/**
 * Relational pipes (library)
 * Copyright © 2019 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/>.
 */

#include "../include/relpipe/common/text/Iconv.h"

namespace relpipe {
namespace common {
namespace text {

class Iconv::IconvInternal {
public:
	static const size_t BUFFER_SIZE_MINIMUM;
	static const size_t BUFFER_SIZE_DEFAULT;
	const size_t bufferSize;
	iconv_t cd;

	IconvInternal(std::string to, std::string from, const size_t bufferSize) : bufferSize(std::max(bufferSize, BUFFER_SIZE_MINIMUM)) {
		cd = iconv_open(to.c_str(), from.c_str());
		if (errno) throw std::string("iconv_open() error: ") + strerror(errno); // TODO: custom exception
	}

	virtual ~IconvInternal() {
		iconv_close(cd);
	}

};

const size_t Iconv::IconvInternal::BUFFER_SIZE_MINIMUM = 2;  // TODO: enough?
const size_t Iconv::IconvInternal::BUFFER_SIZE_DEFAULT = 20;

Iconv::Iconv(std::string to, std::string from) : Iconv(to, from, IconvInternal::BUFFER_SIZE_DEFAULT) {
}

Iconv::Iconv(std::string to, std::string from, size_t bufferSize) {
	internal = new Iconv::IconvInternal(to, from, bufferSize);

}

Iconv::~Iconv() {
	delete internal;
}

std::string Iconv::convert(std::string originalText) {
	std::stringstream result;
	size_t inBytesLeft = originalText.size();
	size_t outBytesLeft = internal->bufferSize;
	char outBuffer[internal->bufferSize];
	char* outBuf = (char*) outBuffer;
	char* inBuf = (char*) originalText.c_str();

	do {
		size_t nconv = iconv(internal->cd, &inBuf, &inBytesLeft, &outBuf, &outBytesLeft);
		if (nconv < 0) throw std::string("iconv() error: ") + strerror(errno); // TODO: custom exception
		// TODO: throw exception if locale is not initialized and platform default "" is used (avoid infinite loop)
		result.write(outBuffer, internal->bufferSize - outBytesLeft);
		outBytesLeft = internal->bufferSize;
		outBuf = (char*) outBuffer;
	} while (inBytesLeft > 0);

	return result.str();
}

}
}
}