Create etherpad group when joining, not creating the room

So it's created for pre-existing rooms

public/vroom.pl

@@ -200,15 +200,6 @@ helper create_room => sub {
   my $tp = $self->get_random(49);
   $sth->execute($name,time(),time(),$owner,$tp,$config->{realm}) || return undef;
   $self->app->log->info("Room $name created by " . $self->session('name'));
-  # therpad integration ?
-  if ($ec){
-    my $group = $ec->create_group() || undef;
-    return undef unless ($group);
-    $sth = eval { $self->db->prepare("UPDATE `rooms` SET `etherpad_group`=? WHERE `name`='$name';") } || return undef;
-    $sth->execute($group);
-    $ec->create_group_pad($group,$name) || return undef;
-    $self->app->log->debug("Etherpad group $group created for room $name");
-  }
   return 1;
 };
 
@@ -859,6 +850,15 @@ get '/(*room)' => sub {
   $self->session($room => {role => 'participant'}) if (!$self->session($room) || !$self->session($room)->{role});
   # Create etherpad session if needed
   if ($ec && !$self->session($room)->{etherpadSession}){
+    # pad doesn't exist yet ?
+    if (!$data->{etherpad_group}){
+      my $group = $ec->create_group() || undef;
+      return undef unless ($group);
+      my $sth = eval { $self->db->prepare("UPDATE `rooms` SET `etherpad_group`=? WHERE `name`='$room';") } || return undef;
+      $sth->execute($group);
+      $ec->create_group_pad($group,$room) || return undef;
+      $self->app->log->debug("Etherpad group $group created for room $room");
+    }
     my $id = $ec->create_author_if_not_exists_for($self->session('name'));
     $self->session($room)->{etherpadAuthorId} = $id;
     my $etherpadSession = $ec->create_session($data->{etherpad_group}, $id, time + 86400);