--- loncom/interface/lonstatistics.pm	2003/02/25 20:47:47	1.60
+++ loncom/interface/lonstatistics.pm	2010/05/03 16:41:51	1.152
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: lonstatistics.pm,v 1.60 2003/02/25 20:47:47 matthew Exp $
+# $Id: lonstatistics.pm,v 1.152 2010/05/03 16:41:51 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -28,199 +28,130 @@
 #
 ###
 
-=pod
-
-=head1 NAME
-
-lonstatistics
-
-=head1 SYNOPSIS
 
-Main handler for statistics and chart.
-
-=head1 PACKAGES USED
-
-    use strict;
-    use Apache::Constants qw(:common :http);
-    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 Apache::lonpercentage;
-    use GDBM_File;
-
-=over 4
-
-=cut
 
 package Apache::lonstatistics;
 
 use strict;
 use Apache::Constants qw(:common :http);
-use Apache::lonnet();
+use vars qw(
+    @FullClasslist 
+    @Students
+    @Sections
+    @Groups 
+    %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 Apache::lonmysql;
+use Apache::lonlocal;
+use Apache::longroup;
+use Time::HiRes;
+#
+# Statistics Packages
+use Apache::lonproblemanalysis();
+use Apache::lonsubmissiontimeanalysis();
+use Apache::loncorrectproblemplot();
+use Apache::lonproblemstatistics();
+use Apache::lonstudentassessment();
 use Apache::lonpercentage;
-use GDBM_File;
-
-use vars qw/@FullClasslist @Students @Sections @SelectedSections
-    $curr_student $prev_student $next_student 
-    $top_map @Sequences @Assessments /;
-
-#######################################################
-#######################################################
-
-=pod
-
-=item Package Variables
-
-=item @FullClasslist The full classlist
-
-=item @Students The students we are concerned with for this invocation
-
-=item @Sections The sections available in this class
-
-=item $curr_student The student currently being examined
+use Apache::lonstudentsubmissions();
+use Apache::lonsurveyreports();
+use Apache::longradinganalysis();
+use LONCAPA;
 
-=item $prev_student The student previous in the classlist
-
-=item $next_student The student next in the classlist
-
-=over
-
-=cut 
-
-#######################################################
-#######################################################
 #
 # Classlist variables
 #
-my @FullClasslist;
-my @Students;
-my @Sections;
-my @SelectedSections;
 my $curr_student;
 my $prev_student;
 my $next_student;
 
-#######################################################
-#######################################################
-
-=pod
-
-=item &clear_classlist_variables()
-
-undef the following package variables:
-
-=over
 
-=item @FullClasslist
-
-=item @Students
-
-=item @Sections
-
-=item @SelectedSections
-
-=item $curr_student
-
-=item $prev_student
-
-=item $next_student
-
-=back
-
-=cut
-
-#######################################################
-#######################################################
 sub clear_classlist_variables {
     undef(@FullClasslist);
     undef(@Students);
     undef(@Sections);
-    undef(@SelectedSections);
+    undef(@Groups);
+    undef(%StudentData);
+    undef(@SelectedStudentData);
     undef($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
-
-=item @Sections
-
-=item @SelectedSections
-
-=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 $r = shift;
     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'};
-            # Remove the empty sections
-            for (my $i=0; $i<=$#SelectedSections; $i++) {
-                if ($SelectedSections[$i] =~ /^\s*$/) {
-                    splice(@SelectedSections,$i,1);
-                }
-            }
-        } else {
-            if ($ENV{'form.Section'} !~ /^\s*$/) {
-                @SelectedSections = ($ENV{'form.Section'});
-            }
-        }
+    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($cdom,
+									$cnum);
+    my @selected_sections = &get_selected_sections();
+    my @selected_groups = &get_selected_groups();
+    #
+    # Deal with instructors with restricted section access
+    if ($env{'request.course.sec'} !~ /^\s*$/) {
+        @selected_sections = ($env{'request.course.sec'});
     }
-    @SelectedSections = ('any') if (! @SelectedSections);
     #
+    # Set up %StudentData
+    @StudentDataOrder = qw/fullname username domain id section status groups 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'}));
+    #
+    # Get groupmembership
+    my ($classgroups,$studentgroups);
+    my %curr_groups = &Apache::longroup::coursegroups($cdom,$cnum);
+    if (%curr_groups) {
+        ($classgroups,$studentgroups) = 
+	    &Apache::loncoursedata::get_group_memberships($classlist,
+                                                          $field_names,
+							  $cdom,$cnum);
+    }
+    my $now = time;
+
     # Process the classlist
     while (my ($student,$student_data) = each (%$classlist)) {
         my $studenthash = ();
         for (my $i=0; $i< scalar(@$field_names);$i++) {
-            $studenthash->{$field_names->[$i]}=$student_data->[$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'} = $length; 
+            }
+        }
+        my @studentsgroups = &Apache::loncoursedata::get_students_groups
+                                                   ($student,$enrollment_status,
+                                                    $classgroups);
+        if (@studentsgroups) {
+            $studenthash->{'groups'} = join(', ',@studentsgroups);
+            $studenthash->{'groupref'} = \@studentsgroups;
+        } else {
+            $studenthash->{'groups'} = 'none';
+            $studenthash->{'groupref'} = []; 
         }
         push (@FullClasslist,$studenthash);
         #
@@ -233,29 +164,66 @@ sub PrepareClasslist {
         $Sections{$section}++;
         #
         # Only put in the list those students we are interested in
-        foreach my $sect (@SelectedSections) {
-            if (($sect eq 'any') || ($section eq $sect)) {
-                push (@Students,$studenthash);
-                last;
+        foreach my $sect (@selected_sections) {
+            if ( (($sect eq 'all') || 
+                  ($section eq $sect)) &&
+                 (($studenthash->{'status'} eq $enrollment_status) || 
+                  ($enrollment_status eq 'Any')) 
+                 ){
+                my $groupcheck = 0;
+                if (grep(/^all$/,@selected_groups)) {
+                    push(@Students,$studenthash);
+                    last;
+                } elsif (grep(/^none$/,@selected_groups)) {
+                    if ($studenthash->{'groups'} eq 'none') {
+                        push(@Students,$studenthash);
+                        last;
+                    }     
+                } else {
+                    foreach my $group (@selected_groups) {
+                        if (grep(/^$group$/,@studentsgroups)) {
+                            push(@Students,$studenthash);
+                            $groupcheck = 1;
+                            last;
+                        }
+                    }
+                    if ($groupcheck) {
+                        last;
+                    }
+                }
             }
         }
     }
     #
     # Put the consolidated section data in the right place
-    @Sections = sort {$a cmp $b} keys(%Sections);
+    if ($env{'request.course.sec'} !~ /^\s*$/) {
+        @Sections = ($env{'request.course.sec'});
+    } else {
+        @Sections = sort {
+	    if ($a == $a && $b == $b ) { return $a <=> $b; }
+	    return $a cmp $b;
+	} keys(%Sections);
+
+        unshift(@Sections,'all'); # Put 'all' at the front of the list
+    }
+    # Sort the groups
+    @Groups = sort {$a cmp $b} keys(%{$studentgroups});
+    unshift(@Groups,'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;
-
+    $sortby = $env{'form.sort'} if (exists($env{'form.sort'}));
+    my @TmpStudents = sort { lc($a->{$sortby}) cmp lc($b->{$sortby}) ||
+                             lc($a->{'fullname'}) cmp lc($b->{'fullname'}) ||
+			     lc($a->{'username'}) cmp lc($b->{'username'}) } @Students;
     @Students = @TmpStudents;
     # 
     # Now deal with that current student thing....
-    if (exists($ENV{'form.StudentAssessmentStudent'})) {
+    $curr_student = undef;
+    if (exists($env{'form.SelectedStudent'})) {
         my ($current_uname,$current_dom) = 
-            split(':',$ENV{'form.StudentAssessmentStudent'});
+            split(':',$env{'form.SelectedStudent'});
         my $i;
         for ($i = 0; $i<=$#Students; $i++) {
             next if (($Students[$i]->{'username'} ne $current_uname) || 
@@ -263,231 +231,335 @@ sub PrepareClasslist {
             $curr_student = $Students[$i];
             last; # If we get here, we have our student.
         }
-        if ($i == 0) {
-            $prev_student = 'none';
-        } else {
-            $prev_student = $Students[$i-1];
+        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 ($i == $#Students) {
-            $next_student = 'none';
-        } else {
-            $next_student = $Students[$i+1];
+    }
+    #
+    if (exists($env{'form.StudentData'})) {
+	@SelectedStudentData = 
+	    &Apache::loncommon::get_env_multiple('form.StudentData');
+    } else {
+        @SelectedStudentData = ('username');
+    }
+    foreach (@SelectedStudentData) {
+        if ($_ eq 'all') {
+            @SelectedStudentData = ('all');
+            last;
         }
     }
+    #
+    return;
 }
 
