php - WooCommerce specific coupon discount based on product category

one text

Solution:

Since WooCommerce 3, there are many mistakes in your code… Also the $cart_item argument is included in the function, so you don't need to loop through cart items.

Also note that $coupon->is_type('percent') (coupon type) is not needed as you target a specific coupon in your code: $coupon->get_code() == 'newsite.

Try the following:

add_filter( 'woocommerce_coupon_get_discount_amount', 'alter_shop_coupon_data', 100, 5 );
function alter_shop_coupon_data( $discount, $discounting_amount, $cart_item, $single, $instance ){
    // Loop through applied WC_Coupon objects
    foreach ( WC()->cart->get_coupons() as $code => $coupon ) {
        if ( $coupon->is_type('percent') && $coupon->get_code() == 'newsite' ) {
            $discount = $cart_item['data']->get_price() * $cart_item['quantity'];
 
            if( has_term( 'cat1', 'product_cat', $cart_item['product_id'] ) ){
                $discount *= 0.2; // 20%
            }else{
                $discount *= 0.1; // 10%
            }
        }
    }
    return $discount;
}

Code goes in functions.php file of the active child theme (or active theme). It should better work.