--- loncom/interface/lonnavmaps.pm	2001/01/03 16:20:59	1.1
+++ loncom/interface/lonnavmaps.pm	2006/03/23 22:32:10	1.374
@@ -1,41 +1,5031 @@
-# The LearningOnline Network
-# Navigate Maps
+# The LearningOnline Network with CAPA
+# Navigate Maps Handler
 #
-# (Internal Server Error Handler
+# $Id: lonnavmaps.pm,v 1.374 2006/03/23 22:32:10 albertel Exp $
 #
-# (Login Screen
-# 5/21/99,5/22,5/25,5/26,5/31,6/2,6/10,7/12,7/14,
-# 1/14/00,5/29,5/30,6/1,6/29,7/1,11/9 Gerd Kortemeyer)
+# Copyright Michigan State University Board of Trustees
 #
-# 3/1/1 Gerd Kortemeyer)
+# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
 #
-# 3/1 Gerd Kortemeyer
+# 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::lonnavmaps;
 
 use strict;
-use Apache::Constants qw(:common);
+use GDBM_File;
+use Apache::Constants qw(:common :http);
+use Apache::loncommon();
+use Apache::lonmenu();
+use Apache::lonenc();
+use Apache::lonlocal;
+use Apache::lonnet;
+use POSIX qw (floor strftime);
+use Data::Dumper; # for debugging, not always 
+use Time::HiRes qw( gettimeofday tv_interval );
+
+# symbolic constants
+sub SYMB { return 1; }
+sub URL { return 2; }
+sub NOTHING { return 3; }
+
+# Some data
+
+my $resObj = "Apache::lonnavmaps::resource";
+
+# Keep these mappings in sync with lonquickgrades, which uses the colors
+# instead of the icons.
+my %statusIconMap = 
+    (
+     $resObj->CLOSED       => '',
+     $resObj->OPEN         => 'navmap.open.gif',
+     $resObj->CORRECT      => 'navmap.correct.gif',
+     $resObj->PARTIALLY_CORRECT      => 'navmap.partial.gif',
+     $resObj->INCORRECT    => 'navmap.wrong.gif',
+     $resObj->ATTEMPTED    => 'navmap.ellipsis.gif',
+     $resObj->ERROR        => ''
+     );
+
+my %iconAltTags = 
+    ( 'navmap.correct.gif' => 'Correct',
+      'navmap.wrong.gif'   => 'Incorrect',
+      'navmap.open.gif'    => 'Open' );
+
+# Defines a status->color mapping, null string means don't color
+my %colormap = 
+    ( $resObj->NETWORK_FAILURE        => '',
+      $resObj->CORRECT                => '',
+      $resObj->EXCUSED                => '#3333FF',
+      $resObj->PAST_DUE_ANSWER_LATER  => '',
+      $resObj->PAST_DUE_NO_ANSWER     => '',
+      $resObj->ANSWER_OPEN            => '#006600',
+      $resObj->OPEN_LATER             => '',
+      $resObj->TRIES_LEFT             => '',
+      $resObj->INCORRECT              => '',
+      $resObj->OPEN                   => '',
+      $resObj->NOTHING_SET            => '',
+      $resObj->ATTEMPTED              => '',
+      $resObj->ANSWER_SUBMITTED       => '',
+      $resObj->PARTIALLY_CORRECT      => '#006600'
+      );
+# And a special case in the nav map; what to do when the assignment
+# is not yet done and due in less then 24 hours
+my $hurryUpColor = "#FF0000";
+
+sub launch_win {
+    my ($mode,$script,$toplinkitems,$firsttime)=@_;
+    my $result;
+    if ($script ne 'no') {
+	$result.='<script type="text/javascript">';
+    }
+    if ($firsttime) {
+	$result.='function launch_navmapwin() {
+                 newWindow=open(\'/adm/navmaps?launchExternalRoles\',\'loncapanav\',\'width=400,height=600,scrollbars=1\');
+               }';
+    } else {
+	$result.='function launch_navmapwin() {
+                 newWindow=open(\'/adm/navmaps?launchExternal\',\'loncapanav\',\'width=400,height=600,scrollbars=1\');
+               }';
+    }
+    if ($mode eq 'now') {
+	$result.="\nlaunch_navmapwin();\n";
+    }
+    if ($script ne 'no') {
+	$result.='</script>';
+    }
+    if ($mode eq 'link') {
+	&add_linkitem($toplinkitems,'launchnav','launch_navmapwin()',
+		      "Launch navigation window");
+    }
+    return $result;
+}
+
+sub close {
+    if ($env{'environment.remotenavmap'} ne 'on') { return ''; }
+    return(<<ENDCLOSE);
+<script type="text/javascript">
+window.status='Accessing Nav Control';
+menu=window.open("/adm/rat/empty.html","loncapanav",
+                 "height=600,width=400,scrollbars=1");
+window.status='Closing Nav Control';
+menu.close();
+window.status='Done.';
+</script>
+ENDCLOSE
+}
+
+sub update {
+    if ($env{'environment.remotenavmap'} ne 'on') { return ''; }
+    if (!$env{'request.course.id'}) { return ''; }
+    if ($ENV{'REQUEST_URI'}=~m|^/adm/navmaps|) { return ''; }
+    return(<<ENDUPDATE);
+<form name="navform"></form>
+<script type="text/javascript">
+this.document.navform.action='/adm/navmaps#curloc';
+this.document.navform.target='loncapanav';
+this.document.navform.submit();
+</script>
+ENDUPDATE
+}
 
 sub handler {
     my $r = shift;
-    $r->content_type('text/html');
+    real_handler($r);
+}
+
+sub real_handler {
+    my $r = shift;
+    #my $t0=[&gettimeofday()];
+    # Handle header-only request
+    if ($r->header_only) {
+        if ($env{'browser.mathml'}) {
+            &Apache::loncommon::content_type($r,'text/xml');
+        } else {
+            &Apache::loncommon::content_type($r,'text/html');
+        }
+        $r->send_http_header;
+        return OK;
+    }
+
+    # Send header, don't cache this page
+    if ($env{'browser.mathml'}) {
+        &Apache::loncommon::content_type($r,'text/xml');
+    } else {
+        &Apache::loncommon::content_type($r,'text/html');
+    }
+    &Apache::loncommon::no_cache($r);
+
+    my %toplinkitems=();
+    &add_linkitem(\%toplinkitems,'blank','',"Select Action");
+    if ($ENV{QUERY_STRING} eq 'collapseExternal') {
+	&Apache::lonnet::put('environment',{'remotenavmap' => 'off'});
+	&Apache::lonnet::appenv('environment.remotenavmap' => 'off');
+	my $menu=&Apache::lonmenu::reopenmenu();
+	my $navstatus=&Apache::lonmenu::get_nav_status();
+	if ($menu) {
+	    $menu=(<<MENU)
+             swmenu=$menu
+             swmenu.clearTimeout(swmenu.menucltim);
+	     $navstatus
+MENU
+        } else {
+	    my $nothing = &Apache::lonhtmlcommon::javascript_nothing();
+	    my $mainwindow='window.open('.$nothing.',"loncapaclient","",false);';
+	    $menu=(<<MENU)
+             swmenu=$mainwindow
+	     $navstatus
+MENU
+	}
+        $r->send_http_header;
+	my $js =<<"ENDSUBM";
+	  <script type="text/javascript">
+ 	    function submitthis() {
+		    $menu
+		    self.close();
+	    }
+	
+  	  </script>
+ENDSUBM
+        $r->print(&Apache::loncommon::start_page(undef,$js,
+						 {'only_body' => 1,
+						  'bgcolor'   => '#FFFFFF',
+						  'add_entries' => 
+						      'onLoad="submitthis()"',}).
+		  &Apache::loncommon::end_page());
+
+        return OK;
+    }
+    if ($ENV{QUERY_STRING} =~ /^launchExternal/) {
+	&Apache::lonnet::put('environment',{'remotenavmap' => 'on'});
+	&Apache::lonnet::appenv('environment.remotenavmap' => 'on');
+ 	my $menu=&Apache::lonmenu::reopenmenu();
+	my $navstatus=&Apache::lonmenu::get_nav_status();
+	if ($menu) {
+	    $r->print(<<MENU);
+             <script type="text/javascript">
+             swmenu=$menu
+             swmenu.clearTimeout(swmenu.menucltim);
+	     $navstatus
+             </script>
+MENU
+        }
+   }
+    if ($ENV{QUERY_STRING} eq 'turningOffExternal') {
+	$env{'environment.remotenavmap'}='off';
+    }
+
+    # Create the nav map
+    my $navmap = Apache::lonnavmaps::navmap->new();
+
+    if (!defined($navmap)) {
+        my $requrl = $r->uri;
+        $env{'user.error.msg'} = "$requrl:bre:0:0:Course not initialized";
+        return HTTP_NOT_ACCEPTABLE;
+    }
     $r->send_http_header;
-    return OK if $r->header_only;
 
-# --------------------------------------------------- Print login screen header
-    $r->print(<<ENDDOCUMENT);
-<html>
-<head>
-<title>The LearningOnline Network with CAPA</title>
-</head>
-<body bgcolor="#FFFFFF">
-<h1>Navigate Maps</h1>
-<img src="/adm/lonKaputt/lonconstruct.gif">
-</body>
-</html>
-ENDDOCUMENT
+# ------------------------------------------------------------ Get query string
+    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['register','sort','showOnlyHomework','postsymb']);
+    
+# ----------------------------------------------------- Force menu registration
+    my $addentries='';
+    my $more_unload;
+    my $body_only='';
+    my $js;
+    if ($env{'environment.remotenavmap'} eq 'on') {
+	$js='<script type="text/javascript">
+                function collapse() {
+                   this.document.location="/adm/navmaps?collapseExternal";
+                }
+             </script>';
+# FIXME need to be smarter to only catch window close events
+#	$more_unload="collapse()"
+	$body_only=1;
+    }
+    if ($env{'form.register'}) {
+	$addentries=' onLoad="'.&Apache::lonmenu::loadevents().
+	    '" onUnload="'.&Apache::lonmenu::unloadevents().';'.
+	    $more_unload.'"';
+	$r->print(&Apache::lonmenu::registerurl(1));
+    } else {
+	$addentries=' onUnload="'.$more_unload.'"';
+    }
+
+    # Header
+    $r->print(&Apache::loncommon::start_page('Navigate Course Contents',$js,
+					     {'add_entries'     => $addentries,
+					      'only_body'       => $body_only,
+					      'force_resgister' =>
+						  $env{'form.register'},}));
+    $r->print('<script type="text/javascript">window.focus();</script>');
+     
+    $r->rflush();
+
+    # Check that it's defined
+    if (!($navmap->courseMapDefined())) {
+	$r->print(&Apache::loncommon::help_open_menu('','Navigation Screen','Navigation_Screen','',undef,'RAT'));
+        $r->print('<font size="+2" color="red">'.&mt('Coursemap undefined.').
+		  '</font>' .
+                  &Apache::loncommon::end_page());
+        return OK;
+    }
+
+    # See if there's only one map in the top-level, if we don't
+    # already have a filter... if so, automatically display it
+    # (older code; should use retrieveResources)
+    if ($ENV{QUERY_STRING} !~ /filter/) {
+        my $iterator = $navmap->getIterator(undef, undef, undef, 0);
+        my $curRes;
+        my $sequenceCount = 0;
+        my $sequenceId;
+        while ($curRes = $iterator->next()) {
+            if (ref($curRes) && $curRes->is_sequence()) {
+                $sequenceCount++;
+                $sequenceId = $curRes->map_pc();
+            }
+        }
+        
+        if ($sequenceCount == 1) {
+            # The automatic iterator creation in the render call 
+            # will pick this up. We know the condition because
+            # the defined($env{'form.filter'}) also ensures this
+            # is a fresh call.
+            $env{'form.filter'} = "$sequenceId";
+        }
+    }
+
+    if ($ENV{QUERY_STRING} eq 'launchExternal') {
+	$r->print('
+          <form name="returnwin" action="/adm/flip?postdata=navlaunch%3a" 
+                method="post" target="loncapaclient">
+          </form>');
+	$r->print('
+          <script type="text/javascript">
+              this.document.returnwin.submit();
+          </script>');
+    }
+
+    if ($env{'environment.remotenavmap'} ne 'on') {
+	$r->print(&launch_win('link','yes',\%toplinkitems));
+    } 
+    if ($env{'environment.remotenavmap'} eq 'on') {
+	&add_linkitem(\%toplinkitems,'closenav','collapse()',
+		      "Close navigation window");
+    } 
+
+    my $jumpToFirstHomework = 0;
+    # Check to see if the student is jumping to next open, do-able problem
+    if ($ENV{QUERY_STRING} =~ /^jumpToFirstHomework/) {
+        $jumpToFirstHomework = 1;
+        # Find the next homework problem that they can do.
+        my $iterator = $navmap->getIterator(undef, undef, undef, 1);
+        my $curRes;
+        my $foundDoableProblem = 0;
+        my $problemRes;
+        
+        while (($curRes = $iterator->next()) && !$foundDoableProblem) {
+            if (ref($curRes) && $curRes->is_problem()) {
+                my $status = $curRes->status();
+                if ($curRes->completable()) {
+                    $problemRes = $curRes;
+                    $foundDoableProblem = 1;
+
+                    # Pop open all previous maps
+                    my $stack = $iterator->getStack();
+                    pop @$stack; # last resource in the stack is the problem
+                                 # itself, which we don't need in the map stack
+                    my @mapPcs = map {$_->map_pc()} @$stack;
+                    $env{'form.filter'} = join(',', @mapPcs);
+
+                    # Mark as both "here" and "jump"
+                    $env{'form.postsymb'} = $curRes->symb();
+                }
+            }
+        }
+
+        # If we found no problems, print a note to that effect.
+        if (!$foundDoableProblem) {
+            $r->print("<font size='+2'>All homework assignments have been completed.</font><br /><br />");
+        }
+    } else {
+	&add_linkitem(\%toplinkitems,'firsthomework',
+		      'location.href="navmaps?jumpToFirstHomework"',
+		      "Show Me My First Homework Problem");
+    }
+
+    my $suppressEmptySequences = 0;
+    my $filterFunc = undef;
+    my $resource_no_folder_link = 0;
+
+    # Display only due homework.
+    my $showOnlyHomework = 0;
+    if ($env{'form.showOnlyHomework'} eq "1") {
+        $showOnlyHomework = 1;
+        $suppressEmptySequences = 1;
+        $filterFunc = sub { my $res = shift; 
+                            return $res->completable() || $res->is_map();
+                        };
+	&add_linkitem(\%toplinkitems,'everything',
+		     'location.href="navmaps?sort='.$env{'form.sort'}.'"',
+		      "Show Everything");
+        $r->print("<p><font size='+2'>".&mt("Uncompleted Homework")."</font></p>");
+        $env{'form.filter'} = '';
+        $env{'form.condition'} = 1;
+	$resource_no_folder_link = 1;
+    } else {
+	&add_linkitem(\%toplinkitems,'uncompleted',
+		      'location.href="navmaps?sort='.$env{'form.sort'}.
+		          '&showOnlyHomework=1"',
+		      "Show Only Uncompleted Homework");
+    }
+
+    my %selected=($env{'form.sort'} => 'selected=on');
+    my $sort_html=("<form>
+                 <nobr>
+                    <input type=\"hidden\" name=\"showOnlyHomework\" value=\"".$env{'form.showOnlyHomework'}."\" />
+                    <input type=\"submit\" value=\"".&mt('Sort by:')."\" />
+                    <select name=\"sort\">
+                       <option value=\"default\" $selected{'default'}>".&mt('Default')."</option>
+                       <option value=\"title\"   $selected{'title'}  >".&mt('Title')."</option>
+                       <option value=\"duedate\" $selected{'duedate'}>".&mt('Duedate')."</option>
+                       <option value=\"discussion\" $selected{'discussion'}>".&mt('Has New Discussion')."</option>
+                    </select>
+                 </nobr>
+               </form>");
+    # renderer call
+    my $renderArgs = { 'cols' => [0,1,2,3],
+		       'sort' => $env{'form.sort'},
+                       'url' => '/adm/navmaps',
+                       'navmap' => $navmap,
+                       'suppressNavmap' => 1,
+                       'suppressEmptySequences' => $suppressEmptySequences,
+                       'filterFunc' => $filterFunc,
+		       'resource_no_folder_link' => $resource_no_folder_link,
+		       'sort_html'=> $sort_html,
+                       'r' => $r,
+                       'caller' => 'navmapsdisplay',
+                       'linkitems' => \%toplinkitems};
+    my $render = render($renderArgs);
+
+    # If no resources were printed, print a reassuring message so the
+    # user knows there was no error.
+    if ($renderArgs->{'counter'} == 0) {
+        if ($showOnlyHomework) {
+            $r->print("<p><font size='+1'>".&mt("All homework is currently completed").".</font></p>");
+        } else { # both jumpToFirstHomework and normal use the same: course must be empty
+            $r->print("<p><font size='+1'>This course is empty.</font></p>");
+        }
+    }
+    #my $td=&tv_interval($t0);
+    #$r->print("<br />$td");
+
+    $r->print(&Apache::loncommon::end_page());
+    $r->rflush();
+
     return OK;
-} 
+}
+
+# Convenience functions: Returns a string that adds or subtracts
+# the second argument from the first hash, appropriate for the 
+# query string that determines which folders to recurse on
+sub addToFilter {
+    my $hashIn = shift;
+    my $addition = shift;
+    my %hash = %$hashIn;
+    $hash{$addition} = 1;
+
+    return join (",", keys(%hash));
+}
+
+sub removeFromFilter {
+    my $hashIn = shift;
+    my $subtraction = shift;
+    my %hash = %$hashIn;
+
+    delete $hash{$subtraction};
+    return join(",", keys(%hash));
+}
+
+# Convenience function: Given a stack returned from getStack on the iterator,
+# return the correct src() value.
+sub getLinkForResource {
+    my $stack = shift;
+    my $res;
+
+    # Check to see if there are any pages in the stack
+    foreach $res (@$stack) {
+        if (defined($res)) {
+	    my $anchor;
+	    if ($res->is_page()) {
+		foreach (@$stack) { if (defined($_)) { $anchor = $_; }  }
+		$anchor=&Apache::lonnet::escape($anchor->shown_symb());
+		return ($res->link(),$res->shown_symb(),$anchor);
+	    }
+            # in case folder was skipped over as "only sequence"
+	    my ($map,$id,$src)=&Apache::lonnet::decode_symb($res->symb());
+	    if ($map=~/\.page$/) {
+		my $url=&Apache::lonnet::clutter($map);
+		$anchor=&Apache::lonnet::escape($src->shown_symb());
+		return ($url,$res->shown_symb(),$anchor);
+	    }
+        }
+    }
+
+    # Failing that, return the src of the last resource that is defined
+    # (when we first recurse on a map, it puts an undefined resource
+    # on the bottom because $self->{HERE} isn't defined yet, and we
+    # want the src for the map anyhow)
+    foreach (@$stack) {
+        if (defined($_)) { $res = $_; }
+    }
+
+    return ($res->link(),$res->shown_symb());
+}
+
+# Convenience function: This separates the logic of how to create
+# the problem text strings ("Due: DATE", "Open: DATE", "Not yet assigned",
+# etc.) into a separate function. It takes a resource object as the
+# first parameter, and the part number of the resource as the second.
+# It's basically a big switch statement on the status of the resource.
+
+sub getDescription {
+    my $res = shift;
+    my $part = shift;
+    my $status = $res->status($part);
+
+    if ($status == $res->NETWORK_FAILURE) { 
+        return &mt("Having technical difficulties; please check status later"); 
+    }
+    if ($status == $res->NOTHING_SET) {
+        return &mt("Not currently assigned.");
+    }
+    if ($status == $res->OPEN_LATER) {
+        return "Open " . timeToHumanString($res->opendate($part),'start');
+    }
+    if ($status == $res->OPEN) {
+        if ($res->duedate($part)) {
+            return &mt("Due")."  " .timeToHumanString($res->duedate($part),'end');
+        } else {
+            return &mt("Open, no due date");
+        }
+    }
+    if ($status == $res->PAST_DUE_ANSWER_LATER) {
+        return &mt("Answer open")." " . timeToHumanString($res->answerdate($part),'start');
+    }
+    if ($status == $res->PAST_DUE_NO_ANSWER) {
+        return &mt("Was due")." " . timeToHumanString($res->duedate($part),'end');
+    }
+    if (($status == $res->ANSWER_OPEN || $status == $res->PARTIALLY_CORRECT)
+	&& $res->handgrade($part) ne 'yes') {
+        return &mt("Answer available");
+    }
+    if ($status == $res->EXCUSED) {
+        return &mt("Excused by instructor");
+    }
+    if ($status == $res->ATTEMPTED) {
+        return &mt("Answer submitted, not yet graded");
+    }
+    if ($status == $res->TRIES_LEFT) {
+        my $tries = $res->tries($part);
+        my $maxtries = $res->maxtries($part);
+        my $triesString = "";
+        if ($tries && $maxtries) {
+            $triesString = "<font size=\"-1\"><i>($tries of $maxtries tries used)</i></font>";
+            if ($maxtries > 1 && $maxtries - $tries == 1) {
+                $triesString = "<b>$triesString</b>";
+            }
+        }
+        if ($res->duedate($part)) {
+            return &mt("Due")." " . timeToHumanString($res->duedate($part),'end') .
+                " $triesString";
+        } else {
+            return &mt("No due date")." $triesString";
+        }
+    }
+    if ($status == $res->ANSWER_SUBMITTED) {
+        return &mt('Answer submitted');
+    }
+}
+
+# Convenience function, so others can use it: Is the problem due in less then
+# 24 hours, and still can be done?
