Added backups for monero wallet files.

lib/monero/monero_wallet.dart

@@ -3,6 +3,7 @@ import 'package:cake_wallet/entities/transaction_priority.dart';
 import 'package:cake_wallet/monero/monero_amount_format.dart';
 import 'package:cake_wallet/monero/monero_transaction_creation_exception.dart';
 import 'package:cake_wallet/monero/monero_transaction_info.dart';
+import 'package:cake_wallet/monero/monero_wallet_utils.dart';
 import 'package:flutter/foundation.dart';
 import 'package:mobx/mobx.dart';
 import 'package:cw_monero/transaction_history.dart'
@@ -246,6 +247,7 @@ abstract class MoneroWalletBase extends WalletBase<MoneroBalance,
 
     _lastSaveTimestamp = now;
     await monero_wallet.store();
+    await backupWalletFiles(name);
   }
 
   Future<int> getNodeHeight() async => monero_wallet.getNodeHeight();

lib/monero/monero_wallet_service.dart

@@ -1,5 +1,6 @@
 import 'dart:io';
 import 'package:cake_wallet/core/wallet_base.dart';
+import 'package:cake_wallet/monero/monero_wallet_utils.dart';
 import 'package:hive/hive.dart';
 import 'package:cw_monero/wallet_manager.dart' as monero_wallet_manager;
 import 'package:cw_monero/wallet.dart' as monero_wallet;
@@ -55,16 +56,7 @@ class MoneroWalletService extends WalletService<
   MoneroWalletService(this.walletInfoSource);
 
   final Box<WalletInfo> walletInfoSource;
-
-  static Future<void> _removeCache(String name) async {
-    final path = await pathForWallet(name: name, type: WalletType.monero);
-    final cacheFile = File(path);
-
-    if (cacheFile.existsSync()) {
-      cacheFile.deleteSync();
-    }
-  }
-
+  
   static bool walletFilesExist(String path) =>
       !File(path).existsSync() && !File('$path.keys').existsSync();
 
@@ -120,7 +112,7 @@ class MoneroWalletService extends WalletService<
       final isValid = wallet.validate();
 
       if (!isValid) {
-        await _removeCache(name);
+        await restoreOrResetWalletFiles(name);
         wallet.close();
         return openWallet(name, password);
       }
@@ -135,7 +127,7 @@ class MoneroWalletService extends WalletService<
           (e is WalletOpeningException &&
               (e.message == 'std::bad_alloc' ||
                   e.message.contains('bad_alloc')))) {
-        await _removeCache(name);
+        await restoreOrResetWalletFiles(name);
         return openWallet(name, password);
       }
 

lib/monero/monero_wallet_utils.dart

@@ -0,0 +1,88 @@
+import 'dart:io';
+import 'package:cake_wallet/entities/pathForWallet.dart';
+import 'package:cake_wallet/entities/wallet_type.dart';
+
+String backupFileName(String originalPath) {
+  final pathParts = originalPath.split('/');
+  final newName = '#_${pathParts.last}';
+  pathParts.removeLast();
+  pathParts.add(newName);
+  return pathParts.join('/');
+}
+
+Future<void> backupWalletFiles(String name) async {
+  final path = await pathForWallet(name: name, type: WalletType.monero);
+  final cacheFile = File(path);
+  final keysFile = File('$path.keys');
+  final addressListFile = File('$path.address.txt');
+  final newCacheFilePath = backupFileName(cacheFile.path);
+  final newKeysFilePath = backupFileName(keysFile.path);
+  final newAddressListFilePath = backupFileName(addressListFile.path);
+
+  if (cacheFile.existsSync()) {
+    await cacheFile.copy(newCacheFilePath);
+  }
+
+  if (keysFile.existsSync()) {
+    await keysFile.copy(newKeysFilePath);
+  }
+
+  if (addressListFile.existsSync()) {
+    await addressListFile.copy(newAddressListFilePath);
+  }
+}
+
+Future<void> restoreWalletFiles(String name) async {
+  final walletDirPath = await pathForWalletDir(name: name, type: WalletType.monero);
+  final cacheFilePath = '$walletDirPath/$name';
+  final keysFilePath = '$walletDirPath/$name.keys';
+  final addressListFilePath = '$walletDirPath/$name.address.txt';
+  final backupCacheFile = File(backupFileName(cacheFilePath));
+  final backupKeysFile = File(backupFileName(keysFilePath));
+  final backupAddressListFile = File(backupFileName(addressListFilePath));
+
+  if (backupCacheFile.existsSync()) {
+    await backupCacheFile.copy(cacheFilePath);
+  }
+
+  if (backupKeysFile.existsSync()) {
+    await backupKeysFile.copy(keysFilePath);
+  }
+
+  if (backupAddressListFile.existsSync()) {
+    await backupAddressListFile.copy(addressListFilePath);
+  }
+}
+
+Future<bool> backupWalletFilesExists(String name) async {
+  final walletDirPath = await pathForWalletDir(name: name, type: WalletType.monero);
+  final cacheFilePath = '$walletDirPath/$name';
+  final keysFilePath = '$walletDirPath/$name.keys';
+  final addressListFilePath = '$walletDirPath/$name.address.txt';
+  final backupCacheFile = File(backupFileName(cacheFilePath));
+  final backupKeysFile = File(backupFileName(keysFilePath));
+  final backupAddressListFile = File(backupFileName(addressListFilePath));
+
+  return backupCacheFile.existsSync()
+    && backupKeysFile.existsSync()
+    && backupAddressListFile.existsSync();
+}
+
+Future<void> removeCache(String name) async {
+  final path = await pathForWallet(name: name, type: WalletType.monero);
+  final cacheFile = File(path);
+
+  if (cacheFile.existsSync()) {
+    cacheFile.deleteSync();
+  }
+}
+
+Future<void> restoreOrResetWalletFiles(String name) async {
+  final backupsExists = await backupWalletFilesExists(name);
+
+  if (backupsExists) {
+    await restoreWalletFiles(name);
+  }
+
+  removeCache(name);
+}