use warnings;
use strict;
use Tk;
use Tk::Table;
use Data::Dumper;

my $buttonsPerRow = 5;
$buttonsPerRow -= 1; #button numbering starts from 0...
my $row = 0;
my $col = 0;
my $buttonNum = 0;
my @buttons;

my $mw = tkinit();
my $menuFrame = $mw->Frame()->pack(-expand=>1,-fill=>'both');
my $buttonFrame = $mw->Frame()->pack(-expand=>1,-fill=>'both');

my $table = $buttonFrame->Table(
		-columns => 5,
		-scrollbars => 'se',
		-fixedrows => 1,
	)->pack(-expand=>1,-fill=>'both');

my $addButton = $menuFrame->Button(
		-text			=> 'Add Button',
		-command 	=> sub{
			$buttons[$buttonNum] = $table->Button();
			$col>$buttonsPerRow?$row++:undef;
			$col>$buttonsPerRow?$col=1:$col++;
			print "Button $buttonNum->$row:$col\n";
			$buttons[$buttonNum]{'row'} = $row;
			$buttons[$buttonNum]{'col'} = $col;
			$table->put($row,$col,$buttons[$buttonNum]);
			configureButton($buttonNum);
			$buttonNum++;
		},
	)->pack(-side=>'top');


################################
#DragNDrop
my $isDragging = 0; #boolean - left mouse button pressed and dragging
my $selectedButton = 0;
$mw->bind('<Motion>', \&motion);
my %tableRows;
my %tableCols;

################################

$mw->MainLoop();

sub configureButton{
	#configure the new button
	my $btnNum = shift;
	$buttons[$btnNum]->bind('<Enter>', sub{
				$selectedButton = $btnNum;
			}
		);
	$buttons[$btnNum]->configure(
		-text => "Button $btnNum",
		-command => sub{
			print "Button $btnNum pressed\n";
		}
	);
	$buttons[$btnNum]->bind('<ButtonPress-1>', \&buttonPress);
	$buttons[$btnNum]->bind('<ButtonRelease-1>', \&buttonRelease);
}

sub motion {
	#what to do when the mouse is moving
	my($widget) = @_;
	my $e = $widget->XEvent;#get Tk Event
	if ($isDragging){
		findCell($e->X,$e->Y);	#get mouse cursor X/Y coorinates from event
	}
	return unless $isDragging;
}

sub buttonPress {
	#what to do when the left mouse button is pressed
	undef %tableRows; #undefine %tableRows hash in case row height has changed
	undef %tableCols; #undefine %tableCols hash in case column width has changed
	for(my $btnNum=0;$btnNum<@buttons;$btnNum++){ #recreate %tableRows and %tableCols - key=XY_coordinate val=row/col_number
		$tableRows{$buttons[$btnNum]->rooty} = $buttons[$btnNum]{'row'};
		$tableCols{$buttons[$btnNum]->rootx} = $buttons[$btnNum]{'col'};
	}
	$isDragging = 1;
	#Debugging... show root location of each row and column
	#foreach my $key (sort keys %tableRows){
	#	print "$key\n";
	#}
	#print "------\n";
	#foreach my $key (sort keys %tableCols){
	#	print "$key\n";
	#}
}

sub buttonRelease {
	#what to do when the left mouse button is released
	$isDragging = 0;
}

sub findCell{
	my $tmpX = shift;
	my $tmpY = shift;
	print "$tmpX:$tmpY\n";
	#determine which row and column the mouse cursor is currently hovering over
	# based on mouse X/Y coordinates.
}