changes export flow

apps/edr-freight-api/src/modules/train-scheduling/train-capacity.util.spec.ts

@@ -1,6 +1,8 @@
 import {
+  bookingCargoTons,
   bookingGrossWeightTons,
   bookingTrainLengthMeters,
+  bulkItemWagonsRequired,
   consistUsage,
   consistViolations,
   deriveTrainCapacityFromLocomotive,
@@ -30,6 +32,66 @@ describe('train-capacity.util', () => {
       cargoTons,
     }));
 
+  describe('bulkItemWagonsRequired (break-bulk PER_ITEM)', () => {
+    // cargoTotalWeightVgm carries the ITEM COUNT for PER_ITEM cargo; the real
+    // tonnage rides in bulkTotalWeightTons.
+    const breakBulk = (quantity: number, weightTons: number) => ({
+      freightType: 'BULK',
+      cargoTotalWeightVgm: quantity,
+      bulkTotalWeightTons: weightTons,
+    });
+
+    it('floors items per wagon, then ceils wagons: 400 items / 800T on 69T wagons → 12', () => {
+      // 800/400 = 2T per item; floor(69/2) = 34 per wagon; ceil(400/34) = 12.
+      expect(bulkItemWagonsRequired(breakBulk(400, 800), 69)).toBe(12);
+    });
+
+    it('needs more wagons than raw tonnage suggests when the floor loses capacity', () => {
+      // 3 items × 40T on 69T wagons: by weight ceil(120/69) = 2, but only ONE
+      // whole 40T item fits a wagon → 3 wagons.
+      expect(bulkItemWagonsRequired(breakBulk(3, 120), 69)).toBe(3);
+    });
+
+    it('charges one wagon per item when a single item outweighs a wagon', () => {
+      expect(bulkItemWagonsRequired(breakBulk(2, 200), 69)).toBe(2);
+    });
+
+    it('returns 0 for PER_TON bulk (no stored weight) and container bookings', () => {
+      expect(
+        bulkItemWagonsRequired(
+          { freightType: 'BULK', cargoTotalWeightVgm: 500, bulkTotalWeightTons: null },
+          69,
+        ),
+      ).toBe(0);
+      expect(
+        bulkItemWagonsRequired(
+          { freightType: 'CONTAINER', cargoTotalWeightVgm: 100, bulkTotalWeightTons: 100 },
+          69,
+        ),
+      ).toBe(0);
+    });
+
+    it('returns 0 on zero/invalid capacity or amounts', () => {
+      expect(bulkItemWagonsRequired(breakBulk(400, 800), 0)).toBe(0);
+      expect(bulkItemWagonsRequired(breakBulk(0, 800), 69)).toBe(0);
+      expect(bulkItemWagonsRequired(breakBulk(400, 0), 69)).toBe(0);
+    });
+  });
+
+  describe('bookingCargoTons (break-bulk weight preference)', () => {
+    it('prefers bulkTotalWeightTons over the item-count VGM column', () => {
+      expect(
+        bookingCargoTons({ cargoTotalWeightVgm: 400, bulkTotalWeightTons: 800 }),
+      ).toBe(800);
+    });
+
+    it('falls back to cargoTotalWeightVgm when no break-bulk weight is stored', () => {
+      expect(
+        bookingCargoTons({ cargoTotalWeightVgm: 500, bulkTotalWeightTons: null }),
+      ).toBe(500);
+    });
+  });
+
   describe('deriveTrainCapacityFromLocomotive', () => {
     it('derives wagon slots from train length, not a fixed 53', () => {
       const shortLoco = deriveTrainCapacityFromLocomotive(