#! perl
# TabbedEx plugin for rxvt-unicode; based on original tabbed plugin.
# https://github.com/mina86/urxvt-tabbedex
# Copyright (c) 2006-2016 tabbed and tabbedex authors
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

=head1 NAME

tabbedex - tabbed interface to urxvt; extended

=head1 DESCRIPTION

This transforms the terminal into a tabbar with additional terminals, that is,
it implements what is commonly referred to as "tabbed terminal".  tabbedex is an
extended version of the tabbed plugin which comes with urxvt.

When rxvt-unicode is started with this plugin slave terminals or tabs can be
started and switched between.  One of the terminals is the current or active one
and it is the only one that is visible.  rxvt-unicode will exit once all tabs
are closed.

Once at least two slave terminals are created a tab bar is displayed at the top
of the window which lists all the slave terminals.  Clicking on a number/name of
a tab on that bar switches to given tab.

=head2 Key bindings

Creating new tabs, switching between them and moving them around is accomblished
by the following key bindings:

=over

=item B<Shift-Down>

Creates a new tab.

=item B<Shift-Left> and B<Shift-Right>

Switches to the tab on the left or on the right of the current tab.  Movement
wraps around once at the first or last tab.

=item B<Meta-F1> through B<Meta-F12>

Switches to the first through twelfth tab.

=item B<Control-Left> and B<Control-right>

Move current tab to the left or right.  Wraps around once on the first/last
position.

=item B<Shift-Up>

Allows current tab to be renamed.  Start typing desired new name and press
Return to confirm or Escape to cancel.

=back

=head1 CONFIGURATION

The extension can be configured similarly to a normal terminal.  By default, it
uses a resource class of C<URxvt.tabbed> which is the same as the tabbed
extension.

=over

=item B<autohide>: I<boolean>

If set (the default), the tab bar will be hidden unless there are at least two
tabs open.  This is irrespective of whether C<NEW> button or tab's title is
displayed.

=item B<bell-fg>: I<colour index>

=item B<bell-bg>: I<colour index>

Foreground and background colours of an inactive tab on which bell has rung.
(0, 3) by default which translates to black on brown/dark yellow (i.e. inverse
of the default tab bar colours).  See I<COLOUR AND GRAPHICS> in the L<urxvt(1)>
manpage for valid indices.

=item B<bell-tab-fg>: I<colour index>

=item B<bell-tab-bg>: I<colour index>

Foreground and background colours of a active tab in which bell is ringing.  (5,
4) by default which translates to magenta an blue.  See I<COLOUR AND GRAPHICS>
in the L<urxvt(1)> manpage for valid indices.  The bell is said to be ringing on
an active tab for B<bell-timeout> seconds after it started, see B<bell-timeout>.

=item B<bell-timeout>: I<integer>

Time in seconds, one second by default, a bell is said to be ringing on current
tab for after it was rung.  Setting this to zero essentially disables the
B<bell-tab-(fg|bg)> styling of tabs.

=item B<new-button>: I<boolean>

If set, a C<NEW> button will be displayed on the left of the tab bar.  Clicking
the button creates a new tab.  It is not displayed by default.

=item B<new-tab-command>: I<string>

Specifies how urxvt's B<-e> switch affects tabs created by tabbedex.  The
resource can have one of three values:

=over

=item I<inherit>

The default.  The B<-e> command will be used by all tabs created by tabbedex.

=item I<clear>

Only the initial tab will use the B<-e> switch provided on urxvt's command line.
All other tabs will act as if the option was not provided.

=item I<-e B<another command>>

The initial tab will use the B<-e> switch provided on urxvt's command line (if
any) while all other tabs will use switch specified by this setting.  Note that
parsing of the resource simply splits words on white space so things like I<-e
my-prog "argument with spaces"> will not work.

