class VariableTranslation

class VariableTranslation extends DrupalSqlBase {
    
    /**
     * The variable names to fetch.
     *
     * @var array
     */
    protected $variables;
    
    /**
     * {@inheritdoc}
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, StateInterface $state, EntityTypeManagerInterface $entity_type_manager) {
        parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $state, $entity_type_manager);
        $this->variables = $this->configuration['variables'];
    }
    
    /**
     * {@inheritdoc}
     */
    protected function initializeIterator() {
        return new \ArrayIterator($this->values());
    }
    
    /**
     * Return the values of the variables specified in the plugin configuration.
     *
     * @return array
     *   An associative array where the keys are the variables specified in the
     *   plugin configuration and the values are the values found in the source.
     *   A key/value pair is added for the language code. Only those values are
     *   returned that are actually in the database.
     */
    protected function values() {
        $values = [];
        $result = $this->prepareQuery()
            ->execute()
            ->FetchAllAssoc('language');
        foreach ($result as $i18n_variable) {
            $values[]['language'] = $i18n_variable->language;
        }
        $result = $this->prepareQuery()
            ->execute()
            ->FetchAll();
        foreach ($result as $i18n_variable) {
            foreach ($values as $key => $value) {
                if ($values[$key]['language'] === $i18n_variable->language) {
                    $values[$key][$i18n_variable->name] = unserialize($i18n_variable->value);
                    break;
                }
            }
        }
        return $values;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function doCount() {
        return $this->initializeIterator()
            ->count();
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        return array_combine($this->variables, $this->variables);
    }
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        return $this->getDatabase()
            ->select('i18n_variable', 'v')
            ->fields('v')
            ->condition('name', (array) $this->configuration['variables'], 'IN');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['language']['type'] = 'string';
        return $ids;
    }
    
    /**
     * {@inheritdoc}
     */
    public function checkRequirements() {
        if (!$this->getDatabase()
            ->schema()
            ->tableExists('i18n_variable')) {
            throw new RequirementsException("Source database table 'i18n_variable' does not exist");
        }
        parent::checkRequirements();
    }

}