class BlockTranslation

class BlockTranslation extends Block {
  
  /**
   * {@inheritdoc}
   */
  public function query() {
    // Let the parent set the block table to use, but do not use the parent
    // query. Instead build a query so can use an inner join to the selected
    // block table.
    parent::query();
    $query = $this->select('i18n_string', 'i18n')
      ->fields('i18n')
      ->fields('b', [
      'bid',
      'module',
      'delta',
      'theme',
      'status',
      'weight',
      'region',
      'custom',
      'visibility',
      'pages',
      'title',
      'cache',
      'i18n_mode',
    ])
      ->fields('lt', [
      'lid',
      'translation',
      'language',
      'plid',
      'plural',
    ])
      ->condition('i18n_mode', 1);
    $query->leftJoin($this->blockTable, 'b', '[b].[delta] = [i18n].[objectid]');
    $query->innerJoin('locales_target', 'lt', '[lt].[lid] = [i18n].[lid]');
    // The i18n_string module adds a status column to locale_target. It was
    // originally 'status' in a later revision it was named 'i18n_status'.
    if ($this->getDatabase()
      ->schema()
      ->fieldExists('locales_target', 'status')) {
      $query->addField('lt', 'status', 'i18n_status');
    }
    if ($this->getDatabase()
      ->schema()
      ->fieldExists('locales_target', 'i18n_status')) {
      $query->addField('lt', 'i18n_status', 'i18n_status');
    }
    return $query;
  }
  
  /**
   * {@inheritdoc}
   */
  public function fields() {
    return [
      'bid' => $this->t('The block numeric identifier.'),
      'module' => $this->t('The module providing the block.'),
      'delta' => $this->t("The block's delta."),
      'theme' => $this->t('Which theme the block is placed in.'),
      'status' => $this->t('Block enabled status'),
      'weight' => $this->t('Block weight within region'),
      'region' => $this->t('Theme region within which the block is set'),
      'visibility' => $this->t('Visibility'),
      'pages' => $this->t('Pages list.'),
      'title' => $this->t('Block title.'),
      'cache' => $this->t('Cache rule.'),
      'i18n_mode' => $this->t('Multilingual mode'),
      'lid' => $this->t('Language string ID'),
      'textgroup' => $this->t('A module defined group of translations'),
      'context' => $this->t('Full string ID for quick search: type:objectid:property.'),
      'objectid' => $this->t('Object ID'),
      'type' => $this->t('Object type for this string'),
      'property' => $this->t('Object property for this string'),
      'objectindex' => $this->t('Integer value of Object ID'),
      'format' => $this->t('The {filter_format}.format of the string'),
      'translation' => $this->t('Translation'),
      'language' => $this->t('Language code'),
      'plid' => $this->t('Parent lid'),
      'plural' => $this->t('Plural index number'),
      'i18n_status' => $this->t('Translation needs update'),
    ];
  }
  
  /**
   * {@inheritdoc}
   */
  public function getIds() {
    $ids['delta']['type'] = 'string';
    $ids['delta']['alias'] = 'b';
    $ids['language']['type'] = 'string';
    return $ids;
  }

}