| 1 | import 'dart:async'; |
| 2 | import 'package:flutter/material.dart'; |
| 3 | import 'package:shared_preferences/shared_preferences.dart'; |
| 4 | import 'package:mobx/mobx.dart'; |
| 5 | import 'package:cake_wallet/view_model/auth_state.dart'; |
| 6 | import 'package:cake_wallet/core/auth_service.dart'; |
| 7 | import 'package:cake_wallet/generated/i18n.dart'; |
| 8 | import 'package:cake_wallet/core/execution_state.dart'; |
| 9 | import 'package:cake_wallet/entities/biometric_auth.dart'; |
| 10 | import 'package:cake_wallet/store/settings_store.dart'; |
| 11 | |
| 12 | part 'auth_view_model.g.dart'; |
| 13 | |
| 14 | class AuthViewModel = AuthViewModelBase with _$AuthViewModel; |
| 15 | |
| 16 | abstract class AuthViewModelBase with Store { |
| 17 | AuthViewModelBase( |
| 18 | this._authService, this._sharedPreferences, this._settingsStore, this._biometricAuth) |
| 19 | : _failureCounter = 0, |
| 20 | state = InitialExecutionState() { |
| 21 | reaction((_) => state, _saveLastAuthTime); |
| 22 | } |
| 23 | |
| 24 | static const maxFailedLogins = 3; |
| 25 | static const banTimeout = 180; // 3 minutes |
| 26 | final banTimeoutKey = S.current.auth_store_ban_timeout; |
| 27 | |
| 28 | @observable |
| 29 | ExecutionState state; |
| 30 | |
| 31 | int get pinLength => _settingsStore.pinCodeLength; |
| 32 | |
| 33 | bool get isBiometricalAuthenticationAllowed => _settingsStore.allowBiometricalAuthentication; |
| 34 | |
| 35 | @observable |
| 36 | int _failureCounter; |
| 37 | |
| 38 | final AuthService _authService; |
| 39 | final BiometricAuth _biometricAuth; |
| 40 | final SharedPreferences _sharedPreferences; |
| 41 | final SettingsStore _settingsStore; |
| 42 | |
| 43 | @action |
| 44 | Future<void> auth({required String password}) async { |
| 45 | state = InitialExecutionState(); |
| 46 | final _banDuration = banDuration(); |
| 47 | |
| 48 | if (_banDuration != null) { |
| 49 | state = AuthenticationBanned( |
| 50 | error: S.current.auth_store_banned_for + |
| 51 | '${_banDuration.inMinutes}' + |
| 52 | S.current.auth_store_banned_minutes); |
| 53 | return; |
| 54 | } |
| 55 | |
| 56 | state = IsExecutingState(); |
| 57 | final isSuccessfulAuthenticated = await _authService.authenticate(password); |
| 58 | |
| 59 | if (isSuccessfulAuthenticated) { |
| 60 | WidgetsBinding.instance.addPostFrameCallback((timeStamp) { |
| 61 | state = ExecutedSuccessfullyState(); |
| 62 | _failureCounter = 0; |
| 63 | }); |
| 64 | } else { |
| 65 | _failureCounter += 1; |
| 66 | |
| 67 | if (_failureCounter >= maxFailedLogins) { |
| 68 | final banDuration = await ban(); |
| 69 | state = AuthenticationBanned( |
| 70 | error: S.current.auth_store_banned_for + |
| 71 | '${banDuration.inMinutes}' + |
| 72 | S.current.auth_store_banned_minutes); |
| 73 | return; |
| 74 | } |
| 75 | |
| 76 | state = FailureState(S.current.auth_store_incorrect_password); |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | Duration? banDuration() { |
| 81 | final unbanTimestamp = _sharedPreferences.getInt(banTimeoutKey); |
| 82 | |
| 83 | if (unbanTimestamp == null) { |
| 84 | return null; |
| 85 | } |
| 86 | |
| 87 | final unbanTime = DateTime.fromMillisecondsSinceEpoch(unbanTimestamp); |
| 88 | final now = DateTime.now(); |
| 89 | |
| 90 | if (now.isAfter(unbanTime)) { |
| 91 | return null; |
| 92 | } |
| 93 | |
| 94 | return Duration(milliseconds: unbanTimestamp - now.millisecondsSinceEpoch); |
| 95 | } |
| 96 | |
| 97 | Future<Duration> ban() async { |
| 98 | final multiplier = _failureCounter - maxFailedLogins + 1; |
| 99 | final timeout = (multiplier * banTimeout) * 1000; |
| 100 | final unbanTimestamp = DateTime.now().millisecondsSinceEpoch + timeout; |
| 101 | await _sharedPreferences.setInt(banTimeoutKey, unbanTimestamp); |
| 102 | |
| 103 | return Duration(milliseconds: timeout); |
| 104 | } |
| 105 | |
| 106 | @action |
| 107 | Future<void> biometricAuth() async { |
| 108 | try { |
| 109 | if (await _biometricAuth.canCheckBiometrics() && await _biometricAuth.isAuthenticated()) { |
| 110 | state = ExecutedSuccessfullyState(); |
| 111 | } else { |
| 112 | throw Exception('Biometric authentication failed'); |
| 113 | } |
| 114 | } catch (e) { |
| 115 | state = FailureState(e.toString()); |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | void _saveLastAuthTime(ExecutionState state) { |
| 120 | if (state is ExecutedSuccessfullyState) { |
| 121 | _authService.saveLastAuthTime(); |
| 122 | } |
| 123 | } |
| 124 | } |