Postpaid follow up email (#4712)

This adds an email for challenge organizers and the invoice contact
person that informs them of the approaching follow_up date for post-paid
invoices and the consequences of this date. The email is sent every 2
weeks (if necessary, i.e. for initialized post-paid invoices with an
approaching follow-up date).

Part of DIAGNijmegen/rse-roadmap#475

Author: amickan

app/config/settings.py

@@ -1250,6 +1250,10 @@ def get_private_ip():
         "task": "grandchallenge.invoices.tasks.send_challenge_invoice_overdue_reminder_emails",
         "schedule": crontab(day_of_month=1, hour=6, minute=0),
     },
+    "send_post_paid_invoice_follow_up_emails": {
+        "task": "grandchallenge.invoices.tasks.send_post_paid_invoice_follow_up_emails",
+        "schedule": crontab(day_of_month="1,14", hour=5, minute=0),
+    },
     "send_challenge_request_draft_reminder_emails": {
         "task": "grandchallenge.challenges.tasks.send_challenge_request_draft_reminder_emails",
         "schedule": crontab(day_of_month="1,14", hour=6, minute=0),

app/grandchallenge/invoices/emails.py

@@ -4,6 +4,7 @@
 from django.contrib.sites.models import Site
 from django.core.mail import mail_managers
 from django.template.loader import render_to_string
+from django.utils.formats import date_format
 from django.utils.html import format_html
 
 from grandchallenge.emails.emails import send_standard_email_batch
@@ -93,3 +94,30 @@ def send_challenge_invoice_issued_notification(invoice):
         recipients=recipients,
         subscription_type=EmailSubscriptionTypes.SYSTEM,
     )
+
+
+def send_postpaid_invoice_follow_up_date_approaching_email(invoice):
+    subject = format_html(
+        "[{challenge_name}] Post-paid invoice date approaching",
+        challenge_name=invoice.challenge.short_name,
+    )
+    message = render_to_string(
+        "invoices/partials/post_paid_invoice_follow_up_email.md",
+        context={
+            "challenge_name": invoice.challenge.short_name,
+            "follow_up_on_date": date_format(invoice.follow_up_on, "F jS Y"),
+            "billing_address": invoice.billing_address,
+            "contact_name": invoice.contact_name,
+            "contact_email": invoice.contact_email,
+            "vat_number": invoice.vat_number,
+        },
+    )
+    recipients = get_challenge_invoice_recipients(invoice)
+
+    send_standard_email_batch(
+        site=Site.objects.get_current(),
+        subject=subject,
+        markdown_message=message,
+        recipients=recipients,
+        subscription_type=EmailSubscriptionTypes.SYSTEM,
+    )

app/grandchallenge/invoices/tasks.py

@@ -1,3 +1,4 @@
+from dateutil.relativedelta import relativedelta
 from django.core.mail import mail_managers
 from django.db import transaction
 from django.template.loader import render_to_string
@@ -10,6 +11,7 @@
 from grandchallenge.invoices.emails import (
     send_challenge_invoice_issued_notification,
     send_challenge_invoice_overdue_reminder,
+    send_postpaid_invoice_follow_up_date_approaching_email,
 )
 
 
@@ -80,3 +82,17 @@ def send_open_invoices_email():
         subject=subject,
         message=message,
     )
+
+
+@acks_late_micro_short_task
+@transaction.atomic
+def send_post_paid_invoice_follow_up_emails():
+    from grandchallenge.invoices.models import Invoice
+
+    invoices = Invoice.objects.filter(
+        payment_type=Invoice.PaymentTypeChoices.POSTPAID,
+        payment_status=Invoice.PaymentStatusChoices.INITIALIZED,
+        follow_up_on__lte=now().date() + relativedelta(months=1, days=1),
+    )
+    for invoice in invoices:
+        send_postpaid_invoice_follow_up_date_approaching_email(invoice)

app/grandchallenge/invoices/templates/invoices/partials/post_paid_invoice_follow_up_email.md

@@ -0,0 +1,24 @@
+We're writing to let you know that a post-paid invoice for your challenge {{challenge_name}} is scheduled to be issued
+on {{follow_up_on_date}}.
+
+The invoice amount will be based on your usage up to that date and will be rounded up to the nearest €250.
+If your challenge has not incurred any costs beyond what has already been invoiced, no further invoice will be sent.
+
+We have the following billing details on file for this invoice. Please let us know if any of those details are
+incorrect.
+
+**Billing address:**
+{{billing_address}}
+**Contact name:**
+{{contact_name}}
+**Contact email:**
+{{contact_email}}
+**VAT number:**
+{{vat_number}}
+
+Please note that this invoice marks the end of your challenge. Once it has been issued, any remaining post-paid budget —
+beyond any excess within the €250 block — will no longer be valid and your challenge will be closed for new submissions.
+If you would like to keep your challenge open, please get in touch to arrange a new post-paid capacity reservation.
+
+If you have any questions or would like to make changes before the invoice is issued, please reply to this email and we
+will be happy to help.