+
+sub dueInLessThan24Hours {
+    my $res = shift;
+    my $part = shift;
+    my $status = $res->status($part);
+
+    return ($status == $res->OPEN() ||
+            $status == $res->TRIES_LEFT()) &&
+	    $res->duedate($part) && $res->duedate($part) < time()+(24*60*60) &&
+	    $res->duedate($part) > time();
+}
+
+# Convenience function, so others can use it: Is there only one try remaining for the
+# part, with more then one try to begin with, not due yet and still can be done?
+sub lastTry {
+    my $res = shift;
+    my $part = shift;
+
+    my $tries = $res->tries($part);
+    my $maxtries = $res->maxtries($part);
+    return $tries && $maxtries && $maxtries > 1 &&
+        $maxtries - $tries == 1 && $res->duedate($part) &&
+        $res->duedate($part) > time();
+}
+
+# This puts a human-readable name on the env variable.
+
+sub advancedUser {
+    return $env{'request.role.adv'};
+}
+
+
+# timeToHumanString takes a time number and converts it to a
+# human-readable representation, meant to be used in the following
+# manner:
+# print "Due $timestring"
+# print "Open $timestring"
+# print "Answer available $timestring"
+# Very, very, very, VERY English-only... goodness help a localizer on
+# this func...
+
+
+sub timeToHumanString {
+    my ($time,$type,$format) = @_;
+
+    # zero, '0' and blank are bad times
+    if (!$time) {
+        return &mt('never');
+    }
+    unless (&Apache::lonlocal::current_language()=~/^en/) {
+	return &Apache::lonlocal::locallocaltime($time);
+    } 
+    my $now = time();
+
+    my @time = localtime($time);
+    my @now = localtime($now);
+
+    # Positive = future
+    my $delta = $time - $now;
+
+    my $minute = 60;
+    my $hour = 60 * $minute;
+    my $day = 24 * $hour;
+    my $week = 7 * $day;
+    my $inPast = 0;
+
+    # Logic in comments:
+    # Is it now? (extremely unlikely)
+    if ( $delta == 0 ) {
+        return "this instant";
+    }
+
+    if ($delta < 0) {
+        $inPast = 1;
+        $delta = -$delta;
+    }
+
+    if ( $delta > 0 ) {
+
+        my $tense = $inPast ? " ago" : "";
+        my $prefix = $inPast ? "" : "in ";
+        
+        # Less then a minute
+        if ( $delta < $minute ) {
+            if ($delta == 1) { return "${prefix}1 second$tense"; }
+            return "$prefix$delta seconds$tense";
+        }
+
+        # Less then an hour
+        if ( $delta < $hour ) {
+            # If so, use minutes
+            my $minutes = floor($delta / 60);
+            if ($minutes == 1) { return "${prefix}1 minute$tense"; }
+            return "$prefix$minutes minutes$tense";
+        }
+        
+        # Is it less then 24 hours away? If so,
+        # display hours + minutes
+        if ( $delta < $hour * 24) {
+            my $hours = floor($delta / $hour);
+            my $minutes = floor(($delta % $hour) / $minute);
+            my $hourString = "$hours hours";
+            my $minuteString = ", $minutes minutes";
+            if ($hours == 1) {
+                $hourString = "1 hour";
+            }
+            if ($minutes == 1) {
+                $minuteString = ", 1 minute";
+            }
+            if ($minutes == 0) {
+                $minuteString = "";
+            }
+            return "$prefix$hourString$minuteString$tense";
+        }
+
+	# If there's a caller supplied format, use it.
+
+	if($format ne '') {
+	    my $timeStr = strftime($format, localtime($time));
+	    return $timeStr.&Apache::lonlocal::gettimezone();
+	}
+
+        # Less then 5 days away, display day of the week and
+        # HH:MM
+
+        if ( $delta < $day * 5 ) {
+            my $timeStr = strftime("%A, %b %e at %I:%M %P", localtime($time));
+            $timeStr =~ s/12:00 am/00:00/;
+            $timeStr =~ s/12:00 pm/noon/;
+            return ($inPast ? "last " : "this ") .
+                $timeStr.&Apache::lonlocal::gettimezone();
+        }
+        
+	my $conjunction='on';
+	if ($type eq 'start') {
+	    $conjunction='at';
+	} elsif ($type eq 'end') {
+	    $conjunction='by';
+	}
+        # Is it this year?
+        if ( $time[5] == $now[5]) {
+            # Return on Month Day, HH:MM meridian
+            my $timeStr = strftime("$conjunction %A, %b %e at %I:%M %P", localtime($time));
+            $timeStr =~ s/12:00 am/00:00/;
+            $timeStr =~ s/12:00 pm/noon/;
+            return $timeStr.&Apache::lonlocal::gettimezone();
+        }
+
+        # Not this year, so show the year
+        my $timeStr = strftime("$conjunction %A, %b %e %Y at %I:%M %P", localtime($time));
+        $timeStr =~ s/12:00 am/00:00/;
+        $timeStr =~ s/12:00 pm/noon/;
+        return $timeStr.&Apache::lonlocal::gettimezone();
+    }
+}
+
+
+=pod
+
+=head1 NAME
+
+Apache::lonnavmap - Subroutines to handle and render the navigation
+    maps
+
+=head1 SYNOPSIS
+
+The main handler generates the navigational listing for the course,
+the other objects export this information in a usable fashion for
+other modules.
+
+=head1 OVERVIEW
+
+X<lonnavmaps, overview> When a user enters a course, LON-CAPA examines the
+course structure and caches it in what is often referred to as the
+"big hash" X<big hash>. You can see it if you are logged into
+LON-CAPA, in a course, by going to /adm/test. (You may need to
+tweak the /home/httpd/lonTabs/htpasswd file to view it.) The
+content of the hash will be under the heading "Big Hash".
+
+Big Hash contains, among other things, how resources are related
+to each other (next/previous), what resources are maps, which 
+resources are being chosen to not show to the student (for random
+selection), and a lot of other things that can take a lot of time
+to compute due to the amount of data that needs to be collected and
+processed.
+
+Apache::lonnavmaps provides an object model for manipulating this
+information in a higher-level fashion then directly manipulating 
+the hash. It also provides access to several auxilary functions 
+that aren't necessarily stored in the Big Hash, but are a per-
+resource sort of value, like whether there is any feedback on 
+a given resource.
+
+Apache::lonnavmaps also abstracts away branching, and someday, 
+conditions, for the times where you don't really care about those
+things.
+
+Apache::lonnavmaps also provides fairly powerful routines for
+rendering navmaps, and last but not least, provides the navmaps
+view for when the user clicks the NAV button.
+
+B<Note>: Apache::lonnavmaps I<only> works for the "currently
+logged in user"; if you want things like "due dates for another
+student" lonnavmaps can not directly retrieve information like
+that. You need the EXT function. This module can still help,
+because many things, such as the course structure, are constant
+between users, and Apache::lonnavmaps can help by providing
+symbs for the EXT call.
+
+The rest of this file will cover the provided rendering routines, 
+which can often be used without fiddling with the navmap object at
+all, then documents the Apache::lonnavmaps::navmap object, which
+is the key to accessing the Big Hash information, covers the use
+of the Iterator (which provides the logic for traversing the 
+somewhat-complicated Big Hash data structure), documents the
+Apache::lonnavmaps::Resource objects that are returned by 
+
+=head1 Subroutine: render
+
+The navmap renderer package provides a sophisticated rendering of the
+standard navigation maps interface into HTML. The provided nav map
+handler is actually just a glorified call to this.
+
+Because of the large number of parameters this function accepts,
+instead of passing it arguments as is normal, pass it in an anonymous
+hash with the desired options.
+
+The package provides a function called 'render', called as
+Apache::lonnavmaps::render({}).
+
+=head2 Overview of Columns
+
+The renderer will build an HTML table for the navmap and return
+it. The table is consists of several columns, and a row for each
+resource (or possibly each part). You tell the renderer how many
+columns to create and what to place in each column, optionally using
+one or more of the prepared columns, and the renderer will assemble
+the table.
+
+Any additional generally useful column types should be placed in the
+renderer code here, so anybody can use it anywhere else. Any code
+specific to the current application (such as the addition of <input>
+elements in a column) should be placed in the code of the thing using
+the renderer.
+
+At the core of the renderer is the array reference COLS (see Example
+section below for how to pass this correctly). The COLS array will
+consist of entries of one of two types of things: Either an integer
+representing one of the pre-packaged column types, or a sub reference
+that takes a resource reference, a part number, and a reference to the
+argument hash passed to the renderer, and returns a string that will
+be inserted into the HTML representation as it.
+
+All other parameters are ways of either changing how the columns
+are printing, or which rows are shown.
+
+The pre-packaged column names are refered to by constants in the
+Apache::lonnavmaps namespace. The following currently exist:
+
+=over 4
+
+=item * B<Apache::lonnavmaps::resource>:
+
+The general info about the resource: Link, icon for the type, etc. The
+first column in the standard nav map display. This column provides the
+indentation effect seen in the B<NAV> screen. This column also accepts
+the following parameters in the renderer hash:
+
+=over 4
+
+=item * B<resource_nolink>: default false
+
+If true, the resource will not be linked. By default, all non-folder
+resources are linked.
+
+=item * B<resource_part_count>: default true
+
+If true, the resource will show a part count B<if> the full
+part list is not displayed. (See "condense_parts" later.) If false,
+the resource will never show a part count.
+
+=item * B<resource_no_folder_link>:
+
+If true, the resource's folder will not be clickable to open or close
+it. Default is false. True implies printCloseAll is false, since you
+can't close or open folders when this is on anyhow.
+
+=back
+
+=item * B<Apache::lonnavmaps::communication_status>:
+
+Whether there is discussion on the resource, email for the user, or
+(lumped in here) perl errors in the execution of the problem. This is
+the second column in the main nav map.
+
+=item * B<Apache::lonnavmaps::quick_status>:
+
+An icon for the status of a problem, with five possible states:
+Correct, incorrect, open, awaiting grading (for a problem where the
+computer's grade is suppressed, or the computer can't grade, like
+essay problem), or none (not open yet, not a problem). The
+third column of the standard navmap.
+
+=item * B<Apache::lonnavmaps::long_status>:
+
+A text readout of the details of the current status of the problem,
+such as "Due in 22 hours". The fourth column of the standard navmap.
+
+=item * B<Apache::lonnavmaps::part_status_summary>:
+
+A text readout summarizing the status of the problem. If it is a
+single part problem, will display "Correct", "Incorrect", 
+"Not yet open", "Open", "Attempted", or "Error". If there are
+multiple parts, this will output a string that in HTML will show a
+status of how many parts are in each status, in color coding, trying
+to match the colors of the icons within reason.
+
+Note this only makes sense if you are I<not> showing parts. If 
+C<showParts> is true (see below), this column will not output
+anything. 
+
+=back
+
+If you add any others please be sure to document them here.
+
+An example of a column renderer that will show the ID number of a
+resource, along with the part name if any:
+
+ sub { 
+  my ($resource, $part, $params) = @_;   
+  if ($part) { return '<td>' . $resource->{ID} . ' ' . $part . '</td>'; }
+  return '<td>' . $resource->{ID} . '</td>';
+ }
+
+Note these functions are responsible for the TD tags, which allow them
+to override vertical and horizontal alignment, etc.
+
+=head2 Parameters
+
+Minimally, you should be
+able to get away with just using 'cols' (to specify the columns
+shown), 'url' (necessary for the folders to link to the current screen
+correctly), and possibly 'queryString' if your app calls for it. In
+that case, maintaining the state of the folders will be done
+automatically.
+
+=over 4
+
+=item * B<iterator>: default: constructs one from %env
+
+A reference to a fresh ::iterator to use from the navmaps. The
+rendering will reflect the options passed to the iterator, so you can
+use that to just render a certain part of the course, if you like. If
+one is not passed, the renderer will attempt to construct one from
+env{'form.filter'} and env{'form.condition'} information, plus the
+'iterator_map' parameter if any.
+
+=item * B<iterator_map>: default: not used
+
+If you are letting the renderer do the iterator handling, you can
+instruct the renderer to render only a particular map by passing it
+the source of the map you want to process, like
+'/res/103/jerf/navmap.course.sequence'.
+
+=item * B<navmap>: default: constructs one from %env
+
+A reference to a navmap, used only if an iterator is not passed in. If
+this is necessary to make an iterator but it is not passed in, a new
+one will be constructed based on env info. This is useful to do basic
+error checking before passing it off to render.
+
+=item * B<r>: default: must be passed in
+
+The standard Apache response object. This must be passed to the
+renderer or the course hash will be locked.
+
+=item * B<cols>: default: empty (useless)
+
+An array reference
+
+=item * B<showParts>:default true
+
+A flag. If true, a line for the resource itself, and a line
+for each part will be displayed. If not, only one line for each
+resource will be displayed.
+
+=item * B<condenseParts>: default true
+
+A flag. If true, if all parts of the problem have the same
+status and that status is Nothing Set, Correct, or Network Failure,
+then only one line will be displayed for that resource anyhow. If no,
+all parts will always be displayed. If showParts is 0, this is
+ignored.
+
+=item * B<jumpCount>: default: determined from %env
+
+A string identifying the URL to place the anchor 'curloc' at.
+It is the responsibility of the renderer user to
+ensure that the #curloc is in the URL. By default, determined through
+the use of the env{} 'jump' information, and should normally "just
+work" correctly.
+
+=item * B<here>: default: empty string
+
+A Symb identifying where to place the 'here' marker. The empty
+string means no marker.
+
+=item * B<indentString>: default: 25 pixel whitespace image
+
+A string identifying the indentation string to use. 
+
+=item * B<queryString>: default: empty
+
+A string which will be prepended to the query string used when the
+folders are opened or closed. You can use this to pass
+application-specific values.
+
+=item * B<url>: default: none
+
+The url the folders will link to, which should be the current
+page. Required if the resource info column is shown, and you 
+are allowing the user to open and close folders.
+
+=item * B<currentJumpIndex>: default: no jumping
+
+Describes the currently-open row number to cause the browser to jump
+to, because the user just opened that folder. By default, pulled from
+the Jump information in the env{'form.*'}.
+
+=item * B<printKey>: default: false
+
+If true, print the key that appears on the top of the standard
+navmaps.
+
+=item * B<printCloseAll>: default: true
+
+If true, print the "Close all folders" or "open all folders"
+links.
+
+=item * B<filterFunc>: default: sub {return 1;} (accept everything)
+
+A function that takes the resource object as its only parameter and
+returns a true or false value. If true, the resource is displayed. If
+false, it is simply skipped in the display.
+
+=item * B<suppressEmptySequences>: default: false
+
+If you're using a filter function, and displaying sequences to orient
+the user, then frequently some sequences will be empty. Setting this to
+true will cause those sequences not to display, so as not to confuse the
+user into thinking that if the sequence is there there should be things
+under it; for example, see the "Show Uncompleted Homework" view on the
+B<NAV> screen.
+
+=item * B<suppressNavmaps>: default: false
+
+If true, will not display Navigate Content resources. 
+
+=back
+
+=head2 Additional Info
+
+In addition to the parameters you can pass to the renderer, which will
+be passed through unchange to the column renderers, the renderer will
+generate the following information which your renderer may find
+useful:
+
+=over 4
+
+=item * B<counter>: 
+
+Contains the number of rows printed. Useful after calling the render 
+function, as you can detect whether anything was printed at all.
+
+=item * B<isNewBranch>:
+
+Useful for renderers: If this resource is currently the first resource
+of a new branch, this will be true. The Resource column (leftmost in the
+navmaps screen) uses this to display the "new branch" icon 
+
+=back
+
+=cut
+
+sub resource { return 0; }
+sub communication_status { return 1; }
+sub quick_status { return 2; }
+sub long_status { return 3; }
+sub part_status_summary { return 4; }
+
+sub render_resource {
+    my ($resource, $part, $params) = @_;
+
+    my $nonLinkedText = ''; # stuff after resource title not in link
+
+    my $link = $params->{"resourceLink"};
+
+    #  The URL part is not escaped at this point, but the symb is... 
+    #  The stuff to the left of the ? must have ' replaced by \' since
+    #  it will be quoted with ' in the href.
+
+    my ($left,$right) = split(/\?/, $link);
+    $link = $left.'?'.$right;
+
+    my $src = $resource->src();
+    my $it = $params->{"iterator"};
+    my $filter = $it->{FILTER};
+
+    my $title = $resource->compTitle();
+
+    my $partLabel = "";
+    my $newBranchText = "";
+    my $location=&Apache::loncommon::lonhttpdurl("/adm/lonIcons");
+    # If this is a new branch, label it so
+    if ($params->{'isNewBranch'}) {
+        $newBranchText = "<img src='$location/branch.gif' border='0' alt='Branch' />";
+    }
+
+    # links to open and close the folder
+
+    
+    my $linkopen = "<a href=\"$link\">";
+
+
+    my $linkclose = "</a>";
+
+    # Default icon: unknown page
+    my $icon = "<img src='$location/unknown.gif' alt='' border='0' alt='&nbsp;&nbsp;' ' />";
+    
+    if ($resource->is_problem()) {
+        if ($part eq '0' || $params->{'condensed'}) {
+            $icon ='<img src="'.$location.'/problem.gif" alt="'.&mt('Problem').'" border="0" />';
+        } else {
+            $icon = $params->{'indentString'};
+        }
+    } else {
+	$icon = "<img src='".&Apache::loncommon::icon($resource->src)."' alt='&nbsp;&nbsp;' border='0' />";
+    }
+
+    # Display the correct map icon to open or shut map
+    if ($resource->is_map()) {
+        my $mapId = $resource->map_pc();
+        my $nowOpen = !defined($filter->{$mapId});
+        if ($it->{CONDITION}) {
+            $nowOpen = !$nowOpen;
+        }
+
+	my $folderType = $resource->is_sequence() ? 'folder' : 'page';
+        my $title=$resource->title;
+        $title=~s/\"/\&quot;/g;
+        if (!$params->{'resource_no_folder_link'}) {
+            $icon = "navmap.$folderType." . ($nowOpen ? 'closed' : 'open') . '.gif';
+	    $icon = "<img src='$location/$icon' alt=\"".
+		($nowOpen ? &mt('Open Folder') : &mt('Close Folder')).' '.$title."\" border='0' />";
+
+            $linkopen = "<a href=\"" . $params->{'url'} . '?' . 
+                $params->{'queryString'} . '&filter=';
+            $linkopen .= ($nowOpen xor $it->{CONDITION}) ?
+                addToFilter($filter, $mapId) :
+                removeFromFilter($filter, $mapId);
+            $linkopen .= "&condition=" . $it->{CONDITION} . '&hereType='
+                . $params->{'hereType'} . '&here=' .
+                &Apache::lonnet::escape($params->{'here'}) . 
+                '&jump=' .
+                &Apache::lonnet::escape($resource->symb()) . 
+                "&folderManip=1\">";
+
+        } else {
+            # Don't allow users to manipulate folder
+            $icon = "navmap.$folderType." . ($nowOpen ? 'closed' : 'open') .
+                '.nomanip.gif';
+            $icon = "<img src='$location/$icon' alt=\"".
+		($nowOpen ? &mt('Open Folder') : &mt('Close Folder')).' '.$title."\" border='0' />";
+
+            $linkopen = "";
+            $linkclose = "";
+        }
+    }
+
+    if ($resource->randomout()) {
+        $nonLinkedText .= ' <i>('.&mt('hidden').')</i> ';
+    }
+    if (!$resource->condval()) {
+        $nonLinkedText .= ' <i>('.&mt('conditionally hidden').')</i> ';
+    }
+    
+    # We're done preparing and finally ready to start the rendering
+    my $result = "<td align='left' valign='center'>";
+
+    my $indentLevel = $params->{'indentLevel'};
+    if ($newBranchText) { $indentLevel--; }
+
+    # print indentation
+    for (my $i = 0; $i < $indentLevel; $i++) {
+        $result .= $params->{'indentString'};
+    }
+
+    # Decide what to display
+
+    $result .= "$newBranchText$linkopen$icon$linkclose";
+    
+    my $curMarkerBegin = '';
+    my $curMarkerEnd = '';
+
+    # Is this the current resource?
+    if (!$params->{'displayedHereMarker'} && 
+        $resource->symb() eq $params->{'here'} ) {
+        $curMarkerBegin = '<font color="red" size="+2">&gt;</font>';
+        $curMarkerEnd = '<font color="red" size="+2">&lt;</font>';
+        $params->{'displayedHereMarker'} = 1;
+    }
+
+    if ($resource->is_problem() && $part ne '0' && 
+        !$params->{'condensed'}) {
+	my $displaypart=$resource->part_display($part);
+        $partLabel = " (".&mt('Part: [_1]', $displaypart).")";
+	if ($link!~/\#/) { $link.='#'.&Apache::lonnet::escape($part); }
+        $title = "";
+    }
+
+    if ($params->{'condensed'} && $resource->countParts() > 1) {
+        $nonLinkedText .= ' ('.&mt('[_1] parts', $resource->countParts()).')';
+    }
+
+    my $target;
+    if ($env{'environment.remotenavmap'} eq 'on') {
+	$target=' target="loncapaclient" ';
+    }
+    if (!$params->{'resource_nolink'} && !$resource->is_sequence() && !$resource->is_empty_sequence) {
+        $result .= "  $curMarkerBegin<a $target href=\"$link\">$title$partLabel</a>$curMarkerEnd $nonLinkedText</td>";
+    } else {
+        $result .= "  $curMarkerBegin$title$partLabel$curMarkerEnd $nonLinkedText</td>";
+    }
+
+    return $result;
+}
+
+sub render_communication_status {
+    my ($resource, $part, $params) = @_;
+    my $discussionHTML = ""; my $feedbackHTML = ""; my $errorHTML = "";
+
+    my $link = $params->{"resourceLink"};
+    my $target;
+    if ($env{'environment.remotenavmap'} eq 'on') {
+	$target=' target="loncapaclient" ';
+    }
+    my $linkopen = "<a $target href=\"$link\">";
+    my $linkclose = "</a>";
+    my $location=&Apache::loncommon::lonhttpdurl("/adm/lonMisc");
+    if ($resource->hasDiscussion()) {
+        $discussionHTML = $linkopen .
