/*
Copyright (c) 2020-2021 Roger Light <roger@atchoo.org>

All rights reserved. This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
and Eclipse Distribution License v1.0 which accompany this distribution.

The Eclipse Public License is available at
   https://www.eclipse.org/legal/epl-2.0/
and the Eclipse Distribution License is available at
  http://www.eclipse.org/org/documents/edl-v10.php.

SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause

Contributors:
   Roger Light - initial implementation and documentation.
*/

/*
 * Add an MQTT v5 user-property with key "timestamp" and value of timestamp in ISO-8601 format to all messages.
 *
 * Compile with:
 *   gcc -I<path to mosquitto-repo/include> -fPIC -shared mosquitto_timestamp.c -o mosquitto_timestamp.so
 *
 * Use in config with:
 *
 *   plugin /path/to/mosquitto_timestamp.so
 *
 * Note that this only works on Mosquitto 2.0 or later.
 */
#include "config.h"

#include <stdio.h>
#include <time.h>

#include "mosquitto_broker.h"
#include "mosquitto_plugin.h"
#include "mosquitto.h"
#include "mqtt_protocol.h"

#define PLUGIN_NAME "message-timestamp"
#define PLUGIN_VERSION "1.0"

MOSQUITTO_PLUGIN_DECLARE_VERSION(5);

static mosquitto_plugin_id_t *mosq_pid = NULL;

static int callback_message_in(int event, void *event_data, void *userdata)
{
	struct mosquitto_evt_message *ed = event_data;
	struct timespec ts;
	struct tm *ti;
	char time_buf[25];

	UNUSED(event);
	UNUSED(userdata);

	clock_gettime(CLOCK_REALTIME, &ts);
	ti = gmtime(&ts.tv_sec);
	strftime(time_buf, sizeof(time_buf), "%Y-%m-%dT%H:%M:%SZ", ti);

	return mosquitto_property_add_string_pair(&ed->properties, MQTT_PROP_USER_PROPERTY, "timestamp", time_buf);
}

int mosquitto_plugin_init(mosquitto_plugin_id_t *identifier, void **user_data, struct mosquitto_opt *opts, int opt_count)
{
	UNUSED(user_data);
	UNUSED(opts);
	UNUSED(opt_count);

	mosq_pid = identifier;
	mosquitto_plugin_set_info(identifier, PLUGIN_NAME, PLUGIN_VERSION);
	return mosquitto_callback_register(mosq_pid, MOSQ_EVT_MESSAGE_IN, callback_message_in, NULL, NULL);
}

/* mosquitto_plugin_cleanup() is optional in 2.1 and later. Use it only if you have your own cleanup to do */
int mosquitto_plugin_cleanup(void *user_data, struct mosquitto_opt *opts, int opt_count)
{
	UNUSED(user_data);
	UNUSED(opts);
	UNUSED(opt_count);

	return MOSQ_ERR_SUCCESS;
}
