--- loncom/interface/lonstatistics.pm	2002/03/22 00:18:12	1.12
+++ loncom/interface/lonstatistics.pm	2005/10/04 18:27:32	1.125
@@ -1,7 +1,6 @@
 # The LearningOnline Network with CAPA
-# (Publication Handler
 #
-# $Id: lonstatistics.pm,v 1.12 2002/03/22 00:18:12 minaeibi Exp $
+# $Id: lonstatistics.pm,v 1.125 2005/10/04 18:27:32 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -26,1272 +25,1081 @@
 # http://www.lon-capa.org/
 #
 # (Navigate problems for statistical reports
-# YEAR=2001
-# 5/05,7/09,7/25/01,8/11,9/13,9/26,10/5,10/9,10/22,10/26 Behrouz Minaei
-# 11/1, 11/4, 11/16, 12/14, 12/16, 12/18,12/20,12/31 Behrouz Minaei
-# YEAR=2002
-# 1/22, 2/1, 2/6, 2/25, 3/2, 3/6, 3/17, 3/21 Behrouz Minaei
+#
 ###
 
-package Apache::lonstatistics; 
+=pod
+
+=head1 NAME
+
+lonstatistics
+
+=head1 SYNOPSIS
+
+Main handler for statistics and chart.
+
+=over 4
+
+=cut
+
+package Apache::lonstatistics;
 
 use strict;
 use Apache::Constants qw(:common :http);
-use Apache::lonnet();
+use vars qw(
+    @FullClasslist 
+    @Students
+    @Sections 
+    %StudentData
+    @StudentDataOrder
+    @SelectedStudentData
+    $enrollment_status);
+
+use Apache::lonnet;
 use Apache::lonhomework;
 use Apache::loncommon;
-use HTML::TokeParser;
-use GDBM_File;
+use Apache::loncoursedata;
+use Apache::lonhtmlcommon;
+use Apache::lonmysql;
+use Apache::lonlocal;
+use Time::HiRes;
+#
+# Statistics Packages
+use Apache::lonproblemanalysis();
+use Apache::lonsubmissiontimeanalysis();
+use Apache::loncorrectproblemplot();
+use Apache::lonproblemstatistics();
+use Apache::lonstudentassessment();
+use Apache::lonpercentage;
+use Apache::lonstudentsubmissions();
+use Apache::lonsurveyreports();
 
-# -------------------------------------------------------------- Module Globals
-my %hash;
-my %CachData;
-my %GraphDat;
-my %OpResp;
-my %maps;
-my %mapsort;
-my %section;
-my %StuBox;
-my %DiscFac;
-my %DisUp;
-my %DisLow;
-my $UpCnt;
-my $CurMap;
-my $CurSec;
-my $CurStu;
-my @cols;
-my @list;
-my @students;
-my $p_count;
-my $Pos;
-my $r;
-my $OpSel1;
-my $OpSel2;
-my $OpSelDis1;
-my $OpSelDis2;
-my $OpSel3;
-my $OpSel4;
-my $GData;
-my $cid;
-my $firstres;
-my $lastres;
-my $DiscFlag;
-my $HWN;
-my $P_Order;
-my %Header = (0,"Homework Sets Order",1,"#Stdnts",2,"Tries",3,"Mod",
-              4,"Mean",5,"#YES",6,"#yes",7,"%Wrng",8,"DoDiff",
-              9,"S.D.",10,"Skew.",11,"D.F.1st",12,"D.F.2nd");#,13,"OpResp");
-
-
-#------- Processing upperlist and lowerlist according to each problem
-sub ProcessDisc {
-    my @List = @_;
-    @List = sort (@List);
-    my $Count = $#List+1;
-    my $Prb;
-    my @Dis;
-    my $Slvd=0;
-    my $tmp;
-    my $Sum1=0;
-    my $Sum2=0;
-    my $nIdx=0;
-    my $nStud=0;
-    my %Proc;
-    undef %Proc;
-    while ($nIdx<$Count) {
-	($Prb,$tmp)=split(/\=/,$List[$nIdx]);
-	@Dis=split(/\+/,$tmp);
-	my $Temp = $Prb;
-	do {
-	    $nIdx++;
-	    $nStud++;
-	    $Sum1 += $Dis[0];
-	    $Sum2 += $Dis[1];
-	    ($Prb,$tmp)=split(/\=/,$List[$nIdx]);
-	    @Dis=split(/\+/,$tmp);
-	} while ( $Prb eq $Temp && $nIdx < $Count );
-#	$Proc{$Temp}=($Sum1/$nStud).':'.$nStud;
-	$Proc{$Temp}=($Sum1/$nStud).':'.($Sum2/$nStud);
-#        $r->print("$nIdx) $Temp --> ($nStud) $Proc{$Temp} <br>");
-	$Sum1=0;
-	$Sum2=0;
-	$nStud=0;
-    }
-    return %Proc;
-}
+#######################################################
+#######################################################
 
+=pod
 
-#------- Creating Discimination factor   
-sub Discriminant {
-    my $Count=0;
-    foreach (keys(%DiscFac)){ 
-	$Count++;
-    }
-    $UpCnt = int(0.27*$Count);
-    my $low=0;
-    my $up=$Count-$UpCnt;
-    my @UpList=();
-    my @LowList=();
-    $Count=0;
-    foreach my $key (sort(keys(%DiscFac))){ 
-	$Count++;    
-        #$r->print("<br>$Count) $key = $DiscFac{$key}");
-	if ($low < $UpCnt || $Count > $up) {
-	    $low++;
-	    my $str=$DiscFac{$key};
-	    foreach(split(/\:/,$str)){
-		if ($_) {
-		    if ($low<$UpCnt){push(@LowList,$_);}
-		    else {push(@UpList,$_);}
-		}
-	    }
-	}
-    }
-    %DisUp=&ProcessDisc(@UpList);
-    %DisLow=&ProcessDisc(@LowList);
-}
+=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
 
-   
-sub NumericSort {          
-    $a <=> $b;
+=item $prev_student The student previous in the classlist
+
+=item $next_student The student next in the classlist
+
+=over
+
+=cut 
+
+#######################################################
+#######################################################
+#
+# Classlist variables
+#
+my $curr_student;
+my $prev_student;
+my $next_student;
+
+#######################################################
+#######################################################
+
+=pod
+
+=item &clear_classlist_variables()
+
+undef the following package variables:
+
+=over
+
+=item @FullClasslist
+
+=item @Students
+
+=item @Sections
+
+=item %StudentData
+
+=item @StudentDataOrder
+
+=item @SelectedStudentData
+
+=item $curr_student
+
+=item $prev_student
+
+=item $next_student
+
+=back
+
+=cut
+
+#######################################################
+#######################################################
+sub clear_classlist_variables {
+    undef(@FullClasslist);
+    undef(@Students);
+    undef(@Sections);
+    undef(%StudentData);
+    undef(@SelectedStudentData);
+    undef($curr_student);
+    undef($prev_student);
+    undef($next_student);
 }
 
-# ------ Create different Student Report 
-sub StudentReport {
+#######################################################
+#######################################################
 
-    my ($sname,$sdom)=@_;
+=pod
 
-    if ( $sname eq 'All Students' ) {
-	$r->print( '<h3><font color=blue>WARNING: 
-                    Please select a student</font></h3>' );
-	return;
-    }
-    my $shome=&Apache::lonnet::homeserver($sname,$sdom);          
-    my $reply=&Apache::lonnet::reply('dump:'.$sdom.':'.$sname.':'.$cid,$shome );
-    my %result = ();
-    my $ResId;
-    my $PrOrd;
-    my $Code;
-    my $Tries;
-    my $TotalTries = 0;
-    my $ParCr = 0;
-    my $Wrongs;
-    my %TempHash;
-    my $Version;
-    my $LatestVersion;
-    my $PtrTry='';
-    my $PtrCod='';
-    my $SetNo=0;
-    my $Str = "\n".'<table border=2>'.
-              "\n".'<tr>'.
-              "\n".'<th> # </th>'.
-	      "\n".'<th> Set Title </th>'.
-	      "\n".'<th> Results </th>'.
-	      "\n".'<th> Tries </th>'.
-	      "\n".'</tr>';
-    unless ($reply=~/^error\:/) {
-        foreach (split(/\&/,$reply)){
-            my ($name,$value)=split(/\=/,&Apache::lonnet::unescape($_));
-            $result{$name}=$value;
-        }
-        foreach my $CurCol (@cols) {
-	    if (!$CurCol){
-		my $Set=&Apache::lonnet::declutter($hash{'map_id_'.$1});
-		if ( $Set ) {
-		    $SetNo++;
-		    $Str .= "\n"."<tr>".
-			    "\n"."<td> $SetNo </td>".
-                            "\n"."<td> $Set </td>".
-                            "\n"."<td> $PtrCod </td>".
-                            "\n"."<td> $PtrTry</td>".
-                            "\n"."</tr>";
-		}
-		$PtrTry='';
-		$PtrCod='';
-		next; 
-	    }
-	    ($PrOrd,$ResId)=split(/\:/,$CurCol);
-            $ResId=~/(\d+)\.(\d+)/;
-            my $Map = &Apache::lonnet::declutter( $hash{'map_id_'.$1} );
-            if ( $CurMap ne 'All Maps' ) {
-		my ( $ResMap, $NameMap ) = split(/\=/,$CurMap);
-		if ( $Map ne $ResMap ) { next; }
-	    }
-	    my $meta=$hash{'src_'.$ResId};
-	    my $PartNo = 0;
-	    undef %TempHash;
-	    foreach (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))){
-		if ($_=~/^stores\_(\w+)\_tries$/) {
-                    my $Part=&Apache::lonnet::metadata($meta,$_.'.part');
-		    if ( $TempHash{"$Part"} eq '' ) { 
-			$TempHash{"$Part"} = $Part;
-			$TempHash{$PartNo}=$Part;
-			$TempHash{"$Part.Code"} = '-';  
-			$TempHash{"$Part.PrOrd"} = $PrOrd+$PartNo;  
-			$PartNo++;
-		    }
-		}
-		#if ($_=~/^parameter\_(\w+)\_package$/) {
-            }
+=item &PrepareClasslist()
 
