add lashing surcharge for cargo types with hasLashing flag

add lashing surcharge for cargo types with hasLashing flag

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

@@ -340,6 +340,31 @@ export function planWagonsWithStock(params: {
   };
 }
 
+/**
+ * Reverse the wagon ORDER of a built plan when a schedule opts in.
+ *
+ * The plan comes out of planWagonsWithStock ordered by booking scheduling order
+ * (first slot opened = sequenceNo 1). When `reverse` is set, the physically-last
+ * wagon becomes wagon #1: the slot objects — and the bookings already allocated
+ * into each — travel WITH their slot, so only the position numbers flip. The
+ * physical composition, which booking is in which wagon, and every per-slot
+ * field are untouched; sequenceNo is renumbered 1..N over the reversed array.
+ *
+ * This single flip is the whole feature: persistTrainSetWagons writes these
+ * sequenceNos, the snapshot re-sorts by them, and the board/allocation views all
+ * read them — so the stored train order and the schedule order stay identical,
+ * just reversed. A false/absent flag returns the plan unchanged.
+ */
+export function applyWagonOrderReversal(
+  plan: WagonPlanSlot[],
+  reverse: boolean | null | undefined,
+): WagonPlanSlot[] {
+  if (!reverse) return plan;
+  return [...plan]
+    .reverse()
+    .map((slot, index) => ({ ...slot, sequenceNo: index + 1 }));
+}
+
 /** Unbounded stock — used to compute pure demand for availability reporting. */
 export function unboundedStock(allowed: AllowedWagonTypeMap): WagonStock {
   const remainingByTypeId = new Map<string, number>();