/**

 * 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 <string>

#include <vector>

#include <iostream>

#include <sstream>

#include <locale>

#include <codecvt>

#include <regex>

#include <relpipe/reader/typedefs.h>

#include <relpipe/reader/TypeId.h>

#include <relpipe/reader/handlers/RelationalReaderStringHandler.h>

#include <relpipe/reader/handlers/AttributeMetadata.h>

namespace relpipe {

namespace out {

namespace xml {

using namespace relpipe::reader;

class XmlHandler : public handlers::RelationalReaderStringHadler {

private:

	std::wstring_convert<std::codecvt_utf8<wchar_t>> convertor; // XML output will be always in UTF-8

	const char* INDENT = "\t";

	std::ostream &output;

	std::vector<TypeId> columnTypes;

	std::vector<string_t> columnTypeCodes;

	std::vector<string_t> columnNames;

	integer_t valueCount = 0;

	integer_t columnCount = 0;

	integer_t relationCount = 0;

	const std::string escapeXmlText(const string_t &value) {

		// TODO: really bad performance → rewrite

		// 72 % of whole relpipe-out-xml according to valgrind/callgrind

		std::wstringstream result;

		for (auto & ch : value) {

			switch (ch) {

				case L'&': result << L"&amp;";

					break;

				case L'<': result << L"&lt;";

					break;

				case L'>': result << L"&gt;";

					break;

				case L'\'': result << L"&apos;"; // TODO: escape ' and " only in attributes

					break;

				case L'"': result << L"&quot;"; // TODO: escape ' and " only in attributes

					break;

				default: result << ch;

			}

		}

		return convertor.to_bytes(result.str());

	}

public:

	XmlHandler(std::ostream& output) : output(output) {

	}

	void startRelation(string_t name, std::vector<handlers::AttributeMetadata> attributes) override {

		// TODO: refactor and move common XML functions to relpipe-lib-xml

		valueCount = 0;

		columnCount = 0;

		if (relationCount == 0) {

			output << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" << std::endl;

			output << "<pipe>" << std::endl;

			// TODO: xmlns

		} else {

			output << INDENT << INDENT << "</record>" << std::endl;

			output << INDENT << "</relation>" << std::endl;

		}

		relationCount++;

		output << INDENT << "<relation>" << std::endl;

		output << INDENT << INDENT << "<name>" << escapeXmlText(name) << "</name>" << std::endl;

		columnCount = attributes.size();

		columnTypes.resize(columnCount);

		columnTypeCodes.resize(columnCount);

		columnNames.resize(columnCount);

		for (int i = 0; i < attributes.size(); i++) {

			columnNames[i] = attributes[i].getAttributeName();

			columnTypes[i] = attributes[i].getTypeId();

			columnTypeCodes[i] = attributes[i].getTypeName();

		}

		// TODO: print attribute metadata

	}

	void attribute(const string_t& value) override {

		integer_t i = valueCount % columnCount;

		if (i == 0 && valueCount) output << INDENT << INDENT << "</record>" << std::endl;

		if (i == 0) output << INDENT << INDENT << "<record>" << std::endl;

		valueCount++;

		// TODO: print attribute metadata (optional)

		output << INDENT << INDENT << INDENT << "<attribute>";

		output << escapeXmlText(value);

		output << "</attribute>" << std::endl;

	}

	void endOfPipe() {

		if (valueCount) output << INDENT << INDENT << "</record>" << std::endl;

		if (relationCount) output << INDENT << "</relation>" << std::endl;

		output << "</pipe>" << std::endl;

	}

};

}

}

}