#include <sstream>

#include <codecvt>

#include <iomanip>

	shared_ptr<relpipe::writer::RelationalWriter> writer;

	std::wstring_convert<codecvt_utf8<wchar_t>> convertor;

	class RelationContext {

	public:

		relpipe::common::type::StringX name;

		std::vector<relpipe::reader::handlers::AttributeMetadata> readerMetadata;

		std::vector<relpipe::writer::AttributeMetadata> writerMetadata;

	} relationContext;

	class RecordContext {

	public:

		std::stringstream buffer;

		shared_ptr<relpipe::writer::RelationalWriter> writer;

		size_t attributeIndex = 0;

	} recordContext;

	relpipe::common::type::StringX toHex(const std::string& octets) {

		std::stringstream hex;

		hex << std::hex << std::setfill('0') << std::hex;

		for (size_t i = 0, size = octets.size(); i < size; i++) hex << std::setw(2) << (0xff & octets[i]);

		return convertor.from_bytes(hex.str());

	}

	SerializeHandler(shared_ptr<relpipe::writer::RelationalWriter> writer, Configuration configuration) : writer(writer), configuration(configuration) {

		// TODO: configurable relation name

		// TODO: configurable attribute name

		// TODO: optional custom attributes with constant value or ordinal number

		// TODO: optional serialization of only certain relations? and certain fields?

		// TODO: optional pass-through of certain relations?

		// TODO: multiple modes? one output record per a) one input record, b) several input records, c) one input relation, … ?

		writer->startRelation(L"message",{

			{L"data", relpipe::writer::TypeId::STRING} // TODO: octet-string (when supported) instead of HEX

		}, true);

		relationContext = RelationContext();

		relationContext.name = name;

		relationContext.readerMetadata = attributes;

		recordContext = RecordContext();

		recordContext.writer.reset(relpipe::writer::Factory::create(recordContext.buffer));

		for (relpipe::reader::handlers::AttributeMetadata readerMetadata : attributes) {

			relationContext.writerMetadata.push_back({readerMetadata.getAttributeName(), writer->toTypeId(readerMetadata.getTypeName())});

		}

		if (recordContext.attributeIndex == 0) {

			recordContext.writer->startRelation(relationContext.name, relationContext.writerMetadata, true);

		}

		recordContext.writer->writeAttribute(value); // TODO: typed values instead of strings

		recordContext.attributeIndex++;

		if (recordContext.attributeIndex % relationContext.readerMetadata.size() == 0) {

			writer->writeAttribute(toHex(recordContext.buffer.str()));

			recordContext = RecordContext();

			recordContext.writer.reset(relpipe::writer::Factory::create(recordContext.buffer));

		}

		// TODO: check number of attribute values