add room directory support

lib/controllers/client.dart

@@ -36,6 +36,7 @@ import "package:nexus/models/requests/get_related_events.dart";
 import "package:nexus/models/requests/get_room_state.dart";
 import "package:nexus/models/requests/get_specific_room_state.dart";
 import "package:nexus/models/requests/get_space_hierarchy.dart";
+import "package:nexus/models/requests/get_room_directory.dart";
 import "package:nexus/models/requests/join_room.dart";
 import "package:nexus/models/profile_response.dart";
 import "package:nexus/models/push_notification.dart";
@@ -57,6 +58,7 @@ import "package:nexus/models/requests/set_state.dart";
 import "package:nexus/models/requests/update_push_rule.dart";
 import "package:nexus/models/requests/upload_media.dart";
 import "package:nexus/models/room.dart";
+import "package:nexus/models/room_directory.dart";
 import "package:nexus/models/room_summary.dart";
 import "package:nexus/models/space_hierarchy.dart";
 import "package:nexus/models/spec_versions_response.dart";
@@ -311,6 +313,11 @@ class ClientController(final String? accountId) extends AsyncNotifier<int> {
   ) async =>
       .fromJson(await _sendCommand("get_space_hierarchy", request.toJson()));
 
+  Future<RoomDirectory> getRoomDirectory(
+    GetRoomDirectoryRequest request,
+  ) async =>
+      .fromJson(await _sendCommand("get_room_directory", request.toJson()));
+
   Future<RoomSummary> getRoomSummary(JoinRoomRequest request) async =>
       .fromJson(await _sendCommand("get_room_summary", request.toJson()));
 

lib/controllers/room_directory.dart

@@ -0,0 +1,39 @@
+import "package:flutter_riverpod/experimental/mutation.dart";
+import "package:hooks_riverpod/hooks_riverpod.dart";
+import "package:nexus/controllers/client.dart";
+import "package:nexus/models/room_directory.dart";
+
+/// The public room directory of a server, or of the user's own if null.
+class RoomDirectoryController(final String? server)
+    extends AsyncNotifier<RoomDirectory> {
+  @override
+  Future<RoomDirectory> build() => ref
+      .read(ClientController.provider.notifier)
+      .getRoomDirectory(.new(server: server));
+
+  Future<void> loadMore() async {
+    final current = await future;
+    if (current.nextBatch == null) return;
+
+    final next = await ref
+        .read(ClientController.provider.notifier)
+        .getRoomDirectory(.new(server: server, since: current.nextBatch));
+
+    if (!ref.mounted) return;
+
+    state = AsyncData(
+      current.copyWith(
+        rooms: current.rooms.addAll(next.rooms),
+        nextBatch: next.nextBatch,
+      ),
+    );
+  }
+
+  /// Loading the next page of a directory, keyed by its server
+  static final loadMoreMutation = Mutation<void>();
+
+  static final provider = AsyncNotifierProvider.family
+      .autoDispose<RoomDirectoryController, RoomDirectory, String?>(
+        RoomDirectoryController.new,
+      );
+}

lib/helpers/extensions/get_localpart.dart

@@ -4,6 +4,12 @@ extension GetLocalpart on String {
   /// Whether this looks like a valid Matrix user ID, e.g. `@user:example.com`.
   bool get isValidUserId => RegExp(r"^@[^:\s]+:[^\s]+$").hasMatch(this);
 
+  /// Whether this is a valid Matrix server name, e.g. `example.com:8448`.
+  bool get isValidServerName => RegExp(
+    r"^(\[[0-9a-f:.]+\]|[a-z0-9.-]{1,255})(:\d{1,5})?$",
+    caseSensitive: false,
+  ).hasMatch(this);
+
   String? get serverName {
     final index = indexOf(":");
     return index == -1 ? null : substring(index + 1);

lib/helpers/extensions/join_room.dart

@@ -17,6 +17,7 @@ extension JoinRoom on BuildContext {
   }) async {
     final container = ProviderScope.containerOf(this);
     final messenger = ScaffoldMessenger.of(this);
+    final navigator = Navigator.of(this);
 
     final roomId = await withProgressSnackbar(
       "Joining $name...",
@@ -31,6 +32,7 @@ extension JoinRoom on BuildContext {
         action: .new(
           label: "Open",
           onPressed: () async {
+            navigator.popUntil((route) => route.isFirst);
             await container.focusRoom(roomId);
             container.read(SidebarPageController.provider.notifier).set(.rooms);
           },

