--- loncom/localize/lonlocal.pm	2008/09/19 12:31:06	1.50
+++ loncom/localize/lonlocal.pm	2009/05/04 21:44:00	1.58
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Localization routines
 #
-# $Id: lonlocal.pm,v 1.50 2008/09/19 12:31:06 raeburn Exp $
+# $Id: lonlocal.pm,v 1.58 2009/05/04 21:44:00 lueken Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -173,9 +173,11 @@ require Exporter;
 our @ISA = qw (Exporter);
 our @EXPORT = qw(mt mtn ns mt_user);
 
+my %mtcache=();
+
 # ========================================================= The language handle
 
-use vars qw($lh);
+use vars qw($lh $current_language);
 
 # ===================================================== The "MakeText" function
 
@@ -191,7 +193,13 @@ sub mt (@) {
                 return $_[0];
             }
         } else {
-            return $lh->maketext(@_);
+            if ($#_>0) { return $lh->maketext(@_); }
+            if ($mtcache{$current_language.':'.$_[0]}) {
+               return $mtcache{$current_language.':'.$_[0]};
+            }
+            my $translation=$lh->maketext(@_);
+            $mtcache{$current_language.':'.$_[0]}=$translation;
+            return $translation; 
         }
     } else {
 	if (wantarray) {
@@ -233,14 +241,67 @@ sub current_language {
     return 'en';
 }
 
+sub preferred_languages {
+    my @languages=();
+    if (($Apache::lonnet::env{'request.role.adv'}) && ($Apache::lonnet::env{'form.languages'})) {
+        @languages=(@languages,split(/\s*(\,|\;|\:)\s*/,$Apache::lonnet::env{'form.languages'}));
+    }
+    if ($Apache::lonnet::env{'course.'.$Apache::lonnet::env{'request.course.id'}.'.languages'}) {
+        @languages=(@languages,split(/\s*(\,|\;|\:)\s*/,
+                 $Apache::lonnet::env{'course.'.$Apache::lonnet::env{'request.course.id'}.'.languages'}));
+    }
+
+    if ($Apache::lonnet::env{'environment.languages'}) {
+        @languages=(@languages,
+                    split(/\s*(\,|\;|\:)\s*/,$Apache::lonnet::env{'environment.languages'}));
+    }
+    my $browser=$ENV{'HTTP_ACCEPT_LANGUAGE'};
+    if ($browser) {
+        my @browser =
+            map { (split(/\s*;\s*/,$_))[0] } (split(/\s*,\s*/,$browser));
+        push(@languages,@browser);
+    }
+
+    foreach my $domtype ($Apache::lonnet::env{'user.domain'},$Apache::lonnet::env{'request.role.domain'},
+                         $Apache::lonnet::perlvar{'lonDefDomain'}) {
+        if ($domtype ne '') {
+            my %domdefs = &Apache::lonnet::get_domain_defaults($domtype);
+            if ($domdefs{'lang_def'} ne '') {
+                push(@languages,$domdefs{'lang_def'});
+            }
+        }
+    }
+    return &get_genlanguages(@languages);
+}
+
+sub get_genlanguages {
+    my (@languages) = @_;
+# turn "en-ca" into "en-ca,en"
+    my @genlanguages;
+    foreach my $lang (@languages) {
+        unless ($lang=~/\w/) { next; }
+        push(@genlanguages,$lang);
+        if ($lang=~/(\-|\_)/) {
+            push(@genlanguages,(split(/(\-|\_)/,$lang))[0]);
+        }
+    }
+    #uniqueify the languages list
+    my %count;
+    @genlanguages = map { $count{$_}++ == 0 ? $_ : () } @genlanguages;
+    return @genlanguages;
+}
+
 # ============================================================== What encoding?
 
 sub current_encoding {
     my $default='UTF-8';
-    if ($Apache::lonnet::env{'browser.os'} eq 'win' && 
-	$Apache::lonnet::env{'browser.type'} eq 'explorer') {
-        $default='ISO-8859-1';
-    }
+# UTF-8 character encoding needed for the whole LON-CAPA system
+# (interface language and homework problem content)
+# See Bugzilla 5702 vs. 2189 and 4067
+#    if ($Apache::lonnet::env{'browser.os'} eq 'win' && 
+#	$Apache::lonnet::env{'browser.type'} eq 'explorer') {
+#        $default='ISO-8859-1';
+#    }
     if ($lh) {
 	my $enc=$lh->maketext('char_encoding');
 	return ($enc eq 'char_encoding'?$default:$enc);
@@ -279,9 +340,10 @@ sub get_language_handle {
 	my $headers=$r->headers_in;
 	$ENV{'HTTP_ACCEPT_LANGUAGE'}=$headers->{'Accept-language'};
     }
-    my @languages=&Apache::loncommon::preferred_languages;
+    my @languages=&preferred_languages();
     $ENV{'HTTP_ACCEPT_LANGUAGE'}='';
     $lh=Apache::localize->get_handle(@languages);
+    $current_language=&current_language();
     if ($r) {
 	$r->content_languages([&current_language()]);
     }
@@ -290,15 +352,24 @@ sub get_language_handle {
 
