validate method

@override String? validate(BuildContext context, String fieldName, String? value)

Function to validate the form input. It takes a string and returns an String error message if the input is invalid or null if the input is valid.

Implementation

@override
String? validate(
  BuildContext context,
  String fieldName,
  String? value,
) {
  _isValid = true;
  _longErrorMessage = null;
  _shortErrorMessage = null;

  if (value != null && value.isNotEmpty) {
    final l10n = context.l10n;

    if (value.length < 8) {
      _shortErrorMessage = l10n.tooShortMessage;
      _longErrorMessage = l10n.passwordTooShortErrorMessage;
      return _shortErrorMessage;
    }
    final p1 = RegExp(
        r'^(?=.*[-_=+()!@#$%^&*{}<>|";:,./?\(\)\[\]\\])[-_=+()!@#$%^&*{}<>|";:,./?\(\)\[\]\\a-zA-Z0-9]{8,}$');
    _isValid = p1.hasMatch(value);
    if (!_isValid) {
      _shortErrorMessage = l10n.invalidMessage;
      _longErrorMessage = l10n.passwordSpecialCharErrorMessage;
      return _shortErrorMessage;
    }
    final p2 = RegExp(
        r'^(?=.*[a-z])[-_=+()!@#$%^&*{}<>|";:,./?\(\)\[\]\\a-zA-Z0-9]{8,}$');
    _isValid = p2.hasMatch(value);
    if (!_isValid) {
      _shortErrorMessage = l10n.invalidMessage;
      _longErrorMessage = l10n.passwordLowercaseCharErrorMessage;
      return _shortErrorMessage;
    }
    final p3 = RegExp(
        r'^(?=.*[A-Z])[-_=+()!@#$%^&*{}<>|";:,./?\(\)\[\]\\a-zA-Z0-9]{8,}$');
    _isValid = p3.hasMatch(value);
    if (!_isValid) {
      _shortErrorMessage = l10n.invalidMessage;
      _longErrorMessage = l10n.passwordUppercaseCharErrorMessage;
      return _shortErrorMessage;
    }
    final p4 = RegExp(
        r'^(?=.*[0-9])[-_=+()!@#$%^&*{}<>|";:,./?\(\)\[\]\\a-zA-Z0-9]{8,}$');
    _isValid = p4.hasMatch(value);
    if (!_isValid) {
      _shortErrorMessage = l10n.invalidMessage;
      _longErrorMessage = l10n.passwordNumberErrorMessage;
      return _shortErrorMessage;
    }
  }
  return null;
}