lib/helpers/extensions/room_summary_display.dart

@@ -0,0 +1,18 @@
+import "package:material_ui/material_ui.dart";
+import "package:nexus/models/content/create.dart";
+import "package:nexus/models/room_summary.dart";
+
+extension RoomSummaryDisplay on RoomSummary {
+  bool get isSpace => roomType == RoomType.space;
+
+  IconData get icon => isSpace ? Icons.workspaces : Icons.numbers;
+
+  String get displayName =>
+      name ?? canonicalAlias ?? (isSpace ? "Unnamed Space" : "Unnamed Room");
+
+  /// E.g. "Space · 12 members"
+  String get details => [
+    if (isSpace) "Space",
+    if (joinedMembers case final members?) "$members members",
+  ].join(" · ");
+}

lib/models/content/bot_command_description.dart

@@ -2,6 +2,7 @@ import "package:collection/collection.dart";
 import "package:fast_immutable_collections/fast_immutable_collections.dart";
 import "package:freezed_annotation/freezed_annotation.dart";
 import "package:nexus/helpers/extensions/get_link_info.dart";
+import "package:nexus/helpers/extensions/get_localpart.dart";
 import "package:nexus/models/content/content.dart";
 
 part "bot_command_description.freezed.dart";
@@ -181,10 +182,6 @@ enum BotPrimitiveType(final String label, final String expected) {
   @JsonValue("event_id")
   eventId("event", r"a message link or event ID like $abc");
 
-  static final serverNamePattern = RegExp(
-    r"^(\[[0-9A-Fa-f:.]+\]|[A-Za-z0-9.-]+)(:\d{1,5})?$",
-  );
-
   Object? parse(String text, {required String roomId}) {
     final (:identifier, :eventId, :via) =
         text.linkInfo ??
@@ -206,7 +203,7 @@ enum BotPrimitiveType(final String label, final String expected) {
         identifier,
       .roomAlias when identifier.startsWith("#") && identifier.contains(":") =>
         identifier,
-      .serverName when serverNamePattern.hasMatch(text) => text,
+      .serverName when text.isValidServerName => text,
       .roomId when identifier.startsWith("!") && eventId == null => {
         "type": "room_id",
         "id": identifier,

lib/models/requests/get_room_directory.dart

@@ -0,0 +1,28 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+
+part "get_room_directory.freezed.dart";
+part "get_room_directory.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable(includeIfNull: false, explicitToJson: true)
+class const GetRoomDirectoryRequest({
+  final String? server,
+  final int limit = 48,
+  final String? since,
+  final PublicRoomsFilter? filter,
+}) with _$GetRoomDirectoryRequest {
+  Map<String, Object?> toJson() => _$GetRoomDirectoryRequestToJson(this);
+
+  factory GetRoomDirectoryRequest.fromJson(Map<String, Object?> json) =>
+      _$GetRoomDirectoryRequestFromJson(json);
+}
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable(includeIfNull: false)
+class const PublicRoomsFilter({final String? genericSearchTerm})
+    with _$PublicRoomsFilter {
+  Map<String, Object?> toJson() => _$PublicRoomsFilterToJson(this);
+
+  factory PublicRoomsFilter.fromJson(Map<String, Object?> json) =>
+      _$PublicRoomsFilterFromJson(json);
+}

lib/models/room_directory.dart

@@ -0,0 +1,17 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:freezed_annotation/freezed_annotation.dart";
+import "package:nexus/models/room_summary.dart";
+
+part "room_directory.freezed.dart";
+part "room_directory.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable(createToJson: false)
+class const RoomDirectory({
+  @JsonKey(name: "chunk") final IList<RoomSummary> rooms = const .empty(),
+  final String? nextBatch,
+  final int? totalRoomCountEstimate,
+}) with _$RoomDirectory {
+  factory RoomDirectory.fromJson(Map<String, Object?> json) =>
+      _$RoomDirectoryFromJson(json);
+}

lib/models/settings.dart

@@ -1,3 +1,4 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
 import "package:material_ui/material_ui.dart";
 import "package:freezed_annotation/freezed_annotation.dart";
 import "package:nexus/models/name_color.dart";
@@ -25,6 +26,10 @@ class const Settings({
   /// When not sending, read receipts are still sent privately, so that the
   /// user's other devices know what has been read.
   final ShowAndSend readReceipts = .showAndSend,
+  final IList<String> directoryServers = const IListConst([
+    "matrix.org",
+    "matrixrooms.info",
+  ]),
 }) with _$Settings {
   Map<String, Object?> toJson() => _$SettingsToJson(this);
 

