--- loncom/interface/lonpreferences.pm	2022/08/19 18:56:41	1.240
+++ loncom/interface/lonpreferences.pm	2022/09/08 01:41:13	1.241
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Preferences
 #
-# $Id: lonpreferences.pm,v 1.240 2022/08/19 18:56:41 raeburn Exp $
+# $Id: lonpreferences.pm,v 1.241 2022/09/08 01:41:13 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -31,7 +31,6 @@
 package Apache::lonpreferences;
 
 use strict;
-use LONCAPA;
 use Apache::Constants qw(:common);
 use Apache::File;
 use Apache::loncommon();
@@ -40,6 +39,7 @@ use Apache::lonlocal;
 use Apache::lonnet;
 use LONCAPA::lonauthcgi();
 use LONCAPA();
+use DateTime::TimeZone();
 
 ################################################################
 #                       Handler subroutines                    #
@@ -2218,6 +2218,120 @@ sub verify_and_change_lockednames {
     &print_main_menu($r,$message);
 }
 
+sub timezonechanger {
+    my $r = shift;
+    my $uname = $env{'user.name'};
+    my $udom = $env{'user.domain'};
+    if (&Apache::lonnet::usertools_access($uname,$udom,'timezone')) {
+        my $js = <<"ENDSCRIPT";
+<script type-"text/javascript">
+// <![CDATA[
+function toggleTZdisplay(form) {
+    var radioname = 'settimezone';
+    var divid = 'LC_timezone_selector';
+    var num = form.elements[radioname].length;
+    if (num) {
+        var setvis = '';
+        for (var i=0; i<num; i++) {
+            if (form.elements[radioname][i].checked) {
+                if (form.elements[radioname][i].value == '1') {
+                    if (document.getElementById(divid)) {
+                        document.getElementById(divid).style.display = 'inline-block';
+                    }
+                    setvis = 1;
+                }
+                break;
+            }
+        }
+        if (!setvis) {
+            if (document.getElementById(divid)) {
+                document.getElementById(divid).style.display = 'none';
+            }
+        }
+    }
+    return;
+}
+// ]]>
+</script>
+ENDSCRIPT
+        my %loaditems = (
+                           onload => 'javascript:toggleTZdisplay(document.prefs);',
+                        );
+        my $args = { 'add_entries' => \%loaditems };
+        &Apache::lonhtmlcommon::add_breadcrumb(
+                {   href => '/adm/preferences?action=',
+                    text => 'Set Your Time Zone'});
+        $r->print(Apache::loncommon::start_page('Set Your Time Zone',$js,$args));
+        $r->print(Apache::lonhtmlcommon::breadcrumbs('Set Your Time Zone'));
+        my %userenv = &Apache::lonnet::get('environment',['timezone']);
+        my $timezone = $userenv{'timezone'};
+        my %lt = &Apache::lonlocal::texthash(
+                     lctz  => 'Use Time Zone set by LON-CAPA',
+                     owntz => 'Use Time Zone set by you',
+                     save  => 'Save',
+        );
+        my (%checked,$tzsty);
+        if ($userenv{'timezone'} ne '') {
+            $checked{'owntz'} = ' checked="checked"';
+            $tzsty = 'inline-block';
+        } else {
+            $checked{'lctz'} = ' checked="checked"';
+            $tzsty = 'none';
+        }
+        my $onclick = ' onclick="javascript:toggleTZdisplay(this.form);"';
+        my $selector = &Apache::loncommon::select_timezone('timezone',$timezone,undef,1);
+        $r->print(<<"END");
+<form name="prefs" action="/adm/preferences" method="post">
+<input type="hidden" name="action" value="verify_and_change_timezone" />
+<span class="LC_nobreak">
+<label><input type="radio" name="settimezone" value="0"$checked{'lctz'}$onclick />
+$lt{'lctz'}</label>&nbsp;&nbsp;&nbsp;&nbsp;
+<label><input type="radio" name="settimezone" value="1"$checked{'owntz'}$onclick />
+$lt{'owntz'}</label><div style="display:$tzsty" id="LC_timezone_selector">&nbsp;
+$selector
+</div></span><br /><br />
+<input type="submit" value="$lt{'save'}" />
+</form>
+END
+    }
+    return;
+}
+
+sub verify_and_change_timezone {
+    my $r = shift;
+    my $currtimezone = $env{'environment.timezone'};
+    my $newtimezone;
+    if ($env{'form.settimezone'}) {
+        $newtimezone = $env{'form.timezone'};
+        if (DateTime::TimeZone->is_valid_name($env{'form.timezone'})) {
+            $newtimezone = $env{'form.timezone'};
+        }
+    }
+    my $message='';
+    if ($newtimezone) {
+        if ($newtimezone eq $currtimezone) {
+            $message = &mt('Time Zone settings unchanged');
+        } else {
+            &Apache::lonnet::put('environment',{'timezone' => $newtimezone});
+            &Apache::lonnet::appenv({'environment.timezone' => $newtimezone});
+            $message=&Apache::lonhtmlcommon::confirm_success(
+                &mt('Set [_1] to [_2]',
+                    '<i>'.&mt('Your Time Zone').'</i>',
+                    '<tt>"'.$newtimezone.'"</tt>.')).
+               '<br />';
+        }
+    } elsif ($currtimezone) {
+        &Apache::lonnet::del('environment',['timezone']);
+        &Apache::lonnet::delenv('environment.timezone');
+        $message=&Apache::lonhtmlcommon::confirm_success(&mt('Time Zone now set by LON-CAPA'));
+    } else {
+        $message = &mt('Time Zone settings unchanged');
+    }
+    $message=&Apache::loncommon::confirmwrapper($message);
+    &print_main_menu($r,$message);
+    return;
+}
+
 sub print_main_menu {
     my ($r, $message) = @_;
     # Determine current authentication method
@@ -2232,6 +2346,9 @@ my %permissions;
 if (&Apache::lonnet::usertools_access($user,$domain,'aboutme')) {
     $permissions{'aboutme'} = 'F';
 }
+if (&Apache::lonnet::usertools_access($user,$domain,'timezone')) {
+    $permissions{'timezone'} = 'F';
+}
 my @menu=
     ({	categorytitle=>'Personal Data',
 	items =>[
@@ -2274,6 +2391,14 @@ my @menu=
 		icon => 'dismath.png',
 		linktitle => 'Change how math is displayed.'
 	    },
+            {
+                linktext => 'Time Zone',
+                url => '/adm/preferences?action=changetimezone',
+                permission => $permissions{'timezone'},
+                #help => '',
+                icon => 'timezone.png',
+                linktitle => 'Set your time zone.',
+             }
 		]
     },
     {	categorytitle=>'Page Display Settings',
@@ -2532,6 +2657,10 @@ sub handler {
     } elsif ($env{'form.action'} eq 'verify_and_change_lockednames') {
         &verify_and_change_lockednames($r);
         $ended = 1;
+    } elsif ($env{'form.action'} eq 'changetimezone') {
+        &timezonechanger($r);
+    } elsif ($env{'form.action'} eq 'verify_and_change_timezone') {
+        &verify_and_change_timezone($r);
     }
 
     # Properly end the HTML page of all preference pages