/*************************************************************************
* (C) 2011 AITNET ltd - Sofia/Bulgaria - <misho@aitbg.com>
*  by Michael Pounov <misho@openbsd-bg.org>
*
* $Author: misho $
* $Id: daemon.c,v 1.6 2017/10/08 22:49:24 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 "rtlm.h"
#include "mqttd.h"
#include "mqttd_calls.h"
#include "utils.h"


static inline struct tagSession *
initSession(int sock, ait_val_t * __restrict v)
{
	struct tagSession *sess = NULL;
	const char *str;

	ETRACE();

	if (!v)
		return NULL;

	sess = e_malloc(sizeof(struct tagSession));
	if (!sess) {
		ELIBERR(elwix);
		return NULL;
	} else
		memset(sess, 0, sizeof(struct tagSession));

	SLIST_INIT(&sess->sess_subscr);

	str = cfg_getAttribute(&cfg, "mqttd", "retry");
	if (!str)
		sess->sess_retry = DEFAULT_RETRY;
	else
		sess->sess_retry = strtol(str, NULL, 0);

	sess->sess_buf = mqtt_msgAlloc(USHRT_MAX);
	if (!sess->sess_buf) {
		ELIBERR(mqtt);
		e_free(sess);
		return NULL;
	}

	/* init server actor */
	sess->sess_srv = mqtt_srv_cliInit(sock, sess->sess_buf, sess->sess_ka, 1);
	if (!sess->sess_srv) {
		EVERBOSE(3, "Error:: in srv_Init #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		mqtt_msgFree(&sess->sess_buf, 42);
		e_free(sess);
		return NULL;
	} else {
		mqtt_srv_setCmd(sess->sess_srv, MQTT_TYPE_CONNECT, cmdCONNECT);
		mqtt_srv_setCmd(sess->sess_srv, MQTT_TYPE_PUBLISH, cmdPUBLISH);
		mqtt_srv_setCmd(sess->sess_srv, MQTT_TYPE_PUBREL, cmdPUBREL);
		mqtt_srv_setCmd(sess->sess_srv, MQTT_TYPE_SUBSCRIBE, cmdSUBSCRIBE);
		mqtt_srv_setCmd(sess->sess_srv, MQTT_TYPE_UNSUBSCRIBE, cmdUNSUBSCRIBE);
		mqtt_srv_setCmd(sess->sess_srv, MQTT_TYPE_PINGREQ, cmdPINGREQ);
		mqtt_srv_setCmd(sess->sess_srv, MQTT_TYPE_DISCONNECT, cmdDISCONNECT);
	}

	sess->sess_sock = sock;
	strlcpy(sess->sess_addr, (char*) AIT_GET_STR(v), sizeof sess->sess_addr);
	return sess;
}

static void
finiSession(struct tagSession *sess)
{
	struct tagStore *store;

	ETRACE();

	if (!sess)
		return;

	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)	/* only dynamic messages */
			call.WipePUB_topic(&cfg, pub, sess->sess_cid, sess->sess_user, 0);
	}

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

	if (sess->sess_sock > STDERR_FILENO)
		srv_Close(sess->sess_sock);

	mqtt_srv_cliFini(&sess->sess_srv);
	mqtt_msgFree(&sess->sess_buf, 42);

	e_free(sess);
}

static void *
leaveClient(sched_task_t *task)
{
	struct tagSession *sess;
	int ret;

	ETRACE();

	assert(task);

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

	TAILQ_REMOVE(&Sessions, sess, sess_node);

	ret = mqtt_msgDISCONNECT(sess->sess_buf);
	send(TASK_FD(task), sess->sess_buf->msg_base, ret, MSG_NOSIGNAL);

	EVERBOSE(1, "Close socket=%ld", (long) TASK_FD(task));
	call.LOG(logg, "Session %s stopped from %s for user %s.\n", sess->sess_cid, 
			sess->sess_addr, sess->sess_user);

	finiSession(sess);
	return NULL;
}

static void *
dispatchSession(sched_task_t *task)
{
	int ret, len = 0;
	struct tagSession *sess;

	ETRACE();

	assert(task);

