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Diff for /loncom/interface/lonnavmaps.pm between versions 1.15 and 1.224

version 1.15, 2001/09/21 19:56:45 version 1.224, 2003/09/08 19:53:09
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 # The LearningOnline Network with CAPA  # The LearningOnline Network with CAPA
 # Navigate Maps Handler  # Navigate Maps Handler
 #  #
   # $Id$
   #
   # Copyright Michigan State University Board of Trustees
   #
   # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
   #
   # LON-CAPA is free software; you can redistribute it and/or modify
   # it under the terms of the GNU General Public License as published by
   # the Free Software Foundation; either version 2 of the License, or
   # (at your option) any later version.
   #
   # LON-CAPA is distributed in the hope that it will be useful,
   # but WITHOUT ANY WARRANTY; without even the implied warranty of
   # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   # GNU General Public License for more details.
   #
   # You should have received a copy of the GNU General Public License
   # along with LON-CAPA; if not, write to the Free Software
   # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   #
   # /home/httpd/html/adm/gpl.txt
   #
   # http://www.lon-capa.org/
   #
 # (Page Handler  # (Page Handler
 #  #
 # (TeX Content Handler  # (TeX Content Handler
Line 9 Line 33
 # 08/30,08/31,09/06,09/14,09/15,09/16,09/19,09/20,09/21,09/23,  # 08/30,08/31,09/06,09/14,09/15,09/16,09/19,09/20,09/21,09/23,
 # 10/02,10/10,10/14,10/16,10/18,10/19,10/31,11/6,11/14,11/16 Gerd Kortemeyer)  # 10/02,10/10,10/14,10/16,10/18,10/19,10/31,11/6,11/14,11/16 Gerd Kortemeyer)
 #  #
 # 3/1/1,6/1,17/1,29/1,30/1,2/8,9/21 Gerd Kortemeyer  # 3/1/1,6/1,17/1,29/1,30/1,2/8,9/21,9/24,9/25 Gerd Kortemeyer
   # YEAR=2002
   # 1/1 Gerd Kortemeyer
   # Oct-Nov Jeremy Bowers
   # YEAR=2003
   # Jeremy Bowers ... lots of days
   
 package Apache::lonnavmaps;  package Apache::lonnavmaps;
   
 use strict;  use strict;
 use Apache::Constants qw(:common :http);  use Apache::Constants qw(:common :http);
 use Apache::lonnet();  use Apache::loncommon();
 use HTML::TokeParser;  use Apache::lonmenu();
   use POSIX qw (floor strftime);
   use Data::Dumper; # for debugging, not always used
   
   # 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->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       => ''
         );
   # 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 handler {
       my $r = shift;
       real_handler($r);
   }
   
   sub real_handler {
       my $r = shift;
   
       # Handle header-only request
       if ($r->header_only) {
           if ($ENV{'browser.mathml'}) {
               $r->content_type('text/xml');
           } else {
               $r->content_type('text/html');
           }
           $r->send_http_header;
           return OK;
       }
   
       # Send header, don't cache this page
       if ($ENV{'browser.mathml'}) {
           $r->content_type('text/xml');
       } else {
           $r->content_type('text/html');
       }
       &Apache::loncommon::no_cache($r);
       $r->send_http_header;
   
       # 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->print("<html><head>\n");
       $r->print("<title>Navigate Course Contents</title>");
   # ------------------------------------------------------------ Get query string
       &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['register']);
       
   # ----------------------------------------------------- Force menu registration
       my $addentries='';
       if ($ENV{'form.register'}) {
          $addentries=' onLoad="'.&Apache::lonmenu::loadevents().
      '" onUnload="'.&Apache::lonmenu::unloadevents().'"';
          $r->print(&Apache::lonmenu::registerurl(1));
       }
   
       # Header
       $r->print('</head>'.
                 &Apache::loncommon::bodytag('Navigate Course Contents','',
                                       $addentries,'','',$ENV{'form.register'}));
       $r->print('<script>window.focus();</script>');
   
       $r->rflush();
   
       # Check that it's defined
       if (!($navmap->courseMapDefined())) {
           $r->print('<font size="+2" color="red">Coursemap undefined.</font>' .
                     '</body></html>');
           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";
           }
       }
   
       my $jumpToFirstHomework = 0;
       # Check to see if the student is jumping to next open, do-able problem
       if ($ENV{QUERY_STRING} eq '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 {
           $r->print("<a href='navmaps?jumpToFirstHomework'>" .
                     "Go To My First Homework Problem</a>&nbsp;&nbsp;&nbsp;&nbsp;");
       }
   
       my $suppressEmptySequences = 0;
       my $filterFunc = undef;
       my $resource_no_folder_link = 0;
   
       # Display only due homework.
       my $showOnlyHomework = 0;
       if ($ENV{QUERY_STRING} eq 'showOnlyHomework') {
           $showOnlyHomework = 1;
           $suppressEmptySequences = 1;
           $filterFunc = sub { my $res = shift; 
                               return $res->completable() || $res->is_map();
                           };
           $r->print("<p><font size='+2'>Uncompleted Homework</font></p>");
           $ENV{'form.filter'} = '';
           $ENV{'form.condition'} = 1;
    $resource_no_folder_link = 1;
       } else {
           $r->print("<a href='navmaps?showOnlyHomework'>" .
                     "Show Only Uncompleted Homework</a>&nbsp;&nbsp;&nbsp;&nbsp;");
       }
   
       # renderer call
       my $renderArgs = { 'cols' => [0,1,2,3],
                          'url' => '/adm/navmaps',
                          'navmap' => $navmap,
                          'suppressNavmap' => 1,
                          'suppressEmptySequences' => $suppressEmptySequences,
                          'filterFunc' => $filterFunc,
          'resource_no_folder_link' => $resource_no_folder_link,
                          'r' => $r};
       my $render = render($renderArgs);
       $navmap->untieHashes();
   
       # 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'>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>");
           }
       }
   
       $r->print("</body></html>");
       $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.
   # Later, this should add an anchor when we start putting anchors in pages.
   sub getLinkForResource {
       my $stack = shift;
       my $res;
   
       # Check to see if there are any pages in the stack
       foreach $res (@$stack) {
           if (defined($res) && $res->is_page()) {
               return $res->src();
           }
       }
   
