--- loncom/interface/lonstatistics.pm	2002/08/13 00:37:18	1.41
+++ loncom/interface/lonstatistics.pm	2005/03/01 22:25:59	1.118
@@ -1,7 +1,6 @@
 # The LearningOnline Network with CAPA
-# (Publication Handler
 #
-# $Id: lonstatistics.pm,v 1.41 2002/08/13 00:37:18 stredwic Exp $
+# $Id: lonstatistics.pm,v 1.118 2005/03/01 22:25:59 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -26,607 +25,1017 @@
 # http://www.lon-capa.org/
 #
 # (Navigate problems for statistical reports
-# YEAR=2001
-# 5/5,7/9,7/25/1,8/11,9/13,9/26,10/5,10/9,10/22,10/26 Behrouz Minaei
-# 11/1,11/4,11/16,12/14,12/16,12/18,12/20,12/31 Behrouz Minaei
-# YEAR=2002
-# 1/22,2/1,2/6,2/25,3/2,3/6,3/17,3/21,3/22,3/26,4/7,5/6 Behrouz Minaei
-# 5/12,5/14,5/15,5/19,5/26,7/16,25/7,29/7  Behrouz Minaei
 #
 ###
 
-package Apache::lonstatistics; 
+=pod
+
+=head1 NAME
+
+lonstatistics
+
+=head1 SYNOPSIS
+
+Main handler for statistics and chart.
+
+=over 4
+
+=cut
+
+package Apache::lonstatistics;
 
 use strict;
 use Apache::Constants qw(:common :http);
+use vars qw(
+    @FullClasslist 
+    @Students
+    @Sections 
+    @SelectedSections
+    %StudentData
+    @StudentDataOrder
+    @SelectedStudentData
+    $enrollment_status);
+
 use Apache::lonnet();
 use Apache::lonhomework;
 use Apache::loncommon;
 use Apache::loncoursedata;
 use Apache::lonhtmlcommon;
-use Apache::lonproblemanalysis;
-use Apache::lonproblemstatistics;
-use Apache::lonstudentassessment;
-use HTML::TokeParser;
-use GDBM_File;
+use Apache::lonmysql;
+use Apache::lonlocal;
+use Time::HiRes;
+#
+# Statistics Packages
+use Apache::lonproblemanalysis();
+use Apache::lonsubmissiontimeanalysis();
+use Apache::loncorrectproblemplot();
+use Apache::lonproblemstatistics();
+use Apache::lonstudentassessment();
+use Apache::lonpercentage;
+use Apache::lonstudentsubmissions();
+use Apache::lonsurveyreports();
 
+#######################################################
+#######################################################
 
-sub CheckFormElement {
-    my ($cache, $ENVName, $cacheName, $default)=@_;
-
-    if(defined($ENV{'form.'.$ENVName})) {
-        $cache->{$cacheName} = $ENV{'form.'.$ENVName};
-    } elsif(!defined($cache->{$cacheName})) {
-        $cache->{$cacheName} = $default;
-    }
+=pod
 
-    return;
-}
+=item Package Variables
 
-sub ProcessFormData{
-    my ($cache)=@_;
+=item @FullClasslist The full classlist
 
-    $cache->{'reportKey'} = 'false';
+=item @Students The students we are concerned with for this invocation
 
-    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
-                                            ['sort','download',
-                                             'reportSelected',
-                                             'StudentAssessmentStudent',
-                                             'ProblemStatisticsSort']);
-    &CheckFormElement($cache, 'Status', 'Status', 'Active');
-    &CheckFormElement($cache, 'postdata', 'reportSelected', 'Class list');
-    &CheckFormElement($cache, 'reportSelected', 'reportSelected', 
-                      'Class list');
-    $cache->{'reportSelected'} = 
-        &Apache::lonnet::unescape($cache->{'reportSelected'});
-    &CheckFormElement($cache, 'DownloadAll', 'DownloadAll', 'false');
-    &CheckFormElement($cache, 'sort', 'sort', 'fullname');
-    &CheckFormElement($cache, 'download', 'download', 'false');
-
-    # student assessment
-    if(defined($ENV{'form.CreateStudentAssessment'}) ||
-       defined($ENV{'form.NextStudent'}) ||
-       defined($ENV{'form.PreviousStudent'})) {
-        $cache->{'reportSelected'} = 'Student Assessment';
-    }
-    if(defined($ENV{'form.NextStudent'})) {
-        $cache->{'StudentAssessmentMove'} = 'next';
-    } elsif(defined($ENV{'form.PreviousStudent'})) {
-        $cache->{'StudentAssessmentMove'} = 'previous';
-    } else {
-        $cache->{'StudentAssessmentMove'} = 'selected';
-    }
-    &CheckFormElement($cache, 'StudentAssessmentStudent', 
-                      'StudentAssessmentStudent', 'All Students');
-    $cache->{'StudentAssessmentStudent'} = 
-        &Apache::lonnet::unescape($cache->{'StudentAssessmentStudent'});
-    &CheckFormElement($cache, 'DefaultColumns', 'DefaultColumns', 'false');
-
-    if(defined($ENV{'form.Section'})) {
-        my @sectionsSelected = (ref($ENV{'form.Section'}) ?
-                               @{$ENV{'form.Section'}} :
-                                ($ENV{'form.Section'}));
-        $cache->{'sectionsSelected'} = join(':', @sectionsSelected);
-    } elsif(!defined($cache->{'sectionsSelected'})) {
-        $cache->{'sectionsSelected'} = $cache->{'sectionList'};
-    }
-
-    # Problem analysis
-    &CheckFormElement($cache, 'Interval', 'Interval', '1');
-
-    # ProblemStatistcs
-    &CheckFormElement($cache, 'DisplayCSVFormat',
-                      'DisplayFormat', 'Display Table Format');
-    &CheckFormElement($cache, 'ProblemStatisticsAscend',
-                      'ProblemStatisticsAscend', 'Ascending');
-    &CheckFormElement($cache, 'ProblemStatisticsMaps', 
-                      'ProblemStatisticsMaps', 'All Maps');
-    &CheckFormElement($cache, 'ProblemStatisticsSort',
-                      'ProblemStatisticsSort', 'Homework Sets Order');
-
-    # Search only form elements
-    my @headingColumns=();
-    my @sequenceColumns=();
-    my $foundColumn = 0;
-    if(defined($ENV{'form.ReselectColumns'})) {
-        my @reselected = (ref($ENV{'form.ReselectColumns'}) ? 
-                          @{$ENV{'form.ReselectColumns'}}
-                          : ($ENV{'form.ReselectColumns'}));
-        foreach (@reselected) {
-            if(/HeadingColumn/) {
-                push(@headingColumns, $_);
-                $foundColumn = 1;
-            } elsif(/SequenceColumn/) {
-                push(@sequenceColumns, $_);
-                $foundColumn = 1;
-            }
-        }
-    }
-
-    $cache->{'reportKey'} = 'false';
-    if($cache->{'reportSelected'} eq 'Analyze') {
-        $cache->{'reportKey'} = 'Analyze';
-    } elsif($cache->{'reportSelected'} eq 'DoDiffGraph') {
-        $cache->{'reportKey'} = 'DoDiffGraph';
-    } elsif($cache->{'reportSelected'} eq 'PercentWrongGraph') {
-        $cache->{'reportKey'} = 'PercentWrongGraph';
-    }
-
-    if(defined($ENV{'form.DoDiffGraph'})) {
-        $cache->{'reportSelected'} = 'DoDiffGraph';
-        $cache->{'reportKey'} = 'DoDiffGraph';
-    } elsif(defined($ENV{'form.PercentWrongGraph'})) {
-        $cache->{'reportSelected'} = 'PercentWrongGraph';
-        $cache->{'reportKey'} = 'PercentWrongGraph';
-    }
-
-    foreach (keys(%ENV)) {
-        if(/form\.Analyze/) {
-            $cache->{'reportSelected'} = 'Analyze';
-            $cache->{'reportKey'} = 'Analyze';
-            my $data;
-            (undef, $data)=split(':::', $_);
-            $cache->{'AnalyzeInfo'}=$data;
-        } elsif(/form\.HeadingColumn/) {
-            my $value = $_;
-            $value =~ s/form\.//;
-            push(@headingColumns, $value);
-            $foundColumn=1;
-        } elsif(/form\.SequenceColumn/) {
-            my $value = $_;
-            $value =~ s/form\.//;
-            push(@sequenceColumns, $value);
-            $foundColumn=1;
-        }
-    }
-
-    if($foundColumn) {
-        $cache->{'HeadingsFound'} = join(':', @headingColumns);
-        $cache->{'SequencesFound'} = join(':', @sequenceColumns);;
-    }
-    if(!defined($cache->{'HeadingsFound'}) || 
-       $cache->{'DefaultColumns'} ne 'false') {
-        $cache->{'HeadingsFound'}='HeadingColumnFull Name';
-    }
-    if(!defined($cache->{'SequencesFound'}) ||
-       $cache->{'DefaultColumns'} ne 'false') {
-        $cache->{'SequencesFound'}='All Sequences';
-    }
-    $cache->{'DefaultColumns'} = 'false';
+=item @Sections The sections available in this class
 
