class LayoutBuilderEntityViewDisplay

class LayoutBuilderEntityViewDisplay extends BaseEntityViewDisplay implements LayoutEntityDisplayInterface {
    use LayoutEntityHelperTrait;
    use SectionListTrait;
    
    /**
     * The entity field manager.
     *
     * @var \Drupal\Core\Entity\EntityFieldManagerInterface
     */
    protected $entityFieldManager;
    
    /**
     * {@inheritdoc}
     */
    public function __construct(array $values, $entity_type) {
        // Set $entityFieldManager before calling the parent constructor because the
        // constructor will call init() which then calls setComponent() which needs
        // $entityFieldManager.
        $this->entityFieldManager = \Drupal::service('entity_field.manager');
        parent::__construct($values, $entity_type);
    }
    
    /**
     * {@inheritdoc}
     */
    public function isOverridable() {
        return $this->isLayoutBuilderEnabled() && $this->getThirdPartySetting('layout_builder', 'allow_custom', FALSE);
    }
    
    /**
     * {@inheritdoc}
     */
    public function setOverridable($overridable = TRUE) {
        $this->setThirdPartySetting('layout_builder', 'allow_custom', $overridable);
        // Enable Layout Builder if it's not already enabled and overriding.
        if ($overridable && !$this->isLayoutBuilderEnabled()) {
            $this->enableLayoutBuilder();
        }
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function isLayoutBuilderEnabled() {
        // Layout Builder must not be enabled for the '_custom' view mode that is
        // used for on-the-fly rendering of fields in isolation from the entity.
        if ($this->isCustomMode()) {
            return FALSE;
        }
        return (bool) $this->getThirdPartySetting('layout_builder', 'enabled');
    }
    
    /**
     * {@inheritdoc}
     */
    public function enableLayoutBuilder() {
        $this->setThirdPartySetting('layout_builder', 'enabled', TRUE);
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function disableLayoutBuilder() {
        $this->setOverridable(FALSE);
        $this->setThirdPartySetting('layout_builder', 'enabled', FALSE);
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getSections() {
        return $this->getThirdPartySetting('layout_builder', 'sections', []);
    }
    
    /**
     * {@inheritdoc}
     */
    protected function setSections(array $sections) {
        // Third-party settings must be completely unset instead of stored as an
        // empty array.
        if (!$sections) {
            $this->unsetThirdPartySetting('layout_builder', 'sections');
        }
        else {
            $this->setThirdPartySetting('layout_builder', 'sections', array_values($sections));
        }
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function preSave(EntityStorageInterface $storage) {
        $original_value = isset($this->original) ? $this->original
            ->isOverridable() : FALSE;
        $new_value = $this->isOverridable();
        if ($original_value !== $new_value) {
            $entity_type_id = $this->getTargetEntityTypeId();
            $bundle = $this->getTargetBundle();
            if ($new_value) {
                $this->addSectionField($entity_type_id, $bundle, OverridesSectionStorage::FIELD_NAME);
            }
            else {
                $this->removeSectionField($entity_type_id, $bundle, OverridesSectionStorage::FIELD_NAME);
            }
        }
        parent::preSave($storage);
        $already_enabled = isset($this->original) ? $this->original
            ->isLayoutBuilderEnabled() : FALSE;
        $set_enabled = $this->isLayoutBuilderEnabled();
        if ($already_enabled !== $set_enabled) {
            if ($set_enabled) {
                // Loop through all existing field-based components and add them as
                // section-based components.
                $components = $this->getComponents();
                // Sort the components by weight.
                uasort($components, 'Drupal\\Component\\Utility\\SortArray::sortByWeightElement');
                foreach ($components as $name => $component) {
                    $this->setComponent($name, $component);
                }
            }
            else {
                // When being disabled, remove all existing section data.
                $this->removeAllSections();
            }
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function save() : int {
        $return = parent::save();
        if (!\Drupal::moduleHandler()->moduleExists('layout_builder_expose_all_field_blocks')) {
            // Invalidate the block cache in order to regenerate field block
            // definitions.
            \Drupal::service('plugin.manager.block')->clearCachedDefinitions();
        }
        return $return;
    }
    