       # 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->src();
   }
   
   # Convenience function: This seperates the logic of how to create
   # the problem text strings ("Due: DATE", "Open: DATE", "Not yet assigned",
   # etc.) into a seperate 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 == $res->NETWORK_FAILURE) { 
           return "Having technical difficulties; please check status later"; 
       }
       if ($status == $res->NOTHING_SET) {
           return "Not currently assigned.";
       }
       if ($status == $res->OPEN_LATER) {
           return "Open " . timeToHumanString($res->opendate($part));
       }
       if ($status == $res->OPEN) {
           if ($res->duedate($part)) {
               return "Due " . timeToHumanString($res->duedate($part));
           } else {
               return "Open, no due date";
           }
       }
       if ($status == $res->PAST_DUE_ANSWER_LATER) {
           return "Answer open " . timeToHumanString($res->answerdate($part));
       }
       if ($status == $res->PAST_DUE_NO_ANSWER) {
           return "Was due " . timeToHumanString($res->duedate($part));
       }
       if ($status == $res->ANSWER_OPEN) {
           return "Answer available";
       }
       if ($status == $res->EXCUSED) {
           return "Excused by instructor";
       }
       if ($status == $res->ATTEMPTED) {
           return "Answer submitted, not yet graded.";
       }
       if ($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 ($res->duedate()) {
               return "Due " . timeToHumanString($res->duedate($part)) .
                   " $triesString";
           } else {
               return "No due date $triesString";
           }
       }
       if ($status == $res->ANSWER_SUBMITTED) {
           return 'Answer submitted';
       }
   }
   
   # Convenience function, so others can use it: Is the problem due in less then
   # 24 hours, and still can be done?
   
   sub dueInLessThen24Hours {
       my $res = shift;
       my $part = shift;
       my $status = $res->status($part);
   
       return ($status == $res->OPEN() ||
               $status == $res->TRIES_LEFT()) &&
              $res->duedate() && $res->duedate() < time()+(24*60*60) &&
              $res->duedate() > 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() &&
           $res->duedate() > 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) = @_;
       # zero, '0' and blank are bad times
       if (!$time) {
           return 'never';
       }
   
       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";
           }
   
           # 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/midnight/;
               $timeStr =~ s/12:00 pm/noon/;
               return ($inPast ? "last " : "next ") .
                   $timeStr;
           }
           
           # Is it this year?
           if ( $time[5] == $now[5]) {
               # Return on Month Day, HH:MM meridian
               my $timeStr = strftime("on %A, %b %e at %I:%M %P", localtime($time));
               $timeStr =~ s/12:00 am/midnight/;
               $timeStr =~ s/12:00 pm/noon/;
               return $timeStr;
           }
   
           # Not this year, so show the year
           my $timeStr = strftime("on %A, %b %e %G at %I:%M %P", localtime($time));
           $timeStr =~ s/12:00 am/midnight/;
           $timeStr =~ s/12:00 pm/noon/;
           return $timeStr;
       }
   }
   
   
   =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.
   
   =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; }
   
   # Data for render_resource
   
   sub render_resource {
       my ($resource, $part, $params) = @_;
   
       my $nonLinkedText = ''; # stuff after resource title not in link
   
       my $link = $params->{"resourceLink"};
       my $src = $resource->src();
       my $it = $params->{"iterator"};
       my $filter = $it->{FILTER};
   
       my $title = $resource->compTitle();
       if ($src =~ /^\/uploaded\//) {
           $nonLinkedText=$title;
           $title = '';
       }
       my $partLabel = "";
       my $newBranchText = "";
       
       # If this is a new branch, label it so
       if ($params->{'isNewBranch'}) {
           $newBranchText = "<img src='/adm/lonIcons/branch.gif' border='0' />";
       }
   
       # links to open and close the folder
       my $linkopen = "<a href='$link'>";
       my $linkclose = "</a>";
   
       # Default icon: unknown page
       my $icon = "<img src='/adm/lonIcons/unknown.gif' alt='' border='0' />";
       
       if ($resource->is_problem()) {
           if ($part eq '0' || $params->{'condensed'}) {
               $icon = '<img src="/adm/lonIcons/problem.gif" alt="" border="0" />';
           } else {
               $icon = $params->{'indentString'};
           }
       } else {
    my $curfext= (split (/\./,$resource->src))[-1];
    my $embstyle = &Apache::loncommon::fileembstyle($curfext);
    # The unless conditional that follows is a bit of overkill
    if (!(!defined($embstyle) || $embstyle eq 'unk' || $embstyle eq 'hdn')) {
       $icon = "<img src='/adm/lonIcons/$curfext.gif' alt='' 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';
   
           if (!$params->{'resource_no_folder_link'}) {
               $icon = "navmap.$folderType." . ($nowOpen ? 'closed' : 'open') . '.gif';
               $icon = "<img src='/adm/lonIcons/$icon' alt='' 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';
               $icon = "<img src='/adm/lonIcons/$icon' alt='' border='0' />";
   
               $linkopen = "";
               $linkclose = "";
           }
       }
   
       if ($resource->randomout()) {
           $nonLinkedText .= ' <i>(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'}) {
           $partLabel = " (Part $part)";
           $title = "";
       }
   
       if ($params->{'condensed'} && $resource->countParts() > 1) {
           $nonLinkedText .= ' (' . $resource->countParts() . ' parts)';
       }
   
       if (!$params->{'resource_nolink'} && $src !~ /^\/uploaded\// &&
    !$resource->is_sequence()) {
           $result .= "  $curMarkerBegin<a href='$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 $linkopen = "<a href='$link'>";
       my $linkclose = "</a>";
   
       if ($resource->hasDiscussion()) {
           $discussionHTML = $linkopen .
               '<img border="0" src="/adm/lonMisc/chat.gif" />' .
               $linkclose;
       }
       
       if ($resource->getFeedback()) {
           my $feedback = $resource->getFeedback();
           foreach (split(/\,/, $feedback)) {
               if ($_) {
                   $feedbackHTML .= '&nbsp;<a href="/adm/email?display='
                       . &Apache::lonnet::escape($_) . '">'
                       . '<img src="/adm/lonMisc/feedback.gif" '
                       . 'border="0" /></a>';
               }
           }
       }
       
       if ($resource->getErrors()) {
           my $errors = $resource->getErrors();
           foreach (split(/,/, $errors)) {
               if ($_) {
                   $errorHTML .= '&nbsp;<a href="/adm/email?display='
                       . &Apache::lonnet::escape($_) . '">'
                       . '<img src="/adm/lonMisc/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 $linkopen = "<a href='$link'>";
       my $linkclose = "</a>";
   
       if ($resource->is_problem() &&
           !$firstDisplayed) {
   
           my $icon = $statusIconMap{$resource->simpleStatus($part)};
           my $alt = $iconAltTags{$icon};
           if ($icon) {
               $result .= "<td width='30' valign='center' width='50' align='right'>$linkopen<img width='25' height='25' src='/adm/lonIcons/$icon' border='0' alt='$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 (dueInLessThen24Hours($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;
   }
   
   my @preparedColumns = (\&render_resource, \&render_communication_status,
                          \&render_quick_status, \&render_long_status);
   
   sub setDefault {
       my ($val, $default) = @_;
       if (!defined($val)) { return $default; }
       return $val;
   }
   