lib/widgets/add_directory_server_sheet.dart

@@ -0,0 +1,54 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:flutter_hooks/flutter_hooks.dart";
+import "package:material_ui/material_ui.dart";
+import "package:material_adaptive_sheets/material_adaptive_sheets.dart";
+import "package:nexus/helpers/extensions/get_localpart.dart";
+
+class const AddDirectoryServerSheet({
+  required final ISet<String> existing,
+  super.key,
+}) extends HookWidget {
+  @override
+  Widget build(BuildContext context) {
+    final controller = useTextEditingController();
+    final text = useValueListenable(controller).text;
+    final server = text.trim().toLowerCase();
+    final error = server.isEmpty
+        ? null
+        : !server.isValidServerName
+        ? "Enter a server name, without https:// or a path"
+        : existing.contains(server)
+        ? "This server has already been added"
+        : null;
+    final valid = server.isNotEmpty && error == null;
+
+    void submit() {
+      if (valid) Navigator.of(context).pop(server);
+    }
+
+    return SheetLayout(
+      title: const Text("Add Server"),
+      actions: [
+        TextButton(
+          onPressed: Navigator.of(context).pop,
+          child: const Text("Cancel"),
+        ),
+        TextButton(onPressed: valid ? submit : null, child: const Text("Add")),
+      ],
+      children: [
+        const Text("Enter a server to browse the public rooms of."),
+        TextField(
+          controller: controller,
+          autofocus: true,
+          keyboardType: .url,
+          onSubmitted: (_) => submit(),
+          decoration: .new(
+            labelText: "Server name",
+            hintText: "matrix.org",
+            errorText: error,
+          ),
+        ),
+      ],
+    );
+  }
+}

lib/widgets/invites_list.dart

@@ -3,8 +3,8 @@ import "package:material_ui/material_ui.dart";
 import "package:material_adaptive_sheets/material_adaptive_sheets.dart";
 import "package:nexus/controllers/invites.dart";
 import "package:nexus/helpers/extensions/get_localpart.dart";
+import "package:nexus/helpers/extensions/room_summary_display.dart";
 import "package:nexus/main.dart";
-import "package:nexus/models/content/create.dart";
 import "package:nexus/models/nav_page.dart";
 import "package:nexus/models/room_summary.dart";
 import "package:nexus/widgets/avatar_or_hash.dart";
@@ -120,13 +120,7 @@ class const InviteCard(final RoomSummary invite, {super.key})
           invite.avatarUrl,
           name,
           dimension: 40,
-          fallback: invite.isDirect
+          fallback: invite.isDirect ? null : Icon(invite.icon),
-              ? null
-              : Icon(
-                  invite.roomType == RoomType.space
-                      ? Icons.workspaces
-                      : Icons.numbers,
-                ),
         ),
         title: Text(name, maxLines: 1, overflow: .ellipsis),
         subtitle: Text(

lib/widgets/m3e_rail_theme.dart

@@ -0,0 +1,36 @@
+import "package:material_ui/material_ui.dart";
+import "package:m3e_design/m3e_design.dart";
+
+// Needed for navigation_rail_m3e (#65).
+import "package:flutter/material.dart" as old_mat;
+
+/// Themes a navigation_rail_m3e rail, which still uses the old Material theme.
+class const M3ERailTheme({
+  required final WidgetBuilder builder,
+  final List<old_mat.ThemeExtension> extensions = const [],
+  super.key,
+}) extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) => MaterialUiCompatibilityBridge(
+    child: Builder(
+      builder: (context) {
+        final theme = old_mat.Theme.of(context);
+        return old_mat.Theme(
+          data: theme.copyWith(
+            extensions: [
+              ...extensions,
+              // Otherwise the FAB label falls back to Roboto
+              M3ETheme.defaults(theme.colorScheme).copyWith(
+                typography: .defaultFor(
+                  theme.brightness,
+                  baseOverride: theme.textTheme,
+                ),
+              ),
+            ],
+          ),
+          child: Builder(builder: builder),
+        );
+      },
+    ),
+  );
+}

