Add localization support.

Right now, only two languages are supported, and only a fraction of strings
are already translated. There's also quite a bunch of todos left where
strings are assembled in the Model, which has no access to localization
functions. But that's something for iterative refinement over the next
months, and (especially when it comes to adding languages and translation
strings to templates) merge requests.

Squashed commit of the following:

commit 67d756f3bd167003907c8357126630dd7c1a3cfa
Author: Birte Kristina Friesel <derf@finalrewind.org>
Date:   Fri Jul 18 19:53:56 2025 +0200

    more translations

commit 8cb0d65e70e42180419a5dd7634d332e65488dd4
Author: Birte Kristina Friesel <derf@finalrewind.org>
Date:   Fri Jul 18 18:54:12 2025 +0200

    sme more translations

commit ff12f010380914f9461966f2ef8ac6b303712ee4
Author: Birte Kristina Friesel <derf@finalrewind.org>
Date:   Fri Jul 18 18:53:31 2025 +0200

    Add language selection to account page

commit 9bf27132cbf2f87bca5af564914d96a57045ecc1
Author: Birte Kristina Friesel <derf@finalrewind.org>
Date:   Fri Jul 18 16:42:28 2025 +0200

    Translate footer components

commit 90c2c6505e933848268ed9c5bbe21e0b459cd72a
Author: Birte Kristina Friesel <derf@finalrewind.org>
Date:   Fri Jul 18 16:16:50 2025 +0200

    Use Accept-Language header if user has no preferred languages

commit 814cb4a4dd4017606829ecc6b6c70822bf52a30e
Author: Birte Kristina Friesel <derf@finalrewind.org>
Date:   Fri Jul 18 16:11:19 2025 +0200

    Add list of preferred languages to user settings

commit 731b789855914cb94ec091604e32aa68a678404a
Author: Birte Kristina Friesel <derf@finalrewind.org>
Date:   Fri Jul 18 15:33:42 2025 +0200

    Localization with Locale::Maketext

    WiP, no suitable foundation for merge requests yet.

    Still todo:
    * override Accept-Language header via account settings
    * Adjust all the templates and frontend javascript

    Related to #223

6 files changed, 134 insertions, 5 deletions

diff --git a/lib/Travelynx.pm b/lib/Travelynx.pm
index 7dba658..33a8328 100755
--- a/lib/Travelynx.pm
+++ b/lib/Travelynx.pm
@@ -26,6 +26,7 @@ use Travelynx::Helper::DBRIS;
 use Travelynx::Helper::EFA;
 use Travelynx::Helper::HAFAS;
 use Travelynx::Helper::IRIS;
+use Travelynx::Helper::Locales;
 use Travelynx::Helper::MOTIS;
 use Travelynx::Helper::Sendmail;
 use Travelynx::Helper::Traewelling;
@@ -157,6 +158,14 @@ sub startup {
 		}
 	);
 
+	$self->hook(
+		'before_render' => sub {
+			my ($self) = @_;
+
+			$self->stash( loc_handle => $self->loc_handle );
+		}
+	);
+
 	$self->attr(
 		cache_iris_main => sub {
 			my ($self) = @_;
@@ -412,6 +421,40 @@ sub startup {
 	);
 
 	$self->helper(
+		loc_handle => sub {
+			my ($self) = @_;
+
+			my @languages;
+			if ( $self->is_user_authenticated
+				and @{ $self->current_user->{languages} } )
+			{
+				@languages = @{ $self->current_user->{languages} };
+			}
+			elsif ( my $languages = $self->req->headers->accept_language ) {
+				for my $lang ( split( qr{ \s* , \s* }x, $languages ) ) {
+					if ( $lang =~ m{ ^ de }x ) {
+						push( @languages, 'de-DE' );
+					}
+					elsif ( $lang =~ m{ ^ en }x ) {
+						push( @languages, 'en-GB' );
+					}
+				}
+			}
+
+			# de-DE is our fall-back language and thus always appended
+			return Travelynx::Helper::Locales->get_handle( @languages,
+				'de-DE' );
+		}
+	);
+
+	$self->helper(
+		'L' => sub {
+			my ( $self, @args ) = @_;
+			$self->stash('loc_handle')->maketext(@args);
+		}
+	);
+
+	$self->helper(
 		'now' => sub {
 			return DateTime->now( time_zone => 'Europe/Berlin' );
 		}
@@ -3067,6 +3110,7 @@ sub startup {
 	$authed_r->get('/account/hooks')->to('account#webhook');
 	$authed_r->get('/account/traewelling')->to('traewelling#settings');
 	$authed_r->get('/account/insight')->to('account#insight');
+	$authed_r->get('/account/language')->to('account#change_language');
 	$authed_r->get('/ajax/status_card.html')->to('traveling#status_card');
 	$authed_r->get( '/cancelled' => [ format => [ 'html', 'json' ] ] )
 	  ->to( 'traveling#cancelled', format => undef );
@@ -3097,6 +3141,7 @@ sub startup {
 	$authed_r->post('/account/hooks')->to('account#webhook');
 	$authed_r->post('/account/traewelling')->to('traewelling#settings');
 	$authed_r->post('/account/insight')->to('account#insight');
+	$authed_r->post('/account/language')->to('account#change_language');
 	$authed_r->post('/account/select_backend')->to('account#change_backend');
 	$authed_r->post('/checkin/add')->to('traveling#add_intransit_form');
 	$authed_r->post('/journey/add')->to('traveling#add_journey_form');
diff --git a/lib/Travelynx/Command/database.pm b/lib/Travelynx/Command/database.pm
index 34efde6..009da30 100644
--- a/lib/Travelynx/Command/database.pm
+++ b/lib/Travelynx/Command/database.pm
@@ -3359,6 +3359,28 @@ qq{select distinct checkout_station_id from in_transit where backend_id = 0;}
 			}
 		);
 	},
+
+	# v66 -> v67
+	# Add language settings to profile
+	sub {
+		my ($db) = @_;
+		$db->query(
+			qq{
+				drop view users_with_backend;
+				alter table users add column language varchar(128);
+				update schema_version set version = 67;
+				create view users_with_backend as select
+					users.id as id, users.name as name, status, public_level,
+					language, email, password, registered_at, last_seen,
+					deletion_requested, deletion_notified, use_history,
+					accept_follows, notifications, profile, backend_id, iris,
+					hafas, efa, dbris, motis, backend.name as backend_name
+					from users
+					left join backends as backend on users.backend_id = backend.id
+					;
+			}
+		);
+	},
 );
 
