--- loncom/interface/statistics/lonproblemanalysis.pm	2003/10/06 20:51:20	1.25
+++ loncom/interface/statistics/lonproblemanalysis.pm	2003/10/16 15:24:49	1.41
@@ -1,6 +1,7 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: lonproblemanalysis.pm,v 1.25 2003/10/06 20:51:20 matthew Exp $
+
+# $Id: lonproblemanalysis.pm,v 1.41 2003/10/16 15:24:49 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -34,223 +35,583 @@ use Apache::lonhtmlcommon();
 use Apache::loncoursedata();
 use Apache::lonstatistics;
 use Apache::lonlocal;
+use HTML::Entities();
+
+my $plotcolors = ['#33ff00', 
+                  '#0033cc', '#990000', '#aaaa66', '#663399', '#ff9933',
+                  '#66ccff', '#ff9999', '#cccc33', '#660000', '#33cc66',
+                  ]; 
 
 sub BuildProblemAnalysisPage {
     my ($r,$c)=@_;
     $r->print('<h2>'.&mt('Option Response Problem Analysis').'</h2>');
     $r->print(&CreateInterface());
-    if (exists($ENV{'form.problemchoice'})) {
-        $r->print('<hr />');
+    #
+    my @Students = @Apache::lonstatistics::Students;
+    #
+    if (exists($ENV{'form.ClearCache'}) || 
+        exists($ENV{'form.updatecaches'}) ||
+        (exists($ENV{'form.firstanalysis'}) &&
+         $ENV{'form.firstanalysis'} ne 'no')) {
         &Apache::lonstatistics::Gather_Full_Student_Data($r);
+    }
+    if (! exists($ENV{'form.firstanalysis'})) {
+        $r->print('<input type="hidden" name="firstanalysis" value="yes" />');
+    } else {
+        $r->print('<input type="hidden" name="firstanalysis" value="no" />');
+    }
+    $r->rflush();
+    if (exists($ENV{'form.problemchoice'}) && 
+        ! exists($ENV{'form.SelectAnother'})) {
+        $r->print('<input type="submit" name="ProblemAnalysis" value="'.
+                  &mt('Analyze Problem Again').'" />');
+        $r->print('&nbsp;'x5);
+        $r->print('<input type="submit" name="ClearCache" value="'.
+                  &mt('Clear Caches').'" />');
+        $r->print('&nbsp;'x5);
+        $r->print('<input type="submit" name="updatecaches" value="'.
+                  &mt('Update Student Data').'" />');
+        $r->print('&nbsp;'x5);
+        $r->print('<input type="hidden" name="problemchoice" value="'.
+                  $ENV{'form.problemchoice'}.'" />');
+        $r->print('<input type="submit" name="SelectAnother" value="'.
+                  &mt('Choose a different resource').'" />');
+        $r->print('&nbsp;'x5);
+        #
+        $r->print('<hr />');
         #
         my ($symb,$part,$resid) = &get_problem_symb(
                      &Apache::lonnet::unescape($ENV{'form.problemchoice'})
                                            );
-        $r->print('<hr />');
+        #
         my $resource = &get_resource_from_symb($symb);
         if (defined($resource)) {
+            $r->print('<h3>'.$resource->{'src'}.'</h3>');
             my %Data = &get_problem_data($resource->{'src'});
             my $ORdata = $Data{$part.'.'.$resid};
             ##
-            ## Render the problem for display
+            ## Render the problem
             my $base;
             ($base,undef) = ($resource->{'src'} =~ m|(.*/)[^/]*$|);
             $base = "http://".$ENV{'SERVER_NAME'}.$base;
-            $r->print('</form>'.
-                      '<table bgcolor="ffffff"><tr><td>'.
+            my $rendered_problem = 
+                &Apache::lonnet::ssi_body($resource->{'src'});
+            $rendered_problem =~ s/<\s*form\s*/<nop /g;
+            $rendered_problem =~ s|(<\s*/form\s*>)|<\/nop>|g;
+            $r->print('<table bgcolor="ffffff"><tr><td>'.
                       '<base href="'.$base.'" />'.
-#                      &Apache::loncommon::get_student_view
-#                      ($symb,$ENV{'user.name'},$ENV{'user.domain'},$ENV{'request.course.id'},'web').
-                      &Apache::lonnet::ssi_body($resource->{'src'}).
-                      '</td></tr></table>'.
-           '<form name="Statistics" method="post" action="/adm/statistics">');
+                      $rendered_problem.
+                      '</td></tr></table>');
             ##
             ## Analyze the problem
-            my @Data = &Apache::loncoursedata::get_optionresponse_data
-                (undef,$symb,$resid);
-            my $analysis_html = &DoTriesAnalysis(\@Data,$ORdata);
-            $r->print($analysis_html);
+            my $PerformanceData = 
+                &Apache::loncoursedata::get_optionresponse_data
+                                           (\@Students,$symb,$resid);
+            if (defined($PerformanceData) && 
+                ref($PerformanceData) eq 'ARRAY') {
+                if ($ENV{'form.AnalyzeOver'} eq 'Tries') {
+                    my $analysis_html = &tries_analysis($PerformanceData,
+                                                         $ORdata);
+                    $r->print($analysis_html);
+                } elsif ($ENV{'form.AnalyzeOver'} eq 'Time') {
+                    my $analysis_html = &time_analysis($PerformanceData,
+                                                         $ORdata);
+                $r->print($analysis_html);
+                } else {
+                    $r->print('<h2>'.
