For completeness, and for a bit of content on the typically lower volume Sunday...

Set the time, called only once, upon initial loading of the webapp:

$api->set_light_times;
[download]

Sets the light timers... once on initialization of the app as a whole, and then again every time the light-off is triggered:

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

    my $on_at = $self->_config_light('on_at');

    my $time = time;
    $time += 60 until localtime($time) =~ /$on_at:/;

    my $hrs = $self->_config_light('on_hours');

    my $on_time = $time;
    my $off_time = $on_time + $hrs * 3600;

    my $now = time;

    # check if the until() loop set things beyond today's
    # on period

    if ($now > ($on_time - 86400) && $now < ($off_time - 86400)){
        $on_time -= 24 * 3600;
        $off_time -= 24 * 3600;
    }

    $self->db()->update(
        'light', 'value', $on_time, 'id', 'on_time'
    );
    $self->db()->update(
        'light', 'value', $off_time, 'id', 'off_time'
    );

}
[download]

...and the action logic itself:

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

    my $log = $log->child('action_light');

    my $on_hours = $self->_config_light('on_hours');
    my $aux      = $self->_config_control('light_aux');
    my $pin      = $self->aux_pin($aux);
    my $on_time  = $self->_config_light('on_time');
    my $off_time = $self->_config_light('off_time');

    my $now = time;

    if (($on_hours == 24) || ($now > $on_time && $now < $off_time)){
        if (! $self->aux_state($aux)){
            $self->aux_state($aux, ON);
            pin_mode($pin, OUTPUT);
            write_pin($pin, HIGH);
        }
    }
    elsif ($self->aux_state($aux)){
        $self->aux_state($aux, OFF);
        pin_mode($pin, OUTPUT);
        write_pin($pin, LOW);
        $self->set_light_times;
    }
}
[download]