php - Add or remove specific cart Item based on WooCommerce cart total

Question

I am trying to add a free product to the cart if the order total is above $199.99

I have achieved this and it is working. The issue is that I need to remove the product if the user then deletes an item from the cart and goes below $199.99 again (to prevent gaming the system).

What I have seems to be working. The problem is that it seems I need to click 2 links before the REMOVE FROM CART action seems to be working (or refresh the page).

What is causing this? Can the remove action be accomplished with AJAX by any chance?

// -------------------------------------------
// ADD PRODUCT IF ORDER MINIMUM ABOVE 200

/*
* Automatically adding the product to the cart when cart total amount reach to $199.99.
*/

function aapc_add_product_to_cart() {
    global $woocommerce;

    $cart_total = 199.99;   

    if ( $woocommerce->cart->total >= $cart_total ) {
        if ( is_user_logged_in() ) {
            $free_product_id = 339;  // Product Id of the free product which will get added to cart
            $found      = false;

            //check if product already in cart
            if ( sizeof( WC()->cart->get_cart() ) > 0 ) {
                foreach ( WC()->cart->get_cart() as $cart_item_key => $values ) {
                    $_product = $values['data'];
                    if ( $_product->get_id() == $free_product_id )
                        $found = true;                  
                }
                // if product not found, add it
                if ( ! $found )
                    WC()->cart->add_to_cart( $free_product_id );
            } else {
                // if no products in cart, add it
                WC()->cart->add_to_cart( $free_product_id );
            }        
        }
    }
    if ( $woocommerce->cart->total <= $cart_total && $found ) {
                WC()->cart->remove_cart_item( $free_product_id );
            }       
}

add_action( 'template_redirect', 'aapc_add_product_to_cart' );

add_action( 'template_redirect', 'remove_product_from_cart_programmatically' );

function remove_product_from_cart_programmatically() {
    if ( is_admin() ) return;
    $product_id = 339; // product id
    $cart_total = 199.99;
    $in_cart = false;
    foreach( WC()->cart->get_cart() as $cart_item_key => $cart_item ) {
        if ( $cart_item['product_id'] === $product_id ) {
            $in_cart = true;
            $key = $cart_item_key;
            break;
        }
    }
    if( WC()->cart->total < $cart_total ) {
        if ( $in_cart ) WC()->cart->remove_cart_item( $key );
    }
}

Answer 1

You should not use template_redirect hook to add or remove a free product based on a cart total threshold amount… Also your code is a bit outdated with some mistakes.

Instead use woocommerce_before_calculate_totals hook that is Ajax enabled, this way:

add_action( 'woocommerce_before_calculate_totals', 'add_or_remove_cart_items', 10, 1 );
function add_or_remove_cart_items( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    // ONLY for logged users (and avoiding the hook repetition) 
    if ( ! is_user_logged_in() && did_action( 'woocommerce_before_calculate_totals' ) >= 2 )
        return;

    $threshold_amount = 200; // The threshold amount for cart total
    $free_product_id  = 339; // ID of the free product
    $cart_items_total = 0; // Initializing

    // Loop through cart items
    foreach ( $cart->get_cart() as $cart_item_key => $cart_item ){
        // Check if the free product is in cart
        if ( $cart_item['data']->get_id() == $free_product_id ) {
            $free_item_key = $cart_item_key;
        }
        // Get cart subtotal incl. tax from items (with discounts if any)
        $cart_items_total += $cart_item['line_total'] + $cart_item['line_tax'];
    }

    // If Cart total is up to the defined amount and if the free products is not in cart, we add it.
    if ( $cart_items_total >= $threshold_amount && ! isset($free_item_key) ) {
        $cart->add_to_cart( $free_product_id );
    }
    // If cart total is below the defined amount and free product is in cart, we remove it.
    elseif ( $cart_items_total < $threshold_amount && isset($free_item_key) ) {
        $cart->remove_cart_item( $free_item_key );
    }
}

Code goes on functions.php file of your active child theme (or active theme). Tested and works.

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