    /**
     * Removes a layout section field if it is no longer needed.
     *
     * Because the field is shared across all view modes, the field will only be
     * removed if no other view modes are using it.
     *
     * @param string $entity_type_id
     *   The entity type ID.
     * @param string $bundle
     *   The bundle.
     * @param string $field_name
     *   The name for the layout section field.
     */
    protected function removeSectionField($entity_type_id, $bundle, $field_name) {
        
        /** @var \Drupal\Core\Config\Entity\ConfigEntityStorageInterface $storage */
        $storage = $this->entityTypeManager()
            ->getStorage($this->getEntityTypeId());
        $query = $storage->getQuery()
            ->condition('targetEntityType', $this->getTargetEntityTypeId())
            ->condition('bundle', $this->getTargetBundle())
            ->condition('mode', $this->getMode(), '<>')
            ->condition('third_party_settings.layout_builder.allow_custom', TRUE);
        $enabled = (bool) $query->count()
            ->execute();
        if (!$enabled && ($field = FieldConfig::loadByName($entity_type_id, $bundle, $field_name))) {
            $field->delete();
        }
    }
    
    /**
     * Adds a layout section field to a given bundle.
     *
     * @param string $entity_type_id
     *   The entity type ID.
     * @param string $bundle
     *   The bundle.
     * @param string $field_name
     *   The name for the layout section field.
     */
    protected function addSectionField($entity_type_id, $bundle, $field_name) {
        $field = FieldConfig::loadByName($entity_type_id, $bundle, $field_name);
        if (!$field) {
            $field_storage = FieldStorageConfig::loadByName($entity_type_id, $field_name);
            if (!$field_storage) {
                $field_storage = FieldStorageConfig::create([
                    'entity_type' => $entity_type_id,
                    'field_name' => $field_name,
                    'type' => 'layout_section',
                    'locked' => TRUE,
                ]);
                $field_storage->setTranslatable(FALSE);
                $field_storage->save();
            }
            $field = FieldConfig::create([
                'field_storage' => $field_storage,
                'bundle' => $bundle,
                'label' => t('Layout'),
            ]);
            $field->setTranslatable(FALSE);
            $field->save();
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function createCopy($mode) {
        // Disable Layout Builder and remove any sections copied from the original.
        return parent::createCopy($mode)->setSections([])
            ->disableLayoutBuilder();
    }
    
    /**
     * {@inheritdoc}
     */
    protected function getDefaultRegion() {
        if ($this->hasSection(0)) {
            return $this->getSection(0)
                ->getDefaultRegion();
        }
        return parent::getDefaultRegion();
    }
    
    /**
     * Wraps the context repository service.
     *
     * @return \Drupal\Core\Plugin\Context\ContextRepositoryInterface
     *   The context repository service.
     */
    protected function contextRepository() {
        return \Drupal::service('context.repository');
    }
    
    /**
     * Indicates if this display is using the '_custom' view mode.
     *
     * @return bool
     *   TRUE if this display is using the '_custom' view mode, FALSE otherwise.
     */
    protected function isCustomMode() {
        return $this->getOriginalMode() === static::CUSTOM_MODE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildMultiple(array $entities) {
        $build_list = parent::buildMultiple($entities);
        // Layout Builder can not be enabled for the '_custom' view mode that is
        // used for on-the-fly rendering of fields in isolation from the entity.
        if ($this->isCustomMode()) {
            return $build_list;
        }
        foreach ($entities as $id => $entity) {
            $build_list[$id]['_layout_builder'] = $this->buildSections($entity);
            // If there are any sections, remove all fields with configurable display
            // from the existing build. These fields are replicated within sections as
            // field blocks by ::setComponent().
            if (!Element::isEmpty($build_list[$id]['_layout_builder'])) {
                foreach ($build_list[$id] as $name => $build_part) {
                    $field_definition = $this->getFieldDefinition($name);
                    if ($field_definition && $field_definition->isDisplayConfigurable($this->displayContext)) {
                        unset($build_list[$id][$name]);
                    }
                }
            }
        }
        return $build_list;
    }
    
