support for registering pushers

lib/controllers/unified_push.dart

@@ -0,0 +1,106 @@
+import "dart:io";
+
+import "package:flutter_riverpod/flutter_riverpod.dart";
+import "package:intl/intl.dart";
+import "package:nexus/main.dart";
+import "package:nexus/controllers/client.dart";
+import "package:nexus/controllers/client_state.dart";
+import "package:nexus/models/requests/register_pusher.dart";
+import "package:unifiedpush/unifiedpush.dart";
+import "package:unifiedpush_storage_shared_preferences/storage.dart";
+
+class UnifiedPushController extends AsyncNotifier<bool> {
+  @override
+  Future<bool> build() async {
+    final registered = await UnifiedPush.initialize(
+      linuxOptions: .new(
+        dbusName: "nexus.federated.nexus",
+        storage: UnifiedPushStorageSharedPreferences(),
+        background: isInBackground,
+      ),
+      onNewEndpoint: (endpoint, instance) async {
+        final client = ref.watch(ClientController.provider.notifier);
+        await client.registerPusher(
+          .new(
+            appDisplayName: "Nexus",
+            appId: "nexus.federated.nexus",
+            data: PusherData.webPush(
+              url: Uri.parse(endpoint.url),
+              auth: endpoint.pubKeySet!.auth,
+            ),
+            deviceDisplayName:
+                "Nexus on ${toBeginningOfSentenceCase(Platform.operatingSystem)}",
+            kind: .webPush,
+            lang: "en",
+            pushKey: endpoint.pubKeySet!.pubKey,
+          ),
+
+          // Pusher(
+          //   appDisplayName: ,
+          //   data: {
+          //     "url": endpoint.url,
+          //     "auth": endpoint.pubKeySet.auth,
+          //     "format": "event_id_only",
+          //   },
+          //   deviceDisplayName: "Nexus",
+          //   kind: "org.matrix.msc4174.webpush",
+          //   lang: WidgetsBinding.instance.platformDispatcher.locale
+          //       .toLanguageTag(),
+          //   pushkey: endpoint.pubKeySet.publicKey,
+          // ),
+        );
+      },
+      onMessage: (message, instance) async {
+        print(message);
+        // TODO: Handle incoming message
+      },
+      onRegistrationFailed: (e, r) {
+        throw "e";
+      },
+      onUnregistered: (_) {
+        throw "r";
+      },
+      onTempUnavailable: (_) {
+        throw "t";
+      },
+    );
+
+    if (registered) {
+      // Needs to be registered every startup
+      await register(true);
+    }
+
+    return registered;
+  }
+
+  Future<void> register([bool early = false]) async {
+    final clientState = ref.watch(ClientStateController.provider);
+    if (clientState?.deviceId == null) ref.invalidateSelf();
+
+    final alreadyRegistered = early ? true : await future;
+    final client = ref.watch(ClientController.provider.notifier);
+    final capabilities = await client.getCapabilities();
+
+    if (capabilities.webpush?.vapid == null) {
+      throw UnsupportedError(
+        "Your homeserver does not support MSC4174 (Web Push), and therefore cannot send notifications to Nexus.",
+      );
+    }
+
+    if (!alreadyRegistered &&
+        !await UnifiedPush.tryUseCurrentOrDefaultDistributor()) {
+      throw Exception("No UnifiedPush distributors found");
+    }
+
+    await UnifiedPush.register(
+      instance: clientState!.deviceId!,
+      vapid: capabilities.webpush?.vapid,
+    );
+
+    if (!alreadyRegistered) ref.invalidateSelf();
+  }
+
+  static final provider = AsyncNotifierProvider<UnifiedPushController, bool>(
+    UnifiedPushController.new,
+  );
+}