-            my $Prob = $Map.'___'.$2.'___'.
-                       &Apache::lonnet::declutter( $hash{'src_'.$ResId} );
-            $Code='U';
-            $Tries = 0;
-            $Wrongs = 0;
-  	    $LatestVersion = $result{"version:$Prob"};
-	    if ( $LatestVersion ) {
-		for ( my $Version=1; $Version<=$LatestVersion; $Version++ ) {
-		    my $vkeys = $result{"$Version:keys:$Prob"};
-		    my @keys = split(/\:/,$vkeys);		
-  
-		    foreach my $Key (@keys) {		  
-			if (($Key=~/\.(\w+)\.solved$/) && ($Key!~/^\d+\:/)) {
-			    my $Part = $1;
-			    $Tries = $result{"$Version:$Prob:resource.$Part.tries"};
-			    $TempHash{"$Part.Tries"} = ($Tries) ? $Tries : 0; 
-			    $TotalTries += $Tries;
-			    my $Val = $result{"$Version:$Prob:resource.$Part.solved"};
-			    if ( $Val eq 'correct_by_student' )
-                                { $Wrongs = $Tries - 1; $Code = 'Y'; } 
-			    elsif ( $Val eq 'correct_by_override' )
-                                { $Wrongs = $Tries - 1; $Code = 'y'; }                        
-			    elsif ( $Val eq 'incorrect_attempted' || 
-                                $Val eq 'incorrect_by_override' )
-		                { $Wrongs = $Tries; $Code = 'N'; }
-			    $TempHash{"$Part.Code"} = $Code;
-			    $TempHash{"$Part.Wrongs"} = $Wrongs;
-			}
-     		    }
-                }
-		for ( my $n = 0; $n < $PartNo; $n++ ) {		  
-		    my $part = $TempHash{$n};
-		    if ($PtrTry ne '') {$PtrTry .= ',';}
-		    $PtrTry .= "$TempHash{$part.'.Tries'}";
-                    $PtrCod .= "$TempHash{$part.'.Code'}";    
-		}
+Build up the classlist information.  The classlist information is kept in
+the following package variables:
+
+=over
+
+=item @FullClasslist
+
+=item @Students
+
+=item @Sections
+
+=item %StudentData
+
+=item @SelectedStudentData
+
+=item $curr_student
+
+=item $prev_student
+
+=item $next_student
+
+=back
+
+$curr_student, $prev_student, and $next_student may not be defined, depending
+upon the calling context.
+
+=cut
+
+#######################################################
+#######################################################
+sub PrepareClasslist {
+    my %Sections;
+    &clear_classlist_variables();
+    #
+    # Retrieve the classlist
+    my $cid  = $env{'request.course.id'};
+    my $cdom = $env{'course.'.$cid.'.domain'};
+    my $cnum = $env{'course.'.$cid.'.num'};
+    my ($classlist,$field_names) = &Apache::loncoursedata::get_classlist($cdom,
+									$cnum);
+    my @selected_sections = &get_selected_sections();
+    #
+    # Deal with instructors with restricted section access
+    if ($env{'request.course.sec'} !~ /^\s*$/) {
+        @selected_sections = ($env{'request.course.sec'});
+    }
+    #
+    # Set up %StudentData
+    @StudentDataOrder = qw/fullname username domain id section status comments/;
+    foreach my $field (@StudentDataOrder) {
+        $StudentData{$field}->{'title'} = &mt($field);
+        $StudentData{$field}->{'base_width'} = length(&mt($field));
+        $StudentData{$field}->{'width'} = 
+                               $StudentData{$field}->{'base_width'};
+    }
+    #
+    # get the status requested
+    $enrollment_status = 'Active';
+    $enrollment_status = $env{'form.Status'} if (exists($env{'form.Status'}));
+    #
+    # Process the classlist
+    while (my ($student,$student_data) = each (%$classlist)) {
+        my $studenthash = ();
+        for (my $i=0; $i< scalar(@$field_names);$i++) {
+            my $field = $field_names->[$i];
+            # Store the data
+            $studenthash->{$field}=$student_data->[$i];
+            # Keep track of the width of the fields
+            next if (! exists($StudentData{$field}));
+            my $length = length($student_data->[$i]);
+            if ($StudentData{$field}->{'width'} < $length) {
+                $StudentData{$field}->{'width'} = $length; 
+            }
+        }
+        push (@FullClasslist,$studenthash);
+        #
+        # Build up a list of sections
+        my $section = $studenthash->{'section'};
+        if (! defined($section) || $section =~/^\s*$/ || $section == -1) {
+            $studenthash->{'section'} = 'none';
+            $section = $studenthash->{'section'};
+        }
+        $Sections{$section}++;
+        #
+        # Only put in the list those students we are interested in
+        foreach my $sect (@selected_sections) {
+            if ( (($sect eq 'all') || 
+                  ($section eq $sect)) &&
+                 (($studenthash->{'status'} eq $enrollment_status) || 
+                  ($enrollment_status eq 'Any')) 
+                 ){
+                push (@Students,$studenthash);
+                last;
             }
-	    else { 
-		for(my $n=0; $n<$PartNo; $n++) { 
-		    if ($PtrTry ne '') {$PtrTry .= ',';}
-		    $PtrTry .= "0";
-                    $PtrCod .= "-"; 
-		}
-	    }
         }
     }
-    $Str .= "\n".'</table>';
-    $r->print($Str);
-    $r->rflush();
-}
-
-sub CreateTable {
-    my $ColNo=0;
-    foreach (keys(%Header)){ 
-	$ColNo++;
-    } 
-    my ($Hd, $Hid)=@_;
-    if ( $Hd == 1 ) {
-	$r->print('<br><a href="'.$hash{'src_'.$Hid}.
-                  '" target="_blank">'.$hash{'title_'.$Hid}.'</a>');
-    }
-    my $Result = "\n".'<table border=2>';
-    $Result .= '<tr><th>P#</th>'."\n";
-    for ( my $nIdx=0; $nIdx < $ColNo; $nIdx++ ) { 
-	$Result .= '<th>'.'<input type="submit" name="sort" value="'.
-                   $Header{$nIdx}.'" />'.'</th>'."\n";
+    #
+    # Put the consolidated section data in the right place
+    if ($env{'request.course.sec'} !~ /^\s*$/) {
+        @Sections = ($env{'request.course.sec'});
+    } else {
+        @Sections = sort {$a cmp $b} keys(%Sections);
+        unshift(@Sections,'all'); # Put 'all' at the front of the list
+    }
+    #
+    # Sort the Students
+    my $sortby = 'fullname';
+    $sortby = $env{'form.sort'} if (exists($env{'form.sort'}));
+    my @TmpStudents = sort { $a->{$sortby} cmp $b->{$sortby} ||
+                             $a->{'fullname'} cmp $b->{'fullname'} } @Students;
+    @Students = @TmpStudents;
+    # 
+    # Now deal with that current student thing....
+    $curr_student = undef;
+    if (exists($env{'form.SelectedStudent'})) {
+        my ($current_uname,$current_dom) = 
+            split(':',$env{'form.SelectedStudent'});
+        my $i;
+        for ($i = 0; $i<=$#Students; $i++) {
+            next if (($Students[$i]->{'username'} ne $current_uname) || 
+                     ($Students[$i]->{'domain'}   ne $current_dom));
+            $curr_student = $Students[$i];
+            last; # If we get here, we have our student.
+        }
+        if (defined($curr_student)) {
+            if ($i == 0) {
+                $prev_student = undef;
+            } else {
+                $prev_student = $Students[$i-1];
+            }
+            if ($i == $#Students) {
+                $next_student = undef;
+            } else {
+                $next_student = $Students[$i+1];
+            }
+        }
     }
-    $Result .= "\n".'</tr>'."\n";    
-    $r->print( $Result );
-    $r->rflush();
+    #
+    if (exists($env{'form.StudentData'})) {
+	@SelectedStudentData = 
+	    &Apache::loncommon::get_env_multiple('form.StudentData');
+    } else {
+        @SelectedStudentData = ('username');
+    }
+    foreach (@SelectedStudentData) {
+        if ($_ eq 'all') {
+            @SelectedStudentData = ('all');
+            last;
+        }
+    }
+    #
+    return;
 }
 
