/**

 * 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

 *

 * 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 <regex>

#include <relpipe/reader/typedefs.h>

#include <relpipe/reader/TypeId.h>

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

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

#include <relpipe/writer/Factory.h>

#include <relpipe/cli/RelpipeCLIException.h>

namespace relpipe {

namespace tr {

namespace grep {

using namespace std;

using namespace relpipe;

using namespace relpipe::reader;

using namespace relpipe::reader::handlers;

class CutHandler : public RelationalReaderStringHandler {

private:

	shared_ptr<writer::RelationalWriter> relationalWriter;

	wregex relationNameRegEx;

	vector<wregex> attributeNameRegExes;

	vector<integer_t> currentAttributeMapping;

	vector<string_t> currentRecord;

	integer_t currentAttributeIndex = 0;

	boolean_t filterCurrentRelation = false;

public:

	CutHandler(ostream& output, const vector<string_t>& arguments) {

		relationalWriter.reset(writer::Factory::create(output));

		if (arguments.size() >= 2) {

			relationNameRegEx = wregex(arguments[0]);

			for (int i = 1; i < arguments.size(); i++) attributeNameRegExes.push_back(wregex(arguments[i]));

		} else {

			throw cli::RelpipeCLIException(L"Usage: relpipe-tr-cut <relationNameRegExp> <attributeNameRegExp> [<otherAttributeNameRegExp> ...]", cli::CLI::EXIT_CODE_UNKNOWN_COMMAND);

		}

	}

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

		currentRecord.resize(attributes.size());

		// TODO: move to a reusable method (or use same metadata on both reader and writer side?)

		vector<writer::AttributeMetadata> allWriterMetadata;

		for (AttributeMetadata readerMetadata : attributes) {

			allWriterMetadata.push_back({readerMetadata.getAttributeName(), relationalWriter->toTypeId(readerMetadata.getTypeName())});

		}

		vector<writer::AttributeMetadata> writerMetadata;

		filterCurrentRelation = regex_match(name, relationNameRegEx);

		if (filterCurrentRelation) {

			currentAttributeMapping.clear();

			for (wregex attributeNameRegEx : attributeNameRegExes) {

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

					if (regex_match(allWriterMetadata[i].attributeName, attributeNameRegEx)) currentAttributeMapping.push_back(i);

				}

			}

			if (currentAttributeMapping.empty()) return; // No attribute matches → DROP whole relation

			for (integer_t i : currentAttributeMapping) writerMetadata.push_back(allWriterMetadata[i]);

		} else {

			writerMetadata = allWriterMetadata;

		}

		relationalWriter->startRelation(name, writerMetadata, true);

	}

	void attribute(const string_t& value) override {

		if (filterCurrentRelation) {

			currentRecord[currentAttributeIndex] = value;

			currentAttributeIndex++;

			if (currentAttributeIndex > 0 && currentAttributeIndex % currentRecord.size() == 0) {

				for (integer_t i : currentAttributeMapping) relationalWriter->writeAttribute(currentRecord[i]);

			}

			currentAttributeIndex = currentAttributeIndex % currentRecord.size();

		} else {

			relationalWriter->writeAttribute(value);

		}

	}

	void endOfPipe() {

	}

};

}

}

}