Show space hierarchies

Fixes #83

lib/controllers/client.dart

@@ -28,6 +28,7 @@ import "package:nexus/models/requests/get_event_context.dart";
 import "package:nexus/models/requests/get_mentions.dart";
 import "package:nexus/models/requests/get_related_events.dart";
 import "package:nexus/models/requests/get_room_state.dart";
+import "package:nexus/models/requests/get_space_hierarchy.dart";
 import "package:nexus/models/requests/join_room.dart";
 import "package:nexus/models/profile_response.dart";
 import "package:nexus/models/requests/oauth/exchange_token.dart";
@@ -47,6 +48,7 @@ import "package:nexus/models/requests/upload_media.dart";
 import "package:nexus/models/room.dart";
 import "package:nexus/models/room_metadata.dart";
 import "package:nexus/models/room_summary.dart";
+import "package:nexus/models/space_hierarchy.dart";
 import "package:nexus/models/spec_versions_response.dart";
 import "package:nexus/src/third_party/gomuks.g.dart";
 import "package:flutter_riverpod/flutter_riverpod.dart";
@@ -194,6 +196,11 @@ class ClientController extends AsyncNotifier<int> {
   Future<String> createRoom(CreateRoomRequest request) async =>
       (await _sendCommand("create_room", request.toJson()))["room_id"];
 
+  Future<SpaceHierarchy> getSpaceHierarchy(
+    GetSpaceHierarchyRequest request,
+  ) async =>
+      .fromJson(await _sendCommand("get_space_hierarchy", request.toJson()));
+
   Future<RoomSummary> getRoomSummary(JoinRoomRequest request) async =>
       .fromJson(await _sendCommand("get_room_summary", request.toJson()));
 

lib/controllers/space_hierarchy.dart

@@ -0,0 +1,34 @@
+import "package:hooks_riverpod/hooks_riverpod.dart";
+import "package:nexus/controllers/client.dart";
+import "package:nexus/models/space_hierarchy.dart";
+
+class SpaceHierarchyController(final String spaceId)
+    extends AsyncNotifier<SpaceHierarchy> {
+  @override
+  Future<SpaceHierarchy> build() => ref
+      .read(ClientController.provider.notifier)
+      .getSpaceHierarchy(.new(roomId: spaceId, maxDepth: 1));
+
+  Future<void> loadMore() async {
+    final current = await future;
+    if (current.nextBatch == null) return;
+
+    final next = await ref
+        .read(ClientController.provider.notifier)
+        .getSpaceHierarchy(
+          .new(roomId: spaceId, maxDepth: 1, from: current.nextBatch),
+        );
+
+    state = AsyncData(
+      current.copyWith(
+        rooms: current.rooms.addAll(next.rooms),
+        nextBatch: next.nextBatch,
+      ),
+    );
+  }
+
+  static final provider = AsyncNotifierProvider.family
+      .autoDispose<SpaceHierarchyController, SpaceHierarchy, String>(
+        SpaceHierarchyController.new,
+      );
+}

lib/helpers/extensions/show_leave_room_sheet.dart

@@ -0,0 +1,39 @@
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:material_ui/material_ui.dart";
+import "package:nexus/controllers/client.dart";
+import "package:nexus/helpers/extensions/show_adaptive_sheet.dart";
+import "package:nexus/helpers/extensions/with_progress_snackbar.dart";
+import "package:nexus/widgets/sheet_layout.dart";
+
+extension ShowLeaveRoomSheet on BuildContext {
+  /// Asks the user to confirm leaving the room, then leaves it.
+  Future<void> showLeaveRoomSheet(String roomId, {required String name}) =>
+      showAdaptiveSheet(
+        (context) => SheetLayout(
+          title: const Text("Leave Room"),
+          actions: [
+            TextButton(
+              onPressed: Navigator.of(context).pop,
+              child: const Text("Cancel"),
+            ),
+            TextButton(
+              onPressed: () {
+                final client = ProviderScope.containerOf(
+                  context,
+                ).read(ClientController.provider.notifier);
+                context.withProgressSnackbar(
+                  "Leaving $name...",
+                  () => client.leaveRoom(roomId),
+                );
+                Navigator.of(context).pop();
+              },
+              style: TextButton.styleFrom(
+                foregroundColor: Theme.of(context).colorScheme.error,
+              ),
+              child: const Text("Leave"),
+            ),
+          ],
+          children: [Text("Are you sure you want to leave \"$name\"?")],
+        ),
+      );
+}

