Change default currency on woocommerce depending on user country

functions.php

<?php
/**
* Change default WPML Woocommerce currency
* depending on user's country
* https://timersys.com/?p=21090&preview=true
*/
function geot_woo_default_currency( $currency ) {
  if( ! function_exists( 'geot_country_code' ) || isset( $_COOKIE['geot_currency'] ) )
    return $currency;
  
  $user_country = geot_country_code();
  switch( $user_country ) {
    case 'CH':
      $currency = 'CHF';
      break;
    case 'US':
      $currency = 'USD';
      break;
    default:
      $currency = 'EUR';
      break;
  }
  // save cookie to execute this only once
  setcookie( 'geot_currency', $currency, time() + (86400 * 30), "/");
  return $currency;

}
add_filter('wcml_client_currency','geot_woo_default_currency');