class CommentStatistics

class CommentStatistics implements CommentStatisticsInterface {
  
  /**
   * The current database connection.
   *
   * @var \Drupal\Core\Database\Connection
   */
  protected $database;
  
  /**
   * The replica database connection.
   *
   * @var \Drupal\Core\Database\Connection
   */
  protected $databaseReplica;
  
  /**
   * The current logged in user.
   *
   * @var \Drupal\Core\Session\AccountInterface
   */
  protected $currentUser;
  
  /**
   * The entity type manager.
   *
   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
   */
  protected $entityTypeManager;
  
  /**
   * The state service.
   *
   * @var \Drupal\Core\State\StateInterface
   */
  protected $state;
  
  /**
   * Constructs the CommentStatistics service.
   *
   * @param \Drupal\Core\Database\Connection $database
   *   The active database connection.
   * @param \Drupal\Core\Session\AccountInterface $current_user
   *   The current logged in user.
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   *   The entity type manager.
   * @param \Drupal\Core\State\StateInterface $state
   *   The state service.
   * @param \Drupal\Component\Datetime\TimeInterface|null|\Drupal\Core\Database\Connection $time
   *   The time service.
   * @param \Drupal\Core\Database\Connection|null $database_replica
   *   (Optional) the replica database connection.
   */
  public function __construct(Connection $database, AccountInterface $current_user, EntityTypeManagerInterface $entity_type_manager, StateInterface $state, protected TimeInterface|Connection|null $time = NULL, ?Connection $database_replica = NULL) {
    $this->database = $database;
    $this->currentUser = $current_user;
    $this->entityTypeManager = $entity_type_manager;
    $this->state = $state;
    if (!$time || $time instanceof Connection) {
      @trigger_error('Calling ' . __METHOD__ . '() without the $time argument is deprecated in drupal:10.3.0 and it will be the 4th argument in drupal:11.0.0. See https://www.drupal.org/node/3387233', E_USER_DEPRECATED);
      if ($time instanceof Connection) {
        $database_replica = $time;
      }
      $this->time = \Drupal::service(TimeInterface::class);
    }
    $this->databaseReplica = $database_replica ?: $database;
  }
  
  /**
   * {@inheritdoc}
   */
  public function read($entities, $entity_type, $accurate = TRUE) {
    $connection = $accurate ? $this->database : $this->databaseReplica;
    $stats = $connection->select('comment_entity_statistics', 'ces')
      ->fields('ces')
      ->condition('ces.entity_id', array_keys($entities), 'IN')
      ->condition('ces.entity_type', $entity_type)
      ->execute();
    $statistics_records = [];
    while ($entry = $stats->fetchObject()) {
      $statistics_records[] = $entry;
    }
    return $statistics_records;
  }
  
  /**
   * {@inheritdoc}
   */
  public function delete(EntityInterface $entity) {
    $this->database
      ->delete('comment_entity_statistics')
      ->condition('entity_id', $entity->id())
      ->condition('entity_type', $entity->getEntityTypeId())
      ->execute();
  }
  
  /**
   * {@inheritdoc}
   */
  public function create(FieldableEntityInterface $entity, $fields) {
    $query = $this->database
      ->insert('comment_entity_statistics')
      ->fields([
      'entity_id',
      'entity_type',
      'field_name',
      'cid',
      'last_comment_timestamp',
      'last_comment_name',
      'last_comment_uid',
      'comment_count',
    ]);
    foreach ($fields as $field_name => $detail) {
      // Skip fields that entity does not have.
      if (!$entity->hasField($field_name)) {
        continue;
      }
      // Get the user ID from the entity if it's set, or default to the
      // currently logged in user.
      $last_comment_uid = 0;
      if ($entity instanceof EntityOwnerInterface) {
        $last_comment_uid = $entity->getOwnerId();
      }
      if (!isset($last_comment_uid)) {
        // Default to current user when entity does not implement
        // EntityOwnerInterface or author is not set.
        $last_comment_uid = $this->currentUser
          ->id();
      }
      // Default to request time when entity does not have a changed property.
      $last_comment_timestamp = $this->time
        ->getRequestTime();
      // @todo Make comment statistics language aware and add some tests. See
      //   https://www.drupal.org/node/2318875
      if ($entity instanceof EntityChangedInterface) {
        $last_comment_timestamp = $entity->getChangedTimeAcrossTranslations();
      }
      $query->values([
        'entity_id' => $entity->id(),
        'entity_type' => $entity->getEntityTypeId(),
        'field_name' => $field_name,
        'cid' => 0,
        'last_comment_timestamp' => $last_comment_timestamp,
        'last_comment_name' => NULL,
        'last_comment_uid' => $last_comment_uid,
        'comment_count' => 0,
      ]);
    }
    $query->execute();
  }
  
