from datetime import timedelta

from django.contrib import messages
from django.core.urlresolvers import reverse
from django.http import Http404
from django.shortcuts import redirect
from django.utils.functional import cached_property
from django.utils.timezone import now
from django.utils.translation import gettext, ugettext_lazy as _
from django.views.generic import TemplateView, View

from pretix.base.models import (
    CachedFile, CachedTicket, Invoice, Order, OrderPosition,
)
from pretix.base.models.orders import InvoiceAddress
from pretix.base.services.invoices import (
    generate_invoice, invoice_pdf, invoice_qualified,
)
from pretix.base.services.orders import OrderError, cancel_order
from pretix.base.services.tickets import generate
from pretix.base.signals import (
    register_payment_providers, register_ticket_outputs,
)
from pretix.multidomain.urlreverse import eventreverse
from pretix.presale.forms.checkout import InvoiceAddressForm
from pretix.presale.views import CartMixin, EventViewMixin
from pretix.presale.views.async import AsyncAction
from pretix.presale.views.questions import QuestionsViewMixin


class OrderDetailMixin:
    @cached_property
    def order(self):
        try:
            return Order.objects.get(secret=self.kwargs['secret'],
                                     event=self.request.event, code=self.kwargs['order'])
        except Order.DoesNotExist:
            return None

    @cached_property
    def payment_provider(self):
        responses = register_payment_providers.send(self.request.event)
        for receiver, response in responses:
            provider = response(self.request.event)
            if provider.identifier == self.order.payment_provider:
                return provider

    def get_order_url(self):
        return eventreverse(self.request.event, 'presale:event.order', kwargs={
            'order': self.order.code,
            'secret': self.order.secret
        })


class OrderDetails(EventViewMixin, OrderDetailMixin, CartMixin, TemplateView):
    template_name = "pretixpresale/event/order.html"

    def get(self, request, *args, **kwargs):
        self.kwargs = kwargs
        if not self.order:
            raise Http404(_('Unknown order code or not authorized to access this order.'))
        return super().get(request, *args, **kwargs)

    @cached_property
    def download_buttons(self):
        buttons = []
        responses = register_ticket_outputs.send(self.request.event)
        for receiver, response in responses:
            provider = response(self.request.event)
            if not provider.is_enabled:
                continue
            buttons.append({
                'icon': provider.download_button_icon or 'fa-download',
                'text': provider.download_button_text or 'fa-download',
                'identifier': provider.identifier,
            })
        return buttons

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['order'] = self.order
        ctx['can_download'] = (
            self.request.event.settings.ticket_download
            and (
                self.request.event.settings.ticket_download_date is None
                or now() > self.request.event.settings.ticket_download_date
            ) and self.order.status == Order.STATUS_PAID
        )
        ctx['download_buttons'] = self.download_buttons
        ctx['cart'] = self.get_cart(
            answers=True,
            queryset=OrderPosition.objects.filter(order=self.order),
            payment_fee=self.order.payment_fee, payment_fee_tax_rate=self.order.payment_fee_tax_rate
        )
        ctx['invoices'] = list(self.order.invoices.all())
        ctx['can_generate_invoice'] = invoice_qualified(self.order) and (
            self.request.event.settings.invoice_generate == 'user'
        )

        if self.order.status == Order.STATUS_PENDING:
            ctx['payment'] = self.payment_provider.order_pending_render(self.request, self.order)
            ctx['can_retry'] = (
                self.payment_provider.order_can_retry(self.order)
                and self.payment_provider.is_enabled
                and self.order._can_be_paid()
            )
        elif self.order.status == Order.STATUS_PAID:
            ctx['payment'] = self.payment_provider.order_paid_render(self.request, self.order)
            ctx['can_retry'] = False
        return ctx


class OrderPay(EventViewMixin, OrderDetailMixin, TemplateView):
    template_name = "pretixpresale/event/order_pay.html"

    def dispatch(self, request, *args, **kwargs):
        self.request = request
        if not self.order:
            raise Http404(_('Unknown order code or not authorized to access this order.'))
        if (self.order.status not in (Order.STATUS_PENDING, Order.STATUS_EXPIRED)
                or not self.payment_provider.order_can_retry(self.order)
                or not self.payment_provider.is_enabled):
            messages.error(request, _('The payment for this order cannot be continued.'))
            return redirect(self.get_order_url() + '?paid=yes')
        return super().dispatch(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        resp = self.payment_provider.retry_prepare(
            request, self.order
        )
        if isinstance(resp, str):
            return redirect(resp)
        elif resp is True:
            return redirect(self.get_confirm_url())
        else:
            return self.get(request, *args, **kwargs)

