class Row

class Row {
    
    /**
     * The actual values of the source row.
     *
     * @var array
     */
    protected $source = [];
    
    /**
     * The source identifiers.
     *
     * @var array
     */
    protected $sourceIds = [];
    
    /**
     * The destination values.
     *
     * @var array
     */
    protected $destination = [];
    
    /**
     * Level separator of destination and source properties.
     */
    const PROPERTY_SEPARATOR = '/';
    
    /**
     * The mapping between source and destination identifiers.
     *
     * @var array
     */
    protected $idMap = [
        'original_hash' => '',
        'hash' => '',
        'source_row_status' => MigrateIdMapInterface::STATUS_NEEDS_UPDATE,
    ];
    
    /**
     * Whether the source has been frozen already.
     *
     * Once frozen the source can not be changed any more.
     *
     * @var bool
     */
    protected $frozen = FALSE;
    
    /**
     * The raw destination properties.
     *
     * Unlike $destination which is set by using
     * \Drupal\Component\Utility\NestedArray::setValue() this array contains
     * the destination as setDestinationProperty was called.
     *
     * @var array
     *   The raw destination.
     *
     * @see getRawDestination()
     */
    protected $rawDestination = [];
    
    /**
     * TRUE when this row is a stub.
     *
     * @var bool
     */
    protected $isStub = FALSE;
    
    /**
     * The empty destination properties.
     *
     * @var array
     */
    protected $emptyDestinationProperties = [];
    
    /**
     * Constructs a \Drupal\migrate\Row object.
     *
     * @param array $values
     *   An array of values to add as properties on the object.
     * @param array $source_ids
     *   An array containing the IDs of the source using the keys as the field
     *   names.
     * @param bool $is_stub
     *   TRUE if the row being created is a stub.
     *
     * @throws \InvalidArgumentException
     *   Thrown when a source ID property does not exist.
     */
    public function __construct(array $values = [], array $source_ids = [], $is_stub = FALSE) {
        $this->source = $values;
        $this->sourceIds = $source_ids;
        $this->isStub = $is_stub;
        foreach (array_keys($source_ids) as $id) {
            if (!$this->hasSourceProperty($id)) {
                throw new \InvalidArgumentException("'{$id}' is defined as a source ID but has no value.");
            }
        }
    }
    
    /**
     * Retrieves the values of the source identifiers.
     *
     * @return array
     *   An array containing the values of the source identifiers. Returns values
     *   in the same order as defined in $this->sourceIds.
     */
    public function getSourceIdValues() {
        return array_merge($this->sourceIds, array_intersect_key($this->source, $this->sourceIds));
    }
    
    /**
     * Determines whether a source has a property.
     *
     * @param string $property
     *   A property on the source.
     *
     * @return bool
     *   TRUE if the source has property; FALSE otherwise.
     */
    public function hasSourceProperty($property) {
        return NestedArray::keyExists($this->source, explode(static::PROPERTY_SEPARATOR, $property));
    }
    
    /**
     * Retrieves a source property.
     *
     * This function directly retrieves a source property. It does not unescape
     * '@' symbols. This is most useful in source plugins when you don't want to
     * worry about escaping '@' symbols. If using this in a process plugin to
     * retrieve a source property based on a configuration value, consider if the
     * ::get() function might be more appropriate, to allow the migration to
     * potentially specify a destination key as well.
     *
     * @param string $property
     *   A property on the source.
     *
     * @return mixed|null
     *   The found returned property or NULL if not found.
     */
    public function getSourceProperty($property) {
        $return = NestedArray::getValue($this->source, explode(static::PROPERTY_SEPARATOR, $property), $key_exists);
        if ($key_exists) {
            return $return;
        }
    }
    
    /**
     * Retrieves all source properties.
     *
     * @return array
     *   An array containing all source property values, keyed by the property
     *   name.
     */
    public function getSource() {
        return $this->source;
    }
    
    /**
     * Sets a source property if the row is not frozen.
     *
     * This can only be called from the source plugin.
     *
     * @param string $property
     *   A property on the source.
     * @param mixed $data
     *   The property value to set on the source.
     *
     * @throws \Exception
     *
     * @see \Drupal\migrate\Plugin\migrate\source\SourcePluginBase::next
     */
    public function setSourceProperty($property, $data) {
        if ($this->frozen) {
            throw new \Exception("The source is frozen and can't be changed any more");
        }
        else {
            NestedArray::setValue($this->source, explode(static::PROPERTY_SEPARATOR, $property), $data, TRUE);
        }
    }
    
    /**
     * Freezes the source.
     *
     * @return $this
     */
    public function freezeSource() {
        $this->frozen = TRUE;
        return $this;
    }
    
    /**
     * Clones the row with an empty set of destination values.
     *
     * @return static
     */
    public function cloneWithoutDestination() {
        return (new static($this->getSource(), $this->sourceIds, $this->isStub()))
            ->freezeSource();
    }
    
    /**
     * Tests if destination property exists.
     *
     * @param array|string $property
     *   An array of properties on the destination.
     *
     * @return bool
     *   TRUE if the destination property exists.
     */
    public function hasDestinationProperty($property) {
        return NestedArray::keyExists($this->destination, explode(static::PROPERTY_SEPARATOR, $property));
    }
    
