Choose role in register form (Woocommerce) - wordpress

Question

I'm building a site using Wordpress and WooCommerce. This site need to have 2 types of clients:
Normal customer (default customer of woocommerce)
B2B customer (this user have different prices and aditional products)
I need a checkbox to appear on the registration form.
When the user marks that checkbox, the b2b role would be assigned and additional fields would appear to complete the registration.
EDIT
I'm triying whit this code:
/*checkbox*/
add_action('woocommerce_after_checkout_billing_form', 'mostrar_campo_nif_profesionales');
function mostrar_campo_nif_profesionales( $checkout ) {
echo '<div id="mostrar_campo_nif_profesionales"><h3>'.__('¿Eres un profesional?').'</h3>';
woocommerce_form_field( 'check_profesional', array(
'type' => 'checkbox',
'class' => array('checkbox-profesionales form-row-wide'),
'label' => __('Profesional?'),
'required' => false,
), $checkout->get_value( 'profesional' ));
echo '</div>';
}
/*the field must appears when the checkbox are checked*/
if ("DON'T KNOW WHAT CONDITION MUST BE WRITE HERE") {
/*** Añadir campo personalizado a página de checkout ***/
add_action('woocommerce_after_checkout_billing_form', 'campo_nif_profesionales');
function campo_nif_profesionales( $checkout ) {
echo '<div id="campo_nif_profesionales"><h3>'.__('NIF/CIF').'</h3>';
woocommerce_form_field( 'NIF', array(
'type' => 'text',
'class' => array('my-field-class form-row-wide'),
'label' => __('NIF/CIF'),
'placeholder' => __('Introduzca su NIF/CIF'),
'required' => true,
), $checkout->get_value( 'NIF' ));
echo '</div>';
}
/*** Validación del campo personalizado ***/
add_action('woocommerce_checkout_process', 'campo_nif_profesionales_process');
function campo_nif_profesionales_process() {
global $woocommerce;
// Comprobar si el campo ha sido completado, en caso contrario agregar un error.
if (!$_POST['NIF'])
$woocommerce->add_error( __('Por favor introduce tu NIF o CIF.') );
}
/*** Incluir campo personalizado a formato de orden ***/
add_action('woocommerce_checkout_update_order_meta', 'campo_nif_profesionales_update_order_meta');
function campo_nif_profesionales_update_order_meta( $order_id ) {
if ($_POST['NIF']) update_post_meta( $order_id, 'NIF/CIF', esc_attr($_POST['NIF']));
}
/*** Incluir campo personalizado a correos electrónicos de órdenes ***/
add_filter('woocommerce_email_order_meta_keys', 'campo_nif_profesionales_order_meta_keys');
function campo_nif_profesionales_order_meta_keys( $keys ) {
$keys[] = 'NIF/CIF';
return $keys;
}
}
But now the problem is only show the text field when the users chek the checkbox

Answer 1

Part 1.
At the start there are two options,
Add fields you need at the Start of the page
Add fields that you need at the End of the Page.
This can be done by woocommerce_register_form_start hook or woocommerce_register_form.
Here , the only way I can think of is to by default include the fields for all but only reveal them by JS / JQ when used click on the check box.
This would fix the part of adding the fields.
Part 2.
Validation of the Submitted form
Use the Hook woocommerce_register_post and then get hold of the registration data that is sent back to the server. And Validate it from server side as well. Say if the box is checked and all the related fields have the necessary data as well and sanitize the fields as well.
Part 3.
Now add the additional Data as well as the additional role to the user.
Now use the user_register hook and get hold of the newly registered user's ID. And then add the new data in there.
A bit of caution is suggested, as this hook is fired on every user register so first add a validation to check that this user is a customer , and then check that this user is registered via the front end form, this is can normally be done by checking the $_POST variable.
Use the wp_update_user and add_role function to achieve this.
Sample Code for part 3
function add_user_additional_details_frontend_reg( $user_id )
{
$registered_user = get_user_by('ID',$user_id);
if($registered_user) {
$user_role = $registered_user->roles;
if((in_array('customer', (array) $user_role))){
/* The field below "front_end_cust_form" is just a hidden field I added to check and make sure that this is coming from the Front end Reg form where I added the additional fields */
if($_POST['front_end_cust_form'] == 'front_end_cust_form')
{
$first_name = $_POST['billing_first_name'];
$last_name = $_POST['billing_last_name'];
update_user_meta($user_id, 'billing_first_name', $first_name);
update_user_meta($user_id, 'billing_last_name', $last_name);
$update_data = array(
'ID' => $user_id,
'first_name' => $first_name,
'last_name' => $last_name
);
$user_id = wp_update_user($update_data);
$registered_user->add_role('custom_role');
}
}
}
}
add_action( 'user_register', 'add_user_additional_details_frontend_reg', 10, 1 );
Hope this helps.