lib/widgets/pages/explore.dart

@@ -0,0 +1,338 @@
+import "dart:math";
+
+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:material_adaptive_sheets/material_adaptive_sheets.dart";
+import "package:navigation_rail_m3e/navigation_rail_m3e.dart";
+import "package:nexus/controllers/client.dart";
+import "package:nexus/controllers/client_state.dart";
+import "package:nexus/controllers/room_directory.dart";
+import "package:nexus/controllers/rooms.dart";
+import "package:nexus/controllers/settings.dart";
+import "package:nexus/helpers/extensions/get_localpart.dart";
+import "package:nexus/main.dart";
+import "package:nexus/helpers/extensions/room_summary_display.dart";
+import "package:nexus/widgets/add_directory_server_sheet.dart";
+import "package:nexus/widgets/avatar_or_hash.dart";
+import "package:nexus/widgets/room_summary_sheet.dart";
+import "package:nexus/widgets/divider_text.dart";
+import "package:nexus/widgets/error_dialog.dart";
+import "package:nexus/widgets/loading.dart";
+import "package:nexus/widgets/m3e_rail_theme.dart";
+import "package:nexus/widgets/room_directory_card.dart";
+
+class const ExplorePage({super.key}) extends HookConsumerWidget {
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final ownServer = ref.watch(
+      ClientStateController.provider.select(
+        (state) => state?.userId?.serverName,
+      ),
+    );
+    final savedServers = ref
+        .watch(
+          SettingsController.provider.select(
+            (settings) => settings.value?.directoryServers,
+          ),
+        )
+        ?.where((server) => server != ownServer)
+        .toIList();
+
+    // Null is the user's own server
+    final selected = useState<String?>(null);
+    final servers = IList<String?>([null, ...?savedServers]);
+    String labelOf(String? server) => server ?? ownServer ?? "Home";
+    IconData iconOf(String? server) => server == null ? Icons.home : Icons.dns;
+
+    final current = servers[max(0, servers.indexOf(selected.value))];
+    final provider = RoomDirectoryController.provider(current);
+    final loadMore = RoomDirectoryController.loadMoreMutation(current);
+    final loadingMore = ref.watch(loadMore).isPending;
+    final directory = ref.watch(provider);
+    final theme = Theme.of(context);
+
+    final via = IList([?current ?? ownServer]);
+
+    Future<void> addServer() async {
+      final server = await context.showAdaptiveSheet<String>(
+        (_) => AddDirectoryServerSheet(
+          existing: .new([?ownServer, ...servers.nonNulls]),
+        ),
+      );
+      if (server == null) return;
+
+      final settings = await ref.read(SettingsController.provider.future);
+      await ref
+          .read(SettingsController.provider.notifier)
+          .set(
+            settings.copyWith(
+              directoryServers: settings.directoryServers.add(server),
+            ),
+          );
+      if (context.mounted) selected.value = server;
+    }
+
+    Future<void> removeServer(String server) async {
+      selected.value = null;
+      final settings = await ref.read(SettingsController.provider.future);
+      await ref
+          .read(SettingsController.provider.notifier)
+          .set(
+            settings.copyWith(
+              directoryServers: settings.directoryServers.remove(server),
+            ),
+          );
+    }
+
+    return LayoutBuilder(
+      builder: (context, constraints) {
+        final isWide = constraints.maxWidth >= 700;
+
+        final searchBar = SearchAnchor.bar(
+          barHintText: "Search...",
+          isFullScreen: !isWide,
+          suggestionsBuilder: (suggestionsContext, controller) async {
+            final text = controller.text.trim();
+            if (text.isEmpty) return const [];
+
+            // Each search hits the server, so wait for the user to stop typing
+            await Future.delayed(Durations.long2);
+            if (controller.text.trim() != text) return const [];
+
+            try {
+              final directory = await ref
+                  .read(ClientController.provider.notifier)
+                  .getRoomDirectory(
+                    .new(
+                      server: current,
+                      limit: 20,
+                      filter: .new(genericSearchTerm: text),
+                    ),
+                  );
+              return directory.rooms.map(
+                (summary) => Consumer(
+                  builder: (_, ref, _) {
+                    final joined = ref.watch(
+                      RoomsController.provider.select(
+                        (rooms) => rooms.containsKey(summary.roomId),
+                      ),
+                    );
+
+                    return ListTile(
+                      onTap: () {
+                        Navigator.of(suggestionsContext).pop();
+                        controller.text = "";
+
+                        context.showAdaptiveSheet(
+                          (_) => RoomSummarySheet(
+                            summary,
+                            via: joined ? null : via,
+                          ),
+                        );
+                      },
+                      leading: AvatarOrHash(
+                        summary.avatarUrl,
+                        summary.displayName,
+                        fallback: Icon(summary.icon),
+                      ),
+                      title: Text(summary.displayName),
+                      subtitle: Text(
+                        [
+                          summary.details,
+                          if (joined) "Joined",
+                        ].where((part) => part.isNotEmpty).join(" · "),
+                      ),
+                    );
+                  },
+                ),
+              );
+            } catch (error) {
+              return [
+                ListTile(
+                  leading: const Icon(Icons.error_outline),
+                  title: const Text("Couldn't search this server"),
+                  subtitle: Text(error.toString()),
+                ),
+              ];
+            }
+          },
+        );
+
+        final results = CustomScrollView(
+          slivers: [
+            SliverPadding(
+              padding: const .all(16),
+              sliver: SliverList.list(
+                children: [
+                  if (!isWide)
+                    Padding(
+                      padding: const .only(bottom: 12),
+                      child: SingleChildScrollView(
+                        scrollDirection: .horizontal,
+                        child: Row(
+                          spacing: 8,
+                          children: [
