/**
 * 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, 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 <memory>
#include <string>
#include <vector>
#include <iostream>
#include <sstream>
#include <locale>
#include <codecvt>

#include <relpipe/common/type/typedefs.h>
#include <relpipe/reader/TypeId.h>
#include <relpipe/reader/handlers/RelationalReaderStringHandler.h>
#include <relpipe/reader/handlers/AttributeMetadata.h>

namespace relpipe {
namespace out {
namespace yaml {

class YAMLHandler : public relpipe::reader::handlers::RelationalReaderStringHandler {
private:
	const char ESC = '\\';
	const char Q = '"';
	std::ostream& output;
	std::wstring_convert<std::codecvt_utf8<wchar_t>> convertor; // we generate YAML always in UTF-8 like XML?
	std::vector<relpipe::reader::handlers::AttributeMetadata> currentAttributes;
	size_t currentAttributeIndex = 0;
	bool firstRecord;

	std::string escape(const relpipe::common::type::StringX& value) {
		std::stringstream result;
		result.put(Q);
		for (char ch : convertor.to_bytes(value)) {
			if (ch == ESC) result.put(ESC).put(ch);
			else if (ch == Q) result.put(ESC).put(ch);
			else if (ch == '\n') result.put(ESC).put('n');
			else if (ch == '\r') result.put(ESC).put('r');
			else result.put(ch);
		}
		result.put(Q);
		return result.str();
	}

	std::string indent(int level) {
		std::stringstream result;
		for (int i = 0; i < level; i++) result << "  ";
		return result.str();
	}

public:

	YAMLHandler(std::ostream& output) : output(output) {
	}

	void startRelation(relpipe::common::type::StringX name, std::vector<relpipe::reader::handlers::AttributeMetadata> attributes) override {
		currentAttributes = attributes;
		currentAttributeIndex = 0;
		output << escape(name);
		output << ":" << std::endl;
		output << indent(1) << R"("attribute-metadata":)" << std::endl;
		for (auto am : attributes) output << indent(2) << R"(- "name": )" << escape(am.getAttributeName()) << std::endl << indent(2) << R"(  "type": )" << escape(am.getTypeName()) << std::endl;
		firstRecord = true;
	}

	void attribute(const relpipe::common::type::StringX& value) override {
		if (firstRecord) {
			output << indent(1) << R"("record":)" << std::endl;
			firstRecord = false;
		}

		if (currentAttributeIndex % currentAttributes.size() == 0) {
			currentAttributeIndex = 0;
			output << indent(2) << "- ";
		} else {
			output << indent(2) << "  ";
		}

		output << escape(currentAttributes[currentAttributeIndex].getAttributeName()) << ": ";

		if (currentAttributes[currentAttributeIndex].getTypeId() == relpipe::reader::TypeId::INTEGER) output << convertor.to_bytes(value) << std::endl;
		else if (currentAttributes[currentAttributeIndex].getTypeId() == relpipe::reader::TypeId::BOOLEAN) output << convertor.to_bytes(value) << std::endl;
		else output << escape(value) << std::endl;

		currentAttributeIndex++;
	}

	void endOfPipe() {
		output.flush();
	}

};

}
}
}