   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 $mustCloseNavMap = 0;
       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 $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();
               $mustCloseNavMap = 1;
           }
   
           # 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'}) {
               $here = $jump = $ENV{'form.postsymb'};
           } elsif ($ENV{'form.postdata'}) {
               # 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);
           }
   
           # 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 (($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();
               $mustCloseNavMap = 1;
           }
   
           # 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;
           $result.='<tr><td align="right" valign="bottom">Key:&nbsp;&nbsp;</td>';
           if ($navmap->{LAST_CHECK}) {
               $result .= 
                   '<img src="/adm/lonMisc/chat.gif"> New discussion since '.
                   strftime("%A, %b %e at %I:%M %P", localtime($navmap->{LAST_CHECK})).
                   '</td><td align="center" valign="bottom">&nbsp;&nbsp;'.
                   '<img src="/adm/lonMisc/feedback.gif"> New message (click to open)<p>'.
                   '</td>'; 
           } else {
               $result .= '<td align="center" valign="bottom">&nbsp;&nbsp;'.
                   '<img src="/adm/lonMisc/chat.gif"> Discussions</td><td align="center" valign="bottom">'.
                   '&nbsp;&nbsp;<img src="/adm/lonMisc/feedback.gif"> New message (click to open)'.
                   '</td>'; 
           }
   
           $result .= '</tr></table>';
       }
   
       if ($printCloseAll && !$args->{'resource_no_folder_link'}) {
           if ($condition) {
               $result.="<a href=\"navmaps?condition=0&filter=&$queryString" .
                   "&here=" . Apache::lonnet::escape($here) .
                   "\">Close All Folders</a>";
           } else {
               $result.="<a href=\"navmaps?condition=1&filter=&$queryString" .
                   "&here=" . Apache::lonnet::escape($here) . 
                   "\">Open All Folders</a>";
           }
           $result .= "<br /><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;    
       $args->{'indentString'} = setDefault($args->{'indentString'}, "<img src='/adm/lonIcons/whitespace1.gif' width='25' height='1' alt='' 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;
   
       $args->{'indentLevel'} = -1; # first BEGIN_MAP takes this to 0
       while ($curRes = $it->next()) {
           # Maintain indentation level.
           if ($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 ($condenseParts) { # do the condensation
                   if (!$curRes->opendate("0")) {
                       @parts = ();
                       $args->{'condensed'} = 1;
                   }
                   if (!$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';
           }
   
           # 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};
               my $stack = $it->getStack();
               my $src = getLinkForResource($stack);
               
               my $srcHasQuestion = $src =~ /\?/;
               $args->{"resourceLink"} = $src.
                   ($srcHasQuestion?'&':'?') .
                   'symb=' . &Apache::lonnet::escape($curRes->symb());
               
               # 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()) {
    Apache::lonnet::logthis("navmaps 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>setTimeout(\"location += '#curloc';\", 0)</script>\n";
       }
   
       $result .= "</table>";
       
       if ($r) {
           $r->print($result);
           $result = "";
           $r->rflush();
       }
           
       if ($mustCloseNavMap) { $navmap->untieHashes(); } 
   
       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>, B<Url> or B<MapPc>. 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 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.
   
   =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
   
   When you are done with the $navmap object, you I<must> call 
   $navmap->untieHashes(), or you'll prevent the current user from using that 
   course until the web server is restarted. (!)
   
   =head2 Methods
   
   =over 4
   
   =item * B<getIterator>(first, finish, filter, condition):
   
   See iterator documentation below.
   
   =cut
   
   use strict;
 use GDBM_File;  use GDBM_File;
   
 # -------------------------------------------------------------- Module Globals  sub new {
 my %hash;      # magic invocation to create a class instance
 my @rows;      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;
 # These cache hashes need to be independent of user, resource and course      $self->{PARM_HASH} = \%parmhash;
 # (user and course can/should be in the keys)      $self->{PARM_CACHE} = {};
 #  
   
 my %courserdatas;      bless($self);
 my %userrdatas;          
       return $self;
   }
   
 #  sub generate_course_user_opt {
 # These global hashes are dependent on user, course and resource,       my $self = shift;
 # and need to be initialized every time when a sheet is calculated      if ($self->{COURSE_USER_OPT_GENERATED}) { return; }
 #  
 my %courseopt;  
 my %useropt;  
 my %parmhash;  
   
       my $uname=$ENV{'user.name'};
       my $udom=$ENV{'user.domain'};
       my $uhome=$ENV{'user.home'};
       my $cid=$ENV{'request.course.id'};
       my $chome=$ENV{'course.'.$cid.'.home'};
       my ($cdom,$cnum)=split(/\_/,$cid);
       
       my $userprefix=$uname.'_'.$udom.'_';
       
       my %courserdatas; my %useropt; my %courseopt; my %userrdatas;
       unless ($uhome eq 'no_host') { 
   # ------------------------------------------------- Get coursedata (if present)
    unless ((time-$courserdatas{$cid.'.last_cache'})<240) {
       my $reply=&Apache::lonnet::reply('dump:'.$cdom.':'.$cnum.
        ':resourcedata',$chome);
       # Check for network failure
       if ( $reply =~ /no.such.host/i || $reply =~ /con_lost/i) {
    $self->{NETWORK_FAILURE} = 1;
       } elsif ($reply!~/^error\:/) {
    $courserdatas{$cid}=$reply;
    $courserdatas{$cid.'.last_cache'}=time;
       }
    }
    foreach (split(/\&/,$courserdatas{$cid})) {
       my ($name,$value)=split(/\=/,$_);
       $courseopt{$userprefix.&Apache::lonnet::unescape($name)}=
    &Apache::lonnet::unescape($value);
    }
   # --------------------------------------------------- Get userdata (if present)
    unless ((time-$userrdatas{$uname.'___'.$udom.'.last_cache'})<240) {
       my $reply=&Apache::lonnet::reply('dump:'.$udom.':'.$uname.':resourcedata',$uhome);
       if ($reply!~/^error\:/) {
    $userrdatas{$uname.'___'.$udom}=$reply;
    $userrdatas{$uname.'___'.$udom.'.last_cache'}=time;
       }
       # check to see if network failed
       elsif ( $reply=~/no.such.host/i || $reply=~/con.*lost/i )
       {
    $self->{NETWORK_FAILURE} = 1;
       }
    }
    foreach (split(/\&/,$userrdatas{$uname.'___'.$udom})) {
       my ($name,$value)=split(/\=/,$_);
       $useropt{$userprefix.&Apache::lonnet::unescape($name)}=
    &Apache::lonnet::unescape($value);
    }
    $self->{COURSE_OPT} = \%courseopt;
    $self->{USER_OPT} = \%useropt;
       }
   
