class View

class View extends ConfigEntityBase implements ViewEntityInterface {
    
    /**
     * The name of the base table this view will use.
     *
     * @var string
     */
    protected $base_table = 'node';
    
    /**
     * The unique ID of the view.
     *
     * @var string
     */
    protected $id = NULL;
    
    /**
     * The label of the view.
     *
     * @var string
     */
    protected $label;
    
    /**
     * The description of the view, which is used only in the interface.
     *
     * @var string
     */
    protected $description = '';
    
    /**
     * The "tags" of a view.
     *
     * The tags are stored as a single string, though it is used as multiple tags
     * for example in the views overview.
     *
     * @var string
     */
    protected $tag = '';
    
    /**
     * Stores all display handlers of this view.
     *
     * An array containing Drupal\views\Plugin\views\display\DisplayPluginBase
     * objects.
     *
     * @var array
     */
    protected $display = [];
    
    /**
     * The name of the base field to use.
     *
     * @var string
     */
    protected $base_field = 'nid';
    
    /**
     * Stores a reference to the executable version of this view.
     *
     * @var \Drupal\views\ViewExecutable
     */
    protected $executable;
    
    /**
     * The module implementing this view.
     *
     * @var string
     */
    protected $module = 'views';
    
    /**
     * {@inheritdoc}
     */
    public function getExecutable() {
        // Ensure that an executable View is available.
        if (!isset($this->executable)) {
            $this->executable = Views::executableFactory()->get($this);
        }
        return $this->executable;
    }
    
    /**
     * {@inheritdoc}
     */
    public function createDuplicate() {
        $duplicate = parent::createDuplicate();
        unset($duplicate->executable);
        return $duplicate;
    }
    
    /**
     * {@inheritdoc}
     */
    public function label() {
        return $this->get('label');
    }
    
    /**
     * {@inheritdoc}
     */
    public function addDisplay($plugin_id = 'page', $title = NULL, $id = NULL) {
        if (empty($plugin_id)) {
            return FALSE;
        }
        $plugin = Views::pluginManager('display')->getDefinition($plugin_id);
        if (empty($plugin)) {
            $plugin['title'] = t('Broken');
        }
        if (empty($id)) {
            $id = $this->generateDisplayId($plugin_id);
            // Generate a unique human-readable name by inspecting the counter at the
            // end of the previous display ID, e.g., 'page_1'.
            if ($id !== 'default') {
                preg_match("/[0-9]+/", $id, $count);
                $count = $count[0];
            }
            else {
                $count = '';
            }
            if (empty($title)) {
                // If there is no title provided, use the plugin title, and if there are
                // multiple displays, append the count.
                $title = $plugin['title'];
                if ($count > 1) {
                    $title .= ' ' . $count;
                }
            }
        }
        $display_options = [
            'display_plugin' => $plugin_id,
            'id' => $id,
            // Cast the display title to a string since it is an object.
            // @see \Drupal\Core\StringTranslation\TranslatableMarkup
'display_title' => (string) $title,
            'position' => $id === 'default' ? 0 : count($this->display),
            'display_options' => [],
        ];
        // Add the display options to the view.
        $this->display[$id] = $display_options;
        return $id;
    }
    
    /**
     * Generates a display ID of a certain plugin type.
     *
     * @param string $plugin_id
     *   Which plugin should be used for the new display ID.
     *
     * @return string
     */
    protected function generateDisplayId($plugin_id) {
        // 'default' is singular and is unique, so just go with 'default'
        // for it. For all others, start counting.
        if ($plugin_id == 'default') {
            return 'default';
        }
        // Initial ID.
        $id = $plugin_id . '_1';
        $count = 1;
        // Loop through IDs based upon our style plugin name until
        // we find one that is unused.
        while (!empty($this->display[$id])) {
            $id = $plugin_id . '_' . ++$count;
        }
        return $id;
    }
    
    /**
     * {@inheritdoc}
     */
    public function &getDisplay($display_id) {
        return $this->display[$display_id];
    }
    