    /**
     * Builds the render array for the sections of a given entity.
     *
     * @param \Drupal\Core\Entity\FieldableEntityInterface $entity
     *   The entity.
     *
     * @return array
     *   The render array representing the sections of the entity.
     */
    protected function buildSections(FieldableEntityInterface $entity) {
        $contexts = $this->getContextsForEntity($entity);
        $label = new TranslatableMarkup('@entity being viewed', [
            '@entity' => $entity->getEntityType()
                ->getSingularLabel(),
        ]);
        $contexts['layout_builder.entity'] = EntityContext::fromEntity($entity, $label);
        $cacheability = new CacheableMetadata();
        $storage = $this->sectionStorageManager()
            ->findByContext($contexts, $cacheability);
        $build = [];
        if ($storage) {
            foreach ($storage->getSections() as $delta => $section) {
                $build[$delta] = $section->toRenderArray($contexts);
            }
        }
        // The render array is built based on decisions made by SectionStorage
        // plugins and therefore it needs to depend on the accumulated
        // cacheability of those decisions.
        $cacheability->applyTo($build);
        return $build;
    }
    
    /**
     * Gets the available contexts for a given entity.
     *
     * @param \Drupal\Core\Entity\FieldableEntityInterface $entity
     *   The entity.
     *
     * @return \Drupal\Core\Plugin\Context\ContextInterface[]
     *   An array of context objects for a given entity.
     */
    protected function getContextsForEntity(FieldableEntityInterface $entity) {
        $available_context_ids = array_keys($this->contextRepository()
            ->getAvailableContexts());
        return [
            'view_mode' => new Context(ContextDefinition::create('string'), $this->getMode()),
            'entity' => EntityContext::fromEntity($entity),
            'display' => EntityContext::fromEntity($this),
        ] + $this->contextRepository()
            ->getRuntimeContexts($available_context_ids);
    }
    
    /**
     * {@inheritdoc}
     *
     * @todo Move this upstream in https://www.drupal.org/node/2939931.
     */
    public function label() {
        $bundle_info = \Drupal::service('entity_type.bundle.info')->getBundleInfo($this->getTargetEntityTypeId());
        $bundle_label = $bundle_info[$this->getTargetBundle()]['label'];
        $target_entity_type = $this->entityTypeManager()
            ->getDefinition($this->getTargetEntityTypeId());
        return new TranslatableMarkup('@bundle @label', [
            '@bundle' => $bundle_label,
            '@label' => $target_entity_type->getPluralLabel(),
        ]);
    }
    
    /**
     * {@inheritdoc}
     */
    public function calculateDependencies() {
        parent::calculateDependencies();
        foreach ($this->getSections() as $section) {
            $this->calculatePluginDependencies($section->getLayout());
            foreach ($section->getComponents() as $component) {
                $this->calculatePluginDependencies($component->getPlugin());
            }
        }
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public function onDependencyRemoval(array $dependencies) {
        $changed = parent::onDependencyRemoval($dependencies);
        // Loop through all sections and determine if the removed dependencies are
        // used by their layout plugins.
        foreach ($this->getSections() as $delta => $section) {
            $layout_dependencies = $this->getPluginDependencies($section->getLayout());
            $layout_removed_dependencies = $this->getPluginRemovedDependencies($layout_dependencies, $dependencies);
            if ($layout_removed_dependencies) {
                // @todo Allow the plugins to react to their dependency removal in
                //   https://www.drupal.org/project/drupal/issues/2579743.
                $this->removeSection($delta);
                $changed = TRUE;
            }
            else {
                foreach ($section->getComponents() as $uuid => $component) {
                    $plugin_dependencies = $this->getPluginDependencies($component->getPlugin());
                    $component_removed_dependencies = $this->getPluginRemovedDependencies($plugin_dependencies, $dependencies);
                    if ($component_removed_dependencies) {
                        // @todo Allow the plugins to react to their dependency removal in
                        //   https://www.drupal.org/project/drupal/issues/2579743.
                        $section->removeComponent($uuid);
                        $changed = TRUE;
                    }
                }
            }
        }
        return $changed;
    }
    