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

	/* receive & decode packet */
	if ((ret = recv(TASK_FD(task), sess->sess_buf->msg_base, sess->sess_buf->msg_len, 0)) == -1) {
		EVERBOSE(3, "Error:: recv(%d) #%d - %s", sess->sess_sock, errno, strerror(errno));
		TAILQ_REMOVE(&Sessions, sess, sess_node);
		finiSession(sess);
		return NULL;
	} else if (!ret) {
		EVERBOSE(4, "Session %s EOF received.", sess->sess_cid);
		TAILQ_REMOVE(&Sessions, sess, sess_node);
		finiSession(sess);
		return NULL;
	}

	do {
		/* dispatch message type */
		if ((len = mqtt_srv_cliDispatch(sess->sess_srv, ret, sess)) < 0) {
			if (len == -1) {
				ELIBERR(mqtt);
				finiSession(sess);
			} else if (len == -2) {
				TAILQ_REMOVE(&Sessions, sess, sess_node);
				finiSession(sess);
			} else if (len == -3)
				schedEvent(root, startSession, NULL, (u_long) TASK_FD(task), sess, ret);
		} else
			ret -= len;
	} while (len > 0 && ret > 0);

	if (len >= 0 && !schedRead(root, dispatchSession, TASK_ARG(task), TASK_FD(task), NULL, 0)) {
		ELIBERR(sched);
		TAILQ_REMOVE(&Sessions, sess, sess_node);
		finiSession(sess);
	}
	return NULL;
}

static int
loadSubscribes(struct tagSession * __restrict sess, mqtt_subscr_t * __restrict subs)
{
	register int i;
	struct tagStore *store;

	if (!subs)
		return -1;

	for (i = 0; subs[i].sub_topic.msg_base; i++) {
		store = e_malloc(sizeof(struct tagStore));
		if (!store) {
			ELIBERR(elwix);
			continue;
		} else {
			store->st_msgid = 0;
			mqtt_subCopy(&store->st_subscr, &subs[i]);
		}

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

	return 0;
}

void *
startSession(sched_task_t *task)
{
	u_char basebuf[USHRT_MAX];
	mqtt_msg_t buf = { basebuf, sizeof basebuf };
	mqtthdr_connflgs_t flg;
	mqtthdr_connack_t cack;
	ait_val_t *v;
	struct tagSession *s, *sess = NULL;
	int ret, wlen;
	mqtt_subscr_t *subs;
	struct timespec ts = { RETAIN_TIMEOUT, 0 };
	intptr_t sock;

	ETRACE();

	assert(task);

	if (!TASK_DATA(task)) {
		v = TASK_ARG(task);
		/* flow from accept new clients */
		sess = initSession(TASK_FD(task), v);
		ait_freeVar(&v);
		if (!sess) {
			close(TASK_FD(task));
			return NULL;
		}

		/* receive & decode packet */
		if (recv(sess->sess_sock, buf.msg_base, buf.msg_len, 0) == -1) {
			EVERBOSE(3, "Error:: recv(%d) #%d - %s", sess->sess_sock, errno, strerror(errno));
			finiSession(sess);
			return NULL;
		}
	} else {
		sess = TASK_DATA(task);
		assert(sess);

		buf.msg_len = TASK_DATLEN(task) > sizeof basebuf ? sizeof basebuf : TASK_DATLEN(task);
		memcpy(buf.msg_base, sess->sess_buf->msg_base, buf.msg_len);
	}

	cack = mqtt_readCONNECT(&buf, &sess->sess_ka, sess->sess_cid, sizeof sess->sess_cid, 
			sess->sess_user, sizeof sess->sess_user, sess->sess_pass, sizeof sess->sess_pass, 
			&sess->sess_will.topic, &sess->sess_will.msg);
	ret = cack.retcode;
	flg.flags = cack.reserved;
	if (flg.reserved) {
		EVERBOSE(3, "Error:: in MQTT protocol #%d - %s", mqtt_GetErrno(), mqtt_GetError());
		goto end;
	} else {
		sess->sess_clean = flg.clean_sess;
		sess->sess_will.qos = flg.will_qos;
		sess->sess_will.retain = flg.will_retain;
		sess->sess_will.flag = flg.will_flg;

		sess->sess_srv->timeout = sess->sess_ka;
	}

	/* check online table for user */
	if (call.LoginACC(&cfg, acc, sess->sess_user, sess->sess_pass) < 1) {
		EVERBOSE(0, "Login:: DENIED for username %s and password %s", 
				sess->sess_user, sess->sess_pass);
		ret = MQTT_RETCODE_DENIED;
		goto end;
	} else {
		EVERBOSE(1, "Login:: ALLOWED for username %s ...", sess->sess_user);
		ret = MQTT_RETCODE_ACCEPTED;
	}