+                              &mt('The analysis you have selected is '.
+                                         'not supported at this time').
+                              '</h2>');
+                }
+            } else {
+                $r->print('<h2>'.
+                          &mt('There is no student data for this problem.').
+                          '</h2>');
+            }
         } else {
             $r->print('resource is undefined');
         }
-        $r->print('<ol>');
-        $r->print("<li /><strike>render problem</strike>\n");
-        $r->print("<li /><strike>Get student response data</strike>\n");
-        $r->print("<li />image tag for plot\n");
-        $r->print("<li />plot key\n");
-        $r->print('</ol>');
         $r->print('<hr />');
     } else {
-        $r->print('<h3>No Problem Selected</h3>');
+        $r->print('<input type="submit" name="ProblemAnalysis" value="'.
+                  &mt('Analyze Problem').'" />');
+        $r->print('&nbsp;'x5);
+        $r->print('<h3>'.&mt('Please select a problem to analyze').'</h3>');
+        $r->print(&OptionResponseProblemSelector());
     }
-    # Okay, they asked for data, so make sure we get the latest data.
-    $r->print(&OptionResponseProblemSelector());
 }
 
 
-sub DoTriesAnalysis {
-    my ($Data,$ORdata) = @_;
-    my $mintries = 1;
-    my $maxtries = 3;
-    my %ResponseData = &analyze_option_data_by_tries($Data,
-                                                 $mintries,$maxtries);
-    my @Foils = sort(keys(%ResponseData));
-    my %Row_Label;
+#########################################################
+#########################################################
+##
+##      Misc interface routines use by analysis code
+##
+#########################################################
+#########################################################
+sub build_foil_index {
+    my ($ORdata) = @_;
+    return if (! exists($ORdata->{'Foils'}));
+    my %Foildata = %{$ORdata->{'Foils'}};
+    my @Foils = sort(keys(%Foildata));
+    my %Concepts;
     foreach my $foilid (@Foils) {
-        my $value = $ORdata->{'Foiltext'}->{$foilid};
-        &Apache::lonnet::logthis('row label '.$foilid.' = '.$value);
-        $Row_Label{$foilid} = $ORdata->{'Foiltext'}->{$foilid};
+        push(@{$Concepts{$Foildata{$foilid}->{'Concept'}}},
+             $foilid);
     }
-    my @Rows;
-    $Rows[0] = ['<td>&nbsp;</td>'];
-    for (my $i=$mintries;$i<=$maxtries;$i++) {
-        push (@{$Rows[0]},
-              '<th colspan="3">'.&mt('Attempt').' '.$i.'</th>');
+    undef(@Foils);
+    # Having gathered the concept information in a hash, we now translate it
+    # into an array because we need to be consistent about order.
+    # Also put the foils in order, too.
+    my $sortfunction = sub {
+        my %Numbers = (one   => 1,
+                       two   => 2,
+                       three => 3,
+                       four  => 4,
+                       five  => 5,
+                       six   => 6,
+                       seven => 7,
+                       eight => 8,
+                       nine  => 9,
+                       ten   => 10,);
+        my $a1 = $a; 
+        my $b1 = $b;
+        if (exists($Numbers{lc($a)})) {
+            $a1 = $Numbers{lc($a)};
+        }
+        if (exists($Numbers{lc($b)})) {
+            $b1 = $Numbers{lc($b)};
+        }
+        $a1 cmp $b1;
+    };
+    my @Concepts;
+    foreach my $concept (sort $sortfunction (keys(%Concepts))) {
+        push(@Concepts,{ name => $concept,
+                        foils => [@{$Concepts{$concept}}]});
+        push(@Foils,(@{$Concepts{$concept}}));
     }
-    $Rows[1] = ['<th>'.&mt('Foil').'</th>'];
-    for (my $i=$mintries;$i<=$maxtries;$i++) {
-        push (@{$Rows[1]},('<th>'.&mt('Correct').'</th>',
-                           '<th>'.&mt('Incorrect').'</th>',
-                           '<th>'.&mt('Percent Correct').'</th>',
-                           ));
-    }
-    my @PlotData;
-    my @CumulativePlotData;
-    my $index = 1;
-    foreach my $foilid (@Foils) {
-        my @Data = ('<td>'.$index.' '.$Row_Label{$foilid}.'</td>');
-        for (my $i=$mintries;$i<=$maxtries;$i++) {
-            push(@Data,
-                 ('<td>'.$ResponseData{$foilid}->[$i]->{'correct'}.'</td>',
-                  '<td>'.$ResponseData{$foilid}->[$i]->{'incorrect'}.