=back

=item B<no-tabbedex-keys>: I<boolean>

If set, the default key bindings (described at the beginning of this document)
are not initialised.  The mappings can be recreated using urxvt's support of
a keysym.* resource.  For example, the following will recreate all the default
key bindings:

    URxvt.tabbed.no-tabbedex-keys: yes
    URxvt.keysym.Shift-Left: perl:tabbedex:prev_tab
    URxvt.keysym.Shift-Right: perl:tabbedex:next_tab
    URxvt.keysym.Shift-Down: perl:tabbedex:new_tab
    URxvt.keysym.Shift-Up: perl:tabbedex:rename_tab
    URxvt.keysym.Control-Left: perl:tabbedex:move_tab_left
    URxvt.keysym.Control-Right: perl:tabbedex:move_tab_right
    URxvt.keysym.Meta-F1: perl:tabbedex:goto_tab_1
    URxvt.keysym.Meta-F2: perl:tabbedex:goto_tab_2
    URxvt.keysym.Meta-F3: perl:tabbedex:goto_tab_3
    URxvt.keysym.Meta-F4: perl:tabbedex:goto_tab_4
    URxvt.keysym.Meta-F5: perl:tabbedex:goto_tab_5
    URxvt.keysym.Meta-F6: perl:tabbedex:goto_tab_6
    URxvt.keysym.Meta-F7: perl:tabbedex:goto_tab_7
    URxvt.keysym.Meta-F8: perl:tabbedex:goto_tab_8
    URxvt.keysym.Meta-F9: perl:tabbedex:goto_tab_9
    URxvt.keysym.Meta-F10: perl:tabbedex:goto_tab_10
    URxvt.keysym.Meta-F11: perl:tabbedex:goto_tab_11
    URxvt.keysym.Meta-F12: perl:tabbedex:goto_tab_12

=item B<perl-ext-blacklist>: I<string>

A comma-separated list of extensions that must not be loaded into the slave
terminals (tabs).  tabbedex plugin is implicitly added onto the list.

=item B<reopen-on-close>: I<boolean>

If set, whenever last tab is destroyed a new one will be created.

=item B<tabbar-fg>: I<color index>

=item B<tabbar-bg>: I<color index>

Foreground and background colours of the tab bar.  (3, 0) by default which
translates to brown/dark yellow on black background.  See I<COLOUR AND GRAPHICS>
in the L<urxvt(1)> manpage for valid indices.

=item B<tab-fg>: I<color index>

=item B<tab-bg>: I<color index>

Foreground and background colours of the current tab on the tab bar.  (0, 1) by
default which translates to black on red.  See I<COLOUR AND GRAPHICS> in the
L<urxvt(1)> manpage for valid indices.

=item B<tabbar-timeouts>: I<string>

When new text is written to an inactive tab, activity marks are displayed around
its number (or name if it has one) on the tab bar.  By default Unicode
characters are used to display a block which grows with time the longer it was
since last time there was any activity in the tab.

This resource allows for this to be customised.  It's format is

    ( <timeout> ":" <character> ":" )* <timeout> ":" <character> ":"

where <timeout> is timeout in seconds and <character> is a single activity
character.  If activity character is (, [, { or < it will be used as left
activity mark and matching character will be used on the right side.

=item B<tabbedex-rs-prefix>: I<string>

By default tabbedex uses the same prefix for resource names as tabbed plugin.
If this is not desired, the resource can be used to set a new prefix, for
example:

    URxvt.tabbed.tabbedex-rs-prefix: tabbedex

    ! Affects tabbed only:
    URxvt.tabbed.tabbar-fg: 4
    URxvt.tabbed.tabbar-bg: 0

    ! Affects tabbedex only:
    URxvt.tabbed.tabbar-fg: 5
    URxvt.tabbed.tabbar-bg: 0

This settings does not affect the B<tabbedex-rs-prefix> resource itself which is
always read from C<URxvt.tabbed.tabbedex-rs-prefix>.

=item B<title>: I<boolean>

If set (the default), when tab bar is visible and there is enough space left,
current tab's title will be displayed after the last tab.