+                            ...servers.map(
+                              (server) => ChoiceChip(
+                                avatar: Icon(iconOf(server)),
+                                label: Text(labelOf(server)),
+                                selected: current == server,
+                                onSelected: (_) => selected.value = server,
+                              ),
+                            ),
+                            ActionChip(
+                              avatar: const Icon(Icons.add),
+                              label: const Text("Add server"),
+                              onPressed: () => addServer().onError(showError),
+                            ),
+                          ],
+                        ),
+                      ),
+                    ),
+                  searchBar,
+                  const SizedBox(height: 16),
+                  Text(switch (directory.value?.totalRoomCountEstimate) {
+                    final count? when count > 0 => "Popular Rooms ($count)",
+                    _ => "Popular Rooms",
+                  }, style: theme.textTheme.titleLarge),
+                ],
+              ),
+            ),
+            ...switch (directory) {
+              AsyncData(:final value) when value.rooms.isEmpty => [
+                SliverFillRemaining(
+                  hasScrollBody: false,
+                  child: Center(
+                    child: Column(
+                      mainAxisSize: .min,
+                      children: [
+                        Icon(
+                          Icons.search_off,
+                          size: 48,
+                          color: theme.colorScheme.onSurface,
+                        ),
+                        const SizedBox(height: 12),
+                        Text(
+                          "No rooms found",
+                          style: theme.textTheme.headlineSmall,
+                        ),
+                      ],
+                    ),
+                  ),
+                ),
+              ],
+              AsyncData(:final value) || AsyncLoading(:final value?) => [
+                SliverPadding(
+                  padding: const .symmetric(horizontal: 16),
+                  sliver: SliverLayoutBuilder(
+                    builder: (_, constraints) => SliverGrid.builder(
+                      gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
+                        crossAxisCount: max(
+                          1,
+                          (constraints.crossAxisExtent + 12) ~/ (280 + 12),
+                        ),
+                        mainAxisExtent: 210,
+                        crossAxisSpacing: 12,
+                        mainAxisSpacing: 12,
+                      ),
+                      itemCount: value.rooms.length,
+                      itemBuilder: (_, index) =>
+                          RoomDirectoryCard(value.rooms[index], via: via),
+                    ),
+                  ),
+                ),
+                SliverPadding(
+                  padding: const .all(16),
+                  sliver: SliverToBoxAdapter(
+                    child: value.nextBatch == null
+                        ? null
+                        : Center(
+                            child: TextButton(
+                              onPressed: loadingMore
+                                  ? null
+                                  : () => loadMore
+                                        .run(
+                                          ref,
+                                          (transaction) => transaction
+                                              .get(provider.notifier)
+                                              .loadMore(),
+                                        )
+                                        .onError(showError),
+                              child: const Text("Load more"),
+                            ),
+                          ),
+                  ),
+                ),
+              ],
+              AsyncError(:final error, :final stackTrace) => [
+                SliverFillRemaining(
+                  hasScrollBody: false,
+                  child: ErrorDialog(error, stackTrace, provider: provider),
+                ),
+              ],
+              AsyncLoading() => [
+                const SliverFillRemaining(
+                  hasScrollBody: false,
+                  child: Loading(),
+                ),
+              ],
+            },
+          ],
+        );
+
+        return Scaffold(
+          appBar: AppBar(
+            title: const Text("Explore Rooms"),
+            actionsPadding: const .symmetric(horizontal: 12),
+            actions: [
+              if (current case final server?)
+                IconButton(
+                  tooltip: "Remove server",
+                  onPressed: () => removeServer(server).onError(showError),
+                  icon: const Icon(Icons.delete_outline),
+                ),
+            ],
+          ),
+          body: isWide
+              ? Row(
+                  children: [
+                    M3ERailTheme(
+                      builder: (_) => NavigationRailM3E(
+                        type: .alwaysExpand,
+                        scrollable: true,
+                        fab: .new(
+                          icon: const Icon(Icons.add),
+                          label: "Add server",
+                          tooltip: "Add a server to browse",
+                          onPressed: () => addServer().onError(showError),
+                        ),
+                        sections: [
+                          .new(
+                            header: const DividerText("Servers"),
+                            destinations: servers
+                                .map(
+                                  (server) => NavigationRailM3EDestination(
+                                    icon: Icon(iconOf(server)),
+                                    label: labelOf(server),
+                                  ),
+                                )
+                                .toList(),
+                          ),
+                        ],
+                        selectedIndex: servers.indexOf(current),
+                        onDestinationSelected: (index) =>
+                            selected.value = servers[index],
+                      ),
+                    ),
+                    const VerticalDivider(),
+                    Expanded(child: results),
+                  ],
+                )
+              : results,
+        );
+      },
+    );
+  }
+}