lib/models/requests/get_space_hierarchy.dart

@@ -0,0 +1,19 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+
+part "get_space_hierarchy.freezed.dart";
+part "get_space_hierarchy.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable(includeIfNull: false)
+class const GetSpaceHierarchyRequest({
+  required final String roomId,
+  final String? from,
+  final int limit = 50,
+  final int? maxDepth,
+  final bool? suggestedOnly,
+}) with _$GetSpaceHierarchyRequest {
+  Map<String, Object?> toJson() => _$GetSpaceHierarchyRequestToJson(this);
+
+  factory GetSpaceHierarchyRequest.fromJson(Map<String, Object?> json) =>
+      _$GetSpaceHierarchyRequestFromJson(json);
+}

lib/models/space_hierarchy.dart

@@ -0,0 +1,45 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:freezed_annotation/freezed_annotation.dart";
+import "package:nexus/models/room_summary.dart";
+
+part "space_hierarchy.freezed.dart";
+part "space_hierarchy.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable(createToJson: false)
+class const SpaceHierarchy({
+  final IList<SpaceHierarchyRoom> rooms = const .empty(),
+  final String? nextBatch,
+}) with _$SpaceHierarchy {
+  factory SpaceHierarchy.fromJson(Map<String, Object?> json) =>
+      _$SpaceHierarchyFromJson(json);
+}
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable(createToJson: false)
+class const SpaceHierarchyRoom({
+  @JsonKey(readValue: SpaceHierarchyRoom.readEntry)
+  required final RoomSummary summary,
+  @JsonKey(name: "children_state")
+  final IList<SpaceHierarchyChild> children = const .empty(),
+}) with _$SpaceHierarchyRoom {
+  static Object? readEntry(Map json, String _) => json;
+
+  factory SpaceHierarchyRoom.fromJson(Map<String, Object?> json) =>
+      _$SpaceHierarchyRoomFromJson(json);
+}
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable(createToJson: false)
+class const SpaceHierarchyChild({
+  @JsonKey(name: "state_key") required final String roomId,
+  @JsonKey(readValue: SpaceHierarchyChild.readContent)
+  final IList<String> via = const .empty(),
+  @JsonKey(readValue: SpaceHierarchyChild.readContent)
+  final bool suggested = false,
+}) with _$SpaceHierarchyChild {
+  static Object? readContent(Map json, String key) => json["content"]?[key];
+
+  factory SpaceHierarchyChild.fromJson(Map<String, Object?> json) =>
+      _$SpaceHierarchyChildFromJson(json);
+}

lib/widgets/room_list.dart

@@ -2,6 +2,7 @@ import "dart:math";
 