=item B<title-fg>: I<color inde>

=item B<title-bg>: I<color inde>

Foreground and background colours of the tab title.  (2, 0) by default which
translates to green on black.  Only used when B<title> is true.  See I<COLOUR
AND GRAPHICS> in the L<urxvt(1)> manpage for valid indices.

=back

=head1 USER COMMANDS

tabbedex supports several user commands which can be used with
B<URxvt.keysym>.I<keysym> resource as well as other places.  The commands are:

=over

=item B<tabbedex:new_tab>

Creates a new tab.

=item B<tabbedex:next_tab> and B<tabbedex:prev_tab>

Switches to the tab on the right or left of the current tab.

=item B<tabbedex:move_tab_left> and B<tabbedex:move_tab_right>

Moves the current tab left or right.

=item B<goto_tab_>I<N> where I<N> is positive integer

Switches to the tab given by the number I<N>

=item B<tabbedex:kill_tab>

Kills/destroys current tab.

=back

=head1 OSC SEQUENCES

tabbedex supports a single OSC sequence which can be invoked by programs running
in the terminal by writing a special sequence, namely I<ESC ] 777 ; string ST>
where I<string> is the command to execute.  For example:

    printf '\033]777;tabbedx;set_tab_name;%s\007' "foo"

=over

=item B<tabbedex;set_tab_name;>I<name>

Sets name of the current tab to I<name>.

=back

=cut

use Encode qw(decode);

sub update_autohide {
   my ($self, $reconfigure) = @_;
   my $oldh = $self->{tabheight};
   if (!$self->{autohide} ||
       @{ $self->{tabs} } > 1 ||
       $self->{is_inputting_name}) {
      $self->{tabheight} = $self->{maxtabheight};
    } else {
      $self->{tabheight} = 0;
   }
   if ($reconfigure && $self->{tabheight} != $oldh) {
      $self->configure;
      $self->copy_properties;
   }
}


sub tab_bell_active ($$$) {
    my ($self, $tab, $now) = @_;
    if ($tab->{bell_rung}) {
        if ($tab == $self->{cur}) {
            return $now - $tab->{bell_rung} < $self->{bell_timeout};
        } else {
            return 1;
        }
    }
    return 0;
}

sub tab_activity_mark ($$;$) {
   my ($self, $tab, $now) = @_;
   return ' ' unless defined $tab->{last_activity};
   return ' ' if $tab == $self->{cur};
   $now = $now // int urxvt::NOW;
   if (defined $self->{timeouts}) {
      my $diff = $now - $tab->{last_activity};
      for my $spec (@{ $self->{timeouts} }) {
         return $spec->[1] if $diff >= $spec->[0];
      }
   }
   '*';
}

{

my %matching_activity_marks = (
    '[' => ']',
    '{' => '}',
    '(' => ')',
    '<' => '>',
);

sub matching_activity_mark {
    return $matching_activity_marks{$_[0]} // $_[0];
}

}


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

   # autohide makes it zero
   return unless $self->{tabheight};

   my $ncol = $self->ncol;

   my $text = " " x $ncol;
   my $rend = [($self->{rs_tabbar}) x $ncol];

   my ($ofs, $idx, @ofs) = (0, 0);

   if ($self->{new_button}) {
      substr $text, 0, 7, "[NEW] |";
      @$rend[0 .. 5] = ($self->{rs_tab}[1]) x 6;
      push @ofs, [0, 6, -1 ];
      $ofs = 7;
   }

   my $space_available = $ofs;
   my $max_len = int(($ncol - $ofs - 5) / ($#{ $self->{tabs} } > 1 ? 3 : 2));