-#######################################################
-#######################################################
-#
-# Course Sequences variables
-#
-my $top_map;
-my @Sequences;
-my @Assessments;
 
-#######################################################
-#######################################################
-
-=pod
-
-=item &clear_sequence_variables()
+sub get_selected_sections {
+    my @selected_sections = 
+	&Apache::loncommon::get_env_multiple('form.Section');
+    @selected_sections = ('all') if (! @selected_sections);
+    foreach (@selected_sections) {
+        if ($_ eq 'all') {
+            @selected_sections = ('all');
+        }
+    }
+    #
+    # Deal with instructors with restricted section access
+    if ($env{'request.course.sec'} !~ /^\s*$/) {
+        @selected_sections = ($env{'request.course.sec'});
+    }
+    return @selected_sections;
+}
 
-=cut
 
-#######################################################
-#######################################################
-sub clear_sequence_variables {
-    undef($top_map);
-    undef(@Sequences);
-    undef(@Assessments);
+sub get_selected_groups {
+    my @selected_groups =
+        &Apache::loncommon::get_env_multiple('form.Group');
+    @selected_groups = ('all') if (! @selected_groups);
+    foreach my $grp (@selected_groups) {
+        if ($grp eq 'all') {
+            @selected_groups = ('all');
+            last;
+        }
+    }
+    return @selected_groups;
 }
+                                                                                    
 
-#######################################################
-#######################################################
 
-=pod
+sub section_and_enrollment_description {
+    my ($mode) = @_;
+    if (! defined($mode)) { $mode = 'localized'; }
+    my @sections = &Apache::lonstatistics::get_selected_sections();
+    my @groups = &Apache::lonstatistics::get_selected_groups();
+    my $description;
+    if ($mode eq 'localized') {
+        $description = &mt('Unable to determine section, groups and access status');
+    } elsif ($mode eq 'plaintext') {
+        $description = 'Unable to determine section, groups and access status';
+    } else {
+        $description = 'Bad parameter passed to lonstatistics::section_and_enrollment_description';
+        &Apache::lonnet::logthis($description);
+    }
+    $description = &section_or_group_text($mode,'section',@sections).
+	' '.&section_or_group_text($mode,'group',@groups);
+    if ($mode eq 'localized') {
+        $description .= ' '.&mt($env{'form.Status'}.' access status.');
+    } elsif ($mode eq 'plaintext') {
+        $description .= ' '.$env{'form.Status'}.' access status.';
+    }
+    return $description;
+}
 
-=item &PrepareCourseData($r)
 
-=cut
 
-#######################################################
-#######################################################
-sub PrepareCourseData {
-    my ($r) = @_;
-    &clear_sequence_variables();
-    my ($top,$sequences,$assessments) = &Apache::loncoursedata::get_sequence_assessment_data();
-    if (! defined($top) || ! ref($top)) {
-        # There has been an error, better report it
-        &Apache::lonnet::logthis('top is undefined');
-        return;
-    }
-    $top_map = $top if (ref($top));
-    @Sequences = @{$sequences} if (ref($sequences) eq 'ARRAY');
-    @Assessments = @{$assessments} if (ref($assessments) eq 'HASH');
 