-    return;
-}
+=item $curr_student The student currently being examined
+
+=item $prev_student The student previous in the classlist
+
+=item $next_student The student next in the classlist
+
+=over
+
+=cut 
+
+#######################################################
+#######################################################
+#
+# Classlist variables
+#
+my $curr_student;
+my $prev_student;
+my $next_student;
+
+#######################################################
+#######################################################
 
 =pod
 
-=item &SortStudents()
+=item &clear_classlist_variables()
 
-Determines which students to display and in which order.  Which are 
-displayed are determined by their status(active/expired).  The order
-is determined by the sort button pressed (default to username).  The
-type of sorting is username, lastname, or section.
+undef the following package variables:
 
-=over 4
+=over
+
+=item @FullClasslist
+
+=item @Students
+
+=item @Sections
 
-Input: $students, $CacheData
+=item @SelectedSections
 
-$students: A array pointer to a list of students (username:domain)
+=item %StudentData
 
-$CacheData: A pointer to the hash tied to the cached data
+=item @StudentDataOrder
 
-Output: \@order
+=item @SelectedStudentData
 
-@order: An ordered list of students (username:domain)
+=item $curr_student
+
+=item $prev_student
+
+=item $next_student
 
 =back
 
 =cut
 
-sub SortStudents {
-    my ($cache)=@_;
+#######################################################
+#######################################################
+sub clear_classlist_variables {
+    undef(@FullClasslist);
+    undef(@Students);
+    undef(@Sections);
+    undef(@SelectedSections);
+    undef(%StudentData);
+    undef(@SelectedStudentData);
+    undef($curr_student);
+    undef($prev_student);
+    undef($next_student);
+}
+
+#######################################################
+#######################################################
+
+=pod
+
+=item &PrepareClasslist()
+
+Build up the classlist information.  The classlist information is kept in
+the following package variables:
+
+=over
+
+=item @FullClasslist
+
+=item @Students
 
