add inviting from room menu

lib/widgets/room_menu_button.dart

@@ -0,0 +1,146 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:material_ui/material_ui.dart";
+import "package:flutter/services.dart";
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:nexus/controllers/client.dart";
+import "package:nexus/controllers/via.dart";
+import "package:nexus/models/room.dart";
+import "package:flutter_hooks/flutter_hooks.dart";
+import "package:nexus/main.dart";
+
+final class const RoomMenuButton(
+  final Room? room, {
+  final IList<Room> children = const IList.empty(),
+  super.key,
+}) extends ConsumerWidget {
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final danger = Theme.of(context).colorScheme.error;
+    final client = ref.read(ClientController.provider.notifier);
+
+    return PopupMenuButton(
+      itemBuilder: (_) => [
+        PopupMenuItem(
+          onTap: () async {
+            if (room != null) await client.markRead(room!);
+            await Future.wait(children.map((child) => client.markRead(child)));
+          },
+          child: ListTile(
+            leading: Icon(Icons.check),
+            title: Text("Mark as Read"),
+          ),
+        ),
+        if (room != null) ...[
+          PopupMenuItem(
+            onTap: () async {
+              final vias = ref.watch(ViaController.provider(room!));
+
+              await Clipboard.setData(
+                .new(
+                  text: "matrix:roomid/${room!.metadata?.id.substring(1)}$vias",
+                ),
+              );
+            },
+            child: ListTile(
+              leading: Icon(Icons.link),
+              title: Text("Copy Link"),
+            ),
+          ),
+          PopupMenuItem(
+            onTap: () => showDialog(
+              context: context,
+              builder: (context) => HookBuilder(
+                builder: (context) {
+                  final userIdController = useTextEditingController();
+                  final text = useValueListenable(userIdController).text.trim();
+                  final valid = RegExp(r"^@[^:\s]+:[^\s]+$").hasMatch(text);
+
+                  void submit() {
+                    if (!valid) return;
+                    Navigator.of(context).pop();
+                    client
+                        .setMembership(
+                          .new(
+                            userId: text,
+                            roomId: room!.metadata!.id,
+                            action: .invite,
+                          ),
+                        )
+                        .onError(showError);
+                  }
+
+                  return AlertDialog(
+                    title: Text("Invite User"),
+                    content: TextField(
+                      controller: userIdController,
+                      autofocus: true,
+                      keyboardType: .emailAddress,
+                      onSubmitted: (_) => submit(),
+                      decoration: .new(
+                        labelText: "User ID",
+                        hintText: "@user:example.com",
+                        errorText: text.isEmpty || valid
+                            ? null
+                            : "Enter a valid user ID",
+                      ),
+                    ),
+                    actions: [
+                      TextButton(
+                        onPressed: Navigator.of(context).pop,
+                        child: Text("Cancel"),
+                      ),
+                      TextButton(
+                        onPressed: valid ? submit : null,
+                        child: Text("Invite"),
+                      ),
+                    ],
+                  );
+                },
+              ),
+            ),
+            child: ListTile(
+              leading: Icon(Icons.person_add),
+              title: Text("Invite"),
+            ),
+          ),
+          PopupMenuItem(
+            onTap: () => showDialog(
+              context: context,
+              builder: (context) => AlertDialog(
+                title: Text("Leave Room"),
+                content: Text(
+                  "Are you sure you want to leave \"${room!.metadata?.name ?? "Unnamed Room"}\"?",
+                ),
+                actions: [
+                  TextButton(
+                    onPressed: Navigator.of(context).pop,
+                    child: Text("Cancel"),
+                  ),
+                  TextButton(
+                    onPressed: () async {
+                      Navigator.of(context).pop();
+                      final snackbar = ScaffoldMessenger.of(context)
+                          .showSnackBar(
+                            .new(
+                              content: Text("Leaving room..."),
+                              duration: Duration(days: 1),
+                            ),
+                          );
+                      await client.leaveRoom(room!);
+                      snackbar.close();
+                    },
+                    child: Text("Leave"),
+                  ),
+                ],
+              ),
+            ),
+            child: ListTile(
+              leading: Icon(Icons.logout, color: danger),
+              title: Text("Leave", style: TextStyle(color: danger)),
+            ),
+          ),
+        ],
+      ],
+    );
+  }
+}