class CommentHooks

class CommentHooks {
    
    /**
     * Implements hook_help().
     */
    public function help($route_name, RouteMatchInterface $route_match) {
        switch ($route_name) {
            case 'help.page.comment':
                $output = '<h2>' . t('About') . '</h2>';
                $output .= '<p>' . t('The Comment module allows users to comment on site content, set commenting defaults and permissions, and moderate comments. For more information, see the <a href=":comment">online documentation for the Comment module</a>.', [
                    ':comment' => 'https://www.drupal.org/documentation/modules/comment',
                ]) . '</p>';
                $output .= '<h2>' . t('Uses') . '</h2>';
                $output .= '<dl>';
                $output .= '<dt>' . t('Enabling commenting') . '</dt>';
                $output .= '<dd>' . t('Comment functionality can be enabled for any entity sub-type (for example, a <a href=":content-type">content type</a>) by adding a <em>Comments</em> field on its <em>Manage fields page</em>. Adding or removing commenting for an entity through the user interface requires the <a href=":field_ui">Field UI</a> module to be installed, even though the commenting functionality works without it. For more information on fields and entities, see the <a href=":field">Field module help page</a>.', [
                    ':content-type' => \Drupal::moduleHandler()->moduleExists('node') ? Url::fromRoute('entity.node_type.collection')->toString() : '#',
                    ':field' => Url::fromRoute('help.page', [
                        'name' => 'field',
                    ])->toString(),
                    ':field_ui' => \Drupal::moduleHandler()->moduleExists('field_ui') ? Url::fromRoute('help.page', [
                        'name' => 'field_ui',
                    ])->toString() : '#',
                ]) . '</dd>';
                $output .= '<dt>' . t('Configuring commenting settings') . '</dt>';
                $output .= '<dd>' . t('Commenting settings can be configured by editing the <em>Comments</em> field on the <em>Manage fields page</em> of an entity type if the <em>Field UI module</em> is installed. Configuration includes the label of the comments field, the number of comments to be displayed, and whether they are shown in threaded list. Commenting can be configured as: <em>Open</em> to allow new comments, <em>Closed</em> to view existing comments, but prevent new comments, or <em>Hidden</em> to hide existing comments and prevent new comments. Changing this configuration for an entity type will not change existing entity items.') . '</dd>';
                $output .= '<dt>' . t('Overriding default settings') . '</dt>';
                $output .= '<dd>' . t('Users with the appropriate permissions can override the default commenting settings of an entity type when they create an item of that type.') . '</dd>';
                $output .= '<dt>' . t('Adding comment types') . '</dt>';
                $output .= '<dd>' . t('Additional <em>comment types</em> can be created per entity sub-type and added on the <a href=":field">Comment types page</a>. If there are multiple comment types available you can select the appropriate one after adding a <em>Comments field</em>.', [
                    ':field' => Url::fromRoute('entity.comment_type.collection')->toString(),
                ]) . '</dd>';
                $output .= '<dt>' . t('Approving and managing comments') . '</dt>';
                $output .= '<dd>' . t('Comments from users who have the <em>Skip comment approval</em> permission are published immediately. All other comments are placed in the <a href=":comment-approval">Unapproved comments</a> queue, until a user who has permission to <em>Administer comments and comment settings</em> publishes or deletes them. Published comments can be bulk managed on the <a href=":admin-comment">Published comments</a> administration page. When a comment has no replies, it remains editable by its author, as long as the author has <em>Edit own comments</em> permission.', [
                    ':comment-approval' => Url::fromRoute('comment.admin_approval')->toString(),
                    ':admin-comment' => Url::fromRoute('comment.admin')->toString(),
                ]) . '</dd>';
                $output .= '</dl>';
                return $output;
            case 'entity.comment_type.collection':
                $output = '<p>' . t('This page provides a list of all comment types on the site and allows you to manage the fields, form and display settings for each.') . '</p>';
                return $output;
        }
    }
    
    /**
     * Implements hook_entity_extra_field_info().
     */
    public function entityExtraFieldInfo() {
        $return = [];
        foreach (CommentType::loadMultiple() as $comment_type) {
            $return['comment'][$comment_type->id()] = [
                'form' => [
                    'author' => [
                        'label' => t('Author'),
                        'description' => t('Author textfield'),
                        'weight' => -2,
                    ],
                ],
            ];
            $return['comment'][$comment_type->id()]['display']['links'] = [
                'label' => t('Links'),
                'description' => t('Comment operation links'),
                'weight' => 100,
                'visible' => TRUE,
            ];
        }
        return $return;
    }
    
