Issue #3282696 by sanduhrs: Port of l10n_community: Add statistics service

/**

 * Service description.

 *

 * @todo

 * @todo Fix mysql performance problems.

 * These queries are *slooow*. The query cache helps a lot with caching the

 * result, so the slowness only shows for the first run, but still it would be

 * good to look into optimizing these.

  /**

   * Get summaries based on language codes.

   *

   * @param L10nServerProjectInterface|null $project

   * @param \Drupal\l10n_server\Entity\L10nServerProjectInterface $project

   *   A l10n_server_project entity.

   *

   * @return array

   *   An array containing translation and suggestion counts.

   */

  public function getLanguagesStringCount(L10nServerProjectInterface $project = NULL): array {

    $sums = [];

      // More complex joins if we also need to factor the project in.

      $count1_sql = "SELECT COUNT(DISTINCT ts.sid) AS translation_count, ts.language FROM {l10n_server_line} l INNER JOIN {l10n_server_status_flag} ts ON l.sid = ts.sid WHERE l.pid = :pid AND ts.has_translation = 1 GROUP BY ts.language";

      $count2_sql = "SELECT COUNT(DISTINCT ts.sid) AS translation_count, ts.language FROM {l10n_server_line} l INNER JOIN {l10n_server_status_flag} ts ON l.sid = ts.sid WHERE l.pid = :pid AND ts.has_suggestion = 1 GROUP BY ts.language";

      $count_args = array(':pid' => $project->id());

      $count_args = [':pid' => $project->id()];

    }

    $result = $this->connection->query($count1_sql, $count_args);

    foreach ($result as $row) {

    // Get the count of distinct strings having translations and suggestions per

    // project. This is run per project because big installs of the module were

    // choking on GROUP BY based solutions.

    // phpcs:ignore

    foreach (['translations' => 'has_translation', 'suggestions' => 'has_suggestion'] as $key => $column) {

      foreach ($sums as $pid => &$data) {

        $count_args = [];