/*********************************************************************************************************
* Software License Agreement (BSD License)                                                               *
* Author: Sebastien Decugis <sdecugis@nict.go.jp>							 *
*													 *
* Copyright (c) 2009, WIDE Project and NICT								 *
* All rights reserved.											 *
* 													 *
* Redistribution and use of this software in source and binary forms, with or without modification, are  *
* permitted provided that the following conditions are met:						 *
* 													 *
* * Redistributions of source code must retain the above 						 *
*   copyright notice, this list of conditions and the 							 *
*   following disclaimer.										 *
*    													 *
* * Redistributions in binary form must reproduce the above 						 *
*   copyright notice, this list of conditions and the 							 *
*   following disclaimer in the documentation and/or other						 *
*   materials provided with the distribution.								 *
* 													 *
* * Neither the name of the WIDE Project or NICT nor the 						 *
*   names of its contributors may be used to endorse or 						 *
*   promote products derived from this software without 						 *
*   specific prior written permission of WIDE Project and 						 *
*   NICT.												 *
* 													 *
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED *
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A *
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR *
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 	 *
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 	 *
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR *
* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF   *
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.								 *
*********************************************************************************************************/

#include "fD.h"

const char *peer_state_str[] = { 
	  "STATE_NEW"
	, "STATE_OPEN"
	, "STATE_CLOSED"
	, "STATE_CLOSING"
	, "STATE_WAITCNXACK"
	, "STATE_WAITCNXACK_ELEC"
	, "STATE_WAITCEA"
	, "STATE_SUSPECT"
	, "STATE_REOPEN"
	, "STATE_ZOMBIE"
	};

const char * fd_pev_str(int event)
{
	switch (event) {
	#define case_str( _val )\
		case _val : return #_val
		case_str(FDEVP_TERMINATE);
		case_str(FDEVP_DUMP_ALL);
		case_str(FDEVP_MSG_INCOMING);
		case_str(FDEVP_PSM_TIMEOUT);
		
		default:
			TRACE_DEBUG(FULL, "Unknown event : %d", event);
			return "Unknown event";
	}
}


static int started = 0;
static pthread_mutex_t  started_mtx = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t   started_cnd = PTHREAD_COND_INITIALIZER;

/* Wait for start signal */
static int fd_psm_waitstart()
{
	TRACE_ENTRY("");
	CHECK_POSIX( pthread_mutex_lock(&started_mtx) );
awake:	
	if (! started) {
		pthread_cleanup_push( fd_cleanup_mutex, &started_mtx );
		CHECK_POSIX( pthread_cond_wait(&started_cnd, &started_mtx) );
		pthread_cleanup_pop( 0 );
		goto awake;
	}
	CHECK_POSIX( pthread_mutex_unlock(&started_mtx) );
	return 0;
}

/* Cancelation cleanup : set ZOMBIE state in the peer */
void cleanup_state(void * arg) 
{
	struct fd_peer * peer = (struct fd_peer *)arg;
	CHECK_PARAMS_DO( CHECK_PEER(peer), return );
	peer->p_hdr.info.pi_state = STATE_ZOMBIE;
	return;
}

/* Set timeout timer of next event */
static void psm_next_timeout(struct fd_peer * peer, int add_random, int delay)
{
	/* Initialize the timer */
	CHECK_POSIX_DO(  clock_gettime( CLOCK_REALTIME,  &peer->p_psm_timer ), ASSERT(0) );
	
	if (add_random) {
		if (delay > 2)
			delay -= 2;
		else
			delay = 0;

		/* Add a random value between 0 and 4sec */
		peer->p_psm_timer.tv_sec += random() % 4;
		peer->p_psm_timer.tv_nsec+= random() % 1000000000L;
		if (peer->p_psm_timer.tv_nsec > 1000000000L) {
			peer->p_psm_timer.tv_nsec -= 1000000000L;
			peer->p_psm_timer.tv_sec ++;
		}
	}
	
	peer->p_psm_timer.tv_sec += delay;
	
#if 0
	/* temporary for debug */
	peer->p_psm_timer.tv_sec += 10;
#endif
}

/* Wait for the next event in the PSM, or timeout */
static int psm_ev_timedget(struct fd_peer * peer, int *code, void ** data)
{
	struct fd_event * ev;
	int ret = 0;
	
	TRACE_ENTRY("%p %p %p", peer, code, data);
	
	ret = fd_fifo_timedget(peer->p_events, &ev, &peer->p_psm_timer);
	if (ret == ETIMEDOUT) {
		*code = FDEVP_PSM_TIMEOUT;
		*data = NULL;
	} else {
		CHECK_FCT( ret );
		*code = ev->code;
		*data = ev->data;
		free(ev);
	}
	
	return 0;
}

/* The state machine thread (controler) */
static void * p_psm_th( void * arg )
{
	struct fd_peer * peer = (struct fd_peer *)arg;
	int created_started = started;
	int event;
	void * ev_data;
	
	CHECK_PARAMS_DO( CHECK_PEER(peer), ASSERT(0) );
	
	pthread_cleanup_push( cleanup_state, arg );
	
