show error message if the user attempts to add a visit to a marked subject...

show error message if the user attempts to add a visit to a marked subject (deceased, resigned, excluded, etc)

smash/web/views/visit.py

@@ -103,10 +103,15 @@ def visit_add(request, subject_id=-1):
     subject = None
     if len(subjects) > 0:
         subject = subjects[0]
+
     if Visit.objects.filter(subject=subject, is_finished=False).count() > 0:
         messages.add_message(request, messages.WARNING, 'The subject has unfinished visits, please, finish them before adding new visits.')
         return redirect('web.views.subject_visit_details', id=subject_id)
 
+    if not subject.can_schedule():
+        messages.error(request, "Visit cannot be added because the subject status is: {}".format(subject.status))
+        return redirect('web.views.subject_visit_details', id=subject_id)        
+
     if request.method == 'POST':
         form = VisitAddForm(request.POST, request.FILES)
         args = {'form': form}