support: Implement setting a current plan end date for Cloud support.

Prep for implementing fixed-price plan offers in Cloud support view.

corporate/lib/stripe.py

@@ -1612,7 +1612,9 @@ class BillingSession(ABC):
                         "property": "next_invoice_date",
                     }
                     plan.next_invoice_date = new_end_date
-                # Currently, we send a reminder email 2 months before the end date.
+                # We send a reminder email 2 months before the end date of
+                # remote server and remote realm fixed-price plans so that
+                # billing support can follow-up about continuing service.
                 # Reset it when we are extending the end_date.
                 reminder_to_review_plan_email_sent_changed_extra_data = None
                 if (
@@ -1659,9 +1661,7 @@ class BillingSession(ABC):
                     )
 
                 return f"Current plan for {self.billing_entity_display_name} updated to end on {end_date_string}."
-        raise SupportRequestError(
+        raise SupportRequestError(f"No current plan for {self.billing_entity_display_name}.")
-            f"No current plan for {self.billing_entity_display_name}."
-        )  # nocoverage
 
     def generate_stripe_invoice(
         self,

corporate/tests/test_support_views.py

@@ -1513,6 +1513,62 @@ class TestSupportEndpoint(ZulipTestCase):
         )
         self.assert_length(messages, 1)
 
+    def test_update_current_plan_end_date(self) -> None:
+        lear_realm = get_realm("lear")
+        customer = get_customer_by_realm(lear_realm)
+        assert customer is None
+
+        iago = self.example_user("iago")
+        self.login_user(iago)
+
+        result = self.client_post(
+            "/activity/support",
+            {
+                "realm_id": f"{lear_realm.id}",
+                "plan_end_date": "2020-01-01",
+            },
+        )
+        self.assert_in_success_response(
+            ["Cannot update current plan for lear to end on 2020-01-01."],
+            result,
+        )
+
+        result = self.client_post(
+            "/activity/support",
+            {
+                "realm_id": f"{lear_realm.id}",
+                "plan_end_date": "2050-03-01",
+            },
+        )
+        self.assert_in_success_response(
+            ["No current plan for lear."],
+            result,
+        )
+
+        customer = self.create_customer_and_plan(lear_realm, True)
+        assert customer is not None
+        current_plan = get_current_plan_by_customer(customer)
+        assert current_plan is not None
+        self.assertIsNone(current_plan.end_date)
+        next_invoice_date = current_plan.next_invoice_date
+        assert next_invoice_date is not None
+
+        result = self.client_post(
+            "/activity/support",
+            {
+                "realm_id": f"{lear_realm.id}",
+                "plan_end_date": "2050-03-01",
+            },
+        )
+        self.assert_in_success_response(
+            ["Current plan for lear updated to end on 2050-03-01."],
+            result,
+        )
+
+        current_plan.refresh_from_db()
+        self.assertEqual(current_plan.end_date, datetime(2050, 3, 1, tzinfo=timezone.utc))
+        self.assertEqual(current_plan.next_invoice_date, next_invoice_date)
+
     def test_approve_sponsorship_deactivated_realm(self) -> None:
         support_admin = self.example_user("iago")
         with self.settings(BILLING_ENABLED=True):

corporate/views/support.py

@@ -419,6 +419,8 @@ def support(
     query: Annotated[str | None, ApiParamConfig("q")] = None,
     org_type: Json[NonNegativeInt] | None = None,
     max_invites: Json[NonNegativeInt] | None = None,
+    plan_end_date: Annotated[str, AfterValidator(lambda x: check_date("plan_end_date", x))]
+    | None = None,
 ) -> HttpResponse:
     from corporate.lib.stripe import (
         RealmBillingSession,
@@ -482,6 +484,11 @@ def support(
             )
             if modify_plan == "upgrade_plan_tier":
                 support_view_request["new_plan_tier"] = CustomerPlan.TIER_CLOUD_PLUS
+        elif plan_end_date is not None:
+            support_view_request = SupportViewRequest(
+                support_type=SupportType.update_plan_end_date,
+                plan_end_date=plan_end_date,
+            )
         elif plan_type is not None:
             current_plan_type = realm.plan_type
             do_change_realm_plan_type(realm, plan_type, acting_user=acting_user)

templates/corporate/support/current_plan_forms_support.html

@@ -9,7 +9,7 @@
     <button type="submit" class="support-submit-button">Update</button>
 </form>
 
-{% if current_plan.status == current_plan.ACTIVE and remote_support_view %}
+{% if current_plan.status == current_plan.ACTIVE %}
 <form method="POST" class="support-form">
     <b>Plan end date</b><br />
     {{ csrf_input }}