--- loncom/interface/lonstatistics.pm	2003/02/28 21:19:53	1.62
+++ loncom/interface/lonstatistics.pm	2003/08/29 21:11:25	1.80
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: lonstatistics.pm,v 1.62 2003/02/28 21:19:53 matthew Exp $
+# $Id: lonstatistics.pm,v 1.80 2003/08/29 21:11:25 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -51,8 +51,7 @@ Main handler for statistics and chart.
     use Apache::lonproblemstatistics;
     use Apache::lonstudentassessment;
     use Apache::lonpercentage;
-    use GDBM_File;
-
+    use Apache::lonmysql;
 =over 4
 
 =cut
@@ -83,8 +82,8 @@ use Apache::lonproblemanalysis();
 use Apache::lonproblemstatistics();
 use Apache::lonstudentassessment();
 use Apache::lonpercentage;
-use GDBM_File;
-
+use Apache::lonmysql;
+use Time::HiRes;
 
 #######################################################
 #######################################################
@@ -207,7 +206,6 @@ upon the calling context.
 #######################################################
 #######################################################
 sub PrepareClasslist {
-    my $r = shift;
     my %Sections;
     &clear_classlist_variables();
     #
@@ -231,16 +229,23 @@ sub PrepareClasslist {
         }
     }
     #
+    # Deal with instructors with restricted section access
+    if ($ENV{'request.course.sec'} !~ /^\s*$/) {
+        @SelectedSections = ($ENV{'request.course.sec'});
+    }
+    #
     # Set up %StudentData
     @StudentDataOrder = qw/fullname username domain id section status/;
     foreach my $field (@StudentDataOrder) {
         $StudentData{$field}->{'title'} = $field;
-        $StudentData{$field}->{'base_width'} = 
-                               scalar (my @Tmp = split(//,$field));
+        $StudentData{$field}->{'base_width'} = length($field);
         $StudentData{$field}->{'width'} = 
                                $StudentData{$field}->{'base_width'};
     }
-
+    #
+    # get the status requested
+    my $requested_status = 'Active';
+    $requested_status = $ENV{'form.Status'} if (exists($ENV{'form.Status'}));
     #
     # Process the classlist
     while (my ($student,$student_data) = each (%$classlist)) {
@@ -251,7 +256,7 @@ sub PrepareClasslist {
             $studenthash->{$field}=$student_data->[$i];
             # Keep track of the width of the fields
             next if (! exists($StudentData{$field}));
-            my $length = scalar(my @Tmp1 = split(//,$student_data->[$i]));
+            my $length = length($student_data->[$i]);
             if ($StudentData{$field}->{'width'} < $length) {
                 $StudentData{$field}->{'width'} = $length; 
             }
@@ -268,7 +273,11 @@ sub PrepareClasslist {
         #
         # Only put in the list those students we are interested in
         foreach my $sect (@SelectedSections) {
-            if (($sect eq 'all') || ($section eq $sect)) {
+            if ( (($sect eq 'all') || 
+                  ($section eq $sect)) &&
+                 (($studenthash->{'status'} eq $requested_status) || 
+                  ($requested_status eq 'Any')) 
+                 ){
                 push (@Students,$studenthash);
                 last;
             }
@@ -276,8 +285,12 @@ sub PrepareClasslist {
     }
     #
     # Put the consolidated section data in the right place
-    @Sections = sort {$a cmp $b} keys(%Sections);
-    unshift(@Sections,'all'); # Put 'all' at the front of the list
+    if ($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 $sortby = 'fullname';
@@ -287,9 +300,10 @@ sub PrepareClasslist {
     @Students = @TmpStudents;
     # 
     # Now deal with that current student thing....
-    if (exists($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) || 
@@ -297,15 +311,17 @@ 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 ($i == $#Students) {
-            $next_student = 'none';
-        } else {
-            $next_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];
+            }
         }
     }
     #
@@ -316,7 +332,7 @@ sub PrepareClasslist {
             @SelectedStudentData = ($ENV{'form.StudentData'});
         }
     } else {
-        @SelectedStudentData = ('fullname');
+        @SelectedStudentData = ('username');
     }
     foreach (@SelectedStudentData) {
         if ($_ eq 'all') {
@@ -328,6 +344,27 @@ sub PrepareClasslist {
     return;
 }
 
