#!/usr/bin/perl -w

use File::Find;

sub DirectorySize {
  my $dir = shift;
  my $sizeSum = 0;
  # Find all child files and directories and sum their sizes.
  find(sub {
      my @statData = stat;
      $sizeSum += $statData[12];
    }, $dir);
  return $sizeSum * 512;
}

sub HumanReadable {
  my $size = shift;
  for my $prefix (split //, " kMGTPEZ") {
    return sprintf("%.1f%s", $size, $prefix) if($size < 10);
    return sprintf("%.0f%s", $size, $prefix) if($size < 1000);
    $size /= 1024;
  }
  return sprintf("%.0fY", $size);
}

my $order = 1;

while (@ARGV) {
  my $arg = shift;
  $order *= -1 if ($arg =~ /^-r$/);
}

# Find all immediate children, except . and ..
my @children = grep { !/^\.{1,2}$/ } <* .*>;

# Count the sizes of the children.
my @childrenSizes = map { [ DirectorySize($_), $_ ] } @children;

# Sort by size.
@childrenSizes = sort { $order * ($a->[0] <=> $b->[0]) } @childrenSizes;

for my $childData (@childrenSizes) {
  printf("\e[1;31;43m*\e[0m %s\t%s\n", HumanReadable($childData->[0]), $childData->[1]);
}