Pluggable invoice transmission methods (#5020)

* Flexible invoice transmission

* UI work

* Add peppol and output

* API support

* Profile integration

* Simplify form for individuals

* Remove sent_to_customer usage

* more steps

* Revert "Bank transfer: Allow to send the invoice direclty to the accounting department (#2975)"

This reverts commit cea6c340be.

* minor fixes

* Fixes after rebase

* update stati

* Backend view

* Transmit and show status

* status, retransmission

* API retransmission

* More fields

* API docs

* Plugin docs

* Update migration

* Add missing license headers

* Remove dead code, fix current tests

* Run isort

* Update regex

* Rebase migration

* Fix migration

* Add tests, fix bugs

* Rebase migration

* Apply suggestion from @luelista

Co-authored-by: luelista <weller@rami.io>

* Apply suggestion from @luelista

Co-authored-by: luelista <weller@rami.io>

* Apply suggestion from @luelista

Co-authored-by: luelista <weller@rami.io>

* Apply suggestion from @luelista

Co-authored-by: luelista <weller@rami.io>

* Apply suggestion from @luelista

Co-authored-by: luelista <weller@rami.io>

* Make migration reversible

* Add TransmissionType.enforce_transmission

* Fix registries API usage after rebase

* Remove code I forgot to delete

* Update transmission status display depending on type

* Add testmode_supported

* Update src/pretix/static/pretixbase/js/addressform.js

Co-authored-by: luelista <weller@rami.io>

* Update src/pretix/static/pretixbase/js/addressform.js

Co-authored-by: luelista <weller@rami.io>

* Update src/pretix/static/pretixbase/js/addressform.js

Co-authored-by: luelista <weller@rami.io>

* New mechanism for non-required invoice forms

* Update src/pretix/base/invoicing/transmission.py

Co-authored-by: luelista <weller@rami.io>

* Declare testmode_supported for email

* Make transmission_email_other an implementation detail

* Fix failing tests and add new ones

* Update src/pretix/base/services/invoices.py

Co-authored-by: luelista <weller@rami.io>

* Add emails to email history

* Fix comma error

* More generic default email text

* Cleanup

* Remove "email invoices" button and refine logic

* Rebase migration

* Fix edge case

---------

Co-authored-by: luelista <weller@rami.io>

src/pretix/plugins/banktransfer/views.py

@@ -44,18 +44,14 @@ from typing import Set
 
 from django import forms
 from django.contrib import messages
-from django.core.exceptions import ValidationError
-from django.core.validators import validate_email
 from django.db import transaction
 from django.db.models import Count, Q, QuerySet
-from django.http import FileResponse, Http404, JsonResponse
+from django.http import FileResponse, JsonResponse
 from django.shortcuts import get_object_or_404, redirect, render
 from django.urls import reverse
-from django.utils.decorators import method_decorator
 from django.utils.functional import cached_property
 from django.utils.timezone import now
 from django.utils.translation import gettext as _
-from django.views.decorators.clickjacking import xframe_options_exempt
 from django.views.generic import DetailView, FormView, ListView, View
 from django.views.generic.detail import SingleObjectMixin
 from localflavor.generic.forms import BICFormField, IBANFormField
@@ -79,8 +75,6 @@ from pretix.plugins.banktransfer.refund_export import (
     build_sepa_xml, get_refund_export_csv,
 )
 from pretix.plugins.banktransfer.tasks import process_banktransfers
-from pretix.presale.views import EventViewMixin
-from pretix.presale.views.order import OrderDetailMixin
 
 logger = logging.getLogger('pretix.plugins.banktransfer')
 
@@ -892,42 +886,3 @@ class OrganizerSepaXMLExportView(OrganizerPermissionRequiredMixin, OrganizerDeta
             organizer=self.request.organizer,
             pk=self.kwargs.get('id')
         )
-
-
-@method_decorator(xframe_options_exempt, 'dispatch')
-class SendInvoiceMailView(EventViewMixin, OrderDetailMixin, View):
-    def post(self, request, *args, **kwargs):
-        if not self.order:
-            raise Http404(_('Unknown order code or not authorized to access this order.'))
-        try:
-            validate_email(request.POST['email'])
-        except ValidationError:
-            messages.error(request, _('Please enter a valid email address.'))
-            return redirect(self.get_order_url())
-
-        last_payment = self.order.payments.last()
-        if (not last_payment
-                or last_payment.provider != BankTransfer.identifier
-                or last_payment.state != OrderPayment.PAYMENT_STATE_CREATED):
-            messages.error(request, _('No pending bank transfer payment found. Maybe the order has been paid already?'))
-            return redirect(self.get_order_url())
-        if not last_payment.payment_provider.settings.get('invoice_email', as_type=bool):
-            messages.error(request, _('Sending invoices via email is disabled by the event organizer.'))
-            return redirect(self.get_order_url())
-
-        last_invoice = self.order.invoices.last()
-        if not last_invoice:
-            messages.error(request, _('No invoice found, please request an invoice first.'))
-            return redirect(self.get_order_url())
-
-        provider = last_payment.payment_provider
-        provider.send_invoice_to_alternate_email(self.order, last_invoice, request.POST['email'])
-
-        last_payment.info_data = {
-            **last_payment.info_data,
-            'send_invoice_to': request.POST['email'],
-        }
-        last_payment.save(update_fields=['info'])
-
-        messages.success(request, _('Sending the latest invoice via email to {email}.').format(email=request.POST['email']))
-        return redirect(self.get_order_url())