from hmac import compare_digest

from django.contrib import messages
from django.http import JsonResponse
from django.shortcuts import get_object_or_404, redirect
from django.urls import reverse
from django.utils.functional import cached_property
from django.utils.translation import gettext_lazy as _, ngettext
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, RatingForm
from .models import Juror, Rating


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

    def validate_token(self, token):
        try:
            self.juror = Juror.objects.get(token=token)
            return True
        except Juror.DoesNotExist:
            self.juror = None
        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["juror"] = self.juror
        context["token_valid"] = token_valid
        return context

    def get(self, request, *args, token, **kwargs):
        token_valid = self.validate_token(token)
        if self.juror is not None:
            submission = (
                self.juror.last_submission
                or self.request.event.pretalx_musicrate_settings.last_submission
                or self.request.event.submissions.filter(
                    submission_type__in=self.request.event.pretalx_musicrate_settings.submission_types.all()
                )
                .order_by("created")
                .first()
            )
            if submission is not None:
                return redirect(
                    "plugins:pretalx_musicrate:rating",
                    event=self.request.event.slug,
                    token=self.juror.token,
                    code=submission.code,
                )
        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:
            if self.juror is None:
                self.juror = Juror.objects.create(
                    event=self.request.event,
                    last_submission=self.request.event.pretalx_musicrate_settings.last_submission,
                )
            submission = (
                self.juror.last_submission
                or self.request.event.pretalx_musicrate_settings.last_submission
                or self.request.event.submissions.filter(
                    submission_type__in=self.request.event.pretalx_musicrate_settings.submission_types.all()
                )
                .order_by("created")
                .first()
            )
            if submission is not None:
                return redirect(
                    "plugins:pretalx_musicrate:rating",
                    event=self.request.event.slug,
                    token=self.juror.token,
                    code=submission.code,
                )
        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,
                },
            )
        )
        context["last_submission"] = (
            self.request.event.pretalx_musicrate_settings.last_submission
            or self.request.event.submissions.filter(
                submission_type__in=self.request.event.pretalx_musicrate_settings.submission_types.all()
            )
            .order_by("created")
            .first()
        )
        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

    @cached_property
    def index_queryset(self):
        return (
            self.get_queryset()
            .prefetch_related(None)
            .only("pk", "code")
            .order_by("created")
        )

    @context
    @cached_property
    def prev(self):
        if self.index == 1:
            return None
        return reverse(
            self.request.resolver_match.view_name,
            kwargs=self.get_url_kwargs(
                code=self.index_queryset[self.index - 1 - 1].code
            ),
        )

    @context
    @cached_property
    def index(self):
        return next(
            map(
                lambda s: s[0] + 1,
                filter(
                    lambda s: s[1].pk == self.submission.pk,
                    enumerate(self.index_queryset),
                ),
            )
        )

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

    @context
    @cached_property
    def next(self):
        if self.index == self.count:
            return None
        return reverse(
            self.request.resolver_match.view_name,
            kwargs=self.get_url_kwargs(
                code=self.index_queryset[self.index - 1 + 1].code
            ),
        )


class RatingView(FormView, SubmissionMixin):
    template_name = "pretalx_musicrate/rating.html"
    form_class = RatingForm

    @cached_property
    def juror(self):
        return get_object_or_404(
            Juror, token=self.request.resolver_match.kwargs["token"]
        )

    @context
    @cached_property
    def can_continue(self):
        return self.submission.ratings.filter(juror=self.juror).exists()

    def get_form(self, form_class=None):
        if form_class is None:
            form_class = self.get_form_class()
        try:
            instance = Rating.objects.get(submission=self.submission, juror=self.juror)
        except Rating.DoesNotExist:
            instance = None
        return form_class(instance=instance, **self.get_form_kwargs())

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

    def form_valid(self, form):
        obj = form.save(commit=False)
        obj.submission = self.submission
        obj.juror = self.juror
        obj.save()
        try:
            self.juror.last_submission = self.submission
            self.juror.save()
        except Exception:
            pass
        messages.success(self.request, _("Saved!"))
        return super().form_valid(form)

    def get(self, request, *args, **kwargs):
        self.object = self.get_object()
        if (
            (settings := self.request.event.pretalx_musicrate_settings).last_submission
            is not None
            and self.object.created > settings.last_submission.created
        ):
            return redirect(
                self.request.resolver_match.view_name,
                event=self.request.event.slug,
                token=self.juror.token,
                code=settings.last_submission.code,
            )
        return super().get(request, *args, **kwargs)


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()
        if (
            (settings := self.request.event.pretalx_musicrate_settings).last_submission
            is None
            or self.object.created > settings.last_submission.created
        ):
            try:
                settings.last_submission = self.object
                settings.save()
            except Exception:
                pass
        return super().get(request, *args, **kwargs)


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

    def get(self, request, *args, **kwargs):
        num_ratings = self.submission.ratings.count()
        num_jurors = self.request.event.jurors.count()
        return JsonResponse(
            {
                "mayAdvance": num_ratings
                >= int(
                    num_jurors
                    * self.request.event.pretalx_musicrate_settings.advance_threshold
                )
                and num_jurors > 2,
                "statusText": ngettext(
                    "%(num_ratings)d of %(num_jurors)d has rated this submission",
                    "%(num_ratings)d of %(num_jurors)d have rated this submission",
                    num_ratings,
                )
                % {"num_jurors": num_jurors, "num_ratings": num_ratings},
            }
        )