import logging
import os

from django.contrib.auth import login, views as auth_views
from django.contrib.auth.decorators import login_required
from django.core.exceptions import PermissionDenied, SuspiciousOperation
from django.db.models import Q
from django.http import HttpResponseRedirect
from django.urls import reverse, reverse_lazy
from django.utils.decorators import method_decorator
from django.views import generic

from . import config
from . import forms
from . import models

logger = logging.getLogger(__name__)


class HomeView(generic.TemplateView):
    template_name = 'dav_events/home.html'


class ImprintView(generic.TemplateView):
    template_name = 'dav_events/imprint.html'


class LoginView(auth_views.LoginView):
    form_class = forms.auth.LoginForm
    next_page = reverse_lazy('dav_events:event_list')
    template_name = 'dav_events/auth/login_form.html'

    def get_success_url(self):
        url = self.get_redirect_url()
        return url or self.next_page


class LogoutView(auth_views.LogoutView):
    next_page = reverse_lazy('dav_events:home')


class SetPasswordView(auth_views.PasswordChangeView):
    form_class = forms.auth.SetPasswordForm
    template_name = 'dav_events/auth/set_password_form.html'
    success_url = reverse_lazy('dav_events:event_list')


class EventListView(generic.ListView):
    model = models.Event

    def get_queryset(self):
        user = self.request.user
        if user.is_superuser:
            qs = self.model.objects.all()
        elif user.groups.filter(name=config.MANAGE_ALL_GROUP).count():
            qs = self.model.objects.all()
        else:
            user_sports_list = list()
            for k in ['W', 'S', 'M', 'K', 'B']:
                group_name_var = 'MANAGE_{}_GROUP'.format(k)
                group_name = getattr(config, group_name_var, None)
                if group_name and user.groups.filter(name=group_name).count():
                    user_sports_list.append(k)
            qs = self.model.objects.filter(Q(owner=user) | Q(sport__in=user_sports_list))

        return qs

    @method_decorator(login_required)
    def dispatch(self, request, *args, **kwargs):
        return super(EventListView, self).dispatch(request, *args, **kwargs)


class EventPermissionMixin(object):
    permission = 'view'

    def has_permission(self, permission, obj):
        user = self.request.user

        if user.is_superuser:
            return True

        if permission == 'view':
            if obj.owner == user:
                return True
            if user.groups.filter(name=config.MANAGE_ALL_GROUP).count():
                return True
            group_name_var = 'MANAGE_{}_GROUP'.format(obj.sport)
            group_name = getattr(config, group_name_var, None)
            if group_name and user.groups.filter(name=group_name).count():
                return True
        elif permission in ('edit', 'accept'):
            if user.groups.filter(name=config.MANAGE_ALL_GROUP).count():
                return True
            group_name_var = 'MANAGE_{}_GROUP'.format(obj.sport)
            group_name = getattr(config, group_name_var, None)
            if group_name and user.groups.filter(name=group_name).count():
                return True

        return False

    def enforce_permission(self, obj):
        permission = self.permission
        if not self.has_permission(permission, obj):
            raise PermissionDenied()


class EventDetailView(EventPermissionMixin, generic.DetailView):
    model = models.Event

    def get_object(self, queryset=None):
        obj = super(EventDetailView, self).get_object(queryset=queryset)
        self.enforce_permission(obj)
        return obj

    def get_context_data(self, **kwargs):
        context = super(EventDetailView, self).get_context_data(**kwargs)
        obj = context.get('event')
        context['has_permission_accept'] = self.has_permission('accept', obj)
        context['has_permission_edit'] = self.has_permission('edit', obj)
        return context

    @method_decorator(login_required)
    def dispatch(self, request, *args, **kwargs):
        return super(EventDetailView, self).dispatch(request, *args, **kwargs)


class EventAcceptView(EventDetailView):
    permission = 'accept'

    def accept(self):
        event = self.get_object()
        event.accept()

    def get(self, request, *args, **kwargs):
        self.accept()
        return super(EventAcceptView, self).get(request, *args, **kwargs)


class EventCreateView(generic.FormView):
    form_class = forms.events.EventCreateForm
    template_dir = os.path.join('dav_events', 'event_create')
    default_template_name = 'default.html'
    abort_url = reverse_lazy('dav_events:home')

    def get_template_names(self):
        form = self.get_form()
        form_name = form.form_name
        template = os.path.join(self.template_dir, '{}.html'.format(form_name))
        default_template = os.path.join(self.template_dir, self.default_template_name)
        return [
            template, default_template
        ]

    def get_form_class(self, form_name=None):
        if form_name is not None:
            form_class = getattr(forms.events, form_name)
        elif 'dav_events_event_create_next_form_name' in self.request.session:
            form_name = self.request.session['dav_events_event_create_next_form_name']
            form_class = getattr(forms.events, form_name)
            if not issubclass(form_class, self.form_class):
                raise SuspiciousOperation('Invalid next form: {}'.format(form_name))
        else:
            base_form_class = self.form_class
            initial_form_name = base_form_class.get_initial_form_name()
            form_class = getattr(forms.events, initial_form_name)

        return form_class

    def get_form_kwargs(self):
        kwargs = super(EventCreateView, self).get_form_kwargs()
        if 'request' not in kwargs:
            kwargs['request'] = self.request
        return kwargs

    def get_context_data(self, **kwargs):
        context = super(EventCreateView, self).get_context_data(**kwargs)
        context['abort_url'] = self.abort_url
        return context

    def form_valid(self, form):
        event = form.save()

        next_form_name = form.next_form_name
        if next_form_name:
            self.request.session['dav_events_event_create_next_form_name'] = next_form_name
            next_form_class = self.get_form_class(next_form_name)
            next_form = next_form_class(request=self.request)
            return self.render_to_response(self.get_context_data(form=next_form, event=event))
        else:
            event.save()
            owner = event.owner
            self.clean_session_data()
            if self.request.user.is_authenticated:
                next_url = reverse('dav_events:event_list')
            elif owner.has_usable_password():
                next_url = reverse('dav_events:event_list')
            else:
                login(self.request, owner)
                next_url = reverse('dav_events:set_password')
            return HttpResponseRedirect(next_url)

    def clean_session_data(self, session=None):
        if session is None:
            session = self.request.session
        if 'dav_events_event_create_next_form_name' in session:
            del session['dav_events_event_create_next_form_name']

    def get(self, request, *args, **kwargs):
        self.clean_session_data(request.session)
        return super(EventCreateView, self).get(request, *args, **kwargs)