#! perl

#
# problems with this implementation include
# 
# - primary, secondary, tertiary are NO different to other hilighting styles
# - if rend values are missing, they are not being interpolated
#

my $SIZEOF_LONG = length pack "l!", 0;

sub refresh {
   my ($self) = @_;

   delete $self->{overlay};

   my $text = $self->{text};

   return unless length $text;

   my ($row, $col) = $self->screen_cur;

   my $idx = 0;

   my @rend = map {
      my $rstyle = $self->{caret} == $idx ? urxvt::OVERLAY_RSTYLE : $self->rstyle;

      $rstyle |= urxvt::RS_Uline   if $_ & (urxvt::XIMUnderline | urxvt::XIMPrimary);
      $rstyle |= urxvt::RS_RVid    if $_ & (urxvt::XIMReverse   | urxvt::XIMSecondary);
      $rstyle |= urxvt::RS_Italic  if $_ & (urxvt::XIMHighlight | urxvt::XIMTertiary);

      ($rstyle) x ($self->strwidth (substr $text, $idx++, 1))
   } unpack "l!*", $self->{rend};

   if ($self->{caret} >= length $text) {
      $text .= " ";
      push @rend, urxvt::OVERLAY_RSTYLE;
   }

   $self->{overlay} = $self->overlay ($col, $row, $self->strwidth ($text), 1, $self->rstyle, 0);
   $self->{overlay}->set (0, 0, $self->special_encode ($text), \@rend);
}

sub on_xim_preedit_start {
   my ($self) = @_;

   ()
}

sub on_xim_preedit_done {
   my ($self) = @_;

   delete $self->{overlay};
   delete $self->{text};
   delete $self->{rend};

   ()
}

sub on_xim_preedit_draw {
   my ($self, $caret, $pos, $len, $feedback, $chars) = @_;

   $self->{caret} = $caret;

   substr $self->{rend}, $pos * $SIZEOF_LONG, $len * $SIZEOF_LONG, $feedback;
   substr $self->{text}, $pos               , $len               , $chars if defined $feedback || !defined $chars;

   $self->refresh;

   ()
}