move monthly notification stats from notification history to ft tables

it now uses the ft_notification_status table - nice and quick. if you
ask for the current tax year it'll top up the data with numbers from
the notification table.

the data is in exactly the same shape as the old endpoint - no changes
to the admin app are necessary

app/dao/fact_notification_status_dao.py

@@ -6,7 +6,7 @@ from sqlalchemy.dialects.postgresql import insert
 
 from app import db
 from app.models import Notification, NotificationHistory, FactNotificationStatus
-from app.utils import convert_bst_to_utc
+from app.utils import convert_bst_to_utc, get_london_midnight_in_utc, get_london_month_from_utc_column
 
 
 def fetch_notification_status_for_day(process_day, service_id=None):
@@ -73,3 +73,41 @@ def update_fact_notification_status(data, process_day):
         )
         db.session.connection().execute(stmt)
         db.session.commit()
+
+
+def fetch_notification_status_for_service_by_month(start_date, end_date, service_id):
+    return db.session.query(
+        func.date_trunc('month', FactNotificationStatus.bst_date).label('month'),
+        FactNotificationStatus.notification_type,
+        FactNotificationStatus.notification_status,
+        func.sum(FactNotificationStatus.notification_count).label('count')
+    ).filter(
+        FactNotificationStatus.service_id == service_id,
+        FactNotificationStatus.bst_date >= start_date,
+        FactNotificationStatus.bst_date < end_date,
+    ).group_by(
+        func.date_trunc('month', FactNotificationStatus.bst_date).label('month'),
+        FactNotificationStatus.notification_type,
+        FactNotificationStatus.notification_status
+    ).all()
+
+
+def fetch_notification_status_for_service_for_day(bst_day, service_id):
+    return db.session.query(
+        # return current month as a datetime so the data has the same shape as the ft_notification_status query
+        get_london_month_from_utc_column(func.current_date()),
+        Notification.notification_type,
+        Notification.status,
+        func.count()
+    ).filter(
+        Notification.created_at >= get_london_midnight_in_utc(bst_day),
+        Notification.created_at < get_london_midnight_in_utc(bst_day + timedelta(days=1)),
+        Notification.service_id == service_id
+    ).group_by(
+        Notification.template_id,
+        Notification.service_id,
+        'job_id',
+        Notification.notification_type,
+        Notification.key_type,
+        Notification.status
+    ).all()