+
+#######################################################
+#######################################################
+
+=pod
+
+=item get_students
+
+Returns a list of the selected students
+
+=cut
+
+#######################################################
+#######################################################
+sub get_students {
+    if (! @Students) {
+        &PrepareClasslist()
+    }
+    return @Students;
+}
+
 #######################################################
 #######################################################
 
@@ -343,11 +380,7 @@ selected student.
 #######################################################
 #######################################################
 sub current_student { 
-    if (defined($curr_student)) {
-        return $curr_student;
-    } else {
-        return 'All Students';
-    }
+    return $curr_student;
 }
 
 #######################################################
@@ -365,11 +398,7 @@ in the list of students.  Or something.
 #######################################################
 #######################################################
 sub previous_student { 
-    if (defined($prev_student)) {
-        return $prev_student;
-    } else {
-        return 'No Student Selected';
-    }
+    return $prev_student;
 }
 
 #######################################################
@@ -387,11 +416,7 @@ to be viewed.
 #######################################################
 #######################################################
 sub next_student { 
-    if (defined($next_student)) {
-        return $next_student;
-    } else {
-        return 'No Student Selected';
-    }
+    return $next_student;
 }
 
 #######################################################
@@ -437,6 +462,33 @@ sub SetSelectedMaps {
     }
 }
 
+
+#######################################################
+#######################################################
+
+=pod
+
+=item &Sequences_with_Assess()
+
+Returns an array containing the subset of @Sequences which contain
+assessments.
+
+=cut
+
+#######################################################
+#######################################################
+sub Sequences_with_Assess {
+    my @Sequences_to_Show;
+    foreach my $map_symb (@SelectedMaps) {
+        foreach my $sequence (@Sequences) {
+            next if ($sequence->{'symb'} ne $map_symb && $map_symb ne 'all');
+            next if ($sequence->{'num_assess'} < 1);
+            push (@Sequences_to_Show,$sequence);
+        }
+    }
+    return @Sequences_to_Show;
+}
+
 #######################################################
 #######################################################
 
@@ -464,13 +516,11 @@ sub PrepareCourseData {
     #
     # Compute column widths
     foreach my $seq (@Sequences) {
-        my $name_length = scalar(my @Tmp1 = split(//,$seq->{'title'}));
+        my $name_length = length($seq->{'title'});
         my $num_parts = $seq->{'num_assess_parts'};
         #
-        # The number of columns needed for the summation text: 
-        #    " 1/5" = 1+3 columns, " 10/99" = 1+5 columns
-        my $sum_length = 1+1+2*(scalar(my @Tmp2 = split(//,$num_parts)));
-        my $num_col = $num_parts+$sum_length;
+        # Use 3 digits for each the sum and total, which means 7 total...
+        my $num_col = $num_parts+7;
         if ($num_col < $name_length) {
             $num_col = $name_length;
         }
@@ -698,6 +748,7 @@ sub MapSelect {
 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
@@ -706,13 +757,6 @@ of the sections in the course.
 
 =item $numvisible The number of options to be visible
 
-=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.
-
-=item $restriction Code reference to subroutine which returns true or 
-false.  The code must expect a reference to a sequence data structure.
-
 =back
 
 =cut
@@ -725,6 +769,11 @@ sub SectionSelect {
         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.'" ';
@@ -748,393 +797,168 @@ 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};
-    }
-    return;
-}
-
-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;
-            }
-        }
-    }
-
-    $cache->{'reportKey'} = 'false';
-    if($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';
-
-    return;
-}
-
-##################################################
-##################################################
+#######################################################
+#######################################################
 
 =pod
 
-=item &SortStudents()
-
-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.
-
-=over 4
-
-Input: $students, $CacheData
-
-$students: A array pointer to a list of students (username:domain)
+=item &CreateAndParseOutputSelector()
 
-$CacheData: A pointer to the hash tied to the cached data
-
-Output: \@order
-
-@order: An ordered list of students (username:domain)
-
-=back
+Construct a selection list of options for output and parse output selections.
 
