#! perl

# this extension implements scrollback buffer search

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

   my $hotkey = $self->{argv}[0]
                || $self->x_resource ("searchable-scrollback")
                || "M-s";

   $self->parse_keysym ($hotkey, "perl:searchable-scrollback:start")
      or warn "unable to register '$hotkey' as scrollback search start hotkey\n";

   ()
}

sub on_keyboard_command {
   my ($self, $cmd) = @_;

   $cmd eq "searchable-scrollback:start"
      and $self->enter;

   ()
}

sub msg {
   my ($self, $msg) = @_;

   $self->{overlay} = $self->overlay (0, -1, $self->ncol, 1, urxvt::OVERLAY_RSTYLE, 0);
   $self->{overlay}->set (0, 0, $self->special_encode ($msg));
}

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

   return if $self->{overlay};

   $self->{view_start} = $self->view_start;
   $self->{pty_ev_events} = $self->pty_ev_events (urxvt::EVENT_NONE);
   $self->{row} = $self->nrow - 1;

   $self->enable (
      key_press     => \&key_press,
      tt_write      => \&tt_write,
      refresh_begin => \&refresh,
      refresh_end   => \&refresh,
   );

   $self->{manpage_overlay} = $self->overlay (0, -2, $self->ncol, 1, urxvt::OVERLAY_RSTYLE, 0);
   $self->{manpage_overlay}->set (0, 0, "scrollback search, see the ${urxvt::RXVTNAME}perl manpage for details");

   $self->idle;
}

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

   $self->disable ("key_press", "tt_write", "refresh_begin", "refresh_end");
   $self->pty_ev_events ($self->{pty_ev_events});

   delete $self->{manpage_overlay};
   delete $self->{overlay};
   delete $self->{history};
   delete $self->{search};
}

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

   $self->msg ("(escape cancels) /$self->{search}█");
}

sub search {
   my ($self, $dir) = @_;

   delete $self->{found};
   my $row = $self->{row};

   my $search = $self->special_encode ($self->{search});

   no re 'eval'; # just to be sure
   if (my $re = eval { qr/$search/ }) {
      while ($self->nrow > $row && $row > $self->top_row) {
         my $line = $self->line ($row)
            or last;

         my $text = $line->t;
         if ($text =~ /$re/g) {
            do {
               push @{ $self->{found} }, [$line->coord_of ($-[0]), $line->coord_of ($+[0])];
            } while $text =~ /$re/g;

            $self->{row} = $row;
            $self->view_start (List::Util::min 0, $row - ($self->nrow >> 1));
            $self->want_refresh;
            last;
         }

         $row = $dir < 0 ? $line->beg - 1 : $line->end + 1;
      }
   }

   $self->scr_bell unless $self->{found};
}

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

   return unless $self->{found};

   my $xor = urxvt::RS_RVid | urxvt::RS_Blink;
   for (@{ $self->{found} }) {
      $self->scr_xor_span (@$_, $xor);
      $xor = urxvt::RS_RVid;
   }

   ()
}

sub key_press {
   my ($self, $event, $keysym, $string) =  @_;

   delete $self->{manpage_overlay};

   if ($keysym == 0xff0d || $keysym == 0xff8d) { # enter
      if ($self->{found}) {
         my ($br, $bc, $er, $ec) = @{ $self->{found}[0] };
         $self->selection_beg ($br, $bc);
         $self->selection_end ($er, $ec);
         $self->selection_make ($event->{time});
      }
      $self->leave;
   } elsif ($keysym == 0xff1b) { # escape
      $self->view_start ($self->{view_start});
      $self->leave;
   } elsif ($keysym == 0xff57) { # end
      $self->{row} = $self->nrow - 1;
      $self->view_start (0);
   } elsif ($keysym == 0xff52) { # up
      $self->{row}-- if $self->{row} > $self->top_row;
      $self->search (-1);
   } elsif ($keysym == 0xff54) { # down
      $self->{row}++ if $self->{row} < $self->nrow;
      $self->search (+1);
   } elsif ($keysym == 0xff08) { # backspace
      substr $self->{search}, -1, 1, "";
      $self->search;
      $self->idle;
   } elsif ($string !~ /[\x00-\x1f\x80-\xaf]/) {
      return; # pass to tt_write
   }

   1
}

sub tt_write {
   my ($self, $data) = @_;

   $self->{search} .= $self->locale_decode ($data);
   $self->search (-1);
   $self->idle;

   1
}