lib/widgets/room_directory_card.dart

@@ -0,0 +1,130 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:hooks_riverpod/hooks_riverpod.dart";
+import "package:material_ui/material_ui.dart";
+import "package:material_adaptive_sheets/material_adaptive_sheets.dart";
+import "package:nexus/controllers/rooms.dart";
+import "package:nexus/controllers/sidebar_page.dart";
+import "package:nexus/helpers/extensions/focus_room.dart";
+import "package:nexus/helpers/extensions/join_room.dart";
+import "package:nexus/helpers/extensions/room_summary_display.dart";
+import "package:nexus/models/room_summary.dart";
+import "package:nexus/widgets/avatar_or_hash.dart";
+import "package:nexus/widgets/knock_sheet.dart";
+import "package:nexus/widgets/room_summary_sheet.dart";
+
+class const RoomDirectoryCard(
+  final RoomSummary summary, {
+  required final IList<String> via,
+  super.key,
+}) extends ConsumerWidget {
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final joined = ref.watch(
+      RoomsController.provider.select(
+        (rooms) => rooms.containsKey(summary.roomId),
+      ),
+    );
+    final mustKnock = ref.watch(
+      RoomsController.provider.select(
+        (rooms) => summary.mustKnock(
+          summary.allowedRoomIds.where(rooms.containsKey).toISet(),
+        ),
+      ),
+    );
+    final theme = Theme.of(context);
+    final name = summary.displayName;
+
+    return Card.filled(
+      clipBehavior: .antiAlias,
+      margin: .zero,
+      child: InkWell(
+        onTap: () => context.showAdaptiveSheet(
+          (_) => RoomSummarySheet(summary, via: joined ? null : via),
+        ),
+        child: Padding(
+          padding: const .all(16),
+          child: Column(
+            crossAxisAlignment: .stretch,
+            spacing: 12,
+            children: [
+              Row(
+                spacing: 12,
+                children: [
+                  AvatarOrHash(
+                    summary.avatarUrl,
+                    name,
+                    dimension: 48,
+                    fallback: Icon(summary.icon),
+                  ),
+                  Expanded(
+                    child: Column(
+                      crossAxisAlignment: .start,
+                      children: [
+                        Text(
+                          name,
+                          maxLines: 1,
+                          overflow: .ellipsis,
+                          style: theme.textTheme.titleMedium,
+                        ),
+                        if (summary.details case final details
+                            when details.isNotEmpty)
+                          Text(
+                            details,
+                            maxLines: 1,
+                            overflow: .ellipsis,
+                            style: theme.textTheme.bodySmall?.copyWith(
+                              color: theme.colorScheme.onSurfaceVariant,
+                            ),
+                          ),
+                      ],
+                    ),
+                  ),
+                ],
+              ),
+              Expanded(
+                child: Text(
+                  summary.topic ?? summary.canonicalAlias ?? "",
+                  maxLines: 3,
+                  overflow: .ellipsis,
+                  style: theme.textTheme.bodyMedium?.copyWith(
+                    color: theme.colorScheme.onSurfaceVariant,
+                  ),
+                ),
+              ),
+              Align(
+                alignment: .centerRight,
+                child: joined
+                    ? FilledButton.tonal(
+                        onPressed: () async {
+                          final container = ProviderScope.containerOf(context);
+                          Navigator.of(context).pop();
+                          await container.focusRoom(summary.roomId);
+                          container
+                              .read(SidebarPageController.provider.notifier)
+                              .set(.rooms);
+                        },
+                        child: const Text("Open"),
+                      )
+                    : mustKnock
+                    ? FilledButton(
+                        onPressed: () => context.showAdaptiveSheet(
+                          (_) =>
+                              KnockSheet(summary.roomId, name: name, via: via),
+                        ),
+                        child: const Text("Knock"),
+                      )
+                    : FilledButton(
+                        onPressed: () => context.joinRoom(
+                          .new(roomIdOrAlias: summary.roomId, via: via),
+                          name: name,
+                        ),
+                        child: const Text("Join"),
+                      ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/widgets/room_list.dart

@@ -3,7 +3,6 @@ import "dart:math";
 import "package:fast_immutable_collections/fast_immutable_collections.dart";
 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:material_adaptive_sheets/material_adaptive_sheets.dart";
 import "package:nexus/helpers/extensions/get_all_child_rooms.dart";
@@ -17,8 +16,10 @@ import "package:nexus/widgets/create_room_sheet.dart";
 import "package:nexus/widgets/start_dm_sheet.dart";
 import "package:nexus/widgets/divider_widget.dart";
 import "package:nexus/widgets/error_dialog.dart";
+import "package:nexus/widgets/pages/explore.dart";
 import "package:nexus/widgets/pages/settings.dart";
 import "package:nexus/widgets/join_sheet.dart";
+import "package:nexus/widgets/m3e_rail_theme.dart";
 import "package:nexus/widgets/room_summary_sheet.dart";
 import "package:nexus/widgets/room_menu_button.dart";
 import "package:nexus/widgets/space_hierarchy_sheet.dart";
@@ -28,9 +29,6 @@ import "package:nexus/controllers/selected_space.dart";
 import "package:nexus/controllers/rooms.dart";
 import "package:nexus/controllers/spaces.dart";
 
-// Needed for navigation_rail_m3e (#65).
-import "package:flutter/material.dart" as old_mat;
-
 class const RoomList({super.key}) extends ConsumerWidget implements NavPage {
   @override
   String get title => "Rooms";
@@ -92,18 +90,11 @@ class const SpacesRail({super.key}) extends ConsumerWidget {
           .select((async) => async.requireValue),
     );
 