 =cut
 
-sub SortStudents {
-    my ($cache)=@_;
-
-    my @students = split(':::',$cache->{'NamesOfStudents'});
-    my @sorted1Students=();
-    foreach (@students) {
-        if($cache->{'Status'} eq 'Any' || 
-           $cache->{$_.':Status'} eq $cache->{'Status'}) {
-            push(@sorted1Students, $_);
-        }
-    }
-
-    my $sortBy = '';
-    if(defined($cache->{'sort'})) {
-        $sortBy = ':'.$cache->{'sort'};
-    } else {
-        $sortBy = ':fullname';
+#######################################################
+#######################################################
+sub OutputDescriptions {
+    my (@OutputOptions) = @_;
+    my $Str = '';
+    $Str .= "<h2>Output Modes</h2>\n";
+    $Str .= "<dl>\n";
+    foreach my $outputmode (@OutputOptions) {
+	$Str .="    <dt>".$outputmode->{'name'}."</dt>\n";
+	$Str .="        <dd>".$outputmode->{'description'}."</dd>\n";
     }
-    my @order = sort { lc($cache->{$a.$sortBy}) cmp lc($cache->{$b.$sortBy}) ||
-                       lc($cache->{$a.':fullname'}) cmp lc($cache->{$b.':fullname'}) } 
-                @sorted1Students;
-
-    return \@order;
+    $Str .= "</dl>\n";
+    return $Str;
 }
 
-=pod
-
-=item &SpaceColumns()
-
-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.
-
-=over 4
-
-Input: $students, $studentInformation, $headings, $ChartDB
-
-$students: An array pointer to a list of students (username:domain)
-
-$studentInformatin: The type of data for the student information.  It is
-used as part of the key in $CacheData.
-
-$headings: The name of the student information columns.
-
-$ChartDB: The name of the cache database which is opened for read/write.
-
-Output: None - All data stored in cache.
-
-=back
-
-=cut
-
-sub SpaceColumns {
-    my ($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'}=$length;
-            }
+sub CreateAndParseOutputSelector {
+    my ($elementname,$default,@OutputOptions) = @_;
+    my $output_mode;
+    my $show;
+    my $Str = '';
+    #
+    # Format for output options is 'mode, restrictions';
+    my $selected = $default;
+    if (exists($ENV{'form.'.$elementname})) {
+        if (ref($ENV{'form.'.$elementname} eq 'ARRAY')) {
+            $selected = $ENV{'form.'.$elementname}->[0];
+        } else {
+            $selected = $ENV{'form.'.$elementname};
         }
     }
-
-    return;
-}
-
-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;
-    }
-
-    my $isCached = &Apache::loncoursedata::TestCacheData($cacheDB,
-                                                         $isRecalculate);
-    if($isCached < 0) {
-        return "Unable to tie hash to db file.";
-    }
-
-    # Download class list information if not using cached data
-    my %cache;
-    unless(tie(%cache,'GDBM_File',$cacheDB,&GDBM_WRCREAT(),0640)) {
-        return "Unable to tie hash to db file.";
-    }
-
-#    if(!$isCached) {
-        my $processTopResourceMapReturn=
-            &Apache::loncoursedata::ProcessTopResourceMap(\%cache, $c);
-        if($processTopResourceMapReturn ne 'OK') {
-            untie(%cache);
-            return $processTopResourceMapReturn;
-        }
- #   }
-
-    if($c->aborted()) {
-        untie(%cache);
-        return 'aborted'; 
+    #
+    # Set package variables describing output mode
+    $output_mode = 'html';
+    $show        = 'all';
+    foreach my $option (@OutputOptions) {
+        next if ($option->{'value'} ne $selected);
+        $output_mode = $option->{'mode'};
+        $show        = $option->{'show'};
     }
-
-    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.";
-        }
+    #
+    # Build the form element
+    $Str = qq/<select size="5" name="$elementname">/;
+    foreach my $option (@OutputOptions) {
+        if (exists($option->{'special'}) && 
+            $option->{'special'} =~ /do not show/) {
+            next;
+        }
+        $Str .= "\n".'    <option value="'.$option->{'value'}.'"';
+        $Str .= " selected " if ($option->{'value'} eq $selected);
+        $Str .= ">".$option->{'name'}."<\/option>";
     }
+    $Str .= "\n</select>";
+    return ($Str,$output_mode,$show);
+}
 
