WooCommerce：購買力平價（PPP）折扣

/**
 * @snippet       Get Billing Country @ WooCommerce Checkout
 * @how-to        Get CustomizeWoo.com FREE
 * @author        Rodolfo Melogli
 * @compatible    WooCommerce 6
 * @donate $9     https://businessbloomer.com/bloomer-armada/
 */

add_action( 'woocommerce_checkout_update_order_review', 'bbloomer_ppp' );

function bbloomer_ppp( $post_data ) {
   parse_str( $post_data, $output );
   if ( $output['billing_country'] ) {
      $country_code_2 = $output['billing_country'];
      // THEN, DO SOMETHING WITH COUNTRY CODE
   }
}

/**
 * @snippet       Get Currency, Ex Rate & PPP By Billing Country
 * @how-to        Get CustomizeWoo.com FREE
 * @author        Rodolfo Melogli
 * @compatible    WooCommerce 6
 * @donate $9     https://businessbloomer.com/bloomer-armada/
 */

// GET CURRENCY CODE
$locale_info = include WC()->plugin_path() . '/i18n/locale-info.php';	
$currency = $locale_info[$output['billing_country']]['currency_code'];

// GET EXCHANGE RATE
$req_url = 'https://api.exchangerate.host/latest/?base=USD&symbols=' . $currency;
$response_json = file_get_contents( $req_url );
$response = json_decode( $response_json );
if ( $response->success === true ) {
	$exchange_rate = $response->rates->{$currency};
}

// GET COUNTRY PPP VALUE (AVERAGE FOR PREVIOUS 5 YEARS)
$ppp_url = 'https://api.worldbank.org/v2/country/' . $country_code_3 . '/indicator/PA.NUS.PRVT.PP?date=' . date( "Y", strtotime( "-5 years" ) ) . ':' . date( "Y", strtotime( "-1 year" ) ) . '&format=json';
$ppp = json_decode( file_get_contents( $ppp_url ), true );
$values = array();
foreach ( $ppp[1] as $key => $val ) {
	if ( $val['date'] && $val['value'] ) {
		$values[$val['date']] = (float) $val['value'];
	}
}
$avg_ppp = array_sum( $values ) / count( $values );

/**
 * @snippet       Show Notice @ WooCommerce Checkout
 * @how-to        Get CustomizeWoo.com FREE
 * @author        Rodolfo Melogli
 * @compatible    WooCommerce 6
 * @donate $9     https://businessbloomer.com/bloomer-armada/
 */

$message = 'Your country is eligible for a ' . $discount . '% discount on courses! Read more about Purchasing Power Parity <a href="/woocommerce-purchasing-power-parity-discounts" target="_blank">here</a>. <a href="' . esc_url( add_query_arg( 'ppp', $discount, wc_get_checkout_url() ) ) . '" class="button wc-forward">Apply Discount</a>';
if ( ! WC()->cart->has_discount( $discount ) ) {
	wc_add_notice( $message, 'success' );
}