#!/public/bin/perl -w

# Converts a postscript file into PDF format
# Basically it is a wrapper script calling nup and ps2pdf with the options combined
# Read the README file for parameter rules and requirements.
# Note: This script does have code to check input variables for shell security 
#       because it assumes the user already have the right to run the script.
#
# Programmed by Eric Tong. (tonge@uvic.ca)
# Copyleft 1999(c). (http://www.gnu.org/copyleft/copyleft.html)

use strict;
use Getopt::Long;

umask(0000);

my $version = "1.00";

my $help_text = "Usage:\n".
                "  ps2pdf <options>\n\n".
                "  options:\n".
                "    <-i filename> - The input postscript filename\n".
                "    <-o filename> - The output PDF filename (optional)\n".
                "    <-p number> - The number of pages shrinked to\n".
                "                  one page (must be 2,4,8,16) (optional)\n".
                "    <-s number> - The starting offset page (optional)\n".
                "    <-override yes> - It must be set to \"yes\" if you\n".
                "                      want the script to overwrite files\n".
                "    <-perm perm> - Sets the output file permission when\n".
                "                   completed (must be in octal format)\n";
  
MAIN:
{
  my ($input_filename, $output_filename, $override_option, $nup_pages, $help_option, $start_page, $pdf_permission);
  &GetOptions( "i=s" => \$input_filename,
               "o:s" => \$output_filename,
               "p:i" => \$nup_pages,
               "h:s" => \$help_option,
               "s:i" => \$start_page,
               "override:s" => \$override_option,
               "perm:s" => \$pdf_permission);

  $input_filename = $ARGV[0] if (defined($ARGV[0]));

  # Set default varibles
  $nup_pages = 1 if (!defined($nup_pages));
  $start_page = 1 if (!defined($start_page));

  # Check input for validity
  if (!check_nup_range($nup_pages))
  {
    exit_with_message("Invalid n-up page range!");
  }
  elsif (!defined($input_filename))
  {
    exit_with_message("The input file is not defined!");
  }
  elsif (!-e $input_filename)
  {
    exit_with_message("The input file ($input_filename) does not exist!");
  }
  elsif (!defined($output_filename))
  {
    if ($input_filename =~ /^(.*)\.ps/)
    {
      $output_filename = $1 . $nup_pages . ".pdf";
    }
    elsif(defined($override_option) and $override_option eq "yes")
    {
      $output_filename = $input_filename . ".pdf";
    }
    else
    { 
      exit_with_message("The intput file does not end with a .ps extension!\n".
                        "(Use -override=yes if you want to use it anyway)");
    }
  }

  if (-e $output_filename and (!defined($override_option) or $override_option ne "yes"))
  {
    exit_with_message("The output file ($output_filename) already exist already!\n".
                      "(Use -override=yes if you want to overwrite)");
  }
  else
  {
    my $intermediate_filename = $input_filename;
    my $erase_temp_file = 0;

    # N-up the file if necessary
    if ($nup_pages > 1)
    {
      print "Creating a intermediate file...\n";
      $intermediate_filename = "$$.temp";
      my $command = "nup -$nup_pages " . ($start_page > 1 ? "-s $start_page" : "") . " $input_filename > $intermediate_filename";
      exit_with_message("Unable to create the intermediate file: $!") if (system("$command"));
      $erase_temp_file = 1;
    }

    # Convert the file
    print "Converting to pdf file...\n";
    my $command = "ps2pdf $intermediate_filename $output_filename";
    exit_with_message("Unable to create the output file: $!") if (system("$command"));

    # Erase the intermediate file if necessary
    if ($erase_temp_file and -e $intermediate_filename)
    {
      print "Removing intermediate file...\n";
      unlink($intermediate_filename) or exit_with_message("Unable to remove $intermediate_filename: $!");
    }

    # Updates the file permissions
    if (defined($pdf_permission))
    {
      print "Setting PDF file permission...\n";
      chmod(oct($pdf_permission), $output_filename) or 
        exit_with_message("Unable to set permission for $output_filename: $!");
    }
  }
}

# Checks for valid range for nup
sub check_nup_range($)
{
  return ( $_[0] == 1 or $_[0] == 2 or $_[0] == 4 or $_[0] == 8 or $_[0] == 16 );
}

# Personally I don't like dying, do you?
sub exit_with_message($)
{
  print "Postscript to PDF converter $version\n\n".
        "Error: $_[0]\n\n$help_text";
  exit 1;
}