from django.contrib import messages
from django.contrib.auth import authenticate, login, logout
from django.contrib.auth.decorators import permission_required
from django.contrib.auth.models import Group, User
from django.contrib.messages.views import SuccessMessageMixin
from django.core.urlresolvers import reverse, reverse_lazy
from django.db.models import Prefetch
from django.shortcuts import redirect, render
from django.utils.translation import ugettext_lazy as _
from django.views.generic import View
from django.views.generic.edit import CreateView, UpdateView

from kfet.decorators import teamkfet_required

from .forms import GroupForm
from .models import GenericTeamToken


class GenericLoginView(View):
    """
    View to authenticate as kfet generic user.
    """

    def dispatch(self, request, *args, **kwargs):
        return super().dispatch(request, *args, **kwargs)

    def get(self, request, *args, **kwargs):
        """
        GET requests should not change server/client states. Prompt user for
        confirmation.
        """
        return render(
            request,
            "kfet/confirm_form.html",
            {
                "title": _("Ouvrir une session partagée"),
                "text": _(
                    "Êtes-vous sûr·e de vouloir ouvrir une session " "partagée ?"
                ),
            },
        )

    def post(self, request, *args, **kwargs):
        # Issue token, used by GenericBackend.
        token = GenericTeamToken.objects.create_token()

        logout(self.request)

        # Authenticate with GenericBackend. Should always return the kfet
        # generic user.
        user = authenticate(request=self.request, kfet_token=token.token)

        if not user:
            return redirect(self.request.get_full_path())

        # Log in generic user.
        login(self.request, user)
        messages.success(self.request, _("K-Fêt — Ouverture d'une session partagée."))
        return redirect(self.get_next_url())

    def get_next_url(self):
        return self.request.GET.get("next", reverse("kfet.kpsul"))


login_generic = teamkfet_required(GenericLoginView.as_view())


@permission_required("kfet.manage_perms")
def account_group(request):
    user_pre = Prefetch(
        "user_set", queryset=User.objects.select_related("profile__account_kfet")
    )
    groups = Group.objects.filter(name__icontains="K-Fêt").prefetch_related(
        "permissions", user_pre
    )
    return render(request, "kfet/account_group.html", {"groups": groups})


class AccountGroupCreate(SuccessMessageMixin, CreateView):
    model = Group
    template_name = "kfet/account_group_form.html"
    form_class = GroupForm
    success_message = "Nouveau groupe : %(name)s"
    success_url = reverse_lazy("kfet.account.group")


class AccountGroupUpdate(SuccessMessageMixin, UpdateView):
    queryset = Group.objects.filter(name__icontains="K-Fêt")
    template_name = "kfet/account_group_form.html"
    form_class = GroupForm
    success_message = "Groupe modifié : %(name)s"
    success_url = reverse_lazy("kfet.account.group")