Fix flights map transfer toggle fallback

src/features/flights-map/components/FlightsMapStartPage.test.tsx

@@ -10,6 +10,7 @@ import { transformDictionaries } from "@/shared/dictionaries/index.js";
 import type { IDictionaries, IRawDictionaries } from "@/shared/dictionaries/index.js";
 import type {
   FlightsMapCalendarParams,
+  IFlightsMapFilterState,
   FlightsMapSearchParams,
 } from "../types.js";
 import {
@@ -383,6 +384,7 @@ describe("TZ §4.1.4 Table 7 breadcrumbs — Flight-Map pages (rows 1-3)", () =>
 describe("FlightsMapStartPage — C.4 integration", () => {
   beforeEach(() => {
     lastMapCanvasProps = null;
+    lastMapFilterProps = null;
     searchCalls.length = 0;
     dictState.dictionaries = buildDictionaries({
       regions: [],
@@ -513,6 +515,33 @@ describe("FlightsMapStartPage — C.4 integration", () => {
     const last = [...searchCalls].reverse().find((p) => p?.departure && p?.arrival);
     expect(last?.connections).toBe(1);
   });
+
+  it("keeps transfer-only toggle off after the user disables auto-fallback", () => {
+    searchState.routes = [];
+    render(<FlightsMapStartPage />);
+    act(() => {
+      (lastMapCanvasProps!["onMarkerClick"] as (id: string) => void)("MOW");
+    });
+    act(() => {
+      (lastMapCanvasProps!["onMarkerClick"] as (id: string) => void)("LED");
+    });
+
+    const autoFallbackValue = lastMapFilterProps!["value"] as IFlightsMapFilterState;
+    expect(autoFallbackValue.connections).toBe(true);
+
+    act(() => {
+      (lastMapFilterProps!["onChange"] as (state: IFlightsMapFilterState) => void)({
+        ...autoFallbackValue,
+        connections: false,
+      });
+    });
+
+    const userValue = lastMapFilterProps!["value"] as IFlightsMapFilterState;
+    expect(userValue.connections).toBe(false);
+
+    const last = [...searchCalls].reverse().find((p) => p?.departure && p?.arrival);
+    expect(last?.connections).toBe(0);
+  });
 });
 
 // ---------------------------------------------------------------------------

src/features/flights-map/components/FlightsMapStartPage.tsx

@@ -161,6 +161,8 @@ export const FlightsMapStartPage: FC<FlightsMapStartPageProps> = ({
   const [effectiveConnections, setEffectiveConnections] = useState<0 | 1>(
     filterState.connections ? 1 : 0,
   );
+  const [connectionsFallbackSuppressed, setConnectionsFallbackSuppressed] =
+    useState(false);
 
   const persistFilterState = useCallback((newState: IFlightsMapFilterState) => {
     setFilterState(newState);
@@ -225,6 +227,7 @@ export const FlightsMapStartPage: FC<FlightsMapStartPageProps> = ({
   useEffect(() => {
     if (loading || error) return;
     if (effectiveConnections !== 0) return;
+    if (connectionsFallbackSuppressed) return;
     if (!filterState.departure || !filterState.arrival) return;
     if (routes.length > 0) return;
     setEffectiveConnections(1);
@@ -232,6 +235,7 @@ export const FlightsMapStartPage: FC<FlightsMapStartPageProps> = ({
     loading,
     error,
     effectiveConnections,
+    connectionsFallbackSuppressed,
     filterState.departure,
     filterState.arrival,
     routes,
@@ -239,14 +243,43 @@ export const FlightsMapStartPage: FC<FlightsMapStartPageProps> = ({
 
   // Reflect fallback in the UI toggle once.
   useEffect(() => {
-    if (filterState.arrival && effectiveConnections === 1 && !filterState.connections) {
+    if (
+      filterState.arrival &&
+      effectiveConnections === 1 &&
+      !filterState.connections &&
+      !connectionsFallbackSuppressed
+    ) {
       setFilterState((prev) => ({ ...prev, connections: true }));
     }
-  }, [effectiveConnections, filterState.arrival, filterState.connections]);
+  }, [
+    effectiveConnections,
+    filterState.arrival,
+    filterState.connections,
+    connectionsFallbackSuppressed,
+  ]);
 
   const handleFilterChange = useCallback((newState: IFlightsMapFilterState) => {
+    const sameRoute =
+      newState.departure === filterState.departure &&
+      newState.arrival === filterState.arrival;
+    const turnedConnectionsOff =
+      sameRoute && filterState.connections && !newState.connections;
+
+    setConnectionsFallbackSuppressed(
+      turnedConnectionsOff
+        ? true
+        : sameRoute && !newState.connections
+          ? connectionsFallbackSuppressed
+          : false,
+    );
     persistFilterState(newState);
-  }, [persistFilterState]);
+  }, [
+    connectionsFallbackSuppressed,
+    filterState.arrival,
+    filterState.connections,
+    filterState.departure,
+    persistFilterState,
+  ]);
 
   const handleMarkerClick = useCallback(
     (markerId: string) => {