/*************************************************************************
* (C) 2011 AITNET ltd - Sofia/Bulgaria - <misho@aitbg.com>
*  by Michael Pounov <misho@openbsd-bg.org>
*
* $Author: misho $
* $Id: sub.c,v 1.2 2012/06/20 15:02:24 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
	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"


/*
 * mqtt_msgSUBSCRIBE() Create SUBSCRIBE message
 *
 * @buf = Message buffer
 * @Topics = MQTT subscription topics
 * @msgID = MessageID
 * @Dup = Duplicate message
 * @QOS = QoS
 * return: -1 error or >-1 message size for send
 */
int
mqtt_msgSUBSCRIBE(mqtt_msg_t * __restrict buf, mqtt_subscr_t * __restrict Topics, 
		u_short msgID, u_char Dup, u_char QOS)
{
	int len, siz = 0;
	u_int n;
	struct mqtthdr *hdr;
	mqtthdr_var_t *topic;
	mqtt_len_t *mid;
	mqtt_subscr_t *t;
	u_char *qos;
	void *data;

	if (!buf || !Topics)
		return -1;
	if (QOS > MQTT_QOS_EXACTLY) {
		mqtt_SetErr(EINVAL, "Invalid QoS parameter");
		return -1;
	}
	if (!msgID && QOS != MQTT_QOS_ONCE) {
		mqtt_SetErr(EINVAL, "Invalid MessageID parameter must be >0");
		return -1;
	}

	/* calculate message size */
	len = sizeof(mqtt_len_t);				/* msgid */
	for (t = Topics; t && t->sub_topic.msg_base; t++)	/* subscribes & qos */
		len += sizeof(mqtt_len_t) + t->sub_topic.msg_len + 1;

	/* calculate header size */
	siz = sizeof(struct mqtthdr);				/* mqtt fixed header */
	n = mqtt_encodeLen(len);				/* message size */
	siz += mqtt_sizeLen(n) - 1;				/* length size */

	if (mqtt_msgRealloc(buf, siz + len) == -1)
		return -1;
	else {
		data = buf->msg_base;
		hdr = (struct mqtthdr *) data;
	}

	/* fixed header */
	MQTTHDR_MSGINIT(hdr);
	hdr->mqtt_msg.type = MQTT_TYPE_SUBSCRIBE;
	hdr->mqtt_msg.qos = QOS;
	hdr->mqtt_msg.dup = Dup ? 1 : 0;
	hdr->mqtt_msg.retain = 0;
	*(u_int*) hdr->mqtt_len = n;
	data += siz;

	/* variable header */
	mid = (mqtt_len_t*) data;
	mid->val = htons(msgID);
	data += sizeof(mqtt_len_t);

	/* payload with subscriptions */
	for (t = Topics; t && t->sub_topic.msg_base; t++) {
		topic = (mqtthdr_var_t*) data;
		topic->var_sb.val = htons(t->sub_topic.msg_len);
		memcpy(topic->var_data, t->sub_topic.msg_base, ntohs(topic->var_sb.val));
		data += MQTTHDR_VAR_SIZEOF(topic);
		qos = data++;
		*qos = t->sub_ret;
	}

	return siz;
}

/*
 * mqtt_msgSUBACK() Create SUBACK message
 *
 * @buf = Message buffer
 * @Topics = MQTT subscription topics
 * @msgID = MessageID
 * return: -1 error or >-1 message size for send
 */
int
mqtt_msgSUBACK(mqtt_msg_t * __restrict buf, mqtt_subscr_t * __restrict Topics, u_short msgID)
{
	int siz = 0;
	struct mqtthdr *hdr;
	mqtt_len_t *v;
	mqtt_subscr_t *t;
	u_char *qos;

	if (!buf || !Topics)
		return -1;

	if (mqtt_msgRealloc(buf, MQTTMSG_MAX) == -1)
		return -1;
	else {
		hdr = (struct mqtthdr *) (buf->msg_base + siz);
		siz += sizeof(struct mqtthdr);
		v = (mqtt_len_t*) (buf->msg_base + siz);
		siz += sizeof(mqtt_len_t);
	}

