/*************************************************************************
* (C) 2011 AITNET ltd - Sofia/Bulgaria - <misho@aitbg.com>
*  by Michael Pounov <misho@openbsd-bg.org>
*
* $Author: misho $
* $Id: mqttd_calls.c,v 1.5 2017/10/08 22:49:25 misho Exp $
*
**************************************************************************
The ELWIX and AITNET software is distributed under the following
terms:

All of the documentation and software included in the ELWIX and AITNET
Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>

Copyright 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
	by Michael Pounov <misho@elwix.org>.  All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. 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.
3. All advertising materials mentioning features or use of this software
   must display the following acknowledgement:
This product includes software developed by Michael Pounov <misho@elwix.org>
ELWIX - Embedded LightWeight unIX and its contributors.
4. Neither the name of AITNET nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY AITNET 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 REGENTS 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 "global.h"
#include "mqttd.h"
#include "utils.h"
#include "rtlm.h"
#include "mqttd_calls.h"


static inline ait_val_t *
mkPkt(void * __restrict data, int dlen)
{
	ait_val_t *p = NULL;

	if (!(p = ait_allocVar())) {
		EVERBOSE(7, "Error:: in send packet prepare #%d - %s", 
				elwix_GetErrno(), elwix_GetError());
		return NULL;
	}

	if (data && dlen > 0)
		AIT_SET_BUF(p, data, dlen);

	return p;
}

static inline void
freePkt(ait_val_t ** __restrict p)
{
	if (!p)
		return;

	ait_freeVar(p);
}

static void *
sendPacket(sched_task_t *task)
{
	ait_val_t *p = TASK_ARG(task);
	register int n, slen;
	u_char *pos;

	if (!p || AIT_ISEMPTY(p)) {
		EVERBOSE(9, "Error:: invalid packet or found empty content ...");
		return NULL;
	}

	EVERBOSE(7, "Send packet length %d for socket %d\n", AIT_LEN(p), (u_int) TASK_FD(task));

	for (slen = AIT_LEN(p), pos = AIT_GET_BUF(p); slen > 0; slen -= n, pos += n) {
		n = send(TASK_FD(task), pos, slen, MSG_NOSIGNAL);
		if (n == -1) {
			ESYSERR(0);
			break;
		}
	}

	freePkt(&p);
	return NULL;
}

static int
search4send(struct tagSession * __restrict sess, const char *topic, int datlen, char qos)
{
	regex_t re;
	regmatch_t match;
	ait_val_t *p = NULL;
	struct tagSession *s = NULL;
	struct tagStore *st_, *st = NULL;
	char szStr[STRSIZ];
	int ret;

	assert(sess);

	TAILQ_FOREACH(s, &Sessions, sess_node) {
		SLIST_FOREACH_SAFE(st, &s->sess_subscr, st_node, st_) {
			/* check for QoS */
			if (st->st_subscr.sub_ret >= qos) {
				if ((ret = regcomp(&re, st->st_subscr.sub_topic.msg_base, REG_EXTENDED))) {
					regerror(ret, &re, szStr, sizeof szStr);
					regfree(&re);
					EVERBOSE(3, "Error:: regcomp(%s) %s\n", (char*)
							st->st_subscr.sub_topic.msg_base, szStr);
				}
				if (!regexec(&re, topic, 1, &match, 0)) {
					/* MATCH */
					p = mkPkt(sess->sess_buf->msg_base, datlen);
					schedWrite(root, sendPacket, p, s->sess_sock, NULL, 0);
				}

				regfree(&re);
			}
		}
	}

	return 0;
}

/* --------------------------------------------------- */

void *
sendRetain(sched_task_t *task)
{
	mqtt_subscr_t *subs, *s;
	struct tagSession *sess;
	int siz;

	ETRACE();

	assert(task);

	sess = TASK_ARG(task);
	assert(sess);

	if (!sess->sess_buf) {
		EVERBOSE(9, "WARNING! No allocated buffer!?!\n");
		return NULL;
	}

	subs = call.ReadPUB_topic(&cfg, pub, "%", "%", 1);
	if (!subs)
		return NULL;

	for (s = subs; s && s->sub_topic.msg_base; s++) {
		siz = s->sub_value.msg_len;
		memcpy(sess->sess_buf->msg_base, s->sub_value.msg_base, 
				MIN(sess->sess_buf->msg_len, s->sub_value.msg_len));
		EVERBOSE(7, "Sending retain message %d bytes, QoS %hhd topic '%s' data length %d\n", 
				siz, s->sub_ret, (char*) s->sub_topic.msg_base, s->sub_value.msg_len);
		if (siz > 0)
			search4send(sess, s->sub_topic.msg_base, siz, s->sub_ret);
	}

	mqtt_subFree(&subs);
	return NULL;
}

int
pubWill(struct tagSession * __restrict sess)
{
	int datlen;

