#!/usr/bin/perl

use strict;
use warnings;
use feature qw( state );
use Tk;

my ( @bHits, @rHits );
my ( @bList, @rList );
state $turn = 0;

my $mw = MainWindow->new( -title => 'Test Grid!' );
$mw->geometry( '1000x400+200+50' );
$mw->resizable( 0, 0 );
$mw->Label( -text       => 'Test Grid',
            -foreground => 'black',
          )->pack( -side   => 'top',
                   -expand => '0', );

my $mw_switch_b = $mw->Button(
            -text    => 'Switch',
            -command => sub { $turn ? disableBtns( \@bList, \@rList )
                                    : disableBtns( \@rList, \@bList ); }
                             )->pack;

my $mw_exit_b = $mw->Button( -text    => 'Exit',
                             -command => sub { exit }
                           )->pack;
my ( $blueFrame, $redFrame, $blHitFrame, $rdHitFrame );

$blueFrame = $mw->Frame;
$redFrame  = $mw->Frame;
### Blue Grid
for my $row ( 0 .. 9 ) {
    for my $col ( 0 .. 9 ) {;
        $blueFrame->Button( -text       => $col . $row,
                            -background => 'light blue',
                            -command    => [ \&showBtn ],
                          )->grid( -row => $row, -column => $col );
    }
}
### Red Grid
for my $row ( 0 .. 9 ) {
    for my $col ( 0 .. 9 ) {
        $redFrame->Button( -text       => $col . $row,
                           -background => 'indian red',
                           -command    => [ \&showBtn ],
                         )->grid( -row => $row, -column => $col );
    }
}

$blueFrame->pack( -side => 'left',  -padx => '10' );
$redFrame->pack( -side  => 'right', -padx => '10' );

@bList = $blueFrame->gridSlaves();
@rList = $redFrame->gridSlaves();

$blueFrame->repeat( 1000, \&update_button_colors);
$redFrame->repeat(  1000, \&update_button_colors);

MainLoop;

sub update_button_colors {
    foreach my $b ( @bList ) {
        $b->configure( -background => 'light blue' );
    }
    foreach my $r ( @rList ) {
        $r->configure( -background => 'indian red' );
    }
    return;
}
sub showBtn {
    ( $turn ) ? disableBtns( \@rList, \@bList )
              : disableBtns( \@bList, \@rList );
    return;
}
sub disableBtns {
    my @list = ( @_ ); # gridSlave references bList and rList
    for ( 0 .. 1 ) {
        foreach my $btn ( @{$list[$_]} ) {
            $_ ? $btn->configure( -state => 'disable' )
               : $btn->configure( -state => 'active' );
        }
    }
    $turn = !( $turn );
    return;
}