Bug 31775: Show single library

Test plan:
Check both cases: one library (public accessible) and more
libraries (public accessible). In the latter case click on
one of these libraries too.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>

Signed-off-by: David Nind <david@davidnind.com>

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>

opac/opac-library.pl

@@ -21,6 +21,7 @@ use Modern::Perl;
 
 use CGI qw ( -utf8 );
 use C4::Auth qw( get_template_and_user );
+use C4::Context;
 use C4::Output qw( output_html_with_http_headers );
 use Koha::Libraries;
 
@@ -37,21 +38,20 @@ my ( $template, $borrowernumber, $cookie ) = get_template_and_user(
     }
 );
 
-my $found;
-if ($branchcode) {
-    my $library = Koha::Libraries->find($branchcode);
-    if ( $library && $library->public ) {
-        $found++;
-        $template->param( library => $library );
-    }
+my $library;
+if( $template->{VARS}->{singleBranchMode} ) {
+    $library = Koha::Libraries->search({ public => 1 })->next;
+} elsif( $branchcode ) {
+    $library = Koha::Libraries->search({ branchcode => $branchcode, public => 1 })->next;
 }
 
-unless ($found) {
+if( $library ) {
+    $template->param( library => $library );
+} else {
     my $libraries = Koha::Libraries->search( { public => 1 }, { order_by => ['branchname'] } );
-
     $template->param(
         libraries  => $libraries,
-        branchcode => $branchcode,
+        branchcode => C4::Context->userenv ? C4::Context->userenv->{branch} : q{},
     );
 }