    /**
     * {@inheritdoc}
     */
    public function duplicateDisplayAsType($old_display_id, $new_display_type) {
        $executable = $this->getExecutable();
        $display = $executable->newDisplay($new_display_type);
        $new_display_id = $display->display['id'];
        $displays = $this->get('display');
        // Let the display title be generated by the addDisplay method and set the
        // right display plugin, but keep the rest from the original display.
        $display_duplicate = $displays[$old_display_id];
        unset($display_duplicate['display_title']);
        unset($display_duplicate['display_plugin']);
        unset($display_duplicate['new_id']);
        $displays[$new_display_id] = NestedArray::mergeDeep($displays[$new_display_id], $display_duplicate);
        $displays[$new_display_id]['id'] = $new_display_id;
        // First set the displays.
        $this->set('display', $displays);
        // Ensure that we just copy display options, which are provided by the new
        // display plugin.
        $executable->setDisplay($new_display_id);
        $executable->display_handler
            ->filterByDefinedOptions($displays[$new_display_id]['display_options']);
        // Update the display settings.
        $this->set('display', $displays);
        return $new_display_id;
    }
    
    /**
     * {@inheritdoc}
     */
    public function calculateDependencies() {
        parent::calculateDependencies();
        // Ensure that the view is dependant on the module that implements the view.
        $this->addDependency('module', $this->module);
        $executable = $this->getExecutable();
        $executable->initDisplay();
        $executable->initStyle();
        foreach ($executable->displayHandlers as $display) {
            // Calculate the dependencies each display has.
            $this->calculatePluginDependencies($display);
        }
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function preSave(EntityStorageInterface $storage) {
        parent::preSave($storage);
        $displays = $this->get('display');
        // Sort the displays.
        ksort($displays);
        $this->set('display', [
            'default' => $displays['default'],
        ] + $displays);
        // Calculating the cacheability metadata is only needed when the view is
        // saved through the UI or API. It should not be done when we are syncing
        // configuration or installing modules.
        if (!$this->isSyncing() && !$this->hasTrustedData()) {
            $this->addCacheMetadata();
        }
    }
    
    /**
     * Fills in the cache metadata of this view.
     *
     * Cache metadata is set per view and per display, and ends up being stored in
     * the view's configuration. This allows Views to determine very efficiently:
     * - the max-age
     * - the cache contexts
     * - the cache tags
     *
     * In other words: this allows us to do the (expensive) work of initializing
     * Views plugins and handlers to determine their effect on the cacheability of
     * a view at save time rather than at runtime.
     */
    protected function addCacheMetadata() {
        $executable = $this->getExecutable();
        $current_display = $executable->current_display;
        $displays = $this->get('display');
        foreach (array_keys($displays) as $display_id) {
            $display =& $this->getDisplay($display_id);
            $executable->setDisplay($display_id);
            $cache_metadata = $executable->getDisplay()
                ->calculateCacheMetadata();
            $display['cache_metadata']['max-age'] = $cache_metadata->getCacheMaxAge();
            $display['cache_metadata']['contexts'] = $cache_metadata->getCacheContexts();
            $display['cache_metadata']['tags'] = $cache_metadata->getCacheTags();
            // Always include at least the 'languages:' context as there will most
            // probably be translatable strings in the view output.
            $display['cache_metadata']['contexts'] = Cache::mergeContexts($display['cache_metadata']['contexts'], [
                'languages:' . LanguageInterface::TYPE_INTERFACE,
            ]);
            sort($display['cache_metadata']['tags']);
            sort($display['cache_metadata']['contexts']);
        }
        // Restore the previous active display.
        $executable->setDisplay($current_display);
    }
    
    /**
     * {@inheritdoc}
     */
    public function postSave(EntityStorageInterface $storage, $update = TRUE) {
        parent::postSave($storage, $update);
        // @todo Remove if views implements a view_builder controller.
        views_invalidate_cache();
        $this->invalidateCaches();
        // Rebuild the router if this is a new view, or its status changed.
        if (!isset($this->original) || $this->status() != $this->original
            ->status()) {
            \Drupal::service('router.builder')->setRebuildNeeded();
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public static function postLoad(EntityStorageInterface $storage, array &$entities) {
        parent::postLoad($storage, $entities);
        foreach ($entities as $entity) {
            $entity->mergeDefaultDisplaysOptions();
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public static function preCreate(EntityStorageInterface $storage, array &$values) {
        parent::preCreate($storage, $values);
        // If there is no information about displays available add at least the
        // default display.
        $values += [
            'display' => [
                'default' => [
                    'display_plugin' => 'default',
                    'id' => 'default',
                    'display_title' => 'Default',
                    'position' => 0,
                    'display_options' => [],
                ],
            ],
        ];
    }
    
    /**
     * {@inheritdoc}
     */
    public function postCreate(EntityStorageInterface $storage) {
        parent::postCreate($storage);
        $this->mergeDefaultDisplaysOptions();
    }
    
    /**
     * {@inheritdoc}
     */
    public static function preDelete(EntityStorageInterface $storage, array $entities) {
        parent::preDelete($storage, $entities);
        // Call the remove() hook on the individual displays.
        
