FEAT #513: Implement email reminders to complete risk assessments (#514)

* FEAT #513: Implement email reminders to complete risk assessments

* Add missing f-string tag

RIGS/management/commands/send_reminders.py

@@ -0,0 +1,38 @@
+import premailer
+import datetime
+
+from django.template.loader import get_template
+from django.contrib.staticfiles import finders
+from django.conf import settings
+from django.core.management.base import BaseCommand, CommandError
+from django.core.mail import EmailMultiAlternatives
+from django.utils import timezone
+from django.urls import reverse
+
+from RIGS import models
+
+
+class Command(BaseCommand):
+    help = 'Sends email reminders as required. Triggered daily through heroku-scheduler in production.'
+
+    def handle(self, *args, **options):
+        events = models.Event.objects.current_events().select_related('riskassessment')
+        for event in events:
+            earliest_time = event.earliest_time if isinstance(event.earliest_time, datetime.datetime) else timezone.make_aware(datetime.datetime.combine(event.earliest_time, datetime.time(00, 00)))
+            # 48 hours = 172800 seconds
+            if not event.cancelled and not event.dry_hire and (earliest_time - timezone.now()).total_seconds() <= 172800 and not hasattr(event, 'riskassessment'):
+                context = {
+                    "event": event,
+                    "url": "https://" + settings.DOMAIN + reverse('event_ra', kwargs={'pk': event.pk})
+                }
+                target = event.mic.email if event.mic else f"productions@{settings.DOMAIN}"
+                msg = EmailMultiAlternatives(
+                    f"{event} - Risk Assessment Incomplete",
+                    get_template("email/ra_reminder.txt").render(context),
+                    to=[target],
+                    reply_to=[f"h.s.manager@{settings.DOMAIN}"],
+                )
+                css = finders.find('css/email.css')
+                html = premailer.Premailer(get_template("email/ra_reminder.html").render(context), external_styles=css).transform()
+                msg.attach_alternative(html, 'text/html')
+                msg.send()