Add subaddresses limit reached check

diff --git a/lib/l10n/app_en.arb b/lib/l10n/app_en.arb
index 27810b7..eab8391 100644
--- a/lib/l10n/app_en.arb
+++ b/lib/l10n/app_en.arb
@@ -65,6 +65,7 @@
   "receiveShowSubaddressButton": "Show Subaddress",
   "receiveShowPrimaryAddressButton": "Show Primary Address",
   "receiveServerNoSubaddressesWarn": "Warning: This server does not support subaddresses. For better privacy, consider using a server that supports them. You are receiving to your primary address.",
+  "receiveMaxSubaddressesReachedWarn": "You have reached the maximum number of subaddresses supported by this server. This is a used subaddress.",
   "sendTitle": "Send",
   "sendSendButton": "Send",
   "sendTransactionSuccessfullySent": "Transaction successfully sent!",
diff --git a/lib/l10n/app_localizations.dart b/lib/l10n/app_localizations.dart
index 16295e6..ec10393 100644
--- a/lib/l10n/app_localizations.dart
+++ b/lib/l10n/app_localizations.dart
@@ -488,6 +488,12 @@ abstract class AppLocalizations {
   /// **'Warning: This server does not support subaddresses. For better privacy, consider using a server that supports them. You are receiving to your primary address.'**
   String get receiveServerNoSubaddressesWarn;
 
+  /// No description provided for @receiveMaxSubaddressesReachedWarn.
+  ///
+  /// In en, this message translates to:
+  /// **'You have reached the maximum number of subaddresses supported by this server. This is a used subaddress.'**
+  String get receiveMaxSubaddressesReachedWarn;
+
   /// No description provided for @sendTitle.
   ///
   /// In en, this message translates to:
diff --git a/lib/l10n/app_localizations_en.dart b/lib/l10n/app_localizations_en.dart
index 34227ae..1a83180 100644
--- a/lib/l10n/app_localizations_en.dart
+++ b/lib/l10n/app_localizations_en.dart
@@ -213,6 +213,10 @@ class AppLocalizationsEn extends AppLocalizations {
   String get receiveServerNoSubaddressesWarn =>
       'Warning: This server does not support subaddresses. For better privacy, consider using a server that supports them. You are receiving to your primary address.';
 
+  @override
+  String get receiveMaxSubaddressesReachedWarn =>
+      'You have reached the maximum number of subaddresses supported by this server. This is a used subaddress.';
+
   @override
   String get sendTitle => 'Send';
 
diff --git a/lib/l10n/app_localizations_pt.dart b/lib/l10n/app_localizations_pt.dart
index d7f95d7..9d67f5d 100644
--- a/lib/l10n/app_localizations_pt.dart
+++ b/lib/l10n/app_localizations_pt.dart
@@ -213,6 +213,10 @@ class AppLocalizationsPt extends AppLocalizations {
   String get receiveServerNoSubaddressesWarn =>
       'Aviso: Este servidor não suporta subendereços. Para melhor privacidade, considere usar um servidor que os suporte. Você está recebendo no seu endereço primário.';
 
+  @override
+  String get receiveMaxSubaddressesReachedWarn =>
+      'Você atingiu o número máximo de subendereços suportados por este servidor. Este é um subendereço já usado.';
+
   @override
   String get sendTitle => 'Enviar';
 
diff --git a/lib/l10n/app_pt.arb b/lib/l10n/app_pt.arb
index cfae72b..c5ded69 100644
--- a/lib/l10n/app_pt.arb
+++ b/lib/l10n/app_pt.arb
@@ -65,6 +65,7 @@
   "receiveShowSubaddressButton": "Mostrar Subendereço",
   "receiveShowPrimaryAddressButton": "Mostrar Endereço Primário",
   "receiveServerNoSubaddressesWarn": "Aviso: Este servidor não suporta subendereços. Para melhor privacidade, considere usar um servidor que os suporte. Você está recebendo no seu endereço primário.",
+  "receiveMaxSubaddressesReachedWarn": "Você atingiu o número máximo de subendereços suportados por este servidor. Este é um subendereço já usado.",
   "sendTitle": "Enviar",
   "sendSendButton": "Enviar",
   "sendTransactionSuccessfullySent": "Transação enviada com sucesso!",
diff --git a/lib/models/wallet_model.dart b/lib/models/wallet_model.dart
index c1f2786..8ec8725 100644
--- a/lib/models/wallet_model.dart
+++ b/lib/models/wallet_model.dart
@@ -148,6 +148,8 @@ class WalletModel with ChangeNotifier {
   double? _totalBalance;
   List<TxDetails> _txHistory = [];
   bool? _serverSupportsSubaddresses;
+  int? _unusedSubaddressIndex;
+  bool? _unusedSubaddressIndexIsSupported;
 
