class JsonApiSettingsForm

class JsonApiSettingsForm extends ConfigFormBase {
    use RedundantEditableConfigNamesTrait;
    
    /**
     * {@inheritdoc}
     */
    public function getFormId() {
        return 'jsonapi_settings';
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildForm(array $form, FormStateInterface $form_state) {
        $form['read_only'] = [
            '#type' => 'radios',
            '#title' => $this->t('Allowed operations'),
            '#options' => [
                'r' => $this->t('Accept only JSON:API read operations.'),
                'rw' => $this->t('Accept all JSON:API create, read, update, and delete operations.'),
            ],
            '#config_target' => new ConfigTarget('jsonapi.settings', 'read_only', fn($value) => $value ? 'r' : 'rw', fn($value) => $value === 'r'),
            '#description' => $this->t('Warning: Only enable all operations if the site requires it. <a href=":docs">Learn more about securing your site with JSON:API.</a>', [
                ':docs' => 'https://www.drupal.org/docs/8/modules/jsonapi/security-considerations',
            ]),
        ];
        return parent::buildForm($form, $form_state);
    }

}