/*
 * Copyright (C) 2012 Smile Communications, jason.penton@smilecoms.com
 * Copyright (C) 2012 Smile Communications, richard.good@smilecoms.com
 *
 * The initial version of this code was written by Dragos Vingarzan
 * (dragos(dot)vingarzan(at)fokus(dot)fraunhofer(dot)de and the
 * Fraunhofer FOKUS Institute. It was and still is maintained in a separate
 * branch of the original SER. We are therefore migrating it to
 * Kamailio/SR and look forward to maintaining it from here on out.
 * 2011/2012 Smile Communications, Pty. Ltd.
 * ported/maintained/improved by
 * Jason Penton (jason(dot)penton(at)smilecoms.com and
 * Richard Good (richard(dot)good(at)smilecoms.com) as part of an
 * effort to add full IMS support to Kamailio/SR using a new and
 * improved architecture
 *
 * NB: A lot of this code was originally part of OpenIMSCore,
 * FhG Fokus.
 * Copyright (C) 2004-2006 FhG Fokus
 * Thanks for great work! This is an effort to
 * break apart the various CSCF functions into logically separate
 * components. We hope this will drive wider use. We also feel
 * that in this way the architecture is more complete and thereby easier
 * to manage in the Kamailio/SR environment
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * Kamailio 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 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include "diameter_api.h"
#include "peer.h"
#include "peermanager.h"
#include "receiver.h"
#include "transaction.h"
#include "api_process.h"
#include "routing.h"
#include "peerstatemachine.h"
#include "globals.h"

extern dp_config *config; /**< Configuration for this diameter peer 	*/
extern unsigned int *latency_threshold_p; /**<max delay for Diameter call */

/* CALLBACKS */
extern handler_list *handlers;	  /**< list of handlers */
extern gen_lock_t *handlers_lock; /**< lock for list of handlers */

/**
 * Add a handler function for incoming requests.
 * @param f - the callback function
 * @param param - generic parameter to be used when calling the callback functions
 * @returns 1 on success, 0 on failure
 */
int AAAAddRequestHandler(AAARequestHandler_f *f, void *param)
{
	handler *h = shm_malloc(sizeof(handler));
	if(!h) {
		LM_ERR("error allocating %ld bytes in shm\n",
				(long int)sizeof(handler));
		return 0;
	}
	h->type = REQUEST_HANDLER;
	h->handler.requestHandler = f;
	h->param = param;
	h->next = 0;
	lock_get(handlers_lock);
	h->prev = handlers->tail;
	if(handlers->tail)
		handlers->tail->next = h;
	handlers->tail = h;
	if(!handlers->head)
		handlers->head = h;
	lock_release(handlers_lock);
	return 1;
}

/**
 * Add a handler function for incoming responses.
 * @param f - the callback function
 * @param param - generic parameter to be used when calling the callback functions
 * @returns 1 on success, 0 on failure
 */
int AAAAddResponseHandler(AAAResponseHandler_f *f, void *param)
{
	handler *h = shm_malloc(sizeof(handler));
	if(!h) {
		LM_ERR("error allocating %ld bytes in shm\n",
				(long int)sizeof(handler));
		return 0;
	}
	h->type = RESPONSE_HANDLER;
	h->handler.responseHandler = f;
	h->param = param;
	h->next = 0;
	lock_get(handlers_lock);
	h->prev = handlers->tail;
	if(handlers->tail)
		handlers->tail->next = h;
	handlers->tail = h;
	if(!handlers->head)
		handlers->head = h;
	lock_release(handlers_lock);
	return 1;
}