 import "package:hooks_riverpod/hooks_riverpod.dart";
 import "package:material_ui/material_ui.dart";
+import "package:m3e_design/m3e_design.dart";
 import "package:navigation_rail_m3e/navigation_rail_m3e.dart";
 import "package:nexus/helpers/extensions/get_all_child_rooms.dart";
 import "package:nexus/helpers/extensions/room_destinations.dart";
@@ -16,6 +17,7 @@ import "package:nexus/widgets/error_dialog.dart";
 import "package:nexus/widgets/pages/settings.dart";
 import "package:nexus/widgets/join_sheet.dart";
 import "package:nexus/widgets/room_menu_button.dart";
+import "package:nexus/widgets/space_hierarchy_sheet.dart";
 import "package:nexus/controllers/key.dart";
 import "package:nexus/controllers/rooms.dart";
 import "package:nexus/controllers/spaces.dart";
@@ -252,74 +254,97 @@ class const RoomsPane({super.key}) extends ConsumerWidget {
       ),
       body: MaterialUiCompatibilityBridge(
         child: Builder(
-          builder: (context) => old_mat.Theme(
-            data: old_mat.Theme.of(context).copyWith(
-              extensions: [
-                NavigationRailM3ETheme(
-                  itemExpandedHeight: 48,
-                  iconLabelGap: 16,
-                ),
-              ],
-            ),
-            child: NavigationRailM3E(
-              expandedWidth: double.infinity,
-              scrollable: true,
-              background: Colors.transparent,
-              type: .alwaysExpand,
-              selectedIndex: max(
-                0,
-                selectedSpace.allChildRooms.indexWhere(
-                  (room) => room.metadata?.id == selectedRoomId,
-                ),
+          builder: (context) {
+            final theme = old_mat.Theme.of(context);
+            return old_mat.Theme(
+              data: theme.copyWith(
+                extensions: [
+                  NavigationRailM3ETheme(
+                    itemExpandedHeight: 48,
+                    iconLabelGap: 16,
+                    sectionHeaderSpacingTop: 0,
+                  ),
+                  // Otherwise the FAB label falls back to Roboto
+                  M3ETheme.defaults(theme.colorScheme).copyWith(
+                    typography: .defaultFor(
+                      theme.brightness,
+                      baseOverride: theme.textTheme,
+                    ),
+                  ),
+                ],
               ),
-              sections: [
-                .new(
-                  header: selectedSpace.room == null
-                      ? null
-                      : const DividerWidget(Text("Rooms")),
-                  destinations: selectedSpace.children.toDestinations(
-                    isDm: isDm,
+              child: NavigationRailM3E(
+                fab: selectedSpace.room == null
+                    ? null
+                    : .new(
+                        icon: const Icon(Icons.explore),
+                        label: "Browse space",
+                        tooltip: "Browse and join rooms in this space",
+                        onPressed: () => context.showAdaptiveSheet(
+                          (_) => SpaceHierarchySheet(selectedSpace.id),
+                        ),
+                      ),
+                expandedWidth: double.infinity,
+                scrollable: true,
+                background: Colors.transparent,
+                type: .alwaysExpand,
+                selectedIndex: max(
+                  0,
+                  selectedSpace.allChildRooms.indexWhere(
+                    (room) => room.metadata?.id == selectedRoomId,
                   ),
                 ),
-                ...selectedSpace.subSpaces.map(
-                  (subSpace) => NavigationRailM3ESection(
-                    header: DividerWidget(
-                      Row(
-                        mainAxisSize: .min,
-                        spacing: 8,
-                        children: [
-                          if (subSpace.room.metadata?.avatar != null)
-                            AvatarOrHash(
-                              subSpace.room.metadata?.avatar,
-                              subSpace.room.metadata?.name ?? "Unnamed Room",
-                              dimension: 16,
+                sections: [
+                  .new(
+                    header: selectedSpace.room == null
+                        ? null
+                        : const DividerWidget(Text("Rooms")),
+                    destinations: selectedSpace.children.toDestinations(
+                      isDm: isDm,
+                    ),
+                  ),
+                  ...selectedSpace.subSpaces.map(
+                    (subSpace) => NavigationRailM3ESection(
+                      header: DividerWidget(
+                        Row(
+                          mainAxisSize: .min,
+                          spacing: 8,
+                          children: [
+                            if (subSpace.room.metadata?.avatar != null)
+                              AvatarOrHash(
+                                subSpace.room.metadata?.avatar,
+                                subSpace.room.metadata?.name ?? "Unnamed Room",
+                                dimension: 16,
+                              ),
+                            Flexible(
+                              child: Text(
+                                subSpace.room.metadata?.name ?? "Unnamed Space",
+                                maxLines: 1,
+                                overflow: .ellipsis,
+                              ),
                             ),
-                          Flexible(
-                            child: Text(
-                              subSpace.room.metadata?.name ?? "Unnamed Space",
-                              maxLines: 1,
-                              overflow: .ellipsis,
-                            ),
-                          ),
-                        ],
+                          ],
+                        ),
+                      ),
+                      destinations: subSpace.children.toDestinations(
+                        isDm: isDm,
                       ),
                     ),
-                    destinations: subSpace.children.toDestinations(isDm: isDm),
                   ),
-                ),
-              ],
-              onDestinationSelected: (value) {
-                ref
-                    .read(
-                      KeyController.provider(KeyController.roomKey).notifier,
-                    )
-                    .set(selectedSpace.allChildRooms[value].metadata?.id);
-                if (Navigator.of(context).canPop()) {
-                  Navigator.of(context).pop();
-                }
-              },
-            ),
-          ),
+                ],
+                onDestinationSelected: (value) {
+                  ref
+                      .read(
+                        KeyController.provider(KeyController.roomKey).notifier,
+                      )
+                      .set(selectedSpace.allChildRooms[value].metadata?.id);
+                  if (Navigator.of(context).canPop()) {
+                    Navigator.of(context).pop();
+                  }
+                },
+              ),
+            );
+          },
         ),
       ),
     );

