/*
Copyright (c) 2019 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 v1.0
and Eclipse Distribution License v1.0 which accompany this distribution.
 
The Eclipse Public License is available at
   http://www.eclipse.org/legal/epl-v10.html
and the Eclipse Distribution License is available at
  http://www.eclipse.org/org/documents/edl-v10.php.
 
Contributors:
   Roger Light - initial implementation and documentation.
*/

#include "config.h"

#include <math.h>
#include <stdio.h>
#include <utlist.h>

#include "mosquitto_broker_internal.h"
#include "memory_mosq.h"
#include "time_mosq.h"

static struct session_expiry_list *expiry_list = NULL;
static time_t last_check = 0;


static int session_expiry__cmp(struct session_expiry_list *i1, struct session_expiry_list *i2)
{
	return i1->context->session_expiry_interval - i2->context->session_expiry_interval;
}


int session_expiry__add(struct mosquitto_db *db, struct mosquitto *context)
{
	struct session_expiry_list *item;

	item = mosquitto__calloc(1, sizeof(struct session_expiry_list));
	if(!item) return MOSQ_ERR_NOMEM;

	item->context = context;
	item->context->session_expiry_time = time(NULL);
	if(db->config->persistent_client_expiration == 0 || 
			db->config->persistent_client_expiration < item->context->session_expiry_interval){

		item->context->session_expiry_time += item->context->session_expiry_interval;
	}else{
		item->context->session_expiry_time += db->config->persistent_client_expiration;
	}
	context->expiry_list_item = item;

	DL_INSERT_INORDER(expiry_list, item, session_expiry__cmp);

	return MOSQ_ERR_SUCCESS;
}


void session_expiry__remove(struct mosquitto *context)
{
	if(context->expiry_list_item){
		DL_DELETE(expiry_list, context->expiry_list_item);
		mosquitto__free(context->expiry_list_item);
		context->expiry_list_item = NULL;
	}
}


/* Call on broker shutdown only */
void session_expiry__remove_all(struct mosquitto_db *db)
{
	struct session_expiry_list *item, *tmp;
	struct mosquitto *context;

	DL_FOREACH_SAFE(expiry_list, item, tmp){
		context = item->context;
		session_expiry__remove(context);
		context->session_expiry_interval = 0;
		context->will_delay_interval = 0;
		context__disconnect(db, context);
	}
	
}

void session_expiry__check(struct mosquitto_db *db, time_t now)
{
	struct session_expiry_list *item, *tmp;
	struct mosquitto *context;

	if(now <= last_check) return;

	last_check = now;

	DL_FOREACH_SAFE(expiry_list, item, tmp){
		if(item->context->session_expiry_interval != UINT32_MAX
				&& item->context->session_expiry_time < now){

			context = item->context;
			session_expiry__remove(context);

			context->session_expiry_interval = 0;
			context__send_will(db, context);
			context__add_to_disused(db, context);
		}else{
			return;
		}
	}
	
}