-                  '</td>',
-                  '<td>'.
-                  sprintf("%4.2f",
-                          $ResponseData{$foilid}->[$i]->{'percent_corr'}).
-                  '</td>'));
-            #
-            # Gather the per-attempt data
-            push (@{$PlotData[$i]->{'good'}},
-                  $ResponseData{$foilid}->[$i]->{'percent_corr'});
-            push (@{$PlotData[$i]->{'bad'}},
-                  100-$ResponseData{$foilid}->[$i]->{'percent_corr'});
-        }
-        for (my $i=0;$i<=$maxtries;$i++) {
-            push (@{$CumulativePlotData[$i]->{'good'}},
-                  $CumulativePlotData[-1]->{'good'}+
-                  $ResponseData{$foilid}->[$i]->{'correct'});
-            push (@{$CumulativePlotData[$i]->{'bad'}},
-                  $CumulativePlotData[-1]->{'bad'}+
-                  $ResponseData{$foilid}->[$i]->{'incorrect'});
+    #
+    # Build up the table of row labels.
+    my $table = '<table border="1" >'."\n";
+    if (@Concepts > 1) {
+        $table .= '<tr>'.
+            '<th>'.&mt('Concept Number').'</th>'.
+            '<th>'.&mt('Concept').'</th>'.
+            '<th>'.&mt('Foil Number').'</th>'.
+            '<th>'.&mt('Foil Name').'</th>'.
+            '<th>'.&mt('Foil Text').'</th>'.
+            '<th>'.&mt('Correct Value').'</th>'.
+            "</tr>\n";
+    } else {
+        $table .= '<tr>'.
+            '<th>'.&mt('Foil Number').'</th>'.
+            '<th>'.&mt('Foil Name').'</th>'.
+            '<th>'.&mt('Foil Text').'</th>'.
+            '<th>'.&mt('Correct Value').'</th>'.
+            "</tr>\n";
+    }        
+    my $conceptindex = 1;
+    my $foilindex = 1;
+    foreach my $concept (@Concepts) {
+        my @FoilsInConcept = @{$concept->{'foils'}};
+        my $firstfoil = shift(@FoilsInConcept);
+        if (@Concepts > 1) {
+            $table .= '<tr>'.
+                '<td>'.$conceptindex.'</td>'.
+                '<td>'.$concept->{'name'}.'</td>'.
+                '<td>'.$foilindex++.'</td>'.
+                '<td>'.$Foildata{$firstfoil}->{'name'}.'</td>'.
+                '<td>'.$Foildata{$firstfoil}->{'text'}.'</td>'.
+                '<td>'.$Foildata{$firstfoil}->{'value'}.'</td>'.
+                "</tr>\n";
+        } else {
+            $table .= '<tr>'.
+                '<td>'.$foilindex++.'</td>'.
+                '<td>'.$Foildata{$firstfoil}->{'name'}.'</td>'.
+                '<td>'.$Foildata{$firstfoil}->{'text'}.'</td>'.
+                '<td>'.$Foildata{$firstfoil}->{'value'}.'</td>'.
+                "</tr>\n";
+        }
+        foreach my $foilid (@FoilsInConcept) {
+            if (@Concepts > 1) {
+                $table .= '<tr>'.
+                    '<td></td>'.
+                    '<td></td>'.
+                    '<td>'.$foilindex.'</td>'.
+                    '<td>'.$Foildata{$foilid}->{'name'}.'</td>'.
+                    '<td>'.$Foildata{$foilid}->{'text'}.'</td>'.
+                    '<td>'.$Foildata{$foilid}->{'value'}.'</td>'.
+                    "</tr>\n";
+            } else {
+                $table .= '<tr>'.
+                    '<td>'.$foilindex.'</td>'.
+                    '<td>'.$Foildata{$foilid}->{'name'}.'</td>'.
+                    '<td>'.$Foildata{$foilid}->{'text'}.'</td>'.
+                    '<td>'.$Foildata{$foilid}->{'value'}.'</td>'.
+                    "</tr>\n";
+            }                
+        } continue {
+            $foilindex++;
         }
-        push(@Rows,\@Data);
     } continue {
-        $index++;
+        $conceptindex++;
+    }
+    $table .= "</table>\n";
+    #
+    # Build option index with color stuff
+    return ($table,\@Foils,\@Concepts);
+}
+
+sub build_option_index {
+    my ($ORdata)= @_;
+    my $table = "<table>\n";
+    my $optionindex = 0;
+    my @Rows;
+    foreach my $option (&mt('correct option chosen'),@{$ORdata->{'Options'}}) {
+        push (@Rows,
+              '<tr>'.
+              '<td bgcolor="'.$plotcolors->[$optionindex++].'">'.
+              ('&nbsp;'x4).'</td>'.
+              '<td>'.$option.'</td>'.
