#! /usr/bin/env perl

# gperl - add Perl part to groff files, this is the preprocessor for that

# Source file position: <groff-source>/contrib/gperl/gperl.pl
# Installed position: <prefix>/bin/gperl

# Copyright (C) 2014  Free Software Foundation, Inc.

# Written by Bernd Warken <groff-bernd.warken-72@web.de>.

my $version = '1.2.6';

# This file is part of `gperl', which is part of `groff'.

# `groff' is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 2 of the License, or
# (at your option) any later version.

# `groff' is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.

# You can find a copy of the GNU General Public License in the internet
# at <http://www.gnu.org/licenses/gpl-2.0.html>.

########################################################################

use strict;
use warnings;
#use diagnostics;

# temporary dir and files
use File::Temp qw/ tempfile tempdir /;

# needed for temporary dir
use File::Spec;

# for `copy' and `move'
use File::Copy;

# for fileparse, dirname and basename
use File::Basename;

# current working directory
use Cwd;

# $Bin is the directory where this script is located
use FindBin;


########################################################################
# system variables and exported variables
########################################################################

$\ = "\n";	# final part for print command

########################################################################
# read-only variables with double-@ construct
########################################################################

our $File_split_env_sh;
our $File_version_sh;
our $Groff_Version;

my $before_make;		# script before run of `make'
{
  my $at = '@';
  $before_make = 1 if '1.22.3' eq "${at}VERSION${at}";
}

my %at_at;
my $file_perl_test_pl;
my $groffer_libdir;

if ($before_make) {
  my $gperl_source_dir = $FindBin::Bin;
  $at_at{'BINDIR'} = $gperl_source_dir;
  $at_at{'G'} = '';
} else {
  $at_at{'BINDIR'} = '/usr/local/bin';
  $at_at{'G'} = '';
}


########################################################################
# options
########################################################################

foreach (@ARGV) {
  if ( /^(-h|--h|--he|--hel|--help)$/ ) {
    print q(Usage for the `gperl' program:);
    print 'gperl [-] [--] [filespec...] normal file name arguments';
    print 'gperl [-h|--help]        gives usage information';
    print 'gperl [-v|--version]     displays the version number';
    print q(This program is a `groff' preprocessor that handles Perl ) .
      q(parts in `roff' files.);
    exit;
  } elsif ( /^(-v|--v|--ve|--ver|--vers|--versi|--versio|--version)$/ ) {
    print q(`gperl' version ) . $version;
    exit;
  }
}


#######################################################################
# temporary file
#######################################################################

my $out_file;
{
  my $template = 'gperl_' . "$$" . '_XXXX';
  my $tmpdir;
  foreach ($ENV{'GROFF_TMPDIR'}, $ENV{'TMPDIR'}, $ENV{'TMP'}, $ENV{'TEMP'},
	   $ENV{'TEMPDIR'}, 'tmp', $ENV{'HOME'},
	   File::Spec->catfile($ENV{'HOME'}, 'tmp')) {
    if ($_ && -d $_ && -w $_) {
      eval { $tmpdir = tempdir( $template,
				CLEANUP => 1, DIR => "$_" ); };
      last if $tmpdir;
    }
  }
  $out_file = File::Spec->catfile($tmpdir, $template);
}


########################################################################
# input
########################################################################

my $perl_mode = 0;

foreach (<>) {
  chomp;
  s/\s+$//;
  my $line = $_;
  my $is_dot_Perl = $line =~ /^[.']\s*Perl(|\s+.*)$/;

  unless ( $is_dot_Perl ) {	# not a `.Perl' line
    if ( $perl_mode ) {		# is running in Perl mode
      print OUT $line;
    } else {			# normal line, not Perl-related
      print $line;
    }
    next;
  }


  ##########
  # now the line is a `.Perl' line

  my $args = $line;
  $args =~ s/\s+$//;	# remove final spaces
  $args =~ s/^[.']\s*Perl\s*//;	# omit .Perl part, leave the arguments

  my @args = split /\s+/, $args;

  ##########
  # start Perl mode
  if ( @args == 0 || @args == 1 && $args[0] eq 'start' ) {
    # For `.Perl' no args or first arg `start' means opening `Perl' mode.
    # Everything else means an ending command.
    if ( $perl_mode ) {
      # `.Perl' was started twice, ignore
      print STDERR q(`.Perl' starter was run several times);
      next;
    } else {	# new Perl start
      $perl_mode = 1;
      open OUT, '>', $out_file;
      next;
    }
  }

  ##########
  # now the line must be a Perl ending line (stop)

  unless ( $perl_mode ) {
    print STDERR 'gperl: there was a Perl ending without being in ' .
      'Perl mode:';
    print STDERR '    ' . $line;
    next;
  }

  $perl_mode = 0;	# `Perl' stop calling is correct
  close OUT;		# close the storing of `Perl' commands

  ##########
  # run this `Perl' part, later on about storage of the result
  # array stores prints with \n
  my @print_res = `perl $out_file`;

  # remove `stop' arg if exists
  shift @args if ( $args[0] eq 'stop' );

  if ( @args == 0 ) {
    # no args for saving, so @print_res doesn't matter
    next;
  }

  my @var_names = ();
  my @mode_names = ();

  my $mode = '.ds';
  for ( @args ) {
    if ( /^\.?ds$/ ) {
      $mode = '.ds';
      next;
    }
    if ( /^\.?nr$/ ) {
      $mode = '.nr';
      next;
    }
    push @mode_names, $mode;
    push @var_names, $_;
  }

  my $n_res = @print_res;
  my $n_vars = @var_names;

  if ( $n_vars < $n_res ) {
    print STDERR 'gperl: not enough variables for Perl part: ' .
      $n_vars . ' variables for ' . $n_res . ' output lines.';
  } elsif ( $n_vars > $n_res ) {
    print STDERR 'gperl: too many variablenames for Perl part: ' .
      $n_vars . ' variables for ' . $n_res . ' output lines.';
  }
  if ( $n_vars < $n_res ) {
    print STDERR 'gperl: not enough variables for Perl part: ' .
      $n_vars . ' variables for ' . $n_res . ' output lines.';
  }

  my $n_min = $n_res;
  $n_min = $n_vars if ( $n_vars < $n_res );
  exit unless ( $n_min );
  $n_min -= 1; # for starting with 0

  for my $i ( 0..$n_min ) {
    my $value = $print_res[$i];
    chomp $value;
    print $mode_names[$i] . ' ' . $var_names[$i] . ' ' . $value;
  }
}


1;
########################################################################
### Emacs settings
# Local Variables:
# mode: CPerl
# End:
