Add prerequisites handling to CaseCollection and implement user access checks

atlas/forms.py

@@ -216,6 +216,7 @@ class CaseCollectionForm(ModelForm):
                 "collection_type",
                 "viewer_mode",
                 "question_time_limit",
+                "prerequisites",
             ),
             Fieldset("Valid User Groups", *user_fields) if user_fields else None,
             Div(

atlas/migrations/0079_casecollection_prerequisites.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.1.4 on 2025-10-13 12:31
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('atlas', '0078_cidreportanswer_started_at_and_more'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='casecollection',
+            name='prerequisites',
+            field=models.ManyToManyField(blank=True, help_text='Collections that must be completed before this collection can be taken', related_name='dependents', to='atlas.casecollection'),
+        ),
+    ]

atlas/models.py

@@ -71,6 +71,7 @@ from django.utils import timezone
 import reversion
 
 from django.contrib.contenttypes.fields import GenericRelation
+from django.contrib.contenttypes.models import ContentType
 
 from django.core.validators import MaxValueValidator, MinValueValidator
 
@@ -948,6 +949,15 @@ class CaseCollection(ExamOrCollectionGenericBase):
         help_text="Time limit for answering questions in seconds."
     )
 
+    # Collections that must be completed before this collection can be taken
+    prerequisites = models.ManyToManyField(
+        "self",
+        blank=True,
+        symmetrical=False,
+        related_name="dependents",
+        help_text="Collections that must be completed before this collection can be taken",
+    )
+
     class COLLECTION_TYPE_CHOICES(models.TextChoices):
         REVIEW = (
             "REV",
@@ -1105,6 +1115,49 @@ class CaseCollection(ExamOrCollectionGenericBase):
             kwargs={"pk": self.pk, "case_number": cases.index(case)},
         )
 
+    def check_user_can_take(self, cid, passcode, user=None, active_only=True):
+        """
+        Extend base check_user_can_take to also require completion of any
+        prerequisite collections.
+        """
+        # Perform the normal access checks first
+        super().check_user_can_take(cid, passcode, user=user, active_only=active_only)
+
+        # If there are prerequisites, the user (or CID) must have completed them
+        if not self.prerequisites.exists():
+            return
+
+        for prereq in self.prerequisites.all():
+            # Look up any existing exam record for this user/cid on the prerequisite
+            ct = ContentType.objects.get_for_model(prereq)
+            exam_record = None
+            if cid is not None:
+                # Find CidUser by cid
+                try:
+                    cid_user = CidUser.objects.filter(cid=cid).first()
+                except Exception:
+                    cid_user = None
+
+                if cid_user is None:
+                    exam_record = None
+                else:
+                    exam_record = CidUserExam.objects.filter(
+                        content_type=ct, object_id=prereq.pk, cid_user=cid_user
+                    ).first()
+            else:
+                # Check for a normal user_user exam record
+                exam_record = CidUserExam.objects.filter(
+                    content_type=ct, object_id=prereq.pk, user_user=user
+                ).first()
+
+            if exam_record is None or not getattr(exam_record, "completed", False):
+                # Not allowed to take this collection until prereq completed
+                # Raise the PrerequisiteRequired exception including the prereq object
+                raise PrerequisiteRequired(
+                    f"Collection not available until prerequisite '{prereq.name}' is completed.",
+                    prereq=prereq,
+                )
+
     def get_ohif_dicom_json(self, case_title_as_patient_name=True):
         studies = []
         for n, case in enumerate(self.cases.all()):
@@ -1737,3 +1790,15 @@ class QuestionSchema(models.Model, AuthorMixin):
 
     def __str__(self) -> str:
         return "{}".format(self.name)
+
+
+class PrerequisiteRequired(Exception):
+    """Raised when a user attempts to access a collection but has not completed a prerequisite.
+
+    The exception stores an optional `prereq` attribute pointing to the prerequisite
+    CaseCollection instance so views can render a helpful page linking to it.
+    """
+
+    def __init__(self, message=None, *, prereq=None):
+        super().__init__(message or "Prerequisite required")
+        self.prereq = prereq

