Fix billable units

There was a situation where the SMS was sent, the request timed out we got a 503 so the notification was put on the retry queue. However, the provider got the notification and sent the message. This means we didn't set the billable_units on the notification and the service will not be billed.
This PR is to fix the notifications that we can accurrately update.

app/commands.py

@@ -9,6 +9,7 @@ import flask
 import itertools
 from click_datetime import Datetime as click_dt
 from flask import current_app, json
+from notifications_utils.template import SMSMessageTemplate
 from psycopg2._psycopg import IntegrityError
 from sqlalchemy.orm.exc import NoResultFound
 from notifications_utils.statsd_decorators import statsd
@@ -26,6 +27,7 @@ from app.dao.fact_billing_dao import (
     get_service_ids_that_need_billing_populated,
     update_fact_billing,
 )
+from app.dao.notifications_dao import dao_update_notification
 from app.dao.organisation_dao import dao_get_organisation_by_email_address, dao_add_service_to_organisation
 
 from app.dao.provider_rates_dao import create_provider_rates as dao_create_provider_rates
@@ -36,8 +38,9 @@ from app.dao.services_dao import (
     dao_fetch_service_by_id,
     dao_update_service
 )
+from app.dao.templates_dao import dao_get_template_by_id
 from app.dao.users_dao import delete_model_user, delete_user_verify_codes, get_user_by_email
-from app.models import PROVIDERS, User, Notification, Organisation, Domain, Service
+from app.models import PROVIDERS, User, Notification, Organisation, Domain, Service, KEY_TYPE_NORMAL
 from app.performance_platform.processing_time import send_processing_time_for_start_and_end
 from app.utils import get_london_midnight_in_utc, get_midnight_for_day_before
 
@@ -842,3 +845,31 @@ def populate_go_live(file_name):
             service.go_live_user = go_live_user
             service.go_live_at = go_live_date
             dao_update_service(service)
+
+
+@notify_command(name='fix-billable-units')
+def fix_billable_units():
+    query = Notification.query.filter(
+        Notification.sent_at == None,  # noqa
+        Notification.billable_units == 0,
+        Notification.key_type == KEY_TYPE_NORMAL
+    )
+
+    for notification in query.all():
+        template_model = dao_get_template_by_id(notification.template_id, notification.template_version)
+
+        template = SMSMessageTemplate(
+            template_model.__dict__,
+            values=notification.personalisation,
+            prefix=notification.service.name,
+            show_prefix=notification.service.prefix_sms,
+        )
+        print("Updating notification: {} with {} billable_units".format(notification.id, template.fragment_count))
+
+        Notification.query.filter(
+            Notification.id == notification.id
+        ).update(
+            {"billable_units": template.fragment_count}
+        )
+
+    print("End fix_billable_units")