#! perl -w
# Author:   Bert Muennich
# Website:  http://www.github.com/muennich/urxvt-perls
# License:  GPLv2

# Use keyboard shortcuts to select and copy text.

# Usage: put the following lines in your .Xdefaults:
#   URxvt.perl-ext-common: ...,keyboard-select
#   URxvt.keysym.M-Escape: perl:keyboard-select:activate

# Use Meta-Escape to activate selection mode, then use the following keys:
#   h/j/k/l:    move cursor left/down/up/right (also with arrow keys)
#   g/G/0/^/$:  vi-like cursor movement keys
#   H/M/L:      move cursor to first/center/last line of visible area
#   Ctrl-f/b:   move cursor one screen down/up
#   Ctrl-d/u:   move cursor half a screen down/up
#   v/V/Ctrl-v: toggle normal/linewise/blockwise selection
#   y,Return:   copy selected text to primary buffer and quit selection mode
#   Escape:     cancel whole keyboard selection mode


use strict;

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

	if ($cmd eq 'keyboard-select:activate') {
		if (not $self->{active}) {
			activate($self);
		}
	}

	()
}


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

	if ($keysym == 0xff1b) {
		# escape
		deactivate($self);
	} elsif ($char eq 'y' || $keysym == 0xff0d) {
		if ($self->{select}) {
			my ($br, $bc, $er, $ec) = calc_span($self);
			$self->selection_beg($br, $bc);
			$self->selection_end($er, $ec);
			$self->selection_make($event->{time}, $self->{select} eq 'b');
			deactivate($self);
		}
	} elsif ($char eq 'V') {
		toggle_select($self, 'l');
	} elsif ($char eq 'v') {
		if ($event->{state} & urxvt::ControlMask) {
			toggle_select($self, 'b');
		} else {
			toggle_select($self, 'n');
		}
	} elsif ($char eq 'k' || $keysym == 0xff52) {
		move_cursor($self, 'k');
	} elsif ($char eq 'j' || $keysym == 0xff54) {
		move_cursor($self, 'j');
	} elsif ($char eq 'h' || $keysym == 0xff51) {
		move_cursor($self, 'h');
	} elsif ($char eq 'l' || $keysym == 0xff53) {
		move_cursor($self, 'l');
	} elsif ('fbdu' =~ m/\Q$char\E/ && $event->{state} & urxvt::ControlMask) {
		move_cursor($self, $char);
	} elsif ('gG0^$HML' =~ m/\Q$char\E/) {
		move_cursor($self, $char);
	}

	return 1;
}


sub tt_write {
	return 1;
}


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

	if ($self->{select}) {
		my ($br, $bc, $er, $ec) = calc_span($self);

		if ($self->{select} eq 'b') {
			$self->scr_xor_rect($br, $bc, $er, $ec, urxvt::RS_RVid);
		} else {
			$self->scr_xor_span($br, $bc, $er, $ec, urxvt::RS_RVid);
		}

		if ($self->{select} ne 'l') {
			# make the cursor visible again
			$self->scr_xor_span($self->{cr}, $self->{cc},
					$self->{cr}, $self->{cc} + 1, urxvt::RS_RVid);
		}
	}

