/** Simple WebSocket relay facilitating client-to-client connections.
 *
 * @file
 * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
 * @copyright 2014-2020, Institute for Automation of Complex Power Systems, EONERC
 * @license GNU General Public License (version 3)
 *
 * VILLASnode
 *
 * 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
 * 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/>.
 *********************************************************************************/

#include <vector>
#include <memory>

#include <spdlog/spdlog.h>
#include <uuid/uuid.h>

#ifndef UUID_STR_LEN
  #define UUID_STR_LEN   37
#endif

#include <libwebsockets.h>

namespace villas {
namespace node {
namespace tools {

/* Forward declarations */
lws_callback_function protocol_cb, http_protocol_cb;
class Relay;
class RelaySession;
class RelayConnection;

class InvalidUrlException { };

class Frame : public std::vector<uint8_t> {
public:
	Frame() {
		/* lws_write() requires LWS_PRE bytes in front of the payload */
		insert(end(), LWS_PRE, 0);
	}

	uint8_t * data() {
		return std::vector<uint8_t>::data() + LWS_PRE;
	}

	size_type size() {
		return std::vector<uint8_t>::size() - LWS_PRE;
	}
};

class RelaySession {

	friend RelayConnection;
	friend Relay;

public:
	typedef std::string Identifier;

protected:
	time_t created;
	uuid_t uuid;


	Identifier identifier;

	std::map<lws *, RelayConnection *> connections;

	int connects;

	static std::map<std::string, RelaySession *> sessions;

public:
	static RelaySession * get(lws *wsi);

	RelaySession(Identifier sid);

	~RelaySession();

	json_t * toJson() const;
};

class RelayConnection {

protected:
	lws *wsi;

	std::shared_ptr<Frame> currentFrame;

	std::queue<std::shared_ptr<Frame>> outgoingFrames;

	RelaySession *session;

	char name[128];
	char ip[128];

	size_t created;
	size_t bytes_recv;
	size_t bytes_sent;

	size_t frames_recv;
	size_t frames_sent;

	bool loopback;

public:
	RelayConnection(lws *w, bool lo);
	~RelayConnection();

	json_t * toJson() const;

	void write();
	void read(void *in, size_t len);
};

class Relay : public Tool {

public:
	Relay(int argc, char *argv[]);

protected:
	std::atomic<bool> stop;

	/** The libwebsockets server context. */
	lws_context *context;

	/** The libwebsockets vhost. */
	lws_vhost *vhost;

	bool loopback;
	int port;
	std::string protocol;

	/** List of libwebsockets protocols. */
	std::vector<lws_protocols> protocols;

	/** List of libwebsockets extensions. */
	static const std::vector<lws_extension> extensions;

	static const lws_http_mount mount;

	static void logger_cb(int level, const char *msg);

	static int http_protocol_cb(lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len);

	static int protocol_cb(lws *wsi, enum lws_callback_reasons reason, void *user, void *in, size_t len);

	void usage();

	void parse();

	int main();

	void handler(int signal, siginfo_t *sinfo, void *ctx)
	{
		stop = true;
	}
};

} // namespace tools
} // namespace node
} // namespace villas