atlas/templates/atlas/collection_case_view_take.html

@@ -404,6 +404,14 @@
                     }
                 }
 
+                // If time has already elapsed when the page loads, lock the question and do not autosubmit.
+                if (remaining <= 0) {
+                    console.debug('Timer: time already expired on load, locking without autosubmit');
+                    lockQuestion();
+                    $timer.text(formatTime(0));
+                    return;
+                }
+
                 function formatTime(s) {
                     var mins = Math.floor(s / 60);
                     var secs = s % 60;

atlas/templates/atlas/prerequisite_required.html

@@ -0,0 +1,14 @@
+{% extends 'atlas/base.html' %}
+
+{% block content %}
+  <h2>Collection requires completion of another collection</h2>
+  <p>{{ message }}</p>
+  {% if prereq %}
+    <p>
+      You must complete the collection: <a href="{% url 'atlas:collection_take_start' prereq.pk %}">{{ prereq.name }}</a>
+    </p>
+  {% endif %}
+  <p>
+    If you think this is an error, contact the course administrator.
+  </p>
+{% endblock %}

atlas/views.py

@@ -105,6 +105,7 @@ from .models import (
     SeriesImage,
     UncategorisedDicom,
     UserReportAnswer,
+    PrerequisiteRequired
 )
 from .tables import (
     CaseCollectionTable,
@@ -2197,6 +2198,16 @@ def collection_take_start(request, pk, cid=None, passcode=None):
         valid_user = True
     except Http404:
         valid_user = False
+    except PrerequisiteRequired as e:
+        # Show a friendly page linking to the required collection rather than 404
+        prereq = getattr(e, 'prereq', None)
+        return render(
+            request,
+            'atlas/prerequisite_required.html',
+            {'message': str(e), 'prereq': prereq},
+        )
+
+
     #valid_user = collection.check_logged_in_user(request)
 
 
@@ -2611,7 +2622,11 @@ def collection_take_overview(
     """
     collection = get_object_or_404(CaseCollection, pk=pk)
 
+    try:
         collection.check_user_can_take(cid, passcode, request.user)
+    except PrerequisiteRequired as e:
+        prereq = getattr(e, 'prereq', None)
+        return render(request, 'atlas/prerequisite_required.html', {'message': str(e), 'prereq': prereq})
 
     cid_user_exam = collection.get_or_create_cid_user_exam(
         cid=cid, user_user=request.user
@@ -2684,7 +2699,11 @@ def collection_case_view_take_answers(
     """ """
     collection = get_object_or_404(CaseCollection, pk=pk)
 
+    try:
         collection.check_user_can_take(cid, passcode, request.user)
+    except PrerequisiteRequired as e:
+        prereq = getattr(e, 'prereq', None)
+        return render(request, 'atlas/prerequisite_required.html', {'message': str(e), 'prereq': prereq})
 
     case, case_count = collection.get_case_by_index(case_number, case_count=True)
 
@@ -2733,7 +2752,11 @@ def collection_case_view_take(
     form = None
     answer: None | CidReportAnswer | UserReportAnswer = None
 
+    try:
         collection.check_user_can_take(cid, passcode, request.user)
+    except PrerequisiteRequired as e:
+        prereq = getattr(e, 'prereq', None)
+        return render(request, 'atlas/prerequisite_required.html', {'message': str(e), 'prereq': prereq})
 
     case, case_count = collection.get_case_by_index(case_number, case_count=True)
 
@@ -2818,6 +2841,18 @@ def collection_case_view_take(
                         # If this was a timed-out submission, mark as completed
                         if request.POST.get('timed_out') == '1':
                             answer.completed = True
+                            ## Also mark the overall exam as completed for this user/CID
+                            #try:
+                            #    cid_user_exam.completed = True
+                            #    cid_user_exam.save()
+                            #    # Record an exam status entry
+                            #    collection.exam_user_status.create(
+                            #        cid_user_exam=cid_user_exam,
+                            #        status="submitted",
+                            #        extra="autosubmit",
+                            #    )
+                            #except Exception:
+                            #    logger.exception("Failed to mark cid_user_exam completed on autosubmit")
 
                         answer.save()