   # See if the name of the current tab would be displayed;
   # if not, compute the number of tabs to skip so that the
   # name of the current tab will be displayed.
   my $len = $ofs;
   my @ends;
   for my $tab (@{ $self->{tabs} }) {
      my $name = $tab->tab_name($idx, $max_len);
      ++$idx;
      $len += length($name) + 3;        # '| ' and ' '
      if ($tab == $self->{cur}) {
         $idx = 0;
         if ($len > $ncol + 1) {
            for my $end (@ends) {
               ++$idx;
               if ($len - $end <= $ncol) {
                  last;
               }
            }
         }
         last;
      }
      push @ends, $len;
   }

   my $now = int urxvt::NOW;

   for (; $idx < @{ $self->{tabs} }; ++$idx) {
      my $tab = $self->{tabs}[$idx];
      my $name = $tab->tab_name($idx, $max_len);
      my $act = $self->tab_activity_mark($tab, $now);
      my $txt = sprintf "%s%s%s", $act, $name, matching_activity_mark $act;
      my $len = length $txt;

      substr $text, $ofs, $len + 1, "$txt|";

      my $color = $self->{rs_tab}[
         2 * $self->tab_bell_active($tab, $now) + ($tab == $self->{cur})
      ];
      if (defined $color) {
         @$rend[$ofs .. $ofs + $len - 1] = ($color) x $len;
      }

      push @ofs, [ $ofs, $ofs + $len, $idx ];
      $ofs += $len + 1;
   }

   substr $text, --$ofs, 1, ' '; # remove last '|'

   if ($self->{tab_title} && $ofs + 3 < $ncol) {
      my $term = $self->{term};
      my @str = $term->XGetWindowProperty($term->parent, $self->{tab_title});
      if (@str && $str[2]) {
         my $str = '| ' . decode("utf8", $str[2]);
         my $len = length $str;
         $len = $ncol - $ofs if $ofs + $len > $ncol;
         substr $text, $ofs, $len, substr $str, 0, $len;
         @$rend[$ofs + 2 .. $ofs + $len - 1] = ($self->{rs_title}) x ($len - 2);
      }
   }

   $self->{tabofs} = \@ofs;

   $self->ROW_t (0, $text, 0, 0, $ncol);
   $self->ROW_r (0, $rend, 0, 0, $ncol);

   $self->want_refresh;
}


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

   unless ($self->{autohide} &&
           !(defined $self->{tabs} && @{ $self->{tabs} })) {
      $self->{tabheight} = $self->{maxtabheight}
   }

   # save a backlink to us, make sure tabbedex is inactive
   push @urxvt::TERM_INIT, sub {
      my ($term) = @_;
      $term->{parent} = $self;

      for (0 .. urxvt::NUM_RESOURCES - 1) {
         my $value = $self->{resource}[$_];

         $term->resource ("+$_" => $value)
            if defined $value;
      }

      foreach my $opt (keys %urxvt::OPTION) {
          my $value = $self->{option}{$opt};
          $term->option($urxvt::OPTION{$opt}, $value);
      }

      $term->resource (perl_ext_2 =>
                       $term->resource ('perl_ext_2') .
                       $self->{perl_ext_blacklist});

      $self->register_keysyms($term);
   };

   push @urxvt::TERM_EXT, urxvt::ext::tabbedex::tab::;

   my $term = new urxvt::term
      $self->env, $urxvt::RXVTNAME,
      -embed => $self->parent,
      @{ $self->{argv} };
}


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

   my $tab = $self->{cur};

   # this is an extremely dirty way to force a configurenotify, but who cares
   $tab->XMoveResizeWindow (
      $tab->parent,
      0, $self->{tabheight} + 1,
      $self->width, $self->height - $self->{tabheight}
   );
   $tab->XMoveResizeWindow (
      $tab->parent,
      0, $self->{tabheight},
      $self->width, $self->height - $self->{tabheight}
   );
}


sub copy_properties {
   my ($self) = @_;
   my $tab = $self->{cur};

   my $wm_normal_hints = $self->XInternAtom ("WM_NORMAL_HINTS");

   my $current = delete $self->{current_properties};

   # pass 1: copy over properties different or nonexisting
   for my $atom ($tab->XListProperties ($tab->parent)) {
      my ($type, $format, $items) = $self->XGetWindowProperty ($tab->parent,
                                                               $atom);

