OAuth Support (#53)

Rips out the old auth method, adds OAuth support. Fixes #51.

Tested Platforms:
- [x] Linux
    - [x] Flatpak
    - [x] Native (Nix)
- [x] Android
- [ ] Windows
- [ ] MacOS

Reviewed-on: Nexus/nexus#53

lib/controllers/auth_url.dart

@@ -0,0 +1,32 @@
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:nexus/controllers/client.dart";
+import "package:nexus/controllers/client_id.dart";
+import "package:nexus/models/oauth_auth_code_response.dart";
+import "package:nexus/models/requests/oauth/get_auth_url.dart";
+
+class AuthUrlController extends AsyncNotifier<OAuthAuthCodeResponse> {
+  final Uri homeserver;
+  AuthUrlController(this.homeserver);
+
+  @override
+  Future<OAuthAuthCodeResponse> build() async => ref
+      .watch(ClientController.provider.notifier)
+      .getAuthUrl(
+        .new(
+          homeserverUrl: homeserver,
+          redirectUri: .new(scheme: "nexus.federated.nexus", path: "/"),
+          responseMode: .query,
+          scopes: .new([Scope.clientApi, Scope.device]),
+          clientId: await ref.watch(
+            ClientIdController.provider(homeserver).future,
+          ),
+        ),
+      );
+
+  static final provider =
+      AsyncNotifierProvider.family<
+        AuthUrlController,
+        OAuthAuthCodeResponse,
+        Uri
+      >(AuthUrlController.new);
+}

lib/controllers/client.dart

@@ -15,13 +15,16 @@ import "package:nexus/controllers/top_level_spaces.dart";
 import "package:nexus/helpers/extensions/gomuks_buffer.dart";
 import "package:nexus/main.dart";
 import "package:nexus/models/event.dart";
+import "package:nexus/models/oauth_auth_code_response.dart";
 import "package:nexus/models/paginate.dart";
 import "package:nexus/models/requests/get_event.dart";
 import "package:nexus/models/requests/get_related_events.dart";
 import "package:nexus/models/requests/get_room_state.dart";
 import "package:nexus/models/requests/join_room.dart";
-import "package:nexus/models/requests/login.dart";
 import "package:nexus/models/profile.dart";
+import "package:nexus/models/requests/oauth/exchange_token.dart";
+import "package:nexus/models/requests/oauth/get_auth_url.dart";
+import "package:nexus/models/requests/oauth/register_client.dart";
 import "package:nexus/models/requests/paginate.dart";
 import "package:nexus/models/requests/redact_event.dart";
 import "package:nexus/models/requests/report.dart";
@@ -263,6 +266,8 @@ class ClientController extends AsyncNotifier<int> {
   Future<void> setMembership(SetMembershipRequest request) =>
       _sendCommand("set_membership", request.toJson());
 
+  Future<void> logout() => _sendCommand("logout");
+
   Future<void> markRead(Room room) async {
     final eventRowId = room.timeline[room.timeline.keys.reduce(max)];
     final event = eventRowId == null ? null : room.events[eventRowId];
@@ -275,14 +280,19 @@ class ClientController extends AsyncNotifier<int> {
     });
   }
 
-  Future<String?> login(LoginRequest login) async {
-    try {
-      await _sendCommand("login", login.toJson());
-      return null;
-    } catch (error) {
-      return error.toString();
-    }
-  }
+  Future<String> registerClient(OAuthRegisterClientRequest request) async =>
+      (await _sendCommand(
+        "oauth_register_client",
+        request.toJson(),
+      ))["client_id"];
+
+  Future<OAuthAuthCodeResponse> getAuthUrl(OAuthGetAuthUrl request) async =>
+      .fromJson(
+        await _sendCommand("oauth_get_authorization_url", request.toJson()),
+      );
+
+  Future<void> exchangeToken(OAuthExchangeTokenRequest request) async =>
+      await _sendCommand("oauth_exchange_token", request.toJson());
 
   Future<Uri?> discoverHomeserver(Uri homeserver) async {
     try {

lib/controllers/client_id.dart

@@ -0,0 +1,33 @@
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:nexus/controllers/client.dart";
+
+class ClientIdController extends AsyncNotifier<String> {
+  final Uri homeserver;
+  ClientIdController(this.homeserver);
+
+  @override
+  Future<String> build() => ref
+      .watch(ClientController.provider.notifier)
+      .registerClient(
+        .new(
+          clientName: "Nexus",
+          applicationType: .native,
+          grantTypes: .new([.authorizationCode, .refreshToken]),
+          responseTypes: .new([.code]),
+          logoUri: Uri.https(
+            "nexus.federated.nexus",
+            "raw/branch/main/assets/mobile.svg",
+          ),
+          homeserverUrl: homeserver,
+          clientUri: Uri.https("nexus.federated.nexus"),
+          redirectUris: .new([
+            .new(scheme: "nexus.federated.nexus", path: "/"),
+          ]),
+        ),
+      );
+
+  static final provider =
+      AsyncNotifierProvider.family<ClientIdController, String, Uri>(
+        ClientIdController.new,
+      );
+}

lib/controllers/settings_sections.dart

@@ -3,6 +3,8 @@ import "package:fast_immutable_collections/fast_immutable_collections.dart";
 import "package:flutter/material.dart";
 import "package:flutter_riverpod/flutter_riverpod.dart";
 import "package:intl/intl.dart";
+import "package:m3e_buttons/m3e_buttons.dart";
+import "package:nexus/controllers/client.dart";
 import "package:nexus/controllers/settings.dart";
 import "package:nexus/models/settings_category.dart";
 import "package:nexus/main.dart";
@@ -87,11 +89,46 @@ class SettingsSectionsController
           ]),
         ),
       ]),
+      "Account": .new([
+        .new(title: "Profile", icon: Icons.person, settings: .new([])),
+        .new(
+          title: "Other",
+          icon: Icons.key,
+          settings: .new([
+            .new(
+              title: "Log Out",
+              description:
+                  "Log out of your account, returning you to the login page.",
+              builder: (title, description, icon) => Builder(
+                builder: (context) {
+                  final colorScheme = Theme.of(context).colorScheme;
+                  return M3EButton.icon(
+                    onPressed: () async {
+                      await ref
+                          .watch(ClientController.provider.notifier)
+                          .logout();
+                      if (context.mounted) Navigator.of(context).pop();
+                    },
+                    label: Text(title),
+                    icon: Icon(icon),
+                    tooltip: description,
+                    decoration: .styleFrom(
+                      backgroundColor: colorScheme.errorContainer,
+                      foregroundColor: colorScheme.onErrorContainer,
+                    ),
+                  );
+                },
+              ),
+              icon: Icons.logout,
+            ),
+          ]),
+        ),
+      ]),
     });
   }
 
   static final provider =
-      AsyncNotifierProvider<
+      AsyncNotifierProvider.autoDispose<
         SettingsSectionsController,
         IMap<String, IList<SettingsCategory>>
       >(SettingsSectionsController.new);