-    my @students = split(':::',$cache->{'NamesOfStudents'});
-    my @sorted1Students=();
-    foreach (@students) {
-        if($cache->{'Status'} eq 'Any' || 
-           $cache->{$_.':Status'} eq $cache->{'Status'}) {
-            push(@sorted1Students, $_);
+=item @Sections
+
+=item @SelectedSections
+
+=item %StudentData
+
+=item @SelectedStudentData
+
+=item $curr_student
+
+=item $prev_student
+
+=item $next_student
+
+=back
+
+$curr_student, $prev_student, and $next_student may not be defined, depending
+upon the calling context.
+
+=cut
+
+#######################################################
+#######################################################
+sub PrepareClasslist {
+    my %Sections;
+    &clear_classlist_variables();
+    #
+    # Retrieve the classlist
+    my $cid  = $ENV{'request.course.id'};
+    my $cdom = $ENV{'course.'.$cid.'.domain'};
+    my $cnum = $ENV{'course.'.$cid.'.num'};
+    my ($classlist,$field_names) = &Apache::loncoursedata::get_classlist($cid,
+                                                                  $cdom,$cnum);
+    if (exists($ENV{'form.Section'})) {
+        if (ref($ENV{'form.Section'})) {
+            @SelectedSections = @{$ENV{'form.Section'}};
+        } elsif ($ENV{'form.Section'} !~ /^\s*$/) {
+            @SelectedSections = ($ENV{'form.Section'});
+        }
+    }
+    @SelectedSections = ('all') if (! @SelectedSections);
+    foreach (@SelectedSections) {
+        if ($_ eq 'all') {
+            @SelectedSections = ('all');
+        }
+    }
+    #
+    # Deal with instructors with restricted section access
+    if ($ENV{'request.course.sec'} !~ /^\s*$/) {
+        @SelectedSections = ($ENV{'request.course.sec'});
+    }
+    #
+    # Set up %StudentData
+    @StudentDataOrder = qw/fullname username domain id section status comments/;
+    foreach my $field (@StudentDataOrder) {
+        $StudentData{$field}->{'title'} = &mt($field);
+        $StudentData{$field}->{'base_width'} = length(&mt($field));
+        $StudentData{$field}->{'width'} = 
+                               $StudentData{$field}->{'base_width'};
+    }
+    #
+    # get the status requested
+    $enrollment_status = 'Active';
+    $enrollment_status = $ENV{'form.Status'} if (exists($ENV{'form.Status'}));
+    #
+    # Process the classlist
+    while (my ($student,$student_data) = each (%$classlist)) {
+        my $studenthash = ();
+        for (my $i=0; $i< scalar(@$field_names);$i++) {
+            my $field = $field_names->[$i];
+            # Store the data
+            $studenthash->{$field}=$student_data->[$i];
+            # Keep track of the width of the fields
+            next if (! exists($StudentData{$field}));
+            my $length = length($student_data->[$i]);
+            if ($StudentData{$field}->{'width'} < $length) {
+                $StudentData{$field}->{'width'} = $length; 
+            }
+        }
+        push (@FullClasslist,$studenthash);
+        #
+        # Build up a list of sections
+        my $section = $studenthash->{'section'};
+        if (! defined($section) || $section =~/^\s*$/ || $section == -1) {
+            $studenthash->{'section'} = 'none';
+            $section = $studenthash->{'section'};
+        }
+        $Sections{$section}++;
+        #
+        # Only put in the list those students we are interested in
+        foreach my $sect (@SelectedSections) {
+            if ( (($sect eq 'all') || 
+                  ($section eq $sect)) &&
+                 (($studenthash->{'status'} eq $enrollment_status) || 
+                  ($enrollment_status eq 'Any')) 
+                 ){
+                push (@Students,$studenthash);
+                last;
+            }
+        }
+    }
+    #
+    # Put the consolidated section data in the right place
+    if ($ENV{'request.course.sec'} !~ /^\s*$/) {
+        @Sections = ($ENV{'request.course.sec'});
+    } else {
+        @Sections = sort {$a cmp $b} keys(%Sections);
+        unshift(@Sections,'all'); # Put 'all' at the front of the list
+    }
+    #
+    # Sort the Students
+    my $sortby = 'fullname';
+    $sortby = $ENV{'form.sort'} if (exists($ENV{'form.sort'}));
+    my @TmpStudents = sort { $a->{$sortby} cmp $b->{$sortby} ||
+                             $a->{'fullname'} cmp $b->{'fullname'} } @Students;
+    @Students = @TmpStudents;
+    # 
+    # Now deal with that current student thing....
+    $curr_student = undef;
+    if (exists($ENV{'form.SelectedStudent'})) {
+        my ($current_uname,$current_dom) = 
+            split(':',$ENV{'form.SelectedStudent'});
+        my $i;
+        for ($i = 0; $i<=$#Students; $i++) {
+            next if (($Students[$i]->{'username'} ne $current_uname) || 
+                     ($Students[$i]->{'domain'}   ne $current_dom));
+            $curr_student = $Students[$i];
+            last; # If we get here, we have our student.
+        }
+        if (defined($curr_student)) {
+            if ($i == 0) {
+                $prev_student = undef;
+            } else {
+                $prev_student = $Students[$i-1];
+            }
+            if ($i == $#Students) {
+                $next_student = undef;
+            } else {
+                $next_student = $Students[$i+1];
+            }
+        }
+    }
+    #
+    if (exists($ENV{'form.StudentData'})) {
+        if (ref($ENV{'form.StudentData'}) eq 'ARRAY') {
+            @SelectedStudentData = @{$ENV{'form.StudentData'}};
+        } else {
+            @SelectedStudentData = ($ENV{'form.StudentData'});
+        }
+    } else {
+        @SelectedStudentData = ('username');
+    }
+    foreach (@SelectedStudentData) {
+        if ($_ eq 'all') {
+            @SelectedStudentData = ('all');
+            last;
         }
     }
+    #
+    return;
+}
+
+
+#######################################################
+#######################################################
+
+=pod
+
+=item get_students
+
+Returns a list of the selected students
+
+=cut
 
-    my $sortBy = '';
-    if(defined($cache->{'sort'})) {
-        $sortBy = ':'.$cache->{'sort'};
+#######################################################
+#######################################################
+sub get_students {
+    if (! @Students) {
+        &PrepareClasslist()
     }
-    my @order = sort { $cache->{$a.$sortBy} cmp $cache->{$b.$sortBy} ||
-                       $cache->{$a.':fullname'} cmp $cache->{$b.':fullname'} } 
-                @sorted1Students;
+    return @Students;
+}
+
+#######################################################
+#######################################################
+
+=pod
+
+=item &current_student()
+
+Returns a pointer to a hash containing data about the currently
+selected student.
+
+=cut
 
-    return \@order;
+#######################################################
+#######################################################
+sub current_student { 
+    return $curr_student;
 }
 
+#######################################################
+#######################################################
+
 =pod
 
-=item &SpaceColumns()
+=item &previous_student()
 
-Determines the width of all the columns in the chart.  It is based on
-the max of the data for that column and its header.
+Returns a pointer to a hash containing data about the student prior
+in the list of students.  Or something.  
 
-=over 4
+=cut
+
+#######################################################
+#######################################################
+sub previous_student { 
+    return $prev_student;
+}
+
+#######################################################
+#######################################################
+
+=pod
+
+=item &next_student()
+
+Returns a pointer to a hash containing data about the next student
+to be viewed.
+
+=cut
+
+#######################################################
+#######################################################
+sub next_student { 
+    return $next_student;
+}
 
-Input: $students, $studentInformation, $headings, $ChartDB
+##############################################
+##############################################
 
-$students: An array pointer to a list of students (username:domain)
+=pod 
 
-$studentInformatin: The type of data for the student information.  It is
-used as part of the key in $CacheData.
+=item &StudentDataSelect($elementname,$status,$numvisible,$selected)
 
-$headings: The name of the student information columns.
+Returns html for a selection box allowing the user to choose one (or more) 
+of the fields of student data available (fullname, username, id, section, etc)
 
-$ChartDB: The name of the cache database which is opened for read/write.
+=over 4
 
-Output: None - All data stored in cache.
+=item $elementname The name of the HTML form element
+
+=item $status 'multiple' or 'single' selection box
+
+=item $numvisible The number of options to be visible
 
