Remove conditionally Woocommerce cart items based on a specific product - php

Question

A specific WooCommerce product can only be by itself in the cart.
So how do I clear the cart while adding this specific product to the cart? and how can I remove this specific product from the cart when adding any other product?
I've figured out how to empty the cart when adding a specific product but I don't know how to remove this specific product from the cart when adding any other product.

Answer 1

The following will remove conditionally cart items based on a specific product:
When the specific product is added to cart, all other items are removed.
When any other product is added to cart, it removes the specific product (if it's in cart)
Here is the code:
// Remove conditionally cart items based on a specific product (item)
add_action( 'woocommerce_before_calculate_totals', 'remove_cart_items_conditionally', 10, 1 );
function remove_cart_items_conditionally( $cart ) {
// HERE define your specific product ID
$specific_product_id = 37;
if ( is_admin() && ! defined( 'DOING_AJAX' ) )
return;
$cart_items = $cart->get_cart(); // Cart items array
$items_count = count($cart_items); // Different cart items count
// Continue if cart has at least 2 different cart items
if ( $items_count < 2 )
return;
$last_item = end($cart_items); // Last cart item data array
$is_last_item = false; // Initializing
// Check if the specific product is the last added item
if ( in_array($specific_product_id, array( $last_item['product_id'], $last_item['variation_id'] ) ) ) {
$is_last_item = true;
}
// Loop through cart items
foreach ( $cart_items as $cart_item_key => $cart_item ) {
// Remove all others cart items when specific product ID is the last added to cart
if ( ! in_array($specific_product_id, array( $cart_item['product_id'], $cart_item['variation_id'] ) ) && $is_last_item ) {
$cart->remove_cart_item( $cart_item_key );
}
// Remove the specific item when its is not the last added to cart
elseif ( in_array($specific_product_id, array( $cart_item['product_id'], $cart_item['variation_id'] ) ) && ! $is_last_item ) {
$cart->remove_cart_item( $cart_item_key );
}
}
}
Code goes on function.php file of your active child theme (or active theme). Tested and works.

Answer 2

The above works perfectly! You can also add a notice to the cart once items have been removed to help with the user experience. Add this to the // Loop through cart items section in the first if statement:
wc_add_notice( __( 'Product XYZ has been removed from your cart because...', 'theme_domain' ), 'notice' );