	/* db management */
	if (call.FiniSessPUB(&cfg, pub, sess->sess_cid, sess->sess_user, "%") > 0) {
		EVERBOSE(2, "Old session %s should be disconnect!", sess->sess_cid);
		TAILQ_FOREACH(s, &Sessions, sess_node)
			if (!strcmp(s->sess_cid, sess->sess_cid)) {
				/* found stale session & disconnect it! */
				sock = s->sess_sock;
				schedCancelby(root, taskMAX, CRITERIA_FD, (void*) sock, NULL);
				schedWrite(root, leaveClient, s, s->sess_sock, NULL, 0);
				break;
			}
	}
	if (call.InitSessPUB(&cfg, pub, sess->sess_cid, sess->sess_user, sess->sess_addr, 
				sess->sess_will.flag, sess->sess_will.topic, sess->sess_will.msg, 
				sess->sess_will.qos, sess->sess_will.retain) == -1) {
		EVERBOSE(0, "Session %s DENIED for username %s", sess->sess_cid, sess->sess_user);
		ret = MQTT_RETCODE_DENIED;
		goto end;
	} else {
		EVERBOSE(0, "Session %s from %s and username %s is started", 
				sess->sess_cid, sess->sess_addr, sess->sess_user);
		ret = MQTT_RETCODE_ACCEPTED;
	}
	/* clean/load session if requested */
	if (sess->sess_clean) {
		if (call.DeletePUB_subscribe)
			call.DeletePUB_subscribe(&cfg, pub, sess->sess_cid, "%", sess->sess_user, "%");
		if (call.WipePUB_topic)	/* delete ALL messages */
			call.WipePUB_topic(&cfg, pub, sess->sess_cid, sess->sess_user, -1);
	} else if (call.ReadPUB_subscribe) {
		/* load subscribes */
		subs = call.ReadPUB_subscribe(&cfg, pub, sess->sess_cid, "%");
		loadSubscribes(sess, subs);
		mqtt_subFree(&subs);
	}

	/* timer event for retain messages */
	if (call.ReadPUB_topic)
		schedTimer(root, sendRetain, sess, ts, NULL, 0);

	/* Start session task OK ... */
	if (!schedRead(root, dispatchSession, sess, TASK_FD(task), NULL, 0)) {
		ELIBERR(sched);
		ret = MQTT_RETCODE_DENIED;
	} else
		TAILQ_INSERT_TAIL(&Sessions, sess, sess_node);

	call.LOG(logg, "Session %s started from %s for user %s (timeout=%d) OK!\n", sess->sess_cid, 
			sess->sess_addr, sess->sess_user, sess->sess_ka);
end:	/* close client connection */
	wlen = mqtt_msgCONNACK(sess->sess_buf, ret);
	if ((wlen = send(TASK_FD(task), sess->sess_buf->msg_base, wlen, 0)) == -1) {
		EVERBOSE(3, "Error:: send(%ld) #%d - %s", (long) TASK_FD(task), errno, strerror(errno));
	} else
		EVERBOSE(5, "Sended %d bytes", wlen);

	if (ret != MQTT_RETCODE_ACCEPTED) {
		EVERBOSE(1, "Close client %s with socket=%ld", sess->sess_addr, (long) TASK_FD(task));
		finiSession(sess);
	}
	return NULL;
}

static void *
acceptClient(sched_task_t *task)
{
	int cli;
	sockaddr_t sa;
	socklen_t sslen = sizeof sa.ss;
	ait_val_t *v;
	char str[STRSIZ];

	ETRACE();

	assert(task);

	if ((cli = accept(TASK_FD(task), &sa.sa, &sslen)) == -1)
		goto end;
	else
		fcntl(cli, F_SETFL, fcntl(cli, F_GETFL) | O_NONBLOCK);

	v = ait_allocVar();
	if (!v) {
		ELIBERR(elwix);
		close(cli);
		goto end;
	} else {
		memset(str, 0, sizeof str);
		snprintf(str, sizeof str, "%s:%hu", e_n2addr(&sa, v), e_n2port(&sa));
		AIT_FREE_VAL(v);
		AIT_SET_STR(v, str);
	}
	EVERBOSE(1, "Connected client with socket=%d from %s", cli, AIT_GET_STR(v));

	if (!schedRead(root, startSession, v, cli, NULL, 0)) {
		ait_freeVar(&v);
		close(cli);
		EVERBOSE(1, "Terminated client with socket=%d", cli);
	}
end:
	if (!schedRead(root, acceptClient, NULL, TASK_FD(task), NULL, 0))
		ELIBERR(sched);
	return NULL;
}

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

int
Run(int sock)
{
	struct tagSession *sess;
	struct timespec pl = { 0, 100000000 };

	ETRACE();

	if (mqtt_srv_Listen(sock, 0, 1) == -1) {
		ELIBERR(mqtt);
		return -1;
	}

	/* state machine - accept new connections */
	if (!schedRead(root, acceptClient, NULL, sock, NULL, 0)) {
		ELIBERR(sched);
		return -1;
	}

	schedPolling(root, &pl, NULL);
	schedRun(root, &Kill);

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

	/* free all undeleted elements into lists */
	TAILQ_FOREACH(sess, &Sessions, sess_node) {
		TAILQ_REMOVE(&Sessions, sess, sess_node);

		finiSession(sess);
	}
	return 0;
}