WooCommerce Currency Switcher - Basic integration example

class Basic_CurrencySwitcher_Integration {
  /**
   * Basic integration with WooCommerce Currency Switcher, developed by Aelia
   * (http://aelia.co). This method can be used by any 3rd party plugin to
   * return prices converted to the active currency.
   *
   * Need a consultation? Find us on Codeable: https://aelia.co/hire_us
   *
   * @param double price The source price.
   * @param string to_currency The target currency. If empty, the active currency
   * will be taken.
   * @param string from_currency The source currency. If empty, WooCommerce base
   * currency will be taken.
   * @return double The price converted from source to destination currency.
   * @author Aelia <support@aelia.co>
   * @link https://aelia.co
   */
  protected function get_price_in_currency($price, $to_currency = null, $from_currency = null) {
    // If source currency is not specified, take the shop's base currency as a default
    if(empty($from_currency)) {
      $from_currency = get_option('woocommerce_currency');
    }
    // If target currency is not specified, take the active currency as a default.
    // The Currency Switcher sets this currency automatically, based on the context. Other
    // plugins can also override it, based on their own custom criteria, by implementing
    // a filter for the "woocommerce_currency" hook.
    //
    // For example, a subscription plugin may decide that the active currency is the one
    // taken from a previous subscription, because it's processing a renewal, and such
    // renewal should keep the original prices, in the original currency.
    if(empty($to_currency)) {
      $to_currency = get_woocommerce_currency();
    }

    // Call the currency conversion filter. Using a filter allows for loose coupling. If the
    // Aelia Currency Switcher is not installed, the filter call will return the original
    // amount, without any conversion being performed. Your plugin won't even need to know if
    // the multi-currency plugin is installed or active
    return apply_filters('wc_aelia_cs_convert', $price, $from_currency, $to_currency);
  }

    /**
     * Performs a simple test conversion.
     */
  public function test_conversion() {
    $price = 123;
    // Just call the get_price_in_currency() method, no further action required
    return $this->get_price_in_currency($price);
  }

    public function __construct() {
        add_filter('wc_aelia_currencyswitcher_product_convert_callback', array($this, 'wc_aelia_currencyswitcher_product_convert_callback'), 10, 2);
    }

    /**
     * Alter the callbacks used by the Currency Switcher, replacing the callback
     * for a "my_custom_product" type with a custon one.
     *
     * @param callable convert_callback The original callback.
     * @param WC_Product product The callback being converted.
     * @return callable The callback that will convert the product's prices.
     */
    public function wc_aelia_currencyswitcher_product_convert_callback($convert_callback, $product) {
        if($product->product_type === 'my_custom_product') {
            $convert_callback = array($this, 'convert_my_custom_product');
        }

        return $convert_callback;
    }

    /**
     * Converts the prices of a custom product to the specified currency.
     *
     * @param WC_Product product A variable product.
     * @param string currency A currency code.
     * @return WC_Product The product with converted prices.
     */
    public function convert_my_custom_product($product, $currency) {
        /* Here you can implement your custom logic to convert the prices.
         *  The two lines below are just an example. Here you can do anything you
         *  want with the product, to ensure that its prices are converted correctly.
         */
        $product->my_custom_price = $this->get_price_in_currency($product->my_custom_price);
        $product->my_other_custom_price = $this->get_price_in_currency($product->my_other_custom_price);

        return $product;
    }
}