-sub CloseTable {
-    $r->print("\n".'</table>'."\n");
-    $r->rflush();
-}
- 
-# ------------------------------------------- Prepare Statistics Table
-sub PreStatTable {
-    my $CacheDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
-                  "_$ENV{'user.domain'}_$cid\_statistics.db";
-    my $GraphDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
-                  "_$ENV{'user.domain'}_$cid\_graph.db";
-    my $OpSel11='';
-    my $OpSel12='';
-    my $OpSel13='';
-    my $Status = $ENV{'form.status'};
-    if ( $Status eq 'Any' ) { $OpSel13='selected'; }
-    elsif ($Status eq 'Expired' ) { $OpSel12 = 'selected'; }
-    else { $OpSel11 = 'selected'; }
-
-    my $Ptr = '';
-    $Ptr .= '<br><b> Student Status: &nbsp; </b>'."\n".
-            '<select name="status">'. 
-            '<option '.$OpSel11.' >Active</option>'."\n".
-            '<option '.$OpSel12.' >Expired</option>'."\n".
-	    '<option '.$OpSel13.' >Any</option> </select> '."\n";
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
-    $Ptr .= '<input type=submit name=sort value="Recalculate Statistics"/>'."\n";
-
-    $Ptr .= '<br><b> Sorting Type: &nbsp; </b>'."\n".
-            '<select name="order"> <option '.$OpSel1.' >Ascending</option>'."\n".
-	    '<option '.$OpSel2.'>Descending</option> </select> '."\n";
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
-    $Ptr .= '<input type="submit" name="sort" value="DoDiff Graph" />'."\n";
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
-    $Ptr .= '<input type="submit" name="sort" value="%Wrong Graph" />'."\n";
-
-    $Ptr .= '<pre>'.
-    '<b>  #Stdnts</b>: Total Number of Students opened the problem.<br>'. 
-    '<b>  Tries  </b>: Total Number of Tries for solving the problem.<br>'. 
-    '<b>  Mod   </b> : Maximunm Number of Tries for solving the problem.<br>'. 
-    '<b>  Mean   </b>: Average Number of the tries. [ Tries / #Stdnts ]<br>'.
-    '<b>  #YES   </b>: Number of students solved the problem correctly.<br>'. 
-    '<b>  #yes   </b>: Number of students solved the problem by override.<br>'.
-    '<b>  %Wrng  </b>: Percentage of students tried to solve the problem but'.
-    ' still incorrect. [ 100*((#Stdnts-(#YES+#yes))/#Stdnts) ]<br>'.
-#    '  DoDiff : Degree of Difficulty of the problem. [ Tries/(#YES+#yes+0.1) ]<br>'. Kashy formula
-    '<b>  DoDiff </b>: Degree of Difficulty of the problem. [ 1 - ((#YES+#yes) / Tries) ]<br>'. #Gerd formula
-    '<b>  S.D.  </b> : Standard Deviation of the tries.'.
-    '[ sqrt(sum((Xi - Mean)^2)) / (#Stdnts-1)'.
-    ' where Xi denotes every student\'s tries ]<br>'.
-    '<b>  Skew.  </b>: Skewness of the students tries.'.
-	' [ (sqrt( sum((Xi - Mean)^3) / #Stdnts)) / (S.D.^3) ]<br>'.
-    '<b>  Dis.F. </b>: Discrimination Factor: A Standard for '.
-	'evaluating the problem according to a Criterion<br>'.
-	'<b>           [Applied Criterion in %27 Upper Students - '.
-	'Applied the same Criterion in %27 Lower Students]</b><br>'.
-    '<b>           1st </b>Criterion for Sorting the Students: '.
-	'Sum of Partial Credit Awarded / Total Number of Tries<br>'.
-    '<b>           2nd </b>Criterion for Sorting the Students: '.
-	'Total number of Correct Answers / Total Number of Tries'.	
-            '</pre>';
-
-    $r->print($Ptr);
-    $r->rflush();	
-
-    if ((-e "$CacheDB")&&($ENV{'form.sort'} ne 'Recalculate Statistics')) {
-	if (tie(%CachData,'GDBM_File',"$CacheDB",&GDBM_READER,0640)) {
-	    tie(%GraphDat,'GDBM_File',$GraphDB,&GDBM_WRCREAT,0640);
-	    &Cache_Statistics();
-        }
-        else {
-	    $r->print("Unable to tie hash to db file");
-        }
-    }
-    else {
-	if (tie(%CachData,'GDBM_File',$CacheDB,&GDBM_WRCREAT,0640)) {
-	    tie(%GraphDat,'GDBM_File',$GraphDB,&GDBM_WRCREAT,0640);
-	    foreach (keys %DiscFac) {delete $CachData{$_};}
-	    foreach (keys %CachData) {delete $CachData{$_};}
-	    $DiscFlag=0;
-	    &Build_Statistics();
-	}
-        else {
-	    $r->print("Unable to tie hash to db file");
-        }
-    }
-
-#33333
-#    my $c=0;
-#    foreach (sort keys %OpResp) {
-#	$r->print('<br>'.$c.$_.' ====== '.$OpResp{$_});
-#	my $count=$#students+1;
-#	for (my $n=0;$n<1;$n++){
-#	    my ($sname,$sdom)=$students[$n];
-#	    my $Prob=$OpResp{$_};
-##my $userview=&Apache::lonnet::ssi($hash{'src_'.$ResId});
-#		$r->print('<br>'.$Prob.$sname.$sdom.$cid.
-#			  '<br>'.&Apache::loncommon::get_previous_attempt($Prob,$sname,$sdom,$cid));
-#		#$r->print('<br>'.$Prob.$sname. ' *** '.&Apache::lonnet::ssi($hash{'src_'.$Prob})); 
-#	}
-#	$c++;
-#    }
+#######################################################
+#######################################################
 
-    #$r->print('Total instances of the problems : '.($p_count*($#students+1)));
+=pod
 
-    untie(%CachData);
-    untie(%GraphDat);
-}
+=item get_selected_sections
 
+Returns an array of the selected sections
 
-# ------------------------------------- Find the section of student in a course
+=cut
 
-sub usection {
-    my ($udom,$unam,$courseid,$ActiveFlag)=@_;
-    $courseid=~s/\_/\//g;
-    $courseid=~s/^(\w)/\/$1/;
-    foreach (split(/\&/,&Apache::lonnet::reply('dump:'.
-             $udom.':'.$unam.':roles',
-             &Apache::lonnet::homeserver($unam,$udom)))){
-        my ($key,$value)=split(/\=/,$_);
-        $key=&Apache::lonnet::unescape($key);
-        if ($key=~/^$courseid(?:\/)*(\w+)*\_st$/) {
-            my $section=$1;
-            if ($key eq $courseid.'_st') { $section=''; }
-	    my ($dummy,$end,$start)=split(/\_/,&Apache::lonnet::unescape($value));
-	    if ( $ActiveFlag ne 'Any' ) {
-		my $now=time;
-		my $notactive=0;
-		if ($start) {
-		    if ($now<$start) { $notactive=1; }
-		}
-		if ($end) {
-		    if ($now>$end) { $notactive=1; }
-		}
-		if ((($ActiveFlag eq 'Expired') && $notactive == 1) || 
-                    (($ActiveFlag eq 'Active') && $notactive == 0 ) ) {
-		    return $section;
-		}
-		else { return '-1'; } 
-	    }
-	    return $section;
+#######################################################
+#######################################################
+sub get_selected_sections {
+    my @selected_sections = 
+	&Apache::loncommon::get_env_multiple('form.Section');
+    @selected_sections = ('all') if (! @selected_sections);
+    foreach (@selected_sections) {
+        if ($_ eq 'all') {
+            @selected_sections = ('all');
+        }
+    }
+    #
+    # Deal with instructors with restricted section access
+    if ($env{'request.course.sec'} !~ /^\s*$/) {
+        @selected_sections = ($env{'request.course.sec'});
+    }
+    return @selected_sections;
+}
+
+#######################################################
+#######################################################
+
+=pod
+
+=item &section_and_enrollment_description
+
+Returns a string describing the currenly selected section(s) and 
+enrollment status.  
+
+Inputs: mode = 'plaintext' or 'localized'  (defaults to 'localized')
+    'plaintext' is used for example in Excel spreadsheets.
+Returns: scalar description string.
+
+=cut
+
+#######################################################
+#######################################################
+sub section_and_enrollment_description {
+    my ($mode) = @_;
+    if (! defined($mode)) { $mode = 'localized'; }
+    my @sections = &Apache::lonstatistics::get_selected_sections();
+    my $description;
+    if ($mode eq 'localized') {
+        $description = &mt('Unable to determine section and enrollment');
+    } elsif ($mode eq 'plaintext') {
+        $description = 'Unable to determine section and enrollment';
+    } else {
+        $description = 'Bad parameter passed to lonstatistics::section_and_enrollment_description';
+        &Apache::lonnet::logthis($description);
+    }
+    if (scalar(@sections) == 1 && $sections[0] ne 'all') {
+        if ($mode eq 'localized') {
+            $description = &mt('Section [_1]. [_2] enrollment status.',
+                               $sections[0],$env{'form.Status'});
+        } elsif ($mode eq 'plaintext') {
+            $description = 'Section '.$sections[0].'. '.
+                $env{'form.Status'}.' enrollment status.';
+        }
+    } elsif (scalar(@sections) && $sections[0] eq 'all') {
+        if ($mode eq 'localized') {
+            $description = &mt('All sections. [_1] enrollment status.',
+                               $env{'form.Status'});
+        } elsif ($mode eq 'plaintext') {
+            $description = 'All sections. '.
+                $env{'form.Status'}.' enrollment status.';
+        }
+    } elsif (scalar(@sections)) {
+        my $lastsection = pop(@sections);
+        if ($mode eq 'localized') {
+            $description = &mt('Sections [_1] and [_2]. [_3] enrollment status.',
+                               join(', ',@sections),$lastsection,
+                               $env{'form.Status'});
+        } elsif ($mode eq 'plaintext') {
+            $description = 
+                'Sections '.join(', ',@sections).' and '.$lastsection.'. '.
+                $env{'form.Status'}.' enrollment status.';
         }
     }
-    return '-1';
+    return $description;
 }
 
+#######################################################
+#######################################################
 
-# ------ Dump the Student's DB file and handling the data for statistics table 
+=pod
 
-sub ExtractStudentData {
-    my ($student,$coid)=@_;
-    my ($sname,$sdom) = split( /\:/, $student );
-    my $shome=&Apache::lonnet::homeserver( $sname,$sdom );          
-    my $reply=&Apache::lonnet::reply('dump:'.$sdom.':'.$sname.':'.$coid,$shome );
-    my %result = ();
-    my $ResId;
-    my $PrOrd;
-    my $Dis = '';
-    my $Code;
-    my $Tries;
-    my $ParCr;
-    my $TotalTries = 0;
-    my $TotalOpend = 0;
-    my $ProbSolved = 0;
-    my $ProbTot = 0;
-    my $TimeTot = 0;
-    my $TotParCr = 0;
-    my $Wrongs;
-    my %TempHash;
-    my $Version;
-    my $LatestVersion;
-    my $SecLimit;
-    my $MapLimit;
-    unless ($reply=~/^error\:/) {
-        foreach (split(/\&/,$reply)) {
-            my ($name,$value)=split(/\=/,&Apache::lonnet::unescape($_));
-            $result{$name}=$value;
-        }
-        foreach my $CurCol(@cols) {
-	    ($PrOrd,$ResId)=split(/\:/,$CurCol);
-	    if ( !$CurCol ) { next; }
-            $ResId=~/(\d+)\.(\d+)/;
-	    my $MapId=$1;
-	    my $PrbId=$2;
-            my $Map = &Apache::lonnet::declutter( $hash{'map_id_'.$MapId} );
-            if ( $CurMap ne 'All Maps' ) {
-		my ( $ResMap, $NameMap ) = split(/\=/,$CurMap);
-		if ( $Map ne $ResMap ) { next; }
-	    }
-	    my $meta=$hash{'src_'.$ResId};
-	    my $PartNo = 0;
-	    $Dis .= ':';
-	    undef %TempHash;
-
-	    foreach (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))) { 
-		if ($_=~/^stores\_(\w+)\_tries$/) {
-                    my $Part=&Apache::lonnet::metadata($meta,$_.'.part');
-		    if ( $TempHash{"$Part"} eq '' ) { 
-			$TempHash{"$Part"} = $Part;
-			$TempHash{$PartNo}=$Part;
-			$TempHash{"$Part.Code"} = 'U';  
-			$TempHash{"$Part.PrOrd"} = $PrOrd+$PartNo;
-			$PartNo++;
-		    }
-                    my $Part=&Apache::lonnet::metadata($meta,$_.'.part');
-		}
-            }
+=item get_students
 
