add contract management types and interfaces for freight contracts

apps/edr-freight-api/src/modules/bookings/road.util.ts

@@ -0,0 +1,35 @@
+import { ServiceType } from '../rule-engine/entities/service-type.entity';
+
+/**
+ * Road (truck) services are distinguished by their ServiceType.code. Rail
+ * services are seeded as RAIL_* and go through the train batch pool; a road
+ * service (code starting ROAD_ or TRUCK_, or exactly ROAD/TRUCK) instead bills
+ * by distance and dispatches a truck. Prefix-matching keeps this resilient to
+ * the exact seeded code (e.g. ROAD_CONTAINER, TRUCK_FORWARDING).
+ */
+export function isRoadService(
+  serviceType?: Pick<ServiceType, 'code'> | null,
+): boolean {
+  const code = serviceType?.code?.toUpperCase() ?? '';
+  return (
+    code === 'ROAD' ||
+    code === 'TRUCK' ||
+    code.startsWith('ROAD_') ||
+    code.startsWith('TRUCK_')
+  );
+}
+
+/**
+ * Road freight charge for an order: distance (km, from the route line) × the
+ * per-km rate. Returns 0 when either input is missing so callers can add it to
+ * a total without guarding.
+ */
+export function roadKmPrice(
+  km: number | null | undefined,
+  perKmRate: number | null | undefined,
+): number {
+  const distance = Number(km ?? 0);
+  const rate = Number(perKmRate ?? 0);
+  if (!(distance > 0) || !(rate > 0)) return 0;
+  return distance * rate;
+}