 =back
 
 =cut
 
-sub SpaceColumns {
-    my ($students,$studentInformation,$headings,$cache)=@_;
-
-    # Initialize Lengths
-    for(my $index=0; $index<(scalar @$headings); $index++) {
-        my @titleLength=split(//,$headings->[$index]);
-        $cache->{$studentInformation->[$index].':columnWidth'}=
-            scalar @titleLength;
-    }
-
-    foreach my $name (@$students) {
-        foreach (@$studentInformation) {
-            my @dataLength=split(//,$cache->{$name.':'.$_});
-            my $length=(scalar @dataLength);
-            if($length > $cache->{$_.':columnWidth'}) {
-                $cache->{$_.':columnWidth'}=$length;
+##############################################
+##############################################
+sub StudentDataSelect {
+    my ($elementname,$status,$numvisible)=@_;
+    if ($numvisible < 1) {
+        return;
+    }
+    #
+    # Build the form element
+    my $Str = "\n";
+    $Str .= '<select name="'.$elementname.'" ';
+    if ($status ne 'single') {
+        $Str .= 'multiple="true" ';
+    }
+    $Str .= 'size="'.$numvisible.'" >'."\n";
+    #
+    # Deal with 'all'
+    $Str .= '    <option value="all" ';
+    foreach (@SelectedStudentData) {
+        if ($_ eq 'all') {
+            $Str .= 'selected ';
+            last;
+        }
+    }
+    $Str .= ">all</option>\n";
+    #
+    # Loop through the student data fields
+    foreach my $item (@StudentDataOrder) {
+        $Str .= '    <option value="'.$item.'" ';
+        foreach (@SelectedStudentData) {
+            if ($item eq $_ ) {
+                $Str .= 'selected ';
+                last;
             }
         }
+        $Str .= '>'.$item."</option>\n";
     }
-
-    return;
+    $Str .= "</select>\n";
+    return $Str;
 }
 
-sub PrepareData {
-    my ($c, $cacheDB, $studentInformation, $headings,$r)=@_;
+#######################################################
+#######################################################
 
-    # Test for access to the cache data
-    my $courseID=$ENV{'request.course.id'};
-    my $isRecalculate=0;
-    if(defined($ENV{'form.Recalculate'})) {
-        $isRecalculate=1;
-    }
+=pod
 
-    my $isCached = &Apache::loncoursedata::TestCacheData($cacheDB, 
-                                                         $isRecalculate);
-    if($isCached < 0) {
-        return "Unable to tie hash to db file.";
-    }
+=item &get_selected_maps($elementname)
 
-    # Download class list information if not using cached data
-    my %cache;
-    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT(),0640)) {
-        return "Unable to tie hash to db file.";
-    }
+Input: Name of the <select> form element used to specify the maps.
+
+Returns: Array of symbs of selected maps or the description 'all'.
+   If form.$elementname does not exist, 'all' is returned.
+
+=cut
 
-    if(!$isCached) {
-        my $processTopResourceMapReturn=
-            &Apache::loncoursedata::ProcessTopResourceMap(\%cache, $c, $r);
-        if($processTopResourceMapReturn ne 'OK') {
-            untie(%cache);
-            return $processTopResourceMapReturn;
+#######################################################
+#######################################################
+sub get_selected_maps {
+    my ($elementname) = @_;
+    my @selected_maps;
+    if (exists($ENV{'form.'.$elementname})) {
+        if (ref($ENV{'form.'.$elementname})) {
+            @selected_maps = @{$ENV{'form.'.$elementname}};
+        } else {
+            @selected_maps = ($ENV{'form.'.$elementname});
         }
+    } else {
+        @selected_maps = ('all');
     }
-
-    if($c->aborted()) {
-        untie(%cache);
-        return 'aborted'; 
+    foreach my $map (@selected_maps) {
+        if ($map eq 'all') {
+            @selected_maps = ('all');
+            last;
+        }
     }
+    return @selected_maps;
+}
+
+
+#######################################################
+#######################################################
 
-    my $classlist=&Apache::loncoursedata::DownloadClasslist($courseID,
-                                                $cache{'ClasslistTimestamp'},
-                                                $c);
-    foreach (keys(%$classlist)) {
-        if(/^(con_lost|error|no_such_host)/i) {
-            untie(%cache);
-            return "Error getting student data.";
+=pod
+
+=item &selected_sequences_with_assessments
+
+Retrieve the sequences which were selected by the user to show.  
+
+Input: $mode: scalar.  Either 'selected' or 'all'.  If not specified,
+    'selected' is used.
+
+Returns: an array containing a navmap object and navmap resources, 
+    or an array containing a scalar with an error message.
+
+=cut
+
+#######################################################
+#######################################################
+sub selected_sequences_with_assessments {
+    my ($mode) = @_;
+    $mode = 'selected' if (! defined($mode));
+    my $navmap = Apache::lonnavmaps::navmap->new();
+    if (!defined($navmap)) {
+        return ('Can not open Coursemap');
+    }
+    #
+    my @sequences = $navmap->retrieveResources(undef,
+                                               sub { shift->is_map(); },1,0,1);
+    my @sequences_with_assessments;
+    for my $sequence ($navmap->getById('0.0'), @sequences) {
+	if ($navmap->hasResource($sequence,sub { shift->is_problem(); }, 0)){
+            push(@sequences_with_assessments,$sequence);
         }
     }
+    #
+    my @sequences_to_show;
+    foreach my $sequence (@sequences_with_assessments) {
+        if ($mode eq 'all') {
+            push (@sequences_to_show,$sequence);
+        } elsif ($mode eq 'selected') {
+            foreach my $map_symb (&get_selected_maps('Maps')) {
+                if ($sequence->symb eq $map_symb || $map_symb eq 'all'){
+                    push (@sequences_to_show,$sequence);
+                    last; # Only put it in once
+                }
+            }
+        }
 
-    if($c->aborted()) {
-        untie(%cache);
-        return 'aborted'; 
     }
+    return $navmap,@sequences_to_show;
+}
 
-    # Active is a temporary solution, remember to change
-    Apache::loncoursedata::ProcessClasslist(\%cache,$classlist,$courseID,$c);
-    if($c->aborted()) {
-        untie(%cache);
-        return 'aborted'; 
-    }
+##############################################
+##############################################
 
-    &ProcessFormData(\%cache);
-    my $students = &SortStudents(\%cache);
-    &SpaceColumns($students, $studentInformation, $headings, \%cache);
-    $cache{'updateTime:columnWidth'}=24;
+=pod 
 
