/** Message paths
 *
 * @file
 * @author Steffen Vogel <post@steffenvogel.de>
 * @copyright 2014-2022, Institute for Automation of Complex Power Systems, EONERC
 * @license Apache 2.0
 *********************************************************************************/

#pragma once

#include <bitset>

#include <uuid/uuid.h>
#include <pthread.h>
#include <jansson.h>
#include <spdlog/fmt/ostr.h>

#include <villas/list.hpp>
#include <villas/queue.h>
#include <villas/pool.hpp>
#include <villas/common.hpp>
#include <villas/task.hpp>
#include <villas/node_list.hpp>
#include <villas/colors.hpp>
#include <villas/node.hpp>
#include <villas/path_source.hpp>
#include <villas/signal_list.hpp>
#include <villas/mapping_list.hpp>
#include <villas/path_destination.hpp>

#include <villas/log.hpp>

/* Forward declarations */
struct pollfd;

namespace villas {
namespace node {

/* Forward declarations */
class Node;

/** The datastructure for a path. */
class Path {
	friend PathSource;
	friend SecondaryPathSource;
	friend PathDestination;

protected:
	void * runSingle();
	void * runPoll();

	static
	void * runWrapper(void *arg);

	void startPoll();

	static int id;

public:
	enum State state;		/**< Path state. */

	/** The register mode determines under which condition the path is triggered. */
	enum class Mode {
		ANY,				/**< The path is triggered whenever one of the sources receives samples. */
		ALL				/**< The path is triggered only after all sources have received at least 1 sample. */
	} mode;					/**< Determines when this path is triggered. */

	uuid_t uuid;

	std::vector<struct pollfd> pfds;

	struct Pool pool;
	struct Sample *last_sample;
	int last_sequence;

	NodeList masked;
	MappingList mappings;			/**< List of all input mappings. */
	PathSourceList sources;			/**< List of all incoming nodes. */
	PathDestinationList destinations;	/**< List of all outgoing nodes. */
	HookList hooks;				/**< List of processing hooks. */
	SignalList::Ptr signals;		/**< List of signals which this path creates. */

	struct Task timeout;

	double rate;			/**< A timeout for */
	int affinity;			/**< Thread affinity. */
	bool enabled;			/**< Is this path enabled? */
	int poll;			/**< Weather or not to use poll(2). */
	bool reversed;			/**< This path has a matching reverse path. */
	bool builtin;			/**< This path should use built-in hooks by default. */
	int original_sequence_no;	/**< Use original source sequence number when multiplexing */
	unsigned queuelen;		/**< The queue length for each path_destination::queue */

	pthread_t tid;			/**< The thread id for this path. */
	json_t *config;			/**< A JSON object containing the configuration of the path. */

	Logger logger;

	std::bitset<MAX_SAMPLE_LENGTH> mask;		/**< A mask of PathSources which are enabled for poll(). */
	std::bitset<MAX_SAMPLE_LENGTH> received;	/**< A mask of PathSources for which we already received samples. */

	/** Custom formatter for spdlog */
	template<typename OStream>
	friend OStream &operator<<(OStream &os, const Path &p)
	{
		if (p.sources.size() > 1)
			os << "[ ";

		for (auto ps : p.sources)
			os << ps->getNode()->getNameShort() << " ";

		if (p.sources.size() > 1)
			os << "] ";

		os << CLR_MAG("=>");

		if (p.destinations.size() != 1)
			os << " [";

		for (auto pd : p.destinations)
			os << " " << pd->getNode()->getNameShort();

		if (p.destinations.size() != 1)
			os << " ]";

		return os;
	}

	std::string toString()
	{
		std::stringstream ss;
		ss << *this;
		return ss.str();
	}

	Path();
	~Path();

	void prepare(NodeList &nodes);

	/** Check if path configuration is proper. */
	void check();

	/** Check prepared path. */
	void checkPrepared();

	/** Start a path.
	*
	* Start a new pthread for receiving/sending messages over this path.
	*/
	void start();

	/** Stop a path. */
	void stop();

	/** Get a list of signals which is emitted by the path. */
	SignalList::Ptr getOutputSignals(bool after_hooks = true);

	unsigned getOutputSignalsMaxCount();

	/** Parse a single path and add it to the global configuration.
	*
	* @param json A JSON object containing the configuration of the path.
	* @param p Pointer to the allocated memory for this path
	* @param nodes A linked list of all existing nodes
	* @retval 0 Success. Everything went well.
	* @retval <0 Error. Something went wrong.
	*/
	void parse(json_t *json, NodeList &nodes, const uuid_t sn_uuid);

	void parseMask(json_t *json_mask, NodeList &nodes);

	bool isSimple() const;
	bool isMuxed() const;

	bool isEnabled() const
	{
		return enabled;
	}

	bool isReversed() const
	{
		return reversed;
	}

	State getState() const
	{
		return state;
	}

	/** Get the UUID of this path. */
	const uuid_t & getUuid() const
	{
		return uuid;
	}

	json_t * toJson() const;
};

} /* namespace node */
} /* namespace villas */