from urllib.parse import urlencode

from django.urls import reverse
from django.utils import timezone
from django.utils.translation import gettext, gettext_lazy as _
from django.utils.translation import ngettext
from wagtail.admin.ui.tables import Column, DateColumn
from wagtail.admin.ui.tables.pages import PageStatusColumn, PageTitleColumn
from wagtail.admin.views.pages.choose_parent import ChooseParentView
from wagtail.admin.views.pages.listing import IndexView
from wagtail.admin.viewsets.pages import PageListingViewSet

from events.models import EventPage


class EventDateColumn(Column):
    def get_value(self, instance):
        occurrences = list(instance.occurrences.order_by("start"))
        if not occurrences:
            return "—"
        if len(occurrences) == 1:
            local = timezone.localtime(occurrences[0].start)
            return local.strftime(gettext("%Y-%m-%d at %H:%M"))
        count = len(occurrences)
        return ngettext("%(count)d occurrence", "%(count)d occurrences", count) % {"count": count}


class OrganizersColumn(Column):
    def get_value(self, instance):
        names = list(instance.organizers.values_list("name", flat=True))
        if not names:
            return "—"
        if len(names) == 1:
            return names[0]
        return f"{names[0]} (+{len(names) - 1})"


class EventPageIndexView(IndexView):
    def annotate_queryset(self, pages):
        pages = super().annotate_queryset(pages)
        return pages.prefetch_related(
            "occurrences",
            "organizer_links__organizer",
        )


class EventChooseParentView(ChooseParentView):
    """Redirect newly-created EventPages back to the events listing."""

    def _with_next(self, response):
        if response.status_code != 302:
            return response
        url = response["Location"]
        sep = "&" if "?" in url else "?"
        response["Location"] = f"{url}{sep}{urlencode({'next': reverse('events:index')})}"
        return response

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

    def form_valid(self, form):
        return self._with_next(super().form_valid(form))


class EventPageListingViewSet(PageListingViewSet):
    model = EventPage
    index_view_class = EventPageIndexView
    choose_parent_view_class = EventChooseParentView
    icon = "date"
    menu_label = _("Events")
    menu_order = 1
    add_to_admin_menu = True
    ordering = "-latest_revision_created_at"

    columns = [
        PageTitleColumn("title", label=_("Title"), sort_key="title", classname="title"),
        EventDateColumn("event_date", label=_("Date"), width="13%"),
        OrganizersColumn("organizers", label=_("Organizers"), width="12%"),
        DateColumn(
            "latest_revision_created_at",
            label=_("Updated"),
            sort_key="latest_revision_created_at",
            width="10%",
        ),
        PageStatusColumn("status", label=_("Status"), sort_key="live", width="10%"),
    ]


event_page_listing_viewset = EventPageListingViewSet("events")