/* MESSAGE SENDING */

/**
 * Send an AAAMessage asynchronously.
 * When the response is received, the callback_f(callback_param,...) is called.
 * @param message - the request to be sent
 * @param peer_id - FQDN of the peer to send
 * @param callback_f - callback to be called on transactional response or transaction timeout
 * @param callback_param - generic parameter to call the transactional callback function with
 * @returns 1 on success, 0 on failure
 * \todo remove peer_id and add Realm routing
 */
AAAReturnCode AAASendMessage(AAAMessage *message,
		AAATransactionCallback_f *callback_f, void *callback_param)
{
	cdp_session_t *cdp_session;
	peer *p;
	cdp_session = cdp_get_session(message->sessionId->data);

	p = get_routing_peer(cdp_session, message);
	if(cdp_session) {
		AAASessionsUnlock(cdp_session->hash);
	}
	if(!p) {
		LM_ERR("Can't find a suitable connected peer in the routing table.\n");
		goto error;
	}
	LM_DBG("Found diameter peer [%.*s] from routing table\n", p->fqdn.len,
			p->fqdn.s);
	if(p->state != I_Open && p->state != R_Open) {
		LM_ERR("Peer not connected to %.*s\n", p->fqdn.len, p->fqdn.s);
		goto error;
	}
	/* only add transaction following when required */
	if(callback_f) {
		if(is_req(message))
			cdp_add_trans(message, callback_f, callback_param,
					config->transaction_timeout, 1);
		else
			LM_ERR("can't add transaction callback for answer.\n");
	}

	//	if (!peer_send_msg(p,message))
	if(!sm_process(p, Send_Message, message, 0, 0))
		goto error;

	return 1;
error:
	AAAFreeMessage(&message);
	return 0;
}

/**
 * Send an AAAMessage asynchronously.
 * When the response is received, the callback_f(callback_param,...) is called.
 * @param message - the request to be sent
 * @param peer_id - FQDN of the peer to send
 * @param callback_f - callback to be called on transactional response or transaction timeout
 * @param callback_param - generic parameter to call the transactional callback function with
 * @returns 1 on success, 0 on failure
 * \todo remove peer_id and add Realm routing
 */
AAAReturnCode AAASendMessageToPeer(AAAMessage *message, str *peer_id,
		AAATransactionCallback_f *callback_f, void *callback_param)
{
	peer *p;
	p = get_peer_by_fqdn(peer_id);
	if(!p) {
		LM_ERR("Peer unknown %.*s\n", peer_id->len, peer_id->s);
		goto error;
	}
	if(p->state != I_Open && p->state != R_Open) {
		LM_ERR("Peer not connected to %.*s\n", peer_id->len, peer_id->s);
		goto error;
	}
	/* only add transaction following when required */
	if(callback_f) {
		if(is_req(message))
			cdp_add_trans(message, callback_f, callback_param,
					config->transaction_timeout, 1);
		else
			LM_ERR("can't add transaction callback for answer.\n");
	}

	p->last_selected = time(NULL);
	if(!sm_process(p, Send_Message, message, 0, 0))
		goto error;

	return 1;
error:
	AAAFreeMessage(&message);
	return 0;
}


/**
 * Generic callback used by AAASendRecvMessage() to block until a transactional response
 * is received.
 * The AAASendRecvMessage() is basically an AAASendMessage() that has a callback
 * (this function) that blocks until a transactional response or timeout is received and
 * then it returns that.
 *
 * @param is_timeout - if this is a time-out or response event
 * @param param - generic parameter to call the transactional callback function with
 * @param ans - the answer for the callback
 */
void sendrecv_cb(
		int is_timeout, void *param, AAAMessage *ans, long elapsed_msecs)
{
	if(sem_release((gen_sem_t *)param) < 0)
		LM_ERR("Failed to unlock a transactional sendrecv! > %s\n",
				strerror(errno));
}

/**
 * Send an AAAMessage synchronously.
 * This blocks until a response is received or a transactional time-out happens.
 * @param message - the request to be sent
 * @param peer_id - FQDN of the peer to send
 * @returns 1 on success, 0 on failure
 * \todo remove peer_id and add Realm routing
 * \todo replace the busy-waiting lock in here with one that does not consume CPU
 */
AAAMessage *AAASendRecvMessage(AAAMessage *message)
{
	peer *p;
	gen_sem_t *sem = 0;
	cdp_trans_t *t;
	AAAMessage *ans;
	struct timeval start, stop;
	long elapsed_usecs = 0, elapsed_millis = 0;
	cdp_session_t *cdp_session;

