validate method

String? validate(String email)

Validates the email based on user-specified options

Implementation

String? validate(String email) {
  if (email.trim().isEmpty) {
    return 'Email address cannot be empty !';
  }

  // Check minimum length
  if (email.length < options.minLength) {
    return 'Email address must be at least ${options.minLength} characters long !';
  }

  // if (options.checkFormat) {
  //   final emailRegex = RegExp(
  //       r'^(?!.*\.\.)(?!.*\.$)(?!.*\@.*\@)[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$');
  //   if (!emailRegex.hasMatch(email)) {
  //     return 'Please enter a valid email address';
  //   }
  // }

// Separate checks for consecutive dots and trailing dots
  if (options.preventConsecutiveDots && email.contains('..')) {
    return 'Email address cannot contain consecutive dots !';
  }

  if (options.checkEndsWithDot && email.endsWith('.')) {
    return 'Email address cannot end with a dot !';
  }

  // Prevent multiple "@" symbols
  if (options.preventMultipleAtSymbols && email.split('@').length - 1 > 1) {
    return 'Email address cannot contain multiple "@" symbols !';
  }

  // Check for common mistakes
  if (options.checkCommonMistakes) {
    final commonMistakes = {
      '.con': '.com',
      '.cim': '.com',
      '.comm': '.com',
      '@gnail.com': '@gmail.com',
      '@gamil.com': '@gmail.com',
      '@yaho.com': '@yahoo.com',
      '@outlok.com': '@outlook.com',
      '@hotmial.com': '@hotmail.com',
    };

    for (var mistake in commonMistakes.entries) {
      if (email.endsWith(mistake.key)) {
        return 'Did you mean "${email.replaceFirst(mistake.key, mistake.value)}" ?';
      }
    }
  }

  // Prevent disposable email domains
  if (options.preventDisposableEmails) {
    final disposableDomains = [
      'tempmail.com',
      '10minutemail.com',
      'mailinator.com',
      'yopmail.com',
      'guerrillamail.com',
    ];

    final emailDomain = email.split('@').last;
    if (disposableDomains.contains(emailDomain)) {
      return 'Disposable email addresses are not allowed !';
    }
  }
  // Check email format
  if (options.checkFormat) {
    final emailRegex =
        RegExp(r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$');
    if (!emailRegex.hasMatch(email)) {
      return 'Please enter a valid email address !';
    }
  }
  // If all checks pass
  return null;
}