/**
 * Relational pipes
 * Copyright © 2020 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 <sstream>

#include "UnescapingINIHandler.h"

using namespace std;
using namespace relpipe::writer;

namespace relpipe {
namespace in {
namespace ini {
namespace lib {

class BasicUnescapingINIContentHandler : public UnescapingINIContentHandler {
protected:

	virtual std::string unescape(const std::string& s) {
		std::stringstream result;
		for (int i = 0, length = s.size(); i < length; i++) {
			char ch = s[i];
			if (i + 1 < length && ch == ESC) {
				ch = s[i + 1];
				if (ch == 'n') put(result, '\n', i);
				else if (ch == 'r') put(result, '\r', i);
				else if (ch == 't') put(result, '\t', i);
				else if (ch == 's') put(result, ' ', i); // TODO: Reconsider what is „basic“ escaping and should be supported.
				else if (ch == '"') put(result, ch, i); //        The delimiters (\n,]",') are already unescaped during the first stage in the INIReader while parsing (the delimiter relevant to given environment is unescaped, e.g. \" in "quoted" value).
				else if (ch == '\'') put(result, ch, i); //       So it does not necessary to do it here. But someone might write a="xxx\'zzz" however it is superfluous because a="xxx'zzz" will also work.
				else if (ch == ']') put(result, ch, i);
				else if (ch == ':') put(result, ch, i);
				else if (ch == ';') put(result, ch, i);
				else if (ch == '#') put(result, ch, i);
				else if (ch == '=') put(result, ch, i);
				else if (ch == ESC && !lastEscaphingPhase) put(result, ESC, i).put(ESC); // copy and skip even the second \ to avoid its misinterpretation in the next cycle
				else if (ch == ESC && lastEscaphingPhase) put(result, ESC, i); // unescape \\ to \.
				else if (lastEscaphingPhase) throw std::logic_error(std::string("Unsupported escape sequence: ") + ch);
				else result.put(ESC); // keep the escape sequence for later unescaping phase
			} else if (ch == ESC) {
				throw std::logic_error(std::string("Missing escape sequence")); // this should not happen
			} else {
				result.put(ch);
			}
		}
		return result.str();
	}

public:

	BasicUnescapingINIContentHandler(INIContentHandler& output, bool lastEscaphingPhase) : UnescapingINIContentHandler(output, lastEscaphingPhase) {
	}

};

}
}
}
}