+              "</tr>\n");
+    }
+    $table .= join('',reverse(@Rows));
+    $table .= "</table>\n";
+}
+
+#########################################################
+#########################################################
+##
+##         Tries Analysis
+##
+#########################################################
+#########################################################
+sub tries_analysis {
+    my ($PerformanceData,$ORdata) = @_;
+    my $mintries = 1;
+    my $maxtries = $ENV{'form.NumPlots'};
+    my ($table,$Foils,$Concepts) = &build_foil_index($ORdata);
+    if ((@$Concepts < 2) && ($ENV{'form.AnalyzeAs'} ne 'Foils')) {
+        $table = '<h3>'.
+            &mt('Not enough data for concept analysis.  '.
+                'Performing Foil Analysis').
+            '</h3>'.$table;
+        $ENV{'form.AnalyzeAs'} = 'Foils';
     }
-    my @Data = ('<td></td>');
+    my %ResponseData = &analyze_option_data_by_tries($PerformanceData,
+                                                     $mintries,$maxtries);
+    #
+    # Compute the data neccessary to make the plots
+    my @PlotData;   # Array which holds the data for each plot
+                    # @{$PlotData[$try]->{'datasetname'}} holds the data for
+                    # try $try with respect to 'datasetname'.  The array is
+                    # filled either with per-foil or per-concept data.
+    my ($extrakey,$xlabel,$ylabel);
+    if ($ENV{'form.AnalyzeAs'} eq 'Foils') {
+        $extrakey = &build_option_index($ORdata);
+        $xlabel = 'Foil Number';
+        $ylabel = 'Percent Choosing Option';
+        foreach my $foilid (@$Foils) {
+            for (my $i=$mintries;$i<=$maxtries;$i++) {
+                foreach my $option ('_correct',@{$ORdata->{'Options'}}) {
+                    push(@{$PlotData[$i]->{'_total'}},
+                         $ResponseData{$foilid}->[$i]->{'_total'});
+                    if ($ResponseData{$foilid}->[$i]->{'_total'} == 0) {
+                        push (@{$PlotData[$i]->{$option}},0);
+                    } else {
+                        push (@{$PlotData[$i]->{$option}},
+                              100 * $ResponseData{$foilid}->[$i]->{$option} / 
+                                    $ResponseData{$foilid}->[$i]->{'_total'});
+                    }
+                }
+            }
+        }
+    } else {
+        # Concept analysis
+        #
+        # Note: we do not bother with characterizing the students incorrect
+        # answers at the concept level because an incorrect answer for one foil
+        # may be a correct answer for another foil.
+        $extrakey = '';
+        $xlabel = 'Concept Number';
+        $ylabel = 'Percent Correct';
+        my %ConceptData;
+        foreach my $concept (@{$Concepts}) {
+            for (my $i=$mintries;$i<=$maxtries;$i++) {
+                #
+                # Gather the per-attempt data
+                my $cdata = $ConceptData{$concept}->[$i];
+                foreach my $foilid (@{$concept->{'foils'}}) {
+                    $cdata->{'_correct'} += 
+                        $ResponseData{$foilid}->[$i]->{'_correct'};
+                    $cdata->{'_total'}   += 
+                        $ResponseData{$foilid}->[$i]->{'_total'};
+                }
+                push (@{$PlotData[$i]->{'_total'}},$cdata->{'_total'});
+                if ($cdata->{'_total'} == 0) {
+                    push (@{$PlotData[$i]->{'_correct'}},0);
+                } else {
+                    push (@{$PlotData[$i]->{'_correct'}},
+                          100*$cdata->{'_correct'}/$cdata->{'_total'});
+                }
+            }
+        }
+    } # End of work to fill @PlotData
+    # 
+    # Build a table for the plots
+    $table .= "<table>\n";
+    my @Plots;
     for (my $i=$mintries;$i<=$maxtries;$i++) {
-        push(@Data,'<td colspan="3">'.&DrawGraph('Attempt '.$i,'Foil Number',
-                                     'Percent Correct',100,
-                                     $PlotData[$i]->{'good'},
-                                     $PlotData[$i]->{'bad'}).'</td>');
+        my $minstu = $PlotData[$i]->{'_total'}->[0];
+        my $maxstu = $PlotData[$i]->{'_total'}->[0];
+        foreach my $count (@{$PlotData[$i]->{'_total'}}) {
+            if ($minstu > $count) {
+                $minstu = $count;
+            }
+            if ($maxstu < $count) {
+                $maxstu = $count;
+            }
+        }
+        $maxstu = 0 if (! defined($maxstu));
+        $minstu = 0 if (! defined($minstu));
+        my $title;
+        if ($maxstu == $minstu) {
+            $title = 'Attempt '.$i.', '.$maxstu.' students';
+        } else {
+            $title = 'Attempt '.$i.', '.$minstu.'-'.$maxstu.' students';
+        }
+        my @Datasets;
+        foreach my $option ('_correct',@{$ORdata->{'Options'}}) {
+            next if (! exists($PlotData[$i]->{$option}));
+            push(@Datasets,$PlotData[$i]->{$option});
+        }
+        my $graphlink = &Apache::loncommon::DrawGraph($title,
+                                                      $xlabel,
+                                                      $ylabel,
+                                                      100,
+                                                      $plotcolors,
+                                                      @Datasets);
+        push(@Plots,$graphlink);
     }
-    push (@Rows,\@Data);
-    my $table = '<table border="1" >'."\n";
-    for (my $i=0; $i <=$#Rows;$i++) {
-        $table .= '<tr>'.join('',@{$Rows[$i]})."</tr>\n";
+    #
+    # Should this be something the user can set?  Too many dialogs!