 # ------------------------------------------------------------------ Euclid gcd      $self->{COURSE_USER_OPT_GENERATED} = 1;
       
       return;
   }
   
 sub euclid {  sub generate_email_discuss_status {
     my ($e,$f)=@_;      my $self = shift;
     my $a; my $b; my $r;      if ($self->{EMAIL_DISCUSS_GENERATED}) { return; }
     if ($e>$f) { $b=$e; $r=$f; } else { $r=$e; $b=$f; }  
     while ($r!=0) {      my $cid=$ENV{'request.course.id'};
  $a=$b; $b=$r;      my ($cdom,$cnum)=split(/\_/,$cid);
         $r=$a%$b;      
       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 %feedback=();
       my %error=();
       my $keys = &Apache::lonnet::reply('keys:'.
         $ENV{'user.domain'}.':'.
         $ENV{'user.name'}.':nohist_email',
         $ENV{'user.home'});
       
       foreach my $msgid (split(/\&/, $keys)) {
    $msgid=&Apache::lonnet::unescape($msgid);
    my $plain=&Apache::lonnet::unescape(&Apache::lonnet::unescape($msgid));
    if ($plain=~/(Error|Feedback) \[([^\]]+)\]/) {
       my ($what,$url)=($1,$2);
       my %status=
    &Apache::lonnet::get('email_status',[$msgid]);
       if ($status{$msgid}=~/^error\:/) { 
    $status{$msgid}=''; 
       }
       
       if (($status{$msgid} eq 'new') || 
    (!$status{$msgid})) { 
    if ($what eq 'Error') {
       $error{$url}.=','.$msgid; 
    } else {
       $feedback{$url}.=','.$msgid;
    }
       }
    }
     }      }
     return $b;      
       $self->{FEEDBACK} = \%feedback;
       $self->{ERROR_MSG} = \%error; # what is this? JB
       $self->{DISCUSSION_TIME} = \%discussiontime;
       $self->{EMAIL_STATUS} = \%emailstatus;
       
       $self->{EMAIL_DISCUSS_GENERATED} = 1;
 }  }
   
 # --------------------------------------------------------------------- Parmval  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;
   
 # -------------------------------------------- Figure out a cascading parameter      $self->{RETRIEVED_USER_DATA} = 1;
 #  }
 # For this function to work  
 #  # Internal function: Takes a key to look up in the nav hash and implements internal
 # * parmhash needs to be tied  # memory caching of that key.
 # * courseopt and useropt need to be initialized for this user and course  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);
       return $iterator;
   }
   
   # unties the hash when done
   sub untieHashes {
       my $self = shift;
       untie %{$self->{NAV_HASH}};
       untie %{$self->{PARM_HASH}};
   }
   
   # 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});
       return $self->{DISCUSSION_TIME}->{$symb} >
              $self->{LAST_CHECK};
   }
   
   # 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) = split (/___/, $symb);
       my $map = $self->getResourceByUrl($mapUrl);
       return $self->getById($map->map_pc() . '.' . $id);
   }
   
   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 {  sub parmval {
       my $self = shift;
     my ($what,$symb)=@_;      my ($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 $cid=$ENV{'request.course.id'};
     my $csec=$ENV{'request.course.sec'};      my $csec=$ENV{'request.course.sec'};
     my $uname=$ENV{'user.name'};      my $uname=$ENV{'user.name'};
Line 76  sub parmval { Line 1984  sub parmval {
     my ($mapname,$id,$fn)=split(/\_\_\_/,$symb);      my ($mapname,$id,$fn)=split(/\_\_\_/,$symb);
   
 # ----------------------------------------------------- Cascading lookup scheme  # ----------------------------------------------------- Cascading lookup scheme
        my $rwhat=$what;      my $rwhat=$what;
        $what=~s/^parameter\_//;      $what=~s/^parameter\_//;
        $what=~s/\_/\./;      $what=~s/\_/\./;
   
        my $symbparm=$symb.'.'.$what;      my $symbparm=$symb.'.'.$what;
        my $mapparm=$mapname.'___(all).'.$what;      my $mapparm=$mapname.'___(all).'.$what;
        my $usercourseprefix=$uname.'_'.$udom.'_'.$cid;      my $usercourseprefix=$uname.'_'.$udom.'_'.$cid;
   
        my $seclevel=      my $seclevel= $usercourseprefix.'.['.$csec.'].'.$what;
             $usercourseprefix.'.['.      my $seclevelr=$usercourseprefix.'.['.$csec.'].'.$symbparm;
  $csec.'].'.$what;      my $seclevelm=$usercourseprefix.'.['.$csec.'].'.$mapparm;
        my $seclevelr=  
             $usercourseprefix.'.['.      my $courselevel= $usercourseprefix.'.'.$what;
  $csec.'].'.$symbparm;      my $courselevelr=$usercourseprefix.'.'.$symbparm;
        my $seclevelm=      my $courselevelm=$usercourseprefix.'.'.$mapparm;
             $usercourseprefix.'.['.  
  $csec.'].'.$mapparm;      my $useropt = $self->{USER_OPT};
       my $courseopt = $self->{COURSE_OPT};
        my $courselevel=      my $parmhash = $self->{PARM_HASH};
             $usercourseprefix.'.'.$what;  
        my $courselevelr=  # ---------------------------------------------------------- first, check user
             $usercourseprefix.'.'.$symbparm;      if ($uname and defined($useropt)) {
        my $courselevelm=          if (defined($$useropt{$courselevelr})) { return $$useropt{$courselevelr}; }
             $usercourseprefix.'.'.$mapparm;          if (defined($$useropt{$courselevelm})) { return $$useropt{$courselevelm}; }
           if (defined($$useropt{$courselevel})) { return $$useropt{$courselevel}; }
 # ---------------------------------------------------------- fourth, check user      }
         
       if ($uname) {   # ------------------------------------------------------- second, check course
       if ($csec and defined($courseopt)) {
        if ($useropt{$courselevelr}) { return $useropt{$courselevelr}; }          if (defined($$courseopt{$seclevelr})) { return $$courseopt{$seclevelr}; }
           if (defined($$courseopt{$seclevelm})) { return $$courseopt{$seclevelm}; }
        if ($useropt{$courselevelm}) { return $useropt{$courselevelm}; }          if (defined($$courseopt{$seclevel})) { return $$courseopt{$seclevel}; }
       }
        if ($useropt{$courselevel}) { return $useropt{$courselevel}; }  
   