-    return MaterialUiCompatibilityBridge(
+    return M3ERailTheme(
-      child: Builder(
-        builder: (context) => old_mat.Theme(
-          data: old_mat.Theme.of(context).copyWith(
       extensions: [
-              NavigationRailM3ETheme(
+        NavigationRailM3ETheme(itemCollapsedHeight: 48, itemVerticalGap: 0),
-                itemCollapsedHeight: 48,
-                itemVerticalGap: 0,
-              ),
       ],
-          ),
+      builder: (context) => Container(
-          child: Container(
         color: NavigationRailTokensAdapter(context).containerColor,
         padding: .only(top: 16),
         child: NavigationRailM3E(
@@ -112,14 +103,10 @@ class const SpacesRail({super.key}) extends ConsumerWidget {
           scrollable: true,
           onDestinationSelected: (value) {
             ref
-                    .read(
+                .read(KeyController.provider(KeyController.spaceKey).notifier)
-                      KeyController.provider(KeyController.spaceKey).notifier,
-                    )
                 .set(spaces[value].id);
             ref
-                    .read(
+                .read(KeyController.provider(KeyController.roomKey).notifier)
-                      KeyController.provider(KeyController.roomKey).notifier,
-                    )
                 .set(spaces[value].children.firstOrNull?.metadata?.id);
           },
           sections: [
@@ -193,10 +180,12 @@ class const SpacesRail({super.key}) extends ConsumerWidget {
                   icon: const Icon(Icons.add),
                 ),
                 const AccountSwitcher(),
-                    const IconButton(
+                IconButton(
-                      tooltip: "Explore other rooms (Not yet implemented)",
+                  tooltip: "Explore other rooms",
-                      onPressed: null,
+                  onPressed: () => Navigator.of(context).push(
-                      icon: Icon(Icons.explore),
+                    MaterialPageRoute(builder: (_) => const ExplorePage()),
+                  ),
+                  icon: const Icon(Icons.explore),
                 ),
                 IconButton(
                   tooltip: "Open settings",
@@ -211,8 +200,6 @@ class const SpacesRail({super.key}) extends ConsumerWidget {
           ),
         ),
       ),
-        ),
-      ),
     );
   }
 }
@@ -254,28 +241,15 @@ class const RoomsPane({super.key}) extends ConsumerWidget {
           ),
         ]),
       ),
-      body: MaterialUiCompatibilityBridge(
+      body: M3ERailTheme(
-        child: Builder(
-          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,
-                    ),
-                  ),
         ],
-              ),
+        builder: (context) => Padding(
-              child: Padding(
           padding: const .only(top: 4),
           child: NavigationRailM3E(
             fab: selectedSpace.room == null
@@ -309,9 +283,7 @@ class const RoomsPane({super.key}) extends ConsumerWidget {
                 header: selectedSpace.room == null
                     ? null
                     : const DividerWidget(Text("Rooms")),
-                      destinations: selectedSpace.children.toDestinations(
+                destinations: selectedSpace.children.toDestinations(isDm: isDm),
-                        isDm: isDm,
-                      ),
               ),
               ...selectedSpace.subSpaces.map(
                 (subSpace) => NavigationRailM3ESection(
@@ -323,14 +295,12 @@ class const RoomsPane({super.key}) extends ConsumerWidget {
                         if (subSpace.room.metadata?.avatar != null)
                           AvatarOrHash(
                             subSpace.room.metadata?.avatar,
-                                  subSpace.room.metadata?.name ??
+                            subSpace.room.metadata?.name ?? "Unnamed Room",
-                                      "Unnamed Room",
                             dimension: 16,
                           ),
                         Flexible(
                           child: Text(
-                                  subSpace.room.metadata?.name ??
+                            subSpace.room.metadata?.name ?? "Unnamed Space",
-                                      "Unnamed Space",
                             maxLines: 1,
                             overflow: .ellipsis,
                           ),
@@ -338,18 +308,13 @@ class const RoomsPane({super.key}) extends ConsumerWidget {
                       ],
                     ),
                   ),
-                        destinations: subSpace.children.toDestinations(
+                  destinations: subSpace.children.toDestinations(isDm: isDm),
-                          isDm: isDm,
-                        ),
                 ),
               ),
             ],
             onDestinationSelected: (value) {
               ref
-                        .read(
+                  .read(KeyController.provider(KeyController.roomKey).notifier)
-                          KeyController.provider(KeyController.roomKey)
-                              .notifier,
-                        )
                   .set(destinationIds[value]);
               if (Navigator.of(context).canPop()) {
                 Navigator.of(context).pop();
@@ -357,9 +322,6 @@ class const RoomsPane({super.key}) extends ConsumerWidget {
             },
           ),
         ),
-            );
-          },
-        ),
       ),
     );
   }

