fix nightly ft stats tables task to respect BST

the create_nightly_notification_status task runs at 00:30am UK time,
however this means that in summer datetime.today() will return the
wrong date as the server (which runs on UTC) will run the task at
23:30 (populating the wrong row in the table).

fix this to use nice tz aware functions

app/celery/reporting_tasks.py

@@ -10,6 +10,7 @@ from app.dao.fact_billing_dao import (
     update_fact_billing
 )
 from app.dao.fact_notification_status_dao import fetch_notification_status_for_day, update_fact_notification_status
+from app.utils import convert_utc_to_bst
 
 
 @notify_celery.task(name="create-nightly-billing")
@@ -19,10 +20,10 @@ def create_nightly_billing(day_start=None):
     # day_start is a datetime.date() object. e.g.
     # up to 10 days of data counting back from day_start is consolidated
     if day_start is None:
-        day_start = datetime.today() - timedelta(days=1)
+        day_start = convert_utc_to_bst(datetime.utcnow()).date() - timedelta(days=1)
     else:
         # When calling the task its a string in the format of "YYYY-MM-DD"
-        day_start = datetime.strptime(day_start, "%Y-%m-%d")
+        day_start = datetime.strptime(day_start, "%Y-%m-%d").date()
     for i in range(0, 10):
         process_day = day_start - timedelta(days=i)
 
@@ -42,10 +43,10 @@ def create_nightly_notification_status(day_start=None):
     # day_start is a datetime.date() object. e.g.
     # 4 days of data counting back from day_start is consolidated
     if day_start is None:
-        day_start = datetime.today() - timedelta(days=1)
+        day_start = convert_utc_to_bst(datetime.utcnow()).date() - timedelta(days=1)
     else:
         # When calling the task its a string in the format of "YYYY-MM-DD"
-        day_start = datetime.strptime(day_start, "%Y-%m-%d")
+        day_start = datetime.strptime(day_start, "%Y-%m-%d").date()
     for i in range(0, 4):
         process_day = day_start - timedelta(days=i)
 

app/dao/fact_billing_dao.py

@@ -287,7 +287,7 @@ def update_fact_billing(data, process_day):
 
 def create_billing_record(data, rate, process_day):
     billing_record = FactBilling(
-        bst_date=process_day.date(),
+        bst_date=process_day,
         template_id=data.template_id,
         service_id=data.service_id,
         notification_type=data.notification_type,

app/dao/fact_notification_status_dao.py

@@ -54,11 +54,11 @@ def fetch_notification_status_for_day(process_day, service_id=None):
 def update_fact_notification_status(data, process_day):
     table = FactNotificationStatus.__table__
     FactNotificationStatus.query.filter(
-        FactNotificationStatus.bst_date == process_day.date()
+        FactNotificationStatus.bst_date == process_day
     ).delete()
     for row in data:
         stmt = insert(table).values(
-            bst_date=process_day.date(),
+            bst_date=process_day,
             template_id=row.template_id,
             service_id=row.service_id,
             job_id=row.job_id,