+            '<img border="0" src="'.$location.'/chat.gif" />' .
+            $linkclose;
+    }
+    
+    if ($resource->getFeedback()) {
+        my $feedback = $resource->getFeedback();
+        foreach (split(/\,/, $feedback)) {
+            if ($_) {
+                $feedbackHTML .= '&nbsp;<a '.$target.' href="/adm/email?display='
+                    . &Apache::lonnet::escape($_) . '">'
+                    . '<img src="'.$location.'/feedback.gif" '
+                    . 'border="0" /></a>';
+            }
+        }
+    }
+    
+    if ($resource->getErrors()) {
+        my $errors = $resource->getErrors();
+        my $errorcount = 0;
+        foreach (split(/,/, $errors)) {
+            last if ($errorcount>=10); # Only output 10 bombs maximum
+            if ($_) {
+                $errorcount++;
+                $errorHTML .= '&nbsp;<a '.$target.' href="/adm/email?display='
+                    . &Apache::lonnet::escape($_) . '">'
+                    . '<img src="'.$location.'/bomb.gif" '
+                    . 'border="0" /></a>';
+            }
+        }
+    }
+
+    if ($params->{'multipart'} && $part != '0') {
+	$discussionHTML = $feedbackHTML = $errorHTML = '';
+    }
+
+    return "<td width=\"75\" align=\"left\" valign=\"center\">$discussionHTML$feedbackHTML$errorHTML&nbsp;</td>";
+
+}
+sub render_quick_status {
+    my ($resource, $part, $params) = @_;
+    my $result = "";
+    my $firstDisplayed = !$params->{'condensed'} && 
+        $params->{'multipart'} && $part eq "0";
+
+    my $link = $params->{"resourceLink"};
+    my $target;
+    if ($env{'environment.remotenavmap'} eq 'on') {
+	$target=' target="loncapaclient" ';
+    }
+    my $linkopen = "<a $target href=\"$link\">";
+    my $linkclose = "</a>";
+
+    if ($resource->is_problem() &&
+        !$firstDisplayed) {
+	
+        my $icon = $statusIconMap{$resource->simpleStatus($part)};
+        my $alt = $iconAltTags{$icon};
+        if ($icon) {
+	    my $location=
+		&Apache::loncommon::lonhttpdurl("/adm/lonIcons/$icon");
+            $result .= "<td width='30' valign='center' width='50' align='right'>$linkopen<img width='25' height='25' src='$location' border='0' alt='$alt' />$linkclose</td>\n";
+        } else {
+            $result .= "<td width='30'>&nbsp;</td>\n";
+        }
+    } else { # not problem, no icon
+        $result .= "<td width='30'>&nbsp;</td>\n";
+    }
+
+    return $result;
+}
+sub render_long_status {
+    my ($resource, $part, $params) = @_;
+    my $result = "<td align='right' valign='center'>\n";
+    my $firstDisplayed = !$params->{'condensed'} && 
+        $params->{'multipart'} && $part eq "0";
+                
+    my $color;
+    if ($resource->is_problem()) {
+        $color = $colormap{$resource->status};
+        
+        if (dueInLessThan24Hours($resource, $part) ||
+            lastTry($resource, $part)) {
+            $color = $hurryUpColor;
+        }
+    }
+    
+    if ($resource->kind() eq "res" &&
+        $resource->is_problem() &&
+        !$firstDisplayed) {
+        if ($color) {$result .= "<font color=\"$color\"><b>"; }
+        $result .= getDescription($resource, $part);
+        if ($color) {$result .= "</b></font>"; }
+    }
+    if ($resource->is_map() && advancedUser() && $resource->randompick()) {
+        $result .= '(randomly select ' . $resource->randompick() .')';
+    }
+
+    # Debugging code
+    #$result .= " " . $resource->awarded($part) . '/' . $resource->weight($part) .
+    #	' - Part: ' . $part;
+
+    $result .= "</td>\n";
+    
+    return $result;
+}
+
+# Colors obtained by taking the icons, matching the colors, and
+# possibly reducing the Value (HSV) of the color, if it's too bright
+# for text, generally by one third or so.
+my %statusColors = 
+    (
+     $resObj->CLOSED => '#000000',
+     $resObj->OPEN   => '#998b13',
+     $resObj->CORRECT => '#26933f',
+     $resObj->INCORRECT => '#c48207',
+     $resObj->ATTEMPTED => '#a87510',
+     $resObj->ERROR => '#000000'
+     );
+my %statusStrings = 
+    (
+     $resObj->CLOSED => 'Not yet open',
+     $resObj->OPEN   => 'Open',
+     $resObj->CORRECT => 'Correct',
+     $resObj->INCORRECT => 'Incorrect',
+     $resObj->ATTEMPTED => 'Attempted',
+     $resObj->ERROR => 'Network Error'
+     );
+my @statuses = ($resObj->CORRECT, $resObj->ATTEMPTED, $resObj->INCORRECT, $resObj->OPEN, $resObj->CLOSED, $resObj->ERROR);
+
+use Data::Dumper;
+sub render_parts_summary_status {
+    my ($resource, $part, $params) = @_;
+    if (!$resource->is_problem() && !$resource->contains_problem) { return '<td></td>'; }
+    if ($params->{showParts}) { 
+	return '<td></td>';
+    }
+
+    my $td = "<td align='right'>\n";
+    my $endtd = "</td>\n";
+    my @probs;
+
+    if ($resource->contains_problem) {
+	@probs=$resource->retrieveResources($resource,sub { $_[0]->is_problem() },1,0);
+    } else {
+	@probs=($resource);
+    }
+    my $return;
+    my %overallstatus;
+    my $totalParts;
+    foreach my $resource (@probs) {
+	# If there is a single part, just show the simple status
+	if ($resource->singlepart()) {
+	    my $status = $resource->simpleStatus(${$resource->parts}[0]);
+	    $overallstatus{$status}++;
+	    $totalParts++;
+	    next;
+	}
+	# Now we can be sure the $part doesn't really matter.
+	my $statusCount = $resource->simpleStatusCount();
+	my @counts;
+	foreach my $status (@statuses) {
+	    # decouple display order from the simpleStatusCount order
+	    my $slot = Apache::lonnavmaps::resource::statusToSlot($status);
+	    if ($statusCount->[$slot]) {
+		$overallstatus{$status}+=$statusCount->[$slot];
+		$totalParts+=$statusCount->[$slot];
+	    }
+	}
+    }
+    $return.= $td . $totalParts . ' parts: ';
+    foreach my $status (@statuses) {
+	if ($overallstatus{$status}) {
+	    $return.="<font color='" . $statusColors{$status} .
+		"'>" . $overallstatus{$status} . ' '
+		. $statusStrings{$status} . "</font>";
+	}
+    }
+    $return.= $endtd;
+    return $return;
+}
+
+my @preparedColumns = (\&render_resource, \&render_communication_status,
+                       \&render_quick_status, \&render_long_status,
+		       \&render_parts_summary_status);
+
+sub setDefault {
+    my ($val, $default) = @_;
+    if (!defined($val)) { return $default; }
+    return $val;
+}
+
+sub cmp_title {
+    my ($atitle,$btitle) = (lc($_[0]->compTitle),lc($_[1]->compTitle));
+    $atitle=~s/^\s*//;
+    $btitle=~s/^\s*//;
+    return $atitle cmp $btitle;
+}
+
+sub render {
+    my $args = shift;
+    &Apache::loncommon::get_unprocessed_cgi($ENV{QUERY_STRING});
+    my $result = '';
+    # Configure the renderer.
+    my $cols = $args->{'cols'};
+    if (!defined($cols)) {
+        # no columns, no nav maps.
+        return '';
+    }
+    my $navmap;
+    if (defined($args->{'navmap'})) {
+        $navmap = $args->{'navmap'};
+    }
+
+    my $r = $args->{'r'};
+    my $queryString = $args->{'queryString'};
+    my $jump = $args->{'jump'};
+    my $here = $args->{'here'};
+    my $suppressNavmap = setDefault($args->{'suppressNavmap'}, 0);
+    my $closeAllPages = setDefault($args->{'closeAllPages'}, 0);
+    my $currentJumpDelta = 2; # change this to change how many resources are displayed
+                             # before the current resource when using #current
+
+    # If we were passed 'here' information, we are not rendering
+    # after a folder manipulation, and we were not passed an
+    # iterator, make sure we open the folders to show the "here"
+    # marker
+    my $filterHash = {};
+    # Figure out what we're not displaying
+    foreach (split(/\,/, $env{"form.filter"})) {
+        if ($_) {
+            $filterHash->{$_} = "1";
+        }
+    }
+
+    # Filter: Remember filter function and add our own filter: Refuse
+    # to show hidden resources unless the user can see them.
+    my $userCanSeeHidden = advancedUser();
+    my $filterFunc = setDefault($args->{'filterFunc'},
+                                sub {return 1;});
+    if (!$userCanSeeHidden) {
+        # Without renaming the filterfunc, the server seems to go into
+        # an infinite loop
+        my $oldFilterFunc = $filterFunc;
+        $filterFunc = sub { my $res = shift; return !$res->randomout() && 
+                                &$oldFilterFunc($res);};
+    }
+
+    my $condition = 0;
+    if ($env{'form.condition'}) {
+        $condition = 1;
+    }
+
+    if (!$env{'form.folderManip'} && !defined($args->{'iterator'})) {
+        # Step 1: Check to see if we have a navmap
+        if (!defined($navmap)) {
+            $navmap = Apache::lonnavmaps::navmap->new();
+	    if (!defined($navmap)) {
+		# no londer in course
+		return '<font color="red">'.&mt('No course selected').'</font><br />
+                        <a href="/adm/roles">'.&mt('Select a course').'</a><br />';
+	    }
+	}
+
+        # Step two: Locate what kind of here marker is necessary
+        # Determine where the "here" marker is and where the screen jumps to.
+
+        if ($env{'form.postsymb'} ne '') {
+            $here = $jump = &Apache::lonnet::symbclean($env{'form.postsymb'});
+        } elsif ($env{'form.postdata'} ne '') {
+            # couldn't find a symb, is there a URL?
+            my $currenturl = $env{'form.postdata'};
+            #$currenturl=~s/^http\:\/\///;
+            #$currenturl=~s/^[^\/]+//;
+            
+            $here = $jump = &Apache::lonnet::symbread($currenturl);
+	}
+	if ($here eq '') {
+	    my $last;
+	    if (tie(my %hash,'GDBM_File',$env{'request.course.fn'}.'_symb.db',
+                    &GDBM_READER(),0640)) {
+		$last=$hash{'last_known'};
+		untie(%hash);
+	    }
+	    if ($last) { $here = $jump = $last; }
+	}
+
+        # Step three: Ensure the folders are open
+        my $mapIterator = $navmap->getIterator(undef, undef, undef, 1);
+        my $curRes;
+        my $found = 0;
+        
+        # We only need to do this if we need to open the maps to show the
+        # current position. This will change the counter so we can't count
+        # for the jump marker with this loop.
+        while ($here && ($curRes = $mapIterator->next()) && !$found) {
+            if (ref($curRes) && $curRes->symb() eq $here) {
+                my $mapStack = $mapIterator->getStack();
+                
+                # Ensure the parent maps are open
+                for my $map (@{$mapStack}) {
+                    if ($condition) {
+                        undef $filterHash->{$map->map_pc()};
+                    } else {
+                        $filterHash->{$map->map_pc()} = 1;
+                    }
+                }
+                $found = 1;
+            }
+        }            
+    }        
+
+    if ( !defined($args->{'iterator'}) && $env{'form.folderManip'} ) { # we came from a user's manipulation of the nav page
+        # If this is a click on a folder or something, we want to preserve the "here"
+        # from the querystring, and get the new "jump" marker
+        $here = $env{'form.here'};
+        $jump = $env{'form.jump'};
+    } 
+    
+    my $it = $args->{'iterator'};
+    if (!defined($it)) {
+        # Construct a default iterator based on $env{'form.'} information
+        
+        # Step 1: Check to see if we have a navmap
+        if (!defined($navmap)) {
+            $navmap = Apache::lonnavmaps::navmap->new();
+        }
+
+        # See if we're being passed a specific map
+        if ($args->{'iterator_map'}) {
+            my $map = $args->{'iterator_map'};
+            $map = $navmap->getResourceByUrl($map);
+            my $firstResource = $map->map_start();
+            my $finishResource = $map->map_finish();
+
+            $args->{'iterator'} = $it = $navmap->getIterator($firstResource, $finishResource, $filterHash, $condition);
+        } else {
+            $args->{'iterator'} = $it = $navmap->getIterator(undef, undef, $filterHash, $condition);
+        }
+    }
+
+    # (re-)Locate the jump point, if any
+    # Note this does not take filtering or hidden into account... need
+    # to be fixed?
+    my $mapIterator = $navmap->getIterator(undef, undef, $filterHash, 0);
+    my $curRes;
+    my $foundJump = 0;
+    my $counter = 0;
+    
+    while (($curRes = $mapIterator->next()) && !$foundJump) {
+        if (ref($curRes)) { $counter++; }
+        
+        if (ref($curRes) && $jump eq $curRes->symb()) {
+            
+            # This is why we have to use the main iterator instead of the
+            # potentially faster DFS: The count has to be the same, so
+            # the order has to be the same, which DFS won't give us.
+            $args->{'currentJumpIndex'} = $counter;
+            $foundJump = 1;
+        }
+    }
+
+    my $showParts = setDefault($args->{'showParts'}, 1);
+    my $condenseParts = setDefault($args->{'condenseParts'}, 1);
+    # keeps track of when the current resource is found,
+    # so we can back up a few and put the anchor above the
+    # current resource
+    my $printKey = $args->{'printKey'};
+    my $printCloseAll = $args->{'printCloseAll'};
+    if (!defined($printCloseAll)) { $printCloseAll = 1; }
+
+    # Print key?
+    if ($printKey) {
+        $result .= '<table border="0" cellpadding="2" cellspacing="0">';
+        my $date=localtime;
+        $result.='<tr><td align="right" valign="bottom">Key:&nbsp;&nbsp;</td>';
+	my $location=&Apache::loncommon::lonhttpdurl("/adm/lonMisc");
+        if ($navmap->{LAST_CHECK}) {
+            $result .= 
+                '<img src="'.$location.'/chat.gif"> '.&mt('New discussion since').' '.
+                strftime("%A, %b %e at %I:%M %P", localtime($navmap->{LAST_CHECK})).
+                '</td><td align="center" valign="bottom">&nbsp;&nbsp;'.
+                '<img src="'.$location.'/feedback.gif"> '.&mt('New message (click to open)').'<p>'.
+                '</td>'; 
+        } else {
+            $result .= '<td align="center" valign="bottom">&nbsp;&nbsp;'.
+                '<img src="'.$location.'/chat.gif"> '.&mt('Discussions').'</td><td align="center" valign="bottom">'.
+                '&nbsp;&nbsp;<img src="'.$location.'/feedback.gif"> '.&mt('New message (click to open)').
+                '</td>'; 
+        }
+
+        $result .= '</tr></table>';
+    }
+
+    if ($printCloseAll && !$args->{'resource_no_folder_link'}) {
+	my ($link,$text);
+        if ($condition) {
+	    $link='"navmaps?condition=0&filter=&'.$queryString.
+		'&here='.&Apache::lonnet::escape($here).'"';
+	    $text='Close All Folders';
+        } else {
+	    $link='"navmaps?condition=1&filter=&'.$queryString.
+		'&here='.&Apache::lonnet::escape($here).'"';
+	    $text='Open All Folders';
+        }
+	if ($args->{'caller'} eq 'navmapsdisplay') {
+	    &add_linkitem($args->{'linkitems'},'changefolder',
+			  'location.href='.$link,$text);
+	} else {
+	    $result.='<a href='.$link.'>'.&mt($text).'</a>';
+	}
+        $result .= "\n";
+    }
+
+    # Check for any unread discussions in all resources.
+    if ($args->{'caller'} eq 'navmapsdisplay') {
+	&add_linkitem($args->{'linkitems'},'clearbubbles',
+		      'document.clearbubbles.submit()',
+		      'Mark all posts read');
+	my $time=time;
+	$result .= (<<END);
+    <form name="clearbubbles" method="post" action="/adm/feedback">
+	<input type="hidden" name="navurl" value="$ENV{'QUERY_STRING'}" />
+	<input type="hidden" name="navtime" value="$time" />
+END
+        if ($args->{'sort'} eq 'discussion') { 
+	    my $totdisc = 0;
+	    my $haveDisc = '';
+	    my @allres=$navmap->retrieveResources();
+	    foreach my $resource (@allres) {
+		if ($resource->hasDiscussion()) {
+		    $haveDisc .= $resource->wrap_symb().':';
+		    $totdisc ++;
+		}
+	    }
+	    if ($totdisc > 0) {
+		$haveDisc =~ s/:$//;
+		$result .= (<<END);
+	<input type="hidden" name="navmaps" value="$haveDisc" />
+    </form>
+END
+            }
+	}
+	$result.='</form>';
+    }
+
+    if ($args->{'caller'} eq 'navmapsdisplay') {
+        $result .= '<table><tr><td>'.
+                   &Apache::loncommon::help_open_menu('','Navigation Screen','Navigation_Screen','',undef,'RAT').'</td>';
+	if ($env{'environment.remotenavmap'} ne 'on') {
+	    $result .= '<td>&nbsp;</td>'; 
+        } else {
+	    $result .= '</tr><tr>'; 
+        }
+	$result.=&show_linkitems($args->{'linkitems'});
+        if ($args->{'sort_html'}) {
+	    if ($env{'environment.remotenavmap'} ne 'on') {
+		$result.='<td>&nbsp;</td><td>&nbsp;</td><td>&nbsp;</td>'.
+		    '<td align="right">'.$args->{'sort_html'}.'</td></tr>';
+	    } else {
+		$result.='</tr><tr><td align="left"><br />'.
+		    $args->{'sort_html'}.'</td></tr>';
+	    }
+	}
+        $result .= '</table>';
+    } elsif ($args->{'sort_html'}) { 
+        $result.=$args->{'sort_html'}; 
+    }
+
+    $result .= "<br />\n";
+    if ($r) {
+        $r->print($result);
+        $r->rflush();
+        $result = "";
+    }
+    # End parameter setting
+            
+    # Data
+    $result .= '<table cellspacing="0" cellpadding="3" border="0" bgcolor="#FFFFFF">' ."\n";
+    my $res = "Apache::lonnavmaps::resource";
+    my %condenseStatuses =
+        ( $res->NETWORK_FAILURE    => 1,
+          $res->NOTHING_SET        => 1,
+          $res->CORRECT            => 1 );
+    my @backgroundColors = ("#FFFFFF", "#F6F6F6");
+
+    # Shared variables
+    $args->{'counter'} = 0; # counts the rows
+    $args->{'indentLevel'} = 0;
+    $args->{'isNewBranch'} = 0;
+    $args->{'condensed'} = 0;    
+    my $location=
+	&Apache::loncommon::lonhttpdurl("/adm/lonIcons/whitespace1.gif");
+    $args->{'indentString'} = setDefault($args->{'indentString'}, "<img src='$location' width='25' height='1' alt='&nbsp;&nbsp;' border='0' />");
+    $args->{'displayedHereMarker'} = 0;
+
+    # If we're suppressing empty sequences, look for them here. Use DFS for speed,
+    # since structure actually doesn't matter, except what map has what resources.
+    if ($args->{'suppressEmptySequences'}) {
+        my $dfsit = Apache::lonnavmaps::DFSiterator->new($navmap,
+                                                         $it->{FIRST_RESOURCE},
+                                                         $it->{FINISH_RESOURCE},
+                                                         {}, undef, 1);
+        my $depth = 0;
+        $dfsit->next();
+        my $curRes = $dfsit->next();
+        while ($depth > -1) {
+            if ($curRes == $dfsit->BEGIN_MAP()) { $depth++; }
+            if ($curRes == $dfsit->END_MAP()) { $depth--; }
+
+            if (ref($curRes)) { 
+                # Parallel pre-processing: Do sequences have non-filtered-out children?
+                if ($curRes->is_map()) {
+                    $curRes->{DATA}->{HAS_VISIBLE_CHILDREN} = 0;
+                    # Sequences themselves do not count as visible children,
+                    # unless those sequences also have visible children.
+                    # This means if a sequence appears, there's a "promise"
+                    # that there's something under it if you open it, somewhere.
+                } else {
+                    # Not a sequence: if it's filtered, ignore it, otherwise
+                    # rise up the stack and mark the sequences as having children
+                    if (&$filterFunc($curRes)) {
+                        for my $sequence (@{$dfsit->getStack()}) {
+                            $sequence->{DATA}->{HAS_VISIBLE_CHILDREN} = 1;
+                        }
+                    }
+                }
+            }
+        } continue {
+            $curRes = $dfsit->next();
+        }
+    }
+
+    my $displayedJumpMarker = 0;
+    # Set up iteration.
