Add a management command to clean up lingering tutorial streams.

We now clean up the stream subscription in more places, but some
historical tutorial streams are still around and if an error or page
reload happens during the tutorial it'll stick around.

(imported from commit 8cf0ebda26bf752c1a23296a4ba85d194bbb3004)

zephyr/management/commands/delete_tutorial_streams.py

@@ -0,0 +1,50 @@
+from django.core.management.base import BaseCommand
+from zephyr.models import UserProfile, Subscription, Recipient, Message, Stream
+from django.db.models import Q
+
+import datetime
+import pytz
+from optparse import make_option
+
+class Command(BaseCommand):
+    help = """Delete all inactive tutorial stream subscriptions."""
+
+    option_list = BaseCommand.option_list + (
+        make_option('-f', '--for-real',
+                    dest='for_real',
+                    action='store_true',
+                    default=False,
+                    help="Actually deactive subscriptions. Default is a dry run."),
+        )
+
+    def has_sent_to(self, user_profile, recipient):
+        return Message.objects.filter(sender=user_profile, recipient=recipient).count() != 0
+
+    def handle(self, **options):
+        possible_tutorial_streams = Stream.objects.filter(Q(name__startswith='tutorial-'))
+
+        tutorial_bot = UserProfile.objects.get(user__email="humbug+tutorial@humbughq.com")
+
+        for stream in possible_tutorial_streams:
+            recipient = Recipient.objects.get(type=Recipient.STREAM, type_id=stream.id)
+            subscribers = Subscription.objects.filter(recipient=recipient, active=True)
+            if ((subscribers.count() == 1) and self.has_sent_to(tutorial_bot, recipient)):
+                # This is a tutorial stream.
+                most_recent_message = Message.objects.filter(
+                    recipient=recipient).latest("pub_date")
+                # This cutoff must be more generous than the tutorial bot cutoff
+                # in the client code.
+                cutoff = datetime.datetime.now(tz=pytz.utc) - datetime.timedelta(hours=2)
+
+                if most_recent_message.pub_date < cutoff:
+                    # The tutorial has expired, so delete the stream.
+                    print stream.name, most_recent_message.pub_date
+                    if options["for_real"]:
+                        tutorial_user = subscribers[0]
+                        tutorial_user.active = False
+                        tutorial_user.save()
+
+        if options["for_real"]:
+            print "Subscriptions deactivated."
+        else:
+            print "This was a dry run. Pass -f to actually deactivate."