/**

 * Relational pipes (library)

 * 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 Lesser General Public License as published by the Free Software Foundation;

 *    version 3 of the License or (at your option)

 *  - GNU General Public License as published by the Free Software Foundation;

 *    version 2 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 <string>

#include <cstring>

#include <iostream>

#include <vector>

#include <stdexcept>

#include <relpipe/protocol/constants.h>

#include "../include/relpipe/writer/typedefs.h"

#include "../include/relpipe/writer/RelationalWriter.h"

#include "../include/relpipe/writer/TypeId.h"

#include "../include/relpipe/writer/AttributeMetadata.h"

#include "DataTypeWriterBase.h"

#include "types/BooleanDataTypeWriter.h"

#include "types/IntegerDataTypeWriter.h"

#include "types/StringDataTypeWriter.h"

namespace relpipe {

namespace writer {

using namespace relpipe::protocol;

class StreamRelationalWriter : public RelationalWriter {

private:

	std::ostream &output;

	types::BooleanDataTypeWriter booleanWriter;

	types::IntegerDataTypeWriter integerWriter;

	types::StringDataTypeWriter stringWriter;

	std::vector<DataTypeWriterBase*> writers = {&booleanWriter, &integerWriter, &stringWriter};

	/**

	 * count of columns in the current table

	 */

	integer_t columnCount;

	/**

	 * number of column (0 = first) that will be written; after writing, the number is increased and prepared for next one

	 */

	integer_t currentColumn;

	/**

	 * types of columns in the current table

	 */

	std::vector<TypeId> columnTypes;

	void writeString(const string_t &stringValue, const TypeId typeId) {

		// TODO: cache writers at given positions

		for (DataTypeWriterBase* writer : writers) if (writer->supports(typeId)) return writer->writeString(output, stringValue);

		throw RelpipeWriterException(L"Unsupported data type: " + static_cast<integer_t> (typeId));

	}

	void writeRaw(const void* value, const type_info& typeInfo, const TypeId typeId) {

		// TODO: cache writers at given positions

		for (DataTypeWriterBase* writer : writers) if (writer->supports(typeId)) return writer->writeRaw(output, value, typeInfo);

		throw RelpipeWriterException(L"Unsupported data type: " + static_cast<integer_t> (typeId));

	}

	BufferingMode decodeBufferingMode(std::string modeName) {

		if (modeName == "AUTO") return BufferingMode::AUTO;

		else if (modeName == "ENVIRONMENT") return BufferingMode::ENVIRONMENT;

		else if (modeName == "RELATION") return BufferingMode::RELATION;

		else if (modeName == "RECORD") return BufferingMode::RECORD;

		else if (modeName == "ATTRIBUTE") return BufferingMode::ATTRIBUTE;

		else throw std::invalid_argument("Invalid value of BufferingMode.");

	}

	void updateBufferingMode() {

		if (bufferingMode == BufferingMode::ENVIRONMENT) {

			bufferingMode = bufferingModeEnvDefault;

			try {

				char* modeName = getenv("RELPIPE_WRITER_BUFFERING_MODE");

				if (modeName && strlen(modeName)) bufferingMode = decodeBufferingMode(modeName);

			} catch (...) {

				throw RelpipeWriterException(L"Invalid value of the RELPIPE_WRITER_BUFFERING_MODE environmental variable.");

			}

			if (bufferingMode == BufferingMode::ENVIRONMENT) throw RelpipeWriterException(L"RELPIPE_WRITER_BUFFERING_MODE must not be set to ENVIRONMENT (infinite recursion)");

		}

	}

public:

	StreamRelationalWriter(std::ostream &output) :

	output(output) {

	}

	TypeId toTypeId(const string_t typeCode) override {

		for (DataTypeWriterBase* writer : writers) if (writer->supports(typeCode)) return writer->getTypeId();

		throw RelpipeWriterException(L"Unsupported data type: " + typeCode);

	}

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

		string_t tableName = name;

		columnCount = attributes.size();

		currentColumn = 0;

		// Write table name and column count:

		if (writeHeader) {

			integerWriter.writeValue(output, DATA_PART_START);

			stringWriter.writeValue(output, tableName);

			integerWriter.writeValue(output, columnCount);

		}

		columnTypes.clear();

		columnTypes.resize(columnCount);

		// Write column names:

		if (writeHeader) {

			for (size_t c = 0; c < columnCount; c++) {

				wstring columnName = attributes[c].attributeName;

				stringWriter.writeValue(output, columnName);

			}

		}

		// Write column types:

		for (size_t c = 0; c < columnCount; c++) {

			TypeId typeId = attributes[c].typeId;

			if (writeHeader) integerWriter.writeValue(output, static_cast<integer_t> (typeId));

			columnTypes[c] = typeId;

		}

		if (bufferingMode >= BufferingMode::RELATION && bufferingMode <= BufferingMode::ATTRIBUTE) output.flush();

	}

	void writeAttribute(const string_t& value) override {

		if (currentColumn == 0) integerWriter.writeValue(output, DATA_PART_ROW);

		// TODO: select writer for each attribute just once in startRelation() instead of looking it each time here

		writeString(value, columnTypes[currentColumn]);

		bool endOfRedord = ++currentColumn == columnCount;

		if (endOfRedord) currentColumn = 0;

		if (bufferingMode == BufferingMode::ATTRIBUTE || (endOfRedord && bufferingMode == BufferingMode::RECORD)) output.flush();

	}

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

		if (currentColumn == 0) integerWriter.writeValue(output, DATA_PART_ROW);

		// TODO: select writer for each attribute just once in startRelation() instead of looking it each time here

		writeRaw(value, type, columnTypes[currentColumn]);

		bool endOfRedord = ++currentColumn == columnCount;

		if (endOfRedord) currentColumn = 0;

		if (bufferingMode == BufferingMode::ATTRIBUTE || (endOfRedord && bufferingMode == BufferingMode::RECORD)) output.flush();

	}

	void setBufferingMode(BufferingMode mode, BufferingMode envDefault) override {

		bufferingMode = mode;

		bufferingModeEnvDefault = envDefault;

	}

};

}

}