In WooCommerce how can I make it so users can only buy 1 product per order and make it so on a specific product they can only buy it once per user?

Question

I'm building a ticketing website for events. I'm using WooCommerce and The Events Calendar plugin.

I've already made it so that users must be logged in to buy a ticket (product).

Then I found this code snippet that would limit it so that only 1 product can be purchased per order

add_filter( 'woocommerce_add_to_cart_validation', 'wc_limit_one_per_order', 10, 2 );
function wc_limit_one_per_order( $passed_validation, $product_id ) {
    if ( 31 !== $product_id ) {
        return $passed_validation;
    }

    if ( WC()->cart->get_cart_contents_count() >= 1 ) {
        wc_add_notice( __( 'This product cannot be purchased with other products. Please, empty your cart first and then add it again.', 'woocommerce' ), 'error' );
        return false;
    }

    return $passed_validation;
}

This would work, but in the first if statement you can see that the product ID has to be specified. I know I can also change this to an array like if ( ! in_array( $product_id, array( 31, 32, 33 ) ) ) { but the problem is that I would need to keep updating the IDs for every new event. Is there a way to do this so it applies to all products all the time? If not with code then maybe with settings or a plugin?

I also need to prevent customers (users) from returning to the site later and buying another ticket. So, I need to limit specific products so that only 1 of that SKU can be purchased per user account forever, meaning they can't just return to the site and start the buying process again. Is there a way to do this?

Many thanks in advance.

Answer 1

Is there a way to do this so it applies to all products all the time?

Sure. Just force the Cart to empty before adding a new item:

add_filter( 'woocommerce_add_to_cart_validation', 'bbloomer_only_one_in_cart', 9999, 2 );
   
function bbloomer_only_one_in_cart( $passed, $added_product_id ) {
   wc_empty_cart();
   return $passed;
}

Source and screenshot: https://www.businessbloomer.com/woocommerce-allow-1-product-cart/

I need to limit specific products so that only 1 of that SKU can be purchased per user account forever, meaning they can't just return to the site and start the buying process again

As @7uc1f3r said, please share the code you tried with and then we'll take a look