+    my $now = time();
+    my $in24Hours = $now + 24 * 60 * 60;
+    my $rownum = 0;
+
+    # export "here" marker information
+    $args->{'here'} = $here;
+
+    $args->{'indentLevel'} = -1; # first BEGIN_MAP takes this to 0
+    my @resources;
+    my $code='';# sub { !(shift->is_map();) };
+    if ($args->{'sort'} eq 'title') {
+        my $oldFilterFunc = $filterFunc;
+	my $filterFunc= 
+	    sub {
+		my ($res)=@_;
+		if ($res->is_map()) { return 0;}
+		return &$oldFilterFunc($res);
+	    };
+	@resources=$navmap->retrieveResources(undef,$filterFunc);
+	@resources= sort { &cmp_title($a,$b) } @resources;
+    } elsif ($args->{'sort'} eq 'duedate') {
+	my $oldFilterFunc = $filterFunc;
+	my $filterFunc= 
+	    sub {
+		my ($res)=@_;
+		if (!$res->is_problem()) { return 0;}
+		return &$oldFilterFunc($res);
+	    };
+	@resources=$navmap->retrieveResources(undef,$filterFunc);
+	@resources= sort {
+	    if ($a->duedate ne $b->duedate) {
+	        return $a->duedate cmp $b->duedate;
+	    }
+	    my $value=&cmp_title($a,$b);
+	    return $value;
+	} @resources;
+    } elsif ($args->{'sort'} eq 'discussion') {
+	my $oldFilterFunc = $filterFunc;
+	my $filterFunc= 
+	    sub {
+		my ($res)=@_;
+		if (!$res->hasDiscussion() &&
+		    !$res->getFeedback() &&
+		    !$res->getErrors()) { return 0;}
+		return &$oldFilterFunc($res);
+	    };
+	@resources=$navmap->retrieveResources(undef,$filterFunc);
+	@resources= sort { &cmp_title($a,$b) } @resources;
+    } else {
+	#unknow sort mechanism or default
+	undef($args->{'sort'});
+    }
+
+
+    while (1) {
+	if ($args->{'sort'}) {
+	    $curRes = shift(@resources);
+	} else {
+	    $curRes = $it->next($closeAllPages);
+	}
+	if (!$curRes) { last; }
+
+        # Maintain indentation level.
+        if ($curRes == $it->BEGIN_MAP() ||
+            $curRes == $it->BEGIN_BRANCH() ) {
+            $args->{'indentLevel'}++;
+        }
+        if ($curRes == $it->END_MAP() ||
+            $curRes == $it->END_BRANCH() ) {
+            $args->{'indentLevel'}--;
+        }
+        # Notice new branches
+        if ($curRes == $it->BEGIN_BRANCH()) {
+            $args->{'isNewBranch'} = 1;
+        }
+
+        # If this isn't an actual resource, continue on
+        if (!ref($curRes)) {
+            next;
+        }
+
+        # If this has been filtered out, continue on
+        if (!(&$filterFunc($curRes))) {
+            $args->{'isNewBranch'} = 0; # Don't falsely remember this
+            next;
+        } 
+
+        # If this is an empty sequence and we're filtering them, continue on
+        if ($curRes->is_map() && $args->{'suppressEmptySequences'} &&
+            !$curRes->{DATA}->{HAS_VISIBLE_CHILDREN}) {
+            next;
+        }
+
+        # If we're suppressing navmaps and this is a navmap, continue on
+        if ($suppressNavmap && $curRes->src() =~ /^\/adm\/navmaps/) {
+            next;
+        }
+
+        $args->{'counter'}++;
+
+        # Does it have multiple parts?
+        $args->{'multipart'} = 0;
+        $args->{'condensed'} = 0;
+        my @parts;
+            
+        # Decide what parts to show.
+        if ($curRes->is_problem() && $showParts) {
+            @parts = @{$curRes->parts()};
+            $args->{'multipart'} = $curRes->multipart();
+            
+            if ($condenseParts) { # do the condensation
+                if (!$args->{'condensed'}) {
+                    # Decide whether to condense based on similarity
+                    my $status = $curRes->status($parts[0]);
+                    my $due = $curRes->duedate($parts[0]);
+                    my $open = $curRes->opendate($parts[0]);
+                    my $statusAllSame = 1;
+                    my $dueAllSame = 1;
+                    my $openAllSame = 1;
+                    for (my $i = 1; $i < scalar(@parts); $i++) {
+                        if ($curRes->status($parts[$i]) != $status){
+                            $statusAllSame = 0;
+                        }
+                        if ($curRes->duedate($parts[$i]) != $due ) {
+                            $dueAllSame = 0;
+                        }
+                        if ($curRes->opendate($parts[$i]) != $open) {
+                            $openAllSame = 0;
+                        }
+                    }
+                    # $*allSame is true if all the statuses were
+                    # the same. Now, if they are all the same and
+                    # match one of the statuses to condense, or they
+                    # are all open with the same due date, or they are
+                    # all OPEN_LATER with the same open date, display the
+                    # status of the first non-zero part (to get the 'correct'
+                    # status right, since 0 is never 'correct' or 'open').
+                    if (($statusAllSame && defined($condenseStatuses{$status})) ||
+                        ($dueAllSame && $status == $curRes->OPEN && $statusAllSame)||
+                        ($openAllSame && $status == $curRes->OPEN_LATER && $statusAllSame) ){
+                        @parts = ($parts[0]);
+                        $args->{'condensed'} = 1;
+                    }
+                }
+		# Multipart problem with one part: always "condense" (happens
+		#  to match the desirable behavior)
+		if ($curRes->countParts() == 1) {
+		    @parts = ($parts[0]);
+		    $args->{'condensed'} = 1;
+		}
+            }
+        } 
+            
+        # If the multipart problem was condensed, "forget" it was multipart
+        if (scalar(@parts) == 1) {
+            $args->{'multipart'} = 0;
+        } else {
+            # Add part 0 so we display it correctly.
+            unshift @parts, '0';
+        }
+	
+	{
+	    my ($src,$symb,$anchor,$stack);
+	    if ($args->{'sort'}) {
+		my $it = $navmap->getIterator(undef, undef, undef, 1);
+		while ( my $res=$it->next()) {
+		    if (ref($res) &&
+			$res->symb() eq  $curRes->symb()) { last; }
+		}
+		$stack=$it->getStack();
+	    } else {
+		$stack=$it->getStack();
+	    }
+	    ($src,$symb,$anchor)=getLinkForResource($stack);
+	    if (defined($anchor)) { $anchor='#'.$anchor; }
+	    my $srcHasQuestion = $src =~ /\?/;
+	    $args->{"resourceLink"} = $src.
+		($srcHasQuestion?'&':'?') .
+		'symb=' . &Apache::lonnet::escape($symb).$anchor;
+	}
+        # Now, we've decided what parts to show. Loop through them and
+        # show them.
+        foreach my $part (@parts) {
+            $rownum ++;
+            my $backgroundColor = $backgroundColors[$rownum % scalar(@backgroundColors)];
+            
+            $result .= "  <tr bgcolor='$backgroundColor'>\n";
+
+            # Set up some data about the parts that the cols might want
+            my $filter = $it->{FILTER};
+
+            # Now, display each column.
+            foreach my $col (@$cols) {
+                my $colHTML = '';
+                if (ref($col)) {
+                    $colHTML .= &$col($curRes, $part, $args);
+                } else {
+                    $colHTML .= &{$preparedColumns[$col]}($curRes, $part, $args);
+                }
+
+                # If this is the first column and it's time to print
+                # the anchor, do so
+                if ($col == $cols->[0] && 
+                    $args->{'counter'} == $args->{'currentJumpIndex'} - 
+                    $currentJumpDelta) {
+                    # Jam the anchor after the <td> tag;
+                    # necessary for valid HTML (which Mozilla requires)
+                    $colHTML =~ s/\>/\>\<a name="curloc" \/\>/;
+                    $displayedJumpMarker = 1;
+                }
+                $result .= $colHTML . "\n";
+            }
+            $result .= "    </tr>\n";
+            $args->{'isNewBranch'} = 0;
+        }
+
+        if ($r && $rownum % 20 == 0) {
+            $r->print($result);
+            $result = "";
+            $r->rflush();
+        }
+    } continue {
+	if ($r) {
+	    # If we have the connection, make sure the user is still connected
+	    my $c = $r->connection;
+	    if ($c->aborted()) {
+		# Who cares what we do, nobody will see it anyhow.
+		return '';
+	    }
+	}
+    }
+    
+    # Print out the part that jumps to #curloc if it exists
+    # delay needed because the browser is processing the jump before
+    # it finishes rendering, so it goes to the wrong place!
+    # onload might be better, but this routine has no access to that.
+    # On mozilla, the 0-millisecond timeout seems to prevent this;
+    # it's quite likely this might fix other browsers, too, and 
+    # certainly won't hurt anything.
+    if ($displayedJumpMarker) {
+        $result .= "
+<script>
+if (location.href.indexOf('#curloc')==-1) {
+    setTimeout(\"location += '#curloc';\", 0)
+}
+</script>";
+    }
+
+    $result .= "</table>";
+    
+    if ($r) {
+        $r->print($result);
+        $result = "";
+        $r->rflush();
+    }
+        
+    return $result;
+}
+
+sub add_linkitem {
+    my ($linkitems,$name,$cmd,$text)=@_;
+    $$linkitems{$name}{'cmd'}=$cmd;
+    $$linkitems{$name}{'text'}=&mt($text);
+}
+
+sub show_linkitems {
+    my ($linkitems)=@_;
+    my @linkorder = ("blank","launchnav","closenav","firsthomework",
+		     "everything","uncompleted","changefolder","clearbubbles");
+    
+    my $result .= (<<ENDBLOCK);
+              <td align="left">
+<script type="text/javascript">
+    function changeNavDisplay () {
+	var navchoice = document.linkitems.toplink[document.linkitems.toplink.selectedIndex].value;
+ENDBLOCK
+    foreach my $link (@linkorder) {
+	$result.= "if (navchoice == '$link') {".
+	    $linkitems->{$link}{'cmd'}."}\n";
+    }
+    $result.='}
+              </script>
+                   <form name="linkitems" method="post">
+                       <nobr><select name="toplink">'."\n";
+    foreach my $link (@linkorder) {
+	if (defined($linkitems->{$link})) {
+	    if ($linkitems->{$link}{'text'} ne '') {
+		$result .= ' <option value="'.$link.'">'.
+		    $linkitems->{$link}{'text'}."</option>\n";
+	    }
+	}
+    }
+    $result .= '</select>&nbsp;<input type="button" name="chgnav"
+                   value="Go" onClick="javascript:changeNavDisplay()" />
+                </nobr></form></td>'."\n";
+	
+    return $result;
+}
+
+1;
+
+package Apache::lonnavmaps::navmap;
+
+=pod
+
+=head1 Object: Apache::lonnavmaps::navmap
+
+=head2 Overview
+
+The navmap object's job is to provide access to the resources
+in the course as Apache::lonnavmaps::resource objects, and to
+query and manage the relationship between those resource objects.
+
+Generally, you'll use the navmap object in one of three basic ways.
+In order of increasing complexity and power:
+
+=over 4
+
+=item * C<$navmap-E<gt>getByX>, where X is B<Id>, B<Symb> or B<MapPc> and getResourceByUrl. This provides
+    various ways to obtain resource objects, based on various identifiers.
+    Use this when you want to request information about one object or 
+    a handful of resources you already know the identities of, from some
+    other source. For more about Ids, Symbs, and MapPcs, see the
+    Resource documentation. Note that Url should be a B<last resort>,
+    not your first choice; it only really works when there is only one
+    instance of the resource in the course, which only applies to
+    maps, and even that may change in the future (see the B<getResourceByUrl>
+    documentation for more details.)
+
+=item * C<my @resources = $navmap-E<gt>retrieveResources(args)>. This
+    retrieves resources matching some criterion and returns them
+    in a flat array, with no structure information. Use this when
+    you are manipulating a series of resources, based on what map
+    the are in, but do not care about branching, or exactly how
+    the maps and resources are related. This is the most common case.
+
+=item * C<$it = $navmap-E<gt>getIterator(args)>. This allows you traverse
+    the course's navmap in various ways without writing the traversal
+    code yourself. See iterator documentation below. Use this when
+    you need to know absolutely everything about the course, including
+    branches and the precise relationship between maps and resources.
+
+=back
+
+=head2 Creation And Destruction
+
+To create a navmap object, use the following function:
+
+=over 4
+
+=item * B<Apache::lonnavmaps::navmap-E<gt>new>():
+
+Creates a new navmap object. Returns the navmap object if this is
+successful, or B<undef> if not.
+
+=back
+
+=head2 Methods
+
+=over 4
+
+=item * B<getIterator>(first, finish, filter, condition):
+
+See iterator documentation below.
+
+=cut
+
+use strict;
+use GDBM_File;
+use Apache::lonnet;
+
+sub new {
+    # magic invocation to create a class instance
+    my $proto = shift;
+    my $class = ref($proto) || $proto;
+    my $self = {};
+
+    # Resource cache stores navmap resources as we reference them. We generate
+    # them on-demand so we don't pay for creating resources unless we use them.
+    $self->{RESOURCE_CACHE} = {};
+
+    # Network failure flag, if we accessed the course or user opt and
+    # failed
+    $self->{NETWORK_FAILURE} = 0;
+
+    # tie the nav hash
+
+    my %navmaphash;
+    my %parmhash;
+    my $courseFn = $env{"request.course.fn"};
+    if (!(tie(%navmaphash, 'GDBM_File', "${courseFn}.db",
+              &GDBM_READER(), 0640))) {
+        return undef;
+    }
+    
+    if (!(tie(%parmhash, 'GDBM_File', "${courseFn}_parms.db",
+              &GDBM_READER(), 0640)))
+    {
+        untie %{$self->{PARM_HASH}};
+        return undef;
+    }
+
+    $self->{NAV_HASH} = \%navmaphash;
+    $self->{PARM_HASH} = \%parmhash;
+    $self->{PARM_CACHE} = {};
+
+    bless($self);
+        
+    return $self;
+}
+
+sub generate_course_user_opt {
+    my $self = shift;
+    if ($self->{COURSE_USER_OPT_GENERATED}) { return; }
+
+    my $uname=$env{'user.name'};
+    my $udom=$env{'user.domain'};
+    my $cid=$env{'request.course.id'};
+    my $cdom=$env{'course.'.$cid.'.domain'};
+    my $cnum=$env{'course.'.$cid.'.num'};
+    
+# ------------------------------------------------- Get coursedata (if present)
+    my $courseopt=&Apache::lonnet::get_courseresdata($cnum,$cdom);
+    # Check for network failure
+    if (!ref($courseopt)) {
+	if ( $courseopt =~ /no.such.host/i || $courseopt =~ /con_lost/i) {
+	    $self->{NETWORK_FAILURE} = 1;
+	}
+	undef($courseopt);
+    }
+
+# --------------------------------------------------- Get userdata (if present)
+	
+    my $useropt=&Apache::lonnet::get_userresdata($uname,$udom);
+    # Check for network failure
+    if (!ref($useropt)) {
+	if ( $useropt =~ /no.such.host/i || $useropt =~ /con_lost/i) {
+	    $self->{NETWORK_FAILURE} = 1;
+	}
+	undef($useropt);
+    }
+
+    $self->{COURSE_OPT} = $courseopt;
+    $self->{USER_OPT} = $useropt;
+
+    $self->{COURSE_USER_OPT_GENERATED} = 1;
+    
+    return;
+}
+
+sub generate_email_discuss_status {
+    my $self = shift;
+    my $symb = shift;
+    if ($self->{EMAIL_DISCUSS_GENERATED}) { return; }
+
+    my $cid=$env{'request.course.id'};
+    my $cdom=$env{'course.'.$cid.'.domain'};
+    my $cnum=$env{'course.'.$cid.'.num'};
+    
+    my %emailstatus = &Apache::lonnet::dump('email_status');
+    my $logoutTime = $emailstatus{'logout'};
+    my $courseLeaveTime = $emailstatus{'logout_'.$env{'request.course.id'}};
+    $self->{LAST_CHECK} = (($courseLeaveTime > $logoutTime) ?
+			   $courseLeaveTime : $logoutTime);
+    my %discussiontime = &Apache::lonnet::dump('discussiontimes', 
+					       $cdom, $cnum);
+    my %lastread = &Apache::lonnet::dump('nohist_'.$cid.'_discuss',
+                                        $env{'user.domain'},$env{'user.name'},'lastread');
+    my %lastreadtime = ();
+    foreach (keys %lastread) {
+        my $key = $_;
+        $key =~ s/_lastread$//;
+        $lastreadtime{$key} = $lastread{$_};
+    }
+
+    my %feedback=();
+    my %error=();
+    my @keys = &Apache::lonnet::getkeys('nohist_email',$env{'user.domain'},
+					$env{'user.name'});
+    
+    foreach my $msgid (@keys) {
+	if ((!$emailstatus{$msgid}) || ($emailstatus{$msgid} eq 'new')) {
+	    my $plain=
+		&Apache::lonnet::unescape(&Apache::lonnet::unescape($msgid));
+	    if ($plain=~/ \[([^\]]+)\]\:/) {
+		my $url=$1;
+		if ($plain=~/\:Error \[/) {
+		    $error{$url}.=','.$msgid; 
+		} else {
+		    $feedback{$url}.=','.$msgid;
+		}
+	    }
+	}
+    }
+    
+    #url's of resources that have feedbacks
+    $self->{FEEDBACK} = \%feedback;
+    #or errors
+    $self->{ERROR_MSG} = \%error;
+    $self->{DISCUSSION_TIME} = \%discussiontime;
+    $self->{EMAIL_STATUS} = \%emailstatus;
+    $self->{LAST_READ} = \%lastreadtime;
+    
+    $self->{EMAIL_DISCUSS_GENERATED} = 1;
+}
+
+sub get_user_data {
+    my $self = shift;
+    if ($self->{RETRIEVED_USER_DATA}) { return; }
+
+    # Retrieve performance data on problems
+    my %student_data = Apache::lonnet::currentdump($env{'request.course.id'},
+						   $env{'user.domain'},
+						   $env{'user.name'});
+    $self->{STUDENT_DATA} = \%student_data;
+
+    $self->{RETRIEVED_USER_DATA} = 1;
+}
+
+sub get_discussion_data {
+    my $self = shift;
+    if ($self->{RETRIEVED_DISCUSSION_DATA}) {
+	return $self->{DISCUSSION_DATA};
+    }
+
+    $self->generate_email_discuss_status();    
+
+    my $cid=$env{'request.course.id'};
+    my $cdom=$env{'course.'.$cid.'.domain'};
+    my $cnum=$env{'course.'.$cid.'.num'};
+    # Retrieve discussion data for resources in course
+    my %discussion_data = &Apache::lonnet::dumpstore($cid,$cdom,$cnum);
+
+
+    $self->{DISCUSSION_DATA} = \%discussion_data;
+    $self->{RETRIEVED_DISCUSSION_DATA} = 1;
+    return $self->{DISCUSSION_DATA};
+}
+
+
+# Internal function: Takes a key to look up in the nav hash and implements internal
+# memory caching of that key.
+sub navhash {
+    my $self = shift; my $key = shift;
+    return $self->{NAV_HASH}->{$key};
+}
+
+=pod
+
+=item * B<courseMapDefined>(): Returns true if the course map is defined, 
+    false otherwise. Undefined course maps indicate an error somewhere in
+    LON-CAPA, and you will not be able to proceed with using the navmap.
+    See the B<NAV> screen for an example of using this.
+
+=cut
+
+# Checks to see if coursemap is defined, matching test in old lonnavmaps
+sub courseMapDefined {
+    my $self = shift;
+    my $uri = &Apache::lonnet::clutter($env{'request.course.uri'});
+
+    my $firstres = $self->navhash("map_start_$uri");
+    my $lastres = $self->navhash("map_finish_$uri");
+    return $firstres && $lastres;
+}
+
+sub getIterator {
+    my $self = shift;
+    my $iterator = Apache::lonnavmaps::iterator->new($self, shift, shift,
+                                                     shift, undef, shift,
+						     shift, shift);
+    return $iterator;
+}
+
+# Private method: Does the given resource (as a symb string) have
+# current discussion? Returns 0 if chat/mail data not extracted.
+sub hasDiscussion {
+    my $self = shift;
+    my $symb = shift;
+    $self->generate_email_discuss_status();
+
+    if (!defined($self->{DISCUSSION_TIME})) { return 0; }
+
+    #return defined($self->{DISCUSSION_TIME}->{$symb});
+
+    # backward compatibility (bulletin boards used to be 'wrapped')
+    my $ressymb = $self->wrap_symb($symb);
+    if ( defined ( $self->{LAST_READ}->{$ressymb} ) ) {
+        return $self->{DISCUSSION_TIME}->{$ressymb} > $self->{LAST_READ}->{$ressymb};
+    } else {
+#        return $self->{DISCUSSION_TIME}->{$ressymb} >  $self->{LAST_CHECK}; # v.1.1 behavior 
+        return $self->{DISCUSSION_TIME}->{$ressymb} >  0; # in 1.2 will display speech bubble icons for all items with posts until marked as read (even if read in v 1.1).
+    }
+}
+
+sub last_post_time {
+    my $self = shift;
+    my $symb = shift;
+    my $ressymb = $self->wrap_symb($symb);
+    return $self->{DISCUSSION_TIME}->{$ressymb};
+}
+
+sub unread_discussion {
+    my $self = shift;
+    my $symb = shift;
+
+    $self->get_discussion_data();
+
+    my $ressymb = $self->wrap_symb($symb);
+    # keys used to store bulletinboard postings use 'unwrapped' symb. 