-=pod
-
-    ##
-    ## Debugging code
-    ##
-    foreach my $s (@Sequences) {
-        next if ($s->{'title'} ne 'Bioenergetics: Enzyme Regulation');
-        &Apache::lonnet::logthis('-----------------------------------');
-        &Apache::lonnet::logthis('title      = '.$s->{'title'});
-        &Apache::lonnet::logthis('symb       = '.$s->{'symb'});
-        &Apache::lonnet::logthis('num_assess = '.$s->{'num_assess'});
-        foreach my $a (@{$s->{'contents'}}) {
-            &Apache::lonnet::logthis('   --------------------------------');
-            &Apache::lonnet::logthis('   title      = '.$a->{'title'});
-            &Apache::lonnet::logthis('   symb       = '.$a->{'symb'});
+sub section_or_group_text {
+    my ($mode,$type,@items) = @_;
+    my $text;
+    my %phrases = ();
+    %{$phrases{'section'}} = (
+                              single => 'Section',
+                              all => 'All sections',
+                              plural => 'Sections',
+                             );
+    %{$phrases{'group'}} = (
+                              single => 'Group',
+                              all => 'All groups',
+                              plural => 'Groups',
+                             );
+    if (scalar(@items) == 1 && $items[0] ne 'all') {
+        if ($mode eq 'localized') {
+            $text = &mt($phrases{$type}{single}.' [_1].',$items[0]);
+        } elsif ($mode eq 'plaintext') {
+            $text = $phrases{$type}{single}.' '.$items[0].'.';
+
+        }
+    } elsif (scalar(@items) && $items[0] eq 'all') {
+        if ($mode eq 'localized') {
+            $text = &mt($phrases{$type}{all}.'.');
+        } elsif ($mode eq 'plaintext') {
+            $text = $phrases{$type}{all}.'.';
+        }
+    } elsif (scalar(@items)) {
+        my $lastitem = pop(@items);
+        if ($mode eq 'localized') {
+            $text = &mt($phrases{$type}{plural}.' [_1] and [_2].',
+                        join(', ',@items),$lastitem);
+        } elsif ($mode eq 'plaintext') {
+            $text = $phrases{$type}{plural}.' '.join(', ',@items).' and '.
+                    $lastitem.'.';
         }
     }
+    return $text;
+}
 
-=cut
 
-    return;
+sub get_students {
+    if (! @Students) {
+        &PrepareClasslist()
+    }
+    return @Students;
 }
 
-##############################################
-##############################################
-
-=pod 
 
-=item &MapSelect($elementname,$status,$numvisible,$selected,$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.
+sub current_student { 
+    return $curr_student;
+}
 
-=over 4
 
-=item $elementname The name of the HTML form element
 
-=item $status 'multiple' or 'single' selection box
+sub previous_student { 
+    return $prev_student;
+}
 
-=item $numvisible The number of options to be visible
 
-=item $selected Array ref to the names of the already selected maps.
-If undef, $ENV{'form.'.$elementname} is used.  
-If $ENV{'form.'.$elementname} is also empty, none will be selected.
 
-=item $restriction Code reference to subroutine which returns true or 
-false.  The code must expect a reference to a sequence data structure.
+sub next_student { 
+    return $next_student;
+}
 
-=back
 
-=cut
 
-##############################################
-##############################################
-sub MapSelect {
-    my ($elementname,$status,$numvisible,$selected,$restriction)=@_;
+sub StudentDataSelect {
+    my ($elementname,$status,$numvisible)=@_;
     if ($numvisible < 1) {
         return;
     }
     #
-    # Set up array of selected items
-    my @Selected;
-    if (! defined($selected)) {
-        if (exists($ENV{'form.'.$elementname})) {
-            if (ref($ENV{'form.'.$elementname})) {
-                @Selected = @$ENV{'form.'.$elementname};
-            } else {
-                @Selected = ($ENV{'form.'.$elementname});
-            }
-        } else {
-            @Selected = ();
-        }
-    } else {
-        if (ref($selected)) {
-            @Selected = @$selected;
-        } else {
-            @Selected = ($selected);
-        }
-    }
-    #
-    # Set up the restriction call
-    if (! defined($restriction)) {
-        $restriction = sub { 1; };
-    }
-    #
     # Build the form element
     my $Str = "\n";
     $Str .= '<select name="'.$elementname.'" ';
     if ($status ne 'single') {
-        $Str .= 'multiple="true" ';
+        $Str .= 'multiple="multiple" ';
     }
     $Str .= 'size="'.$numvisible.'" >'."\n";
     #
-    # Loop through the sequences
-    foreach my $s (@Sequences) {
-        next if (! $restriction->($s));
-        $Str .= '    <option value="'.$s->{'symb'}.'" ';
-        foreach (@Selected) {
-            if ($s->{'symb'} eq $_) {
-                $Str .= 'selected ';
+    # Deal with 'all'
+    $Str .= '    <option value="all"';
+    foreach (@SelectedStudentData) {
+        if ($_ eq 'all') {
+            $Str .= ' selected="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="selected"';
                 last;
             }
         }
-        $Str .= '>'.$s->{'title'}."</option>\n";
+        $Str .= '>'.$item."</option>\n";
     }
     $Str .= "</select>\n";
     return $Str;
 }
 
 
-##############################################
-##############################################
-
-=pod 
 
-=item &SectionSelect($elementname,$status,$numvisible) 
+sub get_selected_maps {
+    my ($elementname) = @_;
+    my @selected_maps = 
+	&Apache::loncommon::get_env_multiple('form.'.$elementname);
+    @selected_maps = ('all') if (! @selected_maps);
+    foreach my $map (@selected_maps) {
+        if ($map eq 'all') {
+            @selected_maps = ('all');
+            last;
+        }
+    }
+    return @selected_maps;
+}
 
-Returns html for a selection box allowing the user to choose one (or more) 
-of the sections in the course.  
 
