class SettingsForm

class SettingsForm extends ConfigFormBase {
    
    /**
     * The AdvAgg cache.
     *
     * @var \Drupal\Core\Cache\CacheBackendInterface
     */
    protected $cache;
    
    /**
     * Constructs a SettingsForm object.
     *
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The factory for configuration objects.
     * @param \Drupal\Core\Cache\CacheBackendInterface $cache
     *   The AdvAgg cache service.
     */
    public function __construct(ConfigFactoryInterface $config_factory, CacheBackendInterface $cache) {
        parent::__construct($config_factory);
        $this->cache = $cache;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('config.factory'), $container->get('cache.advagg'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'advagg_bundler_settings';
    }
    
    /**
     * {@inheritdoc}
     */
    protected function getEditableConfigNames() {
        return [
            'advagg_bundler.settings',
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        
        /** @var \Drupal\Core\Config\Config $config */
        $config = $this->config('advagg_bundler.settings');
        $form['active'] = [
            '#type' => 'checkbox',
            '#title' => $this->t('Bundler is Active'),
            '#default_value' => $config->get('active'),
            '#description' => $this->t('If not checked, the bundler will not split up aggregates.'),
        ];
        $options = [
            0 => 0,
            1 => 1,
            2 => 2,
            3 => 3,
            4 => 4,
            5 => 5,
            6 => 6,
            7 => 7,
            8 => 8,
            9 => 9,
            10 => 10,
            11 => 11,
            12 => 12,
            13 => 13,
            14 => 14,
            15 => 15,
        ];
        $form['css'] = [
            '#type' => 'fieldset',
            '#title' => $this->t('CSS Bundling options.'),
        ];
        $form['css']['max_css'] = [
            '#type' => 'select',
            '#title' => $this->t('Target Number Of CSS Bundles Per Page'),
            '#default_value' => $config->get('css.max'),
            '#options' => $options,
            '#description' => $this->t('If 0 is selected then the bundler is disabled'),
            '#states' => [
                'disabled' => [
                    '#edit-active' => [
                        'checked' => FALSE,
                    ],
                ],
            ],
        ];
        $form['css']['css_logic'] = [
            '#type' => 'radios',
            '#title' => $this->t('Grouping logic'),
            '#default_value' => $config->get('css.logic'),
            '#options' => [
                0 => $this->t('File count'),
                1 => $this->t('File size'),
            ],
            '#description' => $this->t('If file count is selected then each bundle will try to have a similar number of original files aggregated inside of it. If file size is selected then each bundle will try to have a similar file size.'),
            '#states' => [
                'disabled' => [
                    '#edit-active' => [
                        'checked' => FALSE,
                    ],
                ],
            ],
        ];
        $form['js'] = [
            '#type' => 'fieldset',
            '#title' => $this->t('JavaScript Bundling options.'),
        ];
        $form['js']['max_js'] = [
            '#type' => 'select',
            '#title' => $this->t('Target Number Of JS Bundles Per Page'),
            '#default_value' => $config->get('js.max'),
            '#options' => $options,
            '#description' => $this->t('If 0 is selected then the bundler is disabled'),
            '#states' => [
                'disabled' => [
                    '#edit-active' => [
                        'checked' => FALSE,
                    ],
                ],
            ],
        ];
        $form['js']['js_logic'] = [
            '#type' => 'radios',
            '#title' => $this->t('Grouping logic'),
            '#default_value' => $config->get('js.logic'),
            '#options' => [
                0 => $this->t('File count'),
                1 => $this->t('File size'),
            ],
            '#description' => $this->t('If file count is selected then each bundle will try to have a similar number of original files aggregated inside of it. If file size is selected then each bundle will try to have a similar file size.'),
            '#states' => [
                'disabled' => [
                    '#edit-active' => [
                        'checked' => FALSE,
                    ],
                ],
            ],
        ];
        return parent::buildForm($form, $form_state);
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        
        /** @var \Drupal\Core\Config\Config $config */
        $config = $this->config('advagg_bundler.settings')
            ->set('active', $form_state->getValue('active'))
            ->set('css.max', $form_state->getValue('max_css'))
            ->set('css.logic', $form_state->getValue('css_logic'))
            ->set('js.max', $form_state->getValue('max_js'))
            ->set('js.logic', $form_state->getValue('js_logic'));
        $config->save();
        // Clear Caches.
        Cache::invalidateTags([
            'library_info',
        ]);
        $this->cache
            ->invalidateAll();
        parent::submitForm($form, $form_state);
    }

}