Update room suggestions and search when space membership changes (#6316)

* Avoid repeated space membership scans in room search

Signed-off-by: Ivan Magda <imagda15@gmail.com>

* Refresh room candidates when space membership changes

Keep known space room IDs in a set updated by the room publisher and by
successful additions. Filter both suggestions and search results through
that set, retaining exclusions while the space list resets and reloads.

Preserve the initial recent-room eligibility filter so existing children
do not consume the five suggestion slots. Cover live membership updates
and partial-save filtering in both candidate lists.

---------

Signed-off-by: Ivan Magda <imagda15@gmail.com>

UnitTests/Sources/SpaceAddRoomsScreenViewModelTests.swift

@@ -25,7 +25,7 @@ struct SpaceAddRoomsScreenViewModelTests {
         spaceRoomListProxy = SpaceRoomListProxyMock(.init(spaceServiceRoom: SpaceServiceRoom.mock(isSpace: true)))
         
         let clientProxy = ClientProxyMock(.init())
-        clientProxy.recentlyVisitedRoomsFilterReturnValue = .init(repeating: JoinedRoomProxyMock(.init()), count: 5)
+        clientProxy.recentlyVisitedRoomsFilterReturnValue = (0..<5).map { JoinedRoomProxyMock(.init(id: "suggestion-\($0)")) }
         spaceServiceProxy = clientProxy.spaceService as? SpaceServiceProxyMock ?? SpaceServiceProxyMock(.init())
         
         viewModel = SpaceAddRoomsScreenViewModel(spaceRoomListProxy: spaceRoomListProxy,
@@ -63,21 +63,23 @@ struct SpaceAddRoomsScreenViewModelTests {
         #expect(spaceRoomListProxy.resetCalled, "The room list should be reset to pick up the changes.")
     }
     
-    @Test
-    func failureWithMultipleRoomsSelected() async throws {
-        // Given a view model with 4 selected rooms.
+    @Test(arguments: [true, false])
+    func failureWithMultipleRoomsSelected(search: Bool) async throws {
+        let initialCount = search ? 4 : 5
+        let sectionType: SpaceAddRoomsScreenViewState.Section.SectionType = search ? .searchResults : .suggestions
+        // Given a view model with several selected rooms.
         var deferred = deferFulfillment(context.observe(\.viewState.roomsSection),
-                                        message: "There should be 4 search results.") { section in
-            section.type == .searchResults && section.rooms.count == 4
+                                        message: "The candidate rooms should be shown.") { section in
+            section.type == sectionType && section.rooms.count == initialCount
         }
-        context.searchQuery = "f"
+        context.searchQuery = search ? "f" : ""
         context.send(viewAction: .searchQueryChanged)
         try await deferred.fulfill()
         
         for room in context.viewState.roomsSection.rooms {
             context.send(viewAction: .toggleRoom(room))
         }
-        #expect(context.viewState.selectedRooms.count == 4, "All of the rooms should be selected.")
+        #expect(context.viewState.selectedRooms.count == initialCount, "All of the rooms should be selected.")
         
         // When there's a failure half way through saving.
         let successfulIDs = context.viewState.roomsSection.rooms.map(\.id).prefix(2)
@@ -90,8 +92,8 @@ struct SpaceAddRoomsScreenViewModelTests {
         }
         
         deferred = deferFulfillment(context.observe(\.viewState.roomsSection),
-                                    message: "The search results should update.") { section in
-            section.type == .searchResults && section.rooms.count == 2
+                                    message: "The candidates should update after a partial save.") { section in
+            section.type == sectionType && section.rooms.count == initialCount - 2
         }
         context.send(viewAction: .save)
         try await deferred.fulfill()
@@ -103,4 +105,50 @@ struct SpaceAddRoomsScreenViewModelTests {
         #expect(!context.viewState.roomsSection.rooms.contains { successfulIDs.contains($0.id) },
                 "The added rooms should no longer be listed for selection.")
     }
+    
+    @Test(arguments: [true, false])
+    func spaceMembershipUpdatesCandidates(search: Bool) async throws {
+        let summaries = [RoomSummary.mock(id: "first", name: "First room"),
+                         .mock(id: "existing", name: "Existing room"),
+                         .mock(id: "second", name: "Second room")]
+        let summariesSubject = CurrentValueSubject<[RoomSummary], Never>(summaries)
+        let summaryProvider = RoomSummaryProviderMock(.init(state: .loaded([])))
+        summaryProvider.roomListPublisher = summariesSubject.asCurrentValuePublisher()
+        let spaceRoomsSubject = CurrentValueSubject<[SpaceServiceRoom], Never>([.mock(id: "existing", isSpace: false)])
+        spaceRoomListProxy.spaceRoomsPublisher = spaceRoomsSubject.asCurrentValuePublisher()
+        let clientProxy = ClientProxyMock(.init())
+        let recentRooms = summaries.map { JoinedRoomProxyMock(.init(id: $0.id)) }
+        clientProxy.recentlyVisitedRoomsFilterClosure = { filter in
+            var rooms: [JoinedRoomProxyProtocol] = []
+            for room in recentRooms where await filter(room) {
+                rooms.append(room)
+            }
+            return rooms
+        }
+        let viewModel = SpaceAddRoomsScreenViewModel(spaceRoomListProxy: spaceRoomListProxy,
+                                                     userSession: UserSessionMock(.init(clientProxy: clientProxy)),
+                                                     roomSummaryProvider: summaryProvider,
+                                                     userIndicatorController: UserIndicatorControllerMock())
+        let context = viewModel.context
+        context.searchQuery = search ? "room" : ""
+        var deferred = deferFulfillment(context.observe(\.viewState.roomsSection)) {
+            $0.rooms.map(\.id) == ["first", "second"]
+        }
+        try await deferred.fulfill()
+        
+        deferred = deferFulfillment(context.observe(\.viewState.roomsSection)) {
+            $0.rooms.map(\.id) == ["second"]
+        }
+        spaceRoomsSubject.send([.mock(id: "existing", isSpace: false), .mock(id: "first", isSpace: false)])
+        try await deferred.fulfill()
+        
+        // An empty snapshot during reload must not make known children selectable again.
+        deferred = deferFulfillment(context.observe(\.viewState.roomsSection)) {
+            $0.type == .searchResults && $0.rooms.map(\.id) == ["second", "third"]
+        }
+        spaceRoomsSubject.send([])
+        context.searchQuery = "room"
+        summariesSubject.send(summaries + [.mock(id: "third", name: "Third room")])
+        try await deferred.fulfill()
+    }
 }