i18n.pl

        # Reimplement "url_for" helper
        my $mojo_url_for = *Mojolicious::Controller::url_for{CODE};

        my $i18n_url_for = sub {
                my $self = shift;
                my $url  = $self->$mojo_url_for(@_);

                # Absolute URL
                return $url if $url->is_abs;

                # discard target if any
                shift if @_ && (!(@_ % 2) || !ref $_[0]);
                
                # unwrap params
                my %params = @_ == 1 ? %{$_[-1]} : @_;

                # Detect lang
                if (my $lang = $params{lang} || $self->stash('lang')) {
                        my $path = $url->path || [];

                        # Root
                        if (!$path->[0]) {
                                $path->parts([ $lang ]);
                        }

                        # No language detected
                        elsif ( ref $langs ne 'ARRAY' or not scalar grep { $path->contains("/$_") } @$langs ) {
                                unshift @{ $path->parts }, $lang;
                        }
                }

                return $url;
        };