/**
 * Relational pipes
 * Copyright © 2018 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, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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 <vector>
#include <algorithm>

#include <xercesc/sax2/SAX2XMLReader.hpp>
#include <xercesc/sax2/XMLReaderFactory.hpp>
#include <xercesc/sax2/DefaultHandler.hpp>
#include <xercesc/sax2/Attributes.hpp>
#include <xercesc/util/XMLString.hpp>

#include <relpipe/writer/typedefs.h>

#include "StreamInputSource.h"
#include "XercesStringConvertor.h"

namespace relpipe {
namespace in {
namespace xml {

using namespace relpipe::writer;
using namespace xercesc;

class XMLCommand {
private:

	class RelpipeSaxHandler : public xercesc::DefaultHandler {
	private:
		unique_ptr<RelationalWriter> writer;
		XercesStringConvertor xConvertor;

	public:

		RelpipeSaxHandler(std::ostream& output) : DefaultHandler(), writer(Factory::create(output)) {
		}

		void startDocument() override {
			//XMLString::
			// TODO: remove demo
			writer->startRelation(L"xml",{
				{L"event", TypeId::STRING},
				{L"uri", TypeId::STRING},
				{L"localname", TypeId::STRING},
				{L"qname", TypeId::STRING},
				{L"chars", TypeId::STRING}
			}, true);
		}

		void startElement(const XMLCh * const uri, const XMLCh * const localname, const XMLCh * const qname, const Attributes& attrs) override {
			writer->writeAttribute(L"startElement");
			writer->writeAttribute(xConvertor.toString(uri));
			writer->writeAttribute(xConvertor.toString(localname));
			writer->writeAttribute(xConvertor.toString(qname));
			writer->writeAttribute(L"");

			for (int i = 0; i < attrs.getLength(); i++) {
				writer->writeAttribute(L"attribute");
				writer->writeAttribute(xConvertor.toString(attrs.getURI(i)));
				writer->writeAttribute(xConvertor.toString(attrs.getLocalName(i)));
				writer->writeAttribute(xConvertor.toString(attrs.getQName(i)));
				writer->writeAttribute(xConvertor.toString(attrs.getValue(i)));
			}
		}

		void endElement(const XMLCh * const uri, const XMLCh * const localname, const XMLCh * const qname) override {
			writer->writeAttribute(L"endElement");
			writer->writeAttribute(xConvertor.toString(uri));
			writer->writeAttribute(xConvertor.toString(localname));
			writer->writeAttribute(xConvertor.toString(qname));
			writer->writeAttribute(L"");
		}

		void characters(const XMLCh * const chars, const XMLSize_t length) override {
			writer->writeAttribute(L"characters");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
			writer->writeAttribute(xConvertor.toString(chars));
		}

		void comment(const XMLCh * const chars, const XMLSize_t length) override {
			writer->writeAttribute(L"comment");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
			writer->writeAttribute(xConvertor.toString(chars));
		}

		void startCDATA() override {
			writer->writeAttribute(L"startCDATA");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
		}

		void endCDATA() override {
			writer->writeAttribute(L"endCDATA");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
		}

		void endDocument() override {
			writer->writeAttribute(L"endDocument");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
			writer->writeAttribute(L"");
		}

	};

public:

	void process(std::istream& input, std::ostream& output) {
		XMLPlatformUtils::Initialize();
		unique_ptr<SAX2XMLReader> parser(XMLReaderFactory::createXMLReader());
		parser->setFeature(XMLUni::fgSAX2CoreValidation, true);
		parser->setFeature(XMLUni::fgSAX2CoreNameSpaces, true);
		// TODO: optional unbuffered mode for more fluent output?
		// http://xerces.apache.org/xerces-c/program-sax2-3.html#SAX2Features
		// parser->setProperty(XMLUni::fgXercesLowWaterMark, ...);
		// parser->setInputBufferSize(...);

		RelpipeSaxHandler saxHandler(output);
		parser->setContentHandler(&saxHandler);
		parser->setLexicalHandler(&saxHandler); // TODO: remove – needed only for comments
		parser->setErrorHandler(&saxHandler);

		StreamInputSource inputSource(input);

		parser->parse(inputSource);
	}
};

}
}
}