Add both folders and files into zip (PHP) - php

Question

I am looking to add both folders and files from a matching array to a zip file. Below is my code:
function listdir($start_dir='./assets') {
//Array that will contain the director
$files = array();
if (is_dir($start_dir)) {
$fh = opendir($start_dir);
while (($file = readdir($fh)) !== false) {
// Loop through the files, skipping '.' and '..', and recursing if necessary
if (strcmp($file, '.')==0 || strcmp($file, '..')==0) continue;
$filepath = $start_dir . '/' . $file;
if ( is_dir($filepath) )
$files = array_merge($files, listdir($filepath));
//else
array_push($files, $filepath);
}
closedir($fh);
} else {
// false if the function was called with an invalid non-directory argument
$files = false;
}
return $files;
}
//Array of all files
$allFiles = listdir('./assets');
print_r($allFiles);
//Gets all values with name "asset"
$name = $_POST['asset'];
//If there are items in the array, zip them together
if($name!=0){
//Compares $_POST array with array of all files in directory
$result = array_intersect($allFiles, $name);
function zipFilesAndDownload($result){
$zip = new ZipArchive();
//create the file and throw the error if unsuccessful
if ($zip->open('SelectedAssets.zip', ZIPARCHIVE::CREATE )!==TRUE) {
exit("cannot open SelectedAssets.zip\n");
}
//add each files of $file_name array to archive
foreach($result as $allFiles) {
$zip->addFile($allFiles);
}
$zip->close();
$zipped_size = filesize('SelectedAssets.zip');
header("Content-Description: File Transfer");
header("Content-type: application/zip");
header("Content-Type: application/force-download");// some browsers need this
header("Content-Disposition: attachment; filename=SelectedAssets.zip");
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header("Content-Length:". " $zipped_size");
ob_clean();
flush();
readfile("SelectedAssets.zip");
unlink("SelectedAssets.zip"); // Now delete the temp file (some servers need this option)
exit;
}
if(isset($_POST['submit'])) {
//$file_names=$_POST['assets'];// Always sanitize your submitted data!!!!!!
//$file_names = filter_var_array($_POST['assets']);//works but it's the wrong method
$filter = filter_input_array(INPUT_POST, FILTER_SANITIZE_SPECIAL_CHARS) ;
$file_names = $filter['assets'] ;
//Archive name
$archive_file_name='DEMO-archive.zip';
//Download Files path
$file_path= getcwd(). './';
//call the function
zipFilesAndDownload($result);
} else {
print 'Something went wrong.';
exit;
}
} //Otherwise, don't.
else {
print_r("Please select a file.");
}
The code above searches through a directory and reads all the folders and files. Then using array_intersect I matched files that were put into an empty array by the user to all the files in the previously searched directory. I then zip the files that match and download.
My question is, how can I have a folder be added to this zip as well? As of now, this only adds files and folders are assumed as empty.