/**
 * An endpoint that accepts XML in request body.
 * 
 * Description of the endpoint.
 * 
 * @request-body string
 * @request-header Content-Type {type: 'application/xml'}
 */
public function process(): array
{
    $xml = simplexml_load_string(file_get_contents('php://input'));

    if (! $xml) {
        return ['error' => 'Invalid XML'];
    }

    return array_map(function ($order) {
        $amount = (float) $order->amount;

        return [
            'customer' => $order->customer,
            'amount' => $amount,
            'points' => $amount > 1000 ? 10 : 1,
        ];
    }, (array) $xml->order);
}