 sub sync_stations {
diff --git a/lib/Travelynx/Controller/Account.pm b/lib/Travelynx/Controller/Account.pm
index bf1eac2..8121f0a 100644
--- a/lib/Travelynx/Controller/Account.pm
+++ b/lib/Travelynx/Controller/Account.pm
@@ -874,6 +874,35 @@ sub webhook {
 	$self->render( 'webhooks', hook => $hook );
 }
 
+sub change_language {
+	my ($self) = @_;
+
+	my $action   = $self->req->param('action');
+	my $language = $self->req->param('language');
+
+	if ( $action and $action eq 'save' ) {
+		if ( $self->validation->csrf_protect->has_error('csrf_token') ) {
+			$self->render(
+				'bad_request',
+				csrf   => 1,
+				status => 400
+			);
+			return;
+		}
+		$self->users->set_language(
+			uid      => $self->current_user->{id},
+			language => $language,
+		);
+		$self->flash( success => 'language' );
+		$self->redirect_to('account');
+	}
+	else {
+		my @languages = @{ $self->current_user->{languages} };
+		$self->param( language => $languages[0] // q{} );
+		$self->render('language');
+	}
+}
+
 sub change_mail {
 	my ($self) = @_;
 
diff --git a/lib/Travelynx/Helper/Locales.pm b/lib/Travelynx/Helper/Locales.pm
new file mode 100644
index 0000000..12e95d1
--- /dev/null
+++ b/lib/Travelynx/Helper/Locales.pm
@@ -0,0 +1,22 @@
+package Travelynx::Helper::Locales;
+
+use strict;
+use warnings;
+
+use base qw(Locale::Maketext);
+
+our %lexicon = (
+	_AUTO => 1,
+);
+
+use Locale::Maketext::Lexicon {
+	_decode => 1,
+	'*'     => [ Gettext => 'share/locales/*.po' ],
+};
+
+sub init {
+	my ($self) = @_;
+	return $self->SUPER::init( @_[ 1 .. $#_ ] );
+}
+
+1;
diff --git a/lib/Travelynx/Model/Journeys.pm b/lib/Travelynx/Model/Journeys.pm
index b07511a..5e6195f 100755
--- a/lib/Travelynx/Model/Journeys.pm
+++ b/lib/Travelynx/Model/Journeys.pm
@@ -50,6 +50,8 @@ sub epoch_to_dt {
 	);
 }
 
+# TODO turn into a travelynx helper called from templates so that
+# loc_handle is available for localization
 sub min_to_human {
 	my ( $self, $minutes ) = @_;
 
diff --git a/lib/Travelynx/Model/Users.pm b/lib/Travelynx/Model/Users.pm
index be9e80b..3ef7f33 100644
--- a/lib/Travelynx/Model/Users.pm
+++ b/lib/Travelynx/Model/Users.pm
@@ -216,6 +216,14 @@ sub set_backend {
 	);
 }
 
+sub set_language {
+	my ( $self, %opt ) = @_;
+	$opt{db} //= $self->{pg}->db;
+
+	$opt{db}
+	  ->update( 'users', { language => $opt{language} }, { id => $opt{uid} } );
+}
+
 sub set_privacy {
 	my ( $self, %opt ) = @_;
 	my $db           = $opt{db} // $self->{pg}->db;
@@ -413,7 +421,7 @@ sub get {
 
 	my $user = $db->select(
 		'users_with_backend',
-		'id, name, status, public_level, email, '
+		'id, name, status, public_level, email, language, '
 		  . 'accept_follows, notifications, '
 		  . 'extract(epoch from registered_at) as registered_at_ts, '
 		  . 'extract(epoch from last_seen) as last_seen_ts, '
@@ -423,10 +431,11 @@ sub get {
 	)->hash;
 	if ($user) {
 		return {
-			id                     => $user->{id},
-			name                   => $user->{name},
-			status                 => $user->{status},
-			notifications          => $user->{notifications},
+			id            => $user->{id},
+			name          => $user->{name},
+			languages     => [ split( qr{[|]}, $user->{language} // q{} ) ],
+			status        => $user->{status},
+			notifications => $user->{notifications},
 			accept_follows         => $user->{accept_follows} == 2 ? 1 : 0,
 			accept_follow_requests => $user->{accept_follows} == 1 ? 1 : 0,
 			default_visibility     => $user->{public_level} & 0x7f,