WooCommerce introduced a function which makes things much more elegant and simple, and gets rid of global $woocommerce and $aUrl when getting page URLs.
How to get WooCommerce page URLs in WooCommerce 3.x
WooCommerce introduced a function which makes things much more elegant and simple, and gets rid of global $woocommerce and $aUrl when getting page URLs.
The built-in function woocommerce_customer_bought_product can be used to check if a user has bought an item.