I just started learning, can someone please give me an answer?

Question

To implement folder traversal output, it is required to use red for folders and blue for files, and to have hierarchical indentation with four spaces,

function myscandir($dir){

//Judge whether the path is valid

//is_dir($dir) or die('Currently is not a directory');

echo $dir,'< /br>';

if (is_dir($dir)) {

# code...

echo ' '.' '.' ';

$files = scandir($dir);

foreach ($files as $file) {

## if($file ! =='.' && $file !== '..'){

echo ' '.' '.' ';

myscandir($file);

}

}

}

How to write this code?