#!/usr/bin/perl -w

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
# 

use POSIX;
use RRDs;
use strict;

#
# Basic setup
#

my $iface               = 'wlan0';   # wireless interface
my $step                = 10;       # sec
my $next1_factor        = 60;       # $step * $next1_factor = 10*60  = 600 sec  = 10 min
my $next2_factor        = 360;      # $step * $next2_factor = 10*360 = 3600 sec = 1 hour
my $update_graph_period = 10;       # How often will be graph updated (1..1000)

#
# Setup files locations
# 

my $wifi_proc_file='/proc/net/wireless';
my $dev_proc_file='/proc/net/dev';
my $rrd='./istatd.rrd';
my $signal_image='signal.png';
my $transfer_image='transfer.png';
my $pid_file='./istatd.pid';

#
# End setup
#
############################################################

my $start=time;
my $syncrorun;
my $switcher=$ARGV[0];
if (!($switcher)) { $switcher='undef'; }

if ($switcher eq 'start') {
    &start();
}
elsif ($switcher eq 'stop') {
    &stop();
}
elsif ($switcher eq 'graph') {
    &update_graph();
}
elsif ($switcher eq 'install') {
    &install();
}
else {
    print qq(Usage: ./istatd.pl option
    option: start   - Starting daemon
            stop    - Stopping daemon
            graph   - Get the latest graph
            install - Init database
    );
}

###############################################################
sub install {
    my $sec_in_the_day=86400;
    my $sec_in_the_week=$sec_in_the_day*7;
    my $sec_in_the_month=$sec_in_the_day*31;
    my $minvalue=0;
    my $maxvalue=255;
    my $xfiles_factor=0.5;
    my $max_interval=$step/$xfiles_factor;
    my $number_steps_day=floor($sec_in_the_day/$step);
    my $number_steps_week=floor($sec_in_the_week/($step*$next1_factor));
    my $number_steps_month=floor($sec_in_the_month/($step*$next2_factor));
    RRDs::create ($rrd, "--start",$start-1, "--step",$step,
          "DS:link:GAUGE:$max_interval:$minvalue:$maxvalue",
          "DS:level:GAUGE:$max_interval:$minvalue:$maxvalue",
          "DS:noise:GAUGE:$max_interval:$minvalue:$maxvalue",
          "DS:in:COUNTER:$max_interval:0:U",
          "DS:out:COUNTER:$max_interval:0:U",
          "RRA:AVERAGE:$xfiles_factor:1:$number_steps_day",
          "RRA:AVERAGE:$xfiles_factor:$next1_factor:$number_steps_week",
          "RRA:AVERAGE:$xfiles_factor:$next2_factor:$number_steps_month");
    my $ERROR = RRDs::error;
    die "$0: unable to create `$rrd': $ERROR\n" if $ERROR;
    print "Done.\n";
}

###############################################################
sub start {
    my $pid=fork;
    exit if $pid;
    die "Could't fork: $!" unless defined($pid);
    POSIX::setsid() or die "Can't start a new session: $!";
    $SIG{INT}=$SIG{TERM}=$SIG{HUP}=\&syncro_handler;
    $syncrorun=1;
    my $pid_id=$$;
    open(FILE, ">>$pid_file") || die "Cant write to $pid_file file: $!";
    print FILE $pid_id;
    close(FILE);
    my $counter=0;
    while ($syncrorun) {
        $counter++;
        if (!( -e $pid_file)) { $syncrorun=0; }
        &get_data();
        if ($counter == $update_graph_period) {
            &update_graph();
            $counter=0;
        }
        sleep($step);
    }
}

##############################################################
sub stop {
    my $pid=`cat $pid_file`;
    `kill $pid`;
}

##############################################################
sub update_graph {
    RRDs::graph "$signal_image",
      "--title", " $iface signal statistics",
      "--start", "now-12h",
      "--end", "now",
      "--lower-limit=0",
      "--interlace",
      "--imgformat","PNG",
      "--width=450",
      "DEF:link=$rrd:link:AVERAGE",
#      "DEF:level=$rrd:level:AVERAGE",
#      "DEF:noise=$rrd:noise:AVERAGE",
      "AREA:link#00b6e4:link",
#      "LINE1:level#0022e9:level",
#      "LINE1:noise#cc0000:noise"
    ;
    print "ERROR ".RRDs::error."\n" if (RRDs::error);

    RRDs::graph "$transfer_image",
      "--title", " $iface transfer statistics",
      "--start", "now-12h",
      "--end", "now",
      "--lower-limit=0",
      "--interlace",
      "--imgformat","PNG",
      "--width=450",
      "DEF:in=$rrd:in:AVERAGE",
      "DEF:out=$rrd:out:AVERAGE",
      "AREA:in#00b6e4:in",
      "LINE1:out#0022e9:out",
    ;
    print "ERROR ".RRDs::error."\n" if (RRDs::error);
}

###############################################################
sub get_data {
	my ($link,$level,$noise,$in,$out) = ("U","U","U","U","U");

	open(FILE, "$wifi_proc_file") || die "Cant open $wifi_proc_file file: $!";
	while (my $line=<FILE>) {
		($link,$level,$noise) = ($1,$2,$3) if ($line=~/\s*?$iface\:\s+?\d+?\s+?(\d+)\.*?\d*?\s+?(\d+)\.*?\d*?\s+?(\d+)\.*?\d*?.*/);
	}
	close(FILE);

	open(FILE, "$dev_proc_file") || die "Cant open $dev_proc_file file: $!";
	while (my $line=<FILE>) {
		if ($line=~/\s*?$iface\:\s*?(\d+.*)$/) {
			my @v = split(/\s+/,$1,16);
			($in,$out) = ($v[0],$v[8]);
		}
	}
	close(FILE);
	RRDs::update ("$rrd", "--template", "link:level:noise:in:out", "N:$link:$level:$noise:$in:$out");
	print "ERROR ".RRDs::error."\n" if (RRDs::error);
}

###############################################################
sub syncro_handler {
    unlink($pid_file) || die "Cant unlink $pid_file file: $!";
    $syncrorun=0;
}