class InfoForm

class InfoForm extends ConfigFormBase {
    use AdvaggSettersTrait;
    
    /**
     * The theme registry service.
     *
     * @var \Drupal\Core\Theme\Registry
     */
    protected $themeRegistry;
    
    /**
     * The request stack.
     *
     * @var \Symfony\Component\HttpFoundation\RequestStack
     */
    protected $requestStack;
    
    /**
     * The date formatter service.
     *
     * @var \Drupal\Core\Datetime\DateFormatterInterface
     */
    protected $dateFormatter;
    
    /**
     * The string translation service.
     *
     * @var \Drupal\Core\StringTranslation\Translator\TranslatorInterface
     */
    protected $translation;
    
    /**
     * The AdvAgg cache.
     *
     * @var \Drupal\Core\Cache\CacheBackendInterface
     */
    protected $cache;
    
    /**
     * The Messenger service.
     *
     * @var \Drupal\Core\Messenger\MessengerInterface
     */
    protected $messenger;
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        
        /**
         * @var \Drupal\advagg\Form\InfoForm
         */
        $instance = parent::create($container);
        $instance->setThemeRegistry($container->get('theme.registry'));
        $instance->setRequestStack($container->get('request_stack'));
        $instance->setDateFomatter($container->get('date.formatter'));
        $instance->setStringTranslation($container->get('string_translation'));
        $instance->setCache($container->get('cache.advagg'));
        return $instance;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'advagg_info';
    }
    
    /**
     * {@inheritdoc}
     */
    protected function getEditableConfigNames() {
        return [];
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        $form['tip'] = [
            '#markup' => '<p>' . $this->t('This page provides debugging information. There are no configuration options here.') . '</p>',
        ];
        // Get all hooks and variables.
        $core_hooks = $this->themeRegistry
            ->get();
        // Output html preprocess functions hooks.
        $form['theme_info'] = [
            '#type' => 'details',
            '#open' => TRUE,
            '#title' => $this->t('Hook Theme Info'),
        ];
        $data = implode("\n", $core_hooks['html']['preprocess functions']);
        $form['theme_info']['advagg_theme_info'] = [
            '#markup' => '<p>preprocess functions on html.</p><pre>' . $data . '</pre>',
        ];
        // Get info about a file.
        $form['get_info_about_agg'] = [
            '#type' => 'details',
            '#open' => TRUE,
            '#title' => $this->t('Get detailed info about an optimized file'),
        ];
        $form['get_info_about_agg']['filename'] = [
            '#type' => 'textfield',
            '#size' => 170,
            '#maxlength' => 256,
            '#default_value' => '',
            '#title' => $this->t('Filename'),
        ];
        $form['get_info_about_agg']['submit'] = [
            '#type' => 'submit',
            '#value' => $this->t('Lookup Details'),
            '#submit' => [
                '::getFileInfoSubmit',
            ],
            '#validate' => [
                '::getFileInfoValidate',
            ],
            '#ajax' => [
                'callback' => '::getFileInfoAjax',
                'wrapper' => 'advagg-file-info-ajax',
                'effect' => 'fade',
            ],
        ];
        if ($tip = $this->getRandomFile()) {
            $form['get_info_about_agg']['tip'] = [
                '#markup' => '<p>' . $this->t('Input an optimized filename like "@css_file".', [
                    '@css_file' => $tip,
                ]) . '</p>',
            ];
        }
        $form['get_info_about_agg']['wrapper'] = [
            '#prefix' => "<div id='advagg-file-info-ajax'>",
            '#suffix' => "</div>",
        ];
        $form = parent::buildForm($form, $form_state);
        unset($form['actions']);
        return $form;
    }
    
    /**
     * Format an indented list from array.
     *
     * @param array $list
     *   The array to convert to a string.
     * @param int $depth
     *   (optional) Depth multiplier for indentation.
     *
     * @return string
     *   The imploded and spaced array.
     */
    private function formatList(array $list, $depth = 1) {
        $spacer = '<br />' . str_repeat('&nbsp;', 2 * $depth);
        $output = $spacer . Xss::filter(implode($spacer, $list), [
            'br',
        ]);
        return $output;
    }
    
    /**
     * Display file info in a drupal message.
     *
     * @param array $form
     *   An associative array containing the structure of the form.
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     */
    public function getFileInfoSubmit(array &$form, FormStateInterface $form_state) {
        $this->messenger()
            ->addMessage($this->getFileInfo($form_state->getValue('filename')));
    }
    
    /**
     * Display file info via ajax callback.
     *
     * @param array $form
     *   An associative array containing the structure of the form.
     *
     * @return array
     *   The file info element.
     */
    public function getFileInfoAjax(array &$form) {
        return $form['get_info_about_agg']['wrapper'];
    }
    
    /**
     * Verify that the filename is correct.
     *
     * @param array $form
     *   An associative array containing the structure of the form.
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     */
    public function getFileInfoValidate(array $form, FormStateInterface $form_state) {
        if (empty($form_state->getValue('filename'))) {
            $form_state->setErrorByName('filename', $this->t('Please input a valid optimized filename.'));
        }
    }
    
    /**
     * Get detailed info about the given filename.
     *
     * @param string $filename
     *   Name of file to lookup.
     *
     * @return string
     *   Detailed info about this file.
     */
    private function getFileInfo($filename) {
        if (substr_compare($filename, 'css_', 0) || substr_compare($filename, 'js_', 0)) {
            $cid = str_replace([
                'css_',
                'js_',
                '.css',
                '.js',
            ], '', $filename);
            $cid = substr($cid, 0, strpos($cid, '.'));
            if ($cached = $this->cache
                ->get($cid, TRUE)) {
                return print_r($cached->data, TRUE);
            }
        }
        return $this->t('Optimized file information not found, confirm spelling of the path. Alternatively, that could be an outdated file.');
    }
    
    /**
     * Get a (pseudo) random optimized file name.
     *
     * @return bool|string
     *   The filename or FALSE if no valid files found.
     */
    private function getRandomFile() {
        // Ensure the directory exists.
        $dir = 'public://js/optimized/';
        if (!is_dir($dir)) {
            return FALSE;
        }
        if ($handler = opendir($dir)) {
            while (($file = readdir($handler)) !== FALSE) {
                if (is_file($dir . $file) && pathinfo($file, PATHINFO_EXTENSION) == 'js') {
                    closedir($handler);
                    return $file;
                }
            }
            closedir($handler);
        }
        return FALSE;
    }

}