public function render(
        $language = 'en',
        array $libraries = array(),
        $callback = null,
        $api_key = null
    )
    {
        $otherParameters = array();

        if (!empty($libraries)) {
            $otherParameters['libraries'] = implode(',', $libraries);
        }

        $otherParameters['language'] = $language;

        // Google Maps API warning: NoApiKeys https://developers.google.com/maps/documentation/javascript/error-messages#no-api-keys
        if (!is_null($api_key)) {
            $otherParameters['key'] = $api_key;
        }

        $this->jsonBuilder
            ->reset()
            ->setValue('[other_params]', urldecode(http_build_query($otherParameters)));

        if ($callback !== null) {
            $this->jsonBuilder->setValue('[callback]', $callback, false);
        }

        $callbackFunction = 'load_ivory_google_map_api';
        $url = sprintf('//www.google.com/jsapi?callback=%s', $callbackFunction);
        $loader = sprintf('google.load("maps", "3", %s);', $this->jsonBuilder->build());

        $output = array();
        $output[] = '<script type="text/javascript">'.PHP_EOL;
        $output[] = sprintf('function %s () { %s };'.PHP_EOL, $callbackFunction, $loader);
        $output[] = '</script>'.PHP_EOL;
        $output[] = sprintf('<script type="text/javascript" src="%s"></script>'.PHP_EOL, $url);

        $this->loaded = true;

        return implode('', $output);
    }