class Language

class Language extends CKEditorPluginBase implements CKEditorPluginConfigurableInterface, CKEditorPluginCssInterface {
    
    /**
     * {@inheritdoc}
     */
    public function isInternal() {
        return TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFile() {
        // This plugin is already part of Drupal core's CKEditor build.
        return FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getLibraries(Editor $editor) {
        return [
            'ckeditor/drupal.ckeditor.plugins.language',
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getConfig(Editor $editor) {
        $language_list = [];
        $config = [
            'language_list' => 'un',
        ];
        $settings = $editor->getSettings();
        if (isset($settings['plugins']['language'])) {
            $config = $settings['plugins']['language'];
        }
        $predefined_languages = $config['language_list'] === 'all' ? LanguageManager::getStandardLanguageList() : LanguageManager::getUnitedNationsLanguageList();
        // Generate the language_list setting as expected by the CKEditor Language
        // plugin, but key the values by the full language name so that we can sort
        // them later on.
        foreach ($predefined_languages as $langcode => $language) {
            $english_name = $language[0];
            $direction = empty($language[2]) ? NULL : $language[2];
            if ($direction === LanguageInterface::DIRECTION_RTL) {
                $language_list[$english_name] = $langcode . ':' . $english_name . ':rtl';
            }
            else {
                $language_list[$english_name] = $langcode . ':' . $english_name;
            }
        }
        // Sort on full language name.
        ksort($language_list);
        $config = [
            'language_list' => array_values($language_list),
        ];
        return $config;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getButtons() {
        $label = $this->t('Language');
        return [
            'Language' => [
                'label' => $label,
                'image_alternative' => [
                    '#type' => 'inline_template',
                    '#template' => '<a href="#" class="cke-icon-only" role="button" title="' . $label . '" aria-label="' . $label . '"><span class="cke_button_icon cke_button__language_icon">' . $label . '</span></a>',
                ],
            ],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function settingsForm(array $form, FormStateInterface $form_state, Editor $editor) {
        // Defaults.
        $config = [
            'language_list' => 'un',
        ];
        $settings = $editor->getSettings();
        if (isset($settings['plugins']['language'])) {
            $config = $settings['plugins']['language'];
        }
        $predefined_languages = LanguageManager::getStandardLanguageList();
        $form['language_list'] = [
            '#title' => $this->t('Language list'),
            '#title_display' => 'invisible',
            '#type' => 'select',
            '#options' => [
                'un' => $this->t("United Nations' official languages"),
                'all' => $this->t('All @count languages', [
                    '@count' => count($predefined_languages),
                ]),
            ],
            '#default_value' => $config['language_list'],
            '#description' => $this->t('The list of languages to show in the language dropdown. The basic list will only show the <a href=":url">six official languages of the UN</a>. The extended list will show all @count languages that are available in Drupal.', [
                ':url' => 'https://www.un.org/en/sections/about-un/official-languages',
                '@count' => count($predefined_languages),
            ]),
            '#attached' => [
                'library' => [
                    'ckeditor/drupal.ckeditor.language.admin',
                ],
            ],
        ];
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCssFiles(Editor $editor) {
        return [
            drupal_get_path('module', 'ckeditor') . '/css/plugins/language/ckeditor.language.css',
        ];
    }

}