Build exchange workspace and shared transaction services (#28)

frontend/app/lib/providers/locale.dart

@@ -2,12 +2,15 @@ import 'package:flutter/material.dart';
 
 import 'package:shared_preferences/shared_preferences.dart';
 
+import 'package:sxchnge_wallet/sxchnge_wallet.dart';
+
 class LocaleProvider extends ChangeNotifier {
   static const storageKey = 'sxchnge_last_locale';
   LocaleProvider({Locale initialLocale = const Locale('en'), this.preferences})
     : _locale = resolve(initialLocale.languageCode, const []);
 
   Locale _locale;
+  bool _disposed = false;
   final SharedPreferences? preferences;
   Future<bool> _pendingSave = Future.value(true);
   Locale get locale => _locale;
@@ -31,6 +34,22 @@ class LocaleProvider extends ChangeNotifier {
     }
   }
 
+  Future<void> loadAccount(WalletProvider wallet) async {
+    await wallet.loadProfile();
+    if (_disposed) return;
+    if (wallet.preferredLocale != null && !wallet.profileFailed) {
+      _locale = resolve(wallet.preferredLocale, const []);
+      notifyListeners();
+    }
+  }
+
+  Future<void> saveAccountLocale(WalletProvider wallet, Locale value) async {
+    if (_disposed || wallet.saving) return;
+    _locale = resolve(value.languageCode, const []);
+    notifyListeners();
+    await wallet.saveLocale(_locale.languageCode);
+  }
+
   Future<bool> setLocale(Locale value) {
     final next = resolve(value.languageCode, const []);
     if (next == _locale) return _pendingSave;
@@ -47,4 +66,10 @@ class LocaleProvider extends ChangeNotifier {
     });
     return _pendingSave;
   }
+
+  @override
+  void dispose() {
+    _disposed = true;
+    super.dispose();
+  }
 }