fix: Handle edge case of past invoice older than last period

Author: calvin-codecov

services/billing.py

@@ -2,6 +2,7 @@
 import re
 from abc import ABC, abstractmethod
 from datetime import datetime
+from dateutil.relativedelta import relativedelta
 
 import stripe
 from django.conf import settings
@@ -164,18 +165,25 @@ def delete_subscription(self, owner: Owner):
             )
             stripe.SubscriptionSchedule.release(subscription_schedule_id)
 
-        # we give a auto-refund grace period of 24 hours for a monthly subscription or 72 hours for a yearly subscription
-        current_subscription_timestamp = subscription["current_period_start"]
-        difference = datetime.now() - datetime.fromtimestamp(current_subscription_timestamp)
+        # we give an auto-refund grace period of 24 hours for a monthly subscription or 72 hours for a yearly subscription
+        # current_subscription_timestamp = subscription["current_period_start"]
+        current_subscription_datetime = datetime.fromtimestamp(subscription["current_period_start"])
+        differenceFromNow = datetime.now() - current_subscription_datetime
+
         subscription_plan_interval = subscription.plan.interval if subscription.plan is not None else None
-        should_refund_grace_period = (subscription_plan_interval == "month" and difference.days < 1) or (subscription_plan_interval == "year" and difference.days < 3)
-        if should_refund_grace_period:
+        within_refund_grace_period = (subscription_plan_interval == "month" and differenceFromNow.days < 1) or (subscription_plan_interval == "year" and differenceFromNow.days < 3)
+        if within_refund_grace_period:
             stripe.Subscription.cancel(owner.stripe_subscription_id)
 
             invoices_list = stripe.Invoice.list(subscription=owner.stripe_subscription_id, status="paid")
             created_refund = False
+            # there could be multiple invoices that need to be refunded such as if the user increased seats within the grace period
             for invoice in invoices_list["data"]:
-                if invoice["charge"] is not None and invoice["amount_remaining"] == 0 and invoice["created"] < current_subscription_timestamp:
+                start_of_last_period = current_subscription_datetime - relativedelta(months=1) if subscription_plan_interval == "month" else current_subscription_datetime - relativedelta(years=1)
+
+                # refund if the invoice has a charge, it has been fully paid, the creation time was before the start of the current subscription's start and the creation time was after the start of the last period
+                invoice_created_datetime = datetime.fromtimestamp(invoice["created"])
+                if invoice["charge"] is not None and invoice["amount_remaining"] == 0 and invoice_created_datetime < current_subscription_datetime and invoice_created_datetime >= start_of_last_period:
                     stripe.Refund.create(invoice["charge"])
                     created_refund = True
             if created_refund == True:

services/tests/test_billing.py

@@ -1,10 +1,10 @@
 import json
 from unittest.mock import MagicMock, patch
-from freezegun import freeze_time
 
 import requests
 from django.conf import settings
 from django.test import TestCase
+from freezegun import freeze_time
 from stripe import InvalidRequestError
 
 from codecov_auth.models import Service
@@ -291,8 +291,8 @@ def test_delete_subscription_without_schedule_modifies_subscription_to_delete_at
         )
         subscription_params = {
             "schedule_id": stripe_schedule_id,
-            "start_date": 1639628096,
-            "end_date": 1644107871,
+            "start_date": 1489799420,
+            "end_date": 1492477820,
             "quantity": 10,
             "name": plan,
             "id": 215,
@@ -311,7 +311,7 @@ def test_delete_subscription_without_schedule_modifies_subscription_to_delete_at
         assert owner.plan_activated_users == [4, 6, 3]
         assert owner.plan_user_count == 9
 
-    @freeze_time("2021-12-22T00:00:00")
+    @freeze_time("2017-03-22T00:00:00")
     @patch("services.billing.stripe.Refund.create")
     @patch("services.billing.stripe.Subscription.modify")
     @patch("services.billing.stripe.Subscription.retrieve")
@@ -330,8 +330,8 @@ def test_delete_subscription_with_schedule_releases_schedule_and_cancels_subscri
         )
         subscription_params = {
             "schedule_id": stripe_schedule_id,
-            "start_date": 1639628096,
-            "end_date": 1644107871,
+            "start_date": 1489799420,
+            "end_date": 1492477820,
             "quantity": 10,
             "name": plan,
             "id": 215,
@@ -352,7 +352,7 @@ def test_delete_subscription_with_schedule_releases_schedule_and_cancels_subscri
         assert owner.plan_activated_users == [4, 6, 3]
         assert owner.plan_user_count == 9
 
-    @freeze_time("2021-12-17T00:00:00")
+    @freeze_time("2017-03-18T00:00:00")
     @patch("services.billing.stripe.Subscription.modify")
     @patch("services.billing.stripe.Customer.modify")
     @patch("services.billing.stripe.Refund.create")
@@ -377,8 +377,8 @@ def test_delete_subscription_with_schedule_releases_schedule_and_cancels_subscri
         )
         subscription_params = {
             "schedule_id": stripe_schedule_id,
-            "start_date": 1639628096,
-            "end_date": 1644107871,
+            "start_date": 1489799420,
+            "end_date": 1492477820,
             "quantity": 10,
             "name": plan,
             "id": 215,
@@ -405,7 +405,7 @@ def test_delete_subscription_with_schedule_releases_schedule_and_cancels_subscri
         assert owner.plan_activated_users == [4, 6, 3]
         assert owner.plan_user_count == 9
 
-    @freeze_time("2021-12-19T00:00:00")
+    @freeze_time("2017-03-19T00:00:00")
     @patch("services.billing.stripe.Subscription.modify")
     @patch("services.billing.stripe.Customer.modify")
     @patch("services.billing.stripe.Refund.create")
@@ -430,8 +430,8 @@ def test_delete_subscription_with_schedule_releases_schedule_and_cancels_subscri
         )
         subscription_params = {
             "schedule_id": stripe_schedule_id,
-            "start_date": 1639628096,
-            "end_date": 1644107871,
+            "start_date": 1489799420,
+            "end_date": 1492477820,
             "quantity": 10,
             "name": plan,
             "id": 215,