# The LearningOnline Network with CAPA
# Page Handler
#
# (TeX Content Handler
#
# 05/29/00,05/30 Gerd Kortemeyer)
# 08/30,08/31,09/06,09/14,09/15,09/16,09/19,09/20,09/21 Gerd Kortemeyer

package Apache::lonpage;

use strict;
use Apache::Constants qw(:common :http);
use Apache::lonnet();
use HTML::TokeParser;
use GDBM_File;

# -------------------------------------------------------------- Module Globals
my %hash;
my @rows;

# ------------------------------------------------------------------ Euclid gcd

sub euclid {
    my ($e,$f)=@_;
    my $a; my $b; my $r;
    if ($e>$f) { $b=$e; $r=$f; } else { $r=$e; $b=$f; }
    while ($r!=0) {
	$a=$b; $b=$r;
        $r=$a%$b;
    }
    return $b;
}

# ------------------------------------------------------------ Build page table

sub tracetable {
    my ($sofar,$rid,$beenhere)=@_;
    my $further=$sofar;
    unless ($beenhere=~/\&$rid\&/) {
       $beenhere.=$rid.'&';  

       if (defined($hash{'is_map_'.$rid})) {
           if ((defined($hash{'map_start_'.$hash{'src_'.$rid}})) &&
               (defined($hash{'map_finish_'.$hash{'src_'.$rid}}))) {
              my $frid=$hash{'map_finish_'.$hash{'src_'.$rid}};
	      $sofar=
                &tracetable($sofar,$hash{'map_start_'.$hash{'src_'.$rid}},
                '&'.$frid.'&');
              $sofar++;
              if ($hash{'src_'.$frid}) {
               my $brepriv=&Apache::lonnet::allowed('bre',$hash{'src_'.$frid});
               if (($brepriv eq '2') || ($brepriv eq 'F')) {
                 if (defined($rows[$sofar])) {
                   $rows[$sofar].='&'.$frid;
                 } else {
                   $rows[$sofar]=$frid;
                 }
	       }
	      }
	   }
       } else {
          $sofar++;
          if ($hash{'src_'.$rid}) {
           my $brepriv=&Apache::lonnet::allowed('bre',$hash{'src_'.$rid});
           if (($brepriv eq '2') || ($brepriv eq 'F')) {
             if (defined($rows[$sofar])) {
               $rows[$sofar].='&'.$rid;
             } else {
               $rows[$sofar]=$rid;
             }
	   }
          }
       }

       if (defined($hash{'to_'.$rid})) {
          map {
              my $now=&tracetable($sofar,$hash{'goesto_'.$_},$beenhere);
              if ($now>$further) { $further=$now; }
          } split(/\,/,$hash{'to_'.$rid});
       }
    }
    return $further;
}

# ================================================================ Main Handler

sub handler {
  my $r=shift;

# ------------------------------------------- Set document type for header only

  if ($r->header_only) {
       if ($ENV{'browser.mathml'}) {
           $r->content_type('text/xml');
       } else {
           $r->content_type('text/html');
       }
       $r->send_http_header;
       return OK;
   }

  my $requrl=$r->uri;
# ----------------------------------------------------------------- Tie db file
  if ($ENV{'request.course.fn'}) {
      my $fn=$ENV{'request.course.fn'};
      if (-e "$fn.db") {
          if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER,0640)) {
# ------------------------------------------------------------------- Hash tied
              my $firstres=$hash{'map_start_'.$requrl};
              my $lastres=$hash{'map_finish_'.$requrl};
              if (($firstres) && ($lastres)) {
# ----------------------------------------------------------------- Render page

                  @rows=();

