/**
 * Relational pipes
 * Copyright © 2019 František Kučera (Frantovo.cz, GlobalCode.info)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 3 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
#pragma once

#include <cstdlib>
#include <iostream>
#include <string>
#include <sstream>
#include <vector>
#include <algorithm>
#include <exception>
#include <regex>

#include <libxml++-2.6/libxml++/libxml++.h>

#include <relpipe/writer/typedefs.h>

#include "Configuration.h"
#include "XMLDocumentConstructor.h"

namespace relpipe {
namespace in {
namespace xmltable {

using namespace relpipe::writer;

class XMLCommand {
private:
	std::wstring_convert<codecvt_utf8<wchar_t>> convertor; // TODO: support also other encodings.

	string_t formatRawXML(string_t rawXML) {
		std::wregex pattern(L"^(<\\?xml version=\"1.0\" encoding=\"UTF-8\"\\?>\\s*)+|\n$");
		// libxml sometimes returns doubled XML declaration (probably a bug), see:
		// --relation ini --records '/' --attribute 'xml' string '.' --mode raw-xml # (but not for --records '//*')
		// so we remove all of them and also trailing line ends (if any).
		return std::regex_replace(rawXML, pattern, L"");
	}

	void importNode(xmlpp::Node* parent, xmlpp::Node* child, AttributeRecipe attributeRecipe) {
		if (dynamic_cast<xmlpp::AttributeNode*> (child)) parent->add_child_with_new_ns(
				convertor.to_bytes(attributeRecipe.rawXmlAttributeWrapper.name),
				convertor.to_bytes(attributeRecipe.rawXmlAttributeWrapper.uri),
				convertor.to_bytes(attributeRecipe.rawXmlAttributeWrapper.prefix))->import_node(child);
		else parent->import_node(child, true);
	}

	void importNode(xmlpp::Document* document, xmlpp::Node* child, AttributeRecipe attributeRecipe) {
		if (dynamic_cast<xmlpp::AttributeNode*> (child)) document->create_root_node(
				convertor.to_bytes(attributeRecipe.rawXmlAttributeWrapper.name),
				convertor.to_bytes(attributeRecipe.rawXmlAttributeWrapper.uri),
				convertor.to_bytes(attributeRecipe.rawXmlAttributeWrapper.prefix))->import_node(child);
		else document->create_root_node_by_import(child, true);
	}

	string_t toRawXML(xmlpp::Node* parent, AttributeRecipe attributeRecipe, xmlpp::Node::PrefixNsMap ns) {
		xmlpp::Document d;
		xmlpp::NodeSet nodes = parent->find(convertor.to_bytes(attributeRecipe.xpath), ns);

		if (attributeRecipe.rawXmlNodeListWrapper.name.size()) {
			d.create_root_node(
					convertor.to_bytes(attributeRecipe.rawXmlNodeListWrapper.name),
					convertor.to_bytes(attributeRecipe.rawXmlNodeListWrapper.uri),
					convertor.to_bytes(attributeRecipe.rawXmlNodeListWrapper.prefix));
			for (xmlpp::Node* node : nodes) importNode(d.get_root_node(), node, attributeRecipe);
		} else {
			if (nodes.size() == 1) importNode(&d, nodes[0], attributeRecipe);
			else if (nodes.size() > 1) throw std::invalid_argument("Multiple nodes found where only one was expected. Use nodelist wrapper."); // TODO: better relpipe exception
			else return L""; // TODO: null
		}
		return formatRawXML(convertor.from_bytes(d.write_to_string()));
	}

public:

	void process(std::istream& input, std::ostream& output, Configuration& configuration) {
		std::shared_ptr<RelationalWriter> writer(Factory::create(output));

		xmlpp::DomParser parser;
		XMLDocumentConstructor documentConstructor(&input, &parser);
		for (ParserOptionRecipe o : configuration.parserOptions) documentConstructor.setOption(convertor.to_bytes(o.uri), convertor.to_bytes(o.value));
		documentConstructor.process();
		if (configuration.xinclude) parser.get_document()->process_xinclude(true);
		xmlpp::Element* root = parser.get_document()->get_root_node();

		xmlpp::Node::PrefixNsMap ns;
		for (int i = 0; i < configuration.namespaceMappings.size(); i++) {
			std::string prefix = convertor.to_bytes(configuration.namespaceMappings[i]);
			std::string uri = convertor.to_bytes(configuration.namespaceMappings[++i]);
			ns[prefix] = uri;
		}

		for (const RelationConfiguration& r : configuration.relationConfigurations) {
			std::vector<relpipe::writer::AttributeMetadata> attributesMetadata;
			for (AttributeRecipe a : r.attributes) attributesMetadata.push_back(AttributeMetadata{a.name, a.type});
			relpipe::writer::string_t name = r.nameIsXPath ? convertor.from_bytes(root->eval_to_string(convertor.to_bytes(r.relation), ns)) : r.relation;
			writer->startRelation(name, attributesMetadata, true);
			for (xmlpp::Node* n : root->find(convertor.to_bytes(r.xpath), ns)) {
				for (AttributeRecipe a : r.attributes) {
					// TODO: convert to bytes only once
					std::string attributeXpath = convertor.to_bytes(a.xpath);
					if (a.mode == Mode::STRING) {
						writer->writeAttribute(convertor.from_bytes(n->eval_to_string(attributeXpath, ns)));
					} else if (a.mode == Mode::BOOLEAN) {
						writer->writeAttribute(n->eval_to_boolean(attributeXpath, ns) ? L"true" : L"false");
					} else if (a.mode == Mode::LINE_NUMBER) {
						xmlpp::NodeSet attributeNodes = n->find(attributeXpath, ns);
						string_t line = attributeNodes.size() ? std::to_wstring(attributeNodes[0]->get_line()) : L""; // TODO: null
						writer->writeAttribute(line);
					} else if (a.mode == Mode::XPATH) {
						xmlpp::NodeSet attributeNodes = n->find(attributeXpath, ns);
						string_t line = attributeNodes.size() ? convertor.from_bytes(attributeNodes[0]->get_path()) : L""; // TODO: null
						writer->writeAttribute(line);
					} else if (a.mode == Mode::RAW_XML) {
						writer->writeAttribute(toRawXML(n, a, ns));
					} else {
						throw logic_error("Unsupported mode."); // should never happer, TODO: better relpipe exception
					}
				}
			}
		}
	}
};

}
}
}