auto allocation and batch managemnt, tracking the train

apps/edr-freight-web/backoffice/src/components/trainScheduling/AllocateBookingWizard.tsx

@@ -136,9 +136,17 @@ export function AllocateBookingWizard({
   const eligibleQuery = useEligibleBookings(eligibleFilters, opened);
   const schedulesQuery = useScheduleList();
   const routesQuery = useRoutes();
-  const locomotivesQuery = useAvailableLocomotives();
+  const locomotivesQuery = useAvailableLocomotives(
+    scheduleMode === "new" && routeId ? routeId : undefined,
+  );
   const { create, preview, assign, finalize } = useScheduleMutations(selectedScheduleId ?? undefined);
 
+  useEffect(() => {
+    if (scheduleMode === "new") {
+      setLocomotiveId("");
+    }
+  }, [routeId, scheduleMode]);
+
   const matchingSchedules = useMemo(
     () =>
       (schedulesQuery.data ?? []).filter(
@@ -511,6 +519,7 @@ export function AllocateBookingWizard({
                   />
                   <Select
                     label="Locomotive"
+                    placeholder={routeId ? "Select locomotive" : "Select a route first"}
                     data={(locomotivesQuery.data ?? []).map((l) => ({
                       value: l.id,
                       label: `${l.code} · ${
@@ -520,6 +529,10 @@ export function AllocateBookingWizard({
                     value={locomotiveId || null}
                     onChange={(v) => setLocomotiveId(v ?? "")}
                     searchable
+                    disabled={!routeId}
+                    nothingFoundMessage={
+                      routeId ? "No available locomotives for this corridor" : "Select a route first"
+                    }
                   />
                 </SimpleGrid>
               )}