    /**
     * Implements hook_theme().
     */
    public function theme() : array {
        return [
            'comment' => [
                'render element' => 'elements',
            ],
            'field__comment' => [
                'base hook' => 'field',
            ],
        ];
    }
    
    /**
     * Implements hook_ENTITY_TYPE_create() for 'field_config'.
     */
    public function fieldConfigCreate(FieldConfigInterface $field) {
        if ($field->getType() == 'comment' && !$field->isSyncing()) {
            // Assign default values for the field.
            $default_value = $field->getDefaultValueLiteral();
            $default_value += [
                [],
            ];
            $default_value[0] += [
                'status' => CommentItemInterface::OPEN,
                'cid' => 0,
                'last_comment_timestamp' => 0,
                'last_comment_name' => '',
                'last_comment_uid' => 0,
                'comment_count' => 0,
            ];
            $field->setDefaultValue($default_value);
        }
    }
    
    /**
     * Implements hook_ENTITY_TYPE_update() for 'field_config'.
     */
    public function fieldConfigUpdate(FieldConfigInterface $field) {
        if ($field->getType() == 'comment') {
            // Comment field settings also affects the rendering of *comment* entities,
            // not only the *commented* entities.
            \Drupal::entityTypeManager()->getViewBuilder('comment')
                ->resetCache();
        }
    }
    
    /**
     * Implements hook_ENTITY_TYPE_insert() for 'field_storage_config'.
     */
    public function fieldStorageConfigInsert(FieldStorageConfigInterface $field_storage) {
        if ($field_storage->getType() == 'comment') {
            // Check that the target entity type uses an integer ID.
            $entity_type_id = $field_storage->getTargetEntityTypeId();
            if (!_comment_entity_uses_integer_id($entity_type_id)) {
                throw new \UnexpectedValueException('You cannot attach a comment field to an entity with a non-integer ID field');
            }
        }
    }
    
    /**
     * Implements hook_ENTITY_TYPE_delete() for 'field_config'.
     */
    public function fieldConfigDelete(FieldConfigInterface $field) {
        if ($field->getType() == 'comment') {
            // Delete all comments that used by the entity bundle.
            $entity_query = \Drupal::entityQuery('comment')->accessCheck(FALSE);
            $entity_query->condition('entity_type', $field->getEntityTypeId());
            $entity_query->condition('field_name', $field->getName());
            $cids = $entity_query->execute();
            $comment_storage = \Drupal::entityTypeManager()->getStorage('comment');
            $comments = $comment_storage->loadMultiple($cids);
            $comment_storage->delete($comments);
        }
    }
    
    /**
     * Implements hook_node_links_alter().
     */
    public function nodeLinksAlter(array &$links, NodeInterface $node, array &$context) {
        // Comment links are only added to node entity type for backwards
        // compatibility. Should you require comment links for other entity types you
        // can do so by implementing a new field formatter.
        // @todo Make this configurable from the formatter. See
        //   https://www.drupal.org/node/1901110.
        $comment_links = \Drupal::service('comment.link_builder')->buildCommentedEntityLinks($node, $context);
        $links += $comment_links;
    }
    
    /**
     * Implements hook_entity_view().
     */
    public function entityView(array &$build, EntityInterface $entity, EntityViewDisplayInterface $display, $view_mode) {
        if ($entity instanceof FieldableEntityInterface && $view_mode == 'rss' && $display->getComponent('links')) {
            
            /** @var \Drupal\comment\CommentManagerInterface $comment_manager */
            $comment_manager = \Drupal::service('comment.manager');
            $fields = $comment_manager->getFields($entity->getEntityTypeId());
            foreach ($fields as $field_name => $detail) {
                if ($entity->hasField($field_name) && $entity->get($field_name)->status != CommentItemInterface::HIDDEN) {
                    // Add a comments RSS element which is a URL to the comments of this
                    // entity.
                    $options = [
                        'fragment' => 'comments',
                        'absolute' => TRUE,
                    ];
                    $entity->rss_elements[] = [
                        'key' => 'comments',
                        'value' => $entity->toUrl('canonical', $options)
                            ->toString(),
                    ];
                }
            }
        }
    }
    
