fix issue

apps/edr-freight-api/src/modules/bookings/booking-wagon-cancellation.service.spec.ts

@@ -1,6 +1,10 @@
 import { BadRequestException } from '@nestjs/common';
 
 import { BookingWagonCancellationService } from './booking-wagon-cancellation.service';
+import {
+  bulkTonWagonsRequired,
+  bulkTonsPerWagonFor,
+} from '../train-scheduling/train-capacity.util';
 
 /**
  * Sizing of a bulk quantity cut (no DB touched on this branch): a whole-booking
@@ -107,3 +111,48 @@ describe('BookingWagonCancellationService.rebook (odd-20ft consolidation)', () =
     ).rejects.toThrow(/already shares a wagon/i);
   });
 });
+
+/**
+ * A NUMBER_OF_WAGONS booking pins its count in `bulkRequestedWagons`, and
+ * bulkTonWagonsRequired honours that verbatim. Partial cancel must shrink it
+ * alongside wagonsRequired/cargoTotalWeightVgm — left stale, the booking
+ * re-inflates to its pre-cancel count on the next allocation and each wagon
+ * carries tons / stale-count instead of the real even share.
+ */
+describe('partial cancel of a NUMBER_OF_WAGONS bulk booking', () => {
+  // 980T over 14 wagons (70T each), 2 wagons cancelled.
+  const before = { freightType: 'BULK', cargoTotalWeightVgm: 980, bulkRequestedWagons: 14 };
+  const droppedWeight = 140;
+  const wagonsCancelled = 2;
+
+  // The decrement applied in applyPaidCut's booking update.
+  const after = {
+    ...before,
+    cargoTotalWeightVgm: before.cargoTotalWeightVgm - droppedWeight,
+    bulkRequestedWagons: Math.max(
+      0,
+      Math.floor(before.bulkRequestedWagons - wagonsCancelled),
+    ),
+  };
+
+  it('reallocates at the reduced count, not the pre-cancel one', () => {
+    expect(bulkTonWagonsRequired(before, undefined, 'nw5', 70)).toBe(14);
+    expect(bulkTonWagonsRequired(after, undefined, 'nw5', 70)).toBe(12);
+  });
+
+  it('keeps tons-per-wagon at the real even share', () => {
+    // Stale count would spread 840T over 14 wagons → 60T each.
+    expect(bulkTonsPerWagonFor(after, undefined, 'nw5', 70)).toBe(70);
+  });
+
+  it('cancelling every wagon leaves no requested count behind', () => {
+    const all = Math.max(0, Math.floor(before.bulkRequestedWagons - 14));
+    expect(all).toBe(0);
+    expect(bulkTonWagonsRequired(
+      { ...before, cargoTotalWeightVgm: 0, bulkRequestedWagons: all },
+      undefined,
+      'nw5',
+      70,
+    )).toBe(0);
+  });
+});

apps/edr-freight-api/src/modules/bookings/booking-wagon-cancellation.service.ts

@@ -704,8 +704,21 @@ export class BookingWagonCancellationService {
         Number(booking.wagonsRequired ?? 0) - Number(row.wagonsCancelled),
       );
       const isFull = wagonsLeft <= 0;
+      // NUMBER_OF_WAGONS bookings pin their count in bulkRequestedWagons, which
+      // bulkTonWagonsRequired honours verbatim. Left stale it re-inflates the
+      // booking to its pre-cancel count on the next allocation (and shrinks
+      // tons-per-wagon to tons / stale-count), so shrink it with the cut.
+      const requestedWagonsLeft = booking.bulkRequestedWagons
+        ? Math.max(
+            0,
+            Math.floor(Number(booking.bulkRequestedWagons) - Number(row.wagonsCancelled)),
+          )
+        : null;
       await manager.getRepository(Booking).update(booking.id, {
         wagonsRequired: Math.max(0, wagonsLeft),
+        ...(requestedWagonsLeft !== null
+          ? { bulkRequestedWagons: requestedWagonsLeft }
+          : {}),
         cargoTotalWeightVgm: Math.max(
           0,
           round3(Number(booking.cargoTotalWeightVgm) - droppedWeight),