Add a downloadable product to a user's account when a WooCommerce Subscription is created

info.txt

Let's say you run a WooCommerce subscription website, and you'd like to automatically add
a downloadable product to a subscriber's account when they activate their subscription. 
Here's one way to do it:

woocom_sub.php

// Free downloadable product with a new subscription

add_action('activated_subscription', 'djr_subscription_activated');
function djr_subscription_activated( $userID ) {
  //Change your product ID below
  djr_create_order( $userID, 19700 );
}

function djr_create_order( $userID, $productID ) {
    $user = get_userdata( $userID );
    $args = array(
        'customer_id' => $userID,
        'customer_note' => 'Free item added via subscription'
    );
    $create_order = wc_create_order($args);

    $pf = new WC_Product_Factory();  
    $product = $pf->get_product($productID);
    $create_order->add_product($product);
    if( $product->is_downloadable() ) {
        $download_files = $product->get_files();
        foreach ( $download_files as $download_id => $file ) {
            wc_downloadable_file_permission( $download_id, $product->id, $create_order );
        }
    }
    $create_order->update_status('completed');
}