fix issue and add consolidation

apps/edr-freight-api/src/modules/train-scheduling/utils/wagon-plan.util.ts

@@ -200,16 +200,14 @@ export function buildBulkWagonPlan(
   );
   const cappedTonSlots = cappedTonSlotsByBooking.reduce((sum, n) => sum + n, 0);
 
-  const totalWeight = roundTons(
-    bookings.reduce(
-      (sum, b, i) =>
-        itemSlotsByBooking[i] > 0 || cappedTonSlotsByBooking[i] > 0
-          ? sum
-          : sum + Number(b.cargoTotalWeightVgm ?? 0),
-      0,
-    ),
-  );
-  const tonSlots = totalWeight > 0 ? Math.ceil(totalWeight / capacity) : 0;
+  // One bulk booking per wagon — bookings never pool tonnage on a shared
+  // wagon, so each uncapped booking sizes its own wagons (ceil per booking,
+  // not over the pooled total).
+  const tonSlots = bookings.reduce((sum, b, i) => {
+    if (itemSlotsByBooking[i] > 0 || cappedTonSlotsByBooking[i] > 0) return sum;
+    const weight = roundTons(Number(b.cargoTotalWeightVgm ?? 0));
+    return weight > 0 ? sum + Math.ceil(weight / capacity) : sum;
+  }, 0);
   const slots = Math.max(1, tonSlots + itemSlots + cappedTonSlots);
 
   const basePlan: WagonPlanSlot[] = Array.from({ length: slots }, (_, index) => ({
@@ -374,13 +372,12 @@ function allocateBookingsToSlots(
 
       if (booking.remainingWeightTons <= 0) {
         bookingIndex += 1;
-      } else if (allocatedWeightTons >= takeCap) {
-        // The cap stopped this wagon short of its rating and the booking has
-        // more to load. The leftover room is NOT free: `buildBulkWagonPlan`
-        // already reserved a wagon for the rest, so backfilling another booking
-        // here would double-book the consist. Close the wagon.
-        break;
       }
+      // One bulk booking per wagon: a wagon carrying bulk takes nothing else —
+      // never a second booking's cargo. `buildBulkWagonPlan` sized the slots
+      // per booking, so leftover room on this wagon is not free capacity.
+      // Close the wagon after its single allocation.
+      break;
     }
 
     return { ...slot, assignedWeightTons, allocations };
@@ -504,6 +501,26 @@ export function sumWagonsRequired(booking: Booking, wagonPlan?: WagonPlanSlot[])
   );
 }
 
+/**
+ * One wagon carries one kind of cargo: a slot with a BULK allocation holds
+ * nothing else — no container beside it and no second bulk booking. Container
+ * allocations may still share a wagon with each other (TEU rules apply).
+ */
+export function validateWagonCargoExclusivity(wagonPlan: WagonPlanSlot[]): string[] {
+  const violations: string[] = [];
+  for (const slot of wagonPlan) {
+    const hasBulk = slot.allocations.some(
+      (a) => a.loadType === AllocationLoadType.Bulk,
+    );
+    if (hasBulk && slot.allocations.length > 1) {
+      violations.push(
+        `Wagon #${slot.sequenceNo} mixes bulk with other cargo — a wagon carrying bulk takes that one load only`,
+      );
+    }
+  }
+  return violations;
+}
+
 export function validateBulkWagonSlotWeights(wagonPlan: WagonPlanSlot[]): string[] {
   const violations: string[] = [];
   for (const slot of wagonPlan.filter((s) => s.slotLoadType === 'BULK')) {
@@ -547,6 +564,7 @@ export function validateTrainLimits(
   );
 
   violations.push(...validateBulkWagonSlotWeights(wagonPlan));
+  violations.push(...validateWagonCargoExclusivity(wagonPlan));
 
   return violations;
 }