+    my $discsymb = $self->unwrap_symb($ressymb);
+    my $version = $self->{DISCUSSION_DATA}{'version:'.$discsymb};
+    if (!$version) { return; }
+
+    my $prevread = $self->{LAST_READ}{$ressymb};
+
+    my $unreadcount = 0;
+    my $hiddenflag = 0;
+    my $deletedflag = 0;
+    my ($hidden,$deleted);
+
+    my %subjects;
+
+    for (my $id=$version; $id>0; $id--) {
+	my $vkeys=$self->{DISCUSSION_DATA}{$id.':keys:'.$discsymb};
+	my @keys=split(/:/,$vkeys);
+	if (grep(/^hidden$/ ,@keys)) {
+	    if (!$hiddenflag) {
+		$hidden = $self->{DISCUSSION_DATA}{$id.':'.$discsymb.':hidden'};
+		$hiddenflag = 1;
+	    }
+	} elsif (grep(/^deleted$/,@keys)) {
+	    if (!$deletedflag) {
+		$deleted = $self->{DISCUSSION_DATA}{$id.':'.$discsymb.':deleted'};
+		$deletedflag = 1;
+	    }
+	} else {
+	    if (($hidden !~/\.$id\./) && ($deleted !~/\.$id\./)
+		&& $prevread < $self->{DISCUSSION_DATA}{$id.':'.$discsymb.':timestamp'}) {
+		    $unreadcount++;
+		    $subjects{$unreadcount}=
+			$id.': '.$self->{DISCUSSION_DATA}{$id.':'.$discsymb.':subject'};
+		}
+	}
+    }
+    if (wantarray) {
+	return ($unreadcount,\%subjects);
+    }
+    return $unreadcount
+}
+
+sub wrap_symb {
+    my $self = shift;
+    my $symb = shift;
+    if ($symb =~ m-___(adm/[^/]+/[^/]+/)(\d+)(/bulletinboard)$-) {
+        unless ($symb =~ m|adm/wrapper/adm|) {
+            $symb = 'bulletin___'.$2.'___adm/wrapper/'.$1.$2.$3;
+        }
+    }
+    return $symb;
+}
+
+sub unwrap_symb {
+    my $self = shift;
+    my $ressymb = shift;
+    my $discsymb = $ressymb;
+    if ($ressymb =~ m-^(bulletin___\d+___)adm/wrapper/(adm/[^/]+/[^/]+/\d+/bulletinboard)$-) {
+         $discsymb = $1.$2;
+    }
+    return $discsymb;
+}
+
+# Private method: Does the given resource (as a symb string) have
+# current feedback? Returns the string in the feedback hash, which
+# will be false if it does not exist.
+
+sub getFeedback { 
+    my $self = shift;
+    my $symb = shift;
+
+    $self->generate_email_discuss_status();
+
+    if (!defined($self->{FEEDBACK})) { return ""; }
+    
+    return $self->{FEEDBACK}->{$symb};
+}
+
+# Private method: Get the errors for that resource (by source).
+sub getErrors { 
+    my $self = shift;
+    my $src = shift;
+
+    $self->generate_email_discuss_status();
+
+    if (!defined($self->{ERROR_MSG})) { return ""; }
+    return $self->{ERROR_MSG}->{$src};
+}
+
+=pod
+
+=item * B<getById>(id):
+
+Based on the ID of the resource (1.1, 3.2, etc.), get a resource
+object for that resource. This method, or other methods that use it
+(as in the resource object) is the only proper way to obtain a
+resource object.
+
+=item * B<getBySymb>(symb):
+
+Based on the symb of the resource, get a resource object for that
+resource. This is one of the proper ways to get a resource object.
+
+=item * B<getMapByMapPc>(map_pc):
+
+Based on the map_pc of the resource, get a resource object for
+the given map. This is one of the proper ways to get a resource object.
+
+=cut
+
+# The strategy here is to cache the resource objects, and only construct them
+# as we use them. The real point is to prevent reading any more from the tied
+# hash then we have to, which should hopefully alleviate speed problems.
+
+sub getById {
+    my $self = shift;
+    my $id = shift;
+
+    if (defined ($self->{RESOURCE_CACHE}->{$id}))
+    {
+        return $self->{RESOURCE_CACHE}->{$id};
+    }
+
+    # resource handles inserting itself into cache.
+    # Not clear why the quotes are necessary, but as of this
+    # writing it doesn't work without them.
+    return "Apache::lonnavmaps::resource"->new($self, $id);
+}
+
+sub getBySymb {
+    my $self = shift;
+    my $symb = shift;
+
+    my ($mapUrl, $id, $filename) = &Apache::lonnet::decode_symb($symb);
+    my $map = $self->getResourceByUrl($mapUrl);
+    my $returnvalue = undef;
+    if (ref($map)) {
+        $returnvalue = $self->getById($map->map_pc() .'.'.$id);
+    }
+    return $returnvalue;
+}
+
+sub getByMapPc {
+    my $self = shift;
+    my $map_pc = shift;
+    my $map_id = $self->{NAV_HASH}->{'map_id_' . $map_pc};
+    $map_id = $self->{NAV_HASH}->{'ids_' . $map_id};
+    return $self->getById($map_id);
+}
+
+=pod
+
+=item * B<firstResource>():
+
+Returns a resource object reference corresponding to the first
+resource in the navmap.
+
+=cut
+
+sub firstResource {
+    my $self = shift;
+    my $firstResource = $self->navhash('map_start_' .
+                     &Apache::lonnet::clutter($env{'request.course.uri'}));
+    return $self->getById($firstResource);
+}
+
+=pod
+
+=item * B<finishResource>():
+
+Returns a resource object reference corresponding to the last resource
+in the navmap.
+
+=cut
+
+sub finishResource {
+    my $self = shift;
+    my $firstResource = $self->navhash('map_finish_' .
+                     &Apache::lonnet::clutter($env{'request.course.uri'}));
+    return $self->getById($firstResource);
+}
+
+# Parmval reads the parm hash and cascades the lookups. parmval_real does
+# the actual lookup; parmval caches the results.
+sub parmval {
+    my $self = shift;
+    my ($what,$symb)=@_;
+    my $hashkey = $what."|||".$symb;
+
+    if (defined($self->{PARM_CACHE}->{$hashkey})) {
+        return $self->{PARM_CACHE}->{$hashkey};
+    }
+
+    my $result = $self->parmval_real($what, $symb);
+    $self->{PARM_CACHE}->{$hashkey} = $result;
+    return $result;
+}
+
+sub parmval_real {
+    my $self = shift;
+    my ($what,$symb,$recurse) = @_;
+
+    # Make sure the {USER_OPT} and {COURSE_OPT} hashes are populated
+    $self->generate_course_user_opt();
+
+    my $cid=$env{'request.course.id'};
+    my $csec=$env{'request.course.sec'};
+    my $cgroup='';
+    my @cgrps=split(/:/,$env{'request.course.groups'});
+    if (@cgrps > 0) {
+        @cgrps = sort(@cgrps);
+        $cgroup = $cgrps[0];
+    } 
+    my $uname=$env{'user.name'};
+    my $udom=$env{'user.domain'};
+
+    unless ($symb) { return ''; }
+    my $result='';
+
+    my ($mapname,$id,$fn)=&Apache::lonnet::decode_symb($symb);
+
+# ----------------------------------------------------- Cascading lookup scheme
+    my $rwhat=$what;
+    $what=~s/^parameter\_//;
+    $what=~s/\_/\./;
+
+    my $symbparm=$symb.'.'.$what;
+    my $mapparm=$mapname.'___(all).'.$what;
+    my $usercourseprefix=$cid;
+
+    my $grplevel=$usercourseprefix.'.['.$cgroup.'].'.$what;
+    my $grplevelr=$usercourseprefix.'.['.$cgroup.'].'.$symbparm;
+    my $grplevelm=$usercourseprefix.'.['.$cgroup.'].'.$mapparm;
+
+    my $seclevel= $usercourseprefix.'.['.$csec.'].'.$what;
+    my $seclevelr=$usercourseprefix.'.['.$csec.'].'.$symbparm;
+    my $seclevelm=$usercourseprefix.'.['.$csec.'].'.$mapparm;
+
+    my $courselevel= $usercourseprefix.'.'.$what;
+    my $courselevelr=$usercourseprefix.'.'.$symbparm;
+    my $courselevelm=$usercourseprefix.'.'.$mapparm;
+
+    my $useropt = $self->{USER_OPT};
+    my $courseopt = $self->{COURSE_OPT};
+    my $parmhash = $self->{PARM_HASH};
+
+# ---------------------------------------------------------- first, check user
+    if ($uname and defined($useropt)) {
+        if (defined($$useropt{$courselevelr})) { return $$useropt{$courselevelr}; }
+        if (defined($$useropt{$courselevelm})) { return $$useropt{$courselevelm}; }
+        if (defined($$useropt{$courselevel})) { return $$useropt{$courselevel}; }
+    }
+
+# ------------------------------------------------------- second, check course
+    if ($cgroup ne '' and defined($courseopt)) {
+        if (defined($$courseopt{$grplevelr})) { return $$courseopt{$grplevelr}; }
+        if (defined($$courseopt{$grplevelm})) { return $$courseopt{$grplevelm}; }
+        if (defined($$courseopt{$grplevel})) { return $$courseopt{$grplevel}; }
+    }
+
+    if ($csec and defined($courseopt)) {
+        if (defined($$courseopt{$seclevelr})) { return $$courseopt{$seclevelr}; }
+        if (defined($$courseopt{$seclevelm})) { return $$courseopt{$seclevelm}; }
+        if (defined($$courseopt{$seclevel})) { return $$courseopt{$seclevel}; }
+    }
+
+    if (defined($courseopt)) {
+        if (defined($$courseopt{$courselevelr})) { return $$courseopt{$courselevelr}; }
+    }
+
+# ----------------------------------------------------- third, check map parms
+
+    my $thisparm=$$parmhash{$symbparm};
+    if (defined($thisparm)) { return $thisparm; }
+
+# ----------------------------------------------------- fourth , check default
+
+    my $meta_rwhat=$rwhat;
+    $meta_rwhat=~s/\./_/g;
+    my $default=&Apache::lonnet::metadata($fn,$meta_rwhat);
+    if (defined($default)) { return $default}
+    $default=&Apache::lonnet::metadata($fn,'parameter_'.$meta_rwhat);
+    if (defined($default)) { return $default}
+
+# --------------------------------------------------- fifth, check more course
+    if (defined($courseopt)) {
+        if (defined($$courseopt{$courselevelm})) { return $$courseopt{$courselevelm}; }
+        if (defined($$courseopt{$courselevel})) { return $$courseopt{$courselevel}; }
+    }
+
+# --------------------------------------------------- sixth , cascade up parts
+
+    my ($space,@qualifier)=split(/\./,$rwhat);
+    my $qualifier=join('.',@qualifier);
+    unless ($space eq '0') {
+	my @parts=split(/_/,$space);
+	my $id=pop(@parts);
+	my $part=join('_',@parts);
+	if ($part eq '') { $part='0'; }
+	my $partgeneral=$self->parmval($part.".$qualifier",$symb,1);
+	if (defined($partgeneral)) { return $partgeneral; }
+    }
+    if ($recurse) { return undef; }
+    my $pack_def=&Apache::lonnet::packages_tab_default($fn,'resource.'.$what);
+    if (defined($pack_def)) { return $pack_def; }
+    return '';
+}
+
+=pod
+
+=item * B<getResourceByUrl>(url,multiple):
+
+Retrieves a resource object by URL of the resource, unless the optional
+multiple parameter is included in wahich caes an array of resource 
+objects is returned. If passed a resource object, it will simply return  
+it, so it is safe to use this method in code like
+"$res = $navmap->getResourceByUrl($res)"
+if you're not sure if $res is already an object, or just a URL. If the
+resource appears multiple times in the course, only the first instance 
+will be returned (useful for maps), unless the multiple parameter has
+been included, in which case all instances are returned in an array.
+
+=item * B<retrieveResources>(map, filterFunc, recursive, bailout, showall):
+
+The map is a specification of a map to retreive the resources from,
+either as a url or as an object. The filterFunc is a reference to a
+function that takes a resource object as its one argument and returns
+true if the resource should be included, or false if it should not
+be. If recursive is true, the map will be recursively examined,
+otherwise it will not be. If bailout is true, the function will return
+as soon as it finds a resource, if false it will finish. If showall is
+true it will not hide maps that contain nothing but one other map. By
+default, the map is the top-level map of the course, filterFunc is a
+function that always returns 1, recursive is true, bailout is false,
+showall is false. The resources will be returned in a list containing
+the resource objects for the corresponding resources, with B<no
+structure information> in the list; regardless of branching,
+recursion, etc., it will be a flat list.
+
+Thus, this is suitable for cases where you don't want the structure,
+just a list of all resources. It is also suitable for finding out how
+many resources match a given description; for this use, if all you
+want to know is if I<any> resources match the description, the bailout
+parameter will allow you to avoid potentially expensive enumeration of
+all matching resources.
+
+=item * B<hasResource>(map, filterFunc, recursive, showall):
+
+Convience method for
+
+ scalar(retrieveResources($map, $filterFunc, $recursive, 1, $showall)) > 0
+
+which will tell whether the map has resources matching the description
+in the filter function.
+
+=item * B<usedVersion>(url):
+
+Retrieves version infomation for a url. Returns the version (a number, or 
+the string "mostrecent") for resources which have version information in  
+the big hash.
+    
+=cut
+
+
+sub getResourceByUrl {
+    my $self = shift;
+    my $resUrl = shift;
+    my $multiple = shift;
+
+    if (ref($resUrl)) { return $resUrl; }
+
+    $resUrl = &Apache::lonnet::clutter($resUrl);
+    my $resId = $self->{NAV_HASH}->{'ids_' . $resUrl};
+    if (!$resId) { return ''; }
+    if ($multiple) {
+        my @resources = ();
+        my @resIds = split (/,/, $resId);
+        foreach my $id (@resIds) {
+            my $resourceId = $self->getById($id);
+            if ($resourceId) { 
+                push(@resources,$resourceId);
+            }
+        }
+        return @resources;
+    } else {
+        if ($resId =~ /,/) {
+            $resId = (split (/,/, $resId))[0];
+        }
+        return $self->getById($resId);
+    }
+}
+
+sub retrieveResources {
+    my $self = shift;
+    my $map = shift;
+    my $filterFunc = shift;
+    if (!defined ($filterFunc)) {
+        $filterFunc = sub {return 1;};
+    }
+    my $recursive = shift;
+    if (!defined($recursive)) { $recursive = 1; }
+    my $bailout = shift;
+    if (!defined($bailout)) { $bailout = 0; }
+    my $showall = shift;
+    # Create the necessary iterator.
+    if (!ref($map)) { # assume it's a url of a map.
+        $map = $self->getResourceByUrl($map);
+    }
+
+    # If nothing was passed, assume top-level map
+    if (!$map) {
+	$map = $self->getById('0.0');
+    }
+
+    # Check the map's validity.
+    if (!$map->is_map()) {
+        # Oh, to throw an exception.... how I'd love that!
+        return ();
+    }
+
+    # Get an iterator.
+    my $it = $self->getIterator($map->map_start(), $map->map_finish(),
+                                undef, $recursive, $showall);
+
+    my @resources = ();
+
+    # Run down the iterator and collect the resources.
+    my $curRes;
+
+    while ($curRes = $it->next()) {
+        if (ref($curRes)) {
+            if (!&$filterFunc($curRes)) {
+                next;
+            }
+
+            push @resources, $curRes;
+
+            if ($bailout) {
+                return @resources;
+            }
+        }
+
+    }
+
+    return @resources;
+}
+
+sub hasResource {
+    my $self = shift;
+    my $map = shift;
+    my $filterFunc = shift;
+    my $recursive = shift;
+    my $showall = shift;
+    
+    return scalar($self->retrieveResources($map, $filterFunc, $recursive, 1, $showall)) > 0;
+}
+
+sub usedVersion {
+    my $self = shift;
+    my $linkurl = shift;
+    return $self->navhash("version_$linkurl");
+}
 
 1;
+
+package Apache::lonnavmaps::iterator;
+use Scalar::Util qw(weaken);
+use Apache::lonnet;
+
+=pod
+
+=back
+
+=head1 Object: navmap Iterator
+
+An I<iterator> encapsulates the logic required to traverse a data
+structure. navmap uses an iterator to traverse the course map
+according to the criteria you wish to use.
+
+To obtain an iterator, call the B<getIterator>() function of a
+B<navmap> object. (Do not instantiate Apache::lonnavmaps::iterator
+directly.) This will return a reference to the iterator:
+
+C<my $resourceIterator = $navmap-E<gt>getIterator();>
+
+To get the next thing from the iterator, call B<next>:
+
+C<my $nextThing = $resourceIterator-E<gt>next()>
+
+getIterator behaves as follows:
+
+=over 4
+
+=item * B<getIterator>(firstResource, finishResource, filterHash, condition, forceTop, returnTopMap):
+
+All parameters are optional. firstResource is a resource reference
+corresponding to where the iterator should start. It defaults to
+navmap->firstResource() for the corresponding nav map. finishResource
+corresponds to where you want the iterator to end, defaulting to
+navmap->finishResource(). filterHash is a hash used as a set
+containing strings representing the resource IDs, defaulting to
+empty. Condition is a 1 or 0 that sets what to do with the filter
+hash: If a 0, then only resources that exist IN the filterHash will be
+recursed on. If it is a 1, only resources NOT in the filterHash will
+be recursed on. Defaults to 0. forceTop is a boolean value. If it is
+false (default), the iterator will only return the first level of map
+that is not just a single, 'redirecting' map. If true, the iterator
+will return all information, starting with the top-level map,
+regardless of content. returnTopMap, if true (default false), will
+cause the iterator to return the top-level map object (resource 0.0)
+before anything else.
+
+Thus, by default, only top-level resources will be shown. Change the
+condition to a 1 without changing the hash, and all resources will be
+shown. Changing the condition to 1 and including some values in the
+hash will allow you to selectively suppress parts of the navmap, while
+leaving it on 0 and adding things to the hash will allow you to
+selectively add parts of the nav map. See the handler code for
+examples.
+
+The iterator will return either a reference to a resource object, or a
+token representing something in the map, such as the beginning of a
+new branch. The possible tokens are:
+
+=over 4
+
+=item * B<END_ITERATOR>:
+
+The iterator has returned all that it's going to. Further calls to the
+iterator will just produce more of these. This is a "false" value, and
+is the only false value the iterator which will be returned, so it can
+be used as a loop sentinel.
+
+=item * B<BEGIN_MAP>:
+
+A new map is being recursed into. This is returned I<after> the map
+resource itself is returned.
+
+=item * B<END_MAP>:
+
+The map is now done.
+
+=item * B<BEGIN_BRANCH>:
+
+A branch is now starting. The next resource returned will be the first
+in that branch.
+
+=item * B<END_BRANCH>:
+
+The branch is now done.
+
+=back
+
+The tokens are retreivable via methods on the iterator object, i.e.,
+$iterator->END_MAP.
+
+Maps can contain empty resources. The iterator will automatically skip
+over such resources, but will still treat the structure
+correctly. Thus, a complicated map with several branches, but
+consisting entirely of empty resources except for one beginning or
+ending resource, will cause a lot of BRANCH_STARTs and BRANCH_ENDs,
+but only one resource will be returned.
+
+=back
+
+=head2 Normal Usage
+
+Normal usage of the iterator object is to do the following:
+
+ my $it = $navmap->getIterator([your params here]);
+ my $curRes;
+ while ($curRes = $it->next()) {
+   [your logic here]
+ }
+
+Note that inside of the loop, it's frequently useful to check if
+"$curRes" is a reference or not with the reference function; only
+resource objects will be references, and any non-references will 
+be the tokens described above.
+
+Also note there is some old code floating around that trys to track
+the depth of the iterator to see when it's done; do not copy that 
+code. It is difficult to get right and harder to understand then
+this. They should be migrated to this new style.
+
+=cut
+
+# Here are the tokens for the iterator:
+
+sub END_ITERATOR { return 0; }
+sub BEGIN_MAP { return 1; }    # begining of a new map
+sub END_MAP { return 2; }      # end of the map
+sub BEGIN_BRANCH { return 3; } # beginning of a branch
+sub END_BRANCH { return 4; }   # end of a branch
+sub FORWARD { return 1; }      # go forward
+sub BACKWARD { return 2; }
+
+sub min {
+    (my $a, my $b) = @_;
+    if ($a < $b) { return $a; } else { return $b; }
+}
+
+sub new {
+    # magic invocation to create a class instance
+    my $proto = shift;
+    my $class = ref($proto) || $proto;
+    my $self = {};
+
+    weaken($self->{NAV_MAP} = shift);
+    return undef unless ($self->{NAV_MAP});
+
+    # Handle the parameters
+    $self->{FIRST_RESOURCE} = shift || $self->{NAV_MAP}->firstResource();
+    $self->{FINISH_RESOURCE} = shift || $self->{NAV_MAP}->finishResource();
+
+    # If the given resources are just the ID of the resource, get the
+    # objects
+    if (!ref($self->{FIRST_RESOURCE})) { $self->{FIRST_RESOURCE} = 
+             $self->{NAV_MAP}->getById($self->{FIRST_RESOURCE}); }
+    if (!ref($self->{FINISH_RESOURCE})) { $self->{FINISH_RESOURCE} = 
+             $self->{NAV_MAP}->getById($self->{FINISH_RESOURCE}); }
+
+    $self->{FILTER} = shift;
+
+    # A hash, used as a set, of resource already seen
+    $self->{ALREADY_SEEN} = shift;
+    if (!defined($self->{ALREADY_SEEN})) { $self->{ALREADY_SEEN} = {} };
+    $self->{CONDITION} = shift;
+
+    # Do we want to automatically follow "redirection" maps?
