Add informative ValueError for sparse fMRI acquisitions missing TR

Author: BitForge95

pipeline/nifti_loader.py

@@ -14,23 +14,30 @@ def __init__(self, file_path, dataset_name):
         super().__init__(file_path, dataset_name)
         self.tr_time = None  # Repetition Time (fMRI's version of sampling rate)
 
-        # COMPOSITION: Plug in the filter engine we built earlier!
         self.filter_engine = StringFilterEngine()
 
     def _parse_bids_metadata(self):
         """
         Automatically extracts RepetitionTime (TR) from the BIDS sidecar JSON.
-        This proves domain expertise in the Brain Imaging Data Structure (BIDS) standard.
+        Includes safety checks for sparse acquisition paradigms where TR is undefined.
         """
-        # A valid BIDS NIfTI (sub-01_task-rest_bold.nii.gz) always has a matching JSON
         base_name = self.file_path.replace(".nii.gz", "").replace(".nii", "")
         json_path = f"{base_name}.json"
 
         if os.path.exists(json_path):
             with open(json_path, "r") as f:
                 metadata = json.load(f)
-                # Safely extract the TR time
                 self.tr_time = metadata.get("RepetitionTime", None)
+
+                # edge case for sparse acquisition
+                if self.tr_time is None:
+                    raise ValueError(
+                        f"\n[{self.dataset_name}] BIDS ERROR: 'RepetitionTime' is missing in the JSON sidecar.\n"
+                        f"NeuroAlign currently requires a defined TR for continuous temporal alignment.\n"
+                        f"Sparse acquisition paradigms (where TR is undefined) are not yet supported. "
+                        f"See BIDS MRI Spec 1.11.1 for details."
+                    )
+
                 print(
                     f"[{self.dataset_name}] BIDS Metadata automatically parsed. TR = {self.tr_time}s"
                 )