+    while (my $plotlink = shift(@Plots)) {
+        $table .= '<tr><td>'.$plotlink.'</td><td>'.$extrakey."</td></tr>\n";
     }
-    $table .= '</table>';
+    $table .= "</table>\n";
     return ($table);
 }
 
 sub analyze_option_data_by_tries {
-    my ($data,$mintries,$maxtries) = @_;
+    my ($PerformanceData,$mintries,$maxtries) = @_;
     my %Trydata;
     $mintries = 1         if (! defined($mintries) || $mintries < 1);
     $maxtries = $mintries if (! defined($maxtries) || $maxtries < $mintries);
-    foreach my $row (@$data) {
+    foreach my $row (@$PerformanceData) {
+        next if (! defined($row));
         my ($grading,$submission,$time,$tries) = @$row;
+        next if ($grading eq 'MISSING_ANSWER');
         my @Foilgrades = split('&',$grading);
         my @Foilsubs   = split('&',$submission);
         for (my $numtries = 1; $numtries <= $maxtries; $numtries++) {
             if ($tries == $numtries) {
-                foreach my $foilgrade (@Foilgrades) {
-                    my ($foilid,$correct) = split('=',$foilgrade);
+                for (my $i=0;$i<=$#Foilgrades;$i++) {
+                    my ($foilid,$correct)  = split('=',$Foilgrades[$i]);
+                    my (undef,$submission) = split('=',$Foilsubs[$i]);
+                    $submission = &Apache::lonnet::unescape($submission);
                     if ($correct) {
-                        $Trydata{$foilid}->[$numtries]->{'correct'}++;
+                        $Trydata{$foilid}->[$numtries]->{'_correct'}++;
                     } else {
-                        $Trydata{$foilid}->[$numtries]->{'incorrect'}++;
+                        $Trydata{$foilid}->[$numtries]->{$submission}++;
                     }                        
+                    $Trydata{$foilid}->[$numtries]->{'_total'}++;
                 }
             }
         }
     }
-    foreach my $foilid (keys(%Trydata)) {
-        foreach my $tryhash (@{$Trydata{$foilid}}) {
-            next if ((! exists($tryhash->{'correct'}) && 
-                      ! exists($tryhash->{'incorrect'})) ||
-                     ($tryhash->{'correct'} < 1 &&
-                      $tryhash->{'incorrect'} < 1));
-            $tryhash->{'percent_corr'} = 100 *
-                ($tryhash->{'correct'} /
-                         ($tryhash->{'correct'} + $tryhash->{'incorrect'})
-                 );
-        }
-    }
     return %Trydata;
 }
 
-sub DrawGraph {
-    my ($title,$xlabel,$ylabel,$MaxY,$values1,$values2)=@_;
-    $title  = '' if (! defined($title));
-    $xlabel = '' if (! defined($xlabel));
-    $ylabel = '' if (! defined($ylabel));
-    $title = &Apache::lonnet::escape($title);
-    $xlabel = &Apache::lonnet::escape($xlabel);
-    $ylabel = &Apache::lonnet::escape($ylabel);
-    #
-    my $sendValues1 = join(',', @$values1);
-    my $sendValues2;
-    if (defined($values2)) {
-        $sendValues2 = join(',', @$values2);
-    }
-            
-    my $sendCount = scalar(@$values1);
-    $MaxY =1 if ($MaxY < 1);
-    if ( int($MaxY) < $MaxY ) {
-        $MaxY++;
-        $MaxY = int($MaxY);
-    }
-    my @GData = ($title,$xlabel,$ylabel,$MaxY,$sendCount,$sendValues1);
-    if (defined($sendValues2)) {
-        push (@GData,$sendValues2);
+#########################################################
+#########################################################
+##
+##                 Time Analysis
+##
+#########################################################
+#########################################################
+sub time_analysis {
+    my ($PerformanceData,$ORdata) = @_;
+    my $num_plots = $ENV{'form.NumPlots'};
+    my ($table,$Foils,$Concepts) = &build_foil_index($ORdata);
+    my $num_data = scalar(@$PerformanceData)-1;
+    my $percent = sprintf('%2f',100/$num_plots);
+    my $extratable = '';
+    if ($ENV{'form.AnalyzeAs'} eq 'Foils') {
+        $extratable = &build_option_index($ORdata);
+    }
+    $table .= "<table>\n";
+    for (my $i=0;$i<$num_plots;$i++) {
+        my $starttime = &Apache::lonhtmlcommon::get_date_from_form
+            ('startdate_'.$i);
+        my $endtime = &Apache::lonhtmlcommon::get_date_from_form
+            ('enddate_'.$i);
+        my ($begin_index,$end_index,$plottitle,$plothtml,$data);
+        if (! defined($starttime) || ! defined($endtime)) {
+            $begin_index = $i*int($num_data/$num_plots);
+            $end_index = ($i+1)*int($num_data/$num_plots);