+    $self->{FORCE_TOP} = shift;
+
+    # Do we want to return the top-level map object (resource 0.0)?
+    $self->{RETURN_0} = shift;
+    # have we done that yet?
+    $self->{HAVE_RETURNED_0} = 0;
+
+    # Now, we need to pre-process the map, by walking forward and backward
+    # over the parts of the map we're going to look at.
+
+    # The processing steps are exactly the same, except for a few small 
+    # changes, so I bundle those up in the following list of two elements:
+    # (direction_to_iterate, VAL_name, next_resource_method_to_call,
+    # first_resource).
+    # This prevents writing nearly-identical code twice.
+    my @iterations = ( [FORWARD(), 'TOP_DOWN_VAL', 'getNext', 
+                        'FIRST_RESOURCE'],
+                       [BACKWARD(), 'BOT_UP_VAL', 'getPrevious', 
+                        'FINISH_RESOURCE'] );
+
+    my $maxDepth = 0; # tracks max depth
+
+    # If there is only one resource in this map, and it's a map, we
+    # want to remember that, so the user can ask for the first map
+    # that isn't just a redirector.
+    my $resource; my $resourceCount = 0;
+
+    # Documentation on this algorithm can be found in the CVS repository at 
+    # /docs/lonnavdocs; these "**#**" markers correspond to documentation
+    # in that file.
+    # **1**
+
+    foreach my $pass (@iterations) {
+        my $direction = $pass->[0];
+        my $valName = $pass->[1];
+        my $nextResourceMethod = $pass->[2];
+        my $firstResourceName = $pass->[3];
+
+        my $iterator = Apache::lonnavmaps::DFSiterator->new($self->{NAV_MAP}, 
+                                                            $self->{FIRST_RESOURCE},
+                                                            $self->{FINISH_RESOURCE},
+                                                            {}, undef, 0, $direction);
+    
+        # prime the recursion
+        $self->{$firstResourceName}->{DATA}->{$valName} = 0;
+	$iterator->next();
+        my $curRes = $iterator->next();
+	my $depth = 1;
+        while ($depth > 0) {
+	    if ($curRes == $iterator->BEGIN_MAP()) { $depth++; }
+	    if ($curRes == $iterator->END_MAP()) { $depth--; }
+
+            if (ref($curRes)) {
+                # If there's only one resource, this will save it
+                # we have to filter empty resources from consideration here,
+                # or even "empty", redirecting maps have two (start & finish)
+                # or three (start, finish, plus redirector)
+                if($direction == FORWARD && $curRes->src()) { 
+                    $resource = $curRes; $resourceCount++; 
+                }
+                my $resultingVal = $curRes->{DATA}->{$valName};
+                my $nextResources = $curRes->$nextResourceMethod();
+                my $nextCount = scalar(@{$nextResources});
+
+                if ($nextCount == 1) { # **3**
+                    my $current = $nextResources->[0]->{DATA}->{$valName} || 999999999;
+                    $nextResources->[0]->{DATA}->{$valName} = min($resultingVal, $current);
+                }
+                
+                if ($nextCount > 1) { # **4**
+                    foreach my $res (@{$nextResources}) {
+                        my $current = $res->{DATA}->{$valName} || 999999999;
+                        $res->{DATA}->{$valName} = min($current, $resultingVal + 1);
+                    }
+                }
+            }
+            
+            # Assign the final val (**2**)
+            if (ref($curRes) && $direction == BACKWARD()) {
+                my $finalDepth = min($curRes->{DATA}->{TOP_DOWN_VAL},
+                                     $curRes->{DATA}->{BOT_UP_VAL});
+                
+                $curRes->{DATA}->{DISPLAY_DEPTH} = $finalDepth;
+                if ($finalDepth > $maxDepth) {$maxDepth = $finalDepth;}
+            }
+
+	    $curRes = $iterator->next();
+        }
+    }
+
+    # Check: Was this only one resource, a map?
+    if ($resourceCount == 1 && $resource->is_sequence() && !$self->{FORCE_TOP}) { 
+        my $firstResource = $resource->map_start();
+        my $finishResource = $resource->map_finish();
+        return 
+            Apache::lonnavmaps::iterator->new($self->{NAV_MAP}, $firstResource,
+                                              $finishResource, $self->{FILTER},
+                                              $self->{ALREADY_SEEN}, 
+                                              $self->{CONDITION},
+					      $self->{FORCE_TOP});
+        
+    }
+
+    # Set up some bookkeeping information.
+    $self->{CURRENT_DEPTH} = 0;
+    $self->{MAX_DEPTH} = $maxDepth;
+    $self->{STACK} = [];
+    $self->{RECURSIVE_ITERATOR_FLAG} = 0;
+    $self->{FINISHED} = 0; # When true, the iterator has finished
+
+    for (my $i = 0; $i <= $self->{MAX_DEPTH}; $i++) {
+        push @{$self->{STACK}}, [];
+    }
+
+    # Prime the recursion w/ the first resource **5**
+    push @{$self->{STACK}->[0]}, $self->{FIRST_RESOURCE};
+    $self->{ALREADY_SEEN}->{$self->{FIRST_RESOURCE}->{ID}} = 1;
+
+    bless ($self);
+
+    return $self;
+}
+
+sub next {
+    my $self = shift;
+    my $closeAllPages=shift;
+    if ($self->{FINISHED}) {
+	return END_ITERATOR();
+    }
+
+    # If we want to return the top-level map object, and haven't yet,
+    # do so.
+    if ($self->{RETURN_0} && !$self->{HAVE_RETURNED_0}) {
+        $self->{HAVE_RETURNED_0} = 1;
+        return $self->{NAV_MAP}->getById('0.0');
+    }
+
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
+        # grab the next from the recursive iterator 
+        my $next = $self->{RECURSIVE_ITERATOR}->next($closeAllPages);
+
+        # is it a begin or end map? If so, update the depth
+        if ($next == BEGIN_MAP() ) { $self->{RECURSIVE_DEPTH}++; }
+        if ($next == END_MAP() ) { $self->{RECURSIVE_DEPTH}--; }
+
+        # Are we back at depth 0? If so, stop recursing
+        if ($self->{RECURSIVE_DEPTH} == 0) {
+            $self->{RECURSIVE_ITERATOR_FLAG} = 0;
+        }
+
+        return $next;
+    }
+
+    if (defined($self->{FORCE_NEXT})) {
+        my $tmp = $self->{FORCE_NEXT};
+        $self->{FORCE_NEXT} = undef;
+        return $tmp;
+    }
+
+    # Have we not yet begun? If not, return BEGIN_MAP and
+    # remember we've started.
+    if ( !$self->{STARTED} ) { 
+        $self->{STARTED} = 1;
+        return $self->BEGIN_MAP();
+    }
+
+    # Here's the guts of the iterator.
+    
+    # Find the next resource, if any.
+    my $found = 0;
+    my $i = $self->{MAX_DEPTH};
+    my $newDepth;
+    my $here;
+    while ( $i >= 0 && !$found ) {
+        if ( scalar(@{$self->{STACK}->[$i]}) > 0 ) { # **6**
+            $here = pop @{$self->{STACK}->[$i]}; # **7**
+            $found = 1;
+            $newDepth = $i;
+        }
+        $i--;
+    }
+
+    # If we still didn't find anything, we're done.
+    if ( !$found ) {
+        # We need to get back down to the correct branch depth
+        if ( $self->{CURRENT_DEPTH} > 0 ) {
+            $self->{CURRENT_DEPTH}--;
+            return END_BRANCH();
+        } else {
+	    $self->{FINISHED} = 1;
+            return END_MAP();
+        }
+    }
+
+    # If this is not a resource, it must be an END_BRANCH marker we want
+    # to return directly.
+    if (!ref($here)) { # **8**
+        if ($here == END_BRANCH()) { # paranoia, in case of later extension
+            $self->{CURRENT_DEPTH}--;
+            return $here;
+        }
+    }
+
+    # Otherwise, it is a resource and it's safe to store in $self->{HERE}
+    $self->{HERE} = $here;
+
+    # Get to the right level
+    if ( $self->{CURRENT_DEPTH} > $newDepth ) {
+        push @{$self->{STACK}->[$newDepth]}, $here;
+        $self->{CURRENT_DEPTH}--;
+        return END_BRANCH();
+    }
+    if ( $self->{CURRENT_DEPTH} < $newDepth) {
+        push @{$self->{STACK}->[$newDepth]}, $here;
+        $self->{CURRENT_DEPTH}++;
+        return BEGIN_BRANCH();
+    }
+
+    # If we made it here, we have the next resource, and we're at the
+    # right branch level. So let's examine the resource for where
+    # we can get to from here.
+
+    # So we need to look at all the resources we can get to from here,
+    # categorize them if we haven't seen them, remember if we have a new
+    my $nextUnfiltered = $here->getNext();
+    my $maxDepthAdded = -1;
+    
+    for (@$nextUnfiltered) {
+        if (!defined($self->{ALREADY_SEEN}->{$_->{ID}})) {
+            my $depth = $_->{DATA}->{DISPLAY_DEPTH};
+            push @{$self->{STACK}->[$depth]}, $_;
+            $self->{ALREADY_SEEN}->{$_->{ID}} = 1;
+            if ($maxDepthAdded < $depth) { $maxDepthAdded = $depth; }
+        }
+    }
+
+    # Is this the end of a branch? If so, all of the resources examined above
+    # led to lower levels then the one we are currently at, so we push a END_BRANCH
+    # marker onto the stack so we don't forget.
+    # Example: For the usual A(BC)(DE)F case, when the iterator goes down the
+    # BC branch and gets to C, it will see F as the only next resource, but it's
+    # one level lower. Thus, this is the end of the branch, since there are no
+    # more resources added to this level or above.
+    # We don't do this if the examined resource is the finish resource,
+    # because the condition given above is true, but the "END_MAP" will
+    # take care of things and we should already be at depth 0.
+    my $isEndOfBranch = $maxDepthAdded < $self->{CURRENT_DEPTH};
+    if ($isEndOfBranch && $here != $self->{FINISH_RESOURCE}) { # **9**
+        push @{$self->{STACK}->[$self->{CURRENT_DEPTH}]}, END_BRANCH();
+    }
+
+    # That ends the main iterator logic. Now, do we want to recurse
+    # down this map (if this resource is a map)?
+    if ( ($self->{HERE}->is_sequence() || (!$closeAllPages && $self->{HERE}->is_page())) &&
+        (defined($self->{FILTER}->{$self->{HERE}->map_pc()}) xor $self->{CONDITION})) {
+        $self->{RECURSIVE_ITERATOR_FLAG} = 1;
+        my $firstResource = $self->{HERE}->map_start();
+        my $finishResource = $self->{HERE}->map_finish();
+
+        $self->{RECURSIVE_ITERATOR} = 
+            Apache::lonnavmaps::iterator->new($self->{NAV_MAP}, $firstResource,
+                                              $finishResource, $self->{FILTER},
+                                              $self->{ALREADY_SEEN},
+					      $self->{CONDITION},
+					      $self->{FORCE_TOP});
+    }
+
+    # If this is a blank resource, don't actually return it.
+    # Should you ever find you need it, make sure to add an option to the code
+    #  that you can use; other things depend on this behavior.
+    my $browsePriv = $self->{HERE}->browsePriv();
+    if (!$self->{HERE}->src() || 
+        (!($browsePriv eq 'F') && !($browsePriv eq '2')) ) {
+        return $self->next($closeAllPages);
+    }
+
+    return $self->{HERE};
+
+}
+
+=pod
+
+The other method available on the iterator is B<getStack>, which
+returns an array populated with the current 'stack' of maps, as
+references to the resource objects. Example: This is useful when
+making the navigation map, as we need to check whether we are under a
+page map to see if we need to link directly to the resource, or to the
+page. The first elements in the array will correspond to the top of
+the stack (most inclusive map).
+
+=cut
+
+sub getStack {
+    my $self=shift;
+
+    my @stack;
+
+    $self->populateStack(\@stack);
+
+    return \@stack;
+}
+
+# Private method: Calls the iterators recursively to populate the stack.
+sub populateStack {
+    my $self=shift;
+    my $stack = shift;
+
+    push @$stack, $self->{HERE} if ($self->{HERE});
+
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
+        $self->{RECURSIVE_ITERATOR}->populateStack($stack);
+    }
+}
+
+1;
+
+package Apache::lonnavmaps::DFSiterator;
+use Scalar::Util qw(weaken);
+use Apache::lonnet;
+
+# Not documented in the perldoc: This is a simple iterator that just walks
+#  through the nav map and presents the resources in a depth-first search
+#  fashion, ignorant of conditionals, randomized resources, etc. It presents
+#  BEGIN_MAP and END_MAP, but does not understand branches at all. It is
+#  useful for pre-processing of some kind, and is in fact used by the main
+#  iterator that way, but that's about it.
+# One could imagine merging this into the init routine of the main iterator,
+#  but this might as well be left separate, since it is possible some other
+#  use might be found for it. - Jeremy
+
+# Unlike the main iterator, this DOES return all resources, even blank ones.
+#  The main iterator needs them to correctly preprocess the map.
+
+sub BEGIN_MAP { return 1; }    # begining of a new map
+sub END_MAP { return 2; }      # end of the map
+sub FORWARD { return 1; }      # go forward
+sub BACKWARD { return 2; }
+
+# Params: Nav map ref, first resource id/ref, finish resource id/ref,
+#         filter hash ref (or undef), already seen hash or undef, condition
+#         (as in main iterator), direction FORWARD or BACKWARD (undef->forward).
+sub new {
+    # magic invocation to create a class instance
+    my $proto = shift;
+    my $class = ref($proto) || $proto;
+    my $self = {};
+
+    weaken($self->{NAV_MAP} = shift);
+    return undef unless ($self->{NAV_MAP});
+
+    $self->{FIRST_RESOURCE} = shift || $self->{NAV_MAP}->firstResource();
+    $self->{FINISH_RESOURCE} = shift || $self->{NAV_MAP}->finishResource();
+
+    # If the given resources are just the ID of the resource, get the
+    # objects
+    if (!ref($self->{FIRST_RESOURCE})) { $self->{FIRST_RESOURCE} = 
+             $self->{NAV_MAP}->getById($self->{FIRST_RESOURCE}); }
+    if (!ref($self->{FINISH_RESOURCE})) { $self->{FINISH_RESOURCE} = 
+             $self->{NAV_MAP}->getById($self->{FINISH_RESOURCE}); }
+
+    $self->{FILTER} = shift;
+
+    # A hash, used as a set, of resource already seen
+    $self->{ALREADY_SEEN} = shift;
+     if (!defined($self->{ALREADY_SEEN})) { $self->{ALREADY_SEEN} = {} };
+    $self->{CONDITION} = shift;
+    $self->{DIRECTION} = shift || FORWARD();
+
+    # Flag: Have we started yet?
+    $self->{STARTED} = 0;
+
+    # Should we continue calling the recursive iterator, if any?
+    $self->{RECURSIVE_ITERATOR_FLAG} = 0;
+    # The recursive iterator, if any
+    $self->{RECURSIVE_ITERATOR} = undef;
+    # Are we recursing on a map, or a branch?
+    $self->{RECURSIVE_MAP} = 1; # we'll manually unset this when recursing on branches
+    # And the count of how deep it is, so that this iterator can keep track of
+    # when to pick back up again.
+    $self->{RECURSIVE_DEPTH} = 0;
+
+    # For keeping track of our branches, we maintain our own stack
+    $self->{STACK} = [];
+
+    # Start with the first resource
+    if ($self->{DIRECTION} == FORWARD) {
+        push @{$self->{STACK}}, $self->{FIRST_RESOURCE};
+    } else {
+        push @{$self->{STACK}}, $self->{FINISH_RESOURCE};
+    }
+
+    bless($self);
+    return $self;
+}
+
+sub next {
+    my $self = shift;
+    
+    # Are we using a recursive iterator? If so, pull from that and
+    # watch the depth; we want to resume our level at the correct time.
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
+        # grab the next from the recursive iterator
+        my $next = $self->{RECURSIVE_ITERATOR}->next();
+        
+        # is it a begin or end map? Update depth if so
+        if ($next == BEGIN_MAP() ) { $self->{RECURSIVE_DEPTH}++; }
+        if ($next == END_MAP() ) { $self->{RECURSIVE_DEPTH}--; }
+
+        # Are we back at depth 0? If so, stop recursing.
+        if ($self->{RECURSIVE_DEPTH} == 0) {
+            $self->{RECURSIVE_ITERATOR_FLAG} = 0;
+        }
+        
+        return $next;
+    }
+
+    # Is there a current resource to grab? If not, then return
+    # END_MAP, which will end the iterator.
+    if (scalar(@{$self->{STACK}}) == 0) {
+        return $self->END_MAP();
+    }
+
+    # Have we not yet begun? If not, return BEGIN_MAP and 
+    # remember that we've started.
+    if ( !$self->{STARTED} ) {
+        $self->{STARTED} = 1;
+        return $self->BEGIN_MAP;
+    }
+
+    # Get the next resource in the branch
+    $self->{HERE} = pop @{$self->{STACK}};
+
+    # remember that we've seen this, so we don't return it again later
+    $self->{ALREADY_SEEN}->{$self->{HERE}->{ID}} = 1;
+    
+    # Get the next possible resources
+    my $nextUnfiltered;
+    if ($self->{DIRECTION} == FORWARD()) {
+        $nextUnfiltered = $self->{HERE}->getNext();
+    } else {
+        $nextUnfiltered = $self->{HERE}->getPrevious();
+    }
+    my $next = [];
+
+    # filter the next possibilities to remove things we've 
+    # already seen.
+    foreach (@$nextUnfiltered) {
+        if (!defined($self->{ALREADY_SEEN}->{$_->{ID}})) {
+            push @$next, $_;
+        }
+    }
+
+    while (@$next) {
+        # copy the next possibilities over to the stack
+        push @{$self->{STACK}}, shift @$next;
+    }
+
+    # If this is a map and we want to recurse down it... (not filtered out)
+    if ($self->{HERE}->is_map() && 
+         (defined($self->{FILTER}->{$self->{HERE}->map_pc()}) xor $self->{CONDITION})) { 
+        $self->{RECURSIVE_ITERATOR_FLAG} = 1;
+        my $firstResource = $self->{HERE}->map_start();
+        my $finishResource = $self->{HERE}->map_finish();
+
+        $self->{RECURSIVE_ITERATOR} =
+          Apache::lonnavmaps::DFSiterator->new ($self->{NAV_MAP}, $firstResource, 
+                     $finishResource, $self->{FILTER}, $self->{ALREADY_SEEN},
+                                             $self->{CONDITION}, $self->{DIRECTION});
+    }
+
+    return $self->{HERE};
+}
+
+# Identical to the full iterator methods of the same name. Hate to copy/paste
+# but I also hate to "inherit" either iterator from the other.
+
+sub getStack {
+    my $self=shift;
+
+    my @stack;
+
+    $self->populateStack(\@stack);
+
+    return \@stack;
+}
+
+# Private method: Calls the iterators recursively to populate the stack.
+sub populateStack {
+    my $self=shift;
+    my $stack = shift;
+
+    push @$stack, $self->{HERE} if ($self->{HERE});
+
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
+        $self->{RECURSIVE_ITERATOR}->populateStack($stack);
+    }
+}
+
+1;
+
+package Apache::lonnavmaps::resource;
+use Scalar::Util qw(weaken);
+use Apache::lonnet;
+
+=pod
+
+=head1 Object: resource 
+
+X<resource, navmap object>
+A resource object encapsulates a resource in a resource map, allowing
+easy manipulation of the resource, querying the properties of the
+resource (including user properties), and represents a reference that
+can be used as the canonical representation of the resource by
+lonnavmap clients like renderers.
+
+A resource only makes sense in the context of a navmap, as some of the
+data is stored in the navmap object.
+
+You will probably never need to instantiate this object directly. Use
+Apache::lonnavmaps::navmap, and use the "start" method to obtain the
+starting resource.
+
+Resource objects respect the parameter_hiddenparts, which suppresses 
+various parts according to the wishes of the map author. As of this
+writing, there is no way to override this parameter, and suppressed
+parts will never be returned, nor will their response types or ids be
+stored.
+
+=head2 Overview
+
+A B<Resource> is the most granular type of object in LON-CAPA that can
+be included in a course. It can either be a particular resource, like
+an HTML page, external resource, problem, etc., or it can be a
+container sequence, such as a "page" or a "map".
+
+To see a sequence from the user's point of view, please see the
+B<Creating a Course: Maps and Sequences> chapter of the Author's
+Manual.
+
+A Resource Object, once obtained from a navmap object via a B<getBy*>
+method of the navmap, or from an iterator, allows you to query
+information about that resource.
+
+Generally, you do not ever want to create a resource object yourself,
+so creation has been left undocumented. Always retrieve resources
+from navmap objects.
+
+=head3 Identifying Resources
+
+X<big hash>Every resource is identified by a Resource ID in the big hash that is
+unique to that resource for a given course. X<resource ID, in big hash>
+The Resource ID has the form #.#, where the first number is the same
+for every resource in a map, and the second is unique. For instance,
+for a course laid out like this:
+
+ * Problem 1
+ * Map
+   * Resource 2
+   * Resource 3
+
+C<Problem 1> and C<Map> will share a first number, and C<Resource 2>
+C<Resource 3> will share a first number. The second number may end up
+re-used between the two groups.
