Added a new endpoint to return the last used date for a template.

The existing endpoint returned a whole notification for the last time the template was used. But this only takes into account data in the last week. This new methods allows us to be specific about when the template was last used if ever but looking into the ft_notification_status table as well.

app/dao/notifications_dao.py

@@ -30,6 +30,7 @@ from app.dao.dao_utils import transactional
 from app.errors import InvalidRequest
 from app.letters.utils import get_letter_pdf_filename
 from app.models import (
+    FactNotificationStatus,
     Notification,
     NotificationHistory,
     ProviderDetails,
@@ -70,6 +71,37 @@ def dao_get_last_template_usage(template_id, template_type, service_id):
     ).first()
 
 
+@statsd(namespace="dao")
+def dao_get_last_date_template_was_used(template_id, template_type, service_id):
+    last_date = db.session.query(
+        functions.max(FactNotificationStatus.bst_date)
+    ).filter(
+        FactNotificationStatus.template_id == template_id,
+        FactNotificationStatus.key_type != KEY_TYPE_TEST
+    ).scalar()
+
+    last_date_from_notifications = db.session.query(
+        functions.max(Notification.created_at)
+    ).filter(
+        Notification.service_id == service_id,
+        Notification.notification_type == template_type,
+        Notification.template_id == template_id,
+        Notification.key_type != KEY_TYPE_TEST
+    ).scalar()
+
+    if last_date and last_date_from_notifications:
+        if datetime.combine(last_date, datetime.utcnow().min.time()) >= last_date_from_notifications:
+            return last_date
+        else:
+            return last_date_from_notifications
+    elif not last_date:
+        return last_date_from_notifications
+    elif not last_date_from_notifications:
+        return last_date
+    else:
+        return None
+
+
 @statsd(namespace="dao")
 @transactional
 def dao_create_notification(notification):

app/template_statistics/rest.py

@@ -1,5 +1,7 @@
 from flask import Blueprint, jsonify, request
-from app.dao.notifications_dao import dao_get_last_template_usage
+
+from app import DATETIME_FORMAT
+from app.dao.notifications_dao import dao_get_last_template_usage, dao_get_last_date_template_was_used
 from app.dao.templates_dao import dao_get_template_by_id_and_service_id
 from app.dao.fact_notification_status_dao import fetch_notification_status_for_service_for_today_and_7_previous_days
 
@@ -52,3 +54,14 @@ def get_template_statistics_for_template_id(service_id, template_id):
         data = notification_with_template_schema.dump(notification).data
 
     return jsonify(data=data)
+
+
+@template_statistics.route('/last-used/<uuid:template_id>')
+def get_last_used_datetime_for_template(service_id, template_id):
+    template = dao_get_template_by_id_and_service_id(template_id, service_id)
+
+    last_date_used = dao_get_last_date_template_was_used(template_id=template_id,
+                                                         template_type=template.template_type,
+                                                         service_id=service_id)
+
+    return jsonify(last_date_used=last_date_used.strftime(DATETIME_FORMAT))