added data saving feature

python_app/gui/controllers/app_window_snapshot_mixin.py

@@ -39,23 +39,55 @@ class AppWindowSnapshotMixin:
         return output_dir / "config_profile.json"
 
     def _save_snapshot(self) -> None:
-        """Save runtime snapshot in numpy-directory format."""
+        """Save the last-N runtime measurements as a numpy snapshot (the "Save Dataset" button)."""
         self._drain_runtime_rings_for_snapshot()
 
         if not self._raw_history and not self._pre_history and not self._result_history:
             self._show_error("No runtime data is available for save", details=self._runtime_history_details())
             return
 
+        self._write_snapshot_dataset(
+            list(self._raw_history),
+            list(self._pre_history),
+            list(self._result_history),
+            int(self._save_count.value()),
+        )
+
+    def _snapshot_destination_dir(self) -> Path:
+        """The directory a save/record would create now, from the current path/name fields.
+
+        Used to surface a name clash *before* doing work (manual save and the disk
+        recorder both create this directory and fail if it already exists).
+        """
+        output_root = Path(self._save_path_input.text().strip()).expanduser()
+        return self._store.snapshot_directory(
+            output_root,
+            self._save_name_input.text().strip(),
+            name_prefix=self._radar_config_name_prefix(),
+        )
+
+    def _write_snapshot_dataset(
+        self,
+        raw_history: list,
+        preprocessed_history: list,
+        result_history: list,
+        last_n: int,
+    ) -> None:
+        """Save the given aligned histories as a numpy snapshot + adjacent config profile.
+
+        Shared by the manual "Save Dataset" button (which passes the runtime history)
+        and the on-the-fly disk recorder (which passes the freshly recorded buffers),
+        so both produce byte-identical dataset layouts and identical error reporting.
+        """
         try:
-            last_n = int(self._save_count.value())
             output_root = Path(self._save_path_input.text().strip()).expanduser()
             snapshot_name = self._save_name_input.text().strip()
             snapshot_dir, summary = self._store.save_runtime_snapshot_numpy(
                 output_root,
                 snapshot_name,
-                list(self._raw_history),
-                list(self._pre_history),
-                list(self._result_history),
+                raw_history,
+                preprocessed_history,
+                result_history,
                 last_n,
                 name_prefix=self._radar_config_name_prefix(),
             )