Query ft_billing aggregate for a month

app/dao/fact_billing_dao.py

@@ -0,0 +1,34 @@
+from sqlalchemy import func
+
+from app import db
+from app.dao.date_util import get_month_start_and_end_date_in_utc
+from app.models import FactBilling
+from app.utils import convert_utc_to_bst
+
+
+def fetch_annual_billing_by_month(service_id, billing_month, notification_type):
+    billing_month_in_bst = convert_utc_to_bst(billing_month)
+    start_date, end_date = get_month_start_and_end_date_in_utc(billing_month_in_bst)
+
+    monthly_data = db.session.query(
+        func.sum(FactBilling.notifications_sent).label('notifications_sent'),
+        func.sum(FactBilling.billable_units).label('billing_units'),
+        FactBilling.service_id,
+        FactBilling.notification_type,
+        FactBilling.rate,
+        FactBilling.rate_multiplier,
+        FactBilling.international
+    ).filter(
+        FactBilling.notification_type == notification_type,
+        FactBilling.service_id == service_id,
+        FactBilling.bst_date >= start_date,
+        FactBilling.bst_date <= end_date
+    ).group_by(
+        FactBilling.service_id,
+        FactBilling.notification_type,
+        FactBilling.rate,
+        FactBilling.rate_multiplier,
+        FactBilling.international
+    ).all()
+
+    return monthly_data, start_date