+            my $lownum  = sprintf('%2.1f',$i*$percent);
+            $lownum =~ s/(\.0)$//;
+            my $highnum = sprintf('%2.1f',($i+1)*$percent);
+            $highnum =~ s/(\.0)$//;
+            $plottitle = $lownum.'% to '.$highnum.'% of submissions';
+        } else {
+            my $j;
+            while (++$j < scalar(@$PerformanceData)) {
+                last if ($PerformanceData->[$j]->[2] > $starttime);
+            }
+            $begin_index = $j;
+            while (++$j < scalar(@$PerformanceData)) {
+                last if ($PerformanceData->[$j]->[2] > $endtime);
+            }
+            $end_index = $j;
+            $plottitle = $ENV{'form.plottitle_'.$i};
+        }
+        ($plothtml,$starttime,$endtime,$data) = 
+            &analyze_option_data_by_time($PerformanceData,
+                                         $begin_index,$end_index,
+                                         $plottitle,$Foils,
+                                         $Concepts,$ORdata);
+        my $startdateform = &Apache::lonhtmlcommon::date_setter
+            ('Statistics','startdate_'.$i,$starttime);
+        my $enddateform = &Apache::lonhtmlcommon::date_setter
+            ('Statistics','enddate_'.$i,$endtime);
+        $table.="<tr><td>".$plothtml.'</td><td align="left" valign="top">'.
+            "<b>Start Time</b>: &nbsp;".$startdateform."<br />".
+            "<b>End Time</b>&nbsp;&nbsp;: "."&nbsp;".$enddateform."<br />".
+            '<b>Plot Title</b>&nbsp;&nbsp;:'.("&nbsp;"x3).
+            '<input type="text" size="30" name="plottitle_'.$i.'" value="'.
+                  &HTML::Entities::encode($plottitle).'" /><br />'.$extratable.
+            "</td></tr>\n";
     }
-    return '<IMG src="/cgi-bin/graph.png?'.
-        (join('&', @GData)).'" border="1" />';
+    $table .="</table>\n";
+    return $table;
 }
 
-
-
-sub get_problem_symb {
-    my $problemstring = shift();
-    my ($symb,$partid,$resid) = ($problemstring=~ /^(.*):([^:]*):([^:]*)$/);
-    return ($symb,$partid,$resid);
+sub analyze_option_data_by_time {
+    my ($PerformanceData,$begin_index,
+        $end_index,$description,$Foils,$Concepts,$ORdata) = @_;
+    my %TimeData;
+    #
+    # Get the start and end times for this segment of the plot
+    my $starttime = $PerformanceData->[$begin_index]->[2];
+    my $endtime   = $PerformanceData->[$end_index  ]->[2];
+    #
+    # Compute the number getting the foils correct or incorrects
+    for (my $i=$begin_index;$i<=$end_index;$i++) {
+        my $row = $PerformanceData->[$i];
+        next if (! defined($row));
+        my ($grading,$submission,$time,$tries) = @$row;
+        next if ($grading eq 'MISSING_ANSWER');
+        my @Foilgrades = split('&',$grading);
+        my @Foilsubs   = split('&',$submission);
+        for (my $j=0;$j<=$#Foilgrades;$j++) {
+            my ($foilid,$correct)  = split('=',$Foilgrades[$j]);
+            my (undef,$submission) = split('=',$Foilsubs[$j]);
+            if ($correct) {
+                $TimeData{$foilid}->{'_correct'}++;
+            } else {
+                $submission = &HTML::Entities::decode($submission);
+                $submission =~ s/\%20/ /g;
+                $TimeData{$foilid}->{$submission}++;
+            }
+            $TimeData{$foilid}->{'_total'}++;
+        }
+    }
+    #
+    # Compute the total and percent correct
+    my @Plotdata;
+    my ($xlabel,$ylabel);
+    if ($ENV{'form.AnalyzeAs'} eq 'Foils') {
+        $xlabel = 'Foil Number';
+        $ylabel = 'Option Chosen';
+        foreach my $foil (@$Foils) {
+            my $total = $TimeData{$foil}->{'_total'};
+            my $optionidx = 0;
+            foreach my $option ('_correct',@{$ORdata->{'Options'}}) {
+                if ($total > 0) {
+                    push(@{$Plotdata[$optionidx]},
+                         100 * $TimeData{$foil}->{$option} / $total);
+                } else {
+                    push(@{$Plotdata[$optionidx]},0);
+                }
+            } continue {
+                $optionidx++;
+            }
+        }
+    } else {
+        $xlabel = 'Concept Number';
+        $ylabel = 'Percent Correct';
+        foreach my $concept (@$Concepts) {
+            my $correct;
+            my $total;
+            foreach my $foil (@{$concept->{'foils'}}) {
+                $correct+=$TimeData{$foil}->{'_correct'};
+                $total  +=$TimeData{$foil}->{'_total'};
+            }
+            if ($total > 0) {
