# The LearningOnline Network
# Opening converted problems and directory listings for Daxe
#
# $Id: daxeopen.pm,v 1.15 2024/04/14 17:12:28 raeburn Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
###

package Apache::daxeopen;
use strict;

use Apache::Constants qw(:common);
use DateTime;
use Try::Tiny;
use File::stat;
use Fcntl ':mode';

use LONCAPA qw(:match);
use Apache::loncommon;
use Apache::lonnet;
use Apache::pre_xml;
use Apache::html_to_xml;
use Apache::post_xml;
use Apache::lonlocal;

sub handler {
    my $request = shift;
    my $uri = $request->uri;
    $uri =~ s{^/daxeopen}{};
    &Apache::loncommon::no_cache($request);
    my %editors = &Apache::loncommon::permitted_editors($uri);
    unless ($editors{'daxe'}) {
        $request->content_type('text/plain');
        $request->print(&mt('Daxe editor is not enabled for this Authoring Space.'));
        $request->status(403);
        return OK;
    }
    if ($uri =~ m{/$}) {
        return directory_listing($uri, $request);
    } elsif ($uri =~ m{^/priv/.*\.(task|problem|exam|quiz|assess|survey|library|xml|html|htm|xhtml|xhtm)$}) {
        return convert_problem($uri, $request);
    } elsif ($uri =~ m{^/uploaded/$match_domain/$match_courseid/(docs|supplemental)/(default|\d+)/\d+/.*\.(html|htm|xhtml|xhtm)$}) {
         return convert_problem($uri, $request);
    } else {
        # Apache should send other files directly
        $request->status(406);
        return OK;
    }
}

sub convert_problem {
    my ($uri, $request) = @_;
    if ($uri =~ m{^/priv/$match_domain/$match_username/}) {
        unless (&has_priv_access($uri)) {
            $request->content_type('text/plain');
            $request->print(&mt('Forbidden URI: [_1]',$uri));
            $request->status(403);
            return OK;
        }
    } elsif ($uri =~ m{^/uploaded/($match_domain)/($match_courseid)/}) {
        my ($posscdom,$posscnum) = ($1,$2);
        my $allowed;
        if ($env{'request.course.id'}) {
            my $cdom = $env{'course.'.$env{'request.course.id'}.'.domain'};
            my $cnum =  $env{'course.'.$env{'request.course.id'}.'.num'};
            if (($posscdom eq $cdom) && ($posscnum eq $cnum)) {
                if (&Apache::lonnet::allowed('mdc',$env{'request.course.id'})) {
                    $allowed = 1;
                }
            }
        }
        unless ($allowed) {
            $request->content_type('text/plain');
            $request->print(&mt('Forbidden URI: [_1]',$uri));
            $request->status(403);
            return OK;
        }
    }
    my $file = &Apache::lonnet::filelocation('', $uri);
    if (&Apache::lonnet::repcopy($file) eq 'ok') {
        if (! -e $file) {
            $request->print(&mt('Not found: [_1]',$uri));
            $request->status(404);
            return OK;
        }
    } else {
        $request->print(&mt('Forbidden URI: [_1]',$uri));
        $request->status(403);
        return OK;
    }
    try {
        my $warnings = 0; # no warning printed
        my $textref = &Apache::pre_xml::pre_xml($file, $warnings);
        my $case_sensitive;
        if ($uri =~ /\.(task)$/) {
          $case_sensitive = 1;
        } else {
          $case_sensitive = 0;
        }
        $textref = &Apache::html_to_xml::html_to_xml($textref, $warnings, $case_sensitive);
        my $text = &Apache::post_xml::post_xml($textref, $file, $Apache::lonnet::perlvar{'lonDocRoot'}, $warnings);
        &Apache::loncommon::content_type($request, 'text/xml', 'utf-8');
        $request->print($text);
        return OK;
    } catch {
        $request->content_type('text/plain');
        $request->print(&mt('convert failed for [_1]:',$file)." $_");
        $request->status(406);
        return OK;
    };
}