-=over 4
 
-=item $elementname The name of the HTML form element
 
-=item $status 'multiple' or 'single' selection box
+sub selected_sequences_with_assessments {
+    my ($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 $toplevelseq = $navmap->getById('0.0');
+    if (!grep(/^\Q$toplevelseq\E$/,@sequences)) {
+        unshift(@sequences,$toplevelseq);
+    }
 
-=item $numvisible The number of options to be visible
+    my @sequences_with_assessments;
+    foreach my $sequence (@sequences) {
+	if ($navmap->hasResource($sequence,sub { shift->is_problem(); },0,1)){
+            push(@sequences_with_assessments,$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
+                }
+            }
+        }
 
-=item $selected Array ref to the names of the already selected sections.
-If undef, $ENV{'form.'.$elementname} is used.  
-If $ENV{'form.'.$elementname} is also empty, none will be selected.
+    }
+    return $navmap,@sequences_to_show;
+}
 
-=item $restriction Code reference to subroutine which returns true or 
-false.  The code must expect a reference to a sequence data structure.
 
-=back
+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="multiple" ';
+    }
+    $form .= 'size="'.$numvisible.'" >'."\n";
+    #
+    # Put in option for 'all'
+    $form .= '    <option value="all"';
+    if ($selected_maps[0] eq 'all') {
+        $form .= ' selected="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="selected"';
+                last;
+            }
+        }
+        $form .= '>'.$seq->compTitle."</option>\n";
+    }
+    $form .= "</select>\n";
+    return $form;
+}
 
-=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 .= 'multiple="multiple" ';
     }
     $Str .= 'size="'.$numvisible.'" >'."\n";
     #
     # Loop through the sequences
     foreach my $s (@Sections) {
-        $Str .= '    <option value="'.$s.'" ';
-        foreach (@SelectedSections) {
-            if ($s eq $_ || $_ =~ /^(any|all)$/) {
-                $Str .= 'selected ';
+        $Str .= '    <option value="'.$s.'"';
+        foreach (&get_selected_sections()) {
+            if ($s eq $_) {
+                $Str .= ' selected="selected"';
                 last;
             }
         }
@@ -497,704 +569,590 @@ sub SectionSelect {
     return $Str;
 }
 
-##############################################
-##############################################
 
-sub CheckFormElement {
-    my ($cache, $ENVName, $cacheName, $default)=@_;
-
-    if(defined($ENV{'form.'.$ENVName})) {
-        $cache->{$cacheName} = $ENV{'form.'.$ENVName};
-    } elsif(!defined($cache->{$cacheName})) {
-        $cache->{$cacheName} = $default;
-    } else {
-        $ENV{'form.'.$ENVName} = $cache->{$cacheName};
+sub GroupSelect {
+    my ($elementname,$status,$numvisible)=@_;
+    if ($numvisible < 1) {
+        return;
     }
-    return;
+    #
+    # Make sure we have the data we need to continue
+    if (! @Groups) {
+        &PrepareClasslist();
+    }
+    #
+    # Build the form element
+    my $Str = "\n";
+    $Str .= '<select name="'.$elementname.'" ';
+    if ($status ne 'single') {
+        $Str .= 'multiple="multiple" ';
+    }
+    $Str .= 'size="'.$numvisible.'" >'."\n";
+    #
+    # Loop through the groups
+    foreach my $s (@Groups) {
+        $Str .= '    <option value="'.$s.'"';
+        foreach my $group (&get_selected_groups()) {
+            if ($s eq $group) {
+                $Str .= ' selected="selected"';
+                last;
+            }
+        }
+        $Str .= '>'.$s."</option>\n";
+    }
+    $Str .= "</select>\n";
 }
 
-sub ProcessFormData{
-    my ($cache)=@_;
 
-    $cache->{'reportKey'} = 'false';
 
-    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
-                                            ['download',
-                                             'reportSelected',
-                                             'StudentAssessmentStudent',
-                                             'ProblemStatisticsSort']);
-    &CheckFormElement($cache, 'DownloadAll', 'DownloadAll', 'false');
-    if ($cache->{'DownloadAll'} ne 'false') {
-        # Clean the hell out of that cache!
-        # We cannot untie the hash at this scope (stupid libgd :( )
-        # So, remove every single key.  What a waste of time....
-        # Of course, if you are doing this you are probably resigned
-        # to waiting a while.
-        &Apache::lonnet::logthis("Cleaning out the cache file");
-        while (my ($key,undef)=each(%$cache)) {
-            next if ($key eq 'DownloadAll');
-            delete($cache->{$key});
-        }
-    }
-    &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($cache, 'sort', 'sort', 'fullname');
-    &CheckFormElement($cache, 'download', 'download', 'false');
-    &CheckFormElement($cache, 'StatisticsMaps', 
-                      'StatisticsMaps', 'All Maps');
-    &CheckFormElement($cache, 'StatisticsProblemSelect',
-		      'StatisticsProblemSelect', 'All Problems');
-    &CheckFormElement($cache, 'StatisticsPartSelect',
-		      'StatisticsPartSelect', 'All Parts');
-    if(defined($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'} = $cache->{'sectionList'};
-    }
-
-    # student assessment
-    if(defined($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($cache, 'DefaultColumns', 'DefaultColumns', 'false');
-
-    # Problem analysis
-    &CheckFormElement($cache, 'Interval', 'Interval', '1');
-
-    # ProblemStatistcs
-    &CheckFormElement($cache, 'DisplayCSVFormat',
-                      'DisplayFormat', 'Display Table Format');
-    &CheckFormElement($cache, 'ProblemStatisticsAscend',
-                      'ProblemStatisticsAscend', 'Ascending');
-    &CheckFormElement($cache, 'ProblemStatisticsSort',
-                      'ProblemStatisticsSort', 'Homework Sets Order');
-    &CheckFormElement($cache, 'DisplayLegend', 'DisplayLegend', 
-		      'Hide Legend');
-    &CheckFormElement($cache, 'SortProblems', 'SortProblems', 
-                      'Sort Within Sequence');
-
-    # 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, $_);
-                $foundColumn = 1;
+
+sub DisplayClasslist {
+    my ($r)=@_;
+    &Apache::lonhtmlcommon::add_breadcrumb
+        ({text=>'Select One Student'});
+    #
+    # Output some of the standard interface components
+    my $Str;
+    $Str .= &Apache::lonhtmlcommon::breadcrumbs('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('Groups').'</b></th>';
+    $Str .= '<th align="center"><b>'.&mt('Access Status').'</b></th>';
+    $Str .= '</tr>'.$/;
+    $Str .= '<tr>';
+    $Str .= '<td>'.
+        &Apache::lonstatistics::SectionSelect('Section','multiple',5).
+        '</td>';
+    $Str .=  '<td>'.
+        &Apache::lonstatistics::GroupSelect('Group','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','groups');
+    #
+    $Str = '';
+    my @selected_sections = &get_selected_sections();
+    if (! @Students) {
+        if ($selected_sections[0] eq 'all') { 
+            if (lc($env{'form.Status'}) eq 'active') {
+                $Str .= '<p class="LC_info">'.
+                &mt('There are no currently enrolled students in the course.').
+                    '</p>';
+            } elsif (lc($env{'form.Status'}) eq 'expired') {
+                $Str .= '<p class="LC_info">'.
+                    &mt('There are no previously enrolled students in the course.').
+                        '</p>';
+            } elsif (lc($env{'form.Status'}) eq 'future') {
+                $Str .= '<p class="LC_info">'.
+                    &mt('There are no students with future access in the course.').
+                        '</p>';
+            } else { # 'any' and any others
+               $Str .= '<p class="LC_info">'.
+                    &mt('There are no students in the course.').
+                    '</p>';
+            }
+        } else { 
+            if (lc($env{'form.Status'}) eq 'active') {
+                $Str .= '<p class="LC_info">'.
+                    &mt('There are no currently enrolled students in the selected sections.').
+                    '</p>';
+            } elsif (lc($env{'form.Status'}) eq 'expired') {
+                $Str .= '<p class="LC_info">'.
+                    &mt('There are no previously enrolled students in the selected sections.').
+                    '</p>';
+            } elsif (lc($env{'form.Status'}) eq 'future') {
+                $Str .= '<p class="LC_info">'.
+                    &mt('There are no students with future access in the selected sections.').
+                        '</p>';
+            } else { # 'any' and any others
+                $Str .= '<p class="LC_info">'.
+                    &mt('There are no students in the selected sections.').
+                    '</p>';
             }
         }
+        $Str.= '<p>'
+              .'<a href="/adm/statistics?reportSelected=student_assessment">'
+              .&mt('Return to the chart').'</a>'
+              .'</p>';
+        $r->print($Str);
+        $r->rflush();
+        return;
     }
 