+                push(@{$Plotdata[0]},100 * $correct / $total);
+            } else {
+                push(@{$Plotdata[0]},0);
+            }
+        }
+    }
+    #
+    # Create the plot
+    my $graphlink = &Apache::loncommon::DrawGraph
+        ($description,#'Time Interval Analysis',
+         $xlabel,
+         $ylabel,
+         100,
+         $plotcolors,
+         @Plotdata);
+    #
+    return ($graphlink,$starttime,$endtime,\%TimeData);
 }
 
+#########################################################
+#########################################################
+##
+##             Interface 
+##
+#########################################################
+#########################################################
 sub CreateInterface {
+    ##
+    ## Environment variable initialization
+    if (! exists$ENV{'form.AnalyzeOver'}) {
+        $ENV{'form.AnalyzeOver'} = 'Tries';
+    }
+    ##
+    ## Build the menu
     my $Str = '';
     $Str .= '<table cellspacing="5">'."\n";
     $Str .= '<tr>';
     $Str .= '<td align="center"><b>'.&mt('Sections').'</b></td>';
     $Str .= '<td align="center"><b>'.&mt('Enrollment Status').'</b></td>';
-    $Str .= '<td align="center"><b>'.&mt('Sequences and Folders').'</b></td>';
+#    $Str .= '<td align="center"><b>'.&mt('Sequences and Folders').'</b></td>';
+    $Str .= '<td align="center">&nbsp;</td>';
     $Str .= '</tr>'."\n";
-    #
+    ##
+    ## 
     $Str .= '<tr><td align="center">'."\n";
     $Str .= &Apache::lonstatistics::SectionSelect('Section','multiple',5);
-    $Str .= '</td><td align="center">';
+    $Str .= '</td>';
+    #
+    $Str .= '<td align="center">';
     $Str .= &Apache::lonhtmlcommon::StatusOptions(undef,undef,5);
-    $Str .= '</td><td align="center">';
+    $Str .= '</td>';
+    #
+#    $Str .= '<td align="center">';
     my $only_seq_with_assessments = sub { 
         my $s=shift;
         if ($s->{'num_assess'} < 1) { 
@@ -259,16 +620,63 @@ sub CreateInterface {
             return 1;
         }
     };
-    $Str .= &Apache::lonstatistics::MapSelect('Maps','multiple,all',5,
+    &Apache::lonstatistics::MapSelect('Maps','multiple,all',5,
                                               $only_seq_with_assessments);
-    $Str .= '</td></tr>'."\n";
+    ##
+    ##
+    $Str .= '<td>';
+    { # These braces are here to organize the code, not scope it.
+        {
+            $Str .= '<nobr>'.&mt('Analyze Over ');
+            $Str .='<select name="AnalyzeOver" >';
+            $Str .= '<option value="Tries" ';
+            if (! exists($ENV{'form.AnalyzeOver'}) || 
+                $ENV{'form.AnalyzeOver'} eq 'Tries'){
+                # Default to Tries
+                $Str .= ' selected ';
+            }
+            $Str .= '>'.&mt('Tries').'</option>';
+            $Str .= '<option value="Time" ';
+            $Str .= ' selected ' if ($ENV{'form.AnalyzeOver'} eq 'Time');
+            $Str .= '>'.&mt('Time').'</option>';
+            $Str .= '</select></nobr><br />';
+        }
+        {
+            $Str .= '<nobr>'.&mt('Analyze as ');
+            $Str .='<select name="AnalyzeAs" >';
+            $Str .= '<option value="Concepts" ';
+            if (! exists($ENV{'form.AnalyzeAs'}) || 
+                $ENV{'form.AnalyzeAs'} eq 'Concepts'){
+                # Default to Concepts
+                $Str .= ' selected ';
+            }
+            $Str .= '>'.&mt('Concepts').'</option>';
+            $Str .= '<option value="Foils" ';
+            $Str .= ' selected ' if ($ENV{'form.AnalyzeAs'} eq 'Foils');
+            $Str .= '>'.&mt('Foils').'</option>';
+            $Str .= '</select></nobr><br />';
+        }
+        {
+            $Str .= '<br /><nobr>'.&mt('Number of Plots:');
+            $Str .= '<select name="NumPlots">';
+            if (! exists($ENV{'form.NumPlots'}) 
+                || $ENV{'form.NumPlots'} < 1 
+                || $ENV{'form.NumPlots'} > 20) {
+                $ENV{'form.NumPlots'} = 5;
+            }
+            foreach my $i (1,2,3,4,5,6,7,8,10,15,20) {
+                $Str .= '<option value="'.$i.'" ';
+                if ($ENV{'form.NumPlots'} == $i) { $Str.=' selected '; }
+                $Str .= '>'.$i.'</option>';
+            }
+            $Str .= '</select></nobr>';
+        }
+    }
+    $Str .= '</td>';
+    ##
+    ##
+    $Str .= '</tr>'."\n";
     $Str .= '</table>'."\n";
-    $Str .= '<input type="submit" name="ProblemAnalysis" value="'.