sub directory_listing {
    my ($uri, $request) = @_;
    my $res = '<?xml version="1.0" encoding="UTF-8"?>'."\n";
    my $referrer = $request->headers_in->{'Referer'};
    my ($cdom,$cnum);
    if ($env{'request.course.id'}) {
        $cdom = $env{'course.'.$env{'request.course.id'}.'.domain'};
        $cnum = $env{'course.'.$env{'request.course.id'}.'.num'};
    }    
    if ($uri eq '/') {
        $res .= "<directory name=\"/\">\n";
        if (($env{'request.course.id'}) &&
            ($referrer =~ m{\Qfile=/daxeopen/uploaded/$cdom/$cnum/\E(docs|supplemental)/(default|\d+)/(\d+)/})) {
            $res .= "<directory name=\"uploaded\"/>\n";
        } else {
            # root: let users browse /res
            $res .= "<directory name=\"priv\"/>\n";
            $res .= "<directory name=\"res\"/>\n";
        }
    } elsif ($uri =~ m{^/uploaded/(.*)$}) {
        my $rem = $1;
        $rem =~ s{/$}{};
        if (($env{'request.course.id'}) &&
            ($referrer =~ m{\Qfile=/daxeopen/uploaded/$cdom/$cnum/\E(docs|supplemental)/(default|\d+)/(\d+)/})) {
            my ($type,$folder,$rid) = ($1,$2,$3);
            if ($rem eq '') {
                $res .= "<directory name=\"uploaded\">\n";
                $res .= "<directory name=\"$cdom\"/>\n";
            } else {
                my @expected = ($cdom,$cnum,$type,$folder,$rid);
                my @rest = split(/\//,$rem);
                my $valid = 1;
                for (my $i=0; $i<@rest; $i++) {
                    unless ($rest[$i] eq $expected[$i]) {
                        $valid = 0;
                        last;
                    }
                }
                if ($valid) {
                    my $dirname = $rest[-1];
                    $res .= "<directory name=\"$dirname\">\n";
                    if (scalar(@rest) == scalar(@expected)) {
                        my $subdir = "/userfiles/$type/$folder/$rid";
                        my ($listref, $listerror) = &Apache::lonnet::dirlist($subdir,$cdom,$cnum,'',1);
                        if ($listerror) {
                            $request->content_type('text/plain');
                            $request->print(&mt('listing error: [_1]',$listerror));
                            $request->status(406);
                            return OK;
                        } elsif (scalar(@{$listref}) == 0) {
                            $request->content_type('text/plain');
                            $request->print(&mt('Not found: [_1]',$uri));
                            $request->status(404);
                            return OK;
                        } else {
                            my @lines = @{$listref};
                            my $dirpath = &LONCAPA::propath($cdom,$cnum).'/userfiles';
                            my $dirname = $uri;
                            $dirname =~ s{^.*/([^/]*)$}{$1};
                            foreach my $line (@lines) {
                                my ($path,$dom,undef,$testdir,undef,undef,undef,undef,$size,undef,$mtime) = split(/\&/,$line,12);
                                my $isdir = ($testdir & 16384);
                                $path =~ s{^$dirpath}{};
                                next if ($path eq '.' || $path eq '..');
                                $path =~ s{/$}{};
                                my $name = $path;
                                if ($isdir) {
                                    $res .= "<directory name=\"$name\"/>\n";
                                } else {
                                    next if ($name =~ /\.bak$/);
                                    my $dt = DateTime->from_epoch(epoch => $mtime);
                                    my $modified = $dt->iso8601().'Z';
                                    $res .= "<file name=\"$name\" size=\"$size\" modified=\"$modified\"/>\n";
                                }
                            }
                        }
                    } else {
                       my $nextidx = scalar(@rest);
                       my $subdir = $expected[$nextidx];
                       $res .= "<directory name=\"$subdir\"/>"."\n";    
                    }
                } else {
                    $request->content_type('text/plain');
                    $request->print(&mt('Forbidden URI: [_1]',$uri));
                    $request->status(403);
                    return OK;
                }
            }
        } else {
            $request->content_type('text/plain');
            $request->print(&mt('Forbidden URI: [_1]',$uri));
            $request->status(403);
            return OK;
        }
    } elsif ($uri !~ m{^/(priv|res)/}) {
        $request->content_type('text/plain');
        $request->print(&mt('Not found: [_1]',$uri));
        $request->status(404);
        return OK;
    } elsif ($uri =~ m{^/res/}) {
        # NOTE: dirlist does not return an error for /res/idontexist/
	my ($listref, $listerror) = &Apache::lonnet::dirlist($uri);
	if ($listerror) {
            $request->content_type('text/plain');
            $request->print(&mt('listing error: [_1]',$listerror));
            $request->status(406);
            return OK;
	} elsif ($uri =~ m{^/res/[^/]+/$} && scalar(@{$listref}) == 0) {
            $request->content_type('text/plain');
            $request->print(&mt('Not found: [_1]',$uri));
            $request->status(404);
            return OK;
	}
        my $dirname = $uri;
        $dirname =~ s{^.*/([^/]*)$}{$1};
        $res .= "<directory name=\"$dirname/\">\n";
        my (%is_course,%is_courseauthor);
        if (ref($listref) eq 'ARRAY') {
            my @lines = @{$listref};
            foreach my $line (@lines) {
