use strict;
use warnings;
#use 5.010;

use IO::Socket;

#my $host = 'localhost';
#my $host = 'time.nist.gov';
#my $host = 'nist1-sj.ustiming.org';
my $host = 'time-nw.nist.gov';      # pester microsoft
my $port = 'daytime(13)';

my $sock = IO::Socket::INET->new(
    Proto       => 'tcp',
    PeerHost    => $host,
    PeerPort    => $port,
) or die "cannot connect: $!";

while (<$sock>) {
    s/^[[:space:]]+//;
    s/[[:space:]]+\z//s;
    next if /^$/;

    # NIST Daytime Protocol format
    # http://tf.nist.gov/service/its.htm
    # JJJJJ YR-MO-DA HH:MM:SS TT L H msADV UTC(NIST) OTM
    if ($_ =~ /^(\d+)\s+(\d{2})-(\d{2})-(\d{2})\s+(\d{2}):(\d{2}):(\d{2})\s+(\d{2})\s+(\d)\s+(\d)\s+([0-9\.]+)\s+UTC\(NIST\)\s+(.)/)
    {
        my ($mjd, $yr, $mo, $da) = ($1,$2,$3,$4);
        my ($hour, $min, $sec, $dst, $lsec) = ($5,$6,$7,$8,$9);
        my ($health, $msADV, $otm) = ($10,$11,$12);
        print "NIST: $yr-$mo-$da $hour:$min:$sec\n";
    }
    else
    {
        print "$_\n";
    }
}