/*
 * Copyright (c) 2003 Bernhard Walle <bernhard.walle@gmx.de>
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <gtk/gtk.h>
#include <time.h>
#include <sys/time.h>

#include <libxfce4util/i18n.h>
#include <libxfcegui4/dialogs.h>
#include <panel/plugins.h>
#include <panel/xfce.h>

#include "net.h" 


/*
 * Basic code taken from IceWM
 * (c) Marko Macek and others, GNU General Public License
 * 
 * Converted from C++ to C (using glib data types) by Bernhard Walle
 */

void get_current_netload (const gchar* device, gint64 *in, gint64 *out, gint64 *tot) 
{
    static guint64 prev_ibytes = 0, cur_ibytes = 0, offset_ibytes = 0;
    static guint64 prev_obytes = 0, cur_obytes = 0, offset_obytes = 0;
    static struct timeval prev_time;
    static gboolean first = TRUE;
    struct timeval curr_time;
    gdouble delta_t;
    gint64 ni, no;

    gchar buf[BUFSIZ];
    gchar *p;
    gint64 ipackets, opackets, ierrs, oerrs, idrop, odrop, ififo, ofifo,
           iframe, ocolls, ocarrier, icomp, ocomp, imcast;

    FILE *fp = NULL;

    if (in != NULL && out != NULL && tot != NULL)
    {
        *in = *out = *tot = 0;
    }

    if (first)
    {
        gettimeofday(&prev_time, NULL);
    }
    gettimeofday(&curr_time, NULL);
    
    delta_t = (gdouble) ((curr_time.tv_sec  - prev_time.tv_sec) * 1000000L
                             + (curr_time.tv_usec - prev_time.tv_usec)) / 1000000.0;
    

    if ( (fp = fopen("/proc/net/dev", "r")) == NULL)
    {
        return;
    }

    while ( fgets(buf, BUFSIZ, fp) != NULL ) {
        p = buf;
        while (*p == ' ') 
        {
            p++;
        }

        if (strncmp(p, device, strlen(device)) == 0 && p[strlen(device)] == ':')
        {
            p = strchr(p, ':') + 1;

            if (sscanf(p, "%llu %lld %lld %lld %lld %lld %lld %lld" " %llu %lld %lld %lld %lld %lld %lld %lld",
                       &cur_ibytes, &ipackets, &ierrs, &idrop, &ififo, &iframe, &icomp, &imcast,
                       &cur_obytes, &opackets, &oerrs, &odrop, &ofifo, &ocolls, &ocarrier, &ocomp) != 16)
            {
                ipackets = opackets = 0;
                sscanf(p, "%lld %lld %lld %lld %lld" " %lld %lld %lld %lld %lld %lld",
                       &ipackets, &ierrs, &idrop, &ififo, &iframe,
                       &opackets, &oerrs, &odrop, &ofifo, &ocolls, &ocarrier);
                // for linux<2.0 fake packets as bytes (we only need relative values anyway)
                cur_ibytes = ipackets;
                cur_obytes = opackets;
            }

            break;
        }
    }
    fclose(fp);

    cur_ibytes += offset_ibytes;
    cur_obytes += offset_obytes;

    if (cur_ibytes < prev_ibytes)
        // har, har, overflow. Use the recent prev_ibytes value as offset this time
        cur_ibytes = offset_ibytes = prev_ibytes;

    if (cur_obytes < prev_obytes)
        // har, har, overflow. Use the recent prev_obytes value as offset this time
        cur_obytes = offset_obytes = prev_obytes;



    ni = (gint64)((cur_ibytes - prev_ibytes) / delta_t);
    no = (gint64)((cur_obytes - prev_obytes) / delta_t);

    if (in != NULL && out != NULL && tot != NULL)
    {
        *in  = ni;
        *out = no;
        *tot = *in + *out;
    }

    prev_time.tv_sec = curr_time.tv_sec;
    prev_time.tv_usec = curr_time.tv_usec;

    prev_ibytes = cur_ibytes;
    prev_obytes = cur_obytes;

    if (first) 
    {
        *in = *out = *tot = 0;
        first = FALSE;
    }
}