-    if($cache{'download'} ne 'false') {
-        my @who = ($cache{'download'});
-        $cache{'download'} = 'false';
-        if(&Apache::loncoursedata::DownloadStudentCourseData(\@who, 'false', 
-                                                             $cacheDB, 'true', 
-                                                             'false', $courseID,
-                                                             $r, $c) ne 'OK') {
-            untie(%cache);
-            return 'Stop at download individual';
-        }
-    } elsif($cache{'DownloadAll'} ne 'false') {
-        $cache{'DownloadAll'} = 'false';
-        my @allStudents;
-        if($cache{'DownloadAll'} eq 'sorted') {
-            @allStudents = @$students;
-        } else {
-            @allStudents = split(':::', $cache{'NamesOfStudents'});
-        }
-        if(&Apache::loncoursedata::DownloadStudentCourseData(\@allStudents, 
-                                                             'false', 
-                                                             $cacheDB, 'true', 
-                                                             'true', $courseID,
-                                                             $r, $c) ne 'OK') {
-            untie(%cache);
-            return 'Stop at download all';
+=item &map_select($elementname,$status,$numvisible,$restriction) 
+
+Returns html for a selection box allowing the user to choose one (or more) 
+of the sequences in the course.  The values of the sequences are the symbs.
+If the top sequence is selected, the value 'top' will result.
+
+=over 4
+
+=item $elementname The name of the HTML form element
+
+=item $status 'multiple' or 'single' selection box
+
+=item $numvisible The number of options to be visible
+
+=back
+
+=cut
+
+##############################################
+##############################################
+sub map_select {
+    my ($elementname,$status,$numvisible)=@_;
+    if ($numvisible < 1) {
+        return;
+    }
+    #
+    # Set up array of selected items
+    my @selected_maps = &get_selected_maps($elementname);
+    #
+    # Build the form element
+    my $form = "\n";
+    $form .= '<select name="'.$elementname.'" ';
+    if ($status ne 'single') {
+        $form .= 'multiple="true" ';
+    }
+    $form .= 'size="'.$numvisible.'" >'."\n";
+    #
+    # Put in option for 'all'
+    $form .= '    <option value="all" ';
+    if ($selected_maps[0] eq 'all') {
+        $form .= 'selected ';
+    }
+    $form .= ">all</option>\n";
+    #
+    # Loop through the sequences
+    my @sequences = &selected_sequences_with_assessments('all');
+    my $navmap;
+    if (!ref($sequences[0])) {
+        return $sequences[0];
+    } else {
+        $navmap = shift(@sequences);
+    }
+    foreach my $seq (@sequences){
+        $form .= '    <option value="'.$seq->symb.'" ';
+        foreach (@selected_maps) {
+            if ($seq->symb eq $_) {
+                $form .= 'selected ';
+                last;
+            }
         }
+        $form .= '>'.$seq->compTitle."</option>\n";
     }
+    $form .= "</select>\n";
+    return $form;
+}
 
-    if($c->aborted()) {
-        untie(%cache);
-        return 'aborted'; 
-    }
+##############################################
+##############################################
 
-    untie(%cache);
+=pod 
 
-    return ('OK', $students);
-}
+=item &SectionSelect($elementname,$status,$numvisible) 
+
+Returns html for a selection box allowing the user to choose one (or more) 
+of the sections in the course.  
+
+Uses the package variables @Sections and @SelectedSections
+=over 4
+
+=item $elementname The name of the HTML form element
+
+=item $status 'multiple' or 'single' selection box
+
+=item $numvisible The number of options to be visible
 
-sub BuildClasslist {
-    my ($cacheDB,$students,$studentInformation,$headings,$r)=@_;
+=back
+
+=cut
+
+##############################################
+##############################################
+sub SectionSelect {
+    my ($elementname,$status,$numvisible)=@_;
+    if ($numvisible < 1) {
+        return;
+    }
+    #
+    # Make sure we have the data we need to continue
+    if (! @Sections) {
+        &PrepareClasslist()
+    }
+    #
+    # Build the form element
+    my $Str = "\n";
+    $Str .= '<select name="'.$elementname.'" ';
+    if ($status ne 'single') {
+        $Str .= 'multiple="true" ';
+    }
+    $Str .= 'size="'.$numvisible.'" >'."\n";
+    #
+    # Loop through the sequences
+    foreach my $s (@Sections) {
+        $Str .= '    <option value="'.$s.'" ';
+        foreach (@SelectedSections) {
+            if ($s eq $_) {
+                $Str .= 'selected ';
+                last;
+            }
+        }
+        $Str .= '>'.$s."</option>\n";
+    }
+    $Str .= "</select>\n";
+    return $Str;
+}
 
-    my %cache;
-    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
-        return '<html><body>Unable to tie database.</body></html>';
+##################################################
+##################################################
+sub DisplayClasslist {
+    my ($r)=@_;
+    &Apache::lonhtmlcommon::add_breadcrumb
+        ({text=>'Select One Student'});
+    #
+    # Output some of the standard interface components
+    my $Str;
+    $Str .= &Apache::lonhtmlcommon::breadcrumbs(undef,'Select One Student');
+    $Str .= '<p><table cellspacing="5">'."\n";
+    $Str .= '<tr>';
+    $Str .= '<th align="center"><b>'.&mt('Sections').'</b></th>';
+    $Str .= '<th align="center"><b>'.&mt('Enrollment Status').'</b></th>';
+    $Str .= '</tr>'.$/;
+    $Str .= '<tr>';
+    $Str .= '<td>'.
+        &Apache::lonstatistics::SectionSelect('Section','multiple',5).
+        '</td>';
+    $Str .= '<td>'.
+        &Apache::lonhtmlcommon::StatusOptions(undef,undef,5).
+        '</td>';
+    
+    $Str .= '</tr>'.$/;
+    $Str .= '</table></p>';
+    $Str .= '<input type="submit" name="selectstudent" value="'.
+        &mt('Update Display').'" />';
+    $r->print($Str);
+    $r->rflush();
+    #
+    my @Fields = ('fullname','username','domain','id','section','status');
+    #
+    $Str = '';
+    if (! @Students) {
+        if ($SelectedSections[0] eq 'all') { 
+            if (lc($ENV{'form.Status'}) eq 'any') {
+                $Str .= '<h2>'.
+                    &mt('There are no students in the course.').
+                    '</h2>';
+            } elsif (lc($ENV{'form.Status'}) eq 'active') {
+                $Str .= '<h2>'.
+                &mt('There are no currently enrolled students in the course.').
+                    '</h2>';
+            } elsif (lc($ENV{'form.Status'}) eq 'expired') {
+                $Str .= '<h2>'.
+                    &mt('There are no previously enrolled students in the course.').
+                        '</h2>';
+            }
+        } else { 
+            my $sections;
+            if (lc($ENV{'form.Status'}) eq 'any') {
+                $Str .= '<h2>'.
+                    &mt('There are no students in the selected sections.').
+                    '</h2>';
+            } elsif (lc($ENV{'form.Status'}) eq 'active') {
+                $Str .= '<h2>'.
+                    &mt('There are no currently enrolled students in the selected sections.').
+                    '</h2>';
+            } elsif (lc($ENV{'form.Status'}) eq 'expired') {
+                $Str .= '<h2>'.
+                    &mt('There are no previously enrolled students in the selected sections.').
+                    '</h2>';
+            }
+        }
+        $Str.= '<a href="/adm/statistics?reportSelected=student_assessment">'.
+            &mt('Click here to return to the chart').'</a>';
+        $r->print($Str);
+        $r->rflush();
+        return;
     }
 
