Validate quiz prerequisite field

2 files changed, 24 insertions, 20 deletions

diff --git a/yaksh/forms.py b/yaksh/forms.py
index 3459be9..14a3db0 100644
--- a/yaksh/forms.py
+++ b/yaksh/forms.py
@@ -181,9 +181,13 @@ class QuizForm(forms.ModelForm):
         user = kwargs.pop('user')
         course_id = kwargs.pop('course')
         super(QuizForm, self).__init__(*args, **kwargs)
-        self.fields['prerequisite'] = forms.ModelChoiceField(
-                queryset=Quiz.objects.filter(course__id=course_id,
-                                             is_trial=False))
+
+        prerequisite_list = Quiz.objects.filter(
+            course__id=course_id,
+            is_trial=False
+        ).exclude(id=self.instance.id)
+
+        self.fields['prerequisite'] = forms.ModelChoiceField(prerequisite_list)
         self.fields['prerequisite'].required = False
         self.fields['course'] = forms.ModelChoiceField(
                 queryset=Course.objects.filter(id=course_id), empty_label=None)
@@ -240,6 +244,12 @@ class QuizForm(forms.ModelForm):
                                                 </p>
                                                 """)
 
+    def clean_prerequisite(self):
+        prereq = self.cleaned_data['prerequisite']
+        if prereq and prereq.prerequisite.id == self.instance.id:
+            raise forms.ValidationError("Please set another prerequisite quiz")
+        return None
+
     class Meta:
         model = Quiz
         exclude = ["is_trial"]
diff --git a/yaksh/views.py b/yaksh/views.py
index 7db0366..8746a57 100644
--- a/yaksh/views.py
+++ b/yaksh/views.py
@@ -256,30 +256,24 @@ def add_quiz(request, course_id, quiz_id=None):
             if form.is_valid():
                 form.save()
                 return my_redirect("/exam/manage/courses/")
-            else:
-                context["form"] = form
-                return my_render_to_response('yaksh/add_quiz.html',
-                                             context,
-                                             context_instance=ci)
+
         else:
             quiz = Quiz.objects.get(id=quiz_id)
             form = QuizForm(request.POST, user=user, course=course_id,
-                            instance=quiz)
+                instance=quiz
+            )
             if form.is_valid():
                 form.save()
-                context["quiz_id"] = quiz_id
                 return my_redirect("/exam/manage/courses/")
+
     else:
-        if quiz_id is None:
-            form = QuizForm(course=course_id, user=user)
-        else:
-            quiz = Quiz.objects.get(id=quiz_id)
-            form = QuizForm(user=user,course=course_id, instance=quiz)
-            context["quiz_id"] = quiz_id
-        context["form"] = form
-        return my_render_to_response('yaksh/add_quiz.html',
-                                     context,
-                                     context_instance=ci)
+        quiz = Quiz.objects.get(id=quiz_id) if quiz_id else None
+        form = QuizForm(user=user,course=course_id, instance=quiz)
+        context["quiz_id"] = quiz_id
+    context["form"] = form
+    return my_render_to_response('yaksh/add_quiz.html',
+                                 context,
+                                 context_instance=ci)
 
 
 @login_required