/**
 * 在请求支付时，如果是文章，则仅显示余额支付
 */
add_filter('zibpay_payment_methods', 'force_balance_for_post_cashier', 10, 2);
function force_balance_for_post_cashier($methods, $pay_type) {
    $post_id = isset($_REQUEST['id']) ? (int) $_REQUEST['id'] : 0;
    
    if ($post_id) {
        $post_type = get_post_type($post_id);
        if ($post_type === 'post') {
            $payment_method_args = zibpay_get_payment_method_args();
            if (zibpay_is_allow_balance_pay($pay_type)) {
                return array('balance' => $payment_method_args['balance']);
            }
            return array();
        }
    }
    
    return $methods;
}