	/* MessageID */
	v->val = htons(msgID);

	/* QoS payload from subscriptions */
	for (t = Topics; t && t->sub_topic.msg_base; t++) {
		qos = (buf->msg_base + siz);
		*qos = t->sub_ret;
		siz++;
	}

	/* fixed header */
	MQTTHDR_MSGINIT(hdr);
	hdr->mqtt_msg.type = MQTT_TYPE_SUBACK;
	*hdr->mqtt_len = mqtt_encodeLen(siz - sizeof(struct mqtthdr));

	return siz;
}

/*
 * mqtt_msgUNSUBSCRIBE() Create UNSUBSCRIBE message
 *
 * @buf = Message buffer
 * @Topics = MQTT subscription topics
 * @msgID = MessageID
 * @Dup = Duplicate message
 * @QOS = QoS
 * return: -1 error or >-1 message size for send
 */
int
mqtt_msgUNSUBSCRIBE(mqtt_msg_t * __restrict buf, mqtt_subscr_t * __restrict Topics, 
		u_short msgID, u_char Dup, u_char QOS)
{
	int len, siz = 0;
	u_int n;
	struct mqtthdr *hdr;
	mqtthdr_var_t *topic;
	mqtt_len_t *mid;
	mqtt_subscr_t *t;
	void *data;

	if (!buf || !Topics)
		return -1;
	if (QOS > MQTT_QOS_EXACTLY) {
		mqtt_SetErr(EINVAL, "Invalid QoS parameter");
		return -1;
	}
	if (!msgID && QOS != MQTT_QOS_ONCE) {
		mqtt_SetErr(EINVAL, "Invalid MessageID parameter must be >0");
		return -1;
	}

	/* calculate message size */
	len = sizeof(mqtt_len_t);				/* msgid */
	for (t = Topics; t && t->sub_topic.msg_base; t++)	/* subscribes */
		len += sizeof(mqtt_len_t) + t->sub_topic.msg_len;

	/* calculate header size */
	siz = sizeof(struct mqtthdr);				/* mqtt fixed header */
	n = mqtt_encodeLen(len);				/* message size */
	siz += mqtt_sizeLen(n) - 1;				/* length size */

	if (mqtt_msgRealloc(buf, siz + len) == -1)
		return -1;
	else {
		data = buf->msg_base;
		hdr = (struct mqtthdr *) data;
	}

	/* fixed header */
	MQTTHDR_MSGINIT(hdr);
	hdr->mqtt_msg.type = MQTT_TYPE_UNSUBSCRIBE;
	hdr->mqtt_msg.qos = QOS;
	hdr->mqtt_msg.dup = Dup ? 1 : 0;
	hdr->mqtt_msg.retain = 0;
	*(u_int*) hdr->mqtt_len = n;
	data += siz;

	/* variable header */
	mid = (mqtt_len_t*) (buf->msg_base + siz);
	mid->val = htons(msgID);
	data += sizeof(mqtt_len_t);

	/* payload with subscriptions */
	for (t = Topics; t && t->sub_topic.msg_base; t++) {
		topic = (mqtthdr_var_t*) data;
		topic->var_sb.val = htons(t->sub_topic.msg_len);
		memcpy(topic->var_data, t->sub_topic.msg_base, ntohs(topic->var_sb.val));
		data += MQTTHDR_VAR_SIZEOF(topic);
	}

	return siz;
}

/*
 * mqtt_msgUNSUBACK() Create UNSUBACK message
 *
 * @buf = Message buffer
 * @msgID = MessageID
 * return: -1 error or >-1 message size for send
 */
int
mqtt_msgUNSUBACK(mqtt_msg_t * __restrict buf, u_short msgID)
{
	int siz = 0;
	struct mqtthdr *hdr;
	mqtt_len_t *v;

	if (!buf)
		return -1;

	if (mqtt_msgRealloc(buf, sizeof(struct mqtthdr) + sizeof(mqtt_len_t)) == -1)
		return -1;
	else {
		hdr = (struct mqtthdr *) (buf->msg_base + siz);
		siz += sizeof(struct mqtthdr);
		v = (mqtt_len_t*) (buf->msg_base + siz);
		siz += sizeof(mqtt_len_t);
	}

