#!/usr/local/bin/perl -w
#

use strict;
use warnings;

use Tk;
my $mainWin = MainWindow->new();
$mainWin->resizable(0, 0);
$mainWin->title("Fit columns and rows");
my $rowsOrColumns = 1;
my $rowColText;
my $rowColFrame = $mainWin->Frame(
   -relief => "ridge",
   -borderwidth => 2)->pack(
      -side => "top",
      -fill => "y",
      -expand => 1);
$rowColFrame->Label(
   -textvariable => \$rowColText,
   -relief => 'flat',
   -borderwidth => 2,
   -padx=> 5,
   -pady => 5)->pack(
      -side => 'top');
my $chooseRowColFrame = $rowColFrame->Frame(
   -relief => "flat",
   -borderwidth => 2)->pack(
      -side => "top",
      -fill => "y",
      -expand => 1);
$chooseRowColFrame->Radiobutton(
   -text => "Rows",
   -width => 7,
   -value => 0,
   -variable => \$rowsOrColumns,
   -command => \&arrangeButtons)->pack(
      -side => "left",
      -padx => 5,
      -pady => 5);
$chooseRowColFrame->Radiobutton(
   -text => "Columns",
   -width => 7,
   -value => 1,
   -variable => \$rowsOrColumns,
   -command => \&arrangeButtons)->pack(
      -side => "left",
      -padx => 5,
      -pady => 5);
my $sortDirection = 0;
my $directionText;
my $directionFrame = $mainWin->Frame(
   -relief => "ridge",
   -borderwidth => 2)->pack(
      -side => "top",
      -fill => "y",
      -expand => 1);
$directionFrame->Label(
   -textvariable => \$directionText,
   -relief => 'flat',
   -borderwidth => 2,
   -padx=> 5,
   -pady => 5)->pack(
      -side => 'top');
my $chooseDirectionFrame = $directionFrame->Frame(
   -relief => "flat",
   -borderwidth => 2)->pack(
      -side => "top",
      -fill => "y",
      -expand => 1);
$chooseDirectionFrame->Radiobutton(
   -text => "Horizontal",
   -width => 10,
   -value => 0,
   -variable => \$sortDirection,
   -command => \&arrangeButtons)->pack(
      -side => "left",
      -padx => 5,
      -pady => 5);
$chooseDirectionFrame->Radiobutton(
   -text => "Vertical",
   -width => 10,
   -value => 1,
   -variable => \$sortDirection,
   -command => \&arrangeButtons)->pack(
      -side => "left",
      -padx => 5,
      -pady => 5);
my $numItems = 13;
my $itemsText;
my $itemCountFrame = $mainWin->Frame(
   -relief => "ridge",
   -borderwidth => 2)->pack(
      -side => "top",
      -fill => "y",
      -expand => 1);
$itemCountFrame->Label(
   -textvariable => \$itemsText,
   -relief => 'flat',
   -borderwidth => 2,
   -padx=> 5,
   -pady => 5)->pack(
      -side => 'top');
my $chooseItemsFrame = $itemCountFrame->Frame(
   -relief => "flat",
   -borderwidth => 2)->pack(
      -side => "top",
      -fill => "y",
      -expand => 1);
for (2 .. 27)
{
    $chooseItemsFrame->Radiobutton(
       -text => "$_",
       -value => $_,
       -variable => \$numItems,
       -width => 3,
       -command => \&arrangeButtons)->grid(
          -row => (($_ - 2) / 5),
          -column => (($_ - 2) % 5),
          -padx => 5,
          -pady => 5);
}
my $numRowsOrCols = 2;
my $rowColCountText;
my $rowColCountFrame = $mainWin->Frame(
   -relief => "ridge",
   -borderwidth => 2)->pack(
      -side => "top",
      -fill => "y",
      -expand => 1);
$rowColCountFrame->Label(
   -textvariable => \$rowColCountText,
   -relief => 'flat',
   -borderwidth => 2,
   -padx=> 5,
   -pady => 5)->pack(
      -side => 'top');
my $chooseColumnsFrame = $rowColCountFrame->Frame(
   -relief => "flat",
   -borderwidth => 2)->pack(
      -side => "top",
      -fill => "y",
      -expand => 1);
for (2 .. 7)
{
    $chooseColumnsFrame->Radiobutton(
       -text => "$_",
       -value => $_,
       -variable => \$numRowsOrCols,
       -command => \&arrangeButtons)->pack(
          -side => "left",
          -padx => 5,
          -pady => 5);
}
my $rhButtons = {};
my $buttonFrame = $mainWin->Frame(
   -relief => "ridge",
   -borderwidth => 2)->pack(
      -side => "top",
      -fill => "y",
      -expand => 1);
my $controlButtonFrame = $mainWin->Frame(
   -relief => "flat",
   -borderwidth => 2)->pack(
      -side => "top");
$controlButtonFrame->Button(
   -text => "Quit",
   -background => "SlateBlue3",
   -activebackground => "turquoise1",
   -foreground => "yellow1",
   -command => sub {exit;})->pack(
      -side => "right",
      -padx => 5,
      -pady => 5);
arrangeButtons();
MainLoop();