       }  
   
 # --------------------------------------------------------- third, check course  
        
        if ($csec) {  
    
         if ($courseopt{$seclevelr}) { return $courseopt{$seclevelr}; }  
   
         if ($courseopt{$seclevelm}) { return $courseopt{$seclevelm}; }    
   
         if ($courseopt{$seclevel}) { return $courseopt{$seclevel}; }  
     
       }  
   
        if ($courseopt{$courselevelr}) { return $courseopt{$courselevelr}; }  
   
        if ($courseopt{$courselevelm}) { return $courseopt{$courselevelm}; }  
   
        if ($courseopt{$courselevel}) { return $courseopt{$courselevel}; }  
   
 # ----------------------------------------------------- second, check map parms  
   
        my $thisparm=$parmhash{$symbparm};  
        if ($thisparm) { return $thisparm; }  
   
 # -------------------------------------------------------- first, check default  
   
        return &Apache::lonnet::metadata($fn,$rwhat.'.default');  
           
 }  
   
   
   
 # ------------------------------------------------------------- Find out status  
   
 sub astatus {  
     my $rid=shift;  
     my $code=1;  
     my $ctext='';  
     $rid=~/(\d+)\.(\d+)/;  
     my $symb=&Apache::lonnet::declutter($hash{'map_id_'.$1}).'___'.$2.'___'.  
      &Apache::lonnet::declutter($hash{'src_'.$rid});  
   
     my %duedate=();  
     my %opendate=();  
     my %answerdate=();  
     map {  
         if ($_=~/^parameter\_(.*)\_opendate$/) {  
     my $part=$1;  
             $duedate{$part}=&parmval($part.'.duedate',$symb);  
             $opendate{$part}=&parmval($part.'.opendate',$symb);  
             $answerdate{$part}=&parmval($part.'.answerdate',$symb);  
         }  
     } sort split(/\,/,&Apache::lonnet::metadata($hash{'src_'.$rid},'keys'));  
   
     my $duedate=&parmval('0.duedate',$symb);  
     my $opendate=&parmval('0.opendate',$symb);  
     my $answerdate=&parmval('0.answerdate',$symb);  
     my $now=time;  
     my $tcode=0;  
    if ($opendate) {  
     if ($now<$duedate) {  
         $tcode=2;   
         $ctext='Due: '.localtime($duedate);  
         if ($now<$opendate) {   
           $tcode=1;   
           $ctext='Open: '.localtime($opendate);  
         }  
         if ($duedate-$now<86400) {  
    $tcode=4;  
            $ctext='Due: '.localtime($duedate);  
         }  
      } else {  
        $tcode=3;  
        if ($now<$answerdate) {    
           $ctext='Answer: '.localtime($duedate);  
        }  
     }  
    } else {  
     $tcode=1;  
    }  
     my $answer=&Apache::lonnet::reply(  
               "restore:$ENV{'user.domain'}:$ENV{'user.name'}:".  
               $ENV{'request.course.id'}.':'.  
               &Apache::lonnet::escape($symb),  
               "$ENV{'user.home'}");  
     my %returnhash=();  
     map {  
  my ($name,$value)=split(/\=/,$_);  
         $returnhash{&Apache::lonnet::unescape($name)}=  
                     &Apache::lonnet::unescape($value);  
     } split(/\&/,$answer);  
     if ($returnhash{'version'}) {  
        my $version;  
        for ($version=1;$version<=$returnhash{'version'};$version++) {  
           map {  
              $returnhash{$_}=$returnhash{$version.':'.$_};  
           } split(/\:/,$returnhash{$version.':keys'});  
        }  
        map {  
            if (($_=~/\.(\w+)\.solved$/) && ($_!~/^\d+\:/)) {  
                my $part=$1;  
                if ($ctext) { $ctext.=', '; }  
                if ($part) {  
    $ctext.='Part '.$part.': ';  
                }  
        if ($returnhash{$_} eq 'correct_by_student') {  
                    unless ($code==2) { $code=3; }  
                    $ctext.='solved';  
                } elsif ($returnhash{$_} eq 'correct_by_override') {  
                    unless ($code==2) { $code=3; }  
                    $ctext.='override';  
                } elsif ($returnhash{$_} eq 'incorrect_attempted') {  
                    $code=2;  
                    $ctext.=  
                      $returnhash{'resource.'.$part.'.tries'}.'/'.  
                      &parmval($part.'.maxtries',$symb).' tries';  
                } elsif ($returnhash{$_} eq 'incorrect_by_override') {  
                    $code=2;  
                    $ctext.='override';  
                } elsif ($returnhash{$_} eq 'excused') {  
                    unless ($code==2) { $code=3; }  
                    $ctext.='excused';  
                }  
            }  
        } keys %returnhash;  
     }  
     return 'p'.$code.$tcode.'"'.$ctext.'"';  
 }  
   
 # ------------------------------------------------------------ Build page table  
   
 sub tracetable {  
     my ($sofar,$rid,$beenhere)=@_;  
     my $further=$sofar;  
     unless ($beenhere=~/\&$rid\&/) {  
        $beenhere.=$rid.'&';    
   
        if (defined($hash{'is_map_'.$rid})) {  
            $sofar++;  
            my $tprefix='';  
            if ($hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$rid}}}   
             eq 'sequence') {   
                $tprefix='h';   
            }  
            if (defined($rows[$sofar])) {  
               $rows[$sofar].='&'.$tprefix.$rid;  
            } else {  
               $rows[$sofar]=$tprefix.$rid;  
            }  
            if ((defined($hash{'map_start_'.$hash{'src_'.$rid}})) &&  
                (defined($hash{'map_finish_'.$hash{'src_'.$rid}})) &&  
                ($tprefix eq 'h')) {  
               my $frid=$hash{'map_finish_'.$hash{'src_'.$rid}};  
       $sofar=  
                 &tracetable($sofar,$hash{'map_start_'.$hash{'src_'.$rid}},  
                 '&'.$frid.'&');  
               $sofar++;  
               if ($hash{'src_'.$frid}) {  
                my $brepriv=&Apache::lonnet::allowed('bre',$hash{'src_'.$frid});  
                if (($brepriv eq '2') || ($brepriv eq 'F')) {  
  my $pprefix='';  
                  if ($hash{'src_'.$frid}=~  
                                  /\.(problem|exam|quiz|assess|survey|form)$/) {  
      $pprefix=&astatus($frid);  
   