lib/widgets/room_menu_button.dart

@@ -1,7 +1,7 @@
 import "package:fast_immutable_collections/fast_immutable_collections.dart";
 import "package:material_ui/material_ui.dart";
 import "package:nexus/helpers/extensions/get_localpart.dart";
-import "package:nexus/helpers/extensions/with_progress_snackbar.dart";
+import "package:nexus/helpers/extensions/show_leave_room_sheet.dart";
 import "package:nexus/helpers/extensions/show_adaptive_sheet.dart";
 import "package:nexus/widgets/sheet_layout.dart";
 import "package:flutter/services.dart";
@@ -123,31 +123,9 @@ final class const RoomMenuButton(
             ),
           ),
           PopupMenuItem(
-            onTap: () => context.showAdaptiveSheet(
-              (context) => SheetLayout(
-                title: Text("Leave Room"),
-                actions: [
-                  TextButton(
-                    onPressed: Navigator.of(context).pop,
-                    child: Text("Cancel"),
-                  ),
-                  TextButton(
-                    onPressed: () {
-                      context.withProgressSnackbar(
-                        "Leaving room...",
-                        () => client.leaveRoom(room!.metadata!.id),
-                      );
-                      Navigator.of(context).pop();
-                    },
-                    child: Text("Leave"),
-                  ),
-                ],
-                children: [
-                  Text(
-                    "Are you sure you want to leave \"${room!.metadata?.name ?? "Unnamed Room"}\"?",
-                  ),
-                ],
-              ),
+            onTap: () => context.showLeaveRoomSheet(
+              room!.metadata!.id,
+              name: room!.metadata?.name ?? "Unnamed Room",
             ),
             child: ListTile(
               leading: Icon(Icons.logout, color: danger),

