#!/usr/bin/perl

undef $/;
#$/='';

open(F,"|prel -a") or die;
while(<>){
 $_ = sp2tex($_);

 s{\n(=\.)(=+)[ \t]*(.*)}{\n$2 $3\n$1 $3}g;

 s{ \n=\.[ \t]*(.*)
    (\n(.|\n)*?)
    (?=\n(?:=|\d\.))}
  { my ($a,$b)=($1,$2);
    if($a){
      if($b =~ /Verbatim/){ "\n\\begin{frame}[fragile]\\frametitle{$a}\n$b\\end{frame}\n"}
      else{ "\n\\begin{frame}\\frametitle{$a}\n$b\\end{frame}\n"}}
    else{
      if($b =~ /Verbatim/){ "\n\\begin{frame}[fragile]\n$b\\end{frame}\n"}
      else{ "\n\\begin{frame}\n$b\\end{frame}\n"}}
  }xeg; 

 s{\n=\.}{}g;
 s{\n(:\n[ \t]*\.)}{\\$1}g;

 print F $_;
}
#  {\n\\begin{frame}[fragile]\n\\frametitle{$1}


sub math2html{
  my $f=shift;
#  $f =~ s/\&/\&/g;
  $f =~ s/-->/\\rightarrow /g;           # a --> b
  $f =~ s/<--/\\leftarrow /g;            # a <-- b
  $f =~ s!/\\!\\and !g;                  # a /\ b
  $f =~ s!\\/!\\vee !g;                  # a \/ b
  $f =~ s/==>/\\doublerightarrow /g;     # a ==> b
  $f =~ s/<==/\\doubleleftarrow /g;      # a <== b
#  $f =~ s/</\&lt;/g;
#  $f =~ s/>/\&gt;/g;
  $f;
}

sub  txt2html{
  my $f=shift;
  $f =~ s/\n +<hr> *\n/\n---hr---\n/g;
  $f =~ s/\&/\\&/g;
#  $f =~ s/</\&lt;/g;
#  $f =~ s/>/\&gt;/g;
  $f =~ s/\n---hr---\n/\hrule\n/g;
  $f;
}

sub markLi{ my $a=shift;
  for($a){ s{\n\s*\.\d?(.*?)(?=(\n\s*\.|$))}{\\item $1}gs; }
  $a
}

sub sp2tex {
   my $pagina = shift; 
   my %verb=();
   my $n=0;
   my $orange="green";

   if ($pagina) {
     for ($pagina) {
       s/\cM//g;
       s/[ \t]+\n/\n/g;

       # delete after __END__
       s/\n__END__.*/\n/s;
       s/(\\end\{document\}).*/$1\n/s;

       #Verbatim paragraphs
       s{(\\begin\{Verbatim\}[^\n]*)(.*?)(\\end\{Verbatim\})}{
          $verb{++$n}= $1.txt2html($2).$3;
          "\n\n\caMARCA\ca$n\n"}segi;

       #Verbatim paragraphs
       s{\n\n([ \t]+\S.*?)(?=\s*\n\S|$)}{
          $verb{++$n}= "\\begin{Verbatim}\n".txt2html($1)."\n\\end{Verbatim}";
          "\n\n\caMARCA\ca$n\n"}seg;

       # Hard rule
       s/(\n)---+[^\n+]*($|\n)/$1\\hrule\n/g;


       # bolds, italics, tts, wiki-like
#       s!__([^_]+)__!<b><i>$1</i></b>!g;
       s!_\((.+?)\)_!"\\color{$orange}\\(".math2html($1)."\\)\\color{black}"!eg;
       s!_\[(.+?)\]_!"\n\\color{$orange}\\(".math2html($1)."\\)\\color{black}\n"!eg;
#       s!==(.+?)==!"<b><tt>".txt2html($1)."</tt></b>"!eg;
       s!\b_\B((?:[^_\n]|\B_\B)+)\B_\b!\\emph{$1}!g;
       s!\B=\b([^=\n]+)\b=\B!"\\texttt{".txt2html($1)."}"!eg;
       s!\*(\[|\b)([^*]+)(\]|\b)\*!\\color{$orange}$2\\color{black}!g;

       # Links...
#       s#\[!img\[(.+?)\]\]#<img src="$1"/>#g;
#       s#\[!wimg\[(.+?)\]\]#<img width="100%" src="$1"/>#g;

       s/\n\x01MARCA\x01(\d+)\n/$verb{$1}/g;
     }
     return $pagina;
   } else {
     return "";
   }
}


__END__

=head1 NAME

brev2s - slide wiki...

=head1 SYNOPSIS

 brev2s f

=head1 DESCRIPTION

 = section title
 == subsection title
 =. slide title
 =.== slide title and section at the same time

=head2 EXPORT


=head1 AUTHOR

J.Joao Almeida, jj@di.uminho.pt

=head1 SEE ALSO

perl(1).

=cut