/**

 * 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 <memory>

#include <string>

#include <vector>

#include <iostream>

#include <sstream>

#include <locale>

#include <codecvt>

#include <relpipe/reader/typedefs.h>

#include <relpipe/reader/TypeId.h>

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

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

#include "RelpipeCSVWriterException.h"

namespace relpipe {

namespace out {

namespace csv {

using namespace relpipe;

using namespace relpipe::reader;

using namespace relpipe::reader::handlers;

class CSVHandler : public RelationalReaderStringHadler {

private:

	std::ostream& output;

	const char QUOTE = '"';

	std::wstring_convert<std::codecvt_utf8<wchar_t>> convertor; // TODO: local system encoding or generate CSV always in UTF-8 like XML?

	std::vector<AttributeMetadata> firstAttributes;

	integer_t valueCount = 0;

public:

	CSVHandler(std::ostream& output) : output(output) {

	}

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

		if (firstAttributes.empty()) {

			firstAttributes = attributes;

			for (auto attr : attributes) attribute(attr.getAttributeName());

		} else {

			// TODO: UNION ALL if data types and attribute count matches

			throw RelpipeCSVWriterException(L"Only a single relation can be converted to the CSV format.");

		}

	}

	void attribute(const string_t& value) override {

		valueCount++;

		if (value.size() > 0) {

			output << QUOTE;

			for (auto ch : convertor.to_bytes(value)) {

				if (ch == QUOTE) output << QUOTE << QUOTE;

				else output << ch;

			}

			output << QUOTE;

		}

		if (valueCount % firstAttributes.size()) {

			output << ",";

		} else {

			valueCount = 0;

		}

	}

	void endOfPipe() {

		output.flush();

	}

};

}

}

}