-    my $Str='';
+    # "Click" is asinine but it is probably not my place to change the world.
+    $Str .= '<h2>Click on a students name or username to view their chart</h2>';
     $Str .= '<table border="0"><tr><td bgcolor="#777777">'."\n";
     $Str .= '<table border="0" cellpadding="3"><tr bgcolor="#e6ffff">'."\n";
-
-    my $displayString = '<td align="left"><a href="/adm/statistics?';
-    $displayString .= 'sort=LINKDATA">DISPLAYDATA&nbsp</a></td>'."\n";
-    $Str .= &Apache::lonhtmlcommon::CreateHeadings(\%cache, 
-                                                   $studentInformation,
-                                                   $headings, $displayString);
+    foreach my $field (@Fields) {
+        $Str .= '<th><a href="/adm/statistics?'.
+            'reportSelected=student_assessment&'.
+            'selectstudent=1&'.
+            'sort='.$field.'">'.&mt($field).
+            '</a></th>';
+    }
     $Str .= '</tr>'."\n";
-
-    my $alternate=0;
-    foreach (@$students) {
-        my ($username, $domain) = split(':', $_);
+    #
+    my $alternate = 0;
+    foreach my $student (@Students) { # @Students is a package variable
+        my $sname = $student->{'username'}.':'.$student->{'domain'};
         if($alternate) {
             $Str .= '<tr bgcolor="#ffffe6">';
         } else {
             $Str .= '<tr bgcolor="#ffffc6">';
         }
         $alternate = ($alternate + 1) % 2;
-        foreach my $data (@$studentInformation) {
+        #
+        foreach my $field (@Fields) {
             $Str .= '<td>';
-            if($data eq 'fullname') {
+            if ($field eq 'fullname' || $field eq 'username') {
                 $Str .= '<a href="/adm/statistics?reportSelected=';
-                $Str .= &Apache::lonnet::escape('Student Assessment');
-                $Str .= '&StudentAssessmentStudent=';
-                $Str .= &Apache::lonnet::escape($cache{$_.':'.$data}).'">';
-                $Str .= $cache{$_.':'.$data}.'&nbsp';
+                $Str .= &Apache::lonnet::escape('student_assessment');
+                $Str .= '&sort='.&Apache::lonnet::escape($ENV{'form.sort'});
+                $Str .= '&SelectedStudent=';
+                $Str .= &Apache::lonnet::escape($sname).'">';
+                $Str .= $student->{$field}.'&nbsp';
                 $Str .= '</a>';
-            } elsif($data eq 'updateTime') {
-                $Str .= '<a href="/adm/statistics?reportSelected=';
-                $Str .= &Apache::lonnet::escape('Class list');
-                $Str .= '&download='.$_.'">';
-                $Str .= $cache{$_.':'.$data}.'&nbsp';
-                $Str .= '&nbsp</a>';
+            } elsif ($field eq 'status') {
+                $Str .= &mt($student->{$field});
             } else {
-                $Str .= $cache{$_.':'.$data}.'&nbsp';
+                $Str .= $student->{$field};
             }
-
-            $Str .= '</td>'."\n";
+            $Str .= '</td>';
         }
+        $Str .= "</tr>\n";
     }
-
-    $Str .= '</tr>'."\n";
     $Str .= '</table></td></tr></table>'."\n";
+    #
     $r->print($Str);
     $r->rflush();
-
-    untie(%cache);
-
+    #
     return;
 }
 
+##############################################
+##############################################
 sub CreateMainMenu {
-    my ($status, $reports)=@_;
-
-    my $Str = '';
-
-    $Str .= '<table border="0"><tbody><tr>'."\n";
-    $Str .= '<td></td><td></td>'."\n";
-    $Str .= '<td align="center"><b>Analysis Reports:</b></td>'."\n";
-    $Str .= '<td align="center"><b>Student Status:</b></td></tr>'."\n";
-    $Str .= '<tr>'."\n";
-    $Str .= '<td align="center"><input type="submit" name="Refresh" ';
-    $Str .= 'value="Refresh" /></td>'."\n";
-    $Str .= '<td align="center"><input type="submit" name="DownloadAll" ';
-    $Str .= 'value="Update All Student Data" /></td>'."\n";
-    $Str .= '<td align="center">';
-    $Str .= '<select name="reportSelected" onchange="document.';
-    $Str .= 'Statistics.submit()">'."\n";
-
-    foreach (sort(keys(%$reports))) {
-        next if($_ eq 'reportSelected');
-        $Str .= '<option name="'.$_.'"';
-        if($reports->{'reportSelected'} eq $reports->{$_}) {
-            $Str .= ' selected=""';
-        }
-        $Str .= '>'.$reports->{$_}.'</option>'."\n";
-    }
-    $Str .= '</select></td>'."\n";
-
-    $Str .= '<td align="center">';
-    $Str .= &Apache::lonhtmlcommon::StatusOptions($status, 'Statistics');
-    $Str .= '</td>'."\n";
-
-    $Str .= '</tr></tbody></table>'."\n";
-    $Str .= '<hr>'."\n";
-
+    #
+    # Define menu data
+    my @reports = ({ internal_name => 'problem_statistics',
+                     name => &mt('Overall Problem Statistics'),
+                     short_description => 
+    &mt('Student performance statistics on all problems.'),
+                 },
+                   { internal_name => 'problem_analysis',
+                     name => &mt('Detailed Problem Analysis'),
+                     short_description => 
+    &mt('Detailed statistics and graphs of student performance on problems.'),
+                 },
+                   { internal_name => 'submissiontime_analysis',
+                     name => &mt('Submission Time Plots'),
+                     short_description => 
+    &mt('Display and analysis of submission times on assessments.'),
+                 },
+                   { internal_name => 'student_submission_reports',
+                     name => &mt('Student Submission Reports'),
+                     short_description => 
+    &mt('Prepare reports of student submissions.'),
+                 },
+                   { internal_name => 'survey_reports',
+                     name => &mt('Survey Reports'),
+                     short_description => 
+    &mt('Prepare reports on survey results.'),
+                 },
+                   { internal_name => 'correct_problems_plot',
+                     name => &mt('Correct Problems Plot'),
+                     short_description => 
+    &mt('Display a histogram of student performance in the course.'),
+                 },
+#                   { internal_name => 'student_assessment',
+#                     name => &mt('Problem Status Chart'),
+#                     short_description => 
+#    &mt('Brief view of each students performance in course.'),
+#                 },
+                   # 'percentage'  => 'Correct-problems Plot',
+                   # 'activitylog' => 'Activity Log',
+                   );
+    #
+    # Create the menu
+    my $Str;
+    $Str .= '<h2>'.&mt('Please select a report to generate').'</h2>';
+    foreach my $reportdata (@reports) {
+        $Str .='    <h3><a href="/adm/statistics?reportSelected='.
+            $reportdata->{'internal_name'}.'" >'.
+            $reportdata->{'name'}."</a></h3>\n";
+        $Str .= '    '.('&nbsp;'x8).$reportdata->{'short_description'}.
+            "\n";
+    }
+    $Str .="</dl>\n";
+    #
     return $Str;
 }
 