      # fix up size hints
      if ($atom == $wm_normal_hints) {
         my (@hints) = unpack "l!*", $items;

         $hints[$_] += $self->{tabheight} for (4, 6, 16);

         $items = pack "l!*", @hints;
      }

      my $cur = delete $current->{$atom};

      # update if changed, we assume empty items and zero type and
      # format will not happen
      $self->XChangeProperty ($self->parent, $atom, $type, $format, $items)
         if $cur->[0] != $type or $cur->[1] != $format or $cur->[2] ne $items;

      $self->{current_properties}{$atom} = [$type, $format, $items];
   }

   # pass 2, delete all extraneous properties
   $self->XDeleteProperty ($self->parent, $_) for keys %$current;
}


sub rs_text {
    my ($self, $name, $default) = @_;
    my $value = $self->x_resource ($self->{rs_prefix} . '.' . $name);
    defined $value ? $self->locale_decode($value) : $default;
}

sub rs_bool {
    my ($self, $name, $default) = @_;
    my $val = $self->x_resource ($self->{rs_prefix} . '.' . $name);
    defined $val ? $val !~ /^(?:false|0|no)$/i : $default;
}

sub rs_color($$$$) {
    my ($self, $prefix, $def_fg, $def_bg) = @_;
    my $fg = $self->rs_text ($prefix . '-fg') // $def_fg;
    my $bg = $self->rs_text ($prefix . '-bg') // $def_bg;
    urxvt::SET_COLOR (urxvt::DEFAULT_RSTYLE, $fg + 2, $bg + 2);
}


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

    my $cur = $self->{cur};
    if ($cur != $tab) {
        if ($cur) {
            delete $cur->{last_activity};
            delete $cur->{bell_rung};
            $cur->XUnmapWindow ($cur->parent) if $cur->mapped;
            $cur->focus_out;
        }

        $self->{cur} = $tab;

        $self->configure;
        $self->copy_properties;

        $tab->focus_out; # just in case, should be a nop
        $tab->focus_in if $self->focus;

        $tab->XMapWindow ($tab->parent);
        delete $tab->{last_activity};
        delete $tab->{bell_rung};
    }
    $self->refresh;

    ();
}


sub on_focus_in {
   my ($self, $event) = @_;
   $self->{cur}->focus_in;
   ();
}

sub on_focus_out {
   my ($self, $event) = @_;
   $self->{cur}->focus_out;
   ();
}

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

    $self->{cur}->tt_write ($octets);

    1
}

sub on_key_press {
   my ($self, $event) = @_;
   $self->key_event('key_press', $event);
}

sub on_key_release {
   my ($self, $event) = @_;
   $self->key_event('key_release', $event);
}

sub key_event {
	my ($self, $type, $event) = @_;
	my $term = $self->{cur};
	$term->$type($event->{state}, $event->{keycode}, $event->{time});
	# refresh_check is available since rxvt-unicode 9.22.
	if ($term->can('refresh_check')) {
		$term->refresh_check;
	}
	1;
}

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

   if (!$self->{is_inputting_name} && $event->{row} == 0) {
      my $col = $event->{col};
      for my $button (@{ $self->{tabofs} }) {
         last if     $col <  $button->[0];
         next unless $col <= $button->[1];
         if ($button->[2] == -1) {
            $self->new_tab;
         } else {
            $self->make_current($self->{tabs}[$button->[2]]);
         }
      }
      return 1;
   }

   ();
}

sub register_keysyms {
    my ($self, $tab) = @_;
    if (!$self->{no_default_keys}) {
        $tab //= $self;
        $tab->parse_keysym('Shift-Left', 'perl:tabbedex:prev_tab');
        $tab->parse_keysym('Shift-Right', 'perl:tabbedex:next_tab');
        $tab->parse_keysym('Shift-Down', 'perl:tabbedex:new_tab');
        $tab->parse_keysym('Shift-Up', 'perl:tabbedex:rename_tab');
        $tab->parse_keysym('Control-Left', 'perl:tabbedex:move_tab_left');
        $tab->parse_keysym('Control-Right', 'perl:tabbedex:move_tab_right');
        for my $num (1..12) {
            $tab->parse_keysym('Meta-F' . $num,
                               'perl:tabbedex:goto_tab_' . $num);
        }
    }
}

