from django.shortcuts import render,get_object_or_404
from django.http import HttpResponseRedirect
from .models import Choice, Question
from django.db.models import F
from django.urls import reverse
from django.views import generic
from django.utils import timezone
from django.contrib.auth.mixins import LoginRequiredMixin
from django.contrib.auth.decorators import login_required

# Create your views here.
class IndexView(LoginRequiredMixin, generic.ListView):
    template_name = 'polls/index.html'
    context_object_name = 'latest_question_list'

    def get_queryset(self):
        """Return the last five published questions."""
        return Question.objects.filter(
            pub_date__lte=timezone.now()
            ).order_by('-pub_date')[:5]

class DetailView(LoginRequiredMixin, generic.DetailView):
    model = Question
    def get_queryset(self):
        """
        Excludes any questions that aren't published yet.
        """
        return Question.objects.filter(pub_date__lte=timezone.now())

class ResultsView(LoginRequiredMixin, generic.DetailView):
    model = Question
    template_name = 'polls/question_results.html'

@login_required
def vote(request, question_id):
    question = get_object_or_404(Question, pk=question_id)
    try:
        selected_choice = question.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        # Redisplay the question voting form.
        return render(request, 'polls/question_detail.html', {
            'question': question,
            'error_message': "You didn't select a choice.",
        })
    else:
        selected_choice.votes = F('votes') + 1
        selected_choice.save()
        # Always return an HttpResponseRedirect after successfully dealing
        # with POST data. This prevents data from being posted twice if a
        # user hits the Back button.
        return HttpResponseRedirect(reverse('polls:results', args=(question.id,)))