-    $cache->{'reportKey'} = 'false';
-    if($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;
+    $Str .= '<h2>'.&mt('Select One Student').'</h2>'
+           .'<p>'.&mt("Click on a student's name or username to view their chart").'</p>'
+           .&Apache::loncommon::start_data_table()
+           .&Apache::loncommon::start_data_table_header_row();
+    foreach my $field (@Fields) {
+        $Str .= '<th><a href="/adm/statistics?'.
+            'reportSelected=student_assessment&'.
+            'selectstudent=1&'.
+            'sort='.$field.'">'.&mt($field).
+            '</a></th>';
+    }
+    $Str .= &Apache::loncommon::end_data_table_header_row();
+    #
+    foreach my $student (@Students) { # @Students is a package variable
+        my $sname = $student->{'username'}.':'.$student->{'domain'};
+        $Str .= &Apache::loncommon::start_data_table_row();
+        #
+        foreach my $field (@Fields) {
+            $Str .= '<td>';
+            if ($field eq 'fullname' || $field eq 'username') {
+                $Str .= '<a href="/adm/statistics?reportSelected=';
+                $Str .= &escape('student_assessment');
+                $Str .= '&sort='.&escape($env{'form.sort'});
+                $Str .= '&SelectedStudent=';
+                $Str .= &escape($sname).'">';
+                $Str .= $student->{$field}.'&nbsp;';
+                $Str .= '</a>';
+            } elsif ($field eq 'status') {
+                $Str .= &mt($student->{$field});
+            } else {
+                $Str .= $student->{$field};
+            }
+            $Str .= '</td>';
         }
+        $Str .= &Apache::loncommon::end_data_table_row();
     }
+    $Str .= &Apache::loncommon::end_data_table();
+    #
+    $r->print($Str);
+    $r->rflush();
+    #
+    return;
+}
 
-    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';
 
-    return;
+
+sub CreateMainMenu {
+    #
+    # Define menu data
+    my @reports = (
+	    {categorytitle => 'Statistics and Analyses',
+         items => [
+            {url => '/adm/statistics?reportSelected=problem_statistics',
+			 permission => 'F',
+             icon => 'document-open.png',
+             linktext => ('Overall Problem Statistics'),
+             linktitle => ('Student performance statistics on all problems.')},
+       
+            {url => '/adm/statistics?reportSelected=problem_analysis',
+			 permission => 'F',
+             icon => 'prob_ana.png',
+             linktext => ('Detailed Problem Analysis'),
+             linktitle => ('Detailed statistics and graphs of student performance on problems.')},
+         ]},
+        {categorytitle => 'Plots',
+         items => [
+            {url => '/adm/statistics?reportSelected=submissiontime_analysis',
+			 permission => 'F',
+             icon => 'subtimpl.png',
+             linktext => ('Submission Time Plots'),
+             linktitle => ('Display and analysis of submission times on assessments.')},
+      
+            {url => '/adm/statistics?reportSelected=correct_problems_plot',
+			 permission => 'F',
+             icon => 'coprplot.png',
+             linktext => ('Correct Problems Plot'),
+             linktitle => ('Display a histogram of student performance in the course.')},
+         ]},
+        {categorytitle => 'Reports',
+         items => [
+            {url => '/adm/statistics?reportSelected=student_submission_reports',
+			 permission => 'F',
+             icon => 'edit-copy.png',
+             linktext => ('Student Submission Reports'),
+             linktitle => ('Prepare reports of student submissions.')},
+                    
+            {url => '/adm/statistics?reportSelected=survey_reports',
+			 permission => 'F',
+             icon => 'survey_rep.png',
+			 linktext => ('Survey Reports'),
+             linktitle => ('Prepare reports on survey results.')},
+         ]});
+    
+return &Apache::lonhtmlcommon::generate_menu(@reports);
+ 
 }
 
