# The LearningOnline Network with CAPA
# XML Parser Module 
#
# last modified 06/26/00 by Alexander Sakharuk

package Apache::lonxml; 

use strict;
use HTML::TokeParser;
use Safe;
use Opcode;

sub register {
  my $space;
  my @taglist;
  my $temptag;
  ($space,@taglist) = @_;
  foreach $temptag (@taglist) {
    $Apache::lonxml::alltags{$temptag}=$space;
  }
}
                                     
use Apache::style;
use Apache::lontexconvert;
use Apache::run;
use Apache::londefdef;
use Apache::scripttag;
#==================================================   Main subroutine: xmlparse  
@Apache::lonxml::pwd=();
$Apache::lonxml::outputstack = '';
$Apache::lonxml::redirection = 1;

sub xmlparse {

 my ($target,$content_file_string,$safeinit,%style_for_target) = @_;
 my @pars = ();
 @Apache::lonxml::pwd=();
 my $pwd=$ENV{'request.filename'};
 $pwd =~ s:/[^/]*$::;
 &newparser(\@pars,\$content_file_string,$pwd);
 my $currentstring = '';
 my $finaloutput = ''; 
 my $newarg = '';
 my $result;

 my $safeeval = new Safe;
 $safeeval->permit("entereval");
 $safeeval->permit(":base_math");
 $safeeval->deny(":base_io");
#need to inspect this class of ops
# $safeeval->deny(":base_orig");
 $safeinit .= ';$external::target='.$target.';';
 $safeinit .= ';$external::randomseed='.&Apache::lonnet::rndseed().';';
 &Apache::run::run($safeinit,$safeeval);
#-------------------- Redefinition of the target in the case of compound target

 ($target, my @tenta) = split('&&',$target);

 my @stack = (); 
 my @parstack = ();
 &initdepth;
 my $token;
 while ( $#pars > -1 ) {
   while ($token = $pars[$#pars]->get_token) {
     if ($token->[0] eq 'T') {
       $result=$token->[1];
#       $finaloutput .= &Apache::run::evaluate($token->[1],$safeeval,'');
     } elsif ($token->[0] eq 'S') {
       # add tag to stack 	    
       push (@stack,$token->[1]);
       # add parameters list to another stack
       push (@parstack,&parstring($token));
       &increasedepth($token);       
       if (exists $style_for_target{$token->[1]}) {

	if ($Apache::lonxml::redirection == 1) {
	  $finaloutput .= &recurse($style_for_target{$token->[1]},
		  		  $target,$safeeval,\%style_for_target,
	 		 	  @parstack);
        } else {
          $Apache::lonxml::outputstack .=  &recurse($style_for_target{$token->[1]},
		  		  $target,$safeeval,\%style_for_target,
	 		 	  @parstack);
        }

       } else {
	 $result = &callsub("start_$token->[1]", $target, $token,\@parstack,
			       \@pars, $safeeval, \%style_for_target);
       }              
     } elsif ($token->[0] eq 'E')  {
       #clear out any tags that didn't end
       while ($token->[1] ne $stack[$#stack] 
	      && ($#stack > -1)) {pop @stack;pop @parstack;&decreasedepth($token);}
       
       if (exists $style_for_target{'/'."$token->[1]"}) {

	if ($Apache::lonxml::redirection == 1) {
	 $finaloutput .= &recurse($style_for_target{'/'."$token->[1]"},
				  $target,$safeeval,\%style_for_target,
				  @parstack);
        } else {
         $Apache::lonxml::outputstack .=  &recurse($style_for_target{'/'."$token->[1]"},
				  $target,$safeeval,\%style_for_target,
				  @parstack);
        }

