--- a/gpp/polls/views.py	Wed May 18 03:04:25 2011 +0000
+++ b/gpp/polls/views.py	Sat May 21 19:55:48 2011 +0000
@@ -1,12 +1,15 @@
-"""Views for the polls application"""
+"""
+Views for the polls application.
 
-from django.shortcuts import render_to_response
-from django.template import RequestContext
+"""
+from django.shortcuts import render
 from django.contrib.auth.decorators import login_required
 from django.shortcuts import get_object_or_404
 from django.http import Http404
 from django.http import HttpResponseRedirect
 from django.core.urlresolvers import reverse
+from django.views.decorators.http import require_POST
+from django.db.models import F
 
 from polls.models import Poll
 from polls.models import Choice
@@ -14,64 +17,89 @@
 
 #######################################################################
 
+def get_user_choice(user, poll):
+    """
+    Return the Choice object the give user voted for from the given poll,
+    or None of no vote has been recorded (or the user is not authenticated.
+
+    """
+    user_choice = None
+    if user.is_authenticated():
+        user_choices = user.choice_set.filter(poll=poll)
+        if user_choices:
+            user_choice = user_choices[0]
+
+    return user_choice
+
+#######################################################################
+
 def poll_index(request):
-   current_polls = Poll.objects.get_current_polls()
-   old_polls = Poll.objects.get_old_polls()
-   return render_to_response('polls/index.html', {
-      'current_polls': current_polls, 
-      'old_polls': old_polls, 
-      },
-      context_instance = RequestContext(request))
+    current_polls = Poll.objects.get_current_polls()
+    old_polls = Poll.objects.get_old_polls()
+    return render(request, 'polls/index.html', {
+        'current_polls': current_polls,
+        'old_polls': old_polls,
+        })
 
 #######################################################################
 
 def poll_detail(request, poll_id):
-   poll = get_object_or_404(Poll, pk = poll_id)
-   if not poll.is_enabled:
-      raise Http404
+    poll = get_object_or_404(Poll, pk=poll_id)
+    if not poll.is_enabled:
+        raise Http404
 
-   return render_to_response('polls/poll.html', {
-      'poll': poll, 
-      },
-      context_instance = RequestContext(request))
+    return render(request, 'polls/poll.html', {
+        'poll': poll,
+        'user_choice': get_user_choice(request.user, poll),
+        })
 
 #######################################################################
 
 @login_required
 def poll_vote(request, poll_id):
-   poll = get_object_or_404(Poll, pk = poll_id)
-   if not poll.is_enabled:
-      raise Http404
-   if not poll.is_open():
-      return HttpResponseRedirect(reverse('polls.views.poll_results', args=[poll_id]))
+    poll = get_object_or_404(Poll, pk=poll_id)
+    if not poll.is_enabled:
+        raise Http404
+    if not poll.is_open():
+        return HttpResponseRedirect(reverse('polls-results', args=[poll_id]))
 
-   if request.method == "POST":
-      vote_form = VoteForm(poll, request.POST)
-      if vote_form.is_valid():
-         choice_id = request.POST.get('choices', None)
-         choice = get_object_or_404(Choice, pk = choice_id)
-         choice.votes += 1
-         choice.save()
-         return HttpResponseRedirect(reverse('polls.views.poll_results', args=[poll_id]))
-   
-   vote_form = VoteForm(poll)
+    user_choice = get_user_choice(request.user, poll)
 
-   return render_to_response('polls/poll_vote.html', {
-      'poll': poll, 
-      'vote_form': vote_form,
-      },
-      context_instance = RequestContext(request))
+    if request.method == "POST":
+        vote_form = VoteForm(poll, request.POST, user=request.user, user_choice=user_choice)
+        if vote_form.is_valid():
+            vote_form.save()
+            return HttpResponseRedirect(reverse('polls-results', args=[poll_id]))
+    else:
+        vote_form = VoteForm(poll)
+
+    return render(request, 'polls/poll_vote.html', {
+        'poll': poll,
+        'vote_form': vote_form,
+        'user_choice': user_choice,
+        })
 
 #######################################################################
 
 def poll_results(request, poll_id):
-   poll = get_object_or_404(Poll, pk = poll_id)
-   total_votes, choices = poll.results()
-   return render_to_response('polls/poll_results.html', {
-      'poll': poll, 
-      'total_votes': total_votes,
-      'choices': choices,
-      },
-      context_instance = RequestContext(request))
+    poll = get_object_or_404(Poll, pk=poll_id)
+    total_votes, choices = poll.results()
+    return render(request, 'polls/poll_results.html', {
+        'poll': poll,
+        'total_votes': total_votes,
+        'choices': choices,
+        'user_choice': get_user_choice(request.user, poll),
+        })
 
 #######################################################################
+
+@require_POST
+@login_required
+def poll_delete_vote(request):
+    poll = get_object_or_404(Poll, pk=request.POST.get('poll_id'))
+    user_choice = get_user_choice(request.user, poll)
+    if user_choice:
+        Choice.objects.filter(id=user_choice.id).update(votes=F('votes') - 1)
+        user_choice.voters.remove(request.user)
+
+    return HttpResponseRedirect(reverse('polls-results', args=[poll.id]))