+
+
+sub handler {
+    my $r=shift;
+    my $c = $r->connection();
+    #
+    # Check for access
+    if (! &Apache::lonnet::allowed('vgr',$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'}=
+                $r->uri.":vgr:0:0:Cannot view grades with given role";
+            return HTTP_NOT_ACCEPTABLE;
+        }
+    }
+    #
+    # Send the header
+    &Apache::loncommon::no_cache($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
+      
+    $r->print(&Apache::loncommon::start_page('Course Statistics and Charts',
+					     $style));
+    $r->rflush();
+    # 
+    # Either print out a menu for them or send them to a report
+    &Apache::lonhtmlcommon::clear_breadcrumbs();
+    &Apache::lonhtmlcommon::add_breadcrumb({href=>'/adm/statistics',
+                                            title=>'Statistics',
+                                            text =>'Statistics',
+                                            faq=>139,
+                                            bug=>'Statistics and Charts'});
+    if (! exists($env{'form.reportSelected'}) || 
+        $env{'form.reportSelected'} eq '') {
+        $r->print(&Apache::lonhtmlcommon::breadcrumbs('Statistics Main Page').
+                  &CreateMainMenu());
+    } else {
+    #
+        if (! &Apache::lonmysql::verify_sql_connection()) {
+            my $serveradmin = $r->dir_config('lonAdmEMail');
+            $r->print('<h2 class="LC_error">'.
+                      &mt('Unable to connect to database!').
+                      '</h2>');
+            $r->print('<p>'
+                     .&mt('Please notify the server administrator [_1]',
+                         ,'<b>'.$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>');
+            $r->print(&Apache::loncommon::end_page());
+            return;
+        }
+        #
+        # Clean out the caches
+        if (exists($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->rflush();
+        #
+        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,$c);
+        } elsif($GoToPage eq 'grading_analysis') {
+            &Apache::lonhtmlcommon::add_breadcrumb
+                ({href=>'/adm/statistics?reportselected=grading_anaylsis',
+                  text=>'Grading Analysis'});
+            &Apache::longradinganalysis::build_grading_analysis_page($r,$c);
+	}
+        #
+        $r->print("</form>\n");
+    }
+    $r->print(&Apache::loncommon::end_page());
+    $r->rflush();
+    #
+    return OK;
+}
+
+1;
+
+__END__
+
 =pod
 
-=item &SortStudents()
+=head1 NAME
 
-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.
+lonstatistics
 
-=over 4
+=head1 SYNOPSIS
 
-Input: $students, $CacheData
+Main handler for statistics and chart.
 
-$students: A array pointer to a list of students (username:domain)
+This is part of the LearningOnline Network with CAPA project
+described at http://www.lon-capa.org.
 
-$CacheData: A pointer to the hash tied to the cached data
 
-Output: \@order
+=head1 PACKAGE VARIABLES
 
-@order: An ordered list of students (username:domain)
+=over
 
-=back
+=item @FullClasslist The full classlist
 
-=cut
+=item @Students The students we are concerned with for this invocation
 
-sub SortStudents {
-    my ($cache)=@_;
+=item @Sections The sections available in this class
 
-    my @students = split(':::',$cache->{'NamesOfStudents'});
-    my @sorted1Students=();
-    foreach (@students) {
-        if($cache->{'Status'} eq 'Any' || 
-           $cache->{$_.':Status'} eq $cache->{'Status'}) {
-            push(@sorted1Students, $_);
-        }
-    }
+=item @Groups The groups available in the class
 
-    my $sortBy = '';
-    if(defined($cache->{'sort'})) {
-        $sortBy = ':'.$cache->{'sort'};
-    } else {
-        $sortBy = ':fullname';
-    }
-    my @order = sort { lc($cache->{$a.$sortBy}) cmp lc($cache->{$b.$sortBy}) ||
-                       lc($cache->{$a.':fullname'}) cmp lc($cache->{$b.':fullname'}) } 
-                @sorted1Students;
+=item $curr_student The student currently being examined
 
-    return \@order;
-}
+=item $prev_student The student previous in the classlist
 
-=pod
+=item $next_student The student next in the classlist
+
+=back
+
+=head1 SUBROUTINES
 
-=item &SpaceColumns()
+=over
 
-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.
+=item &clear_classlist_variables()
+
+undef the following package variables:
 
 =over 4
 
-Input: $students, $studentInformation, $headings, $ChartDB
+=item * @FullClasslist
+
+=item * @Students
 
-$students: An array pointer to a list of students (username:domain)
+=item * @Sections
 
-$studentInformatin: The type of data for the student information.  It is
-used as part of the key in $CacheData.
+=item * @Groups
 
-$headings: The name of the student information columns.
+=item * %StudentData
 
-$ChartDB: The name of the cache database which is opened for read/write.
+=item * @StudentDataOrder
 
-Output: None - All data stored in cache.
+=item * @SelectedStudentData
+
+=item * $curr_student
+
+=item * $prev_student
+
+=item * $next_student
 
 =back
 
-=cut
+=item &PrepareClasslist()
 
-sub SpaceColumns {
-    my ($students,$studentInformation,$headings,$cache)=@_;
+Build up the classlist information.  The classlist information is kept in
+the following package variables:
 
-    # 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;
-            }
-        }
-    }
+=over 4 
 
-    return;
-}
+=item * @FullClasslist
 
-sub PrepareData {
-    my ($c, $cacheDB, $studentInformation, $headings,$r)=@_;
+=item * @Students
 
-    # Test for access to the cache data
-    my $courseID=$ENV{'request.course.id'};
-    my $isRecalculate=0;
-    if(defined($ENV{'form.Recalculate'})) {
-        $isRecalculate=1;
-    }
+=item * @Sections
 
-    my $isCached = &Apache::loncoursedata::TestCacheData($cacheDB,
-                                                         $isRecalculate);
-    if($isCached < 0) {
-        return "Unable to tie hash to db file.";
-    }
+=item * @Groups 
 
-    # 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.";
-    }
+=item * %StudentData
 
-#    if(!$isCached) {
-        my $processTopResourceMapReturn=
-            &Apache::loncoursedata::ProcessTopResourceMap(\%cache, $c);
-        if($processTopResourceMapReturn ne 'OK') {
-            untie(%cache);
-            return $processTopResourceMapReturn;
-        }
- #   }
+=item * @SelectedStudentData
 