-            my $Prob = $Map.'___'.$PrbId.'___'.
-                       &Apache::lonnet::declutter( $hash{'src_'.$ResId} );
-	    $OpResp{$PrOrd}=$Prob;
-            $Code='U';
-            $Tries = 0;
-	    $ParCr = 0;
-            $Wrongs = 0;
-  	    $LatestVersion = $result{"version:$Prob"};       
-
-	    if ( $LatestVersion ) {
-#333333333
-#my $userview=&Apache::lonnet::ssi($hash{'src_'.$ResId});
-#$r->print('<br>'.$userview); 
-#$r->print('<br>'.$Prob.$sname.$sdom.$coid.'<br>'.&get_student_answers($Prob,$sname,$sdom,$coid)); 
-
-		for ( my $Version=1; $Version<=$LatestVersion; $Version++ ) {
-		    my $vkeys = $result{"$Version:keys:$Prob"};
-		    my @keys = split(/\:/,$vkeys);		
-  
-		    foreach my $Key (@keys) {		  
-			if (($Key=~/\.(\w+)\.solved$/) && ($Key!~/^\d+\:/)) {
-			    my $Part = $1;
-			    $Tries = $result{"$Version:$Prob:resource.$Part.tries"};
-			    $ParCr = $result{"$Version:$Prob:resource.$Part.awarded"};
-			    my $Time = $result{"$Version:$Prob:timestamp"};
-			    $TempHash{"$Part.Time"} = ($Time) ? $Time : 0;
-			    $TempHash{"$Part.Tries"} = ($Tries) ? $Tries : 0;
-			    $TempHash{"$Part.ParCr"} = ($ParCr) ? $ParCr : 0;        
-			    $TotalTries += $TempHash{"$Part.Tries"};
-			    $TotParCr += $TempHash{"$Part.ParCr"};
-			    my $Val = $result{"$Version:$Prob:resource.$Part.solved"};
-			    if ( $Val eq 'correct_by_student' )
-                               { $Wrongs = $Tries - 1; $Code = 'C'; } 
-			    elsif ( $Val eq 'correct_by_override' )
-                               { $Wrongs = $Tries - 1; $Code = 'O'; }                        
-			    elsif ( $Val eq 'incorrect_attempted' || 
-                                $Val eq 'incorrect_by_override' )
-		               { $Wrongs = $Tries; $Code = 'I'; }
-			    $TempHash{"$Part.Code"} = $Code;
-			    $TempHash{"$Part.Wrongs"} = $Wrongs;
-			}
-     		    }
-                } 
-		for ( my $n = 0; $n < $PartNo; $n++ ) {		  
-		    my $part = $TempHash{$n};
-		    my $Yes = 0;
-                    if ( $TempHash{$part.'.Code'} eq 'C' ||
-                         $TempHash{$part.'.Code'} eq 'O'  ) 
-		       {$ProbSolved++;$Yes=1;}		
-
- #		    my $ptr = "$hash{'title_'.$ResId}";
-		    my $ptr = $TempHash{$part.'.PrOrd'}.'&'.$ResId;
-
-		    if ( $PartNo > 1 ) {                
-			$ptr .= "*(part $part)";
-			$Dis .= '&';
-		    }
-		    my $Fac = ($TempHash{"$part.Tries"}) ? 
-                              ($TempHash{"$part.ParCr"}/$TempHash{"$part.Tries"}) : 0;
-		    my $DisF;
-		    if ( $Fac > 0 &&  $Fac < 1 ) { 
-			$DisF = sprintf( "%.4f", $Fac );
-		    }
-		    else {$DisF = $Fac;}
-#		    $DisF .= '+'.$TempHash{"$part.Time"};
-		    $TimeTot += $TempHash{"$part.Time"};
-		    $Dis .= $TempHash{$part.'.PrOrd'}.'='.$DisF.'+'.$Yes;
-		    $ptr .= "&$TempHash{$part.'.Tries'}".
-		            "&$TempHash{$part.'.Wrongs'}".
-                            "&$TempHash{$part.'.Code'}";
-		    push (@list, $ptr);
-		    $TotalOpend++;
-		    $ProbTot++;
-		}
-            }
-	    #else { 
-		#for(my $n=0; $n<$PartNo; $n++) {
-		#    push (@list, "$TempHash{'0'.'.PrOrd'}.':'.$ResId:0:0:U");
-		#    $ProbTot++; 
-		#}
-	    #}
-        }
-	if ( $TotalTries ) {
-	    my $DisFac = ( $TotalTries ) ? ($TotParCr/$TotalTries) : 0;
-	    my $DisFactor = sprintf( "%.4f", $DisFac );
-	    $DiscFac{$DisFactor}=$Dis;
-	    #my $time;
-	    #if ($ProbSolved){
-		#$time = int(($TimeTot/$ProbSolved)-10000000);
-	    #}
-	    #$DiscFac{($DisFactor.':'.$sname.':'.$ProbTot.':'.$TotalOpend.':'.
-            #          $TotalTries.':'.$ProbSolved.':'.$time)}=$Dis;
-	}
+Returns a list of the selected students
+
+=cut
+
+#######################################################
+#######################################################
+sub get_students {
+    if (! @Students) {
+        &PrepareClasslist()
     }
-    #$r->print($sname.' PrCr= '.$TotParCr.' Slvd= '.$ProbSolved.' Tries='.$TotalTries.'<br>');
+    return @Students;
 }
 
+#######################################################
+#######################################################
 
-# ------------------------------------------------------------ Build page table
-sub tracetable {
-    my ($rid,$beenhere)=@_;
-    my $IsMap=0;
-    $rid=~/(\d+)\.(\d+)/;
-    $maps{&Apache::lonnet::declutter($hash{'map_id_'.$1})}='';#$hash{'title_'.$rid}; 
-    #$maps{$HWN}=$hash{'title_'.$rid}; 
-    unless ($beenhere=~/\&$rid\&/) {
-       $beenhere.=$rid.'&'; 
-       if (defined($hash{'is_map_'.$rid})) {
-	   my $cmap=$hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$rid}}};
-           if ( $cmap eq 'sequence' || $cmap eq 'page' ) { 
-               $cols[$#cols+1]=0;
-	       $P_Order++;
-	       $HWN=$P_Order;
-               $mapsort{$HWN} = $rid.':';
-	       $IsMap=1;
- 
-               #$maps{&Apache::lonnet::declutter($hash{'src_'.$rid})}= 
-               #      $hash{'title_'.$rid}; 
-           }
-           if ((defined($hash{'map_start_'.$hash{'src_'.$rid}})) &&
-               (defined($hash{'map_finish_'.$hash{'src_'.$rid}}))) {
-	       my $frid=$hash{'map_finish_'.$hash{'src_'.$rid}};
-
-               &tracetable($hash{'map_start_'.$hash{'src_'.$rid}},
-			   '&'.$frid.'&');
-
-	       $cols[$#cols+1]=($P_Order+1).':'.$frid;
-      
-	       my $meta=$hash{'src_'.$frid};
-	       my $PartNo = 0;
-	       if ($IsMap==0){
-               if ($meta) {
-		   if ($meta=~/\.(problem|exam|quiz|assess|survey|form)$/) {
-		       foreach (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))) {
-			   if ($_=~/^stores\_(\w+)\_tries$/) {
-			       &Apache::lonnet::metadata($meta,$_.'.part');
-			       $P_Order++;
-			       $mapsort{$HWN} .= '&'.$P_Order;
-			       $PartNo++;
-			       #$r->print('<br>'.$PartNo.'---'.$P_Order);
-			   }
-		       }
-		       foreach (split(/\,/,&Apache::lonnet::metadata($meta,'packages'))) {
-			   if ($_=~/^optionresponse\_(\w+)\_(\w+)$/) {
-#			       $r->print('<br>'.$_.&Apache::lonnet::metadata($meta,$_));
-			       $r->print('<br>'.$_.'...'.$P_Order);
-			       $OpResp{$P_Order+1}=$frid;
-			   } 
-		       }
-		   }
-               }
-	   }
-	   }
-       } else {
-	   $cols[$#cols+1]=($P_Order+1).':'.$rid;
-	   my $meta=$hash{'src_'.$rid};
-	   my $PartNo = 0;
-	   if ($meta) {
-	       if ($meta=~/\.(problem|exam|quiz|assess|survey|form)$/) {
-		   foreach my $Key(split(/\,/,&Apache::lonnet::metadata($meta,'keys'))) {
-		       if ($Key=~/^stores\_(\w+)\_tries$/) {
-			   my $Part=&Apache::lonnet::metadata($meta,$Key.'.part');
-			   $P_Order++;
-			   $mapsort{$HWN} .= '&'.$P_Order;
-			   $PartNo++;
-			   foreach (split(/\,/,&Apache::lonnet::metadata($meta,'packages'))) {
-			       if ($_=~/^optionresponse\_($Part)\_(\w+)$/) {
-				   #$r->print('<br>'.$_.'...'.$P_Order.'---'.$Part);
-				   $OpResp{$P_Order+1}=$rid;
-			       } 
-		   
-			   }
-
-		       }
-		   }
-	       }
-	   }       
-       }
-       if (defined($hash{'to_'.$rid})) {
-          foreach (split(/\,/,$hash{'to_'.$rid})){
-              &tracetable($hash{'goesto_'.$_},$beenhere);
-          }
-       }
-    }
+=pod
+
+=item &current_student()
+
+Returns a pointer to a hash containing data about the currently
+selected student.
+
+=cut
+
+#######################################################
+#######################################################
+sub current_student { 
+    return $curr_student;
 }
 