                my ($path, $dom, undef, $testdir, undef, undef, undef, undef, $size, undef, $mtime, undef, undef, undef, $obs, undef) = split(/\&/, $line, 16);
                my $isdir = ($testdir & 16384) || $dom =~ /^(user|domain)$/;
                $path =~ s{^/home/httpd/html/res/}{};
                next if $path eq '.' || $path eq '..';
                next if $path =~ /\.meta$/ || $obs || $path =~ /\.\d+\.[^.]+$/;
                if ($dom ne 'domain') {
                    my ($udom,$uname);
                    if ($dom eq 'user') {
                        ($udom) = ($uri =~ m{^/res/($match_domain)});
                        $uname = $path;
                    } else {
                        ($udom, $uname) = ($uri =~ m{^/res/($match_domain)/($match_courseid)});
                    }
                    if ($udom ne '' && $uname ne '') {
                        my $key = $udom.':'.$uname;
                        if (exists($is_course{$key})) {
                            if ($is_course{$key}) {
                                next unless ($is_courseauthor{$key});
                            }
                        } else {
                            if (&Apache::lonnet::is_course($udom, $uname)) {
                                $is_course{$key} = 1;
                                if ($env{'request.course.id'}) {
                                    my $cdom = $env{'course.'.$env{'request.course.id'}.'.domain'};
                                    my $cnum = $env{'course.'.$env{'request.course.id'}.'.num'};
                                    if (($cdom eq $udom) && ($cnum eq $uname)) {
                                        if (&Apache::lonnet::allowed('mdc', $env{'request.course.id'})) {
                                            $is_courseauthor{$key} = 1;
                                        }
                                    }
                                }
                                # remove courses from the list
                                next unless ($is_courseauthor{$key});
                            } else {
                                $is_course{$key} = 0;
                            }
                        }
                    }
                }
                $path =~ s{/$}{};
                my $name = $path;
                if ($isdir) {
                    $res .= "<directory name=\"$name\"/>\n";
                } else {
                    my $dt = DateTime->from_epoch(epoch => $mtime);
                    my $modified = $dt->iso8601().'Z';
                    $res .= "<file name=\"$name\" size=\"$size\" modified=\"$modified\"/>\n";
                }
            }
        }
    } elsif ($uri eq '/priv/') {
        my $defdom = &get_defdom($referrer);
        if (!defined $defdom) {
            $request->content_type('text/plain');
            $request->print(&mt('Forbidden URI: [_1]',$uri));
            $request->status(403);
            return OK;
        }
        $res .= "<directory name=\"priv\">\n";
        $res .= "<directory name=\"$defdom\"/>\n";
    } elsif ($uri =~ m{^/priv/($match_domain)/$}) {
        my $domain = $1;
        my $defdom = &get_defdom($referrer);
        if ($domain ne $defdom) {
            $request->content_type('text/plain');
            $request->print(&mt('Forbidden URI: [_1]',$uri));
            $request->status(403);
            return OK;
        }
        my $defname = &get_defname($domain,$referrer);
        $res .= "<directory name=\"$domain\">\n";
        $res .= "<directory name=\"$defname\"/>\n";
    } elsif ($uri =~ m{^/priv/($match_domain)\/($match_username)/}) {
        unless (&has_priv_access($uri)) {
            $request->content_type('text/plain');
            $request->print(&mt('Forbidden URI: [_1]',$uri));
            $request->status(403);
            return OK;
        }
        my $dirpath = &Apache::lonnet::filelocation('', $uri);
        if (! -e $dirpath) {
            $request->content_type('text/plain');
            $request->print(&mt('Not found: [_1]',$uri));
            $request->status(404);
            return OK;
        }
        $dirpath =~ s{/$}{};
        my @files;
        if (opendir(my $dir, $dirpath)) {
            @files = readdir($dir);
            closedir($dir);
        } else {
            $request->content_type('text/plain');
            $request->print(&mt('Error opening directory: [_1]',$dirpath));
            $request->status(403);
            return OK;
        }
        my $dirname = $dirpath;
        $dirname =~ s{^.*/([^/]*)$}{$1};
        $res .= "<directory name=\"$dirname\">\n";
        foreach my $name (@files) {
            if ($name eq '.' || $name eq '..') {
                next;
            }
            if ($name =~ /\.(bak|log|meta|save)$/) {
                next;
            }
            my $sb = stat($dirpath.'/'.$name);
            my $mode = $sb->mode;
            if (S_ISDIR($mode)) {
                $res .= "<directory name=\"$name\"/>\n";
            } else {
                $res .= "<file name=\"$name\"";
                my $size = $sb->size; # total size of file, in bytes
                $res .= " size=\"$size\"";
                my $mtime = $sb->mtime; # last modify time in seconds since the epoch
                my $dt = DateTime->from_epoch(epoch => $mtime);
                my $modified = $dt->iso8601().'Z';
                $res .= " modified=\"$modified\"";
                $res .= "/>\n";
            }
        }
    } else {
        $request->content_type('text/plain');
        $request->print(&mt('Not found: [_1]',$uri));
        $request->status(404);
        return OK;
    }
    $res .= "</directory>\n";
    &Apache::loncommon::content_type($request, 'text/xml', 'utf-8');
    $request->print($res);
    return OK;
}

