class Serializer

class Serializer extends StylePluginBase implements CacheableDependencyInterface {
    
    /**
     * {@inheritdoc}
     */
    protected $usesRowPlugin = TRUE;
    
    /**
     * {@inheritdoc}
     */
    protected $usesGrouping = FALSE;
    
    /**
     * The serializer which serializes the views result.
     *
     * @var \Symfony\Component\Serializer\Serializer
     */
    protected $serializer;
    
    /**
     * The available serialization formats.
     *
     * @var array
     */
    protected $formats = [];
    
    /**
     * The serialization format providers, keyed by format.
     *
     * @var string[]
     */
    protected $formatProviders;
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('serializer'), $container->getParameter('serializer.formats'), $container->getParameter('serializer.format_providers'));
    }
    
    /**
     * Constructs a Plugin object.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, SerializerInterface $serializer, array $serializer_formats, array $serializer_format_providers) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->definition = $plugin_definition + $configuration;
        $this->serializer = $serializer;
        $this->formats = $serializer_formats;
        $this->formatProviders = $serializer_format_providers;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function defineOptions() {
        $options = parent::defineOptions();
        $options['formats'] = [
            'default' => [],
        ];
        return $options;
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildOptionsForm(&$form, FormStateInterface $form_state) {
        parent::buildOptionsForm($form, $form_state);
        $form['formats'] = [
            '#type' => 'checkboxes',
            '#title' => $this->t('Accepted request formats'),
            '#description' => $this->t('Request formats that will be allowed in responses. If none are selected all formats will be allowed.'),
            '#options' => $this->getFormatOptions(),
            '#default_value' => $this->options['formats'],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitOptionsForm(&$form, FormStateInterface $form_state) {
        parent::submitOptionsForm($form, $form_state);
        $formats = $form_state->getValue([
            'style_options',
            'formats',
        ]);
        $form_state->setValue([
            'style_options',
            'formats',
        ], array_filter($formats));
    }
    
    /**
     * {@inheritdoc}
     */
    public function render() {
        $rows = [];
        // If the Data Entity row plugin is used, this will be an array of entities
        // which will pass through Serializer to one of the registered Normalizers,
        // which will transform it to arrays/scalars. If the Data field row plugin
        // is used, $rows will not contain objects and will pass directly to the
        // Encoder.
        foreach ($this->view->result as $row_index => $row) {
            $this->view->row_index = $row_index;
            $rows[] = $this->view->rowPlugin
                ->render($row);
        }
        unset($this->view->row_index);
        // Get the content type configured in the display or fallback to the
        // default.
        if (empty($this->view->live_preview)) {
            $content_type = $this->displayHandler
                ->getContentType();
        }
        else {
            $content_type = !empty($this->options['formats']) ? reset($this->options['formats']) : 'json';
        }
        return $this->serializer
            ->serialize($rows, $content_type, [
            'views_style_plugin' => $this,
        ]);
    }
    
    /**
     * Gets a list of all available formats that can be requested.
     *
     * This will return the configured formats, or all formats if none have been
     * selected.
     *
     * @return array
     *   An array of formats.
     */
    public function getFormats() {
        return $this->options['formats'];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCacheMaxAge() {
        return Cache::PERMANENT;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCacheContexts() {
        return [
            'request_format',
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCacheTags() {
        return [];
    }
    
    /**
     * {@inheritdoc}
     */
    public function calculateDependencies() {
        $dependencies = parent::calculateDependencies();
        $formats = $this->getFormats();
        $providers = array_intersect_key($this->formatProviders, array_flip($formats));
        // The plugin always uses services from the serialization module.
        $providers[] = 'serialization';
        $dependencies += [
            'module' => [],
        ];
        $dependencies['module'] = array_merge($dependencies['module'], $providers);
        return $dependencies;
    }
    
    /**
     * Returns an array of format options.
     *
     * @return string[]
     *   An array of format options. Both key and value are the same.
     */
    protected function getFormatOptions() {
        $formats = array_keys($this->formatProviders);
        return array_combine($formats, $formats);
    }

}