import json
import logging
from collections import OrderedDict
from zipfile import ZipFile

from django.shortcuts import get_object_or_404
from django.urls import reverse
from django.utils.functional import cached_property
from django.utils.translation import gettext_lazy as _
from django.views import View
from django.views.generic import TemplateView

from pretix.base.models import CachedFile
from pretix.base.services.shredder import export, shred
from pretix.base.shredder import ShredError, shred_constraints
from pretix.base.views.tasks import AsyncAction
from pretix.control.permissions import EventPermissionRequiredMixin
from pretix.control.views.user import RecentAuthenticationRequiredMixin

logger = logging.getLogger(__name__)


class ShredderMixin:

    @cached_property
    def shredders(self):
        return OrderedDict(
            sorted(self.request.event.get_data_shredders().items(), key=lambda s: s[1].verbose_name)
        )


class StartShredView(RecentAuthenticationRequiredMixin, EventPermissionRequiredMixin, ShredderMixin, TemplateView):
    permission = 'can_change_orders'
    template_name = 'pretixcontrol/shredder/index.html'

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['shredders'] = self.shredders
        ctx['constraints'] = shred_constraints(self.request.event)
        return ctx


class ShredDownloadView(RecentAuthenticationRequiredMixin, EventPermissionRequiredMixin, ShredderMixin, TemplateView):
    permission = 'can_change_orders'
    template_name = 'pretixcontrol/shredder/download.html'

    def get_context_data(self, **kwargs):
        try:
            cf = CachedFile.objects.get(pk=kwargs['file'])
        except CachedFile.DoesNotExist:
            raise ShredError(_("The download file could no longer be found on the server, please try to start again."))

        with ZipFile(cf.file.file, 'r') as zipfile:
            indexdata = json.loads(zipfile.read('index.json').decode())

        if indexdata['organizer'] != kwargs['organizer'] or indexdata['event'] != kwargs['event']:
            raise ShredError(_("This file is from a different event."))

        shredders = []
        for s in indexdata['shredders']:
            shredder = self.shredders.get(s)
            if not shredder:
                continue
            shredders.append(shredder)

        ctx = super().get_context_data(**kwargs)
        ctx['shredders'] = self.shredders
        ctx['download_on_shred'] = any(shredder.require_download_confirmation for shredder in shredders)
        ctx['file'] = get_object_or_404(CachedFile, pk=kwargs.get("file"))
        return ctx


class ShredExportView(RecentAuthenticationRequiredMixin, EventPermissionRequiredMixin, ShredderMixin, AsyncAction, View):
    permission = 'can_change_orders'
    task = export
    known_errortypes = ['ShredError']

    def get_success_message(self, value):
        return None

    def get_success_url(self, value):
        return reverse('control:event.shredder.download', kwargs={
            'event': self.request.event.slug,
            'organizer': self.request.event.organizer.slug,
            'file': str(value)
        })

    def get_error_url(self):
        return reverse('control:event.shredder.start', kwargs={
            'event': self.request.event.slug,
            'organizer': self.request.event.organizer.slug
        })

    def post(self, request, *args, **kwargs):
        constr = shred_constraints(self.request.event)
        if constr:
            return self.error(ShredError(self.get_error_url()))

        return self.do(self.request.event.id, request.POST.getlist("shredder"), self.request.session.session_key)


class ShredDoView(RecentAuthenticationRequiredMixin, EventPermissionRequiredMixin, ShredderMixin, AsyncAction, View):
    permission = 'can_change_orders'
    task = shred
    known_errortypes = ['ShredError']

    def get_success_url(self, value):
        return reverse('control:event.shredder.start', kwargs={
            'event': self.request.event.slug,
            'organizer': self.request.event.organizer.slug,
        })

    def get_success_message(self, value):
        return _('The selected data was deleted successfully.')

    def get_error_url(self):
        return reverse('control:event.shredder.download', kwargs={
            'event': self.request.event.slug,
            'organizer': self.request.event.organizer.slug,
            'file': self.request.POST.get("file")
        })

    def post(self, request, *args, **kwargs):
        constr = shred_constraints(self.request.event)
        if constr:
            return self.error(ShredError(self.get_error_url()))

        if request.event.slug != request.POST.get("slug"):
            return self.error(ShredError(_("The slug you entered was not correct.")))

        return self.do(self.request.event.id, request.POST.get("file"), request.POST.get("confirm_code"))