private void SerializeNode()

in src/Elastic.Apm/Libraries/Newtonsoft.Json/Converters/XmlNodeConverter.cs [1297:1459]
145 lines of code
41 McCabe index (conditional complexity)

        private void SerializeNode(JsonWriter writer, IXmlNode node, XmlNamespaceManager manager, bool writePropertyName)
        {
            switch (node.NodeType)
            {
                case XmlNodeType.Document:
                case XmlNodeType.DocumentFragment:
                    SerializeGroupedNodes(writer, node, manager, writePropertyName);
                    break;
                case XmlNodeType.Element:
                    if (IsArray(node) && AllSameName(node) && node.ChildNodes.Count > 0)
                    {
                        SerializeGroupedNodes(writer, node, manager, false);
                    }
                    else
                    {
                        manager.PushScope();

                        foreach (IXmlNode attribute in node.Attributes)
                        {
                            if (attribute.NamespaceUri == "http://www.w3.org/2000/xmlns/")
                            {
                                string namespacePrefix = (attribute.LocalName != "xmlns")
                                    ? XmlConvert.DecodeName(attribute.LocalName)
                                    : string.Empty;
                                string? namespaceUri = attribute.Value;
                                if (namespaceUri == null)
                                {
                                    throw new JsonSerializationException("Namespace attribute must have a value.");
                                }

                                manager.AddNamespace(namespacePrefix, namespaceUri);
                            }
                        }

                        if (writePropertyName)
                        {
                            writer.WritePropertyName(GetPropertyName(node, manager));
                        }

                        if (!ValueAttributes(node.Attributes) && node.ChildNodes.Count == 1
                            && node.ChildNodes[0].NodeType == XmlNodeType.Text)
                        {
                            // write elements with a single text child as a name value pair
                            writer.WriteValue(node.ChildNodes[0].Value);
                        }
                        else if (node.ChildNodes.Count == 0 && node.Attributes.Count == 0)
                        {
                            IXmlElement element = (IXmlElement)node;

                            // empty element
                            if (element.IsEmpty)
                            {
                                writer.WriteNull();
                            }
                            else
                            {
                                writer.WriteValue(string.Empty);
                            }
                        }
                        else
                        {
                            writer.WriteStartObject();

                            for (int i = 0; i < node.Attributes.Count; i++)
                            {
                                SerializeNode(writer, node.Attributes[i], manager, true);
                            }

                            SerializeGroupedNodes(writer, node, manager, true);

                            writer.WriteEndObject();
                        }

                        manager.PopScope();
                    }

                    break;
                case XmlNodeType.Comment:
                    if (writePropertyName)
                    {
                        writer.WriteComment(node.Value);
                    }
                    break;
                case XmlNodeType.Attribute:
                case XmlNodeType.Text:
                case XmlNodeType.CDATA:
                case XmlNodeType.ProcessingInstruction:
                case XmlNodeType.Whitespace:
                case XmlNodeType.SignificantWhitespace:
                    if (node.NamespaceUri == "http://www.w3.org/2000/xmlns/" && node.Value == JsonNamespaceUri)
                    {
                        return;
                    }

                    if (node.NamespaceUri == JsonNamespaceUri)
                    {
                        if (node.LocalName == "Array")
                        {
                            return;
                        }
                    }

                    if (writePropertyName)
                    {
                        writer.WritePropertyName(GetPropertyName(node, manager));
                    }
                    writer.WriteValue(node.Value);
                    break;
                case XmlNodeType.XmlDeclaration:
                    IXmlDeclaration declaration = (IXmlDeclaration)node;
                    writer.WritePropertyName(GetPropertyName(node, manager));
                    writer.WriteStartObject();

                    if (!StringUtils.IsNullOrEmpty(declaration.Version))
                    {
                        writer.WritePropertyName("@version");
                        writer.WriteValue(declaration.Version);
                    }
                    if (!StringUtils.IsNullOrEmpty(declaration.Encoding))
                    {
                        writer.WritePropertyName("@encoding");
                        writer.WriteValue(declaration.Encoding);
                    }
                    if (!StringUtils.IsNullOrEmpty(declaration.Standalone))
                    {
                        writer.WritePropertyName("@standalone");
                        writer.WriteValue(declaration.Standalone);
                    }

                    writer.WriteEndObject();
                    break;
                case XmlNodeType.DocumentType:
                    IXmlDocumentType documentType = (IXmlDocumentType)node;
                    writer.WritePropertyName(GetPropertyName(node, manager));
                    writer.WriteStartObject();

                    if (!StringUtils.IsNullOrEmpty(documentType.Name))
                    {
                        writer.WritePropertyName("@name");
                        writer.WriteValue(documentType.Name);
                    }
                    if (!StringUtils.IsNullOrEmpty(documentType.Public))
                    {
                        writer.WritePropertyName("@public");
                        writer.WriteValue(documentType.Public);
                    }
                    if (!StringUtils.IsNullOrEmpty(documentType.System))
                    {
                        writer.WritePropertyName("@system");
                        writer.WriteValue(documentType.System);
                    }
                    if (!StringUtils.IsNullOrEmpty(documentType.InternalSubset))
                    {
                        writer.WritePropertyName("@internalSubset");
                        writer.WriteValue(documentType.InternalSubset);
                    }

                    writer.WriteEndObject();
                    break;
                default:
                    throw new JsonSerializationException("Unexpected XmlNodeType when serializing nodes: " + node.NodeType);
            }
        }