Fix link sending

lib/controllers/via_controller.dart

@@ -0,0 +1,54 @@
+import "package:collection/collection.dart";
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:nexus/controllers/client_state_controller.dart";
+import "package:nexus/models/room.dart";
+
+class ViaController extends Notifier<String> {
+  final Room room;
+  ViaController(this.room);
+
+  @override
+  String build() {
+    final servers = <String>{};
+
+    void addUserId(String? userId) {
+      final server = userId?.split(":").lastOrNull;
+      if (server != null) {
+        servers.add(server);
+      }
+    }
+
+    addUserId(ref.watch(ClientStateController.provider)?.userId);
+
+    final powerLevels = room.events.firstWhereOrNull(
+      (event) => event.rowId == room.state["m.room.power_levels"]?[""],
+    );
+
+    for (final userId in IMap(powerLevels?.content["users"]).keys) {
+      addUserId(userId);
+      if (servers.length >= 5) break;
+    }
+
+    final members = room.state["m.room.member"]?.values.toIList();
+    for (var i = 0; servers.length < 5; i++) {
+      final member = room.events.firstWhereOrNull(
+        (event) => event.rowId == members?.getOrNull(i),
+      );
+
+      if (member?.content["membership"] == "join") {
+        addUserId(member?.stateKey);
+      }
+
+      if (members?.getOrNull(i) == null) break;
+    }
+
+    return servers.isEmpty
+        ? ""
+        : "?${servers.map((server) => "via=$server").join("&")}";
+  }
+
+  static final provider = NotifierProvider.family<ViaController, String, Room>(
+    ViaController.new,
+  );
+}