+
+The resource ID is only used in the big hash, but can be used in the
+context of a course to identify a resource easily. (For instance, the
+printing system uses it to record which resources from a sequence you 
+wish to print.)
+
+X<symb> X<resource, symb>
+All resources also have B<symb>s, which uniquely identify a resource
+in a course. Many internal LON-CAPA functions expect a symb. A symb
+carries along with it the URL of the resource, and the map it appears
+in. Symbs are much larger then resource IDs.
+
+=cut
+
+sub new {
+    # magic invocation to create a class instance
+    my $proto = shift;
+    my $class = ref($proto) || $proto;
+    my $self = {};
+
+    weaken($self->{NAV_MAP} = shift);
+    $self->{ID} = shift;
+
+    # Store this new resource in the parent nav map's cache.
+    $self->{NAV_MAP}->{RESOURCE_CACHE}->{$self->{ID}} = $self;
+    $self->{RESOURCE_ERROR} = 0;
+
+    # A hash that can be used by two-pass algorithms to store data
+    # about this resource in. Not used by the resource object
+    # directly.
+    $self->{DATA} = {};
+   
+    bless($self);
+    
+    return $self;
+}
+
+# private function: simplify the NAV_HASH lookups we keep doing
+# pass the name, and to automatically append my ID, pass a true val on the
+# second param
+sub navHash {
+    my $self = shift;
+    my $param = shift;
+    my $id = shift;
+    return $self->{NAV_MAP}->navhash($param . ($id?$self->{ID}:""));
+}
+
+=pod
+
+=head2 Methods
+
+Once you have a resource object, here's what you can do with it:
+
+=head3 Attribute Retrieval
+
+Every resource has certain attributes that can be retrieved and used:
+
+=over 4
+
+=item * B<ID>: Every resource has an ID that is unique for that
+    resource in the course it is in. The ID is actually in the hash
+    representing the resource, so for a resource object $res, obtain
+    it via C<$res->{ID}).
+
+=item * B<compTitle>:
+
+Returns a "composite title", that is equal to $res->title() if the
+resource has a title, and is otherwise the last part of the URL (e.g.,
+"problem.problem").
+
+=item * B<ext>:
+
+Returns true if the resource is external.
+
+=item * B<kind>:
+
+Returns the kind of the resource from the compiled nav map.
+
+=item * B<randomout>:
+
+Returns true if this resource was chosen to NOT be shown to the user
+by the random map selection feature. In other words, this is usually
+false.
+
+=item * B<randompick>:
+
+Returns true for a map if the randompick feature is being used on the
+map. (?)
+
+=item * B<src>:
+
+Returns the source for the resource.
+
+=item * B<symb>:
+
+Returns the symb for the resource.
+
+=item * B<title>:
+
+Returns the title of the resource.
+
+=back
+
+=cut
+
+# These info functions can be used directly, as they don't return
+# resource information.
+sub comesfrom { my $self=shift; return $self->navHash("comesfrom_", 1); }
+sub encrypted { my $self=shift; return $self->navHash("encrypted_", 1); }
+sub ext { my $self=shift; return $self->navHash("ext_", 1) eq 'true:'; }
+sub from { my $self=shift; return $self->navHash("from_", 1); }
+# considered private and undocumented
+sub goesto { my $self=shift; return $self->navHash("goesto_", 1); }
+sub kind { my $self=shift; return $self->navHash("kind_", 1); }
+sub randomout { my $self=shift; return $self->navHash("randomout_", 1); }
+sub randompick { 
+    my $self = shift;
+    return $self->parmval('randompick');
+}
+sub link {
+    my $self=shift;
+    if ($self->encrypted()) { return &Apache::lonenc::encrypted($self->src); }
+    return $self->src;
+}
+sub src { 
+    my $self=shift;
+    return $self->navHash("src_", 1);
+}
+sub shown_symb {
+    my $self=shift;
+    if ($self->encrypted()) {return &Apache::lonenc::encrypted($self->symb());}
+    return $self->symb();
+}
+sub id {
+    my $self=shift;
+    return $self->{ID};
+}
+sub enclosing_map_src {
+    my $self=shift;
+    (my $first, my $second) = $self->{ID} =~ /(\d+).(\d+)/;
+    return $self->navHash('map_id_'.$first);
+}
+sub symb {
+    my $self=shift;
+    (my $first, my $second) = $self->{ID} =~ /(\d+).(\d+)/;
+    my $symbSrc = &Apache::lonnet::declutter($self->src());
+    my $symb = &Apache::lonnet::declutter($self->navHash('map_id_'.$first)) 
+        . '___' . $second . '___' . $symbSrc;
+    return &Apache::lonnet::symbclean($symb);
+}
+sub wrap_symb {
+    my $self = shift;
+    return $self->{NAV_MAP}->wrap_symb($self->symb());
+}
+sub title { 
+    my $self=shift; 
+    if ($self->{ID} eq '0.0') {
+	# If this is the top-level map, return the title of the course
+	# since this map can not be titled otherwise.
+	return $env{'course.'.$env{'request.course.id'}.'.description'};
+    }
+    return $self->navHash("title_", 1); }
+# considered private and undocumented
+sub to { my $self=shift; return $self->navHash("to_", 1); }
+sub condition {
+    my $self=shift;
+    my $undercond=$self->navHash("undercond_", 1);
+    if (!defined($undercond)) { return 1; };
+    my $condid=$self->navHash("condid_$undercond");
+    if (!defined($condid)) { return 1; };
+    my $condition=&Apache::lonnet::directcondval($condid);
+    return $condition;
+}
+sub condval {
+    my $self=shift;
+    my ($pathname,$filename) = 
+	&Apache::lonnet::split_uri_for_cond($self->src());
+
+    my $match=($env{'acc.res.'.$env{'request.course.id'}.'.'.$pathname}=~
+	       /\&\Q$filename\E\:([\d\|]+)\&/);
+    if ($match) {
+	return &Apache::lonnet::condval($1);
+    }
+    return 0;
+}
+sub compTitle {
+    my $self = shift;
+    my $title = $self->title();
+    $title=~s/\&colon\;/\:/gs;
+    if (!$title) {
+        $title = $self->src();
+        $title = substr($title, rindex($title, '/') + 1);
+    }
+    return $title;
+}
+=pod
+
+B<Predicate Testing the Resource>
+
+These methods are shortcuts to deciding if a given resource has a given property.
+
+=over 4
+
+=item * B<is_map>:
+
+Returns true if the resource is a map type.
+
+=item * B<is_problem>:
+
+Returns true if the resource is a problem type, false
+otherwise. (Looks at the extension on the src field; might need more
+to work correctly.)
+
+=item * B<is_page>:
+
+Returns true if the resource is a page.
+
+=item * B<is_sequence>:
+
+Returns true if the resource is a sequence.
+
+=back
+
+=cut
+
+sub hasResource {
+   my $self = shift;
+   return $self->{NAV_MAP}->hasResource(@_);
+}
+
+sub retrieveResources {
+   my $self = shift;
+   return $self->{NAV_MAP}->retrieveResources(@_);
+}
+
+sub is_exam {
+    my ($self,$part) = @_;
+    if ($self->parmval('type',$part) eq 'exam') {
+        return 1;
+    }
+    if ($self->src() =~ /\.(exam)$/) {
+        return 1;
+    }
+    return 0;
+}
+sub is_html {
+    my $self=shift;
+    my $src = $self->src();
+    return ($src =~ /html$/);
+}
+sub is_map { my $self=shift; return defined($self->navHash("is_map_", 1)); }
+sub is_page {
+    my $self=shift;
+    my $src = $self->src();
+    return $self->navHash("is_map_", 1) && 
+	$self->navHash("map_type_" . $self->map_pc()) eq 'page';
+}
+sub is_practice {
+    my $self=shift;
+    my ($part) = @_;
+    if ($self->parmval('type',$part) eq 'practice') {
+        return 1;
+    }
+    return 0;
+}
+sub is_problem {
+    my $self=shift;
+    my $src = $self->src();
+    if ($src =~ /\.(problem|exam|quiz|assess|survey|form|library|task)$/) {
+	return !($self->is_practice());
+    }
+    return 0;
+}
+sub contains_problem {
+    my $self=shift;
+    if ($self->is_page()) {
+	my $hasProblem=$self->hasResource($self,sub { $_[0]->is_problem() },1);
+	return $hasProblem;
+    }
+    return 0;
+}
+sub is_sequence {
+    my $self=shift;
+    my $src = $self->src();
+    return $self->navHash("is_map_", 1) && 
+	$self->navHash("map_type_" . $self->map_pc()) eq 'sequence';
+}
+sub is_survey {
+    my $self = shift();
+    my $part = shift();
+    if ($self->parmval('type',$part) eq 'survey') {
+        return 1;
+    }
+    if ($self->src() =~ /\.(survey)$/) {
+        return 1;
+    }
+    return 0;
+}
+sub is_task {
+    my $self=shift;
+    my $src = $self->src();
+    return ($src =~ /\.(task)$/)
+}
+
+sub is_empty_sequence {
+    my $self=shift;
+    my $src = $self->src();
+    return !$self->is_page() && $self->navHash("is_map_", 1) && !$self->navHash("map_type_" . $self->map_pc());
+}
+
+# Private method: Shells out to the parmval in the nav map, handler parts.
+sub parmval {
+    my $self = shift;
+    my $what = shift;
+    my $part = shift;
+    if (!defined($part)) { 
+        $part = '0'; 
+    }
+    return $self->{NAV_MAP}->parmval($part.'.'.$what, $self->symb());
+}
+
+=pod
+
+B<Map Methods>
+
+These methods are useful for getting information about the map
+properties of the resource, if the resource is a map (B<is_map>).
+
+=over 4
+
+=item * B<map_finish>:
+
+Returns a reference to a resource object corresponding to the finish
+resource of the map.
+
+=item * B<map_pc>:
+
+Returns the pc value of the map, which is the first number that
+appears in the resource ID of the resources in the map, and is the
+number that appears around the middle of the symbs of the resources in
+that map.
+
+=item * B<map_start>:
+
+Returns a reference to a resource object corresponding to the start
+resource of the map.
+
+=item * B<map_type>:
+
+Returns a string with the type of the map in it.
+
+=back
+
+=cut
+
+sub map_finish {
+    my $self = shift;
+    my $src = $self->src();
+    $src = Apache::lonnet::clutter($src);
+    my $res = $self->navHash("map_finish_$src", 0);
+    $res = $self->{NAV_MAP}->getById($res);
+    return $res;
+}
+sub map_pc {
+    my $self = shift;
+    my $src = $self->src();
+    return $self->navHash("map_pc_$src", 0);
+}
+sub map_start {
+    my $self = shift;
+    my $src = $self->src();
+    $src = Apache::lonnet::clutter($src);
+    my $res = $self->navHash("map_start_$src", 0);
+    $res = $self->{NAV_MAP}->getById($res);
+    return $res;
+}
+sub map_type {
+    my $self = shift;
+    my $pc = $self->map_pc();
+    return $self->navHash("map_type_$pc", 0);
+}
+
+#####
+# Property queries
+#####
+
+# These functions will be responsible for returning the CORRECT
+# VALUE for the parameter, no matter what. So while they may look
+# like direct calls to parmval, they can be more then that.
+# So, for instance, the duedate function should use the "duedatetype"
+# information, rather then the resource object user.
+
+=pod
+
+=head2 Resource Parameters
+
+In order to use the resource parameters correctly, the nav map must
+have been instantiated with genCourseAndUserOptions set to true, so
+the courseopt and useropt is read correctly. Then, you can call these
+functions to get the relevant parameters for the resource. Each
+function defaults to part "0", but can be directed to another part by
+passing the part as the parameter.
+
+These methods are responsible for getting the parameter correct, not
+merely reflecting the contents of the GDBM hashes. As we move towards
+dates relative to other dates, these methods should be updated to
+reflect that. (Then, anybody using these methods will not have to update
+their code.)
+
+=over 4
+
+=item * B<acc>:
+
+Get the Client IP/Name Access Control information.
+
+=item * B<answerdate>:
+
+Get the answer-reveal date for the problem.
+
+=item * B<awarded>: 
+
+Gets the awarded value for the problem part. Requires genUserData set to
+true when the navmap object was created.
+
+=item * B<duedate>:
+
+Get the due date for the problem.
+
+=item * B<tries>:
+
+Get the number of tries the student has used on the problem.
+
+=item * B<maxtries>:
+
+Get the number of max tries allowed.
+
+=item * B<opendate>:
+
+Get the open date for the problem.
+
+=item * B<sig>:
+
+Get the significant figures setting.
+
+=item * B<tol>:
+
+Get the tolerance for the problem.
+
+=item * B<tries>:
+
+Get the number of tries the user has already used on the problem.
+
+=item * B<type>:
+
+Get the question type for the problem.
+
+=item * B<weight>:
+
+Get the weight for the problem.
+
+=back
+
+=cut
+
+sub acc {
+    (my $self, my $part) = @_;
+    return $self->parmval("acc", $part);
+}
+sub answerdate {
+    (my $self, my $part) = @_;
+    # Handle intervals
+    if ($self->parmval("answerdate.type", $part) eq 'date_interval') {
+        return $self->duedate($part) + 
+            $self->parmval("answerdate", $part);
+    }
+    return $self->parmval("answerdate", $part);
+}
+sub awarded { 
+    my $self = shift; my $part = shift;
+    $self->{NAV_MAP}->get_user_data();
+    if (!defined($part)) { $part = '0'; }
+    return $self->{NAV_MAP}->{STUDENT_DATA}->{$self->symb()}->{'resource.'.$part.'.awarded'};
+}
+sub duedate {
+    (my $self, my $part) = @_;
+    my $interval=$self->parmval("interval", $part);
+    if ($interval) {
+	my $first_access=&Apache::lonnet::get_first_access('map',$self->symb);
+	if ($first_access) { return ($first_access+$interval); }
+    }
+    return $self->parmval("duedate", $part);
+}
+sub handgrade {
+    (my $self, my $part) = @_;
+    return $self->parmval("handgrade", $part);
+}
+sub maxtries {
+    (my $self, my $part) = @_;
+    return $self->parmval("maxtries", $part);
+}
+sub opendate {
+    (my $self, my $part) = @_;
+    if ($self->parmval("opendate.type", $part) eq 'date_interval') {
+        return $self->duedate($part) -
+            $self->parmval("opendate", $part);
+    }
+    return $self->parmval("opendate");
+}
+sub problemstatus {
+    (my $self, my $part) = @_;
+    return lc $self->parmval("problemstatus", $part);
+}
+sub sig {
+    (my $self, my $part) = @_;
+    return $self->parmval("sig", $part);
+}
+sub tol {
+    (my $self, my $part) = @_;
+    return $self->parmval("tol", $part);
+}
+sub tries { 
+    my $self = shift; 
+    my $tries = $self->queryRestoreHash('tries', shift);
+    if (!defined($tries)) { return '0';}
+    return $tries;
+}
+sub type {
+    (my $self, my $part) = @_;
+    return $self->parmval("type", $part);
+}
+sub weight { 
+    my $self = shift; my $part = shift;
+    if (!defined($part)) { $part = '0'; }
+    return &Apache::lonnet::EXT('resource.'.$part.'.weight',
+				$self->symb(), $env{'user.domain'},
+				$env{'user.name'}, 
+				$env{'request.course.sec'});
+}
+sub part_display {
+    my $self= shift(); my $partID = shift();
+    if (! defined($partID)) { $partID = '0'; }
+    my $display=&Apache::lonnet::EXT('resource.'.$partID.'.display',
+                                     $self->symb);
+    if (! defined($display) || $display eq '') {
+        $display = $partID;
+    }
+    return $display;
+}
+
+# Multiple things need this
+sub getReturnHash {
+    my $self = shift;
+    
+    if (!defined($self->{RETURN_HASH})) {
+        my %tmpHash  = &Apache::lonnet::restore($self->symb());
+        $self->{RETURN_HASH} = \%tmpHash;
+    }
+}       
+
+######
+# Status queries
+######
+
+# These methods query the status of problems.
+
+# If we need to count parts, this function determines the number of
+# parts from the metadata. When called, it returns a reference to a list
+# of strings corresponding to the parts. (Thus, using it in a scalar context
+# tells you how many parts you have in the problem:
+# $partcount = scalar($resource->countParts());
+# Don't use $self->{PARTS} directly because you don't know if it's been
+# computed yet.
+
+=pod
+
+=head2 Resource misc
+
+Misc. functions for the resource.
+
+=over 4
+
+=item * B<hasDiscussion>:
+
+Returns a false value if there has been discussion since the user last
+logged in, true if there has. Always returns false if the discussion
+data was not extracted when the nav map was constructed.
+
+=item * B<last_post_time>:
+
+Returns a false value if there hasn't been discussion otherwise returns
+unix timestamp of last time a discussion posting (or edit) was made.
+
+=item * B<unread_discussion>:
+
+returns in scalar context the count of the number of unread discussion
+postings
+
+returns in list context both the count of postings and a hash ref
+containing the subjects of all unread postings
+
+=item * B<getFeedback>:
+
+Gets the feedback for the resource and returns the raw feedback string
+for the resource, or the null string if there is no feedback or the
+email data was not extracted when the nav map was constructed. Usually
+used like this:
+
+ for (split(/\,/, $res->getFeedback())) {
+    my $link = &Apache::lonnet::escape($_);
+    ...
+
+and use the link as appropriate.
+
+=cut
+
+sub hasDiscussion {
+    my $self = shift;
+    return $self->{NAV_MAP}->hasDiscussion($self->symb());
+}
+
+sub last_post_time {
+    my $self = shift;
+    return $self->{NAV_MAP}->last_post_time($self->symb());
+}
+
+sub unread_discussion {
+    my $self = shift;
+    return $self->{NAV_MAP}->unread_discussion($self->symb());
+}
+
+sub getFeedback {
+    my $self = shift;
+    my $source = $self->src();
+    if ($source =~ /^\/res\//) { $source = substr $source, 5; }
+    return $self->{NAV_MAP}->getFeedback($source);
+}
+
+sub getErrors {
+    my $self = shift;
+    my $source = $self->src();
+    if ($source =~ /^\/res\//) { $source = substr $source, 5; }
+    return $self->{NAV_MAP}->getErrors($source);
+}
+
+=pod
+
+=item * B<parts>():
+
+Returns a list reference containing sorted strings corresponding to
+each part of the problem. Single part problems have only a part '0'.
+Multipart problems do not return their part '0', since they typically
+do not really matter. 
+
+=item * B<countParts>():
+
+Returns the number of parts of the problem a student can answer. Thus,
+for single part problems, returns 1. For multipart, it returns the
+number of parts in the problem, not including psuedo-part 0. 
+
+=item * B<countResponses>():
+
+Returns the total number of responses in the problem a student can answer.
+
+=item * B<responseTypes>():
+
+Returns a hash whose keys are the response types.  The values are the number 
+of times each response type is used.  This is for the I<entire> problem, not 
+just a single part.
+
+=item * B<multipart>():
+
+Returns true if the problem is multipart, false otherwise. Use this instead
+of countParts if all you want is multipart/not multipart.
+
+=item * B<responseType>($part):
+
+Returns the response type of the part, without the word "response" on the
+end. Example return values: 'string', 'essay', 'numeric', etc.
+
+=item * B<responseIds>($part):
+
+Retreives the response IDs for the given part as an array reference containing
+strings naming the response IDs. This may be empty.
+
+=back
+
+=cut
+
+sub parts {
+    my $self = shift;
+
+    if ($self->ext) { return []; }
+
+    $self->extractParts();
+    return $self->{PARTS};
+}
+
+sub countParts {
+    my $self = shift;
+    
+    my $parts = $self->parts();
+
+    # If I left this here, then it's not necessary.
+    #my $delta = 0;
+    #for my $part (@$parts) {
+    #    if ($part eq '0') { $delta--; }
+    #}
+
+    if ($self->{RESOURCE_ERROR}) {
+        return 0;
+    }
+
+    return scalar(@{$parts}); # + $delta;
+}
+
+sub countResponses {
+    my $self = shift;
+    my $count;
+    foreach my $part (@{$self->parts()}) {
+        $count+= scalar($self->responseIds($part));
+    }
+    return $count;
+}
+
+sub responseTypes {
+    my $self = shift;
+    my %responses;
+    foreach my $part (@{$self->parts()}) {
+        foreach my $responsetype ($self->responseType($part)) {
+            $responses{$responsetype}++ if (defined($responsetype));
+        }
+    }
+    return %responses;
+}
+
+sub multipart {
+    my $self = shift;
+    return $self->countParts() > 1;
+}
+
+sub singlepart {
+    my $self = shift;
+    return $self->countParts() == 1;
+}
+
+sub responseType {
+    my $self = shift;
+    my $part = shift;
+
+    $self->extractParts();
+    if (defined($self->{RESPONSE_TYPES}->{$part})) {
+	return @{$self->{RESPONSE_TYPES}->{$part}};
+    } else {
+	return undef;
+    }
+}
+
+sub responseIds {
+    my $self = shift;
+    my $part = shift;
+
+    $self->extractParts();
+    if (defined($self->{RESPONSE_IDS}->{$part})) {
+	return @{$self->{RESPONSE_IDS}->{$part}};
+    } else {
+	return undef;
+    }
+}
+
+# Private function: Extracts the parts information, both part names and
+# part types, and saves it. 
