giveme git commit message 50 char

apps/edr-freight-api/src/modules/train-scheduling/booking-batch.constants.ts

@@ -31,6 +31,19 @@ export function paymentDrainMs(): number {
   );
 }
 
+/**
+ * ISO timestamp of the end of a pay window's drain tail, for client display
+ * (the "payment processing" countdown). Null in ⇒ null out.
+ */
+export function paymentDrainEndsAtIso(
+  deadline: Date | string | null | undefined,
+): string | null {
+  if (deadline == null) return null;
+  const ms = new Date(deadline).getTime();
+  if (!Number.isFinite(ms)) return null;
+  return new Date(ms + paymentDrainMs()).toISOString();
+}
+
 /**
  * A pay window AND its drain tail have closed.
  *

apps/edr-freight-api/src/modules/train-scheduling/booking-window.gateway.ts

@@ -14,6 +14,7 @@ import { Server, Socket } from 'socket.io';
 
 import { WsAuthService } from '../notification-inbox/ws-auth.service';
 import { TrainSchedule } from '../train-schedules/entities/train-schedule.entity';
+import { paymentDrainEndsAtIso } from './booking-batch.constants';
 
 /**
  * Server → client push for booking-window state changes. Same handshake model
@@ -61,6 +62,7 @@ export class BookingWindowGateway implements OnGatewayConnection {
       windowClosesAt: schedule.windowClosesAt?.toISOString() ?? null,
       docReviewEndsAt: schedule.docReviewEndsAt?.toISOString() ?? null,
       paymentPhaseEndsAt: schedule.paymentPhaseEndsAt?.toISOString() ?? null,
+      paymentDrainEndsAt: paymentDrainEndsAtIso(schedule.paymentPhaseEndsAt),
       scheduledDepartureDate: schedule.scheduledDepartureDate?.toISOString() ?? null,
     };
     this.server.emit(BOOKING_WINDOW_WS_EVENTS.PHASE, payload);

apps/edr-freight-api/src/modules/train-scheduling/pay-window-drain.spec.ts

@@ -1,5 +1,6 @@
 import {
   DEFAULT_PAYMENT_DRAIN_MINUTES,
+  paymentDrainEndsAtIso,
   paymentDrainMs,
   payWindowLapsed,
 } from "./booking-batch.constants";
@@ -64,4 +65,16 @@ describe("payWindowLapsed — pay-window drain tail", () => {
       expect(paymentDrainMs()).toBe(DEFAULT_PAYMENT_DRAIN_MINUTES * MIN);
     }
   });
+
+  it("paymentDrainEndsAtIso reports deadline + drain, null/garbage-safe", () => {
+    expect(paymentDrainEndsAtIso(deadline)).toBe(
+      new Date(at(DEFAULT_PAYMENT_DRAIN_MINUTES * MIN)).toISOString(),
+    );
+    expect(paymentDrainEndsAtIso(deadline.toISOString())).toBe(
+      new Date(at(DEFAULT_PAYMENT_DRAIN_MINUTES * MIN)).toISOString(),
+    );
+    expect(paymentDrainEndsAtIso(null)).toBeNull();
+    expect(paymentDrainEndsAtIso(undefined)).toBeNull();
+    expect(paymentDrainEndsAtIso("not-a-date")).toBeNull();
+  });
 });

apps/edr-freight-api/src/modules/train-scheduling/train-scheduling.service.ts

@@ -153,6 +153,7 @@ import {
   DEFAULT_CONTAINER_WAGON_CAPACITY_TONS,
   DEFAULT_CONTAINER_WAGON_LENGTH_METERS,
   DEFAULT_CONTAINER_WAGON_TARE_TONS,
+  paymentDrainEndsAtIso,
 } from './booking-batch.constants';
 import { orderConsistWagons } from './consist-order.util';
 import {
@@ -6940,6 +6941,7 @@ export class TrainSchedulingService {
       windowClosesAt: r.window_closes_at,
       docReviewEndsAt: r.doc_review_ends_at,
       paymentPhaseEndsAt: r.payment_phase_ends_at,
+      paymentDrainEndsAt: paymentDrainEndsAtIso(r.payment_phase_ends_at),
       bookingWindowStatus: r.booking_window_status,
       bookingCycleNo: r.booking_cycle_no,
       departureDate: r.scheduled_departure_date,