lib/widgets/room_summary_sheet.dart

@@ -7,6 +7,7 @@ import "package:nexus/controllers/invites.dart";
 import "package:nexus/controllers/rooms.dart";
 import "package:nexus/helpers/extensions/get_localpart.dart";
 import "package:nexus/helpers/extensions/join_room.dart";
+import "package:nexus/helpers/extensions/room_summary_display.dart";
 import "package:nexus/main.dart";
 import "package:nexus/widgets/avatar_or_hash.dart";
 import "package:nexus/widgets/expandable_image.dart";
@@ -44,15 +45,11 @@ class const RoomSummarySheet(
                 summary.avatarUrl,
                 "",
                 dimension: 64,
-                fallback: Icon(Icons.numbers),
+                fallback: Icon(summary.icon),
               ),
             ),
           Expanded(
-            child: Text(
+            child: Text(summary.displayName, overflow: .ellipsis, maxLines: 3),
-              summary.name ?? summary.canonicalAlias ?? "Unnamed Room",
-              overflow: .ellipsis,
-              maxLines: 3,
-            ),
           ),
         ],
       ),

lib/widgets/settings/settings_layout.dart

@@ -12,6 +12,7 @@ import "package:nexus/models/settings_category.dart";
 import "package:nexus/widgets/pages/settings_category.dart";
 import "package:nexus/widgets/divider_text.dart";
 import "package:nexus/widgets/highlight_wrapper.dart";
+import "package:nexus/widgets/m3e_rail_theme.dart";
 import "package:super_sliver_list/super_sliver_list.dart";
 
 /// A settings screen split into categories: a list of them that opens each
@@ -170,8 +171,8 @@ class const SettingsLayout({
                       )
                     : Row(
                         children: [
-                          MaterialUiCompatibilityBridge(
+                          M3ERailTheme(
-                            child: NavigationRailM3E(
+                            builder: (_) => NavigationRailM3E(
                               type: .alwaysExpand,
                               trailing: searchBar,
                               scrollable: true,

lib/widgets/space_hierarchy_sheet.dart

@@ -10,6 +10,7 @@ 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/room_summary_display.dart";
 import "package:nexus/helpers/extensions/show_leave_room_sheet.dart";
 import "package:nexus/helpers/extensions/with_progress_snackbar.dart";
 import "package:nexus/main.dart";
@@ -163,10 +164,7 @@ class const SpaceHierarchySheet(final String spaceId, {super.key})
           keyMapper: (room) => room.summary.roomId,
           values: hierarchy.rooms,
         );
-        final spaceName =
+        final spaceName = byId[spaceId]?.summary.displayName ?? "Unnamed Space";
-            byId[spaceId]?.summary.name ??
-            byId[spaceId]?.summary.canonicalAlias ??
-            "Unnamed Space";
         final children = (byId[spaceId]?.children ?? const .empty())
             .map(
               (child) => switch (byId[child.roomId]) {
@@ -197,16 +195,13 @@ class const SpaceHierarchySheet(final String spaceId, {super.key})
                 Builder(
                   builder: (context) {
                     final summary = room.summary;
-                    final name =
+                    final name = summary.displayName;
-                        summary.name ??
-                        summary.canonicalAlias ??
-                        "Unnamed Room";
 
                     return ListTile(
                       leading: AvatarOrHash(
                         summary.avatarUrl,
                         name,
-                        fallback: const Icon(Icons.numbers),
+                        fallback: Icon(summary.icon),
                       ),
                       title: Text(name, maxLines: 1, overflow: .ellipsis),
                       subtitle: summary.topic == null
@@ -239,10 +234,7 @@ class const SpaceHierarchySheet(final String spaceId, {super.key})
                   builder: (context, ref, _) {
                     final expanded = useState(false);
                     final summary = room.summary;
-                    final name =
+                    final name = summary.displayName;
-                        summary.name ??
-                        summary.canonicalAlias ??
-                        "Unnamed Space";
                     final joined = joinedIds.contains(summary.roomId);
 
                     return Column(
@@ -255,7 +247,7 @@ class const SpaceHierarchySheet(final String spaceId, {super.key})
                           leading: AvatarOrHash(
                             summary.avatarUrl,
                             name,
-                            fallback: const Icon(Icons.workspaces),
+                            fallback: Icon(summary.icon),
                           ),
                           title: Text(name, maxLines: 1, overflow: .ellipsis),
                           subtitle: summary.topic == null
@@ -390,7 +382,7 @@ class const SpaceHierarchySheet(final String spaceId, {super.key})
                     ),
                   Expanded(
                     child: Text(
-                      space?.name ?? space?.canonicalAlias ?? "Unnamed Space",
+                      space?.displayName ?? "Unnamed Space",
                       overflow: .ellipsis,
                       maxLines: 3,
                     ),