	/* Set the thread name */
	{
		char buf[48];
		sprintf(buf, "PSM/%.*s", sizeof(buf) - 5, peer->p_hdr.info.pi_diamid);
		fd_log_threadname ( buf );
	}
	
	/* The state machine starts in CLOSED state */
	peer->p_hdr.info.pi_state = STATE_CLOSED;
	
	/* Wait that the PSM are authorized to start in the daemon */
	CHECK_FCT_DO( fd_psm_waitstart(), goto psm_end );
	
	/* Initialize the timer */
	if (peer->p_flags.pf_responder) {
		psm_next_timeout(peer, 0, INCNX_TIMEOUT);
	} else {
		psm_next_timeout(peer, created_started ? 0 : 1, 0);
	}
	
psm_loop:
	/* Get next event */
	CHECK_FCT_DO( psm_ev_timedget(peer, &event, &ev_data), goto psm_end );
	TRACE_DEBUG(FULL, "'%s'\t<-- '%s'\t(%p)\t'%s'",
			STATE_STR(peer->p_hdr.info.pi_state),
			fd_pev_str(event), ev_data,
			peer->p_hdr.info.pi_diamid);

	/* Now, the action depends on the current state and the incoming event */

	/* The following two states are impossible */
	ASSERT( peer->p_hdr.info.pi_state != STATE_NEW );
	ASSERT( peer->p_hdr.info.pi_state != STATE_ZOMBIE );

	/* Purge invalid events */
	if (!CHECK_EVENT(event)) {
		TRACE_DEBUG(INFO, "Invalid event received in PSM '%s' : %d", peer->p_hdr.info.pi_diamid, event);
		goto psm_loop;
	}

	/* Handle the (easy) debug event now */
	if (event == FDEVP_DUMP_ALL) {
		fd_peer_dump(peer, ANNOYING);
		goto psm_loop;
	}

	/* Requests to terminate the peer object */
	if (event == FDEVP_TERMINATE) {
		switch (peer->p_hdr.info.pi_state) {
			case STATE_CLOSING:
			case STATE_WAITCNXACK:
			case STATE_WAITCNXACK_ELEC:
			case STATE_WAITCEA:
			case STATE_SUSPECT:
				/* In these cases, we just cleanup the peer object and terminate now */
				TODO("Cleanup the PSM: terminate connection object, ...");
			case STATE_CLOSED:
				/* Then we just terminate the PSM */
				goto psm_end;
				
			case STATE_OPEN:
			case STATE_REOPEN:
				/* We cannot just close the conenction, we have to send a DPR first */
				TODO("Send DPR, mark the peer as CLOSING");
				goto psm_loop;
		}
	}
	
	/* MSG_RECEIVED: fd_p_expi_update(struct fd_peer * peer ) */
	/* If timeout or OPEN : call cb if defined */

	/* Default action : the handling has not yet been implemented. */
	TODO("Missing handler in PSM : '%s'\t<-- '%s'", STATE_STR(peer->p_hdr.info.pi_state), fd_pev_str(event));
	if (event == FDEVP_PSM_TIMEOUT) {
		/* We have not handled timeout in this state, let's postpone next alert */
		psm_next_timeout(peer, 0, 60);
	}
	
	goto psm_loop;
	
psm_end:
	pthread_cleanup_pop(1); /* set STATE_ZOMBIE */
	return NULL;
}	
	
	


/* Create the PSM thread of one peer structure */
int fd_psm_begin(struct fd_peer * peer )
{
	TRACE_ENTRY("%p", peer);
	
	/* Check the peer and state are OK */
	CHECK_PARAMS( CHECK_PEER(peer) && (peer->p_hdr.info.pi_state == STATE_NEW) );
	
	/* Create the PSM controler thread */
	CHECK_POSIX( pthread_create( &peer->p_psm, NULL, p_psm_th, peer ) );
	
	/* We're done */
	return 0;
}

/* End the PSM (clean ending) */
int fd_psm_terminate(struct fd_peer * peer )
{
	TRACE_ENTRY("%p", peer);
	CHECK_PARAMS( CHECK_PEER(peer) );
	if (peer->p_hdr.info.pi_state != STATE_ZOMBIE) {
		CHECK_FCT( fd_event_send(peer->p_events, FDEVP_TERMINATE, NULL) );
	} else {
		TRACE_DEBUG(FULL, "Peer '%s' was already terminated", peer->p_hdr.info.pi_diamid);
	}
	return 0;
}

/* End the PSM violently */
void fd_psm_abord(struct fd_peer * peer )
{
	TRACE_ENTRY("%p", peer);
	TODO("Cancel PSM thread");
	TODO("Cancel IN thread");
	TODO("Cancel OUT thread");
	TODO("Cleanup the peer connection object");
	TODO("Cleanup the message queues (requeue)");
	return;
}

/* Allow the state machines to start */
int fd_psm_start()
{
	TRACE_ENTRY("");
	CHECK_POSIX( pthread_mutex_lock(&started_mtx) );
	started = 1;
	CHECK_POSIX( pthread_cond_broadcast(&started_cnd) );
	CHECK_POSIX( pthread_mutex_unlock(&started_mtx) );
	return 0;
}