sub has_priv_access {
    my ($uri) = @_; 
    my ($ownername,$ownerdom,$ownerhome) =
        &Apache::lonnet::constructaccess($uri);
    my $allowed;
    if (($ownername ne '') && ($ownerdom ne '') && ($ownerhome ne '')) {
        unless ($ownerhome eq 'no_host') {
            my @hosts = &Apache::lonnet::current_machine_ids();
            if (grep(/^\Q$ownerhome\E$/,@hosts)) {
                $allowed = 1;
            }
        }
    }
    return $allowed;
}

sub get_defdom {
    my ($referrer) = @_;
    my $defdom;
    if ($env{'request.role'} =~ m{^au\./($match_domain)/$}) {
        $defdom = $1;
    } elsif ($env{'request.role'} =~ m{^(?:ca|aa)\.($match_domain)/($match_username)$}) {
        $defdom = $1;
    } elsif ($env{'request.course.id'}) {
        if ($referrer =~ m{\Qfile=/daxeopen/priv/\E($match_domain)/($match_username)/}) {
            my ($possdom,$possuname) = ($1,$2);
            if (&Apache::lonnet::is_course($possdom,$possuname)) {
                my $crsurl = &Apache::lonnet::courseid_to_courseurl($env{'request.course.id'});
                if ($crsurl eq "/$possdom/$possuname") {
                    $defdom = $possdom;
                }
            } else {
                if (&Apache::lonnet::domain($possdom) ne '') {
                    $defdom = $possdom;
                }
            }
        }
    }
    if ($defdom eq '') {
        my ($is_adv,$is_author) = &Apache::lonnet::is_advanced_user($env{'user.domain'},$env{'user.name'});
        if ($is_author) {
            $defdom = $env{'user.domain'};
        }
    }
    return $defdom;
}

sub get_defname {
    my ($domain,$referrer) = @_;
    my $defname;
    if ($env{'request.role'} eq "au./$domain/") {
        $defname = $env{'user.name'};
    } elsif ($env{'request.role'} =~ m{^(?:ca|aa)\./\Q$domain\E/($match_username)$}) {
        $defname = $1;
    } elsif ($env{'request.course.id'}) {
        if ($referrer =~ m{\Qfile=/daxeopen/priv/\E($match_domain)/($match_username)/}) {
            my ($possdom,$possuname) = ($1,$2);
            if ($domain eq $possdom) {
                if (&Apache::lonnet::is_course($possdom,$possuname)) {
                     my $crsurl = &Apache::lonnet::courseid_to_courseurl($env{'request.course.id'});
                     if ($crsurl eq "/$possdom/$possuname") {
                        $defname = $possuname;
                    }
                } else {
                    unless (&Apache::lonnet::homeserver($possuname,$possdom) eq 'no_host') {
                        $defname = $possuname;
                    }
                }
            }
        }
    }
    if ($defname eq '') {
        my ($is_adv,$is_author) = &Apache::lonnet::is_advanced_user($domain,$env{'user.name'});
        if ($is_author) {
            $defname = $env{'user.name'};
        }
    }
    return $defname;
}

1;
__END__