    /**
     * {@inheritdoc}
     */
    public function setComponent($name, array $options = []) {
        parent::setComponent($name, $options);
        // Only continue if Layout Builder is enabled.
        if (!$this->isLayoutBuilderEnabled()) {
            return $this;
        }
        // Retrieve the updated options after the parent:: call.
        $options = $this->content[$name];
        // Provide backwards compatibility by converting to a section component.
        $field_definition = $this->getFieldDefinition($name);
        $extra_fields = $this->entityFieldManager
            ->getExtraFields($this->getTargetEntityTypeId(), $this->getTargetBundle());
        $is_view_configurable_non_extra_field = $field_definition && $field_definition->isDisplayConfigurable('view') && isset($options['type']);
        if ($is_view_configurable_non_extra_field || isset($extra_fields['display'][$name])) {
            $configuration = [
                'label_display' => '0',
                'context_mapping' => [
                    'entity' => 'layout_builder.entity',
                ],
            ];
            if ($is_view_configurable_non_extra_field) {
                $configuration['id'] = 'field_block:' . $this->getTargetEntityTypeId() . ':' . $this->getTargetBundle() . ':' . $name;
                $keys = array_flip([
                    'type',
                    'label',
                    'settings',
                    'third_party_settings',
                ]);
                $configuration['formatter'] = array_intersect_key($options, $keys);
            }
            else {
                $configuration['id'] = 'extra_field_block:' . $this->getTargetEntityTypeId() . ':' . $this->getTargetBundle() . ':' . $name;
            }
            $section = $this->getDefaultSection();
            $region = $options['region'] ?? $section->getDefaultRegion();
            $new_component = new SectionComponent(\Drupal::service('uuid')->generate(), $region, $configuration);
            $section->appendComponent($new_component);
        }
        return $this;
    }
    
    /**
     * Gets a default section.
     *
     * @return \Drupal\layout_builder\Section
     *   The default section.
     */
    protected function getDefaultSection() {
        // If no section exists, append a new one.
        if (!$this->hasSection(0)) {
            $this->appendSection(new Section('layout_onecol'));
        }
        // Return the first section.
        return $this->getSection(0);
    }
    
    /**
     * Gets the section storage manager.
     *
     * @return \Drupal\layout_builder\SectionStorage\SectionStorageManagerInterface
     *   The section storage manager.
     */
    private function sectionStorageManager() {
        return \Drupal::service('plugin.manager.layout_builder.section_storage');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getComponent($name) {
        if ($this->isLayoutBuilderEnabled() && ($section_component = $this->getSectionComponentForFieldName($name))) {
            $plugin = $section_component->getPlugin();
            if ($plugin instanceof ConfigurableInterface) {
                $configuration = $plugin->getConfiguration();
                if (isset($configuration['formatter'])) {
                    return $configuration['formatter'];
                }
            }
        }
        return parent::getComponent($name);
    }
    
    /**
     * Gets the component for a given field name if any.
     *
     * @param string $field_name
     *   The field name.
     *
     * @return \Drupal\layout_builder\SectionComponent|null
     *   The section component if it is available.
     */
    private function getSectionComponentForFieldName($field_name) {
        // Loop through every component until the first match is found.
        foreach ($this->getSections() as $section) {
            foreach ($section->getComponents() as $component) {
                $plugin = $component->getPlugin();
                if ($plugin instanceof DerivativeInspectionInterface && in_array($plugin->getBaseId(), [
                    'field_block',
                    'extra_field_block',
                ], TRUE)) {
                    // FieldBlock derivative IDs are in the format
                    // [entity_type]:[bundle]:[field].
                    [
                        ,
                        ,
                        $field_block_field_name,
                    ] = explode(PluginBase::DERIVATIVE_SEPARATOR, $plugin->getDerivativeId());
                    if ($field_block_field_name === $field_name) {
                        return $component;
                    }
                }
            }
        }
        return NULL;
    }

}