	ETRACE();

	/* prepare will packet */
	datlen = mqtt_msgPUBLISH(sess->sess_buf, sess->sess_will.topic, 0xDEAD, 0, 1, 0, 
			sess->sess_will.msg, sess->sess_will.msg ? strlen(sess->sess_will.msg) : 0);
	if (datlen == -1)
		return -1;	/* error */

	return search4send(sess, sess->sess_will.topic, datlen, MQTT_QOS_ACK);
}

static int
pubOnce(struct tagSession *sess, char * __restrict psTopic, int datlen)
{
	return search4send(sess, psTopic, datlen, MQTT_QOS_ONCE);
}

static int
pubAck(struct tagSession *sess, u_short mid, char * __restrict psTopic, int datlen)
{
	struct mqtthdr *hdr = (struct mqtthdr*) sess->sess_buf->msg_base;

	/* write topic to database */
	call.DeletePUB_topic(&cfg, pub, sess->sess_cid, mid, psTopic, sess->sess_user, 
			sess->sess_addr, hdr->mqtt_msg.retain);
	call.WritePUB_topic(&cfg, pub, sess->sess_cid, mid, psTopic, 
			sess->sess_buf->msg_base, datlen, sess->sess_user, sess->sess_addr, 
			hdr->mqtt_msg.qos, hdr->mqtt_msg.retain);

	search4send(sess, psTopic, datlen, MQTT_QOS_ACK);

	/* delete not retain message */
	call.DeletePUB_topic(&cfg, pub, sess->sess_cid, mid, psTopic, sess->sess_user, 
			sess->sess_addr, 0);
	return 0;
}

static int
pubExactly(struct tagSession *sess, u_short mid, char * __restrict psTopic, int datlen)
{
	struct mqtthdr *hdr = (struct mqtthdr*) sess->sess_buf->msg_base;

	/* write topic to database */
	call.DeletePUB_topic(&cfg, pub, sess->sess_cid, mid, psTopic, sess->sess_user, 
			sess->sess_addr, hdr->mqtt_msg.retain);
	call.WritePUB_topic(&cfg, pub, sess->sess_cid, mid, psTopic, 
			sess->sess_buf->msg_base, datlen, sess->sess_user, sess->sess_addr, 
			hdr->mqtt_msg.qos, hdr->mqtt_msg.retain);

	return search4send(sess, psTopic, datlen, MQTT_QOS_EXACTLY);
}


int
cmdPUBLISH(void *srv, int len, void *arg)
{
	struct mqtthdr *hdr;
	struct tagSession *sess = (struct tagSession*) arg;
	char szTopic[STRSIZ] = { 0 };
	int siz = 0;
	u_short mid = 0;
	ait_val_t *p = NULL;

	ETRACE();

	if (!sess)
		return -1;

	EVERBOSE(5, "Exec PUBLISH session");
	siz = mqtt_readPUBLISH(sess->sess_buf, szTopic, sizeof szTopic, &mid, NULL);
	if (siz == -1) {
		EVERBOSE(5, "Error:: in readPUBLISH #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		return 0;
	}

	hdr = (struct mqtthdr*) sess->sess_buf->msg_base;
	switch (hdr->mqtt_msg.qos) {
		case MQTT_QOS_ACK:
			if (pubAck(sess, mid, szTopic, mqtt_pktLen(hdr)))
				return 0;
			siz = mqtt_msgPUBACK(sess->sess_buf, mid);
			if (siz == -1) {
				EVERBOSE(5, "Error:: in msgPUBACK #%d - %s", 
						mqtt_GetErrno(), mqtt_GetError());
				return 0;
			}
			break;
		case MQTT_QOS_EXACTLY:
			if (pubExactly(sess, mid, szTopic, mqtt_pktLen(hdr)))
				return 0;
			siz = mqtt_msgPUBREC(sess->sess_buf, mid);
			if (siz == -1) {
				EVERBOSE(5, "Error:: in msgPUBREC #%d - %s", 
						mqtt_GetErrno(), mqtt_GetError());
				return 0;
			}
			break;
		case MQTT_QOS_ONCE:
			pubOnce(sess, szTopic, mqtt_pktLen(hdr));
		default:
			return 0;
	}

	p = mkPkt(sess->sess_buf->msg_base, siz);
	memset(sess->sess_buf->msg_base, 0, sess->sess_buf->msg_len);
	schedWrite(root, sendPacket, p, sess->sess_sock, NULL, 0);
	return 0;
}

int
cmdPUBREL(void *srv, int len, void *arg)
{
	struct tagSession *sess = (struct tagSession*) arg;
	int siz = 0;
	u_short mid = 0;
	ait_val_t *p = NULL;