-    if($c->aborted()) {
-        untie(%cache);
-        return 'aborted'; 
-    }
+###############################################
+###############################################
 
-    # Active is a temporary solution, remember to change
-    Apache::loncoursedata::ProcessClasslist(\%cache,$classlist,$courseID,$c);
-    if($c->aborted()) {
-        untie(%cache);
-        return 'aborted'; 
-    }
+=pod 
 
-    &ProcessFormData(\%cache);
-    my $students = &SortStudents(\%cache);
-    &SpaceColumns($students, $studentInformation, $headings, \%cache);
-    $cache{'updateTime:columnWidth'}=24;
+=item &Gather_Student_Data()
 
-    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'});
-        }
-    }
+Ensures all student data is up to date.
 
-    untie(%cache);
+=cut
 
-    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, $c) ne 'OK') {
-            return 'Stop at download all';
-        }
+###############################################
+###############################################
+sub Gather_Student_Data {
+    my ($r) = @_;
+    my $c = $r->connection();
+    #
+    my @Sequences = &Apache::lonstatistics::Sequences_with_Assess();
+    #
+    my @Students = @Apache::lonstatistics::Students;
+    #
+    # Open the progress window
+    my %prog_state=&Apache::lonhtmlcommon::Create_PrgWin
+        ($r,'Statistics Compilation Status',
+         'Statistics Compilation Progress', scalar(@Students));
+    #
+    while (my $student = shift @Students) {
+        return if ($c->aborted());
+        my ($status,undef) = &Apache::loncoursedata::ensure_current_data
+            ($student->{'username'},$student->{'domain'},
+             $ENV{'request.course.id'});
+        &Apache::lonhtmlcommon::Increment_PrgWin($r,\%prog_state,
+                                                 'last student');
     }
-
-    return ('OK', $students);
+    &Apache::lonhtmlcommon::Close_PrgWin($r,\%prog_state);
+    $r->rflush();
 }
 
+##################################################
+##################################################
 sub DisplayClasslist {
     my ($r)=@_;
     #
     my @Fields = ('fullname','username','domain','id','section');
     #
     my $Str='';
+    if (! @Students) {
+        if ($SelectedSections[0] eq 'all') { 
+            if (lc($ENV{'form.Status'}) eq 'any') {
+                $Str .= '<h2>There are no students in the course.</h2>';
+            } elsif (lc($ENV{'form.Status'}) eq 'active') {
+                $Str .= '<h2>There are no currently enrolled students in '.
+                    'the course.</h2>';
+            } elsif (lc($ENV{'form.Status'}) eq 'expired') {
+                $Str .= '<h2>There are no previously enrolled '.
+                    'students in the course.</h2>';
+            }
+        } else { 
+            my $sections;
+            if (@SelectedSections == 1) {
+                $sections = 'section '.$SelectedSections[0];
+            } elsif (@SelectedSections > 2) {
+                $sections = 'sections '.join(', ',@SelectedSections);
+                $sections =~ s/, ([^,])*$/, and $1/;
+            } else {
+                $sections = 'sections '.join(' and ',@SelectedSections);
+            }
+            if (lc($ENV{'form.Status'}) eq 'any') {
+                $Str .= '<h2>There are no students in '.$sections.'.</h2>';
+            } elsif (lc($ENV{'form.Status'}) eq 'active') {
+                $Str .= '<h2>There are no currently enrolled students '.
+                    'in '.$sections.'.</h2>';
+            } elsif (lc($ENV{'form.Status'}) eq 'expired') {
+                $Str .= '<h2>There are no previously enrolled students '.
+                    'in '.$sections.'.</h2>';
+            }
+        }
+        $Str.= '<a href="/adm/statistics?reportSelected=student_assessment">'.
+            'Return to the chart.</a>';
+        $r->print($Str);
+        $r->rflush();
+        return;
+    }
+
+    # "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";
     foreach my $field (@Fields) {
-        $Str .= '<th><a href="/adm/statistics?sort='.$field.'">'.$field.
+        $Str .= '<th><a href="/adm/statistics?reportSelected=classlist&sort='.$field.'">'.$field.
             '</a></th>';
     }
     $Str .= '</tr>'."\n";
     #
     my $alternate = 0;
-    foreach my $student (@Students) {
+    foreach my $student (@Students) { # @Students is a package variable
         my $sname = $student->{'username'}.':'.$student->{'domain'};
         if($alternate) {
             $Str .= '<tr bgcolor="#ffffe6">';
@@ -1145,10 +969,11 @@ sub DisplayClasslist {
         #
         foreach my $field (@Fields) {
             $Str .= '<td>';
-            if ($field 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('student_assessment');
+                $Str .= '&sort='.&Apache::lonnet::escape($ENV{'form.sort'});
+                $Str .= '&SelectedStudent=';
                 $Str .= &Apache::lonnet::escape($sname).'">';
                 $Str .= $student->{$field}.'&nbsp';
                 $Str .= '</a>';
@@ -1167,242 +992,64 @@ sub DisplayClasslist {
     return;
 }
 
