#!/usr/bin/perl
use warnings;
use strict;

use Tk;
use Tk::Pane;
use Tk qw(:eventtypes);

my $mw = new MainWindow (-title=>" $0 MAIN");
my $phwin;
my $display_label;
my @to_show =('A'..'Z');

my $toggle_autoplay = 0;

my $fr0 = $mw->Frame()->pack();

$fr0->Button(  -text => "autoplay",
               -command =>  sub{$toggle_autoplay = 1; &autoplay},
               #[\&autoplay, Ev $toggle_autoplay?$toggle_autoplay=0:$toggle_autoplay=1],
      )->pack();
# ok same behaviour of ->update
#$mw->DoOneEvent(DONT_WAIT | ALL_EVENTS);#
# the above without bitmask run but not at the right interval
#also ok is:
$mw->update;
&secondary_win;
MainLoop;

################################################################################
sub autoplay {
       while($toggle_autoplay){

            $display_label->configure(-text=> shift @to_show);
            $phwin->update;
            #$phwin->DoOneEvent;
            sleep 1;
            #last if $phwin->waitVariable(\$toggle_autoplay);
       }
}
################################################################################
sub secondary_win {
    # window does not exists
    if (! Exists($phwin)) {
      $phwin = $mw->Toplevel();
      $phwin->title("SECONDARY");
      $phwin->bind('<KeyRelease-p>' => sub {
                                            print "BEFORE: bind-p = $toggle_autoplay\n";
                                            # THIS WORKS
                                            #if ($toggle_autoplay == 0){
                                            #   $toggle_autoplay = 1;
                                            #}
                                            #else{
                                            #    $toggle_autoplay = 0;
                                            #}
                                            # THE FOLLOWING DOES NOT WORKS! WHY?
                                            $toggle_autoplay == 0 ?
                                            $toggle_autoplay = 1  :
                                            $toggle_autoplay = 0  ;
                                            print "AFTER: bind-p = $toggle_autoplay\n";
      })
    }
    # window Exists
    else {
      $phwin->deiconify( ) if $phwin->state() eq 'iconic';
      $phwin->raise( ) if $phwin->state() eq 'withdrawn';
    }
    #my $scrolledframe = $phwin->Scrolled('Frame',-scrollbars => 'osoe')->pack();

    $display_label = $phwin->Label(-text=>'SECONDARY')->pack;
}