fix case rodering

atlas/models.py

@@ -1,6 +1,7 @@
 import json
 import os
 import pathlib
+from typing import Tuple
 
 from django.http import Http404, HttpRequest
 from rad.settings import REMOTE_URL
@@ -521,6 +522,22 @@ class CaseCollection(ExamCollectionGenericBase):
 
         return False
 
+    def get_case_by_index(self, case_index:int, case_count=False) -> Case | Tuple[Case, int]:
+        # Seems to be a bug when case_number is 0 or 1 the same (first) object gets returned
+        # forces a list fixes (but is likely inefficient)
+        cases = list(self.cases.all().order_by("casedetail__sort_order").prefetch_related())
+
+        try:
+            case = cases[case_index]
+        except IndexError:  # Catch an invalid case_number
+            s = f"Invalid case number: {case_index}"
+            raise Http404(s)
+
+        if case_count:
+            return case, len(cases) 
+        else:
+            return case
+
 
 class CaseDetail(models.Model):
     case = models.ForeignKey(Case, on_delete=models.CASCADE)