canUseTouchID.m

- (BOOL)canUseTouchID:(NSError *__autoreleasing *)error {
  BOOL canEvaluate = NO;
  NSError *localError = nil;
  NSError *authError = nil;
  if (!_localAuthContext) {
    _localAuthContext = [[LAContext alloc] init];
  }
  
  if ([_localAuthContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) {
    canEvaluate = YES;
    localError = nil;
  } else {
    if (authError.code == LAErrorPasscodeNotSet) {
      localError = [NSError errorWithDomain:WFTouchIDErrorDomain
                                       code:WFTouchIDPasscodeNotSet
                                   userInfo:authError.userInfo];
    } else if (authError.code == LAErrorTouchIDNotEnrolled) {
      localError = [NSError errorWithDomain:WFTouchIDErrorDomain
                                       code:WFTouchIDTouchIDNotEnrolled
                                   userInfo:authError.userInfo];
    } else {
      localError = [NSError errorWithDomain:WFTouchIDErrorDomain
                                       code:WFTouchIDNotAvailable
                                   userInfo:@{@"info" : @"TouchID not available."}];
    }
  }
  
  BOOL optOutTouchID = ![_userDefaultsManager touchIDChoice];
  if (canEvaluate && optOutTouchID) {
    canEvaluate = NO;
    localError = [NSError errorWithDomain:WFTouchIDErrorDomain
                                     code:WFTouchIDOptOut
                                 userInfo:@{@"info" : @"User opt out of TouchID."}];
  }
  if (canEvaluate == NO) {
    WF_CHECK_ASSIGN_ERROR(error, localError);
  }

  return canEvaluate;
}