-sub BuildStatistics {
-    my ($r)=@_;
-
-    my $c = $r->connection;
-    my @studentInformation=('fullname','section','id','domain','username',
-                            'updateTime');
-    my @headings=('Full Name', 'Section', 'PID', 'Domain', 'User Name',
-                  'Last Updated');
-    my $spacing = '   ';
-    my %reports = ('classlist'          => 'Class list',
-                   'problem_statistics' => 'Problem Statistics',
-                   'student_assessment' => 'Student Assessment',
-#                   'activitylog'        => 'Activity Log',
-                   'reportSelected'     => 'Class list');
-
-    my %cache;
-    my $courseID=$ENV{'request.course.id'};
-    my $cacheDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
-                  "_$ENV{'user.domain'}_$courseID\_statistics.db";
-
-    $r->print(&Apache::lonhtmlcommon::Title('LON-CAPA Statistics'));
-
-    my ($returnValue, $students) = &PrepareData($c, $cacheDB, 
-                                                \@studentInformation, 
-                                                \@headings,$r);
-    if($returnValue ne 'OK') {
-        $r->print($returnValue."\n".'</body></html>');
-        return OK;
-    }
-    if(!$c->aborted()) {
-        &Apache::loncoursedata::CheckForResidualDownload($cacheDB, 
-                                                         'true', 'true',
-                                                         $courseID,
-                                                         $r, $c);
-    }
-
-    my $GoToPage;
-    if(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
-        $GoToPage = $cache{'reportSelected'};
-        $reports{'reportSelected'} = $cache{'reportSelected'};
-        if(defined($cache{'reportKey'}) && 
-           !exists($reports{$cache{'reportKey'}}) && 
-           $cache{'reportKey'} ne 'false') {
-            $reports{$cache{'reportKey'}} = $cache{'reportSelected'};
+##############################################
+##############################################
+sub handler {
+    my $r=shift;
+    my $c = $r->connection();
+    #
+    # Check for overloading
+    my $loaderror=&Apache::lonnet::overloaderror($r);
+    if ($loaderror) { return $loaderror; }
+    $loaderror=
+       &Apache::lonnet::overloaderror($r,
+         $ENV{'course.'.$ENV{'request.course.id'}.'.home'});
+    if ($loaderror) { return $loaderror; }
+    #
+    # Check for access
+    if (! &Apache::lonnet::allowed('vgr',$ENV{'request.course.id'})) {
+        $ENV{'user.error.msg'}=
+            $r->uri.":vgr:0:0:Cannot view grades for complete course";
+        if (! &Apache::lonnet::allowed('vgr',
+                      $ENV{'request.course.id'}.'/'.$ENV{'request.course.sec'})) {
+            $ENV{'user.error.msg'}=
+                $r->uri.":vgr:0:0:Cannot view grades with given role";
+            return HTTP_NOT_ACCEPTABLE;
         }
-
-        if(defined($cache{'OptionResponses'})) {
-            $reports{'problem_analysis'} = 'Problem Analysis';
+    }
+    #
+    # Send the header
+    &Apache::loncommon::no_cache($r);
+    &Apache::loncommon::content_type($r,'text/html');
+    $r->send_http_header;
+    if ($r->header_only) { return OK; }
+    #
+    # Extract form elements from query string
+    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
+                                            ['sort','reportSelected',
+                                             'SelectedStudent']);
+    #
+    # Give the LON-CAPA page header
+    my $style = <<ENDSTYLE;
+<style type="text/css">
+    ul.sub_studentans { list-style-type: none }
+    ul.sub_correctans { list-style-type: none }
+    tr.even           { background-color: \#CCCCCC }
+    td.essay          { border: 1px solid gray; }
+</style>
+ENDSTYLE
+    my $html=&Apache::lonxml::xmlbegin();
+    $r->print($html.'<head><title>'.
+              &mt('Course Statistics and Charts').
+              '</title>'.$style.
+              "</head>\n".
+              &Apache::loncommon::bodytag('Course Statistics and Charts'));
+    $r->rflush();
+    # 
+    # Either print out a menu for them or send them to a report
+    &Apache::lonhtmlcommon::clear_breadcrumbs();
+    &Apache::lonhtmlcommon::add_breadcrumb({href=>'/adm/statistics',
+                                            title=>'Statistics',
+                                            text =>'Statistics',
+                                            faq=>139,
+                                            bug=>'Statistics and Charts'});
+    if (! exists($ENV{'form.reportSelected'}) || 
+        $ENV{'form.reportSelected'} eq '') {
+        $r->print(&Apache::lonhtmlcommon::breadcrumbs
+                  (undef,&mt('Statistics Main Page')).
+                  &CreateMainMenu());
+    } else {
+    #
+        if (! &Apache::lonmysql::verify_sql_connection()) {
+            my $serveradmin = $r->dir_config('lonAdmEMail');
+            $r->print('<h2><font color="Red">'.
+                      &mt('Unable to connect to database!').
+                      '</font></h2>');
+            $r->print('<p>'.
+                      &mt('Please notify the server administrator ').
+                      '<b>'.$serveradmin.'</b></p>');
+            $r->print('<p>'.
+                      &mt('Course Statistics and Charts cannot be '.
+                          'retrieved until the database is restarted.  '.
+                          'Your data is intact but cannot be displayed '.
+                          'at this time.').'</p>');
+            $r->print('</body></html>');
+            return;
         }
-
+        #
+        # Clean out the caches
+        if (exists($ENV{'form.ClearCache'})) {
+            &Apache::loncoursedata::delete_caches($ENV{'requres.course.id'});
+        }
+        #
+        # Begin form output
         $r->print('<form name="Statistics" ');
         $r->print('method="post" action="/adm/statistics">');