                  &tracetable(0,$firstres,'&'.$lastres.'&');
                  if ($hash{'src_'.$lastres}) {
                     my $brepriv=
                        &Apache::lonnet::allowed('bre',$hash{'src_'.$lastres});
                     if (($brepriv eq '2') || ($brepriv eq 'F')) {
                        $rows[$#rows+1]=''.$lastres;
		     }
		  }

                  my $i;
                  my $j;
                  my $lcm=1;
                  my $contents=0;
                  my $nforms=0;
                  
                  my %ssibody=();
                  my %ssibgcolor=();
                  my %ssitext=();
                  my %ssilink=();
                  my %ssivlink=();
                  my %ssialink=();
                  my %cellemb=();

                  my $allscript='';
                  my $allmeta='';

                  my $isxml=0;
                  my $xmlheader='';
                  my $xmlbody='';

# --------------------------------------------- Get SSI output, post parameters

                  for ($i=0;$i<=$#rows;$i++) {
		     if ($rows[$i]) {
		      $contents++;
                      my @colcont=split(/\&/,$rows[$i]);
                      $lcm*=($#colcont+1)/euclid($lcm,($#colcont+1));
                      map {
                          my $src=$hash{'src_'.$_};
                          $src=~/\.(\w+)$/;
                          $cellemb{$_}=Apache::lonnet::fileembstyle($1);
                          if ($cellemb{$_} eq 'ssi') {
# --------------------------------------------------------- This is an SSI cell
			      my $prefix=$_.'_';
                              my %posthash=('request.prefix' => $prefix);
                              if (($ENV{'$form.'.$prefix.'submit'}) 
                               || ($ENV{'form.all_submit'})) {
                               map {
				  if ($_=~/^form.$prefix/) {
				      my $name=$_;
                                      $name=~s/^form.$prefix//;
                                      $posthash{$name}=$ENV{$_};
                                  }
                               } keys %ENV;
			      }
                              my $output=Apache::lonnet::ssi($src,%posthash);
                              my $parser=HTML::TokeParser->new(\$output);
                              my $token;
                              my $bodydef=0;
                              my $thisxml=0;
                              if ($output=~/\?xml/) {
                                 $isxml=1;
                                 $thisxml=1;
                                 $output=~
         /((?:\<(?:\?xml|\!DOC|html)[^\>]*(?:\>|\>\]\>)\s*)+)\<body[^\>]*\>/si;
                                 $xmlheader=$1;
			      }
                              while (($bodydef==0) &&
                                     ($token=$parser->get_token)) {
				  if ($token->[1] eq 'body') {
				      $bodydef=1;
                                      $ssibgcolor{$_}=$token->[2]->{'bgcolor'};
                                      $ssitext{$_}=$token->[2]->{'text'};
                                      $ssilink{$_}=$token->[2]->{'link'};
                                      $ssivlink{$_}=$token->[2]->{'vlink'};
                                      $ssialink{$_}=$token->[2]->{'alink'};
                                      if ($thisxml) {
					  $xmlbody=$token->[4];
                                      }
                                  }
                                  if ($token->[1] eq 'meta') {
				      $allmeta.="\n".$token->[4].'</meta>';
                                  }
                                  if ($token->[1] eq 'script') {
				      $allscript.="\n\n"
                                                .$parser->get_text('/script');
                                  }
                              }
                              if ($output=~/\<body[^\>]*\>(.*)/si) {
                                 $output=$1; 
                              }
                              $output=~s/\<\/body\>.*//si;
                              if ($output=~/\<form/si) {
				  $nforms++;
                                  $output=~s/\<form[^\>]*\>//gsi;
                                  $output=~s/\<\/form[^\>]*\>//gsi;
                              }
			      $ssibody{$_}=$output;

# ---------------------------------------------------------------- End SSI cell
                          }
                      } @colcont;
                     } 
                  }
                  unless ($contents) {
                      $r->content_type('text/html');
                      $r->send_http_header;
                      $r->print('<html><body>Empty page.</body></html>');
                  } else {
# ------------------------------------------------------------------ Build page

