#!/usr/bin/perl

#  The following was written by John R Saathoff
#  www.jrsaathoff.com

#  To the extent possible under law, John Saathoff  has waived all
#  copyright and related or neighboring rights to this work.

use MIME::Base64;
use Digest::MD5 qw(md5 md5_hex md5_base64);
use Getopt::Long;

my ($opt_d, $opt_p, $opt_h, $opt_l) = (0,0,0,10);

$result = GetOptions ("d|domain=s"      => \$opt_d,     # string
                      "p|password=s"    => \$opt_p,     # string
                      "h|?|help"        => \$opt_h,     # boolean
                      "l|length=i"      => \$opt_l);    # integer

if (! $result) { die "\nIncorrect input, run -h for help\n"; }
if ($opt_h)    { usage(); }

# If not provided on the command line prompt for domain and master password

if (! $opt_p) {
  print "master password = ";

  # Don't display the password on the terminal
  # but probably only works in linux
  system("stty -echo");
  chop($opt_p = <>);
  print "\n";
  system("stty echo");
}
if (! $opt_d) {
  print "domain          = ";
  chomp($opt_d = <>);
}

# MD5 the starting string until we get a valid password or at least 10 times

$password  = "";
$md5string = $opt_p.':'.$opt_d;

$i = 0;
while (($i < 10) || (! validpassword())) {
  $md5string = md5_base64($md5string);

  # The following three lines are simply to make the Perl MD5
  # return the same result as the javascript MD5 funciton
  $md5string = $md5string.'AA';
  $md5string =~ s/\+/9/g;
  $md5string =~ s/\//8/g;

  $password = substr($md5string, 0, $opt_l);
  $i++;
}

print "site password   = $password\n";

###########  validpassword  ###########################

# Returns true if global variable $password is valid

sub validpassword {
  $valid = 1;

  # Always contain at least one uppercase letter of the alphabet
  # Always contain at least one numeral
  # Always start with a lowercase letter of the alphabet
  $valid = $valid && ($password =~ m/[A-Z]/);
  $valid = $valid && ($password =~ m/[0-9]/);
  $valid = $valid && ($password =~ m/^[a-z]/);

  return $valid;
}

###########  USAGE  ###########################

# Print help and exit program
sub usage {
  print "\n";
  print "-d, --domain       the site domain\n";
  print "-p, --password     your master password\n";
  print "-l, --length       the length of the generated password (default is 10)\n";
  print "-h, -?, --help     prints help and exits\n";

  die "\n";
}