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

   $self->{resource} = [map $self->resource ("+$_"),
                            0 .. urxvt::NUM_RESOURCES - 1];

   $self->resource (int_bwidth => 0);
   $self->resource (pty_fd => -1);

   $self->{rs_prefix} = 'tabbed';
   $self->{rs_prefix} = $self->rs_text ('tabbedex-rs-prefix', 'tabbed');

   $self->{option} = {};
   for my $key (keys %urxvt::OPTION) {
       $self->{option}{$key} = $self->option($urxvt::OPTION{$key});
   }

   # this is for the tabs terminal; order is important
   $self->option ($urxvt::OPTION{scrollBar}, 0);

   $self->{rs_tabbar} = $self->rs_color ('tabbar', 3, 0);
   $self->{rs_title}  = $self->rs_color ('title', 2, 0);
   $self->{rs_tab}    = [
      undef,                              # inactive
      $self->rs_color ('tab', 0, 1),      # active
      $self->rs_color ('bell', 0, 3),     # bell ringing
      $self->rs_color ('bell-tab', 5, 4)  # active, bell ringing
   ];

   my $timeouts = $self->rs_text('tabbar-timeouts',
                                 '0:▁:3:▂:6:▃:9:▄:12:▅:15:▆:18:▇:21:█');
   if ($timeouts) {
      my @timeouts;
      while ($timeouts =~ /^(\d+):(.)(?::(.*))?$/) {
         push @timeouts, [ int $1, $2 ];
         $timeouts = defined $3 ? $3 : '';
      }
      if (@timeouts) {
         $self->{timeouts} = [ sort { $b->[0] <=> $a-> [0] } @timeouts ];
      }
   }

   $self->{bell_timeout} = int($self->rs_text ('bell-timeout') // 1);

   $self->{new_button} = $self->rs_bool ('new-button', 0);
   $self->{tab_title} = $self->rs_bool ('title', 1);
   $self->{autohide} = $self->rs_bool ('autohide', 1);
   $self->{no_default_keys} = $self->rs_bool ('no-tabbedex-keys', 0);
   $self->{reopen_on_close} = $self->rs_bool ('reopen-on-close', 0);
   $self->{tab_urgent_on_bell} =
     $self->x_resource_boolean ('urgentOnBell') // 0;
   $self->{new_tab_command} = $self->rs_text ('new-tab-command', 'inherit');

   $self->register_keysyms;

   my @blacklist = split(',', $self->rs_text ('perl-ext-blacklist'));
   $self->{perl_ext_blacklist} = join (',-', ',-tabbedex', @blacklist);

   ();
}


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

   $self->{maxtabheight} =
      $self->int_bwidth + $self->fheight + $self->lineSpace;
   $self->{tabheight} = $self->{autohide} ? 0 : $self->{maxtabheight};

   $self->{running_user_command} = 0;

   $self->cmd_parse ("\033[?25l");

   my @argv = $self->argv;
   do {
      shift @argv;
   } while @argv && $argv[0] ne "-e";
   $self->{argv} = \@argv;

   if ($self->{tab_title}) {
      $self->{tab_title} = $self->{term}->XInternAtom("_NET_WM_NAME", 1);
   }

   $self->new_tab;

   if ($self->{new_tab_command} eq 'inherit') {
      # nop
   } elsif ($self->{new_tab_command} eq 'clear') {
      $self->{argv} = [];
   } elsif ($self->{new_tab_command} =~ /^-e\s/) {
      $self->{argv} = [split /\s+/, $self->{new_tab_command}];
   } else {
      printf "tabbedex: unrecognised value of new-tab-command: '%s'\n",
         $self->{new_tab_command};
   }
   delete $self->{new_tab_command};

   if (defined $self->{timeouts}) {
      my $interval = ($self->{timeouts}[@{ $self->{timeouts} } - 1]->[0]);
      $interval = int($interval / 4);
      $self->{timer} = urxvt::timer->new
                                   ->interval($interval < 1 ? 1 : $interval)
                                   ->cb ( sub { $self->refresh; } );
   }

