/**

 * Relational pipes

 * 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 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 <string>

#include <vector>

#include <iostream>

#include <sstream>

#include <locale>

#include <codecvt>

#include <regex>

#include <cassert>

#include <relpipe/reader/typedefs.h>

#include <relpipe/reader/TypeId.h>

#include <relpipe/reader/RelpipeReaderException.h>

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

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

namespace relpipe {

namespace out {

namespace recfile {

using namespace relpipe::reader;

class RecfileHandler : public handlers::RelationalReaderStringHandler {

private:

	std::ostream& output;

	wstring_convert<codecvt_utf8<wchar_t>> convertor; // XML output will be always in UTF-8

	std::vector<TypeId> attributeTypes;

	std::vector<string_t> attributeTypeCodes;

	integer_t valueCount = 0;

	integer_t attributeCount = 0;

	integer_t relationCount = 0;

	void writeRelationName(const string_t& name) {

		// FIXME: escaping/filtering

		output << "%rec: " << convertor.to_bytes(name) << std::endl;

	}

	const std::string toRecfileType(const TypeId& type) {

		switch (type) {

			case TypeId::BOOLEAN: return "bool";

			case TypeId::INTEGER: return "int";

			case TypeId::STRING: return "";

			default: throw RelpipeReaderException(L"Unsupported type – unable to convert to a Recfile type");

		}

	}

	}

	void writeSeparator() {

		output << std::endl;

	}

	bool between(wchar_t ch, wchar_t start, wchar_t end) {

		return ch >= start && ch <= end;

	}

	bool isValidNameCharacter(wchar_t ch, bool first) {

		if (first) {

			// also '%' is technically valid here, but it is used for special

			// purposes like the relation name or attribute types

			return /**/between(ch, L'a', L'z')

					|| between(ch, L'A', L'Z');

		} else {

			return ch == L'_'

					|| between(ch, L'a', L'z')

					|| between(ch, L'A', L'Z')

					|| between(ch, L'0', L'9');

		}

	}

		// TODO: multiple escapting mode - including one that is not lossless

		// but allows writing a single '_' inside the name

		for (size_t i = 0, limit = name.size(); i < limit; i++) {

			wchar_t ch = name[i];

			bool valid = isValidNameCharacter(ch, i == 0);

			// Not a lossless round-trip

			// (maybe we could sacrifice some reserved prefix):

		}

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

			output << ch;

			if (ch == '\n') output << "+ ";

		}

		output << std::endl;

	}

	void writeRecordCount() {

		if (attributeCount) {

			output << std::endl << "# Record count: " << (valueCount / attributeCount) << std::endl;

		}

	}

public:

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

	}

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

		writeRecordCount();

		valueCount = 0;

		attributeCount = 0;

		if (relationCount) writeSeparator();

		relationCount++;

		writeRelationName(name);

		attributeCount = attributes.size();

		attributeTypes.resize(attributeCount);

		attributeTypeCodes.resize(attributeCount);

		for (int i = 0; i < attributes.size(); i++) {

			attributeTypes[i] = attributes[i].getTypeId();

			attributeTypeCodes[i] = attributes[i].getTypeName();

		}

	}

	void attribute(const string_t& value) override {

		integer_t i = valueCount % attributeCount;

		if (i == 0) writeSeparator();

		valueCount++;

	}

	void endOfPipe() {

		writeRecordCount();

		if (valueCount) writeSeparator();

	}

};

}

}

}