#!/usr/bin/perl
use strict;
use warnings;
use File::Copy qw(cp);

my @files = @ARGV;

exit unless @files;
die "pdfcat.pdf exists\n" if -e 'pdfcat.pdf';

my $dir_prefix = "/tmp/pdfcat-$$";
my $count;
my $dir_name = $dir_prefix;

while( -e $dir_name) {
    $count++;
    $dir_name = "$dir_prefix-$count";
}

mkdir $dir_name;
foreach (@files) {
    cp $_, $dir_name;
    s|^.*/||;
}

my $tex_file = "$dir_name/pdfcat.tex";

open(TEX_FILE, ">>$tex_file") or die "can't write '$tex_file': $!";

print TEX_FILE <<'__BEGIN__';
\documentclass{article}
\usepackage{pdfpages}
\begin{document}
__BEGIN__

print TEX_FILE "\\includepdf{$_}\n" foreach (@files);

print TEX_FILE <<'__FIN__';
\end{document}
__FIN__

close TEX_FILE;

system("cd $dir_name; pdflatex $tex_file");

my $pdf_out = "$dir_name/pdfcat.pdf";

if( ! -f $pdf_out) {
  die "temp outfile '$pdf_out' not created properly\n";
}

cp($pdf_out, ".");

opendir( TMP_DIR, $dir_name) or die "can't open dir '$dir_name'\n";

while( my $file = readdir TMP_DIR) {
  next if $file =~ /^\.\.?$/;
  unlink "$dir_name/$file";
}

closedir TMP_DIR;
rmdir $dir_name;