use Fcntl;
use Term::ReadKey;

#----------------------------(  promptUser  )-----------------------------#
#                                                                         #
#  FUNCTION:	promptUser                                                #
#                                                                         #
#  PURPOSE:	Prompt the user for some type of input, and return the    #
#		input back to the calling program.                        #
#                                                                         #
#  ARGS:	$promptString - what you want to prompt the user with     #
#		$defaultValue - (optional) a default value for the prompt #
#                                                                         #
#-------------------------------------------------------------------------#

$PROMPT_NOECHO = 1;

sub promptUser {

   #-------------------------------------------------------------------#
   #  two possible input arguments - $promptString, and $defaultValue  #
   #  make the input arguments local variables.                        #
   #-------------------------------------------------------------------#

   local($promptString,$defaultValue, $flags) = @_;

   #-------------------------------------------------------------------#
   #  if there is a default value, use the first print statement; if   #
   #  no default is provided, print the second string.                 #
   #-------------------------------------------------------------------#

   if ($defaultValue) {
      print $promptString, "[", $defaultValue, "]: ";
   } else {
      print $promptString, ": ";
   }

   $| = 1;               # force a flush after our print

   if ($flags and ($flags & $PROMPT_NOECHO)) {
       ReadMode('noecho');
       $_ = ReadLine(0);
       ReadMode(0);
       print "\n";
       chomp;
   } else {
       $_ = <STDIN>;     # get the input from STDIN (presumably the keyboard)
   }


   #------------------------------------------------------------------#
   # remove the newline character from the end of the input the user  #
   # gave us.                                                         #
   #------------------------------------------------------------------#

   chomp;

   #-----------------------------------------------------------------#
   #  if we had a $default value, and the user gave us input, then   #
   #  return the input; if we had a default, and they gave us no     #
   #  no input, return the $defaultValue.                            #
   #                                                                 # 
   #  if we did not have a default value, then just return whatever  #
   #  the user gave us.  if they just hit the <enter> key,           #
   #  the calling routine will have to deal with that.               #
   #-----------------------------------------------------------------#

   if (defined($defaultValue) && "$defaultValue") {
      return $_ ? $_ : $defaultValue;    # return $_ if it has a value
   } else {
      return $_;
   }
}

$infile = $ARGV[0];
printf("infile='$infile'\n");
$infile = promptUser("PDF file to encrypt - ", $infile);
sysopen(INFILE, $infile, O_RDONLY) || die $!;
close(INFILE);

if ($infile =~ /\.pdf$/i) {
	$outfile = $` . '-x' . '.pdf';
} else {
	$outfile = $infile . '.pdf';
}
$outfile = promptUser("output file - ", $outfile);

$oldpass = promptUser("existing password - ", '', $PROMPT_NOECHO);

$pass = "foo";
$confirm = '';
while ($pass ne $confirm) {
    $pass = promptUser("new password - ", $pass, $PROMPT_NOECHO);
    $confirm = promptUser("confirm new password - ", '', $PROMPT_NOECHO);
    if ($pass ne $confirm) {
        print " no match\n";
    }
}

$ok = "";
while (1) {
$ok = promptUser("Encrypt '$infile' to '$outfile'? ", "no");
	exit if $ok eq "no" || $ok eq "n" || $ok eq "N";
	last if ($ok eq "y" || $ok eq "Y" || $ok eq "yes");
}

#	qpdf --password=xxxxxxxx --encrypt xxxxxxxx xxxxxxxx 128 --use-aes=y -- \
#		input.pdf output.pdf

if (1) {
	# this requires a known path
	$qpdf='/usr/local/bin/qpdf/qpdf'; ## edit the path as needed
	@args = ($qpdf);
	if (length($oldpass) > 0) {
		push @args, "--password=$oldpass";
	}
	push @args, '--encrypt', $pass, $pass;
	push @args, qw/128 --use-aes=y --/  ;
	push @args, $infile, $outfile;
} else {
	# let the shell figure out the path
	@args = qw,/bin/sh -c,;
	$x = 'qpdf ';
	if (length($oldpass) > 0) {
		$x .= "--password='$oldpass' ";
	}
	$x .= "--encrypt '$pass' '$pass' ";
	$x .= '128 --use-aes=y -- '  ;
	$x .= "'$infile' '$outfile' ";
	push @args, $x;
}


$ok = "";
while (1) {
$ok = promptUser("Show the command w/ passwords? ", "no");
	last if $ok eq "no" || $ok eq "n" || $ok eq "N";
	if ($ok eq "y" || $ok eq "Y" || $ok eq "yes") {
        print join ' ',@args,"\n";
        last;
    }
}

$ok = "";
$ok = promptUser("Press Enter to proceed - ", "");

#exit 0;
system(@args);