lib/widgets/space_hierarchy_sheet.dart

@@ -0,0 +1,263 @@
+import "package:collection/collection.dart";
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:flutter_hooks/flutter_hooks.dart";
+import "package:hooks_riverpod/hooks_riverpod.dart";
+import "package:material_ui/material_ui.dart";
+import "package:nexus/controllers/rooms.dart";
+import "package:nexus/controllers/space_hierarchy.dart";
+import "package:nexus/helpers/extensions/better_when.dart";
+import "package:nexus/helpers/extensions/join_room.dart";
+import "package:nexus/helpers/extensions/show_adaptive_sheet.dart";
+import "package:nexus/helpers/extensions/show_leave_room_sheet.dart";
+import "package:nexus/main.dart";
+import "package:nexus/models/content/create.dart";
+import "package:nexus/models/space_hierarchy.dart";
+import "package:nexus/widgets/avatar_or_hash.dart";
+import "package:nexus/widgets/expandable_image.dart";
+import "package:nexus/widgets/loading.dart";
+import "package:nexus/widgets/room_summary_sheet.dart";
+import "package:nexus/widgets/sheet_layout.dart";
+
+class const SpaceHierarchySheet(final String spaceId, {super.key})
+    extends ConsumerWidget {
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final joinedIds = ref.watch(
+      RoomsController.provider.select((rooms) => rooms.keys.toISet()),
+    );
+
+    void showSummary(SpaceHierarchyRoom room, SpaceHierarchyChild child) =>
+        context.showAdaptiveSheet(
+          (_) => RoomSummarySheet(
+            room.summary,
+            via: joinedIds.contains(room.summary.roomId) ? null : child.via,
+          ),
+        );
+
+    Widget membershipButton(
+      SpaceHierarchyRoom room,
+      SpaceHierarchyChild child, {
+      required String name,
+    }) => joinedIds.contains(room.summary.roomId)
+        ? TextButton(
+            onPressed: () =>
+                context.showLeaveRoomSheet(room.summary.roomId, name: name),
+            style: TextButton.styleFrom(
+              foregroundColor: Theme.of(context).colorScheme.error,
+            ),
+            child: const Text("Leave"),
+          )
+        : TextButton(
+            onPressed: () => context.joinRoom(
+              .new(roomIdOrAlias: room.summary.roomId, via: child.via),
+              name: name,
+            ),
+            child: const Text("Join"),
+          );
+
+    Widget level(
+      String spaceId,
+      SpaceHierarchy hierarchy,
+      ISet<String> ancestors,
+    ) => HookConsumer(
+      builder: (context, ref, _) {
+        final loadingMore = useState(false);
+
+        final byId = IMap.fromValues(
+          keyMapper: (room) => room.summary.roomId,
+          values: hierarchy.rooms,
+        );
+        final children = (byId[spaceId]?.children ?? const .empty())
+            .map(
+              (child) => switch (byId[child.roomId]) {
+                // Skip spaces that contain themselves somewhere up the tree.
+                final room? when !ancestors.contains(child.roomId) => (
+                  child,
+                  room,
+                ),
+                _ => null,
+              },
+            )
+            .nonNulls
+            // Suggested rooms first, then sorted by member count
+            .sorted((a, b) {
+              if (a.$1.suggested != b.$1.suggested) {
+                return a.$1.suggested ? -1 : 1;
+              }
+              return (b.$2.summary.joinedMembers ?? 0).compareTo(
+                a.$2.summary.joinedMembers ?? 0,
+              );
+            });
+
+        return Column(
+          crossAxisAlignment: .stretch,
+          children: [
+            for (final (child, room) in children)
+              if (room.summary.roomType != RoomType.space)
+                Builder(
+                  builder: (context) {
+                    final summary = room.summary;
+                    final name =
+                        summary.name ??
+                        summary.canonicalAlias ??
+                        "Unnamed Room";
+
+                    return ListTile(
+                      leading: AvatarOrHash(
+                        summary.avatarUrl,
+                        name,
+                        fallback: const Icon(Icons.numbers),
+                      ),
+                      title: Text(name, maxLines: 1, overflow: .ellipsis),
+                      subtitle: summary.topic == null
+                          ? null
+                          : Text(
+                              summary.topic!,
+                              maxLines: 2,
+                              overflow: .ellipsis,
+                            ),
+                      onTap: () => showSummary(room, child),
+                      trailing: membershipButton(room, child, name: name),
+                    );
+                  },
+                ),
+            for (final (child, room) in children)
+              if (room.summary.roomType == RoomType.space)
+                HookConsumer(
+                  builder: (context, ref, _) {
+                    final expanded = useState(false);
+                    final summary = room.summary;
+                    final name =
+                        summary.name ??
+                        summary.canonicalAlias ??
+                        "Unnamed Space";