        /** @var \Drupal\views\ViewEntityInterface $entity */
        foreach ($entities as $entity) {
            $executable = Views::executableFactory()->get($entity);
            foreach ($entity->get('display') as $display_id => $display) {
                $executable->setDisplay($display_id);
                $executable->getDisplay()
                    ->remove();
            }
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public static function postDelete(EntityStorageInterface $storage, array $entities) {
        parent::postDelete($storage, $entities);
        $tempstore = \Drupal::service('tempstore.shared')->get('views');
        foreach ($entities as $entity) {
            $tempstore->delete($entity->id());
        }
        views_invalidate_cache();
    }
    
    /**
     * {@inheritdoc}
     */
    public function mergeDefaultDisplaysOptions() {
        $displays = [];
        foreach ($this->get('display') as $key => $options) {
            $options += [
                'display_options' => [],
                'display_plugin' => NULL,
                'id' => NULL,
                'display_title' => '',
                'position' => NULL,
            ];
            // Add the defaults for the display.
            $displays[$key] = $options;
        }
        $this->set('display', $displays);
    }
    
    /**
     * {@inheritdoc}
     */
    public function isInstallable() {
        $table_definition = \Drupal::service('views.views_data')->get($this->base_table);
        // Check whether the base table definition exists and contains a base table
        // definition. For example, taxonomy_views_data_alter() defines
        // node_field_data even if it doesn't exist as a base table.
        return $table_definition && isset($table_definition['table']['base']);
    }
    
    /**
     * {@inheritdoc}
     */
    public function __sleep() : array {
        $keys = parent::__sleep();
        unset($keys[array_search('executable', $keys)]);
        return $keys;
    }
    
    /**
     * Invalidates cache tags.
     */
    public function invalidateCaches() {
        // Invalidate cache tags for cached rows.
        $tags = $this->getCacheTags();
        \Drupal::service('cache_tags.invalidator')->invalidateTags($tags);
    }
    
    /**
     * {@inheritdoc}
     */
    public function onDependencyRemoval(array $dependencies) {
        $changed = FALSE;
        // Don't intervene if the views module is removed.
        if (isset($dependencies['module']) && in_array('views', $dependencies['module'])) {
            return FALSE;
        }
        // If the base table for the View is provided by a module being removed, we
        // delete the View because this is not something that can be fixed manually.
        $views_data = Views::viewsData();
        $base_table = $this->get('base_table');
        $base_table_data = $views_data->get($base_table);
        if (!empty($base_table_data['table']['provider']) && in_array($base_table_data['table']['provider'], $dependencies['module'])) {
            return FALSE;
        }
        $current_display = $this->getExecutable()->current_display;
        $handler_types = Views::getHandlerTypes();
        // Find all the handlers and check whether they want to do something on
        // dependency removal.
        foreach ($this->display as $display_id => $display_plugin_base) {
            $this->getExecutable()
                ->setDisplay($display_id);
            $display = $this->getExecutable()
                ->getDisplay();
            foreach (array_keys($handler_types) as $handler_type) {
                $handlers = $display->getHandlers($handler_type);
                foreach ($handlers as $handler_id => $handler) {
                    if ($handler instanceof DependentWithRemovalPluginInterface) {
                        if ($handler->onDependencyRemoval($dependencies)) {
                            // Remove the handler and indicate we made changes.
                            unset($this->display[$display_id]['display_options'][$handler_types[$handler_type]['plural']][$handler_id]);
                            $changed = TRUE;
                        }
                    }
                }
            }
        }
        // Disable the View if we made changes.
        // @todo https://www.drupal.org/node/2832558 Give better feedback for
        // disabled config.
        if ($changed) {
            // Force a recalculation of the dependencies if we made changes.
            $this->getExecutable()->current_display = NULL;
            $this->calculateDependencies();
            $this->disable();
        }
        $this->getExecutable()
            ->setDisplay($current_display);
        return $changed;
    }

}