Code-Snippets-Functions/Execute a function on a child site/WooCommerce/auto-apply-coupons-based-on-cart-subtotal-thresholds,txt

add_action( 'woocommerce_before_calculate_totals' , 'discount_based_on_cart_items_subtotal' );
function discount_based_on_cart_items_subtotal( $cart ) { 
    if ( is_admin() && !defined('DOING_AJAX') )
        return;
    
    $subtotal = 0; // Initializing

    // Loop through cart items to get the subtotal excluding taxes
    foreach ( $cart->get_cart() as $item ) {
        $subtotal += $item['line_subtotal'];
    }
    
    if ( $subtotal >= 100 && $subtotal < 200 ) { 
        if ( ! $cart->has_discount('black10') ) {
            $cart->apply_coupon( 'black10' );
            $notice = __('10% OFF for '.wc_price(100).' or more - Discount Applied!');
        }
        if ( $cart->has_discount('black20') ) {
            $cart->remove_coupon( 'black20' );
        }
    } elseif ( $subtotal >= 200 ) {
        if ( ! $cart->has_discount('black20') ) {
            $cart->apply_coupon( 'black20' );
            $notice = __('20% OFF for '.wc_price(200).' or more - Discount Applied!');
        }
        if ( $cart->has_discount('black10') ) {
            $cart->remove_coupon( 'black10' );
        }
    }
    
    if ( isset($notice) ) {
        wc_clear_notices();
        wc_add_notice( $notice, 'notice' );
    }
}