use strict;
use Getopt::Long;
use Net::Ping;
use Time::HiRes qw( gettimeofday tv_interval );

#vars
my %args;
my @hosts;

#option defaults
my $timeout  = 3;
my $yawn     = 2;
my $infile   = 'pinger_time_hostlist.txt';
my $outfile  = 'pinger_time_results.txt';
my $help;

my $ok = GetOptions (
   'wait=i'        => \$timeout,
   'sleep=i'       => \$yawn,
   'inputfile=s'   => \$infile,
   'outputfile=s'  => \$outfile,
   'help'          => \$help
);
usage() if ! $ok || $help;

#go!
open OUT, ">>$outfile" or die "Can't open $outfile for writing: $!";
select OUT;
$|=1;
open(STDERR, ">&OUT");

open IN, "$infile" or die "Can't open $infile: $!";
while (<IN>) {
   chomp;
   s/\s*#.*//;
   push @hosts, $_ unless /^$/;
}
close IN;

my $p = Net::Ping->new("icmp",$timeout,32);

while (1) {
   foreach my $host (@hosts) {
      my @times;
      for (1..4) {
         my $t0 = [gettimeofday];
         my $alive = $p->ping($host);
         my $t1 = tv_interval ($t0, [gettimeofday]);
         push @times, 
            $alive ?             # was ping successful?
            int($t1 * 1000) :    # if so, record interval
            $timeout * 1000;     # if not, record timeout val
      }
      my ($sec, $min, $hr, $day, $month, $year) = (localtime)[0..5];
      my $timestamp = sprintf("%04d-%02d-%02d,%02d:%02d:%02d",
         $year + 1900, $month + 1, $day, $hr, $min, $sec);
      print "$timestamp,$host,", join ( ',', @times ), "\n";
   }
   sleep $yawn;
}
$p->close();

sub usage {
   (my $msg = <<"   MSG") =~ s/^\s{3}//mg;
   
   Usage:  $0 [-w timeout] [-s sleep] [-i inputfile]
                     [-o outputfile] [-h]
   
   Options:
       -w timeout     Timeout in seconds to wait for each reply
                        (default $timeout seconds)
       -s sleep       Sleep time in seconds to pause after pinging
                        through hostlist (default $yawn seconds)
       -i inputfile   File containing list of hosts to ping
                        (default $infile)
       -o outputfile  Output log file (default $outfile)
       -h             Displays this help
   MSG
   die $msg;
}