Room List Filters implementation (#2423)

ElementX/Sources/Screens/HomeScreen/View/Filters/RoomListFilterModels.swift

@@ -0,0 +1,119 @@
+//
+// Copyright 2024 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Combine
+import Foundation
+
+import MatrixRustSDK
+
+enum RoomListFilter: Int, CaseIterable, Identifiable {
+    var id: Int {
+        rawValue
+    }
+    
+    case people
+    case rooms
+    case unreads
+    case favourites
+    
+    var localizedName: String {
+        switch self {
+        case .people:
+            return L10n.screenRoomlistFilterPeople
+        case .rooms:
+            return L10n.screenRoomlistFilterRooms
+        case .unreads:
+            return L10n.screenRoomlistFilterUnreads
+        case .favourites:
+            return L10n.screenRoomlistFilterFavourites
+        }
+    }
+    
+    var incompatibleFilter: RoomListFilter? {
+        switch self {
+        case .people:
+            return .rooms
+        case .rooms:
+            return .people
+        case .unreads:
+            return nil
+        case .favourites:
+            // When we will have Low Priority we may need to return it here
+            return nil
+        }
+    }
+    
+    var rustFilter: RoomListEntriesDynamicFilterKind? {
+        switch self {
+        case .people:
+            return .category(expect: .people)
+        case .rooms:
+            return .category(expect: .group)
+        case .unreads:
+            return .unread
+        case .favourites:
+            // Not implemented yet
+            return nil
+        }
+    }
+}
+
+final class RoomListFiltersState: ObservableObject {
+    @Published private(set) var activeFilters: Set<RoomListFilter>
+    
+    init(activeFilters: Set<RoomListFilter> = []) {
+        self.activeFilters = activeFilters
+    }
+    
+    var sortedActiveFilters: [RoomListFilter] {
+        activeFilters.sorted(by: { $0.rawValue < $1.rawValue })
+    }
+    
+    var availableFilters: [RoomListFilter] {
+        var availableFilters = Set(RoomListFilter.allCases)
+        for filter in activeFilters {
+            availableFilters.remove(filter)
+            if let complementaryFilter = filter.incompatibleFilter {
+                availableFilters.remove(complementaryFilter)
+            }
+        }
+        return availableFilters.sorted(by: { $0.rawValue < $1.rawValue })
+    }
+    
+    var isFiltering: Bool {
+        !activeFilters.isEmpty
+    }
+    
+    func activateFilter(_ filter: RoomListFilter) {
+        if let incompatibleFilter = filter.incompatibleFilter,
+           activeFilters.contains(incompatibleFilter) {
+            fatalError("[RoomListFiltersState] adding mutually exclusive filters is not allowed")
+        }
+        activeFilters.insert(filter)
+    }
+    
+    func deactivateFilter(_ filter: RoomListFilter) {
+        activeFilters.remove(filter)
+    }
+    
+    func clearFilters() {
+        activeFilters.removeAll()
+    }
+    
+    func isFilterActive(_ filter: RoomListFilter) -> Bool {
+        activeFilters.contains(filter)
+    }
+}

ElementX/Sources/Screens/HomeScreen/View/Filters/RoomListFilterView.swift

@@ -22,9 +22,9 @@ struct RoomListFilterView: View {
 
     var body: some View {
         let binding = Binding<Bool>(get: {
-            state.isEnabled(filter)
+            state.isFilterActive(filter)
         }, set: { isEnabled, _ in
-            state.set(filter, isEnabled: isEnabled)
+            isEnabled ? state.activateFilter(filter) : state.deactivateFilter(filter)
         })
         Toggle(isOn: binding) {
             Text(filter.localizedName)
@@ -36,7 +36,7 @@ struct RoomListFilterView: View {
 struct RoomListFilterView_Previews: PreviewProvider, TestablePreview {
     static var previews: some View {
         RoomListFilterView(filter: .people, state: .init())
-        RoomListFilterView(filter: .people, state: .init(enabledFilters: [.people]))
+        RoomListFilterView(filter: .people, state: .init(activeFilters: [.people]))
     }
 }
 

ElementX/Sources/Screens/HomeScreen/View/Filters/RoomListFiltersView.swift

@@ -31,10 +31,10 @@ struct RoomListFiltersView: View {
                         .hidden()
                         .frame(width: 0)
                 }
-                ForEach(state.sortedEnabledFilters) { filter in
+                ForEach(state.sortedActiveFilters) { filter in
                     RoomListFilterView(filter: filter, state: state)
                 }
-                ForEach(state.sortedAvailableFilters) { filter in
+                ForEach(state.availableFilters) { filter in
                     RoomListFilterView(filter: filter, state: state)
                 }
             }
@@ -62,6 +62,6 @@ struct RoomListFiltersView: View {
 struct RoomListFiltersView_Previews: PreviewProvider, TestablePreview {
     static var previews: some View {
         RoomListFiltersView(state: .init())
-        RoomListFiltersView(state: .init(enabledFilters: [.rooms, .favourites]))
+        RoomListFiltersView(state: .init(activeFilters: [.rooms, .favourites]))
     }
 }