	()
}


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

	if ($self->{active}) {
		if ($key eq 'k' && $self->{cr} > $self->top_row) {
			--$self->{cr};
		} elsif ($key eq 'j' && $self->{cr} < $self->nrow - 1) {
			++$self->{cr};
		} elsif ($key eq 'h' && $self->{cc} > 0) {
			--$self->{cc};
		} elsif ($key eq 'l' && $self->{cc} < $self->ncol - 1) {
			++$self->{cc};
		} elsif ($key eq 'f' || $key eq 'd') {
			$self->{cr} += $key eq 'd' ? ($self->nrow - 1) / 2 : $self->nrow - 1;
			$self->{cr} = $self->nrow - 1 if $self->{cr} > $self->nrow;
		} elsif ($key eq 'b' || $key eq 'u') {
			$self->{cr} -= $key eq 'u' ? ($self->nrow - 1) / 2 : $self->nrow - 1;
			$self->{cr} = $self->top_row if $self->{cr} < $self->top_row;
		} elsif ($key eq 'g') {
			($self->{cr}, $self->{cc}) = ($self->top_row, 0);
		} elsif ($key eq 'G') {
			($self->{cr}, $self->{cc}) = ($self->nrow - 1, 0);
		} elsif ($key eq '0') {
			$self->{cc} = 0;
		} elsif ($key eq '^') {
			my $ltxt = $self->special_decode($self->line($self->{cr})->t);
			while ($ltxt =~ s/^( *)\t/$1 . " " x (8 - length($1) % 8)/e) {}
			$self->{cc} = $ltxt =~ m/^ +/ ? $+[0] : 0;
		} elsif ($key eq '$') {
			my $ltxt = $self->line($self->{cr})->t;
			$self->{cc} = ($ltxt =~ m/$/ ? $-[0] : $self->ncol) - 1;
		} elsif ($key eq 'H') {
			$self->{cr} = $self->view_start();
		} elsif ($key eq 'M') {
			$self->{cr} = $self->view_start() + $self->nrow / 2;
		} elsif ($key eq 'L') {
			$self->{cr} = $self->view_start() + $self->nrow - 1;
		}

		$self->screen_cur($self->{cr}, $self->{cc});

		# scroll the current cursor position into visible area
		if ($self->{cr} < $self->view_start()) {
			$self->view_start($self->{cr});
		} elsif ($self->{cr} >= $self->view_start() + $self->nrow) {
			$self->view_start($self->{cr} - $self->nrow + 1);
		}

		$self->want_refresh();
	}
	
	()
}


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

	$self->{active} = 1;
	$self->{select} = "";

	($self->{cr}, $self->{cc}) = $self->screen_cur();
	$self->{oldcr} = $self->{cr};
	$self->{oldcc} = $self->{cc};

	$self->selection_beg(1, 0);
	$self->selection_end(1, 0);

	$self->{view_start} = $self->view_start();
	$self->{pty_ev_events} = $self->pty_ev_events(urxvt::EV_NONE);

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

	()
}


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

	$self->screen_cur($self->{oldcr}, $self->{oldcc});

	$self->selection_beg(1, 0);
	$self->selection_end(1, 0);

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

	$self->want_refresh();

	$self->{active} = 0;

	()
}


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

	if ($self->{active}) {
		if ($self->{select} eq $mode) {
			$self->{select} = '';
		} else {
			if (not $self->{select}) {
				$self->{ar} = $self->{cr};
				$self->{ac} = $self->{cc};
			}
			$self->{select} = $mode;
		}

		$self->want_refresh();
	}

	()
}


sub calc_span {
	my ($self) = @_;
	my ($br, $bc, $er, $ec);
	
	if ($self->{cr} < $self->{ar}) {
		$br = $self->{cr};
		$bc = $self->{cc};
		$er = $self->{ar};
		$ec = $self->{ac};
	} elsif ($self->{cr} > $self->{ar}) {
		$br = $self->{ar};
		$bc = $self->{ac};
		$er = $self->{cr};
		$ec = $self->{cc};
	} else {
		$br = $self->{cr};
		$bc = $self->{cc} < $self->{ac} ? $self->{cc} : $self->{ac};
		$er = $self->{cr};
		$ec = $self->{cc} > $self->{ac} ? $self->{cc} : $self->{ac};
	}

	if ($self->{select} eq 'l') {
		$bc = 0;
		$ec = $self->ncol;
	} else {
		if ($self->{select} eq 'b') {
			($br, $er) = ($er, $br) if $br > $er;
			($bc, $ec) = ($ec, $bc) if $bc > $ec;
		}
		++$ec;
	}

	return ($br, $bc, $er, $ec);
}