-sub MySort {          
-    if ( $Pos > 0 ) {
-	if ($ENV{'form.order'} eq 'Descending') {$b <=> $a;}
-	else { $a <=> $b; }
-    }
-    else {
-	if ($ENV{'form.order'} eq 'Descending') {$b cmp $a;}
-	else { $a cmp $b; }
-    }
+#######################################################
+#######################################################
+
+=pod
+
+=item &previous_student()
+
+Returns a pointer to a hash containing data about the student prior
+in the list of students.  Or something.  
+
+=cut
+
+#######################################################
+#######################################################
+sub previous_student { 
+    return $prev_student;
 }
 
-sub Build_Statistics {
-    $r->print(<<ENDPOP);
-    <script>
-    popwin=open('','popwin','width=400,height=100');
-    popwin.document.writeln('<html><body bgcolor="#88DDFF">'+
-      '<title>LON-CAPA Statistics</title>'+
-      '<h4>Computation Progress</h4>'+
-      '<form name=popremain>'+
-      '<input type=text size=35 name=remaining value=Starting></form>'+
-      '</body></html>');
-    popwin.document.close();
-    </script>
-ENDPOP
+#######################################################
+#######################################################
 
-    $r->rflush();
-# ---------------------------- Gathering the Data of students' tries
-    my $index;
-    for ($index=0;$index<=$#students;$index++) {
-#----------- update progress
-        $r->print('<script>popwin.document.popremain.remaining.value="'.
-                  'Computing '.($index+1).'/'.($#students+1).': '.
-                  $students[$index].'";</script>');
-        $r->rflush();
+=pod
 
-        &ExtractStudentData($students[$index],$cid);
-    }
+=item &next_student()
 
-# -------------------- sorting the Data
-    $r->print('<script>popwin.document.popremain.remaining.value="'.
-              'Calculating Discrimination Factors...";</script>');
-
-    @list = sort (@list);
-
-
-    &Discriminant();
-
-    $OpSel2='';
-    $OpSel1='selected';
- 		   
-    $p_count = 0; 
-    my $nIdx = 0;
-    my $dummy; 
-    my $p_val;
-    my $ResId;
-    my $NoElements = $#list + 1;
-#-------------------------------- loop for data representation
-    foreach (sort keys %mapsort) {
-	my ($Hid,$pr)=split(/\:/,$mapsort{$_});
-	my @lpr=split(/\&/,$pr);
-	&CreateTable(1,$Hid);
-	for (my $i=1; $i<=$#lpr; $i++) {
-	    my %storestats=();
-	    my ($PrOrd,$Prob,$Tries,$Wrongs,$Code)=split(/\&/,$list[$nIdx]);
-	    my $Temp = $Prob;
-	    my $MxTries = 0;
-	    my $TotalTries = 0;
-	    my $YES = 0;
-	    my $Incorrect = 0;
-	    my $Override = 0;
-	    my $StdNo = 0;
-	    my @StdLst;
-	    while ( $PrOrd == $lpr[$i] ) 
-	    {
-		$nIdx++;
-		$StdNo++;
-		$StdLst[ $StdNo ] = $Tries;
-		$TotalTries += $Tries;
-		if ( $MxTries < $Tries ) { $MxTries = $Tries; } 
-		if ( $Code eq 'C' ){ $YES++; }
-		elsif( $Code eq 'I' ) { $Incorrect++; }
-		elsif( $Code eq 'O' ) { $Override++; }
-		elsif( $Code eq 'U' ) { $StdNo--; }
-		($PrOrd,$Prob,$Tries,$Wrongs,$Code)=split(/\&/,$list[$nIdx]);
-	    }	
-
-	    $p_count++;
-	    my $Dummy;
-	    ($ResId,$Dummy)=split(/\*/,$Temp);
+Returns a pointer to a hash containing data about the next student
+to be viewed.
 
-	    $Temp = '<a href="'.$hash{'src_'.$ResId}.
-                '" target="_blank">'.$hash{'title_'.$ResId}.$Dummy.'</a>';
-    
-	    my $res = &Apache::lonnet::declutter($hash{'src_'.$ResId});
-	    my $urlres=$res;
+=cut
 
-	    $ResId=~/(\d+)\.(\d+)/;
-	    my $Map = &Apache::lonnet::declutter( $hash{'map_id_'.$1} );
-	    $urlres=$Map;
- 
-	    $res = '<a href="'.$hash{'src_'.$ResId}.'">'.$res.'</a>';
-	    #$Map = '<a href="'.$Map.'">'.$res.'</a>';
-
-#------------------------ Compute the Average of Tries about one problem
-	    my $Average = ($StdNo) ? $TotalTries/$StdNo : 0;
-
-	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___timestamp'}=time;       
-	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___stdno'}=$StdNo;
-	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___avetries'}=$Average;
-   
-#-------------------------------- Compute percentage of Wrong tries
-	    my $Wrong = ( $StdNo ) ? 100 * ( $Incorrect / $StdNo ) : 0;
-
-#-------------------------------- Compute Standard Deviation
-	    my $StdDev = 0; 
-	    if ( $StdNo > 1 ) {
-		for ( my $n = 0; $n < $StdNo; $n++ ) {
-		    my $Dif = $StdLst[ $n ]-$Average;
-		    $StdDev += $Dif*$Dif;
-		} 
-		$StdDev /= ( $StdNo - 1 );
-		$StdDev = sqrt( $StdDev );
-	    }
-
-#-------------------------------- Compute Degree of Difficulty
-	    my $DoDiff = 0;
-	    if( $TotalTries > 0 ) {
-		$DoDiff = 1 - ( ( $YES + $Override ) / $TotalTries );
-#	    $DoDiff =  ($TotalTries)/($YES + $Override+ 0.1);	    
-	    }
-       
-	    $storestats{$ENV{'request.course.id'}.'___'.$urlres.'___difficulty'}=$DoDiff;
-
-#-------------------------------- Compute the Skewness
-	    my $Skewness = 0;
-	    my $Sum = 0; 
-	    if ( $StdNo > 0 && $StdDev > 0 ) {
-		for ( my $n = 0; $n < $StdNo; $n++ ) {
-		    my $Dif = $StdLst[ $n ]-$Average;
-		    $Skewness += $Dif*$Dif*$Dif;
-		} 
-		$Skewness /= $StdNo;
-	    $Skewness /= $StdDev*$StdDev*$StdDev;
-	    }
-
-#--------------------- Compute the Discrimination Factors
-	    my ($Up1,$Up2)=split(/\:/,$DisUp{$lpr[$i]});
-	    my ($Lw1,$Lw2)=split(/\:/,$DisLow{$lpr[$i]});
-	    my $Dis1 = $Up1 - $Lw1;
-	    my $Dis2 = $Up2 - $Lw2;
-	    my $_D1 = sprintf("%.2f", $Dis1);
-	    my $_D2 = sprintf("%.2f", $Dis2);
-
-#-----------------  Some restition in presenting the float numbers
-	    my $Avg = sprintf( "%.2f", $Average );
-	    my $Wrng = sprintf( "%.1f", $Wrong );
-	    my $SD = sprintf( "%.1f", $StdDev );
-	    my $DoD = sprintf( "%.2f", $DoDiff );
-	    my $Sk = sprintf( "%.1f", $Skewness );
-	    my $join = $PrOrd.'&'.$Temp.'&'.$StdNo.'&'.
-                       $TotalTries.'&'.$MxTries.'&'.$Avg.'&'.
-                       $YES.'&'.$Override.'&'.$Wrng.'&'.$DoD.'&'.
-		       $SD.'&'.$Sk.'&'.$_D1.'&'.$_D2.'&'.$Prob;
-	    $CachData{($p_count-1)}=$join;
-
-	    $urlres=~/^(\w+)\/(\w+)/;
-	    if ($StdNo) { 
-		&Apache::lonnet::put('resevaldata',\%storestats,$1,$2); 
-	    }
-#-------------------------------- Row of statistical table
-	    if ( $DiscFlag == 0 ) {
-		&TableRow($join,$i,($p_count-1));
-	    } 
-	}
-	&CloseTable();
-    }
-#--------------------- close Progress Line
-    $r->print('<script>popwin.close()</script>');
-    $r->rflush(); 
+#######################################################
+#######################################################
+sub next_student { 
+    return $next_student;
 }
 
-sub Cache_Statistics {
-    my @list = ();
-    my $Useful;
-    my $UnUseful;
-    my %myHeader = reverse( %Header );
-    $Pos = $myHeader{$ENV{'form.sort'}};
-    if ($Pos > 0) {$Pos++;}
-    $p_count = 0;
-    foreach my $key( keys %CachData) { 
-	my @Temp=split(/\&/,$CachData{$key});
-	if ( $Pos == 0 ) {
-	    ($UnUseful,$Useful)=split(/\>/,$Temp[$Pos]);
-	}
-	else {
-	    $Useful = $Temp[$Pos];
-	}   
-	$list[$p_count]=$Useful.'@'.$CachData{$key};
-        $p_count++;
-    }
-
-    @list = sort MySort (@list);
-
-    my $nIdx=0;
-
-    if ( $Pos == 0 ) {
-	foreach (sort keys %mapsort) {
-	    my ($Hid,$pr)=split(/\:/,$mapsort{$_});
-	    &CreateTable(1,$Hid);
-	    my @lpr=split(/\&/,$pr);
-	    for (my $i=1; $i<=$#lpr; $i++) {
-		my($Pre, $Post) = split(/\@/,$list[$nIdx]); 
-		#$r->print('<br>'.$Pre.'---'.$Post);
-		&TableRow($Post,$i,$nIdx);
-		$nIdx++;
-	    }
-	    &CloseTable();
-	}
-    }
-    else {
-	&CreateTable(0);
-	for ( my $nIdx = 0; $nIdx < $p_count; $nIdx++ ) {
-	    my($Pre, $Post) = split(/\@/,$list[$nIdx]); 
-	    &TableRow($Post,$nIdx,$nIdx);
-	} 
-	&CloseTable();
+##############################################
+##############################################
+
+=pod 
+
+=item &StudentDataSelect($elementname,$status,$numvisible,$selected)
+
+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)
+
+=over 4
+
+=item $elementname The name of the HTML form element
+
+=item $status 'multiple' or 'single' selection box
+
+=item $numvisible The number of options to be visible
+
+=back
+
+=cut
+
+##############################################
+##############################################
+sub StudentDataSelect {
+    my ($elementname,$status,$numvisible)=@_;
+    if ($numvisible < 1) {
+        return;
     }
+    #
+    # Build the form element
+    my $Str = "\n";
+    $Str .= '<select name="'.$elementname.'" ';
+    if ($status ne 'single') {
+        $Str .= 'multiple="true" ';
+    }
+    $Str .= 'size="'.$numvisible.'" >'."\n";
+    #
+    # Deal with 'all'
+    $Str .= '    <option value="all" ';
+    foreach (@SelectedStudentData) {
+        if ($_ eq 'all') {
+            $Str .= 'selected ';
+            last;
+        }
+    }
+    $Str .= ">all</option>\n";
+    #
+    # Loop through the student data fields
+    foreach my $item (@StudentDataOrder) {
+        $Str .= '    <option value="'.$item.'" ';
+        foreach (@SelectedStudentData) {
+            if ($item eq $_ ) {
+                $Str .= 'selected ';
+                last;
+            }
+        }
+        $Str .= '>'.$item."</option>\n";
+    }
+    $Str .= "</select>\n";
+    return $Str;
 }
 