-        $r->print(&CreateMainMenu($cache{'Status'}, \%reports));
         $r->rflush();
-        untie(%cache);
-    } else {
-        $r->print('<html><body>Unable to tie database.</body></html>');
-        return OK;
-    }
-
-    if($GoToPage eq 'Activity Log') {
-        &Apache::lonproblemstatistics::Activity();
-    } elsif($GoToPage eq 'Problem Statistics') {
-        &Apache::lonproblemstatistics::BuildProblemStatisticsPage($cacheDB, 
-                                                                  $students, 
-                                                                  $courseID, 
-                                                                  $c,$r);
-    } elsif($GoToPage eq 'Problem Analysis') {
-        &Apache::lonproblemanalysis::BuildProblemAnalysisPage($cacheDB, $r);
-    } elsif($GoToPage eq 'Student Assessment') {
-        &Apache::lonstudentassessment::BuildStudentAssessmentPage($cacheDB,
-                                                          $students,
-                                                          $courseID,
-                                                          'Statistics',
-                                                          \@headings,
-                                                          $spacing,
-                                                          \@studentInformation,
-                                                          $r, $c);
-    } elsif($GoToPage eq 'Analyze') {
-        &Apache::lonproblemanalysis::BuildAnalyzePage($cacheDB, $students, 
-                                                      $courseID, $r);
-    } elsif($GoToPage eq 'DoDiffGraph' || $GoToPage eq 'PercentWrongGraph') {
-        &Apache::lonproblemstatistics::BuildGraphicChart($GoToPage,$r,$cacheDB);
-    } elsif($GoToPage eq 'Class list') {
-        &BuildClasslist($cacheDB, $students, \@studentInformation,
-                        \@headings, $r);
+        #
+        my $GoToPage = $ENV{'form.reportSelected'};
+        #
+        $r->print('<input type="hidden" name="reportSelected" value="'.
+                  $GoToPage.'">');
+        if($GoToPage eq 'activitylog') {
+#        &Apache::lonproblemstatistics::Activity();
+        } elsif($GoToPage eq 'problem_statistics') {
+            &Apache::lonhtmlcommon::add_breadcrumb
+                ({href=>'/adm/statistics?reportselected=problem_statistics',
+                  text=>'Overall Problem Statistics'});
+            &Apache::lonproblemstatistics::BuildProblemStatisticsPage($r,$c);
+        } elsif($GoToPage eq 'problem_analysis') {
+            &Apache::lonhtmlcommon::add_breadcrumb
+                ({href=>'/adm/statistics?reportselected=problem_analysis',
+                  text=>'Detailed Problem Analysis'});
+            &Apache::lonproblemanalysis::BuildProblemAnalysisPage($r,$c);
+        } elsif($GoToPage eq 'submissiontime_analysis') {
+            &Apache::lonhtmlcommon::add_breadcrumb
+                ({href=>
+                      '/adm/statistics?reportselected=submissiontime_analysis',
+                      text=>'Submission Time Plots'});
+            &Apache::lonsubmissiontimeanalysis::BuildSubmissionTimePage($r,$c);
+        } elsif($GoToPage eq 'student_submission_reports') {
+            &Apache::lonhtmlcommon::add_breadcrumb
+                ({href=>
+                  '/adm/statistics?reportselected=student_submission_reports',
+                  text=>'Student Submission Reports'});
+            &Apache::lonstudentsubmissions::BuildStudentSubmissionsPage($r,$c);
+        } elsif($GoToPage eq 'survey_reports') {
+            &Apache::lonhtmlcommon::add_breadcrumb
+                ({href=>
+                  '/adm/statistics?reportselected=survey_reports',
+                  text=>'Survey Reports'});
+            &Apache::lonsurveyreports::BuildSurveyReportsPage($r,$c);
+        } elsif($GoToPage eq 'correct_problems_plot') {
+            &Apache::lonhtmlcommon::add_breadcrumb
+                ({href=>'/adm/statistics?reportselected=correct_problems_plot',
+                  text=>'Correct Problems Plot'});
+            &Apache::loncorrectproblemplot::BuildCorrectProblemsPage($r,$c);
+        } elsif($GoToPage eq 'student_assessment') {
+            &Apache::lonhtmlcommon::clear_breadcrumbs();
+            &Apache::lonhtmlcommon::add_breadcrumb
+                ({href=>'/adm/statistics?reportselected=student_assessment',
+                  text=>'Chart'});
+            &Apache::lonstudentassessment::BuildStudentAssessmentPage($r,$c);
+        }
+        #
+        $r->print("</form>\n");
     }
-
-    $r->print('</form>'."\n");
-    $r->print("\n".'</body>'."\n".'</html>');
+    $r->print("</body>\n</html>\n");
     $r->rflush();
-
+    #
     return OK;
 }
 
-# ================================================================ Main Handler
-
-sub handler {
-    my $r=shift;
-
-#    $jr = $r;
+1;
 
-    unless(&Apache::lonnet::allowed('vgr',$ENV{'request.course.id'})) {
-        $ENV{'user.error.msg'}=
-        $r->uri.":vgr:0:0:Cannot view grades for complete course";
-        return HTTP_NOT_ACCEPTABLE; 
-    }
+#######################################################
+#######################################################
 
-    # Set document type for header only
-    if($r->header_only) {
-        if ($ENV{'browser.mathml'}) {
-            $r->content_type('text/xml');
-        } else {
-            $r->content_type('text/html');
-        }
-        &Apache::loncommon::no_cache($r);
-        $r->send_http_header;
-        return OK;
-    }
+=pod
 
-    unless($ENV{'request.course.fn'}) {
-	my $requrl=$r->uri;
-        $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
-        return HTTP_NOT_ACCEPTABLE; 
-    }
+=back
 
-    $r->content_type('text/html');
-    $r->send_http_header;
+=cut
 
-    &BuildStatistics($r);
+#######################################################
+#######################################################
 
-    return OK;
-}
-1;
 __END__