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

from .models import Choice, Question

# Create your views here.
class IndexView(generic.ListView):
    template_name = 'polls/index.html'
    context_object_name = 'latest_question_list'
    
    def get_queryset(self):
        """
        Return the last five published questions (not including those set to be
        published in the future).
        """
        return Question.objects.filter(pub_date__lte=timezone.now()).order_by('-pub_date')[:5]


class DetailView(LoginRequiredMixin, generic.DetailView):
    model = Question
    template_name = 'polls/detail.html'
    login_url = '/accounts/login/'

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

class ResultsView(generic.DetailView):
    model = Question
    template_name = 'polls/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):
        return render(request, 'polls/detail.html', {
            'question':question,
            'error_message':"You didn't select a choice."
        })
    else:
        selected_choice.votes = F('votes') + 1 #isso resolve o problema de concorrencia que pode dar caso faça selected_choice.votes += 1
        selected_choice.save()
        return HttpResponseRedirect(reverse('polls:results', args=(question_id,)))