 # ========================================================== Localize localtime
 sub gettimezone {
-    my $timezone; 
-    if ($Apache::lonnet::env{'course.'.$Apache::lonnet::env{'request.course.id'}.'.timezone'}) {
-        $timezone = $Apache::lonnet::env{'course.'.$Apache::lonnet::env{'request.course.id'}.'.timezone'};    
-    } elsif ($Apache::lonnet::env{'request.course.id'} ne '') {
-        my $cdom = $Apache::lonnet::env{'course.'.$Apache::lonnet::env{'request.course.id'}.'.domain'};
-        if ($cdom ne '') {
-            my %domdefaults = &Apache::lonnet::get_domain_defaults($cdom);
-            if ($domdefaults{'timezone_def'} ne '') {
-                $timezone = $domdefaults{'timezone_def'};
+    my ($timezone) = @_;
+    if ($timezone ne '') {
+        if (!DateTime::TimeZone->is_valid_name($timezone)) {
+            $timezone = 'local';
+        }
+        return $timezone;
+    }
+    my $cid = $Apache::lonnet::env{'request.course.id'};  
+    if ($cid ne '') {
+        if ($Apache::lonnet::env{'course.'.$cid.'.timezone'}) {
+            $timezone = $Apache::lonnet::env{'course.'.$cid.'.timezone'};    
+        } else {
+            my $cdom = $Apache::lonnet::env{'course.'.$cid.'.domain'};
+            if ($cdom ne '') {
+                my %domdefaults = &Apache::lonnet::get_domain_defaults($cdom);
+                if ($domdefaults{'timezone_def'} ne '') {
+                    $timezone = $domdefaults{'timezone_def'};
+                }
             }
         }
     } elsif ($Apache::lonnet::env{'request.role.domain'} ne '') {
@@ -322,8 +393,11 @@ sub gettimezone {
     return 'local';
 }
 
+our $timezone_local;
+
 sub locallocaltime {
-    my $thistime=shift;
+    my ($thistime,$timezone,$datetime) = @_;
+
     if (!defined($thistime) || $thistime eq '') {
 	return &mt('Never');
     }
@@ -336,8 +410,70 @@ sub locallocaltime {
         return &mt('Never');
     }
 
-    my $dt = DateTime->from_epoch(epoch => $thistime)
-                     ->set_time_zone(&gettimezone());
+   my $dt;
+   my $convert_time;
+
+   #### START # Speed up if this function is called often #### 
+   
+   # Is a $datetime parameter set?
+   if(defined($datetime)) {
+	# Check for an instance of a DateTime object
+   	if(!(defined $$datetime)) {
+		# No object, create one
+		$$datetime = DateTime->from_epoch(epoch => $thistime)
+       	                  ->set_time_zone(&gettimezone($timezone));
+		$dt = $$datetime;
+	   } else {
+		# If the return-value is "local", we have to convert it for DateTime	
+	
+		# Converts the "local"-String only once
+		if(!defined($timezone_local))	
+		{
+			$timezone_local = DateTime::TimeZone->new( name => gettimezone('local'))->name();
+		}
+
+		my $timezone_now;
+
+		if(gettimezone($timezone) == 'local')
+		{
+			$timezone_now = $timezone_local;
+		} else {
+			$timezone_now = gettimezone($timezone);
+		}
+
+		# Has the timezone changed?
+		if($timezone_now eq $$datetime->time_zone_short_name() ||
+		   $timezone_now eq $$datetime->time_zone_long_name())
+		{
+			# There is already an object (dereference)
+			$dt = $$datetime;
+		
+			# We need this as temporary value	
+			$convert_time = DateTime->from_epoch( epoch => $thistime );
+        	                                #->set_time_zone('floating');
+ 
+			# Preventing a set_time_zone call (time consuming)	
+			# Using old instance of DateTime with timezone
+			$dt->set( year => $convert_time->year(),
+				  month => $convert_time->month(),
+				  day => $convert_time->day(),
+				  hour => $convert_time->hour(),
+				  minute => $convert_time->minute(),
+				  second => $convert_time->second() );
+   		} else {
+			# The timezone has changed since last time
+			$$datetime = DateTime->from_epoch(epoch => $thistime)
+                          ->set_time_zone(&gettimezone($timezone));
+			$dt = $$datetime;
+		} 
+	}
+   } else {
+	# There is no $datetime parameter
+	$dt = DateTime->from_epoch(epoch => $thistime)
+                      ->set_time_zone(&gettimezone($timezone));
+   }
+   #### END # Speed up if this function is called often ####
+
     if ((&current_language=~/^en/) || (!$lh)) {
 
 	return $dt->strftime("%a %b %e %I:%M:%S %P %Y (%Z)");
@@ -410,13 +546,19 @@ sub getdatelocale {
     return $locale_obj;
 }
 
+=pod 
 
-# ==================== Normalize string (reduce fragility in the lexicon files)
+=item * normalize_string
+
+Normalize string (reduce fragility in the lexicon files)
+
+This normalizes a string to reduce fragility in the lexicon files of
+huge messages (such as are used by the helper), and allow useful
+formatting: reduce all consecutive whitespace to a single space,
+and remove all HTML
+
+=cut
 
-# This normalizes a string to reduce fragility in the lexicon files of
-# huge messages (such as are used by the helper), and allow useful
-# formatting: reduce all consecutive whitespace to a single space,
-# and remove all HTML
 sub normalize_string {
     my $s = shift;
     $s =~ s/\s+/ /g;
@@ -427,13 +569,27 @@ sub normalize_string {
     return $s;
 }
 
-# alias for normalize_string; recommend using it only in the lexicon
+=pod 
+
+=item * ns
+
+alias for normalize_string; recommend using it only in the lexicon
+
+=cut
+
 sub ns {
     return normalize_string(@_);
 }
 
-# mtn: call the mt function and the normalization function easily.
-# Returns original non-normalized string if there was no translation
+=pod
+
+=item * mtn
+
+mtn: call the mt function and the normalization function easily.
+Returns original non-normalized string if there was no translation
+
+=cut
+
 sub mtn (@) {
     my @args = @_; # don't want to modify caller's string; if we
 		   # didn't care about that we could set $_[0]