+                    final joined = joinedIds.contains(summary.roomId);
+
+                    return Column(
+                      crossAxisAlignment: .stretch,
+                      children: [
+                        ListTile(
+                          onTap: joined
+                              ? () => expanded.value = !expanded.value
+                              : () => showSummary(room, child),
+                          leading: AvatarOrHash(
+                            summary.avatarUrl,
+                            name,
+                            fallback: const Icon(Icons.workspaces),
+                          ),
+                          title: Text(name, maxLines: 1, overflow: .ellipsis),
+                          subtitle: summary.topic == null
+                              ? null
+                              : Text(
+                                  summary.topic!,
+                                  maxLines: 2,
+                                  overflow: .ellipsis,
+                                ),
+                          trailing: Row(
+                            mainAxisSize: .min,
+                            children: [
+                              if (joined)
+                                AnimatedRotation(
+                                  turns: expanded.value ? 0.5 : 0,
+                                  duration: Durations.medium2,
+                                  child: const Icon(Icons.expand_more),
+                                ),
+                              membershipButton(room, child, name: name),
+                            ],
+                          ),
+                        ),
+                        AnimatedSize(
+                          duration: Durations.medium2,
+                          curve: Curves.easeInOut,
+                          alignment: .topCenter,
+                          child: joined && expanded.value
+                              ? Padding(
+                                  // Indented so it's clear which rooms are in which space
+                                  padding: const .only(left: 16),
+                                  child: ref
+                                      .watch(
+                                        SpaceHierarchyController.provider(
+                                          summary.roomId,
+                                        ),
+                                      )
+                                      .betterWhen(
+                                        loading: () =>
+                                            const Loading(dimension: 24),
+                                        data: (hierarchy) => level(
+                                          summary.roomId,
+                                          hierarchy,
+                                          ancestors.add(child.roomId),
+                                        ),
+                                      ),
+                                )
+                              : const SizedBox(width: .infinity),
+                        ),
+                      ],
+                    );
+                  },
+                ),
+            if (hierarchy.nextBatch != null)
+              Center(
+                child: TextButton(
+                  onPressed: loadingMore.value
+                      ? null
+                      : () async {
+                          loadingMore.value = true;
+                          await ref
+                              .read(
+                                SpaceHierarchyController.provider(spaceId)
+                                    .notifier,
+                              )
+                              .loadMore()
+                              .onError(showError);
+                          if (context.mounted) loadingMore.value = false;
+                        },
+                  child: const Text("Load more"),
+                ),
+              ),
+          ],
+        );
+      },
+    );
+
+    return ref
+        .watch(SpaceHierarchyController.provider(spaceId))
+        .betterWhen(
+          data: (hierarchy) {
+            final space = hierarchy.rooms
+                .where((room) => room.summary.roomId == spaceId)
+                .firstOrNull
+                ?.summary;
+
+            return SheetLayout(
+              title: Row(
+                spacing: 12,
+                children: [
+                  if (space?.avatarUrl case final avatarUrl?)
+                    ExpandableImage(
+                      .new(mxc: avatarUrl),
+                      child: AvatarOrHash(avatarUrl, "", dimension: 32),
+                    ),
+                  Expanded(
+                    child: Text(
+                      space?.name ?? space?.canonicalAlias ?? "Unnamed Space",
+                      overflow: .ellipsis,
+                      maxLines: 3,
+                    ),
+                  ),
+                ],
+              ),
+              actions: [
+                TextButton(
+                  onPressed: Navigator.of(context).pop,
+                  child: const Text("Close"),
+                ),
+              ],
+              children: [
+                level(spaceId, hierarchy, .new([spaceId])),
+              ],
+            );
+          },
+        );
+  }
+}