#include "UnionAllHandler.h"

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

	UnionAllHandler unionAllHandler;

	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;

		size_t attributeIndex = 0;

	} recordContext;

	char fromHex(wchar_t ch) {

		if (L'0' <= ch && ch <= L'9') return ch - L'0';

		else if (L'a' <= ch && ch <= L'f') return ch - L'a' + 10;

		else throw relpipe::reader::RelpipeReaderException(L"Unable to decode hexadeximal string.");

	}

	std::stringstream fromHex(const relpipe::common::type::StringX& hex) {

		std::stringstream octets;

		char octet = 0;

		for (size_t i = 0, limit = hex.size(); i < limit; i++) {

			if (i % 2 == 0) {

				octet = fromHex(hex[i]) << 4;

			} else {

				octet += fromHex(hex[i]);

				octets.put(octet);

			}

		}

		return octets;

	}

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

		// TODO: configurable relation name?

		// TODO: configurable attribute name?

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

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

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

		relationContext = RelationContext();

		relationContext.name = name;

		relationContext.readerMetadata = attributes;

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

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

		}

		auto attributeName = relationContext.readerMetadata[recordContext.attributeIndex].getAttributeName();

		if (recordContext.attributeIndex == 0) recordContext = RecordContext();

		if (attributeName == L"data") recordContext.buffer = fromHex(value);

		recordContext.attributeIndex++;

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

			std::stringstream octets = fromHex(value); // TODO: skip this step once we have octet-string data type + typed values instead of strings

			std::shared_ptr<relpipe::reader::RelationalReader> reader(relpipe::reader::Factory::create(octets));

			reader->addHandler(&unionAllHandler);

			reader->process();

			recordContext.attributeIndex = 0;

		}