	/* fixed header */
	MQTTHDR_MSGINIT(hdr);
	hdr->mqtt_msg.type = MQTT_TYPE_UNSUBACK;
	*hdr->mqtt_len = sizeof(mqtt_len_t);

	/* MessageID */
	v->val = htons(msgID);

	return siz;
}


/* ============= decode ============ */

/*
 * mqtt_readSUBSCRIBE() Read SUBSCRIBE message
 *
 * @buf = Message buffer
 * @msgID = MessageID
 * @subscr = Subscriptions, must be free after use with mqtt_subFree()
 * return: -1 error or >-1 elements into subscr
 */
int
mqtt_readSUBSCRIBE(mqtt_msg_t * __restrict buf, u_short *msgID, mqtt_subscr_t **subscr)
{
	register int i;
	int len, ret;
	struct mqtthdr *hdr;
	mqtthdr_var_t *var;
	mqtt_subscr_t *subs;
	mqtt_len_t *v;
	caddr_t pos;

	if (!buf || !msgID || !subscr)
		return -1;

	hdr = _mqtt_readHEADER(buf, MQTT_TYPE_SUBSCRIBE, &ret, &len);
	if (!hdr)
		return -1;
	pos = buf->msg_base + ret + 1;
	v = (mqtt_len_t*) pos;

	/* MessageID */
	len -= sizeof(mqtt_len_t);
	if (len < 0) {
		mqtt_SetErr(EINVAL, "Short message length %d", len);
		return -1;
	} else {
		*msgID = ntohs(v->val);
		pos += sizeof(mqtt_len_t);
	}

	subs = mqtt_subAlloc(0);
	if (!subs)
		return -1;
	else
		*subscr = subs;

	/* Subscribes */
	for (i = 0; len > 0; i++) {
		var = (mqtthdr_var_t*) pos;
		len -= MQTTHDR_VAR_SIZEOF(var) + 1;
		if (len < 0) {
			mqtt_subFree(subscr);
			mqtt_SetErr(EINVAL, "Short message length %d", len);
			return -1;
		}
		if (!mqtt_subRealloc(&subs, i + 1)) {
			mqtt_subFree(subscr);
			return -1;
		} else
			*subscr = subs;

		memset(&subs[i], 0, sizeof subs[i]);
		subs[i].sub_topic.msg_len = ntohs(var->var_sb.val);
		subs[i].sub_topic.msg_base = malloc(subs[i].sub_topic.msg_len + 1);
		if (!subs[i].sub_topic.msg_base) {
			LOGERR;
			mqtt_subFree(subscr);
			return -1;
		} else {
			memcpy(subs[i].sub_topic.msg_base, var->var_data, subs[i].sub_topic.msg_len);
			((char*) subs[i].sub_topic.msg_base)[subs[i].sub_topic.msg_len] = 0;
		}
		pos += MQTTHDR_VAR_SIZEOF(var);

		subs[i].sub_ret = *pos;
		pos++;
	}

	return i;
}

/*
 * mqtt_readSUBACK() Read SUBACK message
 *
 * @buf = Message buffer
 * @msgID = MessageID
 * @subqos = Subscribes QoS, must be free after use with free()
 * return: -1 error or >-1 readed subscribes QoS elements
 */
int
mqtt_readSUBACK(mqtt_msg_t * __restrict buf, u_short *msgID, u_char **subqos)
{
	int len, ret;
	struct mqtthdr *hdr;
	mqtt_len_t *v;
	caddr_t pos;

	if (!buf || !msgID || !subqos)
		return -1;

	hdr = _mqtt_readHEADER(buf, MQTT_TYPE_SUBACK, &ret, &len);
	if (!hdr)
		return -1;
	pos = buf->msg_base + ret + 1;
	v = (mqtt_len_t*) pos;