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['order'] = self.order
        ctx['form'] = self.form
        return ctx

    @cached_property
    def form(self):
        return self.payment_provider.payment_form_render(self.request)

    def get_confirm_url(self):
        return eventreverse(self.request.event, 'presale:event.order.pay.confirm', kwargs={
            'order': self.order.code,
            'secret': self.order.secret
        })


class OrderInvoiceCreate(EventViewMixin, OrderDetailMixin, View):

    def dispatch(self, request, *args, **kwargs):
        self.request = request
        if not self.order:
            raise Http404(_('Unknown order code or not authorized to access this order.'))
        return super().dispatch(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        if self.request.event.settings.get('invoice_generate') != 'user' or not invoice_qualified(self.order):
            messages.error(self.request, _('You cannot generate an invoice for this order.'))
        elif self.order.invoices.exists():
            messages.error(self.request, _('An invoice for this order already exists.'))
        else:
            i = generate_invoice(self.order)
            self.order.log_action('pretix.event.order.invoice.generated', data={
                'invoice': i.pk
            })
            messages.success(self.request, _('The invoice has been generated.'))
        return redirect(self.get_order_url())


class OrderPayDo(EventViewMixin, OrderDetailMixin, TemplateView):
    template_name = "pretixpresale/event/order_pay_confirm.html"

    def dispatch(self, request, *args, **kwargs):
        self.request = request
        if not self.order:
            raise Http404(_('Unknown order code or not authorized to access this order.'))
        if not self.payment_provider.order_can_retry(self.order) or not self.payment_provider.is_enabled:
            messages.error(request, _('The payment for this order cannot be continued.'))
            return redirect(self.get_order_url())
        if (not self.payment_provider.payment_is_valid_session(request)
                or not self.payment_provider.is_enabled):
            messages.error(request, _('The payment information you entered was incomplete.'))
            return redirect(self.get_payment_url())
        return super().dispatch(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        resp = self.payment_provider.payment_perform(request, self.order)
        return redirect(resp or self.get_order_url())

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['order'] = self.order
        ctx['payment'] = self.payment_provider.checkout_confirm_render(self.request)
        ctx['payment_provider'] = self.payment_provider
        return ctx

    def get_payment_url(self):
        return eventreverse(self.request.event, 'presale:event.order.pay', kwargs={
            'order': self.order.code,
            'secret': self.order.secret
        })


class OrderPayComplete(EventViewMixin, OrderDetailMixin, View):
    def dispatch(self, request, *args, **kwargs):
        self.request = request
        if not self.order:
            raise Http404(_('Unknown order code or not authorized to access this order.'))
        if (not self.payment_provider.payment_is_valid_session(request)
                or not self.payment_provider.is_enabled):
            messages.error(request, _('The payment information you entered was incomplete.'))
            return redirect(self.get_payment_url())
        return super().dispatch(request, *args, **kwargs)

    def get(self, request, *args, **kwargs):
        resp = self.payment_provider.payment_perform(request, self.order)
        return redirect(resp or self.get_order_url() + '?paid=yes')

    def get_payment_url(self):
        return eventreverse(self.request.event, 'presale:event.order.pay', kwargs={
            'order': self.order.code,
            'secret': self.order.secret
        })


class OrderModify(EventViewMixin, OrderDetailMixin, QuestionsViewMixin, TemplateView):
    template_name = "pretixpresale/event/order_modify.html"

    @cached_property
    def positions(self):
        return list(self.order.positions.order_by(
            'item', 'variation'
        ).select_related(
            'item', 'variation'
        ).prefetch_related(
            'variation', 'item__questions', 'answers'
        ))

    @cached_property
    def invoice_address(self):
        try:
            return self.order.invoice_address
        except InvoiceAddress.DoesNotExist:
            return InvoiceAddress(order=self.order)

    @cached_property
    def invoice_form(self):
        return InvoiceAddressForm(data=self.request.POST if self.request.method == "POST" else None,
                                  event=self.request.event,
                                  instance=self.invoice_address)

    def post(self, request, *args, **kwargs):
        failed = not self.save() or not self.invoice_form.is_valid()
        if failed:
            messages.error(self.request,
                           _("We had difficulties processing your input. Please review the errors below."))
            return self.get(request, *args, **kwargs)
        self.invoice_form.save()
        self.order.log_action('pretix.event.order.modified')
        if self.invoice_form.has_changed():
            success_message = ('Your invoice address has been updated. Please contact us if you need us '
                               'to regenerate your invoice.')
            messages.success(self.request, _(success_message))
        return redirect(self.get_order_url())