   ();
}


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

   $self->configure;
   $self->refresh;

   ();
}


sub on_user_command {
    my $self = shift;
    $self->tab_user_command($self->{cur}, @_);
}


sub on_wm_delete_window {
   my ($self) = @_;
   $_->destroy for @{ $self->{tabs} };
   1;
}


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

   $tab->XChangeInput ($tab->parent, urxvt::PropertyChangeMask);

   push @{ $self->{tabs} }, $tab;

#   $tab->{name} ||= scalar @{ $self->{tabs} };
   $self->make_current ($tab);

   ();
}


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

   if ($self->{reopen_on_close} && $#{ $self->{tabs} } == 0) {
      $self->new_tab;
      $self->make_current ($self->{tabs}[-1]);
   }

   $self->{tabs} = [ grep $_ != $tab, @{ $self->{tabs} } ];
   $self->update_autohide ();

   if (@{ $self->{tabs} }) {
      if ($self->{cur} == $tab) {
         delete $self->{cur};
         $self->make_current ($self->{tabs}[-1]);
      } else {
         $self->refresh;
      }
   } else {
      # delay destruction a tiny bit
      $self->{destroy} = urxvt::iw->new->start->cb (sub { $self->destroy });
   }

   ();
}


sub tab_property_notify {
   my ($self, $tab, $event) = @_;

   $self->copy_properties
      if $event->{window} == $tab->parent;

   ();
}


sub tab_bell {
    my ($self, $tab, $event) = @_;
    my $now = int urxvt::NOW;
    my $bell = $self->tab_bell_active($tab, $now);
    $tab->{bell_rung} = $now;
    $self->refresh if $bell ne $self->tab_bell_active($tab, $now);
    if ($tab != $self->{cur} && $self->{tab_urgent_on_bell}) {
        $self->{term}->set_urgency(1);
    }
    ();
}


sub tab_add_lines {
    my ($self, $tab) = @_;
    my $now = int urxvt::NOW;
    my $mark = $self->tab_activity_mark($tab, $now);
    $tab->{last_activity} = $now;
    $self->refresh if $mark ne $self->tab_activity_mark($tab, $now);
    ();
}


sub tab_user_command {
  my ($self, $tab, $cmd, $proxy_events) = @_;

  if ($cmd eq 'tabbedex:new_tab') {
    if (!$self->{is_inputting_name}) {
      $self->new_tab;
    }
  }
  elsif ($cmd eq 'tabbedex:next_tab') {
    $self->change_tab($tab, 1);
  }
  elsif ($cmd eq 'tabbedex:prev_tab') {
    $self->change_tab($tab, -1);
  }
  elsif ($cmd eq 'tabbedex:move_tab_left') {
    $self->move_tab($tab, -1);
  }
  elsif ($cmd eq 'tabbedex:move_tab_right') {
    $self->move_tab($tab, 1);
  }
  elsif ($cmd =~ /^tabbedex:goto_tab_(\d+)$/) {
    $self->change_to_tab($tab, $1 - 1);
  }
  elsif ($cmd eq 'tabbedex:rename_tab') {
    $self->rename_tab($tab);
  }
  elsif ($cmd eq 'tabbedex:kill_tab') {
    $tab->destroy;
  }
  else {
    # Proxy the user command through to the tab's term, while taking care not
    # to get caught in an infinite loop.
    if ($proxy_events && $self->{running_user_command} == 0) {
      $self->{running_user_command} = 1;
      urxvt::invoke($tab->{term}, 20, $cmd);
      $self->{running_user_command} = 0;
    }
  }

