/**
 * 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;

	}

};

}
}
}