Coding help to implement Ubercart Marketplace to achieve per user per node access

This is what I'm trying to achieve -

UC marketplace to have sellers create and sell video nodes. I'm not able to figure out how to make this work, basically achieve per user per node access.

A user will see a teaser of the node with add to cart button and after the purchase they can see the full video node and it gets listed under their account.

I have tried to create a custom module with ACL and Ubercart, but its not working. After a purchase the code gives the buyer access to all the video nodes rather than a particular purchased node.

if ($order->order_status == 'completed' || $arg2 == 'completed') {
foreach ($order->products as $product) {
$node = node_load(array('nid' => $product->nid));
if ($node->type == variable_get('custom_node_type', DEFAULT_CUSTOM_NODE_TYPE)) {
$acl_id = _get_content_access_acl_id($node);
acl_add_user($acl_id, $order->uid);
}

And, then it tries to compare and provide view access as:

$users = acl_get_uids(_get_content_access_acl_id($node));
if ($users && in_array($user->uid, $users)) {
_remove_node_purchase_details($node);
}

Looking for a programmer who can either correct this code or create a new code to achieve this.