    /**
     * Implements hook_ENTITY_TYPE_view_alter() for node entities.
     */
    public function nodeViewAlter(array &$build, EntityInterface $node, EntityViewDisplayInterface $display) {
        if (\Drupal::moduleHandler()->moduleExists('history')) {
            $build['#attributes']['data-history-node-id'] = $node->id();
        }
    }
    
    /**
     * Implements hook_form_FORM_ID_alter() for field_ui_field_storage_add_form.
     */
    public function formFieldUiFieldStorageAddFormAlter(&$form, FormStateInterface $form_state) : void {
        $route_match = \Drupal::routeMatch();
        if ($form_state->get('entity_type_id') == 'comment' && $route_match->getParameter('commented_entity_type')) {
            $form['#title'] = \Drupal::service('comment.manager')->getFieldUIPageTitle($route_match->getParameter('commented_entity_type'), $route_match->getParameter('field_name'));
        }
    }
    
    /**
     * Implements hook_field_info_entity_type_ui_definitions_alter().
     */
    public function fieldInfoEntityTypeUiDefinitionsAlter(array &$ui_definitions, string $entity_type_id) {
        if (!_comment_entity_uses_integer_id($entity_type_id)) {
            unset($ui_definitions['comment']);
        }
    }
    
    /**
     * Implements hook_form_FORM_ID_alter().
     */
    public function formFieldUiFormDisplayOverviewFormAlter(&$form, FormStateInterface $form_state) : void {
        $route_match = \Drupal::routeMatch();
        if ($form['#entity_type'] == 'comment' && $route_match->getParameter('commented_entity_type')) {
            $form['#title'] = \Drupal::service('comment.manager')->getFieldUIPageTitle($route_match->getParameter('commented_entity_type'), $route_match->getParameter('field_name'));
        }
    }
    
    /**
     * Implements hook_form_FORM_ID_alter().
     */
    public function formFieldUiDisplayOverviewFormAlter(&$form, FormStateInterface $form_state) : void {
        $route_match = \Drupal::routeMatch();
        if ($form['#entity_type'] == 'comment' && $route_match->getParameter('commented_entity_type')) {
            $form['#title'] = \Drupal::service('comment.manager')->getFieldUIPageTitle($route_match->getParameter('commented_entity_type'), $route_match->getParameter('field_name'));
        }
    }
    
    /**
     * Implements hook_entity_storage_load().
     *
     * @see \Drupal\comment\Plugin\Field\FieldType\CommentItem::propertyDefinitions()
     */
    public function entityStorageLoad($entities, $entity_type) {
        // Comments can only be attached to content entities, so skip others.
        if (!\Drupal::entityTypeManager()->getDefinition($entity_type)
            ->entityClassImplements(FieldableEntityInterface::class)) {
            return;
        }
        if (!\Drupal::service('comment.manager')->getFields($entity_type)) {
            // Do not query database when entity has no comment fields.
            return;
        }
        // Load comment information from the database and update the entity's
        // comment statistics properties, which are defined on each CommentItem field.
        $result = \Drupal::service('comment.statistics')->read($entities, $entity_type);
        foreach ($result as $record) {
            // Skip fields that entity does not have.
            if (!$entities[$record->entity_id]
                ->hasField($record->field_name)) {
                continue;
            }
            $comment_statistics = $entities[$record->entity_id]
                ->get($record->field_name);
            $comment_statistics->cid = $record->cid;
            $comment_statistics->last_comment_timestamp = $record->last_comment_timestamp;
            $comment_statistics->last_comment_name = $record->last_comment_name;
            $comment_statistics->last_comment_uid = $record->last_comment_uid;
            $comment_statistics->comment_count = $record->comment_count;
        }
    }
    
    /**
     * Implements hook_entity_insert().
     */
    public function entityInsert(EntityInterface $entity) {
        // Allow bulk updates and inserts to temporarily disable the
        // maintenance of the {comment_entity_statistics} table.
        if (\Drupal::state()->get('comment.maintain_entity_statistics') && ($fields = \Drupal::service('comment.manager')->getFields($entity->getEntityTypeId()))) {
            \Drupal::service('comment.statistics')->create($entity, $fields);
        }
    }
    