-    if($c->aborted()) {
-        untie(%cache);
-        return 'aborted'; 
-    }
+=item * $curr_student
 
-    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.";
-        }
-    }
+=item * $prev_student
 
-    if($c->aborted()) {
-        untie(%cache);
-        return 'aborted'; 
-    }
+=item * $next_student
 
-    # Active is a temporary solution, remember to change
-    Apache::loncoursedata::ProcessClasslist(\%cache,$classlist,$courseID,$c);
-    if($c->aborted()) {
-        untie(%cache);
-        return 'aborted'; 
-    }
+=back
 
-    &ProcessFormData(\%cache);
-    my $students = &SortStudents(\%cache);
-    &SpaceColumns($students, $studentInformation, $headings, \%cache);
-    $cache{'updateTime:columnWidth'}=24;
+$curr_student, $prev_student, and $next_student may not be defined, depending
+upon the calling context.
 
-    my $download = $cache{'download'};
-    my $downloadAll = $cache{'DownloadAll'};
-    my @allStudents=();
-    if($download ne 'false') {
-        $cache{'download'} = 'false';
-    } elsif($downloadAll ne 'false') {
-        $cache{'DownloadAll'} = 'false';
-        if($downloadAll eq 'sorted') {
-            @allStudents = @$students;
-        } else {
-            @allStudents = split(':::', $cache{'NamesOfStudents'});
-        }
-    }
+=item get_selected_sections()
 
-    untie(%cache);
+Returns an array of the selected sections
 
-    if($download ne 'false') {
-        my @who = ($download);
-        if(&Apache::loncoursedata::DownloadStudentCourseData(\@who, 'false',
-                                                             $cacheDB, 'true',
-                                                             'false', $courseID,
-                                                             $r, $c) ne 'OK') {
-            return 'Stop at download individual';
-        }
-    } elsif($downloadAll ne 'false') {
-        if(&Apache::loncoursedata::DownloadStudentCourseData(\@allStudents,
-                                                             'false',
-                                                             $cacheDB, 'true',
-                                                             'true', $courseID,
-                                                             $r, $c) ne 'OK') {
-            return 'Stop at download all';
-        }
-    }
+=item get_selected_groups()
+                                                                                    
+Returns an array of the selected groups
 
-    return ('OK', $students);
-}
+=item &section_and_enrollment_description()
 
-sub DisplayClasslist {
-    my ($r)=@_;
-    #
-    my @Fields = ('fullname','username','domain','id','section');
-    #
-    my $Str='';
-    $Str .= '<table border="0"><tr><td bgcolor="#777777">'."\n";
-    $Str .= '<table border="0" cellpadding="3"><tr bgcolor="#e6ffff">'."\n";
-    foreach my $field (@Fields) {
-        $Str .= '<th><a href="/adm/statistics?sort='.$field.'">'.$field.
-            '</a></th>';
-    }
-    $Str .= '</tr>'."\n";
-    #
-    my $alternate = 0;
-    foreach my $student (@Students) {
-        my $sname = $student->{'username'}.':'.$student->{'domain'};
-        if($alternate) {
-            $Str .= '<tr bgcolor="#ffffe6">';
-        } else {
-            $Str .= '<tr bgcolor="#ffffc6">';
-        }
-        $alternate = ($alternate + 1) % 2;
-        #
-        foreach my $field (@Fields) {
-            $Str .= '<td>';
-            if ($field eq 'fullname') {
-                $Str .= '<a href="/adm/statistics?reportSelected=';
-                $Str .= &Apache::lonnet::escape('Student Assessment');
-                $Str .= '&StudentAssessmentStudent=';
-                $Str .= &Apache::lonnet::escape($student->{$field}).'">';
-                $Str .= $student->{$field}.'&nbsp';
-                $Str .= '</a>';
-            } else {
-                $Str .= $student->{$field};
-            }
-            $Str .= '</td>';
-        }
-        $Str .= "</tr>\n";
-    }
-    $Str .= '</table></td></tr></table>'."\n";
-    #
-    $r->print($Str);
-    $r->rflush();
-    #
-    return;
-}
+Returns a string describing the currently selected section(s), group(s) and 
+access status.  
 
-sub BuildClasslist {
-    my ($cacheDB,$students,$studentInformation,$headings,$r)=@_;
+Inputs: mode = 'plaintext' or 'localized'  (defaults to 'localized')
+    'plaintext' is used for example in Excel spreadsheets.
+Returns: scalar description string.
 
-    my %cache;
-    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_READER(),0640)) {
-        return '<html><body>Unable to tie database.</body></html>';
-    }
-
-#    my $Ptr = '';
-#    $Ptr .= '<table border="0"><tbody>';
-#    $Ptr .= '<tr><td align="right"><b>Select Sections</b>';
-#    $Ptr .= '</td>'."\n";
-#    $Ptr .= '<td align="left">'."\n";
-#    my @sectionsSelected = split(':',$cache{'sectionsSelected'});
-#    my @sections = split(':',$cache{'sectionList'});
-#    $Ptr .= &Apache::lonhtmlcommon::MultipleSectionSelect(\@sections,
-#                                                          \@sectionsSelected,
-#                                                          'Statistics');
-#    $Ptr .= '</td></tr></table><br>';
-#    $r->print($Ptr);
-#    $r->rflush();
-#    my %mySections = ();
-#    foreach (@sections) { $mySections{$_} = 'True'; }
-#    $r->print("<br>$cache{'sectionsSelected'}<br>");
-
-    my $Str='';
-    $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);
-    $Str .= '</tr>'."\n";
-
-    my $alternate=0;
-    foreach (@$students) {
-#        if ($mySections{$cache{$_.':'.'section'}} ne 'True') {next;}
-        my ($username, $domain) = split(':', $_);
-        if($alternate) {
-            $Str .= '<tr bgcolor="#ffffe6">';
-        } else {
-            $Str .= '<tr bgcolor="#ffffc6">';
-        }
-        $alternate = ($alternate + 1) % 2;
-        foreach my $data (@$studentInformation) {
-            $Str .= '<td>';
-            if($data eq 'fullname') {
-                $Str .= '<a href="/adm/statistics?reportSelected=';
-                $Str .= &Apache::lonnet::escape('Student Assessment');
-                $Str .= '&StudentAssessmentStudent=';
-                $Str .= &Apache::lonnet::escape($cache{$_.':'.$data}).'">';
-                $Str .= $cache{$_.':'.$data}.'&nbsp';
-                $Str .= '</a>';
-            } elsif($data eq 'updateTime') {
-                $Str .= '<a href="/adm/statistics?reportSelected=';
-                $Str .= &Apache::lonnet::escape('Class list');
-                $Str .= '&download='.$_.'">';
-                $Str .= $cache{$_.':'.$data}.'&nbsp';
-                $Str .= '&nbsp</a>';
-            } else {
-                $Str .= $cache{$_.':'.$data}.'&nbsp';
-            }
+=item section_or_group_text()
 
