#include <sstream>

#include <stdexcept>

#include <gumbo.h>

	std::string readInput() {

		std::string result(std::istreambuf_iterator<char>(*input),{});

		return result;

	}

	class GumboTree {

	private:

		std::string htmlText;

		GumboOptions options = kGumboDefaultOptions;

		GumboOutput* tree = nullptr;

		void html2xml(xmlpp::Document* document, xmlpp::Element* parent, GumboNode* htmlNode) {

			if (htmlNode->type == GUMBO_NODE_ELEMENT || htmlNode->type == GUMBO_NODE_TEMPLATE) {

				std::string elementName = gumbo_normalized_tagname(htmlNode->v.element.tag);

				if (htmlNode->v.element.tag == GUMBO_TAG_UNKNOWN || elementName.empty()) {

					elementName = "UNKNOWN";

					// TODO: find original element name, maybe gumbo_normalize_svg_tagname()

				}

				// TODO: optional support for namespaces

				xmlpp::Element* element;

				if (parent == nullptr) {

					element = document->create_root_node(elementName);

				} else {

					element = parent->add_child(elementName);

				}

				for (size_t i = 0; i < htmlNode->v.element.attributes.length; i++) {

					GumboAttribute* htmlAttribute = static_cast<GumboAttribute*> (htmlNode->v.element.attributes.data[i]);

					element->set_attribute(htmlAttribute->name, htmlAttribute->value);

				}

				for (size_t i = 0; i < htmlNode->v.element.children.length; i++) {

					html2xml(document, element, static_cast<GumboNode*> (htmlNode->v.element.children.data[i]));

				}

			} else if (htmlNode->type == GUMBO_NODE_TEXT || htmlNode->type == GUMBO_NODE_WHITESPACE) {

				std::string value = htmlNode->v.text.text;

				parent->add_child_text(value);

			} else if (htmlNode->type == GUMBO_NODE_CDATA) {

				parent->add_child_cdata(htmlNode->v.text.text);

			} else if (htmlNode->type == GUMBO_NODE_COMMENT) {

				parent->add_child_comment(htmlNode->v.text.text);

			} else {

				throw std::logic_error("Unable to convert HTML to XML: Unsupported GumboNode type: " + std::to_string(htmlNode->type));

			}

		}

	public:

		GumboTree(std::string htmlText) : htmlText(htmlText) {

			tree = gumbo_parse_with_options(&options, this->htmlText.c_str(), this->htmlText.size());

			if (tree == nullptr) throw std::logic_error("Unable to parse HTML text.");

		}

		virtual ~GumboTree() {

			if (tree) gumbo_destroy_output(&options, tree);

		}

		void exportTo(xmlpp::Document* document) {

			auto doctype = tree->document->v.document;

			if (strlen(doctype.name)) document->set_internal_subset(doctype.name, doctype.public_identifier, doctype.system_identifier);

			html2xml(document, nullptr, tree->root);

		}

	};

		GumboTree gumboTree(readInput());

		gumboTree.exportTo(parser->get_document());