/** Message paths
 *
 * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
 * @copyright 2014, Institute for Automation of Complex Power Systems, EONERC
 * @file path.h
 */

#ifndef _PATH_H_
#define _PATH_H_

#include <pthread.h>

#include "config.h"
#include "node.h"
#include "msg.h"

/** The datastructure for a path
 *
 * @todo Add support for multiple outgoing nodes
 */
struct path
{
	/// Pointer to the incoming node
	struct node *in;
	/// Pointer to the outgoing node
	struct node *out;

	/** If non NULL this function is called for every received message.
	 *
	 * This hook can be used to filter messages on a user-defined criteria.
	 * If the function has a non-zero return value the message will be dropped.
	 */
	int (*hook)(struct msg *m);

	/// Counter for received messages
	unsigned int received;

	/// Counter for messages which arrived reordered
	unsigned int delayed;

	/// Counter for messages which arrived multiple times
	unsigned int duplicated;

	/// Last known message number
	unsigned int sequence;

	/// The thread for this path
	pthread_t tid;
};

/** Setup a new path.
 *
 * @param p A pointer to the path structure
 * @param in The node we are receiving messages from
 * @param out The destination node
 * @return
 *  - 0 on success
 *  - otherwise an error occured
 */
int path_create(struct path *p, struct node *in, struct node *out);

/** Start a path.
 *
 * Start a new pthread for receiving/sending messages over this path.
 *
 * @param p A pointer to the path struct
 * @return
 *  - 0 on success
 *  - otherwise an error occured
 */
int path_start(struct path *p);

/** Stop a path.
 *
 * @param p A pointer to the path struct
 * @return
 *  - 0 on success
 *  - otherwise an error occured
 */
int path_stop(struct path *p);

#endif /* _PATH_H_ */