process_directory_oop.php

<?php

function processDirectory($start = './', $format = 'array') {
	if (!empty($start)) {
		$start = rtrim($start, '/') . '/';
	}
	if (!empty($start) && !is_dir($start)) {
		return 'json' === $format ? 'false' : false;
	}

	$result = [];

	$flags = FilesystemIterator::KEY_AS_PATHNAME
		| FilesystemIterator::CURRENT_AS_FILEINFO
		| FilesystemIterator::SKIP_DOTS;

	$directory = new DirectoryIterator($start);
	foreach ($directory as $dir) {
		if ($dir->isDir() && !$dir->isDot()) {
			$files = $duplicates = $size = 0;
			$md5 = [];
			$iterator = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($dir->getPathname(), $flags));
			foreach ($iterator as $file) {
				$files++;
				$size += $file->getSize();
				$hash = md5_file($file->getPathname());
				if (empty($md5[$hash])) {
					$md5[$hash] = 1;
				} else {
					$duplicates++;
				}
			}
			$result[$dir->getFilename()] = [
				'total_size' => $size,
				'files' => $files,
				'duplicates' => $duplicates,
			];
		}
	}
	if (!empty($result)) {
		uasort($result, function ($a, $b) {
			if ($a['total_size'] > $b['total_size']) {
				return 1;
			}
			if ($a['total_size'] < $b['total_size']) {
				return -1;
			}
			return 0;
		});
	}

	return 'json' === $format ? json_encode($result) : $result;
}

if (!empty($argv[1])) {
	var_export(processDirectory($argv[1], !empty($argv[2]) ? $argv[2] : 'array'));
} else {
	var_export(processDirectory());
}