# The LearningOnline Network with CAPA
# (Publication Handler
#
# $Id: lonstatistics.pm,v 1.11 2002/03/17 01:30:00 minaeibi Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
# (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 Behrouz Minaei
###

package Apache::lonstatistics; 

use strict;
use Apache::Constants qw(:common :http);
use Apache::lonnet();
use Apache::lonhomework;
use HTML::TokeParser;
use GDBM_File;

# -------------------------------------------------------------- Module Globals
my %hash;
my %CachData;
my %GraphDat;
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");


sub get_student_answers {
  my ($symb,$username,$domain,$courseid) = @_;
  my ($map,$id,$feedurl) = split(/___/,$symb);
  my (%old,%moreenv);
  my @elements=('symb','courseid','domain','username');
  foreach my $element (@elements) {
    $old{$element}=$ENV{'form.grade_'.$element};
    $moreenv{'form.grade_'.$element}=eval '$'.$element #'
  }
  $moreenv{'form.grade_target'}='answer';
  &Apache::lonnet::appenv(%moreenv);
  my $userview=&Apache::lonnet::ssi('/res/'.$feedurl);
  &Apache::lonnet::delenv('form.grade_');
  foreach my $element (@elements) {
    $ENV{'form.grade_'.$element}=$old{$element};
  }
  $userview=~s/\<body[^\>]*\>//gi;
  $userview=~s/\<\/body\>//gi;
  $userview=~s/\<html\>//gi;
  $userview=~s/\<\/html\>//gi;
  $userview=~s/\<head\>//gi;
  $userview=~s/\<\/head\>//gi;
  $userview=~s/action\s*\=/would_be_action\=/gi;
  return $userview;
}



#------- 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;
}


#------- 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);
}

   
sub NumericSort {          
    $a <=> $b;
}

# ------ Create different Student Report 
sub StudentReport {

    my ($sname,$sdom)=@_;

    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 ($_=~/^stores\_(\d+)\_tries$/) {
                    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++;
		    }
		}
            }

            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'}";    
		}
            }
	    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";
    }
    $Result .= "\n".'</tr>'."\n";    
    $r->print( $Result );
    $r->rflush();
}

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 {
	    $r->print("Unable to tie hash to db file");
        }
    }
    #$r->print('Total instances of the problems : '.($p_count*($#students+1)));

    untie(%CachData);
    untie(%GraphDat);
}


# ------------------------------------- Find the section of student in a course

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;
        }
    }
    return '-1';
}


# ------ Dump the Student's DB file and handling the data for statistics table 

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 ($_=~/^stores\_(\d+)\_tries$/) {
                    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 $Prob = $Map.'___'.$PrbId.'___'.
                       &Apache::lonnet::declutter( $hash{'src_'.$ResId} );
            $Code='U';
            $Tries = 0;
	    $ParCr = 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"};
			    $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;
	}
    }
    #$r->print($sname.' PrCr= '.$TotParCr.' Slvd= '.$ProbSolved.' Tries='.$TotalTries.'<br>');
}


# ------------------------------------------------------------ Build page table
sub tracetable {
    my ($rid,$beenhere)=@_;
    $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} = $rid.':'; 
               #$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 $PartNo = 0;
               if ($meta) {
		   if ($meta=~/\.(problem|exam|quiz|assess|survey|form)$/) {
		       foreach (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))) {
			   if ($_=~/^stores\_(\d+)\_tries$/) {
			       &Apache::lonnet::metadata($meta,$_.'.part');
			       $P_Order++;
			       $mapsort{$HWN} .= '&'.$P_Order;
			       $PartNo++;
			       #$r->print('<br>'.$PartNo.'---'.$P_Order);
			   }
		       }
		   }
               }
	   }
       } 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 (split(/\,/,&Apache::lonnet::metadata($meta,'keys'))) {
		       if ($_=~/^stores\_(\d+)\_tries$/) {
			   &Apache::lonnet::metadata($meta,$_.'.part');
			   $P_Order++;
			   $mapsort{$HWN} .= '&'.$P_Order;
			   $PartNo++;
		       }
		   }
	       }
	   }
       }
       if (defined($hash{'to_'.$rid})) {
          foreach (split(/\,/,$hash{'to_'.$rid})){
              &tracetable($hash{'goesto_'.$_},$beenhere);
          }
       }
    }
}

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; }
    }
}

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();

        &ExtractStudentData($students[$index],$cid);
    }

# -------------------- 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);

	    $Temp = '<a href="'.$hash{'src_'.$ResId}.
                '" target="_blank">'.$hash{'title_'.$ResId}.$Dummy.'</a>';
    
	    my $res = &Apache::lonnet::declutter($hash{'src_'.$ResId});
	    my $urlres=$res;

	    $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 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[$nIdx]); 
		&TableRow($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();
    }
}

sub TableRow {
    my ($Str,$Idx,$RealIdx)=@_;
    my($PrOrd,$Temp,$StdNo,$TotalTries,$MxTries,$Avg,$YES,
       $Override,$Wrng,$DoD,$SD,$Sk,$_D1,$_D2,$Prob)=split(/\:/,$Str);	
    $r->print( "\n".'<tr>'.
               "\n".'<td>'.($RealIdx+1).'</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>'.
               "\n".'</tr>' );
    $GraphDat{$RealIdx}=$DoD.':'.$Wrng;
}

# ------------------------------------------- Prepare data for Graphical chart

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 initial {
# --------------------------------- Initialize the global varaibles
  undef @students;
  undef @cols;
  undef %maps;
  undef %section;
  undef %StuBox;
  undef @list;
  undef %CachData;
  undef %GraphDat;
  undef %DiscFac;
  undef $CurMap;
  undef $CurSec;
  undef $CurStu;
  undef $p_count;
  undef $Pos;
  undef $GData;
  $DiscFlag=0; 
  $P_Order=100000;
  $HWN=$P_Order;
}


sub ClassList {

    &GetStatus();

    $cid=$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++;
#    }
    }

# ------------------------------------------------------------- End render page 
    else {
	$r->print('<h3>Undefined course sequence</h3>');
    }
    &MapSecOptions();
}


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();
    }
}

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();	
}

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';
    }
}


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";	     
    }
    $Ptr .= '</select>'."\n";

    $r->print( $Ptr );
    $r->rflush();
}


# ================================================================ 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; 
    }
}
1;
__END__