   Wallet2Wallet? get w2Wallet => _w2Wallet;
   bool get hasAttemptedConnection => _hasAttemptedConnection;
@@ -159,6 +161,9 @@ class WalletModel with ChangeNotifier {
   List<TxDetails> get txHistory => _txHistory;
   bool get usingTor => _connectionUseTor;
   bool? get serverSupportsSubaddresses => _serverSupportsSubaddresses;
+  int? get unusedSubaddressIndex => _unusedSubaddressIndex;
+  bool? get unusedSubaddressIndexIsSupported =>
+      _unusedSubaddressIndexIsSupported;
 
   WalletModel() {
     _startTimers();
@@ -212,11 +217,13 @@ class WalletModel with ChangeNotifier {
       return;
     }
 
-    loadPersistedSubaddressSupport();
+    await loadPersistedSubaddressSupport();
+    await loadPersistedUnusedSubaddressIndex();
     await refresh();
     await loadAllStats();
     await connectToDaemon();
-    await checkSubaddressSupport();
+    await loadSubaddressSupport();
+    await loadUnusedSubaddressIndex();
   }
 
   Future<void> loadAllStats() async {
@@ -261,6 +268,10 @@ class WalletModel with ChangeNotifier {
         await persistTxHistoryCount();
       }
     }
+
+    if (txCount > _txHistory.length) {
+      await loadUnusedSubaddressIndex();
+    }
   }
 
   Future<void> persistCurrentConnection() async {
@@ -420,16 +431,84 @@ class WalletModel with ChangeNotifier {
     );
   }
 
-  Future<void> checkSubaddressSupport() async {
-    final protocol = _connectionUseSsl ? 'https' : 'http';
-    final url = Uri.parse('$protocol://$_connectionAddress/upsert_subaddrs');
+  Future<void> loadSubaddressSupport() async {
+    try {
+      final isSupported = await isSubaddressSupported(1);
+      _serverSupportsSubaddresses = isSupported;
+
+      await SharedPreferencesService.set<bool>(
+        SharedPreferencesKeys.serverSupportsSubaddresses,
+        _serverSupportsSubaddresses!,
+      );
+    } catch (e) {
+      //
+    }
+  }
+
+  Future<void> loadUnusedSubaddressIndex() async {
+    final txHistory = await _getFullTxHistory();
+
+    Set<int> usedIndexes = {};
+
+    for (final tx in txHistory) {
+      if (tx.accountIndex == 0) {
+        for (final subaddrIndex in tx.subaddrIndexList) {
+          usedIndexes.add(subaddrIndex);
+        }
+      }
+    }
+
+    int nextSubaddrIndex = 1;
+
+    while (usedIndexes.contains(nextSubaddrIndex)) {
+      nextSubaddrIndex++;
+    }
+
+    if (_unusedSubaddressIndex != nextSubaddrIndex) {
+      try {
+        final isSupported = await isSubaddressSupported(nextSubaddrIndex);
+        _unusedSubaddressIndex = nextSubaddrIndex;
+        _unusedSubaddressIndexIsSupported = isSupported;
+
+        await SharedPreferencesService.set<int>(
+          SharedPreferencesKeys.unusedSubaddressIndex,
+          _unusedSubaddressIndex!,
+        );
+        await SharedPreferencesService.set<bool>(
+          SharedPreferencesKeys.unusedSubaddressIndexIsSupported,
+          _unusedSubaddressIndexIsSupported!,
+        );
+
+        notifyListeners();
+      } catch (e) {
+        //
+      }
+    }
+  }
+
+  Future<void> loadPersistedUnusedSubaddressIndex() async {
+    _unusedSubaddressIndex =
+        await SharedPreferencesService.get<int>(
+          SharedPreferencesKeys.unusedSubaddressIndex,
+        ) ??
+        1;
+    _unusedSubaddressIndexIsSupported =
+        await SharedPreferencesService.get<bool>(
+          SharedPreferencesKeys.unusedSubaddressIndexIsSupported,
+        ) ??
+        false;
+  }
+
+  Future<bool> isSubaddressSupported(int subaddrIndex) async {
+    final proto = _connectionUseSsl ? 'https' : 'http';
+    final url = Uri.parse('$proto://$_connectionAddress/upsert_subaddrs');
     final primaryAddress = getPrimaryAddress();
     final viewKey = _w2Wallet!.secretViewKey();
     final subaddrs = [
       {
         "key": 0,
         "value": [
-          [0, 1],
+          [0, subaddrIndex],
         ],
       },
     ];
@@ -490,19 +569,14 @@ class WalletModel with ChangeNotifier {
       }
     }
 
