class WC_mypayment extends WC_Payment_Gateway{
            public function __construct(){

                $this->id = 'mypayment';
                $this->method_title = __('Pago mediante TPV','woocommerce');
                $this->method_description = __('Establecer los metodos de pago mediante TPV','woocommerce');

                // Carga de form
                $this->setup_form();
                $this->init_settings(); // function de woocommerce

                // Get options
                $this->title = $this->get_option('titulo');
                $this->description = $this->get_option('descripcion');
                $this->nombre_comercio = $this->get_option('nombre_comercio');

                //Add actions para woocommerce
                add_action( 'woocommerce_receipt_mypayment', array( $this, 'receipt_page' ) );
                add_action( 'woocommerce_update_options_payment_gateways_' . $this->id, array( $this, 'process_admin_options' ) );
            }
public function setup_form(){
                global $woocommerce;
// aqui establezco los parametros necesarios para configuracion, en la parte admin no tengo problema

}
function receipt_page($order){
    echo "<p>".__("Gracias, nuestro metodo",'mypayment')."</p>";
}

} // end class
function add_mypayment_gateway($methods){
            $methods[]="WC_mypayment";return $methods;
        }
        add_filter('woocommerce_payment_gateways','add_mypayment_gateway');