  ();
}

sub change_tab {
    my ($self, $tab, $direction) = @_;

    if (!$self->{is_inputting_name} && @{ $self->{tabs} } > 1) {
        my $idx = 0;
        ++$idx while $self->{tabs}[$idx] != $tab;
        $idx += $direction;
        $self->make_current ($self->{tabs}[$idx % @{ $self->{tabs}}]);
    }

    ();
}

sub change_to_tab {
    my ($self, $tab, $idx) = @_;

    if (!$self->{is_inputting_name} && @{ $self->{tabs} } > 1 && $idx >= 0 && $idx < @{ $self->{tabs} }) {
        $self->make_current ($self->{tabs}[$idx]);
    }

    ();
}

sub move_tab {
  my ($self, $tab, $direction) = @_;

  if (@{ $self->{tabs} } > 1) {
    my $last = $#{$self->{tabs}};
    my $idx = 0;
    ++$idx while $self->{tabs}[$idx] != $tab;

    if ($idx == 0 && $direction == -1) {
      push @{$self->{tabs}}, shift @{$self->{tabs}};
      $idx = $last;
    } elsif ($idx == $last && $direction == 1) {
      unshift @{$self->{tabs}}, pop @{$self->{tabs}};
      $idx = 0;
    } else {
      ($self->{tabs}[$idx], $self->{tabs}[$idx + $direction]) =
        ($self->{tabs}[$idx + $direction], $self->{tabs}[$idx]);
      $idx += $direction;
    }
    $self->make_current ($self->{tabs}[$idx]);
  }

  ();
}

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

    if (!$self->{is_inputting_name}) {
        $self->{is_inputting_name} = 1;
        $tab->{old_name} = $tab->{name} ? $tab->{name} : "";
        $tab->{new_name} = "";
        $tab->{name} = "█";
        $self->update_autohide (1);
        $self->refresh;

        $tab->enable('key_press', sub {
            # rxvt-unicode-scroll-bug-fix.patch causes early key_press events to
            # be passed without $keysym or $octects arguments passed.  Work
            # around it by ignoring such invocations; we’ll be called again soon
            # with all those arguments.  The patch shouldn’t be used any more
            # anyway.
            if (@_ == 2) {
                    return 0;
            }

            my ($tab, $event, $keysym, $octets) = @_;

            if ($keysym == 0xff0d || $keysym == 0xff8d) { # enter
                $tab->{name} = $tab->{new_name};
                $self->{is_inputting_name} = 0;
                $tab->disable('key_press');
                $self->update_autohide (1);
            } elsif ($keysym == 0xff1b) { # escape
                $tab->{name} = $tab->{old_name};
                $self->{is_inputting_name} = 0;
                $self->update_autohide (1);
            } elsif ($keysym == 0xff08) { # backspace
                substr $tab->{new_name}, -1, 1;
                $tab->{name} = $tab->{new_name} . '█';
            } elsif ($octets !~ /[\x00-\x1f\x80-\xaf]/) {
                $tab->{new_name} .= $octets;
                $tab->{name} = $tab->{new_name} . '█';
            }
            $self->refresh;
            return 1;
        });
    }
}


sub tab_osc_seq_perl {
    my ($self, $tab, $osc) = @_;

    if ($osc =~ /^tabbedx;set_tab_name;(.*)$/) {
        if ($self->{is_inputting_name}) {
            $tab->{old_name} = $1;
        } else {
            $tab->{name} = $1;
        }
        $self->update_autohide (1);
        $self->refresh;
        1;
    }
}


package urxvt::ext::tabbedex::tab;

# helper extension implementing the subwindows of a tabbed terminal.
# simply proxies all interesting calls back to the tabbedex class.

{
   for my $hook ( qw(start destroy user_command property_notify
                     add_lines bell osc_seq_perl) ) {
      eval qq{
         sub on_$hook {
            my \$parent = \$_[0]{term}{parent}
               or return;
            \$parent->tab_$hook (\@_)
         }
      };
      die if $@;
   }
}

sub tab_name {
    my ($tab, $idx, $max_len) = @_;
    return substr($tab->{name} || ($idx + 1), -$max_len);
}