       } else {
	 $result = &callsub("end_$token->[1]", $target, $token, \@parstack,
			       \@pars,$safeeval, \%style_for_target);
       }
     }
     if ($result ne "") {
       if ( $#parstack > -1 ) {
 
	if ($Apache::lonxml::redirection == 1) {
	 $finaloutput .= &Apache::run::evaluate($result,$safeeval,
						$parstack[$#parstack]);
        } else {
         $Apache::lonxml::outputstack .= &Apache::run::evaluate($result,$safeeval,
						$parstack[$#parstack]);
        }

       } else {
	 $finaloutput .= &Apache::run::evaluate($result,$safeeval,'');
       }
       $result = '';
     } else {
         $finaloutput .= $result;
     }
     if ($token->[0] eq 'E') { pop @stack;pop @parstack;&decreasedepth($token);}
   }
   pop @pars;
   pop @Apache::lonxml::pwd;
 }

 return $finaloutput;
}

sub recurse {
  
  my @innerstack = (); 
  my @innerparstack = ();
  my ($newarg,$target,$safeeval,$style_for_target,@parstack) = @_;
  my @pat = ();
  &newparser(\@pat,\$newarg);
  my $tokenpat;
  my $partstring = '';
  my $output='';
  my $decls='';
  while ( $#pat > -1 ) {
    while  ($tokenpat = $pat[$#pat]->get_token) {
      if ($tokenpat->[0] eq 'T') {
	$partstring = $tokenpat->[1];
      } elsif ($tokenpat->[0] eq 'S') {
	push (@innerstack,$tokenpat->[1]);
	push (@innerparstack,&parstring($tokenpat));
	&increasedepth($tokenpat);
	$partstring = &callsub("start_$tokenpat->[1]", 
			       $target, $tokenpat, \@innerparstack,
			       \@pat, $safeeval, $style_for_target);
      } elsif ($tokenpat->[0] eq 'E') {
	#clear out any tags that didn't end
	while ($tokenpat->[1] ne $innerstack[$#innerstack] 
	       && ($#innerstack > -1)) {pop @innerstack;pop @innerparstack;
					&decreasedepth($tokenpat);}
	$partstring = &callsub("end_$tokenpat->[1]",
			       $target, $tokenpat, \@innerparstack,
			       \@pat, $safeeval, $style_for_target);
      }
      #pass both the variable to the style tag, and the tag we 
      #are processing inside the <definedtag>
      if ( $partstring ne "" ) {
	if ( $#parstack > -1 ) { 
	  if ( $#innerparstack > -1 ) { 
	    $decls= $parstack[$#parstack].$innerparstack[$#innerparstack];
	  } else {
	    $decls= $parstack[$#parstack];
	  }
	} else {
	  if ( $#innerparstack > -1 ) { 
	    $decls=$innerparstack[$#innerparstack];
	  } else {
	    $decls='';
	  }
	}
	$output .= &Apache::run::evaluate($partstring,$safeeval,$decls);
	$partstring = '';
      }
      if ($tokenpat->[0] eq 'E') { pop @innerstack;pop @innerparstack;
				 &decreasedepth($tokenpat);}
    }
    pop @pat;
    pop @Apache::lonxml::pwd;
  }
  return $output;
}

sub callsub {
  my ($sub,$target,$token,$parstack,$parser,$safeeval,$style)=@_;
  my $currentstring='';
  {
      my $sub1;
    no strict 'refs';
    if (my $space=$Apache::lonxml::alltags{$token->[1]}) {
      #&Apache::lonxml::debug("Calling sub $sub in $space<br>\n");
      $sub1="$space\:\:$sub";
      $Apache::lonxml::curdepth=join('_',@Apache::lonxml::depthcounter);
      $currentstring = &$sub1($target,$token,$parstack,$parser,
			     $safeeval,$style);
    } else {
      #&Apache::lonxml::debug("NOT Calling sub $sub in $space<br>\n");
      if (defined($token->[4])) {
	$currentstring = $token->[4];
      } else {
	$currentstring = $token->[2];
      }
    }
    use strict 'refs';
  }
  return $currentstring;
}