-            $Str .= '</td>'."\n";
-        }
-    }
+=item get_students()
 
-    $Str .= '</tr>'."\n";
-    $Str .= '</table></td></tr></table>'."\n";
-    $r->print($Str);
-    $r->rflush();
+Returns a list of the selected students
 
-    untie(%cache);
+=item &current_student()
 
-    return;
-}
+Returns a pointer to a hash containing data about the currently
+selected student.
 
-sub CreateMainMenu {
-    my ($status, $reports)=@_;
+=item &previous_student()
 
-    my $Str = '';
+Returns a pointer to a hash containing data about the student prior
+in the list of students.  Or something. 
 
-    $Str .= '<table border="0"><tbody><tr>'."\n";
-    $Str .= '<td></td><td></td>'."\n";
-    $Str .= '<td align="center"><b>Select a Report</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";
+=item &next_student()
 
-    $Str .= '</tr></tbody></table>'."\n";
-    $Str .= '<hr>'."\n";
+Returns a pointer to a hash containing data about the next student
+to be viewed. 
 
-    return $Str;
-}
+=item &StudentDataSelect($elementname,$status,$numvisible,$selected)
 
-sub BuildStatistics {
-    my ($r)=@_;
+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)
 
-    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',
-		   'percentage'         => 'Correct-problems Plot',
-#                   '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";
-
-    $r->print(&Apache::lonhtmlcommon::Title('Course Statistics and Charts'));
-
-    my ($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'};
-        }
+=over 4
 
-        if(defined($cache{'OptionResponses'})) {
-            $reports{'problem_analysis'} = 'Option Response Analysis';
-        }
+=item * $elementname The name of the HTML form element
 
-        $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;
-    }
+=item * $status 'multiple' or 'single' selection box
 
-    if($GoToPage eq 'Activity Log') {
-        &Apache::lonproblemstatistics::Activity();
-    } elsif($GoToPage eq 'Problem Statistics') {
-        &Apache::lonproblemstatistics::BuildProblemStatisticsPage($cacheDB,
-                                                                  $students,
-                                                                  $courseID,
-                                                                  $c,$r);
-    } elsif($GoToPage eq 'Option Response Analysis') {
-        &Apache::lonproblemanalysis::BuildProblemAnalysisPage($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') {
-        my $courseDescription = $ENV{'course.'.$courseID.'.description'};
-        $courseDescription =~ s/\ /"_"/eg;
-        &Apache::lonproblemstatistics::BuildGraphicChart($GoToPage, $cacheDB,
-                                                         $courseDescription,
-                                                         $students, $courseID,
-                                                         $r, $c);
-    } elsif($GoToPage eq 'Class list') {
-        &DisplayClasslist($r);
-#        &BuildClasslist($cacheDB, $students, \@studentInformation,
-#                        \@headings, $r);
-    } elsif($GoToPage eq 'Correct-problems Plot') {
-	&Apache::lonpercentage::BuildPercentageGraph($cacheDB, $students,
-						     $courseID, $c, $r);
-    }
+=item * $numvisible The number of options to be visible
 
-    $r->print('</form>'."\n");
-    $r->print("\n".'</body>'."\n".'</html>');
-    $r->rflush();
+=back
 
-    return OK;
-}
+=item &get_selected_maps($elementname)
 
-# ================================================================ Main Handler
+Input: Name of the <select> form element used to specify the maps.
 
-sub handler {
-    my $r=shift;
+Returns: Array of symbs of selected maps or the description 'all'.
+   If form.$elementname does not exist, 'all' is returned.
 
-#    $jr = $r;
+=item &selected_sequences_with_assessments()
 
-    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 $loaderror; }
-
-    unless(&Apache::lonnet::allowed('vgr',$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;
-    }
+Retrieve the sequences which were selected by the user to show.  
 
-    unless($ENV{'request.course.fn'}) {
-	my $requrl=$r->uri;
-        $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
-        return HTTP_NOT_ACCEPTABLE;
-    }
+Input: $mode: scalar.  Either 'selected' or 'all'.  If not specified,
+    'selected' is used.
 
-    $r->content_type('text/html');
-    $r->send_http_header;
+Returns: an array containing a navmap object and navmap resources, 
+    or an array containing a scalar with an error message.
 
-    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
-                                            ['sort']);
+=item &map_select($elementname,$status,$numvisible,$restriction) 
 
-    &PrepareClasslist($r);
+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.
 
-    &PrepareCourseData($r);
+=over 4
 
-    &BuildStatistics($r);
+=item * $elementname The name of the HTML form element
 
-    return OK;
-}
-1;
+=item * $status 'multiple' or 'single' selection box
 
-=pod
+=item * $numvisible The number of options to be visible
 
 =back
 
-=cut
+=item &SectionSelect($elementname,$status,$numvisible) 
 
-__END__
+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
+
+=over 4
+
+=item * $elementname The name of the HTML form element
+
+=item * $status 'multiple' or 'single' selection box
+
+=item * $numvisible The number of options to be visible
+
+=back
+
+=item &GroupSelect($elementname,$status,$numvisible)
+                                                                                    
+Returns html for a selection box allowing the user to choose one (or more)
+of the groups in the course.
+                                                                                    
+Uses the package variables @Groups
+
+=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
+
+=item CreateMainMenu()
+
+=back
+
+=cut