	ETRACE();

	if (!sess)
		return -1;

	EVERBOSE(5, "Exec PUBREL session");
	mid = mqtt_readPUBREL(sess->sess_buf);
	if (mid == (u_short) -1) {
		EVERBOSE(5, "Error:: in readPUBREL #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		return 0;
	}

	/* delete not retain message */
	call.DeletePUB_topic(&cfg, pub, sess->sess_cid, mid, "%", sess->sess_user, 
			sess->sess_addr, 0);

	siz = mqtt_msgPUBCOMP(sess->sess_buf, mid);
	if (siz == -1) {
		EVERBOSE(5, "Error:: in msgPUBCOMP #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		return 0;
	}

	p = mkPkt(sess->sess_buf->msg_base, siz);
	memset(sess->sess_buf->msg_base, 0, sess->sess_buf->msg_len);
	schedWrite(root, sendPacket, p, sess->sess_sock, NULL, 0);
	return 0;
}

int
cmdSUBSCRIBE(void *srv, int len, void *arg)
{
	struct tagSession *sess = (struct tagSession*) arg;
	mqtt_subscr_t *subs = NULL;
	int siz = 0;
	u_short mid = 0;
	register int i;
	struct tagStore *store;
	char buf[BUFSIZ];
	void *ptr;
	ait_val_t *p = NULL;

	ETRACE();

	if (!sess)
		return -1;

	EVERBOSE(5, "Exec SUBSCRIBE session");
	siz = mqtt_readSUBSCRIBE(sess->sess_buf, &mid, &subs);
	if (siz == -1) {
		EVERBOSE(5, "Error:: in readSUBSCRIBE #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		return 0;
	}

	/* add to db */
	for (i = 0; i < siz; i++) {
		store = e_malloc(sizeof(struct tagStore));
		if (!store) {
			ELIBERR(elwix);
			continue;
		} else {
			store->st_msgid = mid;
			mqtt_subCopy(&store->st_subscr, &subs[i]);
			subs[i].sub_ret = MQTT_QOS_DENY;
		}

		/* add to cache */
		SLIST_INSERT_HEAD(&sess->sess_subscr, store, st_node);

		/* convert topic to regexp */
		if (mqtt_expandTopic(subs[i].sub_topic.msg_base, buf, sizeof buf, 1, 1) == -1) {
			EVERBOSE(5, "Error:: in regexp #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		} else {
			ptr = realloc(store->st_subscr.sub_topic.msg_base, strlen(buf) + 1);
			if (!ptr) {
				ESYSERR(0);
				continue;
			} else {
				store->st_subscr.sub_topic.msg_base = ptr;
				store->st_subscr.sub_topic.msg_len = strlen(buf) + 1;
				memcpy(store->st_subscr.sub_topic.msg_base, buf, 
						store->st_subscr.sub_topic.msg_len);
			}

			/* store to db */
			call.WritePUB_subscribe(&cfg, pub, sess->sess_cid, mid, buf, 
					sess->sess_user, sess->sess_addr, store->st_subscr.sub_ret);
			/* subscribe pass */
			subs[i].sub_ret = MQTT_QOS_PASS;

			call.LOG(logg, "Added [%s] SUBSCRIBE '%s'(%d) QoS=%d from %s\n", sess->sess_cid, 
					store->st_subscr.sub_topic.msg_base, 
					store->st_subscr.sub_topic.msg_len, 
					store->st_subscr.sub_ret, sess->sess_addr);
		}
	}

	/* send acknowledge */
	siz = mqtt_msgSUBACK(sess->sess_buf, subs, mid);
	if (siz == -1) {
		EVERBOSE(5, "Error:: in msgSUBACK #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		goto end;
	} else {
		p = mkPkt(sess->sess_buf->msg_base, siz);
		memset(sess->sess_buf->msg_base, 0, sess->sess_buf->msg_len);
	}

	schedWrite(root, sendPacket, p, sess->sess_sock, NULL, 0);
end:
	mqtt_subFree(&subs);
	return 0;
}

int
cmdUNSUBSCRIBE(void *srv, int len, void *arg)
{
	struct tagSession *sess = (struct tagSession*) arg;
	mqtt_subscr_t *subs = NULL;
	int siz = 0;
	u_short mid = 0;
	register int i;
	struct tagStore *store, *tmp;
	ait_val_t *p = NULL;

	ETRACE();

	if (!sess)
		return -1;

