compare_directories.php

<?php
namespace Codeable;
function map_with_keys($cb,$a) {
	$na = [];
	foreach ($a as $k=>$v) {
		list($nk,$nv) = call_user_func_array($cb,[$k,$v]);
		$na[$nk] = $nv;
	}
	return $na;
}
function union_of_files($a,$b,$res=[]) {
	$cb = function ($k,$v) {
		$md5 = md5_file($v);
		return [$md5,$v];	
	};
	$files_only = function ($f) {
		if ( is_dir($f) || $f == '.' || $f == '..' ) {
			return false;
		}
		return true;
	};
	$dirs_only = function ($f) {
		if ( basename($f) == '.' || basename($f) == '..' ) {
			return false;
		}
		if ( ! is_dir($f) ) {
			return false;
		}
		return true;
	};
	$a_files = array_map(function ($p) use($a) { 
		return "$a/$p";}, scandir($a));
	$a_files_only = map_with_keys($cb,array_filter($a_files,$files_only));
	$b_files = array_map(function ($p) use($b) { 
		return "$b/$p";}, scandir($b));
	$b_files_only = map_with_keys($cb,array_filter($b_files,$files_only));
	foreach ( $b_files_only as $md5 => $path ) {
		if ( array_key_exists($md5,$a_files_only) ) {
			array_push($res,$path);	
		}
	}
	$a_dirs_only = array_filter(scandir($a),function ($p) use ($a,$dirs_only) {
		if ( $dirs_only("$a/$p") ) {
			return true;	
		}
		return false;
	});
	$b_dirs_only = array_filter(scandir($b),function ($p) use ($b,$dirs_only) {
		if ( $dirs_only("$b/$p") ) {
			return true;	
		}
		return false;
	});
	foreach ( $b_dirs_only as $path ) {
		if ( in_array($path,$a_dirs_only) ) {
			$res += union_of_files("$a/$path","$b/$path",$res);
		}
	}
	return $res;
}

/*
$woo = __DIR__ . "/../woocommerce/templates";
$theme = __DIR__ . "/../../themes/test/templates";
$files = union_of_files($woo,$theme);
print_r($files);
*/