interface MigrateIdMapInterface

interface MigrateIdMapInterface extends \Iterator, PluginInspectionInterface {
    
    /**
     * Indicates that the import of the row was successful.
     */
    const STATUS_IMPORTED = 0;
    
    /**
     * Indicates that the row needs to be updated.
     */
    const STATUS_NEEDS_UPDATE = 1;
    
    /**
     * Indicates that the import of the row was ignored.
     */
    const STATUS_IGNORED = 2;
    
    /**
     * Indicates that the import of the row failed.
     */
    const STATUS_FAILED = 3;
    
    /**
     * Indicates that the data for the row is to be deleted.
     */
    const ROLLBACK_DELETE = 0;
    
    /**
     * Indicates that the data for the row is to be preserved.
     *
     * Rows that refer to entities that already exist on the destination and are
     * being updated are preserved.
     */
    const ROLLBACK_PRESERVE = 1;
    
    /**
     * Saves a mapping from the source identifiers to the destination identifiers.
     *
     * Called upon import of one row, we record a mapping from the source ID to
     * the destination ID. Also may be called, setting the third parameter to
     * NEEDS_UPDATE, to signal an existing record should be re-migrated.
     *
     * @param \Drupal\migrate\Row $row
     *   The raw source data. We use the ID map derived from the source object
     *   to get the source identifier values.
     * @param array $destination_id_values
     *   An array of destination identifier values.
     * @param int $status
     *   (optional) Status of the source row in the map. Defaults to
     *   self::STATUS_IMPORTED.
     * @param int $rollback_action
     *   (optional) How to handle the destination object on rollback. Defaults to
     *   self::ROLLBACK_DELETE.
     */
    public function saveIdMapping(Row $row, array $destination_id_values, $status = self::STATUS_IMPORTED, $rollback_action = self::ROLLBACK_DELETE);
    
    /**
     * Saves a message related to a source record in the migration message table.
     *
     * @param array $source_id_values
     *   The source identifier keyed values of the record, e.g. ['nid' => 5].
     * @param string $message
     *   The message to record.
     * @param int $level
     *   (optional) The message severity. Defaults to
     *   MigrationInterface::MESSAGE_ERROR.
     */
    public function saveMessage(array $source_id_values, $message, $level = MigrationInterface::MESSAGE_ERROR);
    
    /**
     * Retrieves a traversable object of messages related to source records.
     *
     * @param array $source_id_values
     *   (optional) The source identifier keyed values of the record, e.g.
     *   ['nid' => 5]. If empty (the default), all messages are retrieved.
     * @param int $level
     *   (optional) Message severity. If NULL (the default), retrieve messages of
     *   all severities.
     *
     * @return \Traversable
     *   Retrieves a traversable object of message objects of unspecified class.
     *   Each object has the following public properties:
     *   - source_row_hash: the hash of the entire serialized source row data.
     *   - message: the text of the message.
     *   - level: one of MigrationInterface::MESSAGE_ERROR,
     *   MigrationInterface::MESSAGE_WARNING, MigrationInterface::MESSAGE_NOTICE,
     *   MigrationInterface::MESSAGE_INFORMATIONAL.
     */
    public function getMessages(array $source_id_values = [], $level = NULL);
    
    /**
     * Prepares to run a full update.
     *
     * Prepares this migration to run as an update - that is, in addition to
     * un-migrated content (source records not in the map table) being imported,
     * previously-migrated content will also be updated in place by marking all
     * previously-imported content as ready to be re-imported.
     */
    public function prepareUpdate();
    
    /**
     * Returns the number of processed items in the map.
     *
     * @return int
     *   The count of records in the map table.
     */
    public function processedCount();
    
    /**
     * Returns the number of imported items in the map.
     *
     * @return int
     *   The number of imported items.
     */
    public function importedCount();
    
    /**
     * Returns a count of items which are marked as needing update.
     *
     * @return int
     *   The number of items which need updating.
     */
    public function updateCount();
    