-        &mt('Analyze Problem').'" />';
-    $Str .= '&nbsp;'x5;
-    $Str .= '<input type="submit" name="ClearCache" value="'.
-        &mt('Clear Caches').'" />';
-    $Str .= '&nbsp;'x5;
     return ($Str);
 }
 
@@ -279,8 +687,7 @@ sub OptionResponseProblemSelector {
         next if ($seq->{'num_assess'}<1);
         my $seq_str = '';
         foreach my $res (@{$seq->{'contents'}}) {
-#            &Apache::lonnet::logthis('checking '.$res->{'title'});
-#            next if ($res->{'type'} ne 'assessment');
+            next if ($res->{'type'} ne 'assessment');
             foreach my $part (@{$res->{'parts'}}) {
                 my $partdata = $res->{'partdata'}->{$part};
                 if (! exists($partdata->{'option'}) || 
@@ -317,6 +724,19 @@ sub OptionResponseProblemSelector {
     return $Str;
 }
 
+#########################################################
+#########################################################
+##
+##              Misc functions
+##
+#########################################################
+#########################################################
+sub get_problem_symb {
+    my $problemstring = shift();
+    my ($symb,$partid,$resid) = ($problemstring=~ /^(.*):([^:]*):([^:]*)$/);
+    return ($symb,$partid,$resid);
+}
+
 sub get_resource_from_symb {
     my ($symb) = @_;
     foreach my $seq (&Apache::lonstatistics::Sequences_with_Assess()) {
@@ -329,20 +749,17 @@ sub get_resource_from_symb {
     return undef;
 }
 
+##
+## get problem data and put it into a useful data structure.
+## note: we must force each foil and option to not begin or end with
+##       spaces as they are stored without such data.
+##
 sub get_problem_data {
     my ($url) = @_;
-#    my $Answ=&Apache::lonnet::ssi($URI,('grade_target' => 'analyze',
-#                                  'grade_username' => $sname,
-#                                  'grade_domain' => $sdom,
-#                                  'grade_courseid' => $cid,
-#                                  'grade_symb' => $symb));
     my $Answ=&Apache::lonnet::ssi($url,('grade_target' => 'analyze'));
     (my $garbage,$Answ)=split(/_HASH_REF__/,$Answ,2);
     my %Answer;
     %Answer=&Apache::lonnet::str2hash($Answ);
-#    &Apache::lonnet::logthis('keys of %Answer = '.join(', ',(keys(%Answer))));
-#    &Apache::lonnet::logthis('$Answer{parts} = '.
-#                             join(', ',@{$Answer{'parts'}}));
     my %Partdata;
     foreach my $part (@{$Answer{'parts'}}) {
         while (my($key,$value) = each(%Answer)) {
@@ -356,45 +773,22 @@ sub get_problem_data {
                 } elsif ($key =~ /^concept\.(.*)$/) {
                     my $concept = $1;
                     foreach my $foil (@$value) {
-                        $Partdata{$part}->{$foil}->{'Concept'}=$concept;
+                        $Partdata{$part}->{'Foils'}->{$foil}->{'Concept'}=
+                                                                      $concept;
                     }
                 }
-                &Apache::lonnet::logthis($part.' '.$key.' (array) = '.
-                                         join(', ',@$value));
             } else {
-                $value =~ s/^\s*//g;
-                $value =~ s/\s*$//g;
                 if ($key=~ /^foil\.text\.(.*)$/) {
                     my $foil = $1;
-                    $Partdata{$part}->{'Foiltext'}->{$foil}=$value;
+                    $Partdata{$part}->{'Foils'}->{$foil}->{'name'}=$foil;
+                    $Partdata{$part}->{'Foils'}->{$foil}->{'text'}=$value;
                 } elsif ($key =~ /^foil\.value\.(.*)$/) {
                     my $foil = $1;
-                    $Partdata{$part}->{'FoilValues'}->{$foil}=$value;
+                    $Partdata{$part}->{'Foils'}->{$foil}->{'value'}=$value;
                 }
-                &Apache::lonnet::logthis($part.' '.$key.' = '.$value);
             }
         }
     }
-
-#    my $parts='';
-#    foreach my $elm (@{$Answer{"parts"}}) {
-#        $parts.="$elm,";
-#    }
-#    chop($parts);
-#    my $conc='';
-#    foreach my $elm (@{$Answer{"$parts.concepts"}}) {
-#        $conc.="$elm@";
-#    }
-#    chop($conc);
-#
-#    @Concepts=split(/\@/,$conc);
-#    foreach my $concept (@{$Answer{"$parts.concepts"}}) {
-#        foreach my $foil (@{$Answer{"$parts.concept.$concept"}}) {
-#            $foil_to_concept{$foil} = $concept;
-#            #$ConceptData{$foil} = $Answer{"$parts.foil.value.$foil"};
-#        }
-#    }
-#    return $symb;
     return %Partdata;
 }