import dateutil.parser
from django.contrib import messages
from django.core.urlresolvers import reverse
from django.db import transaction
from django.db.models import Max, OuterRef, Subquery
from django.http import Http404, HttpResponseRedirect
from django.shortcuts import get_object_or_404, redirect
from django.utils.functional import cached_property
from django.utils.timezone import make_aware, now
from django.utils.translation import ugettext_lazy as _
from django.views.generic import DeleteView, ListView
from pytz import UTC

from pretix.base.models import Checkin, Order, OrderPosition
from pretix.base.models.checkin import CheckinList
from pretix.control.forms.checkin import CheckinListForm
from pretix.control.forms.filter import CheckInFilterForm
from pretix.control.permissions import EventPermissionRequiredMixin
from pretix.control.views import CreateView, PaginationMixin, UpdateView


class CheckInListShow(EventPermissionRequiredMixin, PaginationMixin, ListView):
    model = Checkin
    context_object_name = 'entries'
    template_name = 'pretixcontrol/checkin/index.html'
    permission = 'can_view_orders'

    def get_queryset(self, filter=True):
        cqs = Checkin.objects.filter(
            position_id=OuterRef('pk'),
            list_id=self.list.pk
        ).order_by().values('position_id').annotate(
            m=Max('datetime')
        ).values('m')

        qs = OrderPosition.objects.filter(
            order__event=self.request.event,
            order__status=Order.STATUS_PAID,
            subevent=self.list.subevent
        ).annotate(
            last_checked_in=Subquery(cqs)
        ).select_related('item', 'variation', 'order', 'addon_to')

        if not self.list.all_products:
            qs = qs.filter(item__in=self.list.limit_products.values_list('id', flat=True))

        if filter and self.filter_form.is_valid():
            qs = self.filter_form.filter_qs(qs)

        return qs

    @cached_property
    def filter_form(self):
        return CheckInFilterForm(
            data=self.request.GET,
            event=self.request.event,
            list=self.list
        )

    def dispatch(self, request, *args, **kwargs):
        self.list = get_object_or_404(self.request.event.checkin_lists.all(), pk=kwargs.get("list"))
        return super().dispatch(request, *args, **kwargs)

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['checkinlist'] = self.list
        ctx['filter_form'] = self.filter_form
        for e in ctx['entries']:
            if e.last_checked_in:
                if isinstance(e.last_checked_in, str):
                    # Apparently only happens on SQLite
                    e.last_checked_in_aware = make_aware(dateutil.parser.parse(e.last_checked_in), UTC)
                else:
                    e.last_checked_in_aware = e.last_checked_in
        return ctx

    def post(self, request, *args, **kwargs):
        if "can_change_orders" not in request.eventpermset:
            messages.error(request, _('You do not have permission to perform this action.'))
            return redirect(reverse('control:event.orders.checkins', kwargs={
                'event': self.request.event.slug,
                'organizer': self.request.event.organizer.slug
            }) + '?' + request.GET.urlencode())

        positions = self.get_queryset(filter=False).filter(
            pk__in=request.POST.getlist('checkin')
        )

        for op in positions:
            created = False
            if op.order.status == Order.STATUS_PAID:
                ci, created = Checkin.objects.get_or_create(position=op, list=self.list, defaults={
                    'datetime': now(),
                })
            op.order.log_action('pretix.control.views.checkin', data={
                'position': op.id,
                'positionid': op.positionid,
                'first': created,
                'datetime': now(),
                'list': self.list.pk
            }, user=request.user)

        messages.success(request, _('The selected tickets have been marked as checked in.'))
        return redirect(reverse('control:event.orders.checkinlists.show', kwargs={
            'event': self.request.event.slug,
            'organizer': self.request.event.organizer.slug,
            'list': self.list.pk
        }) + '?' + request.GET.urlencode())


class CheckinListList(EventPermissionRequiredMixin, PaginationMixin, ListView):
    model = CheckinList
    context_object_name = 'checkinlists'
    permission = 'can_view_orders'
    template_name = 'pretixcontrol/checkin/lists.html'

    def get_queryset(self):
        qs = self.request.event.checkin_lists.prefetch_related("limit_products")
        qs = CheckinList.annotate_with_numbers(qs, self.request.event)

        if self.request.GET.get("subevent", "") != "":
            s = self.request.GET.get("subevent", "")
            qs = qs.filter(subevent_id=s)
        return qs


class CheckinListCreate(EventPermissionRequiredMixin, CreateView):
    model = CheckinList
    form_class = CheckinListForm
    template_name = 'pretixcontrol/checkin/list_edit.html'
    permission = 'can_change_event_settings'
    context_object_name = 'checkinlist'

    def get_success_url(self) -> str:
        return reverse('control:event.orders.checkinlists', kwargs={
            'organizer': self.request.event.organizer.slug,
            'event': self.request.event.slug,
        })

    @transaction.atomic
    def form_valid(self, form):
        form.instance.event = self.request.event
        messages.success(self.request, _('The new check-in list has been created.'))
        ret = super().form_valid(form)
        form.instance.log_action('pretix.event.checkinlist.added', user=self.request.user,
                                 data=dict(form.cleaned_data))
        return ret

    def form_invalid(self, form):
        messages.error(self.request, _('We could not save your changes. See below for details.'))
        return super().form_invalid(form)


class CheckinListUpdate(EventPermissionRequiredMixin, UpdateView):
    model = CheckinList
    form_class = CheckinListForm
    template_name = 'pretixcontrol/checkin/list_edit.html'
    permission = 'can_change_event_settings'
    context_object_name = 'checkinlist'

    def get_object(self, queryset=None) -> CheckinList:
        try:
            return self.request.event.checkin_lists.get(
                id=self.kwargs['list']
            )
        except CheckinList.DoesNotExist:
            raise Http404(_("The requested list does not exist."))

    @transaction.atomic
    def form_valid(self, form):
        messages.success(self.request, _('Your changes have been saved.'))
        if form.has_changed():
            self.object.log_action(
                'pretix.event.checkinlist.changed', user=self.request.user, data={
                    k: form.cleaned_data.get(k) for k in form.changed_data
                }
            )
        return super().form_valid(form)

    def get_success_url(self) -> str:
        return reverse('control:event.orders.checkinlists.show', kwargs={
            'organizer': self.request.event.organizer.slug,
            'event': self.request.event.slug,
            'list': self.object.pk
        })

    def form_invalid(self, form):
        messages.error(self.request, _('We could not save your changes. See below for details.'))
        return super().form_invalid(form)


class CheckinListDelete(EventPermissionRequiredMixin, DeleteView):
    model = CheckinList
    template_name = 'pretixcontrol/checkin/list_delete.html'
    permission = 'can_change_event_settings'
    context_object_name = 'checkinlist'

    def get_object(self, queryset=None) -> CheckinList:
        try:
            return self.request.event.checkin_lists.get(
                id=self.kwargs['list']
            )
        except CheckinList.DoesNotExist:
            raise Http404(_("The requested list does not exist."))

    @transaction.atomic
    def delete(self, request, *args, **kwargs):
        self.object = self.get_object()
        success_url = self.get_success_url()
        self.object.checkins.all().delete()
        self.object.log_action(action='pretix.event.orders.deleted', user=request.user)
        self.object.delete()
        messages.success(self.request, _('The selected list has been deleted.'))
        return HttpResponseRedirect(success_url)

    def get_success_url(self) -> str:
        return reverse('control:event.orders.checkinlists', kwargs={
            'organizer': self.request.event.organizer.slug,
            'event': self.request.event.slug,
        })