class EnvironmentResolver

class EnvironmentResolver implements ResolverInterface {
    public function hasVariable(string $variableName) : bool {
        if (!Configuration::isEmpty($_SERVER[$variableName] ?? null)) {
            return true;
        }
        $env = getenv($variableName);
        if ($env === false) {
            return false;
        }
        return !Configuration::isEmpty($env);
    }
    
    /**
     * @psalm-suppress InvalidReturnStatement
     * @psalm-suppress InvalidReturnType
     */
    public function retrieveValue(string $variableName) {
        $value = getenv($variableName);
        if ($value === false) {
            $value = $_SERVER[$variableName] ?? null;
        }
        return $value;
    }

}