sub arrangeButtons
{
    foreach my $button (values %$rhButtons)
    {
        $button->destroy() if Exists($button);
    }
    setRowOrColumnText();
    setDirectionText();
    setItemsText();
    setRowColCountText();
    my $rlButtonOrder = $rowsOrColumns ?
       ($sortDirection ?
          fitToColsVSort($numItems, $numRowsOrCols) :
          fitToColsHSort($numItems, $numRowsOrCols)) :
       ($sortDirection ?
          fitToRowsVSort($numItems, $numRowsOrCols) :
          fitToRowsHSort($numItems, $numRowsOrCols));
    foreach my $buttonNo (1 .. $numItems)
    {
        my $buttonName = "Button_" . $buttonNo;
        $rhButtons->{$buttonName} = $buttonFrame->Button(
           -text => "Button $buttonNo",
           -width => 9)->grid(
              -row => $rlButtonOrder->[$buttonNo - 1]->[0],
              -column => $rlButtonOrder->[$buttonNo - 1]->[1],
              -padx => 5,
              -pady => 5);
    }
}

#   --------------
sub fitToColsVSort
#   --------------
{
    my($numItems, $numCols) = @_;
    my $rlOrder = [];
    my $leftOver = $numItems % $numCols;
    my $maxRowNo = $numItems / $numCols + ($leftOver ? 1 : 0);
    my $rowNo = 0;
    my $colNo = 0;
    for (1 .. $numItems)
    {
        push @$rlOrder, [$rowNo, $colNo];
        $rowNo ++;
        if($rowNo == $maxRowNo)
        {
           if($leftOver)
           {
               $leftOver --;
               $maxRowNo -- unless $leftOver;
           }
            $rowNo = 0;
            $colNo ++;
        }
    }
    return $rlOrder;
}

#   --------------
sub fitToColsHSort
#   --------------
{
    my($numItems, $numCols) = @_;
    my $rlOrder = [];
    foreach my $item (0 .. ($numItems - 1))
    {
        push @$rlOrder, [($item) / $numCols,
           ($item) % $numCols];
    }
    return $rlOrder;
}

#   --------------
sub fitToRowsVSort
#   --------------
{
    my($numItems, $numRows) = @_;
    my $rlOrder = [];
    foreach my $item (0 .. ($numItems - 1))
    {
        push @$rlOrder, [($item) % $numRows,
           ($item) / $numRows];
    }
    return $rlOrder;
}

#   --------------
sub fitToRowsHSort
#   --------------
{
    my($numItems, $numRows) = @_;
    my $rlOrder = [];
    my $leftOver = $numItems % $numRows;
    my $maxColNo = $numItems / $numRows + ($leftOver ? 1 : 0);
    my $rowNo = 0;
    my $colNo = 0;
    for (1 .. $numItems)
    {
        push @$rlOrder, [$rowNo, $colNo];
        $colNo ++;
        if($colNo == $maxColNo)
        {
           if($leftOver)
           {
               $leftOver --;
               $maxColNo -- unless $leftOver;
           }
            $colNo = 0;
            $rowNo ++;
        }
    }
    return $rlOrder;
}

#   ------------------
sub setRowOrColumnText
#   ------------------
{
    $rowColText = "By " . (qw(Rows Columns))[$rowsOrColumns] . " ...";
}

#   ----------------
sub setDirectionText
#   ----------------
{
    $directionText = "... sorting " .
       (qw(horizontally vertically))[$sortDirection] . " ...";
}

#   ------------
sub setItemsText
#   ------------
{
    $itemsText = "... fit $numItems items ...";
}

#   ------------------
sub setRowColCountText
#   ------------------
{
    $rowColCountText = "... to $numRowsOrCols " .
       (qw(rows columns))[$rowsOrColumns];
}