class Node

class Node extends DrupalSqlBase {
    
    /**
     * The join options between the node and the node_revisions table.
     */
    const JOIN = 'n.vid = nr.vid';
    
    /**
     * The default filter format.
     *
     * @var string
     */
    protected $filterDefaultFormat;
    
    /**
     * Cached field and field instance definitions.
     *
     * @var array
     */
    protected $fieldInfo;
    
    /**
     * The module handler.
     *
     * @var \Drupal\Core\Extension\ModuleHandler
     */
    protected $moduleHandler;
    
    /**
     * {@inheritdoc}
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, StateInterface $state, EntityTypeManagerInterface $entity_type_manager, ModuleHandler $module_handler) {
        parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $state, $entity_type_manager);
        $this->moduleHandler = $module_handler;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration = NULL) {
        return new static($configuration, $plugin_id, $plugin_definition, $migration, $container->get('state'), $container->get('entity_type.manager'), $container->get('module_handler'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function query() {
        $query = $this->select('node_revisions', 'nr');
        $query->innerJoin('node', 'n', static::JOIN);
        $this->handleTranslations($query);
        $query->fields('n', [
            'nid',
            'type',
            'language',
            'status',
            'created',
            'changed',
            'comment',
            'promote',
            'moderate',
            'sticky',
            'tnid',
            'translate',
        ])
            ->fields('nr', [
            'title',
            'body',
            'teaser',
            'log',
            'timestamp',
            'format',
            'vid',
        ]);
        $query->addField('n', 'uid', 'node_uid');
        $query->addField('nr', 'uid', 'revision_uid');
        // If the content_translation module is enabled, get the source langcode
        // to fill the content_translation_source field.
        if ($this->moduleHandler
            ->moduleExists('content_translation')) {
            $query->leftJoin('node', 'nt', 'n.tnid = nt.nid');
            $query->addField('nt', 'language', 'source_langcode');
        }
        if (isset($this->configuration['node_type'])) {
            $query->condition('n.type', $this->configuration['node_type']);
        }
        return $query;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function initializeIterator() {
        $this->filterDefaultFormat = $this->variableGet('filter_default_format', '1');
        return parent::initializeIterator();
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() {
        $fields = [
            'nid' => $this->t('Node ID'),
            'type' => $this->t('Type'),
            'title' => $this->t('Title'),
            'body' => $this->t('Body'),
            'format' => $this->t('Format'),
            'teaser' => $this->t('Teaser'),
            'node_uid' => $this->t('Node authored by (uid)'),
            'revision_uid' => $this->t('Revision authored by (uid)'),
            'created' => $this->t('Created timestamp'),
            'changed' => $this->t('Modified timestamp'),
            'status' => $this->t('Published'),
            'promote' => $this->t('Promoted to front page'),
            'sticky' => $this->t('Sticky at top of lists'),
            'revision' => $this->t('Create new revision'),
            'language' => $this->t('Language (fr, en, ...)'),
            'tnid' => $this->t('The translation set id for this node'),
            'timestamp' => $this->t('The timestamp the latest revision of this node was created.'),
        ];
        return $fields;
    }
    
    /**
     * {@inheritdoc}
     */
    public function prepareRow(Row $row) {
        // format = 0 can happen when the body field is hidden. Set the format to 1
        // to avoid migration map issues (since the body field isn't used anyway).
        if ($row->getSourceProperty('format') === '0') {
            $row->setSourceProperty('format', $this->filterDefaultFormat);
        }
        if ($this->moduleExists('content') && $this->getModuleSchemaVersion('content') >= 6001) {
            foreach ($this->getFieldValues($row) as $field => $values) {
                $row->setSourceProperty($field, $values);
            }
        }
        // Make sure we always have a translation set.
        if ($row->getSourceProperty('tnid') == 0) {
            $row->setSourceProperty('tnid', $row->getSourceProperty('nid'));
        }
        return parent::prepareRow($row);
    }
    
    /**
     * Gets field values for a node.
     *
     * @param \Drupal\migrate\Row $node
     *   The node.
     *
     * @return array
     *   Field values, keyed by field name.
     */
    protected function getFieldValues(Row $node) {
        $values = [];
        foreach ($this->getFieldInfo($node->getSourceProperty('type')) as $field => $info) {
            $values[$field] = $this->getFieldData($info, $node);
        }
        return $values;
    }
    
