from hmac import compare_digest
from operator import itemgetter

from django.contrib import messages
from django.db.models import F, Max, Min, Window
from django.db.models.functions import RowNumber
from django.http import JsonResponse
from django.shortcuts import redirect
from django.urls import reverse
from django.utils.functional import cached_property
from django.utils.translation import gettext_lazy as _
from django.views.generic import FormView, TemplateView, View
from django.views.generic.detail import SingleObjectMixin
from django_context_decorator import context
from pretalx.common.mixins.views import EventPermissionRequired

from .forms import MusicrateSettingsForm


class JoinView(TemplateView):
    template_name = "pretalx_musicrate/join.html"

    def validate_token(self, token):
        if compare_digest(
            token.encode("utf-8"),
            self.request.event.pretalx_musicrate_settings.join_token.encode("utf-8"),
        ):
            return True
        messages.error(self.request, _("Invalid token"))
        return False

    def get_context_data(self, token_valid=False, **kwargs):
        context = super().get_context_data(**kwargs)
        context["token_valid"] = token_valid
        return context

    def get(self, request, *args, token, **kwargs):
        token_valid = self.validate_token(token)
        return super().get(request, *args, token_valid=token_valid, **kwargs)

    def post(self, request, *args, token, **kwargs):
        token_valid = self.validate_token(token)
        if token_valid:
            return redirect(request.path)
        return self.render_to_response(
            self.get_context_data(token_valid=token_valid, **kwargs)
        )


class MusicrateSettingsView(EventPermissionRequired, FormView):
    permission_required = "orga.change_settings"
    template_name = "pretalx_musicrate/settings.html"
    form_class = MusicrateSettingsForm

    def get_success_url(self):
        return self.request.path

    def get_form_kwargs(self):
        kwargs = super().get_form_kwargs()
        kwargs["event"] = self.request.event
        return kwargs

    def form_valid(self, form):
        form.save()
        messages.success(
            self.request, _("The pretalx-musicrate settings were updated.")
        )
        return super().form_valid(form)


class QRCodeView(EventPermissionRequired, TemplateView):
    permission_required = "orga.view_submissions"
    template_name = "pretalx_musicrate/qrcode.html"

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context["contents"] = self.request.build_absolute_uri(
            reverse(
                "plugins:pretalx_musicrate:join",
                kwargs={
                    "event": self.request.event.slug,
                    "token": self.request.event.pretalx_musicrate_settings.join_token,
                },
            )
        )
        return context


class SubmissionMixin(SingleObjectMixin):
    slug_field = "code"
    slug_url_kwarg = "code"

    def get_queryset(self):
        return self.request.event.submissions.prefetch_related("answers").filter(
            submission_type__in=self.request.event.pretalx_musicrate_settings.submission_types.all()
        )

    @context
    @cached_property
    def submission(self):
        return self.get_object()

    @context
    @cached_property
    def genre(self):
        return (
            self.submission.answers.filter(
                question=self.request.event.pretalx_musicrate_settings.genre_question
            )
            .values_list("answer", flat=True)
            .first()
        )

    @context
    @cached_property
    def origin(self):
        return (
            self.submission.answers.filter(
                question=self.request.event.pretalx_musicrate_settings.origin_question
            )
            .values_list("answer", flat=True)
            .first()
        )

    def get_url_kwargs(self, **kwargs):
        return self.request.resolver_match.kwargs | kwargs

    @context
    @cached_property
    def prev(self):
        prev = (
            self.get_queryset()
            .annotate(prev=Max("created"))
            .filter(created__lt=self.submission.created, created=F("prev"))
            .first()
        )
        if prev is None:
            return None
        return reverse(
            self.request.resolver_match.view_name,
            kwargs=self.get_url_kwargs(code=prev.code),
        )

    @context
    @cached_property
    def index(self):
        return next(
            map(
                itemgetter(1),
                filter(
                    lambda s: s[0] == self.submission.pk,
                    self.get_queryset()
                    .annotate(index=Window(expression=RowNumber(), order_by="created"))
                    .values_list("pk", "index"),
                ),
            )
        )

    @context
    @cached_property
    def count(self):
        return self.get_queryset().count()

    @context
    @cached_property
    def next(self):
        next = (
            self.get_queryset()
            .annotate(next=Min("created"))
            .filter(created__gt=self.submission.created, created=F("next"))
            .first()
        )
        if next is None:
            return None
        return reverse(
            self.request.resolver_match.view_name,
            kwargs=self.get_url_kwargs(code=next.code),
        )


class PresenterView(EventPermissionRequired, SubmissionMixin, TemplateView):
    permission_required = "orga.view_submissions"
    template_name = "pretalx_musicrate/present.html"

    @context
    @property
    def can_continue(self):
        return True

    def get(self, request, *args, **kwargs):
        self.object = self.get_object()
        return super().get(request, *args, **kwargs)


class MayAdvanceView(EventPermissionRequired, View):
    permission_required = "orga.view_submissions"

    def get(self, request, *args, **kwargs):
        return JsonResponse(True, safe=False)