/**
 * 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 <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 GrepHandler : public RelationalReaderStringHadler {
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:

	GrepHandler(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() {

	}

};

}
}
}