/**

 * Relational pipes

 * Copyright © 2021 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 <sstream>

#include <iomanip>

#include "ASN1ContentHandler.h"

#include "XMLContentHandler.h"

namespace relpipe {

namespace in {

namespace asn1 {

namespace lib {

/**

 * Converts ASN.1 events to XML SAX events.

 * 

 * Does not need to know anything about the model/schema – works with generic events (nodes).

 */

class GenericASN1ContentHandler : public ASN1ContentHandler {

private:

	XMLContentHandlerProxy handlers;

	std::vector<std::string> getCommonAttributes(const Header& header, std::vector<std::string> attributes = {}) {

		std::string tag = std::to_string(header.tag);

		std::string tagClass = std::to_string((uint64_t) header.tagClass);

		std::string pc = std::to_string((uint8_t) header.pc);

		if (header.tagClass == TagClass::Universal) tagClass = "universal";

		else if (header.tagClass == TagClass::ContextSpecific) tagClass = "context";

		else if (header.tagClass == TagClass::Application) tagClass = "application";

		else if (header.tagClass == TagClass::Private) tagClass = "private";

		// if (header.pc == PC::Constructed) pc = "constructed";

		// else if (header.pc == PC::Primitive) pc = "primitive";

		attributes.push_back("tag");

		attributes.push_back(tag);

		// attributes.push_back("pc");

		// attributes.push_back(pc);

		attributes.push_back("class");

		attributes.push_back(tagClass);

		return attributes;

	}

	/**

	 * @param header

	 * @param value an octet string

	 * @return original value if octet string was a text string; otherwise an empty string

	 */

	const std::string getText(const Header& header, const std::string& value) {

		// TODO: support also UTF-8

		for (uint8_t b : value) if (b < 32 || b >= 127) return "";

		return value;

	}

public:

	void addHandler(std::shared_ptr<XMLContentHandler> handler) {

		handlers.addHandler(handler);

	}

	virtual ~GenericASN1ContentHandler() {

	}

	void writeStreamStart() override {

	}

	void writeStreamEnd() override {

		handlers.writeEndElement();

	}

	void writeCollectionStart(const Header& header) override {

		if (header.tag == UniversalType::Sequence) handlers.writeStartElement("sequence", getCommonAttributes(header));

		else if (header.tag == UniversalType::Set) handlers.writeStartElement("set", getCommonAttributes(header));

		else if (header.tag == UniversalType::OctetString || header.tag == UniversalType::BitString) handlers.writeStartElement("encapsulated", getCommonAttributes(header));

		else handlers.writeStartElement("constructed", getCommonAttributes(header));

	}

	void writeCollectionEnd() override {

		handlers.writeEndElement();

	}

	void writeBoolean(const Header& header, bool value) override {

		handlers.writeStartElement("boolean", getCommonAttributes(header));

		handlers.writeCharacters(value ? "true" : "false");

		handlers.writeEndElement();

	}

	void writeNull(const Header& header) override {

		handlers.writeStartElement("null", getCommonAttributes(header));

		handlers.writeEndElement();

	}

	void writeInteger(const Header& header, Integer value) override {

		handlers.writeStartElement("integer", getCommonAttributes(header,{"hex", value.toHex()}));

		handlers.writeCharacters(value.toString());

		handlers.writeEndElement();

	}

	void writeTextString(const Header& header, std::string value) override {

		handlers.writeStartElement("text-string", getCommonAttributes(header));

		handlers.writeCharacters(value);

		handlers.writeEndElement();

	}

	void writeOctetString(const Header& header, std::string value) override {

		std::vector<std::string> attributes = getCommonAttributes(header,{"length", std::to_string(value.size())});

		std::string text = getText(header, value);

		if (text.size()) {

			attributes.push_back("text");

			attributes.push_back(text);

		}

		std::stringstream hex;

		hex << std::hex << std::setfill('0');

		for (uint8_t b : value) hex << std::setw(2) << (int) b;

		handlers.writeStartElement("octet-string", attributes);

		handlers.writeCharacters(hex.str());

		handlers.writeEndElement();

	}

	void writeBitString(const Header& header, std::vector<bool> value) override {

		std::stringstream bits;

		for (bool b : value) bits << (int) b;

		// for (bool b : value) bits << (b ? ':' : '.'); // TODO: configurable true/false symbols?

		handlers.writeStartElement("bit-string", getCommonAttributes(header,{"length", std::to_string(value.size())}));

		handlers.writeCharacters(bits.str());

		handlers.writeEndElement();

	}

	void writeOID(const Header& header, ObjectIdentifier value) override {

		// TODO: optionally expand into separate elements with additional metadata

		handlers.writeStartElement("oid", getCommonAttributes(header)); // TODO: {"length", std::to_string(value.size())}

		handlers.writeCharacters(value.toString());

		handlers.writeEndElement();

	}

	void writeDateTime(const Header& header, DateTime value) override {

		handlers.writeStartElement("date-time", getCommonAttributes(header));

		handlers.writeCharacters(value.toString());

		handlers.writeEndElement();

	}

	void writeSpecific(const Header& header, std::string value) override {

		std::stringstream hex;

		hex << std::hex << std::setfill('0');

		for (uint8_t b : value) hex << std::setw(2) << (int) b;

		std::stringstream ascii;

		for (uint8_t b : value) ascii << (b >= 32 && b < 127 ? (char) b : '.'); // TODO: configurable unsupported symbol?

		handlers.writeStartElement("specific", getCommonAttributes(header,{"length", std::to_string(value.size()), "hex", hex.str()}));

		handlers.writeCharacters(ascii.str());

		handlers.writeEndElement();

	}

};

}

}

}

}