use strict;
use warnings;
use Getopt::Long qw(:config no_ignore_case); #bundling
use Pod::Usage;

use threads;
use Net::Ping;

########
my %opts;
my ($opt_help, $opt_man);

GetOptions(
  'start=i'   => \$opts{'start'},
  'Stop=i'    => \$opts{'stop'},
  'Threads=i' => \$opts{'threads'},
  'help!'     => \$opt_help,
  'man!'      => \$opt_man,
) or pod2usage(-verbose => 0);

if (!@ARGV) {
    pod2usage(-verbose => 0, -message => "$0: network required\n")
}
########

if (!defined($opts{'start'}))   { $opts{'start'}    = 1   }
if (!defined($opts{'stop'}))    { $opts{'stop'}     = 254 }
if (!defined($opts{'threads'})) { $opts{'threads'}  = 5   }

if ($opts{'start'} > $opts{'stop'}) {
    print "$0: start is greater than stop\n";
    exit 1
}

my @th;
my $count = 0;
for (@ARGV) {

    if ($_ !~ /^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.\d{1,3}$/) {
        print "$0: $_ is not valid network, skipping ...\n";
        next
    }

    $opts{'net'} = $1 . "." . $2 . "." . $3 . ".";
    print "Pinging network:  $opts{'net'}0\n";
    $th[$count++] = threads->create(\&THPING, \%opts)
}

for (@th) {
    $_->join
}

sub THPING {

    my ($args) = @_;

    my @th;
    my $count = 0;

    for ($args->{'start'}..$args->{'stop'}) {
        print "  Pinging host:  $args->{'net'}$_\n";
        $th[$count++] = threads->create(\&PINGIT, $args->{'net'} . $_)
    }

    for (@th) {
        $_->join
    }

    return 0
}

sub PINGIT {

    my ($addr) = @_;

    my $p = Net::Ping->new();

    if ($p->ping($addr)) {
        print "$addr is alive.\n"
    } else {
        print "$addr is DEAD.\n"
    } 

    $p->close();

    return 0
}