#!/usr/bin/perl

$homepage = 'http://www.tu-harburg.de/~semb2204/dlhp/';

$t_next = 'Weiter';
$t_prev = 'Zurck';
$t_toc = 'Inhalt';
$t_home = 'DLHP';


sub produce_link
{
  $next = '';
  $prev = '';
  $toc = '';
  while ($zw = <IN>)
  {
      $next = $1 if ($zw =~ /<A HREF=\"(.*?)\"><IMG SRC=\"next.gif\"/);
      $prev = $1 if ($zw =~ /<A HREF=\"(.*?)\"><IMG SRC=\"prev.gif\"/);
      $toc = $1 if ($zw =~ /<A HREF=\"(.*?)\"><IMG SRC=\"toc.gif\"/);
  }

  $head = '';  
  $head = "<LINK REL=next HREF=\"$next\" TITLE=\"$t_next\">\n" if $next;
  $head .= "<LINK REL=previous HREF=\"$prev\" TITLE=\"$t_prev\">\n" if $prev;
  $head .= "<LINK REL=toc HREF=\"$toc\" TITLE=\"$t_toc\">\n" if $toc;
  $head .= "<LINK REL=home HREF=\"$homepage\" TITLE=\"$t_home\">\n" if $homepage;
}


foreach $file (@ARGV)
{
  if ($file =~ /(.*)\.html/)
  {
    open (IN, "< $file");
    &produce_link;
    close (IN);

    open (IN, "< $file");
    $ch_file = '';
    while ($zw = <IN>)
    {
      $ch_file .= $head if ($zw =~ /<\/HEAD>/);
      $ch_file .= $zw;
    }
    close (IN);

    open (IN, "> $file");
    print IN $ch_file;
    close (IN);
  }
}
