CW-597-AuthService-Bug (#1346)

* fix: AuthService keychain bug fix

* fix: Fetch read implementation

* fix: Simplify logic for retries

* Minor enhancement

---------

Co-authored-by: Omar Hatem <omarh.ismail1@gmail.com>

lib/core/auth_service.dart

@@ -1,5 +1,7 @@
+import 'dart:async';
 import 'dart:io';
 
+import 'package:cake_wallet/core/secure_storage.dart';
 import 'package:cake_wallet/core/totp_request_details.dart';
 import 'package:cake_wallet/routes.dart';
 import 'package:cake_wallet/src/screens/auth/auth_page.dart';
@@ -64,7 +66,7 @@ class AuthService with Store {
 
   Future<bool> authenticate(String pin) async {
     final key = generateStoreKeyFor(key: SecretStoreKey.pinCodePassword);
-    final encodedPin = await secureStorage.read(key: key);
+    final encodedPin = await readSecureStorage(secureStorage, key);
     final decodedPin = decodedPinCode(pin: encodedPin!);
 
     return decodedPin == pin;
@@ -76,7 +78,8 @@ class AuthService with Store {
   }
 
   Future<bool> requireAuth() async {
-    final timestamp = int.tryParse(await secureStorage.read(key: SecureKey.lastAuthTimeMilliseconds) ?? '0');
+    final timestamp =
+        int.tryParse(await secureStorage.read(key: SecureKey.lastAuthTimeMilliseconds) ?? '0');
     final duration = _durationToRequireAuth(timestamp ?? 0);
     final requiredPinInterval = settingsStore.pinTimeOutDuration;
 

lib/core/key_service.dart

@@ -1,3 +1,4 @@
+import 'package:cake_wallet/core/secure_storage.dart';
 import 'package:flutter_secure_storage/flutter_secure_storage.dart';
 import 'package:cake_wallet/entities/secret_store_key.dart';
 import 'package:cake_wallet/entities/encrypt.dart';
@@ -10,7 +11,7 @@ class KeyService {
   Future<String> getWalletPassword({required String walletName}) async {
     final key = generateStoreKeyFor(
         key: SecretStoreKey.moneroWalletPassword, walletName: walletName);
-    final encodedPassword = await _secureStorage.read(key: key);
+    final encodedPassword = await readSecureStorage(_secureStorage, key);
     return decodeWalletPassword(password: encodedPassword!);
   }
 

lib/core/secure_storage.dart

@@ -0,0 +1,27 @@
+import 'dart:async';
+import 'package:flutter_secure_storage/flutter_secure_storage.dart';
+// For now, we can create a utility function to handle this.
+//
+// However, we could look into abstracting the entire FlutterSecureStorage package
+// so the app doesn't depend on the package directly but an absraction.
+// It'll make these kind of modifications to read/write come from a single point.
+
+Future<String?> readSecureStorage(FlutterSecureStorage secureStorage, String key) async {
+  String? result;
+  const maxWait = Duration(seconds: 3);
+  const checkInterval = Duration(milliseconds: 200);
+
+  DateTime start = DateTime.now();
+
+  while (result == null && DateTime.now().difference(start) < maxWait) {
+    result = await secureStorage.read(key: key);
+
+    if (result != null) {
+      break;
+    }
+
+    await Future.delayed(checkInterval);
+  }
+
+  return result;
+}