                  }  
                  if (defined($rows[$sofar])) {  
                    $rows[$sofar].='&'.$pprefix.$frid;  
                  } else {  
                    $rows[$sofar]=$pprefix.$frid;  
                  }  
        }  
       }  
    }  
        } else {  
           $sofar++;  
           if ($hash{'src_'.$rid}) {  
            my $brepriv=&Apache::lonnet::allowed('bre',$hash{'src_'.$rid});  
            if (($brepriv eq '2') || ($brepriv eq 'F')) {  
      my $pprefix='';  
              if ($hash{'src_'.$rid}=~  
                                  /\.(problem|exam|quiz|assess|survey|form)$/) {  
          $pprefix=&astatus($rid);  
              }  
              if (defined($rows[$sofar])) {  
                 $rows[$sofar].='&'.$pprefix.$rid;  
              } else {  
                $rows[$sofar]=$pprefix.$rid;  
              }  
    }  
           }  
        }  
   
        if (defined($hash{'to_'.$rid})) {  
   my $mincond=1;  
           my $next='';  
           map {  
               my $thiscond=  
       &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});  
               if ($thiscond>=$mincond) {  
   if ($next) {  
       $next.=','.$_.':'.$thiscond;  
                   } else {  
                       $next=$_.':'.$thiscond;  
   }  
                   if ($thiscond>$mincond) { $mincond=$thiscond; }  
       }  
           } split(/\,/,$hash{'to_'.$rid});  
           map {  
               my ($linkid,$condval)=split(/\:/,$_);  
               if ($condval>=$mincond) {  
                 my $now=&tracetable($sofar,$hash{'goesto_'.$linkid},$beenhere);  
                 if ($now>$further) { $further=$now; }  
       }  
           } split(/\,/,$next);  
   
        }      if (defined($courseopt)) {
           if (defined($$courseopt{$courselevelr})) { return $$courseopt{$courselevelr}; }
           if (defined($$courseopt{$courselevelm})) { return $$courseopt{$courselevelm}; }
           if (defined($$courseopt{$courselevel})) { return $$courseopt{$courselevel}; }
     }      }
     return $further;  
   # ----------------------------------------------------- third, check map parms
   
       my $thisparm=$$parmhash{$symbparm};
       if (defined($thisparm)) { return $thisparm; }
   
   # ----------------------------------------------------- fourth , check default
   
       my $default=&Apache::lonnet::metadata($fn,$rwhat.'.default');
       if (defined($default)) { return $default}
   
   # --------------------------------------------------- fifth , 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 '';
 }  }
   
 # ================================================================ Main Handler  =pod
   
 sub handler {  =item * B<getResourceByUrl>(url):
   my $r=shift;  
   
   Retrieves a resource object by URL of the resource. 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. As a result, this is probably useful only for maps.
   
   =item * B<retrieveResources>(map, filterFunc, recursive, bailout):
   
   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. 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. 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<hasResources>(map, filterFunc, recursive):
   
   Convience method for
   
    scalar(retrieveResources($map, $filterFunc, $recursive, 1)) > 0
   
   which will tell whether the map has resources matching the description
   in the filter function.
   
   =cut
   
   sub getResourceByUrl {
       my $self = shift;
       my $resUrl = shift;
   
       if (ref($resUrl)) { return $resUrl; }
   
       $resUrl = &Apache::lonnet::clutter($resUrl);
       my $resId = $self->{NAV_HASH}->{'ids_' . $resUrl};
       if ($resId =~ /,/) {
           $resId = (split (/,/, $resId))[0];
       }
       if (!$resId) { return ''; }
       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; }
   
       # Create the necessary iterator.
       if (!ref($map)) { # assume it's a url of a map.
           $map = $self->getResourceByUrl($map);
       }
   
 # ------------------------------------------- Set document type for header only      # If nothing was passed, assume top-level map
       if (!$map) {
    $map = $self->getById('0.0');
       }
   
   if ($r->header_only) {      # Check the map's validity.
        if ($ENV{'browser.mathml'}) {      if (!$map->is_map()) {
            $r->content_type('text/xml');          # Oh, to throw an exception.... how I'd love that!
        } else {          return ();
            $r->content_type('text/html');      }
        }  
        $r->send_http_header;  
        return OK;  
    }  
   
   my $requrl=$r->uri;  
 # ----------------------------------------------------------------- Tie db file  
   if ($ENV{'request.course.fn'}) {  
       my $fn=$ENV{'request.course.fn'};  
       if (-e "$fn.db") {  
           if ((tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER,0640)) &&  
              (tie(%parmhash,'GDBM_File',  
            $ENV{'request.course.fn'}.'_parms.db',&GDBM_READER,0640))) {  
 # ------------------------------------------------------------------- Hash tied  
               my $firstres=$hash{'map_start_/res/'.$ENV{'request.course.uri'}};  
               my $lastres=$hash{'map_finish_/res/'.$ENV{'request.course.uri'}};  
               if (($firstres) && ($lastres)) {  
 # ----------------------------------------------------------------- Render page  
 # -------------------------------------------------------------- Set parameters  
   
