/* @(#) $Id: eventinfo_list.c,v 1.5 2007/07/20 00:19:24 dcid Exp $ */

/* Copyright (C) 2003-2007 Daniel B. Cid <dcid@ossec.net>
 * All rights reserved.
 *
 * This program is a free software; you can redistribute it
 * and/or modify it under the terms of the GNU General Public
 * License (version 3) as published by the FSF - Free Software
 * Foundation.
 *
 * License details at the LICENSE file included with OSSEC or 
 * online at: http://www.ossec.net/en/licensing.html
 */


#include "shared.h" 
#include "eventinfo.h"


EventNode *eventnode;
EventNode *lastnode;

int _memoryused = 0;
int _memorymaxsize = 0;
int _max_freq = 0;


/* Create the Event List */
void OS_CreateEventList(int maxsize)
{
    eventnode = NULL;

    _memorymaxsize = maxsize;

    _memoryused = 0;

    debug1("%s: OS_CreateEventList completed.", ARGV0);
    return;
}

/* Get the last event -- or first node */
EventNode *OS_GetLastEvent()
{
    EventNode *eventnode_pt = eventnode;

    return(eventnode_pt);    
}

/* Add an event to the list -- always to the begining */
void OS_AddEvent(Eventinfo *lf)
{
    EventNode *tmp_node = eventnode;
        
    if(tmp_node)
    {
        EventNode *new_node;
        new_node = (EventNode *)calloc(1,sizeof(EventNode));
        
        if(new_node == NULL)
        {
            ErrorExit(MEM_ERROR,ARGV0);
        }

        /* Always adding to the beginning of the list 
         * The new node will become the first node and
         * new_node->next will be the previous first node
         */
        new_node->next = tmp_node;
        new_node->prev = NULL;
        tmp_node->prev = new_node;
        
        eventnode = new_node;

        /* Adding the event to the node */
        new_node->event = lf;

        _memoryused++;
        
        /* Need to remove the last nodes */
        if(_memoryused > _memorymaxsize)
        {
            int i = 0;
            EventNode *oldlast;
            
            /* Remove at least the last 10 events 
             * or the events that will not match anymore
             * (higher than max frequency)
             */
            while((i < 10)||((lf->time - lastnode->event->time) > _max_freq))
            {
                oldlast = lastnode;
                lastnode = lastnode->prev;
                lastnode->next = NULL;

                /* Free event info */
                Free_Eventinfo(oldlast->event);
                free(oldlast);

                _memoryused--;
                i++;
            }
        }
    }
    
    else
    {
        /* Adding first node */
        eventnode = (EventNode *)calloc(1,sizeof(EventNode));
        if(eventnode == NULL)
        {
            ErrorExit(MEM_ERROR,ARGV0);
        }

        eventnode->prev = NULL;
        eventnode->next = NULL;
        eventnode->event = lf;
        
        lastnode = eventnode; 
    }

    return;
}

/* EOF */