Update usage endpoint with billing details for orgs and services

app/dao/fact_billing_dao.py

@@ -683,3 +683,20 @@ def fetch_usage_year_for_organisation(organisation_id, year):
         service_with_usage[str(email_usage.service_id)]['emails_sent'] = email_usage.emails_sent
 
     return service_with_usage
+
+
+def fetch_billing_details_for_all_services():
+    billing_details = db.session.query(
+        Service.id.label('service_id'),
+        func.coalesce(Service.purchase_order_number, Organisation.purchase_order_number).label('purchase_order_number'),
+        func.coalesce(Service.billing_contact_names, Organisation.billing_contact_names).label('billing_contact_names'),
+        func.coalesce(
+            Service.billing_contact_email_addresses,
+            Organisation.billing_contact_email_addresses
+        ).label('billing_contact_email_addresses'),
+        func.coalesce(Service.billing_reference, Organisation.billing_reference).label('billing_reference'),
+    ).outerjoin(
+        Service.organisation
+    ).all()
+
+    return billing_details

app/platform_stats/rest.py

@@ -4,6 +4,7 @@ from flask import Blueprint, jsonify, request
 
 from app.dao.date_util import get_financial_year_for_datetime
 from app.dao.fact_billing_dao import (
+    fetch_billing_details_for_all_services,
     fetch_letter_costs_for_all_services,
     fetch_letter_line_items_for_all_services,
     fetch_sms_billing_for_all_services,
@@ -105,12 +106,24 @@ def get_usage_for_all_services():
     for service_id, breakdown in lb_by_service:
         combined[service_id]['letter_breakdown'] += (breakdown + '\n')
 
+    billing_details = fetch_billing_details_for_all_services()
+    for service in billing_details:
+        if service.service_id in combined:
+            combined[service.service_id].update({
+                    'purchase_order_number': service.purchase_order_number,
+                    'contact_names': service.billing_contact_names,
+                    'contact_email_addresses': service.billing_contact_email_addresses,
+                    'billing_reference': service.billing_reference
+                })
+
     # sorting first by name == '' means that blank orgs will be sorted last.
-    return jsonify(sorted(combined.values(), key=lambda x: (
+
+    result = sorted(combined.values(), key=lambda x: (
         x['organisation_name'] == '',
         x['organisation_name'],
         x['service_name']
-    )))
+    ))
+    return jsonify(result)
 
 
 def postage_description(postage):