-sub TableRow {
-    my ($Str,$Idx,$RealIdx)=@_;
-    my($PrOrd,$Temp,$StdNo,$TotalTries,$MxTries,$Avg,$YES,$Override,
-       $Wrng,$DoD,$SD,$Sk,$_D1,$_D2,$Prob)=split(/\&/,$Str);	
-    my $Ptr =  "\n".'<tr>'.
-               "\n".'<td>'.($RealIdx+1).'</td>'.
-#               "\n".'<td>'.$PrOrd.$Temp.'</td>'.
-               "\n".'<td>'.$Temp.'</td>'.
-               "\n".'<td bgcolor="#EEFFCC"> '.$StdNo.'</td>'.
-               "\n".'<td bgcolor="#EEFFCC">'.$TotalTries.'</td>'.
-               "\n".'<td bgcolor="#EEFFCC">'.$MxTries.'</td>'.
-               "\n".'<td bgcolor="#DDFFFF">'.$Avg.'</td>'.
-               "\n".'<td bgcolor="#DDFFFF"> '.$YES.'</td>'.
-               "\n".'<td bgcolor="#DDFFFF"> '.$Override.'</td>'.
-               "\n".'<td bgcolor="#FFDDDD"> '.$Wrng.'</td>'.
-               "\n".'<td bgcolor="#FFDDDD">'.$DoD.'</td>'.
-               "\n".'<td bgcolor="#DDFFDD"> '.$SD.'</td>'.
-               "\n".'<td bgcolor="#DDFFDD"> '.$Sk.'</td>'.
-               "\n".'<td bgcolor="#FFDDFF"> '.$_D1.'</td>'.
-	       "\n".'<td bgcolor="#FFDDFF"> '.$_D2.'</td>';
-#    if( $OpResp{$PrOrd} ) {
-#	$Ptr.='<td>'.'<input type="submit" name="OpResp" value="'."View_$PrOrd".'" />'.'</td>';
-#    }   
-#    else {
-#	$Ptr.='<td> -------- </td>';
-#    }
-    $r->print("\n".$Ptr.'</tr>' );
-    $GraphDat{$RealIdx}=$DoD.':'.$Wrng;
-}
+#######################################################
+#######################################################
+
+=pod
+
+=item &get_selected_maps($elementname)
+
+Input: Name of the <select> form element used to specify the maps.
+
+Returns: Array of symbs of selected maps or the description 'all'.
+   If form.$elementname does not exist, 'all' is returned.
 
-# ------------------------------------------- Prepare data for Graphical chart
+=cut
 
-sub GetGraphData {
-    my $Tag = shift;
-    my $Col;
-    my $data='';
-    my $count = 0;
-    my $Max = 0;
-    my $cid=$ENV{'request.course.id'};
-    my $GraphDB = "/home/httpd/perl/tmp/$ENV{'user.name'}".
-                  "_$ENV{'user.domain'}_$cid\_graph.db";
-    foreach (keys %GraphDat) {delete $GraphDat{$_};}
-    if (-e "$GraphDB") {
-	if (tie(%GraphDat,'GDBM_File',"$GraphDB",&GDBM_READER,0640)) {
-	    if ( $Tag eq 'DoDiff Graph' ) {
-		$Tag = 'Degree-of-Difficulty';
-		$Col = 0;
-	    }
-	    else {
-		$Tag = 'Wrong-Percentage';
-		$Col = 1;
-	    }
-	    foreach (sort NumericSort keys %GraphDat) { 
-		my @Temp=split(/\:/,$GraphDat{$_});
-                my $inf = $Temp[$Col]; 
-		if ( $Max < $inf ) {$Max = $inf;}
-		$data .= $inf.',';
-		$count++;
-	    }
-            untie(%GraphDat);
-	    my $Course = $ENV{'course.'.$cid.'.description'};
-	    $Course =~ s/\ /"_"/eg;
-	    $GData=$Course.'&'.$Tag.'&'.$Max.'&'.$count.'&'.$data;
-
-	}
-	else {
-	    $r->print("Unable to tie hash to db file");
-	}
+#######################################################
+#######################################################
+sub get_selected_maps {
+    my ($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;
 }
 
 
-sub initial {
-# --------------------------------- Initialize the global varaibles
-  undef @students;
-  undef @cols;
-  undef %maps;
-  undef %section;
-  undef %StuBox;
-  undef @list;
-  undef %CachData;
-  undef %GraphDat;
-  undef %DiscFac;
-  undef %OpResp;
-  undef $CurMap;
-  undef $CurSec;
-  undef $CurStu;
-  undef $p_count;
-  undef $Pos;
-  undef $GData;
-  $DiscFlag=0; 
-  $P_Order=100000;
-  $HWN=$P_Order;
-}
+#######################################################
+#######################################################
 
+=pod
 
-sub ClassList {
+=item &selected_sequences_with_assessments
 
-    &GetStatus();
+Retrieve the sequences which were selected by the user to show.  
 
-    $cid=$ENV{'request.course.id'};
-    my $chome=$ENV{'course.'.$cid.'.home'};
-    my ($cdom,$cnum)=split(/\_/,$cid);
-# ----------------------- Get first and last resource, see if there is anything
-    $firstres=$hash{'map_start_/res/'.$ENV{'request.course.uri'}};
-    $lastres=$hash{'map_finish_/res/'.$ENV{'request.course.uri'}};
-    if (($firstres) && ($lastres)) {
-# ----------------------------------------------------------------- Render page
-	my $classlst=&Apache::lonnet::reply
-                 ('dump:'.$cdom.':'.$cnum.':classlist',$chome);
-	my $StudNo = 0;
-	my $now=time;
-	unless ($classlst=~/^error\:/) {
-	    foreach (sort split(/\&/,$classlst)) {
-		my ($name,$value)=split(/\=/,$_);
-		my ($end,$start)=split(/\:/,&Apache::lonnet::unescape($value));
-		$name=&Apache::lonnet::unescape($name);
-		my ($sname,$sdom)=split(/\:/,$name);
-		my $active=1;
-		my $Status=$ENV{'form.status'};
-		$Status = ($Status) ? $Status : 'Active';
-		if ( ( ($end) && $now > $end ) && 
-                     ( ($Status eq 'Active') ) ) { $active=0; }
-		if ( ($Status eq 'Expired') && 
-                     ($end == 0 || $now < $end) ) { $active=0; }
-		if ($active) {
-		    my $thisindex=$#students+1;
-		    $name=&Apache::lonnet::unescape($name);
-		    $students[$thisindex]=$name;
-		    my ($sname,$sdom)=split(/\:/,$name);
-		    #my %reply=&Apache::lonnet::idrget($sdom,$sname);
-		    #my $reply=&Apache::lonnet::reply('get:'.$sdom.':'.$sname.
-		    #         ':environment:lastname&generation&firstname&middlename',
-		    #         &Apache::lonnet::homeserver($sname,$sdom));
-		    my $ssec=&usection($sdom,$sname,$cid,$Status);
-		    if ($ssec==-1) {next;}
-		    $ssec=($ssec) ? $ssec : '(none)';
-		    #$ssec=(int($ssec)) ? int($ssec) : $ssec;
-		    $section{$ssec}=$ssec;
-		    if ($CurSec eq 'All Sections' || $ssec eq $CurSec) {
-			$students[$StudNo]=$name;
-			$StuBox{$sname}=$sdom;
-		    }
-		    $StudNo++;
-	        }
-	    }
-	}
-	else {
-	    $r->print('<h1>Could not access course data</h1>');
-	} 
-        $r->print("Total number of students : ".($#students+1));
-        $r->rflush();
-# --------------- Find all assessments and put them into some linear-like order
-	&tracetable($firstres,'&'.$lastres.'&');
-#    my $c=0;
-#    foreach (sort keys %mapsort) {
-#	$r->print('<br>'.$c.')'.$_.' ... '.$mapsort{$_});
-#	$c++;
-#    }
+Input: $mode: scalar.  Either 'selected' or 'all'.  If not specified,
+    'selected' is used.
+
+Returns: an array containing a navmap object and navmap resources, 
+    or an array containing a scalar with an error message.
+
+=cut
+
+#######################################################
+#######################################################
+sub selected_sequences_with_assessments {
+    my ($mode) = @_;
+    $mode = 'selected' if (! defined($mode));
+    my $navmap = Apache::lonnavmaps::navmap->new();
+    if (!defined($navmap)) {
+        return ('Can not open Coursemap');
+    }
+    #
+    my @sequences = $navmap->retrieveResources(undef,
+                                               sub { shift->is_map(); },1,0,1);
+    my @sequences_with_assessments;
+    for my $sequence ($navmap->getById('0.0'), @sequences) {
+	if ($navmap->hasResource($sequence,sub { shift->is_problem(); },0,1)){
+            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
+                }
+            }
+        }
 
-# ------------------------------------------------------------- End render page 
-    else {
-	$r->print('<h3>Undefined course sequence</h3>');
     }
-    &MapSecOptions();
+    return $navmap,@sequences_to_show;
 }
 
+##############################################
+##############################################
 
