add_action( 'woocommerce_cart_calculate_fees', 'custom_auction_charge' );	

function custom_auction_charge( $cart_object ) {

    $spfee = 0.00; // initialize special fee, absolute amount
    $spfeeperprod = 0.20; //special fee per product, percentage

    foreach ( $cart_object->cart_contents as $key => $value ) {

        $proid = $value['product_id']; //get the product id from cart
        $quantiy = $value['quantity']; //get quantity from cart
        $product = wc_get_product( $proid  ); //

        if('auction' == $product->get_type()) :

        	if ($product->get_auction_closed() == 2){
            		$itmprice = $value['data']->get_auction_current_bid(); //get product price	
            		$spfee = $spfee + $itmprice * $quantiy * $spfeeperprod;
            }		
       	endif;  

	}
    if($spfee > 0 ) {
    	WC()->cart->add_fee( 'Buyers Premium', $spfee, true, 'standard' );
    }
}


add_filter( 'wsa_stripe_automatic_charge_order', 'auctions_for_woocommerce_stripe_automatic_charge_addfee', 10, 2 );
function auctions_for_woocommerce_stripe_automatic_charge_addfee( $order, $auctions_id ) {

    $fee_per_auction    = 0.20; //special fee per product, percentage
    $spfee              = $spfee = 0.00; // initialize special fee, absolute amount
    
    $product         = wc_get_product( $auctions_id );
    $item_price      = $product->get_auction_current_bid();
    $global_fee      = $spfee + $item_price * $fee_per_auction;
    $item_fee        = new WC_Order_Item_Fee();

    $item_fee->set_name( 'BPA' );
    $item_fee->set_amount( $global_fee );
    $item_fee->set_total( $global_fee );
    $order->add_item( $item_fee );
    $note = sprintf( 
                __( 'WSA Stripe Auto Charge Log: This order includes a %s Buyers Premium fee.', 'woocommerce' ), 
                $global_fee 
            );

    $order->add_order_note( $note, true ); // true if you want the customer to see order note about fees

    return $order;
}