    /**
     * Returns the number of items that failed to import.
     *
     * @return int
     *   The number of items that failed to import.
     */
    public function errorCount();
    
    /**
     * Returns the number of messages saved.
     *
     * @return int
     *   The number of messages.
     */
    public function messageCount();
    
    /**
     * Deletes the map and message entries for a given source record.
     *
     * @param array $source_id_values
     *   The source identifier keyed values of the record, e.g. ['nid' => 5].
     * @param bool $messages_only
     *   (optional) TRUE to only delete the migrate messages. Defaults to FALSE.
     */
    public function delete(array $source_id_values, $messages_only = FALSE);
    
    /**
     * Deletes the map and message table entries for a given destination row.
     *
     * @param array $destination_id_values
     *   The destination identifier key value pairs we should do the deletes for.
     */
    public function deleteDestination(array $destination_id_values);
    
    /**
     * Clears all messages from the map.
     */
    public function clearMessages();
    
    /**
     * Retrieves a row from the map table based on source identifier values.
     *
     * @param array $source_id_values
     *   The source identifier keyed values of the record, e.g. ['nid' => 5].
     *
     * @return array
     *   The raw row data as an associative array.
     */
    public function getRowBySource(array $source_id_values);
    
    /**
     * Retrieves a row by the destination identifiers.
     *
     * @param array $destination_id_values
     *   The destination identifier keyed values of the record, e.g. ['nid' => 5].
     *
     * @return array
     *   The row(s) of data or an empty array when there is no matching map row.
     */
    public function getRowByDestination(array $destination_id_values);
    
    /**
     * Retrieves an array of map rows marked as needing update.
     *
     * @param int $count
     *   The maximum number of rows to return.
     *
     * @return array
     *   Array of map row objects that need updating.
     */
    public function getRowsNeedingUpdate($count);
    
    /**
     * Looks up the source identifier.
     *
     * Given a (possibly multi-field) destination identifier value, return the
     * (possibly multi-field) source identifier value mapped to it.
     *
     * @param array $destination_id_values
     *   The destination identifier keyed values of the record, e.g. ['nid' => 5].
     *
     * @return array
     *   The source identifier keyed values of the record, e.g. ['nid' => 5], or
     *   an empty array on failure.
     */
    public function lookupSourceId(array $destination_id_values);
    
    /**
     * Looks up the destination identifiers corresponding to a source key.
     *
     * This can look up a subset of source keys if only some are provided, and
     * will return all destination keys that match.
     *
     * @param array $source_id_values
     *   The source identifier keyed values of the records, e.g. ['nid' => 5].
     *   If un-keyed, the first count($source_id_values) keys will be assumed.
     *
     * @return array
     *   An array of arrays of destination identifier values.
     *
     * @throws \Drupal\migrate\MigrateException
     *   Thrown when $source_id_values contains unknown keys, or is the wrong
     *   length.
     */
    public function lookupDestinationIds(array $source_id_values);
    
    /**
     * Looks up the destination identifier currently being iterated.
     *
     * @return array
     *   The destination identifier values of the record, or NULL on failure.
     */
    public function currentDestination();
    
    /**
     * Looks up the source identifier(s) currently being iterated.
     *
     * @return array
     *   The source identifier values of the record, or NULL on failure.
     */
    public function currentSource();
    
    /**
     * Removes any persistent storage used by this map.
     *
     * For example, remove the map and message tables.
     */
    public function destroy();
    
    /**
     * Gets the qualified map table.
     *
     * @todo Remove this as this is SQL only and so doesn't belong to the interface.
     */
    public function getQualifiedMapTableName();
    
    /**
     * Sets the migrate message service.
     *
     * @param \Drupal\migrate\MigrateMessageInterface $message
     *   The migrate message service.
     */
    public function setMessage(MigrateMessageInterface $message);
    
    /**
     * Sets a specified record to be updated, if it exists.
     *
     * @param array $source_id_values
     *   The source identifier values of the record.
     */
    public function setUpdate(array $source_id_values);

}