    /**
     * Sets destination properties.
     *
     * @param string $property
     *   The name of the destination property.
     * @param mixed $value
     *   The property value to set on the destination.
     */
    public function setDestinationProperty($property, $value) {
        $this->rawDestination[$property] = $value;
        NestedArray::setValue($this->destination, explode(static::PROPERTY_SEPARATOR, $property), $value, TRUE);
    }
    
    /**
     * Removes destination property.
     *
     * @param string $property
     *   The name of the destination property.
     */
    public function removeDestinationProperty($property) {
        unset($this->rawDestination[$property]);
        NestedArray::unsetValue($this->destination, explode(static::PROPERTY_SEPARATOR, $property));
    }
    
    /**
     * Sets a destination to be empty.
     *
     * @param string $property
     *   The destination property.
     */
    public function setEmptyDestinationProperty($property) {
        $this->emptyDestinationProperties[] = $property;
    }
    
    /**
     * Gets the empty destination properties.
     *
     * @return array
     *   An array of destination properties.
     */
    public function getEmptyDestinationProperties() {
        return $this->emptyDestinationProperties;
    }
    
    /**
     * Returns the whole destination array.
     *
     * @return array
     *   An array of destination values.
     */
    public function getDestination() {
        return $this->destination;
    }
    
    /**
     * Returns the raw destination. Rarely necessary.
     *
     * For example calling setDestination('foo/bar', 'baz') results in
     * @code
     * $this->destination['foo']['bar'] = 'baz';
     * $this->rawDestination['foo/bar'] = 'baz';
     * @endcode
     *
     * @return array
     *   The raw destination values.
     */
    public function getRawDestination() {
        return $this->rawDestination;
    }
    
    /**
     * Returns the value of a destination property.
     *
     * This function directly returns a destination property. The property name
     * should not begin with an @ symbol. This is most useful in a destination
     * plugin.
     *
     * @param string $property
     *   The name of a property on the destination.
     *
     * @return mixed
     *   The destination value.
     */
    public function getDestinationProperty($property) {
        return NestedArray::getValue($this->destination, explode(static::PROPERTY_SEPARATOR, $property));
    }
    
    /**
     * Retrieve a source or destination property.
     *
     * If the property key begins with '@' return a destination property,
     * otherwise return a source property. the '@' symbol itself can be escaped
     * as '@@'. Returns NULL if property is not found. Useful in process plugins
     * to retrieve a row property specified in a configuration key which may be
     * either a source or destination property prefixed with an '@'.
     *
     * @param string $property
     *   The property to get.
     *
     * @return mixed|null
     *   The requested property.
     */
    public function get($property) {
        $values = $this->getMultiple([
            $property,
        ]);
        return reset($values);
    }
    
    /**
     * Retrieve multiple source and destination properties at once.
     *
     * @param string[] $properties
     *   An array of values to retrieve, with destination values prefixed with @.
     *
     * @return array
     *   An array of property values, keyed by property name.
     */
    public function getMultiple(array $properties) {
        $return = [];
        foreach ($properties as $orig_property) {
            $property = $orig_property;
            $is_source = TRUE;
            if ($property[0] == '@') {
                $property = preg_replace_callback('/^(@?)((?:@@)*)([^@]|$)/', function ($matches) use (&$is_source) {
                    // If there are an odd number of @ in the beginning, it's a
                    // destination.
                    $is_source = empty($matches[1]);
                    // Remove the possible escaping and do not lose the terminating
                    // non-@ either.
                    return str_replace('@@', '@', $matches[2]) . $matches[3];
                }, $property);
            }
            if ($is_source) {
                $return[$orig_property] = $this->getSourceProperty($property);
            }
            else {
                $return[$orig_property] = $this->getDestinationProperty($property);
            }
        }
        return $return;
    }
    
    /**
     * Sets the Migrate ID mappings.
     *
     * @param array $id_map
     *   An array of mappings between source ID and destination ID.
     */
    public function setIdMap(array $id_map) {
        $this->idMap = $id_map;
    }
    
    /**
     * Retrieves the Migrate ID mappings.
     *
     * @return array
     *   An array of mapping between source and destination identifiers.
     */
    public function getIdMap() {
        return $this->idMap;
    }
    
    /**
     * Recalculates the hash for the row.
     */
    public function rehash() {
        $this->idMap['original_hash'] = $this->idMap['hash'];
        $this->idMap['hash'] = hash('sha256', serialize($this->source));
    }
    
    /**
     * Checks whether the row has changed compared to the original ID map.
     *
     * @return bool
     *   TRUE if the row has changed, FALSE otherwise. If setIdMap() was not
     *   called, this always returns FALSE.
     */
    public function changed() {
        return $this->idMap['original_hash'] != $this->idMap['hash'];
    }
    
    /**
     * Returns if this row needs an update.
     *
     * @return bool
     *   TRUE if the row needs updating, FALSE otherwise.
     */
    public function needsUpdate() {
        return $this->idMap['source_row_status'] == MigrateIdMapInterface::STATUS_NEEDS_UPDATE;
    }
    
    /**
     * Returns the hash for the source values..
     *
     * @return mixed
     *   The hash of the source values.
     */
    public function getHash() {
        return $this->idMap['hash'];
    }
    
    /**
     * Reports whether this row is a stub.
     *
     * @return bool
     *   The current stub value.
     */
    public function isStub() {
        return $this->isStub;
    }

}