Implement FCM [WIP]

flutter/lib/state/user_account.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/foundation.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'package:simplecloudnotifier/api/api_client.dart';
+import 'package:simplecloudnotifier/models/client.dart';
 import 'package:simplecloudnotifier/models/key_token_auth.dart';
 import 'package:simplecloudnotifier/models/user.dart';
 import 'package:simplecloudnotifier/state/globals.dart';
@@ -9,10 +10,19 @@ class UserAccount extends ChangeNotifier {
   User? _user;
   User? get user => _user;
 
+  Client? _client;
+  Client? get client => _client;
+
   KeyTokenAuth? _auth;
   KeyTokenAuth? get auth => _auth;
 
-  UserAccount() {
+  static UserAccount? _singleton = UserAccount._internal();
+
+  factory UserAccount() {
+    return _singleton ?? (_singleton = UserAccount._internal());
+  }
+
+  UserAccount._internal() {
     load();
   }
 
@@ -38,6 +48,16 @@ class UserAccount extends ChangeNotifier {
     notifyListeners();
   }
 
+  void setClient(Client client) {
+    _client = client;
+    notifyListeners();
+  }
+
+  void clearClient() {
+    _client = null;
+    notifyListeners();
+  }
+
   void load() {
     final uid = Globals().sharedPrefs.getString('auth.userid');
     final tok = Globals().sharedPrefs.getString('auth.token');