nexus/lib/pages/select_server.dart

import "package:app_links/app_links.dart";
import "package:flutter/material.dart";
import "package:flutter_hooks/flutter_hooks.dart";
import "package:flutter_svg/flutter_svg.dart";
import "package:hooks_riverpod/hooks_riverpod.dart";
import "package:nexus/controllers/auth_url.dart";
import "package:nexus/controllers/client.dart";
import "package:nexus/controllers/client_id.dart";
import "package:nexus/helpers/launch_helper.dart";
import "package:nexus/main.dart";
import "package:nexus/models/homeserver.dart";
import "package:nexus/pages/settings.dart";
import "package:nexus/widgets/appbar.dart";
import "package:nexus/widgets/divider_text.dart";

class SelectServerPage extends HookConsumerWidget {
  const SelectServerPage({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final theme = Theme.of(context);

    final launch = ref.watch(LaunchHelper.provider).launchUrl;

    final isLoading = useState(false);
    final homeserverUrl = useTextEditingController();

    Future<void> setHomeserver(Uri? newHomeserver) async {
      isLoading.value = true;

      try {
        if (newHomeserver?.hasScheme == false) {
          newHomeserver = Uri.https(newHomeserver!.path);
        }

        final newUrl = newHomeserver == null
            ? null
            : await ref
                  .read(ClientController.provider.notifier)
                  .discoverHomeserver(newHomeserver);

        if (context.mounted) {
          if (newUrl == null) {
            ScaffoldMessenger.of(context).showSnackBar(
              SnackBar(
                content: Text(
                  "Homeserver verification failed. Is your homeserver down?",
                  style: .new(color: theme.colorScheme.onErrorContainer),
                ),
                backgroundColor: theme.colorScheme.errorContainer,
              ),
            );
          } else {
            final codeResponse = await ref.watch(
              AuthUrlController.provider(newUrl).future,
            );

            await ref.watch(LaunchHelper.provider).launchUrl(codeResponse.url);

            AppLinks().uriLinkStream.listen((encodedUri) async {
              final state = encodedUri.queryParameters["state"];
              if (state != codeResponse.state) return;
              isLoading.value = true;

              try {
                final code = encodedUri.queryParameters["code"];

                if (code != null) {
                  await ref
                      .watch(ClientController.provider.notifier)
                      .exchangeToken(
                        .new(
                          homeserverUrl: newUrl,
                          codeVerifier: codeResponse.codeVerifier,
                          redirectUri: .new(
                            scheme: "nexus.federated.nexus",
                            path: "/",
                          ),
                          code: code,
                          clientId: await ref.watch(
                            ClientIdController.provider(newUrl).future,
                          ),
                        ),
                      )
                      .onError(showError);
                }
              } finally {
                isLoading.value = false;
              }
            });
          }
        }
      } catch (error, stackTrace) {
        showError(error, stackTrace);
      } finally {
        isLoading.value = false;
      }
    }

    return Scaffold(
      appBar: Appbar(
        actions: .new([
          IconButton(
            onPressed: () =>
                showDialog(context: context, builder: (_) => SettingsPage()),
            icon: Icon(Icons.settings),
          ),
        ]),
      ),
      body: SafeArea(
        child: Center(
          child: ConstrainedBox(
            constraints: .new(maxWidth: 600),
            child: ListView(
              padding: .symmetric(vertical: 8, horizontal: 12),
              children: [
                Row(
                  children: [
                    SvgPicture.asset("assets/icon.svg", width: 128),
                    SizedBox(width: 12),
                    Expanded(
                      child: Column(
                        crossAxisAlignment: .start,
                        children: [
                          Text("Nexus", style: theme.textTheme.displayMedium),
                          Text(
                            "A Simple Matrix Client",
                            style: theme.textTheme.headlineMedium,
                            overflow: .ellipsis,
                          ),
                        ],
                      ),
                    ),
                  ],
                ),
                Padding(padding: .symmetric(vertical: 12), child: Divider()),
                DividerText("Enter a homeserver domain:"),
                Row(
                  spacing: 8,
                  children: [
                    Expanded(
                      child: TextField(
                        textInputAction: .done,
                        autofocus: true,
                        onSubmitted: (text) => setHomeserver(.tryParse(text)),
                        controller: homeserverUrl,
                        decoration: .new(
                          labelText: "Homeserver URL",
                          hintText: "matrix.org",
                        ),
                      ),
                    ),
                    IconButton.filled(
                      tooltip: "Confirm homeserver choice",
                      onPressed: isLoading.value
                          ? null
                          : () => setHomeserver(.tryParse(homeserverUrl.text)),
                      icon: Icon(Icons.check),
                    ),
                  ],
                ),
                DividerText("Or, choose from some popular homeservers:"),
                ...(<Homeserver>[
                  .new(
                    name: "Matrix.org",
                    description:
                        "The Matrix.org Foundation offers the matrix.org homeserver as an easy entry point for anyone wanting to try out Matrix.",
                    url: .https("matrix.org"),
                    iconUrl:
                        "https://raw.githubusercontent.com/element-hq/logos/refs/heads/master/matrix/matrix-favicon${Theme.brightnessOf(context) == Brightness.dark ? "-white" : ""}.png",
                  ),
                  .new(
                    name: "Federated Nexus",
                    description:
                        "Federated Nexus is a community resource hosting multiple FOSS (especially federated) services, including Matrix and Forgejo. By the same developers who made Nexus client.",
                    url: .https("federated.nexus"),
                    iconUrl: "https://federated.nexus/images/icon.png",
                  ),
                  .new(
                    name: "Unredacted",
                    description:
                        "Unredacted is a 501(c)(3) non-profit organization that builds Internet infrastructure and services to help people evade censorship and protect their right to privacy.",
                    url: .https("unredacted.org", "services/si/matrix"),
                    iconUrl: "https://unredacted.org/favicon.ico",
                  ),
                ].map(
                  (homeserver) => Card(
                    child: ListTile(
                      enabled: !isLoading.value,
                      title: Text(homeserver.name),
                      leading: Image.network(
                        homeserver.iconUrl,
                        errorBuilder: (_, _, _) => SizedBox.shrink(),
                        height: 32,
                      ),
                      subtitle: Text(homeserver.description),
                      onTap: isLoading.value
                          ? null
                          : () => setHomeserver(homeserver.url),
                      trailing: IconButton(
                        tooltip: "Launch homeserver info page",
                        onPressed: () => launch(homeserver.url),
                        icon: Icon(Icons.info_outline),
                      ),
                    ),
                  ),
                )),

                TextButton(
                  onPressed: () => launch(.https("servers.joinmatrix.org")),
                  child: Text("See more homeservers..."),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}