wl_base_help/lib/modes/clash/dns.dart

//fake-ip / redir-host
enum EnhancedMode {
  fakeIp,
  redirHost;

  String get name {
    switch (this) {
      case EnhancedMode.fakeIp:
        return 'fake-ip';
      case EnhancedMode.redirHost:
        return 'redir-host';
      default:
        return '';
    }
  }

  String get value {
    switch (this) {
      case EnhancedMode.fakeIp:
        return 'fake-ip';
      case EnhancedMode.redirHost:
        return 'redir-host';
      default:
        return '';
    }
  }
}

class DNSConfig {
  final bool enable;
  final String listen;
  final bool ipv6;
  final String enhancedMode;
  final List<String> defaultNameserver;
  final List<String> nameserver;
  final List<String> proxyServerNameserver;
  final Map<String,dynamic> nameserverPolicy;
  final String? fakeIpRange;
  final List<String>? fakeIpFilter;
  final List<String>? fallback;
  final FallbackFilter? fallbackFilter;
  DNSConfig({
    required this.enable,
    required this.listen,
    required this.ipv6,
    required this.enhancedMode,
    required this.defaultNameserver,
    required this.nameserver,
    required this.proxyServerNameserver,
    required this.nameserverPolicy,
    this.fakeIpRange,
    this.fakeIpFilter,
    this.fallbackFilter,
    this.fallback
  });

  factory DNSConfig.fromMap(Map<String, dynamic> map) {
    return DNSConfig(
      enable: map['enable'],
      listen: map['listen'],
      ipv6: map['ipv6'],
      enhancedMode: map['enhanced-mode'],
      defaultNameserver: List<String>.from(map['default-nameserver']),
      nameserver: List<String>.from(map['nameserver']),
      proxyServerNameserver: List<String>.from(map['proxy-server-nameserver']),
      nameserverPolicy: Map.from(map['nameserver-policy']).map((key, value) => MapEntry(key, value)),
      fakeIpRange: map['fake-ip-range'],
      fakeIpFilter: map.containsKey('fake-ip-filter') ? List<String>.from(map['fake-ip-filter']) : null,
      fallback: map.containsKey('fallback') ? List<String>.from(map['fallback']) : null,
      fallbackFilter: map.containsKey('fallback-filter') ? FallbackFilter() : null,
    );
  }

  Map<String, dynamic> toJson() {
    return {
      'enable': enable,
      'listen': listen,
      'ipv6': ipv6,
      'enhanced-mode': enhancedMode,
      'default-nameserver': defaultNameserver,
      'nameserver': nameserver,
      'proxy-server-nameserver': proxyServerNameserver,
      'nameserver-policy': nameserverPolicy.map((key, value) => MapEntry(key, value)),
      if (fakeIpRange != null) 'fake-ip-range': fakeIpRange,
      if (fakeIpFilter != null) 'fake-ip-filter': fakeIpFilter,
      if (fallback != null) 'fallback': fallback,
      if (fallbackFilter != null) 'fallback-filter': fallbackFilter,
    };
  }

  String toYaml() {
    var yaml = '''
dns:
  enable: $enable
  listen: $listen
  ipv6: $ipv6
  enhanced-mode: $enhancedMode''';

    if (fakeIpRange != null) {
      yaml += '\n  fake-ip-range: $fakeIpRange';
    }
    if (fakeIpFilter != null && fakeIpFilter!.isNotEmpty) {
      yaml += '\n  fake-ip-filter:';
      for (var filter in fakeIpFilter!) {
        yaml += '\n    - $filter';
      }
    }


   final fallback = this.fallback;
   if(fallback != null){
     yaml += '\n  fallback:\n    - ${fallback.map((ns) => ns).join('\n    - ')}';
   }

    yaml += '\n  default-nameserver:\n    - ${defaultNameserver.map((ns) => ns).join('\n    - ')}';
    yaml += '\n  nameserver:\n    - ${_formatYamlList(nameserver)}';
    yaml += '\n  proxy-server-nameserver:\n    - ${proxyServerNameserver.map((ns) => ns).join('\n    - ')}';
    if (fallbackFilter != null) {
      yaml += '\n${fallbackFilter!.toYaml()}';
    }
    yaml += '\n  nameserver-policy:\n${_mapToYaml(nameserverPolicy)}';

    return yaml;
  }
  String _formatYamlList(List<String> list) {
    return list.map((item) => item.contains('#') ? "'$item'" : item).join('\n    - ');
  }

  String _mapToYaml(Map<String, dynamic> map) {
    var yamlString = '';
    map.forEach((key, value) {
      if (value is String) {
        yamlString += "    '$key': '$value'\n";
      } else if (value is List<String>) {
        var formattedValues = value.map((v) => "'$v'").join(', ');
        yamlString += "    '$key': [$formattedValues]\n";
      }
    });
    return yamlString;
  }

}


class FallbackFilter {
  final bool? geoip;
  final String? geoipCode;
  final List<String>? geosite;
  final List<String>? ipcidr;
  final List<String>? domain;

  FallbackFilter({
    this.geoip,
    this.geoipCode,
    this.geosite,
    this.ipcidr,
    this.domain,
  });

  String toYaml() {
    var yaml = 'fallback-filter:\n';
    if (geoip != null) yaml += '  geoip: $geoip\n';
    if (geoipCode != null) yaml += "  geoip-code: '$geoipCode'\n";
    if (geosite != null && geosite!.isNotEmpty) {
      yaml += '  geosite:\n    - ${geosite!.join('\n    - ')}\n';
    }
    if (ipcidr != null && ipcidr!.isNotEmpty) {
      yaml += '  ipcidr:\n    - ${ipcidr!.join('\n    - ')}\n';
    }
    if (domain != null && domain!.isNotEmpty) {
      yaml += '  domain:\n    - ${domain!.map((d) => "'$d'").join('\n    - ')}\n';
    }
    return yaml;
  }
}