# ---------------------------------------------------------------- Send headers
                      if ($isxml) {
			  $r->content_type('text/xml');
                          $r->send_http_header;
                          $r->print($xmlheader);
		      } else {
                          $r->content_type('text/html');
                          $r->send_http_header;
                          $r->print('<html>');
		      }
# ------------------------------------------------------------------------ Head
                      $r->print("\n<head>\n".$allmeta);
                      if ($allscript) {
			  $r->print("\n<script>\n".$allscript."\n</script>\n");
                      }
                      $r->print("\n</head>\n");
# ------------------------------------------------------------------ Start body
                      if ($isxml) {
                          $r->print($xmlbody);
                      } else {
			  $r->print('<body bgcolor="#FFFFFF">');
                      }

# ------------------------------------------------------------------ Start form
                      if ($nforms) {
			  $r->print('<form method="post" action="'.
				    $requrl.'">');
                      }
# ----------------------------------------------------------------- Start table
                      $r->print('<table cols="'.$lcm.'" border="0">');
                      for ($i=0;$i<=$#rows;$i++) {
			if ($rows[$i]) {
                          $r->print("\n<tr>");
                          my @colcont=split(/\&/,$rows[$i]);
                          my $avespan=$lcm/($#colcont+1);
                          for ($j=0;$j<=$#colcont;$j++) {
                              my $rid=$colcont[$j];
                              $r->print('<td colspan="'.$avespan.'"');
                              if ($cellemb{$rid} eq 'ssi') {
				  if ($ssibgcolor{$rid}) {
                                     $r->print(' bgcolor="'.
                                               $ssibgcolor{$rid}.'"');
                                  }
                                  $r->print('><font');
                                  if ($ssitext{$rid}) {
				     $r->print(' text="'.$ssitext{$rid}.'"');
                                  }
                                  if ($ssilink{$rid}) {
				     $r->print(' link="'.$ssilink{$rid}.'"');
                                  }
                                  if ($ssitext{$rid}) {
				     $r->print(' vlink="'.$ssivlink{$rid}.'"');
                                  }
                                  if ($ssialink{$rid}) {
				     $r->print(' alink="'.$ssialink{$rid}.'"');
                                  }
                            
                                  $r->print('>'.$ssibody{$rid}.'</font>');
                              } elsif ($cellemb{$rid} eq 'img') {
                                  $r->print('><img src="'.
                                    $hash{'src_'.$rid}.'"></img>');
			      }
                              $r->print('</td>');
                          }
                          $r->print('</tr>');
		        }
                      }
                      $r->print("\n</table>");
# ---------------------------------------------------------------- Submit, etc.
                      if ($nforms) {
                          $r->print(
	                  '<input name="all_submit" value="Submit All" type="'.
			  (($nforms>1)?'submit':'hidden').'"></input></form>');
                      }
                      $r->print('</body></html>');
# -------------------------------------------------------------------- End page
                  }                  
# ------------------------------------------------------------- End render page
              } else {
                  $r->content_type('text/html');
                  $r->send_http_header;
		  $r->print('<html><body>Page undefined.</body></html>');
              }
# ------------------------------------------------------------------ Untie hash
              unless (untie(%hash)) {
                   &Apache::lonnet::logthis("<font color=blue>WARNING: ".
                       "Could not untie coursemap $fn (browse).</font>"); 
              }
# -------------------------------------------------------------------- All done
	      return OK;
# ----------------------------------------------- Errors, hash could no be tied
          }
      } 
  }
  $ENV{'user.error.msg'}="$requrl:bre:1:1:Course not initialized";
  return HTTP_NOT_ACCEPTABLE; 
}

1;
__END__







<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>500 Internal Server Error</title>
</head><body>
<h1>Internal Server Error</h1>
<p>The server encountered an internal error or
misconfiguration and was unable to complete
your request.</p>
<p>Please contact the server administrator at 
 root@localhost to inform them of the time this error occurred,
 and the actions you performed just before this error.</p>
<p>More information about this error may be available
in the server error log.</p>
</body></html>