move data from filesystem to database - php

Question

I need to move data from filesystem to database
main folder is home with files and subfolders on various levels
my idea is to loop trough all folders using DirectoryIterator - and get filename and content of each file inside the current folder
this code shows Fatal error:
Uncaught UnexpectedValueException: DirectoryIterator... on line 53
I think the problem is actually with line 72 but all my attempts are unsuccessful
Please help
function go($path){
global $db;
$it = new DirectoryIterator($path); // line 53
foreach ($it as $a){
if ($a->isDot()){continue;}
if($a->isDir()){
$fopath = $it->getPathname();
$foname = $a->getFilename();
$foid = uniqid();
$sq = "insert into nts (id, what, title) values (:aid, :awhat, :atitle)";
$st = $db->prepare($sq);
$st->execute([":aid" => $foid, ":awhat" => 'fo', ":atitle" => $foname]);
$arr = array_filter(glob($fopath . "/*"), 'is_file');
foreach($arr as $el){
$fiid = uniqid();
$finame = basename($el, '.txt');
$story = file_get_contents($el);
$sq = "insert into nts (id, what, par, title, story) values (:aid, :awhat, :apar, :atitle, :astory)";
$st = $db->prepare($sq);
$st->execute([":aid" => $fiid, ":awhat" => 'fi', ":apar" => $foid, ":atitle" => $finame, ":astory" => $story]);
}
go("{$path}{$a->getPathname()}/"); // line 72
}
}
}}
}
go("home/");