  /**
   * {@inheritdoc}
   */
  public function getMaximumCount($entity_type) {
    return $this->database
      ->query('SELECT MAX([comment_count]) FROM {comment_entity_statistics} WHERE [entity_type] = :entity_type', [
      ':entity_type' => $entity_type,
    ])
      ->fetchField();
  }
  
  /**
   * {@inheritdoc}
   */
  public function getRankingInfo() {
    return [
      'comments' => [
        'title' => t('Number of comments'),
        'join' => [
          'type' => 'LEFT',
          'table' => 'comment_entity_statistics',
          'alias' => 'ces',
          // Default to comment field as this is the most common use case for
          // nodes.
'on' => "ces.entity_id = i.sid AND ces.entity_type = 'node' AND ces.field_name = 'comment'",
        ],
        // Inverse law that maps the highest view count on the site to 1 and 0
        // to 0. Note that the ROUND here is necessary for PostgreSQL and SQLite
        // in order to ensure that the :comment_scale argument is treated as
        // a numeric type, because the PostgreSQL PDO driver sometimes puts
        // values in as strings instead of numbers in complex expressions like
        // this.
'score' => '2.0 - 2.0 / (1.0 + ces.comment_count * (ROUND(:comment_scale, 4)))',
        'arguments' => [
          ':comment_scale' => \Drupal::state()->get('comment.node_comment_statistics_scale', 0),
        ],
      ],
    ];
  }
  
  /**
   * {@inheritdoc}
   */
  public function update(CommentInterface $comment) {
    // Allow bulk updates and inserts to temporarily disable the maintenance of
    // the {comment_entity_statistics} table.
    if (!$this->state
      ->get('comment.maintain_entity_statistics')) {
      return;
    }
    $query = $this->database
      ->select('comment_field_data', 'c');
    $query->addExpression('COUNT([cid])');
    $count = $query->condition('c.entity_id', $comment->getCommentedEntityId())
      ->condition('c.entity_type', $comment->getCommentedEntityTypeId())
      ->condition('c.field_name', $comment->getFieldName())
      ->condition('c.status', CommentInterface::PUBLISHED)
      ->condition('default_langcode', 1)
      ->execute()
      ->fetchField();
    if ($count > 0) {
      // Comments exist.
      $last_reply = $this->database
        ->select('comment_field_data', 'c')
        ->fields('c', [
        'cid',
        'name',
        'changed',
        'uid',
      ])
        ->condition('c.entity_id', $comment->getCommentedEntityId())
        ->condition('c.entity_type', $comment->getCommentedEntityTypeId())
        ->condition('c.field_name', $comment->getFieldName())
        ->condition('c.status', CommentInterface::PUBLISHED)
        ->condition('default_langcode', 1)
        ->orderBy('c.created', 'DESC')
        ->range(0, 1)
        ->execute()
        ->fetchObject();
      // Use merge here because entity could be created before comment field.
      $this->database
        ->merge('comment_entity_statistics')
        ->fields([
        'cid' => $last_reply->cid,
        'comment_count' => $count,
        'last_comment_timestamp' => $last_reply->changed,
        'last_comment_name' => $last_reply->uid ? '' : $last_reply->name,
        'last_comment_uid' => $last_reply->uid,
      ])
        ->keys([
        'entity_id' => $comment->getCommentedEntityId(),
        'entity_type' => $comment->getCommentedEntityTypeId(),
        'field_name' => $comment->getFieldName(),
      ])
        ->execute();
    }
    else {
      // Comments do not exist.
      $entity = $comment->getCommentedEntity();
      // Get the user ID from the entity if it's set, or default to the
      // currently logged in user.
      if ($entity instanceof EntityOwnerInterface) {
        $last_comment_uid = $entity->getOwnerId();
      }
      if (!isset($last_comment_uid)) {
        // Default to current user when entity does not implement
        // EntityOwnerInterface or author is not set.
        $last_comment_uid = $this->currentUser
          ->id();
      }
      $this->database
        ->update('comment_entity_statistics')
        ->fields([
        'cid' => 0,
        'comment_count' => 0,
        // Use the changed date of the entity if it's set, or default to
        // request time.
'last_comment_timestamp' => $entity instanceof EntityChangedInterface ? $entity->getChangedTimeAcrossTranslations() : $this->time
          ->getRequestTime(),
        'last_comment_name' => '',
        'last_comment_uid' => $last_comment_uid,
      ])
        ->condition('entity_id', $comment->getCommentedEntityId())
        ->condition('entity_type', $comment->getCommentedEntityTypeId())
        ->condition('field_name', $comment->getFieldName())
        ->execute();
    }
    // Reset the cache of the commented entity so that when the entity is loaded
    // the next time, the statistics will be loaded again.
    $this->entityTypeManager
      ->getStorage($comment->getCommentedEntityTypeId())
      ->resetCache([
      $comment->getCommentedEntityId(),
    ]);
  }

}