+sub extractParts { 
+    my $self = shift;
+    
+    return if (defined($self->{PARTS}));
+    return if ($self->ext);
+
+    $self->{PARTS} = [];
+
+    my %parts;
+
+    # Retrieve part count, if this is a problem
+    if ($self->is_problem()) {
+	my $partorder = &Apache::lonnet::metadata($self->src(), 'partorder');
+        my $metadata = &Apache::lonnet::metadata($self->src(), 'packages');
+
+	if ($partorder) {
+	    my @parts;
+	    for my $part (split (/,/,$partorder)) {
+		if (!Apache::loncommon::check_if_partid_hidden($part, $self->symb())) {
+		    push @parts, $part;
+		    $parts{$part} = 1;
+		}
+	    }
+	    $self->{PARTS} = \@parts;
+	} else {
+	    if (!$metadata) {
+		$self->{RESOURCE_ERROR} = 1;
+		$self->{PARTS} = [];
+		$self->{PART_TYPE} = {};
+		return;
+	    }
+	    foreach (split(/\,/,$metadata)) {
+		if ($_ =~ /^(?:part|Task)_(.*)$/) {
+		    my $part = $1;
+		    # This floods the logs if it blows up
+		    if (defined($parts{$part})) {
+			&Apache::lonnet::logthis("$part multiply defined in metadata for " . $self->symb());
+		    }
+		    
+		    # check to see if part is turned off.
+		    
+		    if (!Apache::loncommon::check_if_partid_hidden($part, $self->symb())) {
+			$parts{$part} = 1;
+		    }
+		}
+	    }
+	    my @sortedParts = sort keys %parts;
+	    $self->{PARTS} = \@sortedParts;
+        }
+        
+
+        # These hashes probably do not need names that end with "Hash"....
+        my %responseIdHash;
+        my %responseTypeHash;
+
+
+        # Init the responseIdHash
+        foreach (@{$self->{PARTS}}) {
+            $responseIdHash{$_} = [];
+        }
+
+        # Now, the unfortunate thing about this is that parts, part name, and
+        # response id are delimited by underscores, but both the part
+        # name and response id can themselves have underscores in them.
+        # So we have to use our knowlege of part names to figure out 
+        # where the part names begin and end, and even then, it is possible
+        # to construct ambiguous situations.
+        foreach (split /,/, $metadata) {
+            if ($_ =~ /^([a-zA-Z]+)response_(.*)/
+		|| $_ =~ /^(Task)_(.*)/) {
+                my $responseType = $1;
+                my $partStuff = $2;
+                my $partIdSoFar = '';
+                my @partChunks = split /_/, $partStuff;
+                my $i = 0;
+                for ($i = 0; $i < scalar(@partChunks); $i++) {
+                    if ($partIdSoFar) { $partIdSoFar .= '_'; }
+                    $partIdSoFar .= $partChunks[$i];
+                    if ($parts{$partIdSoFar}) {
+                        my @otherChunks = @partChunks[$i+1..$#partChunks];
+                        my $responseId = join('_', @otherChunks);
+                        push @{$responseIdHash{$partIdSoFar}}, $responseId;
+                        push @{$responseTypeHash{$partIdSoFar}}, $responseType;
+                    }
+                }
+            }
+        }
+	my $resorder = &Apache::lonnet::metadata($self->src(),'responseorder');
+        #
+        # Reorder the arrays in the %responseIdHash and %responseTypeHash
+	if ($resorder) {
+	    my @resorder=split(/,/,$resorder);
+	    foreach my $part (keys(%responseIdHash)) {
+		my $i=0;
+		my %resids = map { ($_,$i++) } @{ $responseIdHash{$part} };
+		my @neworder;
+		foreach my $possibleid (@resorder) {
+		    if (exists($resids{$possibleid})) {
+			push(@neworder,$resids{$possibleid});
+		    }
+		}
+		my @ids;
+		my @type;
+		foreach my $element (@neworder) {
+		    push (@ids,$responseIdHash{$part}->[$element]);
+		    push (@type,$responseTypeHash{$part}->[$element]);
+		}
+		$responseIdHash{$part}=\@ids;
+		$responseTypeHash{$part}=\@type;
+	    }
+	}
+        $self->{RESPONSE_IDS} = \%responseIdHash;
+        $self->{RESPONSE_TYPES} = \%responseTypeHash;
+    }
+
+    return;
+}
+
+=pod
+
+=head2 Resource Status
+
+Problem resources have status information, reflecting their various
+dates and completion statuses.
+
+There are two aspects to the status: the date-related information and
+the completion information.
+
+Idiomatic usage of these two methods would probably look something
+like
+
+ foreach ($resource->parts()) {
+    my $dateStatus = $resource->getDateStatus($_);
+    my $completionStatus = $resource->getCompletionStatus($_);
+
+    or
+
+    my $status = $resource->status($_);
+
+    ... use it here ...
+ }
+
+Which you use depends on exactly what you are looking for. The
+status() function has been optimized for the nav maps display and may
+not precisely match what you need elsewhere.
+
+The symbolic constants shown below can be accessed through the
+resource object: C<$res->OPEN>.
+
+=over 4
+
+=item * B<getDateStatus>($part):
+
+($part defaults to 0). A convenience function that returns a symbolic
+constant telling you about the date status of the part. The possible
+return values are:
+
+=back
+
+B<Date Codes>
+
+=over 4
+
+=item * B<OPEN_LATER>:
+
+The problem will be opened later.
+
+=item * B<OPEN>:
+
+Open and not yet due.
+
+
+=item * B<PAST_DUE_ANSWER_LATER>:
+
+The due date has passed, but the answer date has not yet arrived.
+
+=item * B<PAST_DUE_NO_ANSWER>:
+
+The due date has passed and there is no answer opening date set.
+
+=item * B<ANSWER_OPEN>:
+
+The answer date is here.
+
+=item * B<NETWORK_FAILURE>:
+
+The information is unknown due to network failure.
+
+=back
+
+=cut
+
+# Apparently the compiler optimizes these into constants automatically
+sub OPEN_LATER             { return 0; }
+sub OPEN                   { return 1; }
+sub PAST_DUE_NO_ANSWER     { return 2; }
+sub PAST_DUE_ANSWER_LATER  { return 3; }
+sub ANSWER_OPEN            { return 4; }
+sub NOTHING_SET            { return 5; } 
+sub NETWORK_FAILURE        { return 100; }
+
+# getDateStatus gets the date status for a given problem part. 
+# Because answer date, due date, and open date are fully independent
+# (i.e., it is perfectly possible to *only* have an answer date), 
+# we have to completely cover the 3x3 maxtrix of (answer, due, open) x
+# (past, future, none given). This function handles this with a decision
+# tree. Read the comments to follow the decision tree.
+
+sub getDateStatus {
+    my $self = shift;
+    my $part = shift;
+    $part = "0" if (!defined($part));
+
+    # Always return network failure if there was one.
+    return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE});
+
+    my $now = time();
+
+    my $open = $self->opendate($part);
+    my $due = $self->duedate($part);
+    my $answer = $self->answerdate($part);
+
+    if (!$open && !$due && !$answer) {
+        # no data on the problem at all
+        # should this be the same as "open later"? think multipart.
+        return $self->NOTHING_SET;
+    }
+    if (!$open || $now < $open) {return $self->OPEN_LATER}
+    if (!$due || $now < $due) {return $self->OPEN}
+    if ($answer && $now < $answer) {return $self->PAST_DUE_ANSWER_LATER}
+    if ($answer) { return $self->ANSWER_OPEN; }
+    return PAST_DUE_NO_ANSWER;
+}
+
+=pod
+
+B<>
+
+=over 4
+
+=item * B<getCompletionStatus>($part):
+
+($part defaults to 0.) A convenience function that returns a symbolic
+constant telling you about the completion status of the part, with the
+following possible results:
+
+=back
+
+B<Completion Codes>
+
+=over 4
+
+=item * B<NOT_ATTEMPTED>:
+
+Has not been attempted at all.
+
+=item * B<INCORRECT>:
+
+Attempted, but wrong by student.
+
+=item * B<INCORRECT_BY_OVERRIDE>:
+
+Attempted, but wrong by instructor override.
+
+=item * B<CORRECT>:
+
+Correct or correct by instructor.
+
+=item * B<CORRECT_BY_OVERRIDE>:
+
+Correct by instructor override.
+
+=item * B<EXCUSED>:
+
+Excused. Not yet implemented.
+
+=item * B<NETWORK_FAILURE>:
+
+Information not available due to network failure.
+
+=item * B<ATTEMPTED>:
+
+Attempted, and not yet graded.
+
+=back
+
+=cut
+
+sub NOT_ATTEMPTED         { return 10; }
+sub INCORRECT             { return 11; }
+sub INCORRECT_BY_OVERRIDE { return 12; }
+sub CORRECT               { return 13; }
+sub CORRECT_BY_OVERRIDE   { return 14; }
+sub EXCUSED               { return 15; }
+sub ATTEMPTED             { return 16; }
+
+sub getCompletionStatus {
+    my $self = shift;
+    my $part = shift;
+    return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE});
+
+    my $status = $self->queryRestoreHash('solved', $part);
+
+    # Left as separate if statements in case we ever do more with this
+    if ($status eq 'correct_by_student') {return $self->CORRECT;}
+    if ($status eq 'correct_by_scantron') {return $self->CORRECT;}
+    if ($status eq 'correct_by_override') {
+	return $self->CORRECT_BY_OVERRIDE;
+    }
+    if ($status eq 'incorrect_attempted') {return $self->INCORRECT; }
+    if ($status eq 'incorrect_by_override') {return $self->INCORRECT_BY_OVERRIDE; }
+    if ($status eq 'excused') {return $self->EXCUSED; }
+    if ($status eq 'ungraded_attempted') {return $self->ATTEMPTED; }
+    return $self->NOT_ATTEMPTED;
+}
+
+sub queryRestoreHash {
+    my $self = shift;
+    my $hashentry = shift;
+    my $part = shift;
+    $part = "0" if (!defined($part) || $part eq '');
+    return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE});
+
+    $self->getReturnHash();
+
+    return $self->{RETURN_HASH}->{'resource.'.$part.'.'.$hashentry};
+}
+
+=pod
+
+B<Composite Status>
+
+Along with directly returning the date or completion status, the
+resource object includes a convenience function B<status>() that will
+combine the two status tidbits into one composite status that can
+represent the status of the resource as a whole. This method represents
+the concept of the thing we want to display to the user on the nav maps
+screen, which is a combination of completion and open status. The precise logic is
+documented in the comments of the status method. The following results
+may be returned, all available as methods on the resource object
+($res->NETWORK_FAILURE): In addition to the return values that match
+the date or completion status, this function can return "ANSWER_SUBMITTED"
+if that problemstatus parameter value is set to No, suppressing the
+incorrect/correct feedback.
+
+=over 4
+
+=item * B<NETWORK_FAILURE>:
+
+The network has failed and the information is not available.
+
+=item * B<NOTHING_SET>:
+
+No dates have been set for this problem (part) at all. (Because only
+certain parts of a multi-part problem may be assigned, this can not be
+collapsed into "open later", as we do not know a given part will EVER
+be opened. For single part, this is the same as "OPEN_LATER".)
+
+=item * B<CORRECT>:
+
+For any reason at all, the part is considered correct.
+
+=item * B<EXCUSED>:
+
+For any reason at all, the problem is excused.
+
+=item * B<PAST_DUE_NO_ANSWER>:
+
+The problem is past due, not considered correct, and no answer date is
+set.
+
+=item * B<PAST_DUE_ANSWER_LATER>:
+
+The problem is past due, not considered correct, and an answer date in
+the future is set.
+
+=item * B<ANSWER_OPEN>:
+
+The problem is past due, not correct, and the answer is now available.
+
+=item * B<OPEN_LATER>:
+
+The problem is not yet open.
+
+=item * B<TRIES_LEFT>:
+
+The problem is open, has been tried, is not correct, but there are
+tries left.
+
+=item * B<INCORRECT>:
+
+The problem is open, and all tries have been used without getting the
+correct answer.
+
+=item * B<OPEN>:
+
+The item is open and not yet tried.
+
+=item * B<ATTEMPTED>:
+
+The problem has been attempted.
+
+=item * B<ANSWER_SUBMITTED>:
+
+An answer has been submitted, but the student should not see it.
+
+=back
+
+=cut
+
+sub TRIES_LEFT       { return 20; }
+sub ANSWER_SUBMITTED { return 21; }
+sub PARTIALLY_CORRECT{ return 22; }
+
+sub status {
+    my $self = shift;
+    my $part = shift;
+    if (!defined($part)) { $part = "0"; }
+    my $completionStatus = $self->getCompletionStatus($part);
+    my $dateStatus = $self->getDateStatus($part);
+
+    # What we have is a two-dimensional matrix with 4 entries on one
+    # dimension and 5 entries on the other, which we want to colorize,
+    # plus network failure and "no date data at all".
+
+    #if ($self->{RESOURCE_ERROR}) { return NETWORK_FAILURE; }
+    if ($completionStatus == NETWORK_FAILURE) { return NETWORK_FAILURE; }
+
+    my $suppressFeedback = $self->problemstatus($part) eq 'no';
+    # If there's an answer date and we're past it, don't
+    # suppress the feedback; student should know
+    if ($self->duedate($part) && $self->duedate($part) < time() &&
+	$self->answerdate($part) && $self->answerdate($part) < time()) {
+	$suppressFeedback = 0;
+    }
+
+    # There are a few whole rows we can dispose of:
+    if ($completionStatus == CORRECT ||
+        $completionStatus == CORRECT_BY_OVERRIDE ) {
+	if ( $suppressFeedback ) { return ANSWER_SUBMITTED }
+	my $awarded=$self->awarded($part);
+	if ($awarded < 1 && $awarded > 0) {
+            return PARTIALLY_CORRECT;
+	} elsif ($awarded<1) {
+	    return INCORRECT;
+	}
+	return CORRECT; 
+    }
+
+    # If it's WRONG... and not open
+    if ( ($completionStatus == INCORRECT || 
+	  $completionStatus == INCORRECT_BY_OVERRIDE)
+	 && (!$self->opendate($part) ||  $self->opendate($part) > time()) ) {
+	return INCORRECT;
+    }
+
+    if ($completionStatus == ATTEMPTED) {
+        return ATTEMPTED;
+    }
+
+    # If it's EXCUSED, then return that no matter what
+    if ($completionStatus == EXCUSED) {
+        return EXCUSED; 
+    }
+
+    if ($dateStatus == NOTHING_SET) {
+        return NOTHING_SET;
+    }
+
+    # Now we're down to a 4 (incorrect, incorrect_override, not_attempted)
+    # by 4 matrix (date statuses).
+
+    if ($dateStatus == PAST_DUE_ANSWER_LATER ||
+        $dateStatus == PAST_DUE_NO_ANSWER ) {
+        return $suppressFeedback ? ANSWER_SUBMITTED : $dateStatus; 
+    }
+
+    if ($dateStatus == ANSWER_OPEN) {
+        return ANSWER_OPEN;
+    }
+
+    # Now: (incorrect, incorrect_override, not_attempted) x 
+    # (open_later), (open)
+    
+    if ($dateStatus == OPEN_LATER) {
+        return OPEN_LATER;
+    }
+
+    # If it's WRONG...
+    if ($completionStatus == INCORRECT || $completionStatus == INCORRECT_BY_OVERRIDE) {
+        # and there are TRIES LEFT:
+        if ($self->tries($part) < $self->maxtries($part) || !$self->maxtries($part)) {
+            return $suppressFeedback ? ANSWER_SUBMITTED : TRIES_LEFT;
+        }
+        return $suppressFeedback ? ANSWER_SUBMITTED : INCORRECT; # otherwise, return orange; student can't fix this
+    }
+
+    # Otherwise, it's untried and open
+    return OPEN; 
+}
+
+sub CLOSED { return 23; }
+sub ERROR { return 24; }
+
+=pod
+
+B<Simple Status>
+
+Convenience method B<simpleStatus> provides a "simple status" for the resource.
+"Simple status" corresponds to "which icon is shown on the
+Navmaps". There are six "simple" statuses:
+
+=over 4
+
+=item * B<CLOSED>: The problem is currently closed. (No icon shown.)
+
+=item * B<OPEN>: The problem is open and unattempted.
+
+=item * B<CORRECT>: The problem is correct for any reason.
+
+=item * B<INCORRECT>: The problem is incorrect and can still be
+completed successfully.
+
+=item * B<ATTEMPTED>: The problem has been attempted, but the student
+does not know if they are correct. (The ellipsis icon.)
+
+=item * B<ERROR>: There is an error retrieving information about this
+problem.
+
+=back
+
+=cut
+
+# This hash maps the composite status to this simple status, and
+# can be used directly, if you like
+my %compositeToSimple = 
+    (
+      NETWORK_FAILURE()       => ERROR,
+      NOTHING_SET()           => CLOSED,
+      CORRECT()               => CORRECT,
+      PARTIALLY_CORRECT()     => PARTIALLY_CORRECT,
+      EXCUSED()               => CORRECT,
+      PAST_DUE_NO_ANSWER()    => INCORRECT,
+      PAST_DUE_ANSWER_LATER() => INCORRECT,
+      ANSWER_OPEN()           => INCORRECT,
+      OPEN_LATER()            => CLOSED,
+      TRIES_LEFT()            => OPEN,
+      INCORRECT()             => INCORRECT,
+      OPEN()                  => OPEN,
+      ATTEMPTED()             => ATTEMPTED,
+      ANSWER_SUBMITTED()      => ATTEMPTED
+     );
+
+sub simpleStatus {
+    my $self = shift;
+    my $part = shift;
+    my $status = $self->status($part);
+    return $compositeToSimple{$status};
+}
+
+=pod
+
+B<simpleStatusCount> will return an array reference containing, in
+this order, the number of OPEN, CLOSED, CORRECT, INCORRECT, ATTEMPTED,
+and ERROR parts the given problem has.
+
+=cut
+    
+# This maps the status to the slot we want to increment
+my %statusToSlotMap = 
+    (
+     OPEN()      => 0,
+     CLOSED()    => 1,
+     CORRECT()   => 2,
+     INCORRECT() => 3,
+     ATTEMPTED() => 4,
+     ERROR()     => 5
+     );
+
+sub statusToSlot { return $statusToSlotMap{shift()}; }
+
+sub simpleStatusCount {
+    my $self = shift;
+
+    my @counts = (0, 0, 0, 0, 0, 0, 0);
+    foreach my $part (@{$self->parts()}) {
+	$counts[$statusToSlotMap{$self->simpleStatus($part)}]++;
+    }
+
+    return \@counts;
+}
+
+=pod
+
+B<Completable>
+
+The completable method represents the concept of I<whether the student can
+currently do the problem>. If the student can do the problem, which means
+that it is open, there are tries left, and if the problem is manually graded
+or the grade is suppressed via problemstatus, the student has not tried it
+yet, then the method returns 1. Otherwise, it returns 0, to indicate that 
+either the student has tried it and there is no feedback, or that for
+some reason it is no longer completable (not open yet, successfully completed,
+out of tries, etc.). As an example, this is used as the filter for the
+"Uncompleted Homework" option for the nav maps.
+
+If this does not quite meet your needs, do not fiddle with it (unless you are
+fixing it to better match the student's conception of "completable" because
+it's broken somehow)... make a new method.
+
+=cut
+
+sub completable {
+    my $self = shift;
+    if (!$self->is_problem()) { return 0; }
+    my $partCount = $self->countParts();
+
+    foreach my $part (@{$self->parts()}) {
+        if ($part eq '0' && $partCount != 1) { next; }
+        my $status = $self->status($part);
+        # "If any of the parts are open, or have tries left (implies open),
+        # and it is not "attempted" (manually graded problem), it is
+        # not "complete"
+	if ($self->getCompletionStatus($part) == ATTEMPTED() ||
+	    $status == ANSWER_SUBMITTED() ) {
+	    # did this part already, as well as we can
+	    next;
+	}
+	if ($status == OPEN() || $status == TRIES_LEFT()) {
+	    return 1;
+	}
+    }
+        
+    # If all the parts were complete, so was this problem.
+    return 0;
+}
+
+=pod
+
+=head2 Resource/Nav Map Navigation
+
+=over 4
+
+=item * B<getNext>():
+
+Retreive an array of the possible next resources after this
+one. Always returns an array, even in the one- or zero-element case.
+
+=item * B<getPrevious>():
+
+Retreive an array of the possible previous resources from this
+one. Always returns an array, even in the one- or zero-element case.
+
+=cut
+
+sub getNext {
+    my $self = shift;
+    my @branches;
+    my $to = $self->to();
+    foreach my $branch ( split(/,/, $to) ) {
+        my $choice = $self->{NAV_MAP}->getById($branch);
+        #if (!$choice->condition()) { next; }
+        my $next = $choice->goesto();
+        $next = $self->{NAV_MAP}->getById($next);
+
+        push @branches, $next;
+    }
+    return \@branches;
+}
+
+sub getPrevious {
+    my $self = shift;
+    my @branches;
+    my $from = $self->from();
+    foreach my $branch ( split /,/, $from) {
+        my $choice = $self->{NAV_MAP}->getById($branch);
+        my $prev = $choice->comesfrom();
+        $prev = $self->{NAV_MAP}->getById($prev);
+
+        push @branches, $prev;
+    }
+    return \@branches;
+}
+
+sub browsePriv {
+    my $self = shift;
+    if (defined($self->{BROWSE_PRIV})) {
+        return $self->{BROWSE_PRIV};
+    }
+
+    $self->{BROWSE_PRIV} = &Apache::lonnet::allowed('bre',$self->src(),
+						    $self->symb());
+}
+
+=pod
+
+=back
+
+=cut
+
+1;
+
 __END__
+
+