-sub BuildClasslist {
-    my ($cacheDB,$students,$studentInformation,$headings,$r)=@_;
-
-    my %cache;
-    unless(tie(%cache,'GDBM_File',$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';
-            }
-
-            $Str .= '</td>'."\n";
-        }
-    }
-
-    $Str .= '</tr>'."\n";
-    $Str .= '</table></td></tr></table>'."\n";
-    $r->print($Str);
-    $r->rflush();
-
-    untie(%cache);
-
-    return;
-}
-
+##############################################
+##############################################
 sub CreateMainMenu {
-    my ($status, $reports)=@_;
-
+    my ($status,$reports,$current)=@_;
+    #
     my $Str = '';
-
-    $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";
-
-    $Str .= '</tr></tbody></table>'."\n";
-    $Str .= '<hr>'."\n";
-
+    #
+    $Str  = '<input type="hidden" name="reportSelected" value="'.$current.'">';
+#    $Str .= '<table border="0"><tbody><tr>'."\n";
+#    $Str .= '<td align="center"><b>Report:</b></td>'."\n";
+#    $Str .= '<td align="center">';
+#    $Str .= '<select name="reportSelected" '.
+#        'onchange="document.Statistics.submit()">'."\n";
+#    foreach (sort(keys(%$reports))) {
+#        $Str .= '<option value="'.$_.'"';
+#        if($current eq $_) {
+#            $Str .= ' selected';
+#        }
+#        $Str .= '>'.$reports->{$_}.'</option>'."\n";
+#    }
+#    $Str .= '</select></td>'."\n";
+#    #
+#    $Str .= '<td>'.('&nbsp;'x30).'</td>';
+#    $Str .= '<td align="center">'.
+#        '<input type="submit" name="ClearCache" value="Clear Caches" />'.
+#            "</td>\n";
+#    $Str .= '</tr></tbody></table>'."\n";
+#    $Str .= '<hr>'."\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',
-		   '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'}} = $cache{'reportSelected'};
-        }
-
-        if(defined($cache{'OptionResponses'})) {
-            $reports{'problem_analysis'} = 'Option Response Analysis';
-        }
-
-        $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($GoToPage eq 'Option Response Analysis') {
-        &Apache::lonproblemanalysis::BuildProblemAnalysisPage($cacheDB, $r);
-    } elsif($GoToPage eq 'Student Assessment') {
-        &Apache::lonstudentassessment::BuildStudentAssessmentPage($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);
-    }
-
-    $r->print('</form>'."\n");
-    $r->print("\n".'</body>'."\n".'</html>');
-    $r->rflush();
-
-    return OK;
-}
-
-# ================================================================ Main Handler
-
+##############################################
+##############################################
 sub handler {
     my $r=shift;
-
-#    $jr = $r;
-
+    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 $loaderror; }
-
-    unless(&Apache::lonnet::allowed('vgr',$ENV{'request.course.id'})) {
+    #
+    # 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";
-        return HTTP_NOT_ACCEPTABLE;
+            $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'}=
+                $r->uri.":vgr:0:0:Cannot view grades with given role";
+            return HTTP_NOT_ACCEPTABLE;
+        }
     }
-
+    #
     # Set document type for header only
     if($r->header_only) {
         if ($ENV{'browser.mathml'}) {
@@ -1414,35 +1061,99 @@ sub handler {
         $r->send_http_header;
         return OK;
     }
-
-    unless($ENV{'request.course.fn'}) {
-	my $requrl=$r->uri;
-        $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
-        return HTTP_NOT_ACCEPTABLE;