-    _serverSupportsSubaddresses = httpStatus == 200;
-
-    await SharedPreferencesService.set<bool>(
-      SharedPreferencesKeys.serverSupportsSubaddresses,
-      _serverSupportsSubaddresses!,
-    );
+    final result = httpStatus == 200;
 
     log(
       LogLevel.info,
-      'Subaddress support check result: $_serverSupportsSubaddresses (status: $httpStatus)',
+      'Subaddress support check result for subaddress $subaddrIndex: $result (status: $httpStatus)',
     );
 
-    notifyListeners();
+    return result;
   }
 
   Future<void> refresh() async {
@@ -786,6 +860,12 @@ class WalletModel with ChangeNotifier {
       SharedPreferencesKeys.serverSupportsSubaddresses,
     );
     await SharedPreferencesService.remove(SharedPreferencesKeys.contacts);
+    await SharedPreferencesService.remove(
+      SharedPreferencesKeys.unusedSubaddressIndex,
+    );
+    await SharedPreferencesService.remove(
+      SharedPreferencesKeys.unusedSubaddressIndexIsSupported,
+    );
   }
 
   Future<bool> hasExistingWallet() async {
@@ -904,37 +984,29 @@ class WalletModel with ChangeNotifier {
     return address;
   }
 
-  Future<String> getUnusedSubaddress() async {
-    final txHistory = await _getFullTxHistory();
-
-    Set<int> usedIndexes = {};
-
-    for (final tx in txHistory) {
-      if (tx.accountIndex == 0) {
-        for (final subaddrIndex in tx.subaddrIndexList) {
-          usedIndexes.add(subaddrIndex);
-        }
-      }
+  String? getUnusedSubaddress() {
+    if (_unusedSubaddressIndex == null) {
+      return null;
     }
 
-    int nextSubaddrIndex = 1;
+    var subaddrIndex = _unusedSubaddressIndex!;
 
-    while (usedIndexes.contains(nextSubaddrIndex)) {
-      nextSubaddrIndex++;
+    if (_unusedSubaddressIndexIsSupported == false) {
+      subaddrIndex -= 1;
     }
 
     log(LogLevel.info, 'Calling Wallet_address with parameters:');
     log(LogLevel.info, '  accountIndex: 0');
-    log(LogLevel.info, '  addressIndex: $nextSubaddrIndex');
+    log(LogLevel.info, '  addressIndex: $subaddrIndex');
 
-    final address = _w2Wallet!.address(
+    final subaddress = _w2Wallet!.address(
       accountIndex: 0,
-      addressIndex: nextSubaddrIndex,
+      addressIndex: subaddrIndex,
     );
 
-    log(LogLevel.info, 'Wallet_address result: $address');
+    log(LogLevel.info, 'Wallet_address result: $subaddress');
 