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

    def dispatch(self, request, *args, **kwargs):
        self.request = request
        self.kwargs = kwargs
        if not self.order:
            raise Http404(_('Unknown order code or not authorized to access this order.'))
        if not self.order.can_modify_answers:
            messages.error(request, _('You cannot modify this order'))
            return redirect(self.get_order_url())
        return super().dispatch(request, *args, **kwargs)

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['order'] = self.order
        ctx['forms'] = self.forms
        ctx['invoice_form'] = self.invoice_form
        return ctx


class OrderCancel(EventViewMixin, OrderDetailMixin, TemplateView):
    template_name = "pretixpresale/event/order_cancel.html"

    def dispatch(self, request, *args, **kwargs):
        self.request = request
        self.kwargs = kwargs
        if not self.order:
            raise Http404(_('Unknown order code or not authorized to access this order.'))
        if self.order.status != Order.STATUS_PENDING or not self.order.can_user_cancel:
            messages.error(request, _('You cannot cancel this order.'))
            return redirect(self.get_order_url())
        return super().dispatch(request, *args, **kwargs)

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

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['order'] = self.order
        return ctx


class OrderCancelDo(EventViewMixin, OrderDetailMixin, AsyncAction, View):
    task = cancel_order

    def get_success_url(self, value):
        return self.get_order_url()

    def get_error_url(self):
        return self.get_order_url()

    def post(self, request, *args, **kwargs):
        if not self.order:
            raise Http404(_('Unknown order code or not authorized to access this order.'))
        if not self.order.can_user_cancel:
            messages.error(request, _('You cannot cancel this order.'))
            return redirect(self.get_order_url())
        return self.do(self.order.pk)

    def get_context_data(self, **kwargs):
        ctx = super().get_context_data(**kwargs)
        ctx['order'] = self.order
        return ctx

    def get_success_message(self, value):
        return _('The order has been cancelled.')

    def get_error_message(self, exception):
        if isinstance(exception, dict) and exception['exc_type'] == 'OrderError':
            return gettext(exception['exc_message'])
        elif isinstance(exception, OrderError):
            return str(exception)
        return super().get_error_message(exception)


class OrderDownload(EventViewMixin, OrderDetailMixin, View):
    @cached_property
    def output(self):
        responses = register_ticket_outputs.send(self.request.event)
        for receiver, response in responses:
            provider = response(self.request.event)
            if provider.identifier == self.kwargs.get('output'):
                return provider

    def get(self, request, *args, **kwargs):
        if not self.output or not self.output.is_enabled:
            messages.error(request, _('You requested an invalid ticket output type.'))
            return redirect(self.get_order_url())
        if not self.order:
            raise Http404(_('Unknown order code or not authorized to access this order.'))
        if self.order.status != Order.STATUS_PAID:
            messages.error(request, _('Order is not paid.'))
            return redirect(self.get_order_url())
        if (not self.request.event.settings.ticket_download
            or (self.request.event.settings.ticket_download_date is not None
                and now() < self.request.event.settings.ticket_download_date)):
            messages.error(request, _('Ticket download is not (yet) enabled.'))
            return redirect(self.get_order_url())

        try:
            ct = CachedTicket.objects.get(order=self.order, provider=self.output.identifier)
        except CachedTicket.DoesNotExist:
            ct = CachedTicket(order=self.order, provider=self.output.identifier)
        try:
            ct.cachedfile
        except CachedFile.DoesNotExist:
            cf = CachedFile()
            cf.date = now()
            cf.expires = self.request.event.date_from + timedelta(days=30)
            cf.save()
            ct.cachedfile = cf
        ct.save()
        generate(self.order.id, self.output.identifier)
        return redirect(reverse('cachedfile.download', kwargs={'id': ct.cachedfile.id}))


class InvoiceDownload(EventViewMixin, OrderDetailMixin, View):

    def get(self, request, *args, **kwargs):
        if not self.order:
            raise Http404(_('Unknown order code or not authorized to access this order.'))

        try:
            invoice = Invoice.objects.get(
                event=self.request.event,
                order=self.order,
                id=self.kwargs['invoice']
            )
        except Invoice.DoesNotExist:
            raise Http404(_('This invoice has not been found'))

        if not invoice.file:
            invoice_pdf(invoice.pk)
            invoice = Invoice.objects.get(pk=invoice.pk)

        if not invoice.file:
            # This happens if we have celery installed and the file will be generated in the background
            messages.warning(request, _('The invoice file has not yet been generated, we will generate it for you '
                                        'now. Please try again in a few seconds.'))
            return redirect(self.get_order_url())

        return redirect(invoice.file.url)