Discount based on cart items count and product cat

Question

I am trying to add a custom cart discount based on a minimal cart item count and categories.
I have take the code from this answer:
Cart discount based on cart item count and only for items that are not in sale

I have made some changes to it and this is my code:

add_action('woocommerce_cart_calculate_fees' , 'my_custom_discount', 10, 1);
function my_custom_discount( $cart_object ){

    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

        // Only when there is 4 or more items in cart
        if( $cart_object->get_cart_contents_count() >= 4):

        // Defining variables
            $categories = array('mycategory1','mycategory2');
            $has_category = false;

        // Iterating through each item in cart
        foreach( $cart_object->get_cart() as $cart_item ){
            // Getting an instance of the product object
            $_product = new WC_Product( $cart_item['product_id'] );

            // If a cart item has the category
            if(has_category($category, $_product)){
                $has_category = true;
                break;
            }
       }

       ## Discount calculation ##
       $discount = $cart_object->subtotal * -0.03;

       ## Applied discount (no products on sale) ##
       if($has_category )
           $cart_object->add_fee( '3% discount', $discount);

    endif;
}

I can’t make it work.

What I am doing wrong and How to make it work?

Thanks

Answer 1

As product categories are a custom taxonomy 'product_cat' you will need to use has_term() conditional function (instead of has_category()) this way:

add_action('woocommerce_cart_calculate_fees' , 'my_custom_discount', 10, 1);
function my_custom_discount( $cart_obj ){

    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    // Only when there is 4 or more items in cart
    if ( $cart_obj->get_cart_contents_count() > 3):

        // Set HERE your array of categories (slugs, IDs or names) <==  <==  <==  <==  <==
        $categories = array('mycategory1','mycategory2');

        // Initialising variable
        $has_category = false;


        // Iterating through each item in cart
        foreach( $cart_obj->get_cart() as $cart_item ){
            // The product ID
            $product_id = $cart_item['product_id'];

            // When a cart item is from one defined product categories we set $has_category to true.
            if ( has_term( $categories, 'product_cat', $product_id ) ) {
                $has_category = true;
                break;
            }
        }

        ## Discount calculation ##
        $discount = $cart_obj->subtotal * -0.03;

        ## Applied discount (for products (items) of defined product categories) ##
        if( $has_category )
            $cart_obj->add_fee( '3% discount', $discount);

    endif;
}

This code goes in function.php file of your active child theme (or theme) or also in any plugin file.

This code is tested and works for WooCommerce version 2.6+ and 3.0+