_audio(input_file: str, output_directory: str, tracks: List[Dict[str, A
     # --------------------------------------------------------------------------
     os.makedirs(output_directory, exist_ok=True)
 
+    # Check write permission on output directory.
+    try:
+        test_file = os.path.join(output_directory, f'.write_test_{os.getpid()}')
+        with open(test_file, 'w') as f:
+            f.write('test')
+        os.remove(test_file)
+    except PermissionError:
+        raise RuntimeError(
+            f"Error: No write permission for output directory: {output_directory}"
+        )
+
     total_duration = get_audio_duration(input_file)
     stream_info = get_stream_info(input_file)