-sub Menu {
-    my $InpStr = $ENV{'form.sort'};
-    if ( $InpStr eq 'DoDiff Graph' || $InpStr eq '%Wrong Graph' ) {      
-	&GetGraphData($InpStr);
-    	$r->print('<IMG src="/cgi-bin/graph.gif?'.$GData.'" />');
-    }
-    else {
-	$r->print('<html><head><title>LON-CAPA Statistics</title></head>');
-
-
-        $r->print('<body bgcolor="#FFFFFF">'.
-                  '<script>window.focus(); window.width=500;window.height=500; </script>'.
-                  '<img align=right src=/adm/lonIcons/lonlogos.gif>');
-# ---------------------------------------------------------------- Course title
-        $r->print('<h1> Course : "'.
-                  $ENV{'course.'.$ENV{'request.course.id'}.
-                  '.description'}.'"</h1><h2>'.localtime().'</h2>');
-# ------------------------------- This is going to take a while, produce output
-        $r->rflush();	
-
-	$r->print("\n".'<form name=stat method=post action="/adm/statistics" >');
-
-	my $content = $ENV{'form.sort'};
-	if ($content eq '' || $content eq 'Return to Menu') {
-	    my $Ptr = '<h3>';
-	    $Ptr .= '<input type=submit name=sort value="Problem Evaluation"/>';
-	    $Ptr .= '<br><br>';
-	    $Ptr .= '<input type=submit name=sort value="Student Assessment"/>';
-	    $Ptr .= '</h3>';
-	    $r->print( $Ptr );
-      	}
-	else {
-	    &initial();
-	    &ClassList();
-	    if ( $content eq 'Student Assessment' || 
-                    $content eq 'Create Student Report' ) {
-		&StudentOptions();
-		&StudentReport($CurStu,$StuBox{"$CurStu"});
-	    }
-	    else {
-		&PreStatTable();
-	    }
-	}
-	$r->print("\n".'</form>'.
-                  "\n".'</body>'.
-                  "\n".'</html>');
-	$r->rflush();
+=pod 
+
+=item &map_select($elementname,$status,$numvisible,$restriction) 
+
+Returns html for a selection box allowing the user to choose one (or more) 
+of the sequences in the course.  The values of the sequences are the symbs.
+If the top sequence is selected, the value 'top' will result.
+
+=over 4
+
+=item $elementname The name of the HTML form element
+
+=item $status 'multiple' or 'single' selection box
+
+=item $numvisible The number of options to be visible
+
+=back
+
+=cut
+
+##############################################
+##############################################
+sub map_select {
+    my ($elementname,$status,$numvisible)=@_;
+    if ($numvisible < 1) {
+        return;
+    }
+    #
+    # Set up array of selected items
+    my @selected_maps = &get_selected_maps($elementname);
+    #
+    # Build the form element
+    my $form = "\n";
+    $form .= '<select name="'.$elementname.'" ';
+    if ($status ne 'single') {
+        $form .= 'multiple="true" ';
+    }
+    $form .= 'size="'.$numvisible.'" >'."\n";
+    #
+    # Put in option for 'all'
+    $form .= '    <option value="all" ';
+    if ($selected_maps[0] eq 'all') {
+        $form .= 'selected ';
+    }
+    $form .= ">all</option>\n";
+    #
+    # Loop through the sequences
+    my @sequences = &selected_sequences_with_assessments('all');
+    my $navmap;
+    if (!ref($sequences[0])) {
+        return $sequences[0];
+    } else {
+        $navmap = shift(@sequences);
+    }
+    foreach my $seq (@sequences){
+        $form .= '    <option value="'.$seq->symb.'" ';
+        foreach (@selected_maps) {
+            if ($seq->symb eq $_) {
+                $form .= 'selected ';
+                last;
+            }
+        }
+        $form .= '>'.$seq->compTitle."</option>\n";
     }
+    $form .= "</select>\n";
+    return $form;
 }
 
-sub StudentOptions {
-    my $OpSel5='';
-    $CurStu = $ENV{'form.student'};
-    if ( $CurStu eq '' ) { 
-        $CurStu = 'All Students';
-        $OpSel5 = 'selected';
-    }
-    my $Ptr ='';
-# ----------------------------------- Loading the Students Combobox
-    $Ptr .= '<br><b>Select Student</b>'."\n".
-       	    '<select name="student">'."\n". 
-	    '<option '.$OpSel5.'>All Students</option>';                     	     	     
-    foreach my $key ( sort keys %StuBox ) {	          
-	$Ptr .= '<option';
-	if ($CurStu eq $key) {$Ptr .= ' selected';}     
-        $Ptr .= '>'.$key."</option>\n";	     
-    }
-    $Ptr .= '</select>';
-    $Ptr .= '<br><input type="submit" name="sort" value="Create Student Report" />';
-    $r->print( $Ptr );
-    $r->rflush();	
-}
+##############################################
+##############################################
+
+=pod 
 
-sub GetStatus {
-    $OpSel1='';
-    $OpSel2='';
-    $OpSel3='';
-    $OpSel4='';
-
-    if ( $ENV{'form.order'} eq 'Descending' ) { $OpSel2='selected'; }
-    else { $OpSel1 = 'selected'; }
-
-    my %myHeader = reverse( %Header );
-    $Pos = $myHeader{$ENV{'form.sort'}};
-    if ($Pos == 0) {
-	$OpSel1 = 'selected';
-	$ENV{'form.order'}='Ascendig';
-    }
-
-    $CurMap = $ENV{'form.maps'};
-    if ( $CurMap eq '' ) { 
-	$CurMap = 'All Maps';
-	$OpSel3 = 'selected';
-    }
-    $CurSec = $ENV{'form.section'};
-    if ( $CurSec eq '' ) { 
-	$CurSec = 'All Sections';
-        $OpSel4 = 'selected';
+=item &SectionSelect($elementname,$status,$numvisible) 
+
+Returns html for a selection box allowing the user to choose one (or more) 
+of the sections in the course.  
+
+Uses the package variables @Sections
+=over 4
+
+=item $elementname The name of the HTML form element
+
+=item $status 'multiple' or 'single' selection box
+
+=item $numvisible The number of options to be visible
+
+=back
+
+=cut
+
+##############################################
+##############################################
+sub SectionSelect {
+    my ($elementname,$status,$numvisible)=@_;
+    if ($numvisible < 1) {
+        return;
+    }
+    #
+    # Make sure we have the data we need to continue
+    if (! @Sections) {
+        &PrepareClasslist()
     }
+    #
+    # Build the form element
+    my $Str = "\n";
+    $Str .= '<select name="'.$elementname.'" ';
+    if ($status ne 'single') {
+        $Str .= 'multiple="true" ';
+    }
+    $Str .= 'size="'.$numvisible.'" >'."\n";
+    #
+    # Loop through the sequences
+    foreach my $s (@Sections) {
+        $Str .= '    <option value="'.$s.'" ';
+        foreach (&get_selected_sections()) {
+            if ($s eq $_) {
+                $Str .= 'selected ';
+                last;
+            }
+        }
+        $Str .= '>'.$s."</option>\n";
+    }
+    $Str .= "</select>\n";
+    return $Str;
 }
 
-
-sub MapSecOptions {
-# ----------------------------------- Loading the Maps Combobox
-    my $Ptr = '<br>';
-    $Ptr .= '<br><input type="submit" name="sort" value="Return to Menu" />';
-    $Ptr .= '<br><b> Select &nbsp; Map &nbsp; &nbsp; </b>'."\n".
-       	    '<select name="maps">'."\n". 
-	    '<option '.$OpSel3.'>All Maps</option>';                     	     	     
-    foreach my $key ( sort keys %maps ) {	          
-	$Ptr .= '<option';
-        if ($CurMap eq $key) {$Ptr .= ' selected';}	     
-	$Ptr .= '>'.$key."</option>\n";	     
-    }
-    $Ptr .= '</select>';
-    $Ptr .= '&nbsp;&nbsp;&nbsp;';
-
-# ----------------------------------- Loading the Sections Combobox
-    $Ptr .= '<br><b>Select Section</b>'."\n".
-       	    '<select name="section">'."\n". 
-	    '<option '.$OpSel4.'>All Sections</option>';                     	     	     
-    foreach my $key ( sort keys %section ) {	          
-	$Ptr .= '<option';
-        if ($CurSec eq $key) {$Ptr .= ' selected';}     
-	$Ptr .= '>'.$key."</option>"."\n";	     
+##################################################
+##################################################
+sub DisplayClasslist {
+    my ($r)=@_;
+    &Apache::lonhtmlcommon::add_breadcrumb
+        ({text=>'Select One Student'});
+    #
+    # Output some of the standard interface components
+    my $Str;
+    $Str .= &Apache::lonhtmlcommon::breadcrumbs(undef,'Select One Student');
+    $Str .= '<p><table cellspacing="5">'."\n";
+    $Str .= '<tr>';
+    $Str .= '<th align="center"><b>'.&mt('Sections').'</b></th>';
+    $Str .= '<th align="center"><b>'.&mt('Enrollment Status').'</b></th>';
+    $Str .= '</tr>'.$/;
+    $Str .= '<tr>';
+    $Str .= '<td>'.
+        &Apache::lonstatistics::SectionSelect('Section','multiple',5).
+        '</td>';
+    $Str .= '<td>'.
+        &Apache::lonhtmlcommon::StatusOptions(undef,undef,5).
+        '</td>';
+    
+    $Str .= '</tr>'.$/;
+    $Str .= '</table></p>';
+    $Str .= '<input type="submit" name="selectstudent" value="'.
+        &mt('Update Display').'" />';
+    $r->print($Str);
+    $r->rflush();
+    #
+    my @Fields = ('fullname','username','domain','id','section','status');
+    #
+    $Str = '';
+    my @selected_sections = &get_selected_sections();
+    if (! @Students) {
+        if ($selected_sections[0] eq 'all') { 
+            if (lc($env{'form.Status'}) eq 'any') {
+                $Str .= '<h2>'.
+                    &mt('There are no students in the course.').
+                    '</h2>';
+            } elsif (lc($env{'form.Status'}) eq 'active') {
+                $Str .= '<h2>'.
+                &mt('There are no currently enrolled students in the course.').
+                    '</h2>';
+            } elsif (lc($env{'form.Status'}) eq 'expired') {
+                $Str .= '<h2>'.
+                    &mt('There are no previously enrolled students in the course.').
+                        '</h2>';
+            }
+        } else { 
+            my $sections;
+            if (lc($env{'form.Status'}) eq 'any') {
+                $Str .= '<h2>'.
+                    &mt('There are no students in the selected sections.').
+                    '</h2>';
+            } elsif (lc($env{'form.Status'}) eq 'active') {
+                $Str .= '<h2>'.
+                    &mt('There are no currently enrolled students in the selected sections.').
+                    '</h2>';
+            } elsif (lc($env{'form.Status'}) eq 'expired') {
+                $Str .= '<h2>'.
+                    &mt('There are no previously enrolled students in the selected sections.').
+                    '</h2>';
+            }
+        }
+        $Str.= '<a href="/adm/statistics?reportSelected=student_assessment">'.
+            &mt('Click here to return to the chart').'</a>';
+        $r->print($Str);
+        $r->rflush();
+        return;
     }
-    $Ptr .= '</select>'."\n";
 