-    return address;
+    return subaddress;
   }
 
   Future<MoneroPendingTransaction> createTx(
diff --git a/lib/screens/receive.dart b/lib/screens/receive.dart
index ff04e92..ca34dfc 100644
--- a/lib/screens/receive.dart
+++ b/lib/screens/receive.dart
@@ -15,8 +15,6 @@ class ReceiveScreen extends StatefulWidget {
 }
 
 class _ReceiveScreenState extends State<ReceiveScreen> {
-  var _primaryAddress = '';
-  var _subaddress = '';
   var _showSubaddress = true;
   var _previousBrightness = 0.0;
 
@@ -24,7 +22,6 @@ class _ReceiveScreenState extends State<ReceiveScreen> {
   void initState() {
     super.initState();
 
-    _loadAddresses();
     _setBrightnessToMax();
   }
 
@@ -34,18 +31,6 @@ class _ReceiveScreenState extends State<ReceiveScreen> {
     super.dispose();
   }
 
-  Future<void> _loadAddresses() async {
-    final wallet = Provider.of<WalletModel>(context, listen: false);
-
-    final primaryAddress = wallet.getPrimaryAddress();
-    final subaddress = await wallet.getUnusedSubaddress();
-
-    setState(() {
-      _primaryAddress = primaryAddress;
-      _subaddress = subaddress;
-    });
-  }
-
   void _setShowSubaddress(bool value) {
     setState(() {
       _showSubaddress = value;
@@ -69,14 +54,16 @@ class _ReceiveScreenState extends State<ReceiveScreen> {
     final brightness = Theme.of(context).brightness;
     final isDarkTheme = brightness == Brightness.dark;
     final wallet = Provider.of<WalletModel>(context);
-    var address = '';
+    final primaryAddress = wallet.getPrimaryAddress();
+    final subaddress = wallet.getUnusedSubaddress();
+    String? address;
 
     if (wallet.serverSupportsSubaddresses == false) {
-      address = _primaryAddress;
+      address = primaryAddress;
     }
 
     if (wallet.serverSupportsSubaddresses == true) {
-      address = _showSubaddress ? _subaddress : _primaryAddress;
+      address = _showSubaddress ? subaddress : primaryAddress;
     }
 
     return Scaffold(
@@ -84,7 +71,7 @@ class _ReceiveScreenState extends State<ReceiveScreen> {
       body: Center(
         child: Padding(
           padding: EdgeInsets.symmetric(horizontal: 20),
-          child: wallet.serverSupportsSubaddresses == null
+          child: wallet.serverSupportsSubaddresses == null || address == null
               ? CircularProgressIndicator()
               : Column(
                   mainAxisAlignment: MainAxisAlignment.center,
@@ -113,6 +100,13 @@ class _ReceiveScreenState extends State<ReceiveScreen> {
                         textAlign: TextAlign.center,
                         style: TextStyle(color: Colors.red),
                       ),
+                    if (_showSubaddress &&
+                        wallet.unusedSubaddressIndexIsSupported == false)
+                      Text(
+                        i18n.receiveMaxSubaddressesReachedWarn,
+                        textAlign: TextAlign.center,
+                        style: TextStyle(color: Colors.red),
+                      ),
                     GestureDetector(
                       child: Text(
                         address,
@@ -120,7 +114,7 @@ class _ReceiveScreenState extends State<ReceiveScreen> {
                         style: TextStyle(fontFamily: 'monospace'),
                       ),
                       onTap: () async {
-                        await Clipboard.setData(ClipboardData(text: address));
+                        await Clipboard.setData(ClipboardData(text: address!));
                       },
                     ),
                     Row(
diff --git a/lib/services/shared_preferences_service.dart b/lib/services/shared_preferences_service.dart
index 68f950e..1eb2d76 100644
--- a/lib/services/shared_preferences_service.dart
+++ b/lib/services/shared_preferences_service.dart
@@ -17,6 +17,9 @@ class SharedPreferencesKeys {
   static const String txHistoryCount = 'txHistoryCount';
   static const String pendingOutgoingTxs = 'pendingOutgoingTxs';
   static const String contacts = 'contacts';
+  static const String unusedSubaddressIndex = 'unusedSubaddressIndex';
+  static const String unusedSubaddressIndexIsSupported =
+      'unusedSubaddressIndexIsSupported';
 }
 
 class SharedPreferencesService {