supporters: Add sustainer confirmation email

conservancy/supporters/mail.py

@@ -0,0 +1,17 @@
+from django.core.mail import EmailMessage
+from django.template.loader import render_to_string
+
+
+def make_stripe_email(order) -> EmailMessage:
+    subject = 'Thanks for your sustainer payment!'
+    email_body = render_to_string(
+        'supporters/mail/sustainer_thanks.txt',
+        {'order': order},
+    ).strip()
+    message = EmailMessage(
+        subject,
+        email_body,
+        'Software Freedom Conservancy <sustainers@sfconservancy.org>',
+        [order.email],
+    )
+    return message

conservancy/supporters/templates/supporters/mail/sustainer_thanks.txt

@@ -0,0 +1,18 @@
+Hi {{ order.name }},
+
+Thanks so much for being a sustainer! Your support is what makes our work possible.
+
+Order: #{{ order.id }}
+Payment: ${{ order.amount }}{% if order.recurring %} {{ order.get_recurring_display }}{% endif %}
+Acknowledge me on the list of sustainers: {{ order.acknowledge_publicly|yesno }}
+Add me to the announcements email list: {{ order.add_to_mailing_list|yesno }}
+T-shirt: {{ order.get_tshirt_size_display }}{% if order.tshirt_size %}
+Postal address:
+{{ order.street }}
+{{ order.city }} {{ order.state }} {{ order.zip_code }}
+{{ order.country }}{% endif %}
+{% if order.recurring == 'month' and order.tshirt_size %}
+Please note that you may not receive the T-shirt until you've paid at least $60.{% endif %}
+
+Kind regards,
+Software Freedom Conservancy

conservancy/supporters/views.py

@@ -8,7 +8,7 @@ from django.utils import timezone
 import stripe
 
 from .. import ParameterValidator
-from . import forms
+from . import forms, mail
 from .models import Supporter, SustainerOrder
 
 logger = logging.getLogger(__name__)
@@ -138,6 +138,8 @@ def fulfill_checkout(session_id):
                 order.payment_id = checkout_session['invoice']['payment_intent']
             order.save()
             logger.info(f'Marked sustainer order {order.id} (order.email) as paid')
+            email = mail.make_stripe_email(order)
+            email.send()
         except SustainerOrder.DoesNotExist:
             logger.info('No action')