#!/usr/bin/env perl

# This script determines all files that are recursively \input by a given
# LaTeX file.
#
# This script has two modes:
#  1. Inline mode (the default):  Create a single LaTeX file for the document,
#     by inlining "\input" commands.
#     The result is appropriate to be sent to a publisher.
#       latex-process-inputs main-file.tex > onefile.tex
#     Additionally, the body of each comment is removed, to prevent revealing
#     more information than we want.  (Actually, each comment is replaced by
#     an empty comment, to prevent changes in paragraph breaks.)
#     (This could perhaps be replaced by the "expand" module of the rubber program.)
#  2. List mode: List all the files that are (transitively) "\input".
#     This can be useful for getting a list of source files in a logical order,
#     for example to be used in a Makefile or Ant buildfile.
#       latex-process-inputs --list main-file.tex
#       latex-process-inputs --makefilelist main-file.tex
#       latex-process-inputs --antlist main-file.tex

# To do:
# This script needs to be cognizant of directories/subdirectories; it does not
# properly handle files included across directories.  Given:
#   foo.tex contains \include{subdir/bar.tex}
#   subdir/bar.tex contains \include{../baz.tex}
# the "../baz.tex" will be interpreted with respect to where this script was run, not the file in which it exists.  You can reproduce the problem with:
#   cd ~/research/vakilian/2015-ICSE-TQI/paper/text
#   latex-process-inputs -list 2015-icse-tqi.tex
# The fix is challenging given the current design because the document is
# treated as one huge block of text that is searched for \input, with that
#replaced by the text of the inputted file and the process repeating until
#there are no more \input commands.  The script does not know which file a
# given \input command came from.  The solution is to rewrite the script to
# work line-by-line.  That will also do a better job of not handling \input
# and %-comments in verbatm-included files.
# Writing a test suite would help with validating this change.

my $debug = 0;
# $debug = 1;

# Process command-line arguments
my $list_mode = 0;              # boolean indicating list mode vs. inline mode
my $ant_list_mode = 0;
my $makefile_list_mode = 0;
if ((@ARGV[0] eq "-help") || (@ARGV[0] eq "--help")) {
  print "Optional arguments: -list -antlist -makefilelist\n";
  exit(0);
} elsif ((@ARGV[0] eq "-list") || (@ARGV[0] eq "--list")) {
  $list_mode = 1;
  shift @ARGV;
} elsif ((@ARGV[0] eq "-antlist") || (@ARGV[0] eq "--antlist")) {
  $list_mode = 1;
  $makefile_list_mode = 1;
  shift @ARGV;
} elsif ((@ARGV[0] eq "-makefilelist") || (@ARGV[0] eq "--makefilelist")) {
  $list_mode = 1;
  $makefile_list_mode = 1;
  shift @ARGV;
}

if (scalar(@ARGV) > 1) {
  die "Supply exactly one file on the command line (got " . scalar(@ARGV) . ": " . join(" ", @ARGV) . ")";
}
# A list of all the files that have been processed so far.
my @files = ($ARGV[0]);

# I ought to abstract this out into a (recursively-called) procedure.
my $text = "";
open(TOPLEVEL, $files[0]) or die("Can't open $files[0]");
my @toplevel_lines = <TOPLEVEL>;
close TOPLEVEL;

for my $line (@toplevel_lines) {
  # kill comments on the line
  $line =~ s/((^|[^\\])%).*?$/$1/;

  while ($line =~ s/\\(input|include|subfile|lstinputlisting|verbatiminput)(\[.*\])?\{([-a-z0-9_\.+\/]+)\}/___TOKEN___/i) {
    my $verbatim_p = ($2 eq "verbatiminput");
    my $lstinput_p = ($2 eq "lstinputlisting");
    my $file = "$3";
    if ($debug) { print STDERR "INPUT: $file\n"; }
    if (-e "$file.tex") {
      $file .= ".tex";
      open(F, "$file") or die("Can't open $file");
    } elsif (-e "$file") {
      open(F, "$file") or die("Can't open $file");
    } else {
      die("File does not exist: $file.tex or $file");
    }
    push @files, $file;
    my @lines = <F>;
    close F;
    my $replace = join('', @lines);
    if ($verbatim_p) {
      $replace = "\\begin{verbatim}\n" .
	$replace .
	"\\end{verbatim}\n";
    } elsif ($lstinput_p) {
      $replace = "\\begin{lstlisting}\n" .
	$replace .
	"\\end{lstlisting}\n";
    } else {
      # kill comments
      $replace =~ s/([^\\]%).*?$/$1/gm;
    }
    $line =~ s/___TOKEN___/$replace/;
  }
  $text .= $line;
}

# kill comments
$text =~ s/([^\\]%).*?$/$1/gm;

# Insert the bibliography.
if ((! $list_mode) && ($text =~ /\\bibliography\{.*?\}/)) {
  my $bbl_file = $files[0];
  $bbl_file =~ s/\.tex$/.bbl/;
  open(BBL, "$bbl_file") or die("Run bibtex (didn't find bbl file \"$bbl_file\")");
  my @bib = <BBL>;
  close BBL;
  my $bib = join('', @bib);
  $text =~ s/\\bibliography\{.*?\}/$bib/i;
}

if ($ant_list_mode) {
  for $file (@files) {
    print "      <arg value=\"$file\"/>\n";
  }
} elsif ($makefile_list_mode) {
  print join(" \\\n", @files), "\n";
} elsif ($list_mode) {
  for $file (@files) {
    print "$file\n";
  }
} else {
  print $text;
}