#! /usr/bin/perl

use strict ;
use warnings ;
use Getopt::Long ;
use Pod::Usage ;

=head1 NAME

genlatex - Generate a LaTeX skeleton file from a plaintext outline.

=head1 SYNOPSIS

genlatex [OPTIONS...] [-f] FILE

=head1 OPTIONS

=over 4

=item B<FILE, -f FILE, --file=FILE>

Specify the input file to use.

=item B<-o FILE, --out=FILE>

Specify the output file.

=item B<-c CLASS, --class=CLASS>

Specify the documentclass for the LaTeX file.  Options are 'article',
'report' and 'book'.  Default is 'article'.

=item B<-i NUM, --indent=NUM>

Specify the indent used to denote a change in document level in the
input file.  Default is 4.

=item B<-m, --maketitle>

Add a title to the LaTeX file.

=item B<-t TITLE, --title=TITLE>

if -m is set, specifies the title to use for the LaTeX file.
Default is `Untitled Document'.

=item B<-a AUTHOR, --author=AUTHOR>

if -m is set, specifies the author to use for the LaTeX file.
Default is the user's name from their finger info, or
`Unknown Author'.

=item B<-d DATE, --date=DATE>

if -m is set, specifies the date to use for the LaTeX file.
Default is localtime().

=item B<-p PACKAGE, --package=PACKAGE>

Specify a LaTeX package to be used in the LaTeX file.
Multiple packages can be specified.

=item B<--secnum, --nosecnum>

Specify whether or not to use section numbers in the LaTeX file.
if --nosecnum is specified, headings will be printed in the form
`\section*{..}' instead of the default `\section{..}'.

=item B<--part, --nopart>

If the documentclass is `book', this will change the highest level
of section from `chapter' to `part', and shift all the other levels
down.  The default is --nopart.

=item B<->

Read the input from STDIN, rather than an input file.

=item B<-h, --help>

Display this help message.

=item B<--man>

Display the complete documentation for this program.

=back

=head1 DESCRIPTION

While LaTeX is a great language for composing documents, it's not always
that easy to follow.  It can be quite easy to lose one's place in the
document structure when section headers may be spaced several screens
apart.

Enter I<genlatex>.  This program will allow you to create am outline of

your document in plaintext, then generate a LaTeX skeleton based on your
outline.  Here's an example of an outline file:

    %
    % My Report
    %
    Introduction
        The Project
        The People
        The Tools
            Hardware
            Software
    Planning
        The Meetings
        The Schedule
    Implementation
        The Timeline
        The Obstacles
    Conclusion
        The Accomplishments
        The shortcomings

Note the indenting used to indicate the change in document level.
Any comments (lines beginning with %) at the beginning of the file
will show up at the beginning of the LaTeX document.  Any other comments
will show up where they appear in the outline.

Here is the LaTeX skeleton generated using the default parameters:

    %
    % My Report
    %
    
    \documentclass{article}
    
    \begin{document}
    
    \section{Introduction}
    
    \subsection{The Project}
    
    \subsection{The People}
    
    \subsection{The Tools}
    
    \subsubsection{Hardware}
    
    \subsubsection{Software}
    
    \section{Planning}
    
    \subsection{The Meetings}
    
    \subsection{The Schedule}
    
    \section{Implementation}
    
    \subsection{The Timeline}
    
    \subsection{The Obstacles}
    
    \section{Conclusion}
    
    \subsection{The Accomplishments}
    
    \subsection{The shortcomings}

=head1 TO-DO

=over 4

=item * Add support for passing options to \documentclass.

=item * Add support for \frontmatter, \backmatter, etc.

=item * Add support for arguments to packages.

=item * Add support for \tableofcontents, \listoffigures, etc.

=back

=head1 AUTHOR

Doug Gorley C<< <gorleyd@unbc.ca> >>

=cut

my $in_file   = '' ;
my $out_file  = '' ;
my $doc_class = 'article' ;
my $indent    = 4 ;
my $maketitle = 0 ;
my $title     = 'Untitled Document' ;
my $author    = (getpwuid( $< ) )[6] || 'Unknown Author' ;
my $date      = scalar localtime ;
my @packages  = () ;
my $sec_nums  = 1 ;
my $use_part  = 0 ;
my $filter    = 0 ;
my $help      = 0 ;
my $man       = 0 ;

GetOptions( 'file|f=s'                => \$in_file,
            'out|o=s'                 => \$out_file,
            'class|c=s'               => \$doc_class,
            'indent|i=i'              => \$indent,
            'maketitle|m'             => \$maketitle,
            'title|t=s'               => \$title,
            'author|a=s'              => \$author,
            'date|d=s'                => \$date,
            'package|p=s'             => \@packages,
            'secnum!'                 => \$sec_nums,
            'part!'                   => \$use_part,
            ''                        => \$filter,
            'help|h'                  => \$help,
            'man'                     => \$man
          ) ;

$in_file ||= shift @ARGV ;

pod2usage( -verbose => 2 ) if $man ;
pod2usage( -verbose => 1 ) if $help ;

my @levels = (
               '\chapter',
               '\section',
               '\subsection',
               '\subsubsection',
               '\paragraph',
               '\subparagraph'
	     ) ;

unshift @levels, '\part' if ( $use_part && ( $doc_class eq 'book' ) ) ; 
shift @levels if $doc_class eq 'article' ;

my ( $fh_in, $fh_out ) ;

my @rows = () ;
if ( $in_file )
{
    open $fh_in, "$in_file" or die "Couldn't open $in_file: $!" ;
    @rows = <$fh_in> ;
    close $fh_in ;
}
elsif ( $filter )
{
    @rows = <STDIN> ;
}
else
{
    pod2usage( -verbose => 1 ) ;
}

if ( $out_file )
{
    open $fh_out, ">$out_file" or die "Couldn't open $out_file: $!" ;
}
else
{
    $fh_out = *STDOUT ;
}

my $header_flag = 0 ;
foreach ( @rows )
{
    chomp ;
    my $spaces = 0 ;
    if ( /^\s*$/ ) { next }

    # Print comments as-is.
    if ( /\s*%/ )
    {
        print $fh_out "$_\n" ;
        next ;
    }
    else
    {
        $header_flag++ ;
    }

    # If this is the first non-comment line with content,
    # insert the preamble here.
    if ( $header_flag == 1 )
    {
        print $fh_out "\n\\documentclass{$doc_class}\n" ;
        if ( @packages ) { print $fh_out "\n" }
        foreach ( @packages )
        {
            print $fh_out "\\usepackage{$_}\n" ;
        }
        if ( $maketitle )
        {
            print $fh_out "\n\\title{$title}\n" ;
            print $fh_out "\\author{$author}\n" ;
            print $fh_out "\\date{$date}\n" ;
        }
        print $fh_out "\n\\begin{document}\n\n" ;
        if ( $maketitle )
        {
            print $fh_out "\\maketitle\n\n" ;
        }
        $header_flag++ ;
    }
    s/&/\\&/g ;
    s/\s*$// ;
    $spaces++ while s/^\s// ;
    print $fh_out $levels[$spaces/$indent] .
                  ( $sec_nums ? '' : '*' ) . "{$_}\n\n" ;
}
print $fh_out "\\end{document}\n\n" ;
close $fh_out ;

exit 0 ;