/**

 * Relational pipes

 * Copyright © 2022 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, version 3 of the License.

 *

 * 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 <regex>

#include <stdexcept>

#include <sstream>

#include <codecvt>

#include <iomanip>

#include <relpipe/common/type/typedefs.h>

#include <relpipe/reader/TypeId.h>

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

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

#include <relpipe/writer/Factory.h>

#include <relpipe/cli/RelpipeCLIException.h>

#include "Configuration.h"

namespace relpipe {

namespace tr {

namespace serialize {

class SerializeHandler : public relpipe::reader::handlers::RelationalReaderValueHandler {

private:

	Configuration configuration;

	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;

public:

	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);

	}

	virtual ~SerializeHandler() = default;

	void startRelation(relpipe::common::type::StringX name, std::vector<relpipe::reader::handlers::AttributeMetadata> attributes) override {

		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())});

		}

	}

	void attribute(const void* value, const std::type_info& type) override {

		if (recordContext.attributeIndex == 0) {

			recordContext = RecordContext();

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

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

		}

		recordContext.writer->writeAttribute(value, type);

		recordContext.attributeIndex++;

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

			recordContext.attributeIndex = 0;

		}

	}

	void endOfPipe() {

		if (recordContext.attributeIndex != 0) throw relpipe::reader::RelpipeReaderException(L"Invalid number of attributes at the end of the pipe – incomplete record.");

	}

};

}

}

}