sub initdepth {
  @Apache::lonxml::depthcounter=();
  $Apache::lonxml::depth=-1;
  $Apache::lonxml::olddepth=-1;
}

sub increasedepth {
  my ($token) = @_;
  if ($Apache::lonxml::depth<$Apache::lonxml::olddepth-1) {
    $#Apache::lonxml::depthcounter--;
    $Apache::lonxml::olddepth=$Apache::lonxml::depth;
  }
  $Apache::lonxml::depth++;
#  print "<br>s $Apache::lonxml::depth : $Apache::lonxml::olddepth : $token->[1]<br>\n";
  $Apache::lonxml::depthcounter[$Apache::lonxml::depth]++;
  if ($Apache::lonxml::depthcounter[$Apache::lonxml::depth]==1) {
    $Apache::lonxml::olddepth=$Apache::lonxml::depth;
  }
}

sub decreasedepth {
  my ($token) = @_;
  $Apache::lonxml::depth--;
#  print "<br>e $Apache::lonxml::depth : $Apache::lonxml::olddepth : $token->[1]<br>\n";
}

sub get_all_text {

 my($tag,$pars)= @_;
 my $depth=0;
 my $token;
 my $result='';
 my $tag=substr($tag,1); #strip the / off the tag
# &Apache::lonxml::debug("have:$tag:");
 while (($depth >=0) && ($token = $pars->get_token)) {
   if ($token->[0] eq 'T') {
     $result.=$token->[1];
   } elsif ($token->[0] eq 'S') {
     if ($token->[1] eq $tag) { $depth++; }
     $result.=$token->[4];
   } elsif ($token->[0] eq 'E')  {
     if ( $token->[1] eq $tag) { $depth--; }
     #skip sending back the last end tag
     if ($depth > -1) { $result.=$token->[2]; }
   }
 }
 return $result
}

sub newparser {
  my ($parser,$contentref,$dir) = @_;
  push (@$parser,HTML::TokeParser->new($contentref));
  if ( $dir eq '' ) {
    push (@Apache::lonxml::pwd, $Apache::lonxml::pwd[$#Apache::lonxml::pwd]);
  } else {
    push (@Apache::lonxml::pwd, $dir);
  } 
#  &Apache::lonxml::debug("pwd:$#Apache::lonxml::pwd");
#  &Apache::lonxml::debug("pwd:$Apache::lonxml::pwd[$#Apache::lonxml::pwd]");
}

sub parstring {
  my ($token) = @_;
  my $temp='';
  map {
    if ($_=~/\w+/) {
      $temp .= "my \$$_=\"$token->[2]->{$_}\";"
    }
  } @{$token->[3]};
  return $temp;
}

sub handler {
  my $request=shift;

  my $target='web';
  $Apache::lonxml::debug=1;
  if ($ENV{'browser.mathml'}) {
    $request->content_type('text/xml');
  } else {
    $request->content_type('text/html');
  }
  $request->send_http_header;

  return 'OK' if $request->header_only;

  $request->print(&Apache::lontexconvert::header());

  $request->print('<body bgcolor="#FFFFFF">'."\n");

  my $file = "/home/httpd/html".$request->uri;
  my %mystyle;
  my $result = '';
  $result = Apache::lonxml::xmlparse($target, &Apache::lonnet::getfile($file),'',%mystyle);
  $request->print($result);
  $request->print('</body>');
  $request->print(&Apache::lontexconvert::footer());
  return 'OK';
}
 
$Apache::lonxml::debug=0;
sub debug {
  if ($Apache::lonxml::debug eq 1) {
    print "DEBUG:".$_[0]."<br>\n";
  }
}
sub error {
  print "ERROR:".$_[0]."<br>\n";
}
sub warning {
  if ($Apache::lonxml::debug eq 1) {
    print "WARNING:".$_[0]."<br>\n";
  }
}

1;
__END__