    /**
     * Implements hook_entity_predelete().
     */
    public function entityPredelete(EntityInterface $entity) {
        // Entities can have non-numeric IDs, but {comment} and
        // {comment_entity_statistics} tables have integer columns for entity ID, and
        // PostgreSQL throws exceptions if you attempt query conditions with
        // mismatched types. So, we need to verify that the ID is numeric (even for an
        // entity type that has an integer ID, $entity->id() might be a string
        // containing a number), and then cast it to an integer when querying.
        if ($entity instanceof FieldableEntityInterface && is_numeric($entity->id())) {
            $entity_query = \Drupal::entityQuery('comment')->accessCheck(FALSE);
            $entity_query->condition('entity_id', (int) $entity->id());
            $entity_query->condition('entity_type', $entity->getEntityTypeId());
            $cids = $entity_query->execute();
            $comment_storage = \Drupal::entityTypeManager()->getStorage('comment');
            $comments = $comment_storage->loadMultiple($cids);
            $comment_storage->delete($comments);
            \Drupal::service('comment.statistics')->delete($entity);
        }
    }
    
    /**
     * Implements hook_node_update_index().
     */
    public function nodeUpdateIndex(EntityInterface $node) {
        $index_comments =& drupal_static('comment_node_update_index');
        if ($index_comments === NULL) {
            // Do not index in the following three cases:
            // 1. 'Authenticated user' can search content but can't access comments.
            // 2. 'Anonymous user' can search content but can't access comments.
            // 3. Any role can search content but can't access comments and access
            // comments is not granted by the 'authenticated user' role. In this case
            // all users might have both permissions from various roles but it is also
            // possible to set up a user to have only search content and so a user
            // edit could change the security situation so it is not safe to index the
            // comments.
            $index_comments = TRUE;
            $roles = \Drupal::entityTypeManager()->getStorage('user_role')
                ->loadMultiple();
            $authenticated_can_access = $roles[RoleInterface::AUTHENTICATED_ID]->hasPermission('access comments');
            foreach ($roles as $rid => $role) {
                if ($role->hasPermission('search content') && !$role->hasPermission('access comments')) {
                    if ($rid == RoleInterface::AUTHENTICATED_ID || $rid == RoleInterface::ANONYMOUS_ID || !$authenticated_can_access) {
                        $index_comments = FALSE;
                        break;
                    }
                }
            }
        }
        $build = [];
        if ($index_comments) {
            foreach (\Drupal::service('comment.manager')->getFields('node') as $field_name => $info) {
                // Skip fields that entity does not have.
                if (!$node->hasField($field_name)) {
                    continue;
                }
                $field_definition = $node->getFieldDefinition($field_name);
                $mode = $field_definition->getSetting('default_mode');
                $comments_per_page = $field_definition->getSetting('per_page');
                if ($node->get($field_name)->status) {
                    $comments = \Drupal::entityTypeManager()->getStorage('comment')
                        ->loadThread($node, $field_name, $mode, $comments_per_page);
                    if ($comments) {
                        $build[] = \Drupal::entityTypeManager()->getViewBuilder('comment')
                            ->viewMultiple($comments);
                    }
                }
            }
        }
        return \Drupal::service('renderer')->renderInIsolation($build);
    }
    
    /**
     * Implements hook_cron().
     */
    public function cron() {
        // Store the maximum possible comments per thread (used for node search
        // ranking by reply count).
        \Drupal::state()->set('comment.node_comment_statistics_scale', 1.0 / max(1, \Drupal::service('comment.statistics')->getMaximumCount('node')));
    }
    
    /**
     * Implements hook_node_search_result().
     *
     * Formats a comment count string and returns it, for display with search
     * results.
     */
    public function nodeSearchResult(EntityInterface $node) {
        $comment_fields = \Drupal::service('comment.manager')->getFields('node');
        $comments = 0;
        $open = FALSE;
        foreach ($comment_fields as $field_name => $info) {
            // Skip fields that entity does not have.
            if (!$node->hasField($field_name)) {
                continue;
            }
            // Do not make a string if comments are hidden.
            $status = $node->get($field_name)->status;
            if (\Drupal::currentUser()->hasPermission('access comments') && $status != CommentItemInterface::HIDDEN) {
                if ($status == CommentItemInterface::OPEN) {
                    // At least one comment field is open.
                    $open = TRUE;
                }
                $comments += $node->get($field_name)->comment_count;
            }
        }
        // Do not make a string if there are no comment fields, or no comments exist
        // or all comment fields are hidden.
        if ($comments > 0 || $open) {
            return [
                'comment' => \Drupal::translation()->formatPlural($comments, '1 comment', '@count comments'),
            ];
        }
    }
    
