Convert all X/HTML files in a folder to valid X/HTML using libtidy via PHP

tidy-directory.php

<?php
	defined('TIDYDIR_EXTENSION') || define('TIDYDIR_EXTENSION', 'html');
	function tidyDir($directory) {
		$htmlFiles = glob($directory.DIRECTORY_SEPARATOR.'*.'.TIDYDIR_EXTENSION);
		$filenameRegEx = '#^(.+?)\.([^\.]+?)$#';
		$htmlTidy = new tidy();
		foreach ($htmlFiles as $entry) {
			if (preg_match($filenameRegEx, $entry, $matches)) {
				$filename = $matches[1];
				$extension = $matches[2];
				$htmlContents = file_get_contents($entry);
				$doctype = (preg_match('#\A\s*(\<[\s\S]+?\>)[\s\S]*#', $htmlContents, $matches))
							? $matches[1]."\n"
							: '';
				$htmlTidy->parseString($htmlContents);
				if (0 < $htmlTidy->getStatus()) {
					if ($htmlTidy->cleanRepair()) {
						$correctedHTML = $doctype.$htmlTidy->html()->value;
						echo 'saving ',$filename,'.',$extension,"\n";
						if (!file_put_contents($filename.'.'.$extension, $correctedHTML)) {
							echo 'failed saving ',$entry,"\n";
						}
					} else {
						echo 'FAILED TO CLEAN UP ',$entry,"\n";
						die;
					}
				} else {
					echo 'Goody, ',$entry,' is valid html ',"\n";
				}
			}
		}
		$d = dir($directory);
		while (false !== ($entry = $d->read())) {
			if (0 !== strpos($entry, '.') && is_dir($directory.DIRECTORY_SEPARATOR.$entry)) {
				echo 'calling tidyDir on ',$directory,DIRECTORY_SEPARATOR,$entry,"\n";
				tidyDir($directory.DIRECTORY_SEPARATOR.$entry);
			}
		}
	}
	tidyDir(__DIR__);