   
 # ---------------------------- initialize coursedata and userdata for this user  
     undef %courseopt;  
     undef %useropt;  
   
     my $uname=$ENV{'user.name'};      # Get an iterator.
     my $udom=$ENV{'user.domain'};      my $it = $self->getIterator($map->map_start(), $map->map_finish(),
     my $uhome=$ENV{'user.home'};                                  undef, $recursive);
     my $cid=$ENV{'request.course.id'};  
     my $chome=$ENV{'course.'.$cid.'.home'};      my @resources = ();
     my ($cdom,$cnum)=split(/\_/,$cid);  
       # 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;
               }
           }
   
     my $userprefix=$uname.'_'.$udom.'_';      }
   
     unless ($uhome eq 'no_host') {       return @resources;
 # -------------------------------------------------------------- Get coursedata  }
       unless  
         ((time-$courserdatas{$cid.'.last_cache'})<240) {  sub hasResource {
          my $reply=&Apache::lonnet::reply('dump:'.$cdom.':'.$cnum.      my $self = shift;
               ':resourcedata',$chome);      my $map = shift;
          if ($reply!~/^error\:/) {      my $filterFunc = shift;
             $courserdatas{$cid}=$reply;      my $recursive = shift;
             $courserdatas{$cid.'.last_cache'}=time;      
          }      return scalar($self->retrieveResources($map, $filterFunc, $recursive, 1)) > 0;
       }  }
       map {  
          my ($name,$value)=split(/\=/,$_);  1;
          $courseopt{$userprefix.&Apache::lonnet::unescape($name)}=  
                     &Apache::lonnet::unescape($value);  package Apache::lonnavmaps::iterator;
       } split(/\&/,$courserdatas{$cid});  
 # --------------------------------------------------- Get userdata (if present)  =pod
       unless  
         ((time-$userrdatas{$uname.'___'.$udom.'.last_cache'})<240) {  =back
          my $reply=  
        &Apache::lonnet::reply('dump:'.$udom.':'.$uname.':resourcedata',$uhome);  =head1 Object: navmap Iterator
          if ($reply!~/^error\:/) {  
      $userrdatas{$uname.'___'.$udom}=$reply;  An I<iterator> encapsulates the logic required to traverse a data
      $userrdatas{$uname.'___'.$udom.'.last_cache'}=time;  structure. navmap uses an iterator to traverse the course map
          }  according to the criteria you wish to use.
       }  
       map {  To obtain an iterator, call the B<getIterator>() function of a
          my ($name,$value)=split(/\=/,$_);  B<navmap> object. (Do not instantiate Apache::lonnavmaps::iterator
          $useropt{$userprefix.&Apache::lonnet::unescape($name)}=  directly.) This will return a reference to the iterator:
           &Apache::lonnet::unescape($value);  
       } split(/\&/,$userrdatas{$uname.'___'.$udom});  C<my $resourceIterator = $navmap-E<gt>getIterator();>
     }  
   To get the next thing from the iterator, call B<next>:
                   @rows=();  
   C<my $nextThing = $resourceIterator-E<gt>next()>
                   &tracetable(0,$firstres,'&'.$lastres.'&');  
                   if ($hash{'src_'.$lastres}) {  getIterator behaves as follows:
                      my $brepriv=  
                         &Apache::lonnet::allowed('bre',$hash{'src_'.$lastres});  =over 4
                      if (($brepriv eq '2') || ($brepriv eq 'F')) {  
                         $rows[$#rows+1]=''.$lastres;  =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
 # ------------------------------------------------------------------ Page parms  navmap->firstResource() for the corresponding nav map. finishResource
   corresponds to where you want the iterator to end, defaulting to
                   my $j;  navmap->finishResource(). filterHash is a hash used as a set
                   my $i;  containing strings representing the resource IDs, defaulting to
                   my $lcm=1;  empty. Condition is a 1 or 0 that sets what to do with the filter
                   my $contents=0;  hash: If a 0, then only resources that exist IN the filterHash will be
   recursed on. If it is a 1, only resources NOT in the filterHash will
 # ---------------------------------------------- Go through table to get layout  be recursed on. Defaults to 0. forceTop is a boolean value. If it is
   false (default), the iterator will only return the first level of map
                   for ($i=0;$i<=$#rows;$i++) {  that is not just a single, 'redirecting' map. If true, the iterator
      if ($rows[$i]) {  will return all information, starting with the top-level map,
       $contents++;  regardless of content. returnTopMap, if true (default false), will
                       my @colcont=split(/\&/,$rows[$i]);  cause the iterator to return the top-level map object (resource 0.0)
                       $lcm*=($#colcont+1)/euclid($lcm,($#colcont+1));  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
   
                   unless ($contents) {  The tokens are retreivable via methods on the iterator object, i.e.,
                       $r->content_type('text/html');  $iterator->END_MAP.
                       $r->send_http_header;  
                       $r->print('<html><body>Empty Map.</body></html>');  
                   } else {  
   
 # ------------------------------------------------------------------ Build page  
   
       my $currenturl=$ENV{'form.postdata'};  
                       $currenturl=~s/^http\:\/\///;  
                       $currenturl=~s/^[^\/]+//;  
   
 # ---------------------------------------------------------------- Send headers  
   
                           $r->content_type('text/html');  
                           $r->send_http_header;  
                           $r->print(  
                    '<html><head><title>Navigate LON-CAPA Maps</title></head>');  
   