    /**
     * Implements hook_user_cancel().
     */
    public function userCancel($edit, UserInterface $account, $method) {
        switch ($method) {
            case 'user_cancel_block_unpublish':
                $comments = \Drupal::entityTypeManager()->getStorage('comment')
                    ->loadByProperties([
                    'uid' => $account->id(),
                ]);
                foreach ($comments as $comment) {
                    $comment->setUnpublished();
                    $comment->save();
                }
                break;
            case 'user_cancel_reassign':
                
                /** @var \Drupal\comment\CommentInterface[] $comments */
                $comments = \Drupal::entityTypeManager()->getStorage('comment')
                    ->loadByProperties([
                    'uid' => $account->id(),
                ]);
                foreach ($comments as $comment) {
                    $langcodes = array_keys($comment->getTranslationLanguages());
                    // For efficiency manually save the original comment before applying any
                    // changes.
                    $comment->original = clone $comment;
                    foreach ($langcodes as $langcode) {
                        $comment_translated = $comment->getTranslation($langcode);
                        $comment_translated->setOwnerId(0);
                        $comment_translated->setAuthorName(\Drupal::config('user.settings')->get('anonymous'));
                    }
                    $comment->save();
                }
                break;
        }
    }
    
    /**
     * Implements hook_ENTITY_TYPE_predelete() for user entities.
     */
    public function userPredelete($account) {
        $entity_query = \Drupal::entityQuery('comment')->accessCheck(FALSE);
        $entity_query->condition('uid', $account->id());
        $cids = $entity_query->execute();
        $comment_storage = \Drupal::entityTypeManager()->getStorage('comment');
        $comments = $comment_storage->loadMultiple($cids);
        $comment_storage->delete($comments);
    }
    
    /**
     * Implements hook_ranking().
     */
    public function ranking() {
        return \Drupal::service('comment.statistics')->getRankingInfo();
    }
    
    /**
     * Implements hook_ENTITY_TYPE_presave() for entity_view_display entities.
     */
    public function entityViewDisplayPresave(EntityViewDisplayInterface $display) {
        // Act only on comment view displays being disabled.
        if ($display->isNew() || $display->getTargetEntityTypeId() !== 'comment' || $display->status()) {
            return;
        }
        $storage = \Drupal::entityTypeManager()->getStorage('entity_view_display');
        if (!$storage->loadUnchanged($display->getOriginalId())
            ->status()) {
            return;
        }
        // Disable the comment field formatter when the used view display is disabled.
        foreach ($storage->loadMultiple() as $view_display) {
            $changed = FALSE;
            
            /** @var \Drupal\Core\Entity\Display\EntityViewDisplayInterface $view_display */
            foreach ($view_display->getComponents() as $field => $component) {
                if (isset($component['type']) && $component['type'] === 'comment_default') {
                    if ($component['settings']['view_mode'] === $display->getMode()) {
                        $view_display->removeComponent($field);
                        
                        /** @var \Drupal\Core\Entity\EntityViewModeInterface $mode */
                        $mode = EntityViewMode::load($display->getTargetEntityTypeId() . '.' . $display->getMode());
                        $arguments = [
                            '@id' => $view_display->id(),
                            '@name' => $field,
                            '@display' => $mode->label(),
                            '@mode' => $display->getMode(),
                        ];
                        \Drupal::logger('system')->warning("View display '@id': Comment field formatter '@name' was disabled because it is using the comment view display '@display' (@mode) that was just disabled.", $arguments);
                        $changed = TRUE;
                    }
                }
            }
            if ($changed) {
                $view_display->save();
            }
        }
    }
    
    /**
     * Implements hook_field_type_category_info_alter().
     */
    public function fieldTypeCategoryInfoAlter(&$definitions) {
        // The `comment` field type belongs in the `general` category, so the
        // libraries need to be attached using an alter hook.
        $definitions[FieldTypeCategoryManagerInterface::FALLBACK_CATEGORY]['libraries'][] = 'comment/drupal.comment-icon';
    }

}