#!/usr/bin/perl -wT
# population.pl

use strict;
use Untaint;
use LWP::UserAgent;

my $counter = untaint(qr(.*\.dat$), $ARGV[0]);
my  $ua = new LWP::UserAgent;

$ua->agent("GetCount/0.1");
my $req = new HTTP::Request GET => 'http://www.census.gov/cgi-bin/ipc/popclockw';
$req->header(Accept => "text/html");
my $res = $ua->request($req);

if ($res->is_success) {
    my $html = $res->content;
    (my $num = $html) =~ s!^.*<h1>(.*?)</h1>.*$!$1!si;

    open(LOG, $counter) || die "Can't read counter. $!";

    my $log = <LOG>;
    close LOG;

    ($num = $num) =~ s!,!!g;
    $num = $num-$log;

    1 while $num =~ s!^(\d+)(\d{3})!$1,$2!;

    print $num;
} else {
      print "[trouble calculating]";
}