	gettimeofday(&start, NULL);
	cdp_session = cdp_get_session(message->sessionId->data);
	p = get_routing_peer(cdp_session, message);
	if(cdp_session) {
		AAASessionsUnlock(cdp_session->hash);
	}
	if(!p) {
		LM_ERR("Can't find a suitable connected peer in the routing table.\n");
		goto error;
	}
	if(p->state != I_Open && p->state != R_Open) {
		LM_ERR("Peer not connected to %.*s\n", p->fqdn.len, p->fqdn.s);
		goto error;
	}


	if(is_req(message)) {
		sem_new(sem, 0);
		t = cdp_add_trans(message, sendrecv_cb, (void *)sem,
				config->transaction_timeout, 0);

		if(!sm_process(p, Send_Message, message, 0, 0)) {
			sem_free(sem);
			goto error;
		}

		/* block until callback is executed */
		while(sem_get(sem) < 0) {
			if(shutdownx && (*shutdownx))
				goto error;
			LM_WARN("interrupted by signal or something > %s\n",
					strerror(errno));
		}
		sem_free(sem);
		gettimeofday(&stop, NULL);
		elapsed_usecs = (stop.tv_sec - start.tv_sec) * 1000000
						+ (stop.tv_usec - start.tv_usec);
		elapsed_millis = elapsed_usecs / 1000;
		if(elapsed_millis > *latency_threshold_p) {
			LM_ERR("CDP response to Send_Message took too long (>%dms) - "
				   "[%ldms]\n",
					*latency_threshold_p, elapsed_millis);
		}
		ans = t->ans;
		cdp_free_trans(t);
		return ans;
	} else {
		LM_ERR("can't add wait for answer to answer.\n");
		goto error;
	}


error:
out_of_memory:
	AAAFreeMessage(&message);
	return 0;
}

/**
 * Send an AAAMessage synchronously.
 * This blocks until a response is received or a transactional time-out happens.
 * @param message - the request to be sent
 * @param peer_id - FQDN of the peer to send
 * @returns 1 on success, 0 on failure
 * \todo remove peer_id and add Realm routing
 * \todo replace the busy-waiting lock in here with one that does not consume CPU
 */
AAAMessage *AAASendRecvMessageToPeer(AAAMessage *message, str *peer_id)
{
	peer *p;
	gen_sem_t *sem;
	cdp_trans_t *t;
	AAAMessage *ans;
	struct timeval start, stop;
	long elapsed_usecs = 0, elapsed_millis = 0;

	gettimeofday(&start, NULL);

	p = get_peer_by_fqdn(peer_id);
	if(!p) {
		LM_ERR("Peer unknown %.*s\n", peer_id->len, peer_id->s);
		goto error;
	}
	if(p->state != I_Open && p->state != R_Open) {
		LM_ERR("Peer not connected to %.*s\n", peer_id->len, peer_id->s);
		goto error;
	}

	if(is_req(message)) {
		sem_new(sem, 0);
		t = cdp_add_trans(message, sendrecv_cb, (void *)sem,
				config->transaction_timeout, 0);

		//		if (!peer_send_msg(p,message)) {
		if(!sm_process(p, Send_Message, message, 0, 0)) {
			sem_free(sem);
			goto error;
		}
		/* block until callback is executed */
		while(sem_get(sem) < 0) {
			if(shutdownx && (*shutdownx))
				goto error;
			LM_WARN("interrupted by signal or something > %s\n",
					strerror(errno));
		}

		gettimeofday(&stop, NULL);
		elapsed_usecs = (stop.tv_sec - start.tv_sec) * 1000000
						+ (stop.tv_usec - start.tv_usec);
		elapsed_millis = elapsed_usecs / 1000;
		if(elapsed_millis > *latency_threshold_p) {
			LM_ERR("CDP response to Send_Message took too long (>%dms) - "
				   "[%ldms]\n",
					*latency_threshold_p, elapsed_millis);
		}
		sem_free(sem);

		ans = t->ans;
		cdp_free_trans(t);
		return ans;
	} else {
		LM_ERR("can't add wait for answer to answer.\n");
		goto error;
	}


error:
out_of_memory:
	AAAFreeMessage(&message);
	return 0;
}
