Adding vendor signup option in checkout page (Dokan multivendor, WooCommerce)

gistfile1.txt

/*
* Adding vendor signup option in checkout page (Dokan multivendor, WooCommerce). 
* In checkout page, we are providing custom fields, so if a customer interested to become a vendor, they must fill out his
* store name and store url. 
*
* These 2 fields will be saved into User's database and integrated to Dokan framework.
*/


add_action('woocommerce_after_checkout_billing_form', 'fluf_vendor_registration_checkout');
function fluf_vendor_registration_checkout($checkout) {

    woocommerce_form_field('custom_field_name_one', array(
      'type' => 'checkbox',
      'class' => array(
        'vendor-choice-checkout form-row-wide'
      ) ,
      'label' => __('I\'d like to sell clothes free of charge') ,
    ),

    $checkout->get_value('custom_field_name_one'));

    echo '<div class="store-fields">';
        woocommerce_form_field('store_name', array(
          'type' => 'text',
          'required'	=> true,
          'class' => array(
            'store-name-checkout form-row-wide'
          ) ,
          'label' => __('Store Name') ,
        ),

        $checkout->get_value('store_name'));

        woocommerce_form_field('seller_url', array(
          'type' => 'text',
          'required'	=> true,
          'class' => array(
            'store-url-checkout form-row-wide'
          ) ,
          'label' => __('Store URL') ,
        ),

        $checkout->get_value('seller_url'));

    echo '</div>';
}



add_action( 'woocommerce_checkout_process', 'fluf_validate_new_checkout_field' );
function fluf_validate_new_checkout_field() {
   if ( ! $_POST['store_name'] ) {
      wc_add_notice( 'Please enter your Store Name', 'error' );
   }
   if ( ! $_POST['seller_url'] ) {
      wc_add_notice( 'Please enter your Store URL', 'error' );
   }
}


add_action( 'woocommerce_checkout_update_order_meta', 'fluf_save_new_checkout_field' );
function fluf_save_new_checkout_field( $order_id ) {
    if ( $_POST['store_name'] ) update_post_meta( $order_id, '_store_name', esc_attr( $_POST['store_name'] ) );
    if ( $_POST['seller_url'] ) update_post_meta( $order_id, '_seller_url', esc_attr( $_POST['seller_url'] ) );
}


add_action( 'woocommerce_thankyou', 'fluf_change_role_on_purchase' );
function fluf_change_role_on_purchase( $order_id ) {

// get order object and items
	$order = wc_get_order( $order_id );
	$items = $order->get_items();


  $order_id = $order->get_id();
  if ( get_post_meta( $order_id, '_seller_url', true ) ) echo '<p><strong>seller url:</strong> ' . get_post_meta( $order_id, '_seller_url', true ) . '</p>';

  if ( get_post_meta( $order_id, '_store_name', true ) ) echo '<p><strong>store name:</strong> ' . get_post_meta( $order_id, '_store_name', true ) . '</p>';


  $seller_url = get_post_meta( $order_id, '_seller_url', true );
  $store_name = get_post_meta( $order_id, '_store_name', true );


  $data = array();
  if( isset( $seller_url ) ) {

  foreach ( $items as $item ) {
    $product_id = $item->get_product_id();

    if( $product_id == $item['product_id'] && $order->user_id ) {

      $user = new WP_User( $order->user_id );

			// Remove old role
      //$user->remove_role( 'customer' );

        $data['shopurl'] = $seller_url;
        $data['shopname'] = $store_name;
        // Add new role
        $user->add_role( 'seller' );
        dokan_user_update_to_seller($user, $data);

      }
		}
	}

}