Created new queries to return the rate with the sum of billable units for the year totals.

Once we have the new columns in notifications table, the query will need to include the rate multiplier and if the number is international.
The monthly billing query will be built next.

app/dao/notification_usage_dao.py

@@ -0,0 +1,69 @@
+from decimal import Decimal
+
+from sqlalchemy import func
+
+from app import db
+from app.dao.date_util import get_financial_year
+from app.models import (NotificationHistory,
+                        Rate,
+                        NOTIFICATION_STATUS_TYPES_BILLABLE,
+                        KEY_TYPE_TEST,
+                        SMS_TYPE,
+                        EMAIL_TYPE)
+from app.statsd_decorators import statsd
+
+
+@statsd(namespace="dao")
+def get_yearly_billing_data(service_id, year):
+    start_date, end_date = get_financial_year(year)
+    rates = get_rates_for_year(start_date, end_date, SMS_TYPE)
+
+    result = []
+    for r, n in zip(rates, rates[1:]):
+        result.append(
+            sms_billing_data_query(str(r.rate), service_id, r.valid_from, n.valid_from))
+
+    result.append(sms_billing_data_query(str(rates[-1].rate), service_id, rates[-1].valid_from, end_date))
+
+    result.append(email_billing_data_query(service_id, start_date, end_date))
+
+    return result
+
+
+def billing_data_filter(notification_type, start_date, end_date, service_id):
+    return [NotificationHistory.notification_type == notification_type,
+            NotificationHistory.created_at >= start_date,
+            NotificationHistory.created_at < end_date,
+            NotificationHistory.service_id == service_id,
+            NotificationHistory.status.in_(NOTIFICATION_STATUS_TYPES_BILLABLE),
+            NotificationHistory.key_type != KEY_TYPE_TEST
+            ]
+
+
+def email_billing_data_query(service_id, start_date, end_date):
+    result = db.session.query(func.count(NotificationHistory.id),
+                              NotificationHistory.notification_type,
+                              "0"
+                              ).filter(*billing_data_filter(EMAIL_TYPE, start_date, end_date, service_id)
+                                       ).group_by(NotificationHistory.notification_type).first()
+    if not result:
+        return 0, EMAIL_TYPE, Decimal("0")
+    else:
+        return result
+
+
+def sms_billing_data_query(rate, service_id, start_date, end_date):
+    result = db.session.query(func.sum(NotificationHistory.billable_units),
+                              NotificationHistory.notification_type,
+                              rate
+                              ).filter(*billing_data_filter(SMS_TYPE, start_date, end_date, service_id)
+                                       ).group_by(NotificationHistory.notification_type).first()
+    if not result:
+        return 0, SMS_TYPE, Decimal("0")
+    else:
+        return result
+
+
+def get_rates_for_year(start_date, end_date, notification_type):
+    return Rate.query.filter(Rate.valid_from >= start_date, Rate.valid_from < end_date,
+                             Rate.notification_type == notification_type).order_by(Rate.valid_from).all()