-    $r->print( $Ptr );
+    # "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) {
+        $Str .= '<th><a href="/adm/statistics?'.
+            'reportSelected=student_assessment&'.
+            'selectstudent=1&'.
+            'sort='.$field.'">'.&mt($field).
+            '</a></th>';
+    }
+    $Str .= '</tr>'."\n";
+    #
+    my $alternate = 0;
+    foreach my $student (@Students) { # @Students is a package variable
+        my $sname = $student->{'username'}.':'.$student->{'domain'};
+        if($alternate) {
+            $Str .= '<tr bgcolor="#ffffe6">';
+        } else {
+            $Str .= '<tr bgcolor="#ffffc6">';
+        }
+        $alternate = ($alternate + 1) % 2;
+        #
+        foreach my $field (@Fields) {
+            $Str .= '<td>';
+            if ($field eq 'fullname' || $field eq 'username') {
+                $Str .= '<a href="/adm/statistics?reportSelected=';
+                $Str .= &Apache::lonnet::escape('student_assessment');
+                $Str .= '&sort='.&Apache::lonnet::escape($env{'form.sort'});
+                $Str .= '&SelectedStudent=';
+                $Str .= &Apache::lonnet::escape($sname).'">';
+                $Str .= $student->{$field}.'&nbsp';
+                $Str .= '</a>';
+            } elsif ($field eq 'status') {
+                $Str .= &mt($student->{$field});
+            } else {
+                $Str .= $student->{$field};
+            }
+            $Str .= '</td>';
+        }
+        $Str .= "</tr>\n";
+    }
+    $Str .= '</table></td></tr></table>'."\n";
+    #
+    $r->print($Str);
     $r->rflush();
+    #
+    return;
 }
 
+##############################################
+##############################################
+sub CreateMainMenu {
+    #
+    # Define menu data
+    my @reports = ({ internal_name => 'problem_statistics',
+                     name => &mt('Overall Problem Statistics'),
+                     short_description => 
+    &mt('Student performance statistics on all problems.'),
+                 },
+                   { internal_name => 'problem_analysis',
+                     name => &mt('Detailed Problem Analysis'),
+                     short_description => 
+    &mt('Detailed statistics and graphs of student performance on problems.'),
+                 },
+                   { internal_name => 'submissiontime_analysis',
+                     name => &mt('Submission Time Plots'),
+                     short_description => 
+    &mt('Display and analysis of submission times on assessments.'),
+                 },
+                   { internal_name => 'student_submission_reports',
+                     name => &mt('Student Submission Reports'),
+                     short_description => 
+    &mt('Prepare reports of student submissions.'),
+                 },
+                   { internal_name => 'survey_reports',
+                     name => &mt('Survey Reports'),
+                     short_description => 
+    &mt('Prepare reports on survey results.'),
+                 },
+                   { internal_name => 'correct_problems_plot',
+                     name => &mt('Correct Problems Plot'),
+                     short_description => 
+    &mt('Display a histogram of student performance in the course.'),
+                 },
+#                   { internal_name => 'student_assessment',
+#                     name => &mt('Problem Status Chart'),
+#                     short_description => 
+#    &mt('Brief view of each students performance in course.'),
+#                 },
+                   # 'percentage'  => 'Correct-problems Plot',
+                   # 'activitylog' => 'Activity Log',
+                   );
+    #
+    # Create the menu
+    my $Str;
+    $Str .= '<h2>'.&mt('Please select a report to generate').'</h2>';
+    foreach my $reportdata (@reports) {
+        $Str .='    <h3><a href="/adm/statistics?reportSelected='.
+            $reportdata->{'internal_name'}.'" >'.
+            $reportdata->{'name'}."</a></h3>\n";
+        $Str .= '    '.('&nbsp;'x8).$reportdata->{'short_description'}.
+            "\n";
+    }
+    $Str .="</dl>\n";
+    #
+    return $Str;
+}
 
-# ================================================================ Main Handler
-
+##############################################
+##############################################
 sub handler {
-    $r=shift;
-
-    if (&Apache::lonnet::allowed('vgr',$ENV{'request.course.id'})) {
-# ------------------------------------------- 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');
-	    }
-	    $r->send_http_header;
-	    return OK;
-	}    
-	my $requrl=$r->uri;
-# ----------------------------------------------------------------- Tie db file
-
-	undef %hash;
-
-	if ($ENV{'request.course.fn'}) {
-	    my $fn=$ENV{'request.course.fn'};
-	    if (-e "$fn.db") {
-		if (tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER,0640)) {
-# ------------------------------------------------------------------- Hash tied
-		    $r->content_type('text/html');
-		    $r->send_http_header;
-		    &Menu();
-		}
-		else {
-		    $r->content_type('text/html');
-		    $r->send_http_header;
-		    $r->print('<html><body>Coursemap undefined.</body></html>');
-		}
-# ------------------------------------------------------------------ Untie hash
-		unless (untie(%hash)) {
-		    &Apache::lonnet::logthis("<font color=blue>WARNING: ".
-                            "Could not untie coursemap $fn (browse).</font>"); 
-		}
-
-# -------------------------------------------------------------------- All done
-		return OK;
-# ----------------------------------------------- Errors, hash could no be tied
-	    }
-	} 
-	else {
-	    $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
-	    return HTTP_NOT_ACCEPTABLE; 
-	}
-    }
-    else {
-        $ENV{'user.error.msg'}=
-        $r->uri.":vgr:0:0:Cannot view grades for complete course";
-
-        return HTTP_NOT_ACCEPTABLE; 
+    my $r=shift;
+    my $c = $r->connection();
+    #
+    # Check for overloading
+    my $loaderror=&Apache::lonnet::overloaderror($r);
+    if ($loaderror) { return $loaderror; }
+    $loaderror=
+       &Apache::lonnet::overloaderror($r,
+         $env{'course.'.$env{'request.course.id'}.'.home'});
+    if ($loaderror) { return $loaderror; }
+    #
+    # Check for access
+    if (! &Apache::lonnet::allowed('vgr',$env{'request.course.id'})) {
+        $env{'user.error.msg'}=
+            $r->uri.":vgr:0:0:Cannot view grades for complete course";
+        if (! &Apache::lonnet::allowed('vgr',
+                      $env{'request.course.id'}.'/'.$env{'request.course.sec'})) {
+            $env{'user.error.msg'}=
+                $r->uri.":vgr:0:0:Cannot view grades with given role";
+            return HTTP_NOT_ACCEPTABLE;
+        }
+    }
+    #
+    # Send the header
+    &Apache::loncommon::no_cache($r);
+    &Apache::loncommon::content_type($r,'text/html');
+    $r->send_http_header;
+    if ($r->header_only) { return OK; }
+    #
+    # Extract form elements from query string
+    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},
+                                            ['sort','reportSelected',
+                                             'SelectedStudent']);
+    #
+    # Give the LON-CAPA page header
+    my $style = <<ENDSTYLE;
+<style type="text/css">
+    ul.sub_studentans { list-style-type: none }
+    ul.sub_correctans { list-style-type: none }
+    tr.even           { background-color: \#CCCCCC }
+    td.essay          { border: 1px solid gray; }
+</style>
+ENDSTYLE
+    my $html=&Apache::lonxml::xmlbegin();
+    $r->print($html.'<head><title>'.
+              &mt('Course Statistics and Charts').
+              '</title>'.$style.
+              "</head>\n".
+              &Apache::loncommon::bodytag('Course Statistics and Charts'));
+    $r->rflush();
+    # 
+    # Either print out a menu for them or send them to a report
+    &Apache::lonhtmlcommon::clear_breadcrumbs();
+    &Apache::lonhtmlcommon::add_breadcrumb({href=>'/adm/statistics',
+                                            title=>'Statistics',
+                                            text =>'Statistics',
+                                            faq=>139,
+                                            bug=>'Statistics and Charts'});
+    if (! exists($env{'form.reportSelected'}) || 
+        $env{'form.reportSelected'} eq '') {
+        $r->print(&Apache::lonhtmlcommon::breadcrumbs
+                  (undef,&mt('Statistics Main Page')).
+                  &CreateMainMenu());
+    } else {
+    #
+        if (! &Apache::lonmysql::verify_sql_connection()) {
+            my $serveradmin = $r->dir_config('lonAdmEMail');
+            $r->print('<h2><font color="Red">'.
+                      &mt('Unable to connect to database!').
+                      '</font></h2>');
+            $r->print('<p>'.
+                      &mt('Please notify the server administrator ').
+                      '<b>'.$serveradmin.'</b></p>');
+            $r->print('<p>'.
+                      &mt('Course Statistics and Charts cannot be '.
+                          'retrieved until the database is restarted.  '.
+                          'Your data is intact but cannot be displayed '.
+                          'at this time.').'</p>');
+            $r->print('</body></html>');
+            return;
+        }
+        #
+        # Clean out the caches
+        if (exists($env{'form.ClearCache'})) {
+            &Apache::loncoursedata::delete_caches($env{'requres.course.id'});
+        }
+        #
+        # Begin form output
+        $r->print('<form name="Statistics" ');
+        $r->print('method="post" action="/adm/statistics">');
+        $r->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);
+        }
+        #
+        $r->print("</form>\n");
     }
+    $r->print("</body>\n</html>\n");
+    $r->rflush();
+    #
+    return OK;
 }
+
 1;
-__END__
 
+#######################################################
+#######################################################
 
+=pod
+
+=back
+
+=cut
+
+#######################################################
+#######################################################
+
+__END__