    /**
     * Gets field and instance definitions from the database.
     *
     * @param string $node_type
     *   The node type for which to get field info.
     *
     * @return array
     *   Field and instance information for the node type, keyed by field name.
     */
    protected function getFieldInfo($node_type) {
        if (!isset($this->fieldInfo)) {
            $this->fieldInfo = [];
            // Query the database directly for all field info.
            $query = $this->select('content_node_field_instance', 'cnfi');
            $query->join('content_node_field', 'cnf', 'cnf.field_name = cnfi.field_name');
            $query->fields('cnfi');
            $query->fields('cnf');
            foreach ($query->execute() as $field) {
                $this->fieldInfo[$field['type_name']][$field['field_name']] = $field;
            }
            foreach ($this->fieldInfo as $type => $fields) {
                foreach ($fields as $field => $info) {
                    foreach ($info as $property => $value) {
                        if ($property == 'db_columns' || preg_match('/_settings$/', $property)) {
                            $this->fieldInfo[$type][$field][$property] = unserialize($value);
                        }
                    }
                }
            }
        }
        return isset($this->fieldInfo[$node_type]) ? $this->fieldInfo[$node_type] : [];
    }
    
    /**
     * Retrieves raw field data for a node.
     *
     * @param array $field
     *   A field and instance definition from getFieldInfo().
     * @param \Drupal\migrate\Row $node
     *   The node.
     *
     * @return array
     *   The field values, keyed by delta.
     */
    protected function getFieldData(array $field, Row $node) {
        $field_table = 'content_' . $field['field_name'];
        $node_table = 'content_type_' . $node->getSourceProperty('type');
        
        /** @var \Drupal\Core\Database\Schema $db */
        $db = $this->getDatabase()
            ->schema();
        if ($db->tableExists($field_table)) {
            $query = $this->select($field_table, 't');
            // If the delta column does not exist, add it as an expression to
            // normalize the query results.
            if ($db->fieldExists($field_table, 'delta')) {
                $query->addField('t', 'delta');
            }
            else {
                $query->addExpression(0, 'delta');
            }
        }
        elseif ($db->tableExists($node_table)) {
            $query = $this->select($node_table, 't');
            // Every row should have a delta of 0.
            $query->addExpression(0, 'delta');
        }
        if (isset($query)) {
            $columns = array_keys($field['db_columns']);
            // Add every column in the field's schema.
            foreach ($columns as $column) {
                $query->addField('t', $field['field_name'] . '_' . $column, $column);
            }
            return $query->isNotNull($field['field_name'] . '_' . $columns[0])
                ->condition('nid', $node->getSourceProperty('nid'))
                ->condition('vid', $node->getSourceProperty('vid'))
                ->execute()
                ->fetchAllAssoc('delta');
        }
        else {
            return [];
        }
    }
    
    /**
     * Retrieves raw field data for a node.
     *
     * @deprecated in drupal:8.2.0 and is removed from drupal:9.0.0. Use
     *   getFieldData() instead.
     *
     * @param array $field
     *   A field and instance definition from getFieldInfo().
     * @param \Drupal\migrate\Row $node
     *   The node.
     *
     * @return array
     *   The field values, keyed by delta.
     */
    protected function getCckData(array $field, Row $node) {
        return $this->getFieldData($field, $node);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() {
        $ids['nid']['type'] = 'integer';
        $ids['nid']['alias'] = 'n';
        return $ids;
    }
    
    /**
     * Adapt our query for translations.
     *
     * @param \Drupal\Core\Database\Query\SelectInterface $query
     *   The generated query.
     */
    protected function handleTranslations(SelectInterface $query) {
        // Check whether or not we want translations.
        if (empty($this->configuration['translations'])) {
            // No translations: Yield untranslated nodes, or default translations.
            $query->where('n.tnid = 0 OR n.tnid = n.nid');
        }
        else {
            // Translations: Yield only non-default translations.
            $query->where('n.tnid <> 0 AND n.tnid <> n.nid');
        }
    }

}