app/tests/invoices_tests/test_tasks.py

@@ -1,14 +1,18 @@
+from unittest.mock import MagicMock, call
 from zoneinfo import ZoneInfo
 
 import pytest
+from dateutil.utils import today
 from django.core import mail
+from django.utils.formats import date_format
 from django.utils.timezone import datetime, now, timedelta
 
 from grandchallenge.invoices.models import Invoice
 from grandchallenge.invoices.tasks import (
     send_challenge_invoice_issued_notification_emails,
     send_challenge_invoice_overdue_reminder_emails,
     send_open_invoices_email,
+    send_post_paid_invoice_follow_up_emails,
 )
 from tests.factories import ChallengeFactory, UserFactory
 from tests.invoices_tests.factories import InvoiceFactory
@@ -449,3 +453,102 @@ def test_send_open_invoices_email_not_sent_when_no_invoices(settings):
     send_open_invoices_email()
 
     assert len(mail.outbox) == 0
+
+
+@pytest.mark.django_db
+def test_send_post_paid_invoice_follow_up_emails_content():
+    challenge = ChallengeFactory()
+    challenge_admin = challenge.creator
+    contact_email = "contact_person@example.com"
+
+    invoice = InvoiceFactory(
+        challenge=challenge,
+        support_costs_euros=0,
+        compute_costs_euros=10,
+        storage_costs_euros=0,
+        payment_type=Invoice.PaymentTypeChoices.POSTPAID,
+        payment_status=Invoice.PaymentStatusChoices.INITIALIZED,
+        follow_up_on=today() + timedelta(days=1),
+        contact_email=contact_email,
+        contact_name="John Doe",
+        billing_address="Some Street 12, 12345 SomeCity, SomeCountry",
+        vat_number="12345",
+    )
+
+    send_post_paid_invoice_follow_up_emails()
+
+    expected_subject = (
+        "[{challenge_name}] Post-paid invoice date approaching".format(
+            challenge_name=challenge.short_name,
+        )
+    )
+
+    # challenge admin and invoice contact person are emailed
+    assert len(mail.outbox) == 2
+    for email in mail.outbox:
+        assert expected_subject in email.subject
+        assert date_format(invoice.follow_up_on, "F jS Y") in email.body
+        assert invoice.billing_address in email.body
+        assert invoice.contact_name in email.body
+        assert invoice.contact_email in email.body
+        assert invoice.vat_number in email.body
+
+    recipient_emails = [email.to[0] for email in mail.outbox]
+    assert challenge_admin.email in recipient_emails
+    assert contact_email in recipient_emails
+
+
+@pytest.mark.django_db
+def test_send_post_paid_invoice_follow_up_emails_queryset(mocker):
+    challenge = ChallengeFactory()
+
+    postpaid_relevant = InvoiceFactory(
+        challenge=challenge,
+        payment_type=Invoice.PaymentTypeChoices.POSTPAID,
+        payment_status=Invoice.PaymentStatusChoices.INITIALIZED,
+        follow_up_on=today() + timedelta(days=1),
+    )
+    # create a bunch of other invoices that should not trigger an email
+    InvoiceFactory(
+        challenge=challenge,
+        payment_type=Invoice.PaymentTypeChoices.POSTPAID,
+        payment_status=Invoice.PaymentStatusChoices.INITIALIZED,
+        follow_up_on=today() + timedelta(days=50),
+    )
+    InvoiceFactory(
+        challenge=challenge,
+        payment_type=Invoice.PaymentTypeChoices.POSTPAID,
+        payment_status=Invoice.PaymentStatusChoices.REQUESTED,
+    )
+    InvoiceFactory(
+        challenge=challenge,
+        payment_type=Invoice.PaymentTypeChoices.POSTPAID,
+        payment_status=Invoice.PaymentStatusChoices.ISSUED,
+    )
+    InvoiceFactory(
+        challenge=challenge,
+        payment_type=Invoice.PaymentTypeChoices.POSTPAID,
+        payment_status=Invoice.PaymentStatusChoices.PAID,
+    )
+    InvoiceFactory(
+        challenge=challenge,
+        payment_type=Invoice.PaymentTypeChoices.PREPAID,
+    )
+    InvoiceFactory(
+        challenge=challenge,
+        payment_type=Invoice.PaymentTypeChoices.COMPLIMENTARY,
+    )
+
+    mock_method = mocker.patch(
+        "grandchallenge.invoices.tasks.send_postpaid_invoice_follow_up_date_approaching_email",
+        return_value=MagicMock(),
+    )
+
+    send_post_paid_invoice_follow_up_emails()
+
+    assert mock_method.call_count == 1
+    mock_method.assert_has_calls(
+        [
+            call(postpaid_relevant),
+        ],
+    )