	EVERBOSE(5, "Exec UNSUBSCRIBE session");
	siz = mqtt_readUNSUBSCRIBE(sess->sess_buf, &mid, &subs);
	if (siz == -1) {
		EVERBOSE(5, "Error:: in readUNSUBSCRIBE #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		return 0;
	}

	/* del from db */
	for (i = 0; i < siz; i++) {
		SLIST_FOREACH_SAFE(store, &sess->sess_subscr, st_node, tmp) {
			if (store->st_subscr.sub_ret == subs[i].sub_ret && 
					store->st_subscr.sub_topic.msg_base && 
					!strcmp(store->st_subscr.sub_topic.msg_base, 
						subs[i].sub_topic.msg_base)) {
				SLIST_REMOVE(&sess->sess_subscr, store, tagStore, st_node);

				if (store->st_subscr.sub_topic.msg_base)
					free(store->st_subscr.sub_topic.msg_base);
				if (store->st_subscr.sub_value.msg_base)
					free(store->st_subscr.sub_value.msg_base);
				e_free(store);
			}
		}

		call.DeletePUB_subscribe(&cfg, pub, sess->sess_cid, subs[i].sub_topic.msg_base, 
				sess->sess_user, "%");
	}

	/* send acknowledge */
	siz = mqtt_msgUNSUBACK(sess->sess_buf, mid);
	if (siz == -1) {
		EVERBOSE(5, "Error:: in msgUNSUBACK #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		goto end;
	} else {
		p = mkPkt(sess->sess_buf->msg_base, siz);
		memset(sess->sess_buf->msg_base, 0, sess->sess_buf->msg_len);
	}

	schedWrite(root, sendPacket, p, sess->sess_sock, NULL, 0);
end:
	mqtt_subFree(&subs);
	return 0;
}

int
cmdPINGREQ(void *srv, int len, void *arg)
{
	struct tagSession *sess = (struct tagSession*) arg;
	int siz = 0;
	ait_val_t *p = NULL;

	ETRACE();

	if (!sess)
		return -1;

	EVERBOSE(5, "Exec PINGREQ session");
	siz = mqtt_msgPINGRESP(sess->sess_buf);
	if (siz == -1) {
		EVERBOSE(5, "Error:: in msgPINGRESP #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		return 0;
	} else {
		p = mkPkt(sess->sess_buf->msg_base, siz);
		memset(sess->sess_buf->msg_base, 0, sess->sess_buf->msg_len);
	}

	schedWrite(root, sendPacket, p, sess->sess_sock, NULL, 0);
	return 0;
}

int
cmdCONNECT(void *srv, int len, void *arg)
{
	struct tagStore *store;
	struct tagSession *sess = (struct tagSession*) arg;

	ETRACE();

	if (!sess)
		return -1;

	EVERBOSE(5, "Exec CONNECT session");
	TAILQ_REMOVE(&Sessions, sess, sess_node);

	schedCancelby(root, taskTIMER, CRITERIA_CALL, sendRetain, NULL);

	if (sess->sess_clean) {
		if (call.FiniSessPUB)
			call.FiniSessPUB(&cfg, pub, sess->sess_cid, sess->sess_user, "%");
		if (call.DeletePUB_subscribe)
			call.DeletePUB_subscribe(&cfg, pub, sess->sess_cid, "%", sess->sess_user, "%");
		if (call.WipePUB_topic)
			call.WipePUB_topic(&cfg, pub, sess->sess_cid, sess->sess_user, -1);
	}

	while ((store = SLIST_FIRST(&sess->sess_subscr))) {
		SLIST_REMOVE_HEAD(&sess->sess_subscr, st_node);

		if (store->st_subscr.sub_topic.msg_base)
			free(store->st_subscr.sub_topic.msg_base);
		if (store->st_subscr.sub_value.msg_base)
			free(store->st_subscr.sub_value.msg_base);

		e_free(store);
	}

	if (sess->sess_will.flag)
		pubWill(sess);

	if (sess->sess_will.msg)
		free(sess->sess_will.msg);
	if (sess->sess_will.topic)
		free(sess->sess_will.topic);

	call.LOG(logg, "Session %s stopped from %s for user %s.\n", sess->sess_cid, 
			sess->sess_addr, sess->sess_user);

	return -3;	/* reconnect client */
}

int
cmdDISCONNECT(void *srv, int len, void *arg)
{
	struct tagSession *sess = (struct tagSession*) arg;

	ETRACE();

	if (!sess)
		return -1;

	EVERBOSE(5, "Exec DISCONNECT session");

	call.LOG(logg, "Session %s stopped from %s for user %s.\n", sess->sess_cid, 
			sess->sess_addr, sess->sess_user);

	return -2;	/* must terminate dispatcher */
}