	/* MessageID */
	len -= sizeof(mqtt_len_t);
	if (len < 0) {
		mqtt_SetErr(EINVAL, "Short message length %d", len);
		return -1;
	} else {
		*msgID = ntohs(v->val);
		pos += sizeof(mqtt_len_t);
	}

	/* Subscribes */
	*subqos = malloc(len);
	if (!*subqos) {
		LOGERR;
		return -1;
	} else
		memcpy(*subqos, pos, len);

	return len;
}

/*
 * mqtt_readUNSUBSCRIBE() Read UNSUBSCRIBE message
 *
 * @buf = Message buffer
 * @msgID = MessageID
 * @subscr = Subscriptions, must be free after use with mqtt_subFree()
 * return: -1 error or >-1 elements into subscr
 */
int
mqtt_readUNSUBSCRIBE(mqtt_msg_t * __restrict buf, u_short *msgID, mqtt_subscr_t **subscr)
{
	register int i;
	int len, ret;
	struct mqtthdr *hdr;
	mqtthdr_var_t *var;
	mqtt_subscr_t *subs;
	mqtt_len_t *v;
	caddr_t pos;

	if (!buf || !msgID || !subscr)
		return -1;

	hdr = _mqtt_readHEADER(buf, MQTT_TYPE_UNSUBSCRIBE, &ret, &len);
	if (!hdr)
		return -1;
	pos = buf->msg_base + ret + 1;
	v = (mqtt_len_t*) pos;

	/* MessageID */
	len -= sizeof(mqtt_len_t);
	if (len < 0) {
		mqtt_SetErr(EINVAL, "Short message length %d", len);
		return -1;
	} else {
		*msgID = ntohs(v->val);
		pos += sizeof(mqtt_len_t);
	}

	subs = mqtt_subAlloc(0);
	if (!subs)
		return -1;
	else
		*subscr = subs;

	/* Subscribes */
	for (i = 0; len > 0; i++) {
		var = (mqtthdr_var_t*) pos;
		len -= MQTTHDR_VAR_SIZEOF(var);
		if (len < 0) {
			mqtt_subFree(subscr);
			mqtt_SetErr(EINVAL, "Short message length %d", len);
			return -1;
		}
		if (!mqtt_subRealloc(&subs, i + 1)) {
			mqtt_subFree(subscr);
			return -1;
		} else
			*subscr = subs;

		memset(&subs[i], 0, sizeof subs[i]);
		subs[i].sub_topic.msg_len = ntohs(var->var_sb.val);
		subs[i].sub_topic.msg_base = malloc(subs[i].sub_topic.msg_len + 1);
		if (!subs[i].sub_topic.msg_base) {
			LOGERR;
			mqtt_subFree(subscr);
			return -1;
		} else {
			memcpy(subs[i].sub_topic.msg_base, var->var_data, subs[i].sub_topic.msg_len);
			((char*) subs[i].sub_topic.msg_base)[subs[i].sub_topic.msg_len] = 0;
		}
		pos += MQTTHDR_VAR_SIZEOF(var);
	}

	return i;
}

/*
 * mqtt_readUNSUBACK() Read UNSUBACK message
 *
 * @buf = Message buffer
 * return: -1 error or MessageID
 */
u_short
mqtt_readUNSUBACK(mqtt_msg_t * __restrict buf)
{
	int len, ret;
	struct mqtthdr *hdr;
	mqtt_len_t *v;
	caddr_t pos;

	hdr = _mqtt_readHEADER(buf, MQTT_TYPE_UNSUBACK, &ret, &len);
	if (!hdr)
		return (u_short) -1;
	if (len < sizeof(mqtt_len_t)) {
		mqtt_SetErr(EINVAL, "Short message length %d", len);
		return (u_short) -1;
	} else {
		pos = buf->msg_base + ret + 1;
		v = (mqtt_len_t*) pos;
	}

	return ntohs(v->val);
}