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)

atlas/views.py

@@ -1177,11 +1177,10 @@ def collection_mark_question(request, pk, case_number):
     if collection.collection_type == "REV":
         raise Http404("Collection in review mode")
 
-    cases = collection.cases.all().order_by("casedetail__sort_order").prefetch_related()
-    case = cases[case_number]
+    case, case_count = collection.get_case_by_index(case_number, case_count=True)
 
     previous = case_number > 0
-    next = case_number < (len(cases) - 1)
+    next = case_number < (case_count - 1)
 
     case_detail = CaseDetail.objects.filter(case=case, collection=collection)
 
@@ -1378,8 +1377,7 @@ def collection_case_view_take(
 
     collection.check_user_can_take(cid, passcode, request)
 
-    cases = collection.cases.all().order_by("casedetail__sort_order").prefetch_related()
-    case = cases[case_number]
+    case, case_count = collection.get_case_by_index(case_number, case_count=True)
 
     cid_user_exam = collection.get_or_create_cid_user_exam(
         cid=cid, user_user=request.user
@@ -1453,7 +1451,7 @@ def collection_case_view_take(
 
     print("case_no")
     previous = case_number > 0
-    next = case_number < (len(cases) - 1)
+    next = case_number < (case_count - 1)
 
     # Set what details a user is / is not able to view when taking the case
     # this can be configured via the collection edit menu
@@ -1521,18 +1519,13 @@ def collection_case_view(request, pk, case_number):
     form = None
     answer = None
 
-    cases = collection.cases.all().order_by("casedetail__sort_order").prefetch_related()
 
-    try:
-        case = cases[case_number]
-    except IndexError:  # Catch an invalid case_number
-        s = f"Invalid case number: {case_number}"
-        raise Http404(s)
+    case, case_count = collection.get_case_by_index(case_number, case_count=True)
 
     series_list = case.series.all().prefetch_related("images", "examination", "plane")
 
     previous = case_number > 0
-    next = case_number < (len(cases) - 1)
+    next = case_number < (case_count - 1)
 
     return render(
         request,
@@ -1540,7 +1533,7 @@ def collection_case_view(request, pk, case_number):
         {
             "form": form,
             "collection": collection,
-            "collection_length": len(cases),
+            "collection_length": case_count,
             "case": case,
             "series_list": series_list,
             "case_number": case_number,