--- loncom/interface/lonclonecourse.pm	2015/06/23 17:49:06	1.11
+++ loncom/interface/lonclonecourse.pm	2016/01/21 00:12:38	1.12
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # routines for clone a course
 #
-# $Id: lonclonecourse.pm,v 1.11 2015/06/23 17:49:06 musolffc Exp $
+# $Id: lonclonecourse.pm,v 1.12 2016/01/21 00:12:38 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -30,6 +30,8 @@
 package Apache::lonclonecourse;
 use LONCAPA;
 use Apache::lonnet;
+use DateTime();
+use DateTime::TimeZone;
 
 # ================================================ Get course directory listing
 
@@ -148,6 +150,22 @@ sub copyresourcedb {
     my $delta=$date_shift*60*60*24;
     my %origcrsdata=&Apache::lonnet::coursedescription($origcrsid);
     my %newcrsdata= &Apache::lonnet::coursedescription($newcrsid);
+    my $origtz;
+    if (($date_mode) && ($date_mode ne 'preserve') && ($date_shift) && 
+        (int($date_shift) == $date_shift)) {
+        $origtz = $origcrsdata{'timezone'};
+        if ($origtz eq '') {
+            my %domdefaults = &Apache::lonnet::get_domain_defaults($origcrsdata{'domain'});
+            if ($domdefaults{'timezone_def'} ne '') {
+                $origtz = $domdefaults{'timezone_def'};
+            }
+        }
+        if ($origtz eq '') {
+            $origtz = 'local';
+        } elsif (!DateTime::TimeZone->is_valid_name($origtz)) {
+            $origtz = 'local';
+        }
+    }
     my %data=&Apache::lonnet::dump
 	('resourcedata',$origcrsdata{'domain'},$origcrsdata{'num'});
     $origcrsid=~s/^\///;
@@ -195,14 +213,24 @@ sub copyresourcedb {
 # date_mode other: do not transfer dates
         if (($date_mode) && ($date_mode ne 'preserve')) {
 	    if ($data{$key.'.type'}=~/^date_(start|end)$/) {
-	       if ($date_mode eq 'shift') {
-		  $newdata{$thiskey}=$newdata{$thiskey}+$delta;
-	       } else {
-		  delete($newdata{$thiskey});
-		  delete($newdata{$thiskey.'.type'});
-	       }
+	        if ($date_mode eq 'shift') {
+                    if (($date_shift) && ($date_shift == int($date_shift))) { 
+                        my $dt = DateTime->from_epoch(epoch => $newdata{$thiskey})
+                                                      ->set_time_zone($origtz);
+                        if (($origtz eq 'local') && (!$ENV{TZ})) {
+                            $ENV{TZ} = $dt->time_zone()->name();
+                        }
+                        $dt->add(days => int($date_shift));
+                        $newdata{$thiskey} = $dt->epoch();
+                    } else {
+                        $newdata{$thiskey} = $newdata{$thiskey}+$delta;
+                    }
+                } else {
+                    delete($newdata{$thiskey});
+                    delete($newdata{$thiskey.'.type'});
+                }
             }
-	}
+        }
     }
     return &Apache::lonnet::put
 	('resourcedata',\%newdata,$newcrsdata{'domain'},$newcrsdata{'num'});