--- loncom/homework/lonhomework.pm	2025/01/17 15:05:47	1.394
+++ loncom/homework/lonhomework.pm	2025/06/28 14:35:00	1.395
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # The LON-CAPA Homework handler
 #
-# $Id: lonhomework.pm,v 1.394 2025/01/17 15:05:47 raeburn Exp $
+# $Id: lonhomework.pm,v 1.395 2025/06/28 14:35:00 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -600,10 +600,12 @@ sub check_access {
                 return ('SHOW_ANSWER');
             }
         }
-	foreach my $temp ("opendate","duedate","answerdate") {
+	foreach my $temp ("opendate","duedate","overduedate","answerdate") {
 	    $lastdate = $date;
 	    if ($temp eq 'duedate') {
 		$date = &due_date($id,$symb);
+            } elsif ($temp eq 'overduedate') {
+                $date = &overdue_date($id,$symb);
 	    } else {
 		$date = &Apache::lonnet::EXT("resource.$id.$temp",$symb);
 	    }
@@ -644,6 +646,9 @@ sub check_access {
 	} elsif ($type eq 'duedate') {
 	    $status='CAN_ANSWER';
 	    $datemsg = &mt('is due at [_1]',$date);
+        } elsif ($type eq 'overduedate') {
+            $status='CAN_ANSWER';
+            $datemsg = &mt('past-due grace period until [_1]',$date);
 	} elsif ($type eq 'answerdate') {
 	    $status='CLOSED';
 	    $datemsg = &mt('was due on [_1], and answers will be available on [_2]',
@@ -734,6 +739,76 @@ sub due_date {
     return $date;
 }
 
+sub overdue_date {
+    my ($part_id,$symb,$udom,$uname)=@_;
+    my $date;
+    my $duedate= &Apache::lonnet::EXT("resource.$part_id.duedate",$symb,
+                                       $udom,$uname);
+    if ($duedate ne '') {
+        my $grace = &Apache::lonnet::EXT("resource.$part_id.grace",$symb,
+                                         $udom,$uname);
+        if ($grace) {
+            my $grace_end = (split(/,/,$grace))[-1];
+            my ($offset) = split(/:/,$grace_end,2);
+            if ($offset > 0) {
+                $date = $offset + $duedate;
+            }
+        } 
+    }
+    return $date;
+}
+
+sub partial_credit_overdue {
+    my ($part_id,$symb,$udom,$uname)=@_;
+    my $reduction;
+    my $duedate = &Apache::lonnet::EXT("resource.$part_id.duedate",$symb,
+                                       $udom,$uname);
+    if ($duedate) {
+        my $grace = &Apache::lonnet::EXT("resource.$part_id.grace",$symb,
+                                         $udom,$uname); 
+        if ($grace) {
+            my $lateness = time - $duedate;
+            if ($lateness > 0) {
+                my ($start,$end,$startfrac,$endfrac,$usegrad);
+                $start = 0;
+                $startfrac = 1.0;
+                $usegrad = 0;
+                foreach my $item (split(/,/,$grace)) {
+                    my ($offset,$frac,$grad) = split(/:/,$item);
+                    if ($lateness > $offset) {
+                        $start = $offset;
+                        $startfrac = $frac;
+                        next;
+                    } elsif ($lateness <= $offset) {
+                        $end = $offset;
+                        $endfrac = $frac;
+                        $usegrad = $grad;
+                        last;
+                    }
+                }
+                if ($end) {
+                    if (($end == $start) || ($startfrac == $endfrac)) {
+                        $reduction = $endfrac;
+                    } elsif ($end - $start > 0) {
+                        if (($endfrac <= 1.0) && ($endfrac >= 0)) {
+                            $reduction = $endfrac;
+                            if ($usegrad) {
+                                my $decline = $startfrac - $endfrac;
+                                my $fraction = ($lateness - $start)/($end - $start);
+                                if (($fraction <= 1) && ($fraction >= 0)) {
+                                    my $value = $startfrac - ($decline*$fraction);
+                                    $reduction = sprintf("%.2f", $value);
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+    return $reduction;
+}
+
 sub seconds_to_human_length {
     my ($length)=@_;