-    }
-
+    #
+    # Send the header
     $r->content_type('text/html');
     $r->send_http_header;
-
+    #
+    # Extract form elements from query string
     &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
-                                            ['sort',
-                                             'StudentAssessmentStudent']);
-
-    &PrepareClasslist($r);
-
+                                            ['sort','reportSelected',
+                                             'SelectedStudent']);
+    if (! exists($ENV{'form.reportSelected'})) {
+        $ENV{'form.reportSelected'} = 'student_assessment';
+    }
+    #
+    # Give the LON-CAPA page header
+    $r->print(&Apache::lonhtmlcommon::Title('Course Statistics and Charts'));
+    $r->rflush();
+    #
+    if (! &Apache::lonmysql::verify_sql_connection()) {
+        my $serveradmin = $r->dir_config('lonAdmEMail');
+        $r->print(<<END);
+<h2><font color="Red">Unable to connect to database!</font></h2>
+<p>
+Please notify the server administrator <b>$serveradmin</b>.
+</p><p>
+Course Statistics and Charts cannot be retrieved until the database is
+restarted.  Your data is intact but cannot be displayed at this time.
+</p>
+</body>
+</html>
+END
+        return;
+    }
+    #
+    # Clean out the caches
+    if (exists($ENV{'form.ClearCache'})) {
+        &Apache::loncoursedata::delete_caches($ENV{'requres.course.id'});
+    }
+    #
+    # Set up the statistics and chart environment
+    &PrepareClasslist();
     &PrepareCourseData($r);
-
-    &BuildStatistics($r);
-
+    #
+    # Begin form output
+    $r->print('<form name="Statistics" ');
+    $r->print('method="post" action="/adm/statistics">');
+    #
+    # Print main menu
+    my %reports = ('classlist'          => 'Class list',
+                   'problem_statistics' => 'Problem Statistics',
+                   'student_assessment' => 'Problem Status Chart',
+#                   'percentage'         => 'Correct-problems Plot',
+#                   'option_response'    => 'Option Response Analysis',
+#                   'activitylog'        => 'Activity Log',
+                   );
+    $r->print(&CreateMainMenu($ENV{'form.status'},
+                              \%reports,$ENV{'form.reportSelected'}));
+    $r->rflush();
+    #
+    my $GoToPage = $ENV{'form.reportSelected'};
+    if($GoToPage eq 'activitylog') {
+#        &Apache::lonproblemstatistics::Activity();
+    } elsif($GoToPage eq 'problem_statistics') {
+        &Apache::lonproblemstatistics::BuildProblemStatisticsPage($r,$c);
+    } elsif($GoToPage eq 'option_response') {
+#        &Apache::lonproblemanalysis::BuildProblemAnalysisPage($r,$c);
+    } elsif($GoToPage eq 'student_assessment') {
+        &Apache::lonstudentassessment::BuildStudentAssessmentPage($r,$c);
+    } elsif($GoToPage eq 'DoDiffGraph' || $GoToPage eq 'PercentWrongGraph') {
+#        &Apache::lonproblemstatistics::BuildGraphicChart($r,$c);
+    } elsif($GoToPage eq 'Correct-problems Plot') {
+#	&Apache::lonpercentage::BuildPercentageGraph($r,$c);
+    }
+    #
+    $r->print("</form>\n");
+    $r->print("</body>\n</html>\n");
+    $r->rflush();
+    #
     return OK;
 }
+
 1;
 
+#######################################################
+#######################################################
+
 =pod
 
 =back
 
 =cut
 
+#######################################################
+#######################################################
+
 __END__