   $r->print('<body bgcolor="#FFFFFF"');  
                           if (($currenturl=~/^\/res/) &&  
                               ($currenturl!~/^\/res\/adm/)) {  
                              $r->print(' onLoad="window.location.hash='.  
        "'curloc'".'"');  
   }  
                           $r->print('><script>window.focus();</script>'.  
                            '<img align=right src=/adm/lonIcons/lonlogos.gif>'.  
                                     '<h1>Navigate Course Map</h1>');  
       $r->rflush();  
                       if (($currenturl=~/^\/res/) &&  
                           ($currenturl!~/^\/res\/adm/)) {  
        $r->print('<a href="#curloc">Current Location</a><p>');  
                       }  
 # ----------------------------------------------------- The little content list  
                       for ($i=0;$i<=$#rows;$i++) {  
  if ($rows[$i]) {  
                           my @colcont=split(/\&/,$rows[$i]);  
                           my $avespan=$lcm/($#colcont+1);  
                           for ($j=0;$j<=$#colcont;$j++) {  
                               my $rid=$colcont[$j];  
                               if ($rid=~/^h(.+)/) {  
   $rid=$1;  
                                   $r->print(  
      '&nbsp;&nbsp;&nbsp;<a href="#'.$rid.'">'.$hash{'title_'.$rid}.'</a><br>');  
                               }  
                           }  
         }  
                       }  
 # ----------------------------------------------------------------- Start table  
                       $r->print('<hr><table cols="'.$lcm.'" border="0">');  
                       for ($i=0;$i<=$#rows;$i++) {  
  if ($rows[$i]) {  
                           $r->print("\n<tr>");  
                           my @colcont=split(/\&/,$rows[$i]);  
                           my $avespan=$lcm/($#colcont+1);  
                           for ($j=0;$j<=$#colcont;$j++) {  
                               my $rid=$colcont[$j];  
                               my $add='<td>&nbsp;&nbsp;';  
                               my $adde='</td>';  
                               my $hwk='<font color="#223322">';  
                               my $hwke='</font>';  
                               if ($rid=~/^h(.+)/) {  
   $rid=$1;  
                                   $add=  
                                    '<th bgcolor="#AAFF55"><a name="'.$rid.'">';  
                                   $adde='</th>';  
                               }  
                             if ($rid=~/^p(\d)(\d)\"([\w\: \(\)\/\,]*)\"(.+)/) {  
                                   my $code=$1;  
                                   my $tcode=$2;  
                                   my $ctext=$3;  
                                   $rid=$4;  
                                   if ($tcode eq '1') {  
                                      $add='<td bgcolor="#AAAAAA">';  
                                   }  
                                   if ($code eq '3') {  
                                      $add='<td bgcolor="#AAFFAA">';  
   } else {  
                                       $add='<td bgcolor="#FFAAAA">';  
       if ($tcode eq '2') {  
                                          $add='<td bgcolor="#FFFFAA">';  
                                       }  
                                       if ($tcode eq '4') {  
                                          $add='<td bgcolor="#FFFF33"><blink>';  
                                          $adde='</blink></td>';  
                                       }  
                                   }  
                                   $hwk='<font color="#888811"><b>';  
                                   $hwke='</b></font>';  
                                   if ($code eq '1') {  
                                      $hwke='</b> ('.$ctext.')</font>';  
                                   }  
                                   if ($code eq '2') {  
                                      $hwk='<font color="#992222"><b>';  
                                      $hwke='</b> ('.$ctext.')</font>';  
                                   }  
                                   if ($code eq '3') {  
                                      $hwk='<font color="#229922"><b>';  
                                      $hwke='</b> ('.$ctext.')</font>';  
                                   }  
                               }  
       if ($hash{'src_'.$rid} eq $currenturl) {  
                                   $add=$add.'<a name="curloc"></a>'.  
       '<font color=red><b>-&gt; </b></font>';  
                                   $adde=  
                                 '<font color=red><b> &lt;-</b></font>'.$adde;  
                               }  
                               $r->print($add.'<a href="'.$hash{'src_'.$rid}.  
                                 '">'.$hwk.  
                                 $hash{'title_'.$rid}.$hwke.'</a>'.$adde);  
                           }  
                           $r->print('</tr>');  
         }  
                       }  
                       $r->print("\n</table>");  
                       $r->print('</body></html>');  
 # -------------------------------------------------------------------- End page  
                   }                    
 # ------------------------------------------------------------- End render page  
               } else {  
                   $r->content_type('text/html');  
                   $r->send_http_header;  
   $r->print('<html><body>Coursemap undefined.</body></html>');  
               }  
 # ------------------------------------------------------------------ Untie hash  
               unless (untie(%hash)) {  
                    &Apache::lonnet::logthis("<font color=blue>WARNING: ".  
                        "Could not untie coursemap $fn (browse).</font>");   
               }  
               unless (untie(%parmhash)) {  
                    &Apache::lonnet::logthis("<font color=blue>WARNING: ".  
                        "Could not untie parmhash (browse).</font>");   
               }  
 # -------------------------------------------------------------------- All done  
       return OK;  
 # ----------------------------------------------- Errors, hash could no be tied  
           }  
       }   
   }  
   
   $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";  Maps can contain empty resources. The iterator will automatically skip
   return HTTP_NOT_ACCEPTABLE;   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.
   
   =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.
   
   =back
   
   =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 = {};
   
       $self->{NAV_MAP} = shift;
       return undef unless ($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 && $resource->is_map() && !$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}, 0);
           
       }
   
       # 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;
   
       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();
   
           # 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 ($self->{HERE}->is_map() &&
           (defined($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();
   
           $self->{RECURSIVE_ITERATOR} = 
               Apache::lonnavmaps::iterator->new($self->{NAV_MAP}, $firstResource,
                                                 $finishResource, $self->{FILTER},
                                                 $self->{ALREADY_SEEN}, $self->{CONDITION});
       }
   
       # 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();
       }
   
       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;  1;
 __END__  
   
   package Apache::lonnavmaps::DFSiterator;
   
   # 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 seperate, 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 = {};
   
       $self->{NAV_MAP} = shift;
       return undef unless ($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 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 = {};
   
       $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 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 $self->{NAV_MAP}->{PARM_HASH}->{$self->symb .
                                                  '.0.parameter_randompick'};
   }
   sub src { 
       my $self=shift;
       return $self->navHash("src_", 1);
   }
   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 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 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 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_problem {
       my $self=shift;
       my $src = $self->src();
       return ($src =~ /problem$/);
   }
   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';
   }
   
   # 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) = @_;
       return $self->parmval("duedate", $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 $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'});
   
   }
   
   # 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<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 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<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 multipart {
       my $self = shift;
       return $self->countParts() > 1;
   }
   
   sub responseType {
       my $self = shift;
       my $part = shift;
   
       $self->extractParts();
       return $self->{RESPONSE_TYPES}->{$part};
   }
   
   sub responseIds {
       my $self = shift;
       my $part = shift;
   
       $self->extractParts();
       return $self->{RESPONSE_IDS}->{$part};
   }
   
   # 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 $metadata = &Apache::lonnet::metadata($self->src(), 'packages');
           if (!$metadata) {
               $self->{RESOURCE_ERROR} = 1;
               $self->{PARTS} = [];
               $self->{PART_TYPE} = {};
               return;
           }
           foreach (split(/\,/,$metadata)) {
               if ($_ =~ /^part_(.*)$/) {
                   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;
   
           my %responseIdHash;
           my %responseTypeHash;
   
   
           # Init the responseIdHash
           foreach (@{$self->{PARTS}}) {
               $responseIdHash{$_} = [];
           }
   
           # Now, the unfortunate thing about this is that parts, part name, and
           # response if 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_(.*)/) {
                   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;
                           $responseTypeHash{$partIdSoFar} = $responseType;
                           last;
                       }
                   }
               }
           }
   
           $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;
       return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE});
   
       my $status = $self->queryRestoreHash('solved', shift);
   
       # Left as seperate if statements in case we ever do more with this
       if ($status eq 'correct_by_student') {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 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 $suppressFeedback = lc($self->parmval("problemstatus", $part)) eq 'no';
   
       # There are a few whole rows we can dispose of:
       if ($completionStatus == CORRECT ||
           $completionStatus == CORRECT_BY_OVERRIDE ) {
           return $suppressFeedback? ANSWER_SUBMITTED : CORRECT; 
       }
   
       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 $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,
         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<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);
           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());
   }
   
   =pod
   
   =back
   
   =cut
   
   1;
   
   __END__
   
   
Removed from v.1.15  
changed lines
  Added in v.1.224

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