Refs #131 -- Basic implementation of invoicing

src/pretix/control/forms/event.py

@@ -148,6 +148,26 @@ class EventSettingsForm(SettingsForm):
         help_text=_("Does only work if an invoice address is asked for. VAT ID is not required."),
         required=False
     )
+    invoice_generate = forms.BooleanField(
+        label=_("Generate invoices"),
+        required=False
+    )
+    invoice_address_from = forms.CharField(
+        widget=forms.Textarea(attrs={'rows': 5}), required=False,
+        label=_("Your address"),
+        help_text=_("Will be printed as the sender on invoices. Be sure to include relevant details required in "
+                    "your jurisdiction (e.g. your VAT ID).")
+    )
+    invoice_additional_text = forms.CharField(
+        widget=forms.Textarea(attrs={'rows': 5}), required=False,
+        label=_("Additional text"),
+        help_text=_("Will be printed on every invoice below the invoice total.")
+    )
+    invoice_language = forms.ChoiceField(
+        widget=forms.Select, required=True,
+        label=_("Invoice language"),
+        choices=[('__user__', _('The user\'s language'))] + settings.LANGUAGES,
+    )
     max_items_per_order = forms.IntegerField(
         min_value=1,
         label=_("Maximum number of items per order")

src/pretix/control/templates/pretixcontrol/event/settings.html

@@ -48,6 +48,10 @@
             {% bootstrap_field sform.invoice_address_required layout="horizontal" %}
             {% bootstrap_field sform.invoice_address_vatid layout="horizontal" %}
             {% bootstrap_field sform.tax_rate_default layout="horizontal" %}
+            {% bootstrap_field sform.invoice_generate layout="horizontal" %}
+            {% bootstrap_field sform.invoice_language layout="horizontal" %}
+            {% bootstrap_field sform.invoice_address_from layout="horizontal" %}
+            {% bootstrap_field sform.invoice_additional_text layout="horizontal" %}
         </fieldset>
         <div class="form-group submit-group">
             <button type="submit" class="btn btn-primary btn-save">

src/pretix/control/templates/pretixcontrol/order/index.html

@@ -77,6 +77,19 @@
                         </button>
                     </form>
                 </dd>
+                {% if invoices %}
+                    <dt>{% trans "Invoices" %}</dt>
+                    <dd>
+                        {% for i in invoices %}
+                            <a href="{% url "control:event.invoice.download" invoice=i.pk event=request.event.slug organizer=request.event.organizer.slug %}">
+                                {% if i.is_cancellation %}{% trans "Cancellation" %}{% else %}{% trans "Invoice" %}{% endif %}
+                                {{ i.number }}</a> ({{ i.date|date:"SHORT_DATE_FORMAT" }})
+                            {% if forloop.revcounter0 > 0 %}
+                                <br />
+                            {% endif %}
+                        {% endfor %}
+                    </dd>
+                {% endif %}
             </dl>
         </div>
     </div>

src/pretix/control/urls.py

@@ -70,6 +70,8 @@ urlpatterns = [
         url(r'^orders/(?P<code>[0-9A-Z]+)/$', orders.OrderDetail.as_view(), name='event.order'),
         url(r'^orders/(?P<code>[0-9A-Z]+)/download/(?P<output>[^/]+)$', orders.OrderDownload.as_view(),
             name='event.order.download'),
+        url(r'^invoice/(?P<invoice>[^/]+)$', orders.InvoiceDownload.as_view(),
+            name='event.invoice.download'),
         url(r'^orders/overview/$', orders.OverView.as_view(), name='event.orders.overview'),
         url(r'^orders/export/$', orders.ExportView.as_view(), name='event.orders.export'),
         url(r'^orders/go$', orders.OrderGo.as_view(), name='event.orders.go'),

src/pretix/control/views/orders.py

@@ -5,7 +5,7 @@ from django import forms
 from django.contrib import messages
 from django.core.urlresolvers import reverse
 from django.db.models import Q
-from django.http import HttpResponse, HttpResponseNotAllowed
+from django.http import Http404, HttpResponseNotAllowed
 from django.shortcuts import redirect, render
 from django.utils.functional import cached_property
 from django.utils.timezone import now
@@ -13,10 +13,11 @@ from django.utils.translation import ugettext_lazy as _
 from django.views.generic import DetailView, ListView, TemplateView, View
 
 from pretix.base.models import (
-    CachedFile, CachedTicket, EventLock, Item, Order, Quota,
+    CachedFile, CachedTicket, EventLock, Invoice, Item, Order, Quota,
 )
 from pretix.base.services import tickets
 from pretix.base.services.export import export
+from pretix.base.services.invoices import invoice_pdf
 from pretix.base.services.mail import mail
 from pretix.base.services.orders import cancel_order, mark_order_paid
 from pretix.base.services.stats import order_overview
@@ -118,6 +119,7 @@ class OrderDetail(OrderView):
             and self.order.status == Order.STATUS_PAID
         )
         ctx['payment'] = self.payment_provider.order_control_render(self.request, self.object)
+        ctx['invoices'] = list(self.order.invoices.all())
         return ctx
 
     def get_items(self):
@@ -137,8 +139,8 @@ class OrderDetail(OrderView):
         def keyfunc(pos):
             if (pos.item.admission and self.request.event.settings.attendee_names_asked) \
                     or pos.item.questions.all():
-                return pos.id, 0, 0, 0, None
-            return 0, pos.item_id, pos.variation_id, pos.price, pos.voucher
+                return pos.id, 0, 0, 0, 0, None
+            return 0, pos.item_id, pos.variation_id, pos.price, pos.tax_rate, pos.voucher
 
         positions = []
         for k, g in groupby(sorted(list(cartpos), key=keyfunc), key=keyfunc):
@@ -221,6 +223,38 @@ class OrderResendLink(OrderView):
         return redirect(self.get_order_url())
 
 
+class InvoiceDownload(EventPermissionRequiredMixin, View):
+    permission = 'can_view_orders'
+
+    def get_order_url(self):
+        return reverse('control:event.order', kwargs={
+            'event': self.request.event.slug,
+            'organizer': self.request.event.organizer.slug,
+            'code': self.invoice.order.code
+        })
+
+    def get(self, request, *args, **kwargs):
+        try:
+            self.invoice = Invoice.objects.get(
+                event=self.request.event,
+                id=self.kwargs['invoice']
+            )
+        except Invoice.DoesNotExist:
+            raise Http404(_('This invoice has not been found'))
+
+        if not self.invoice.file:
+            invoice_pdf(self.invoice.pk)
+            self.invoice = Invoice.objects.get(pk=self.invoice.pk)
+
+        if not self.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(self.invoice.file.url)
+
+
 class OrderDownload(OrderView):
 
     @cached_property