improve UI of member list, sort by power level

lib/controllers/members_grouped_controller.dart

@@ -0,0 +1,49 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:nexus/controllers/members_by_status_controller.dart";
+import "package:nexus/controllers/rooms_controller.dart";
+import "package:nexus/models/configs/members_by_status_config.dart";
+import "package:nexus/models/content/content.dart";
+import "package:nexus/models/content/power_levels.dart";
+import "package:nexus/models/event.dart";
+
+class MembersGroupedController extends AsyncNotifier<IMap<int, ISet<Event>>> {
+  final MembersByStatusConfig config;
+  MembersGroupedController(this.config);
+
+  @override
+  Future<IMap<int, ISet<Event>>> build() async {
+    final event = ref.watch(
+      RoomsController.provider.select((value) {
+        final room = value[config.roomId];
+        final eventRowId = room?.state[EventType.powerLevels.type]?[""];
+        return eventRowId == null ? null : room?.events[eventRowId];
+      }),
+    );
+
+    final content = event?.content is PowerLevelsContent
+        ? event!.content as PowerLevelsContent
+        : PowerLevelsContent();
+
+    final members = await ref.watch(
+      MembersByStatusController.provider(config).future,
+    );
+
+    return members.fold<IMap<int, ISet<Event>>>(.new(), (result, event) {
+      final groupKey = content.users[event.stateKey!] ?? content.usersDefault;
+
+      return result.update(
+        groupKey,
+        (value) => value.add(event),
+        ifAbsent: () => .new({event}),
+      );
+    });
+  }
+
+  static final provider =
+      AsyncNotifierProvider.family<
+        MembersGroupedController,
+        IMap<int, ISet<Event>>,
+        MembersByStatusConfig
+      >(MembersGroupedController.new);
+}