<?php

namespace Drupal\migrate;

use Drupal\Component\Utility\NestedArray;
use Drupal\migrate\Plugin\MigrateIdMapInterface;

/**
 * Stores a 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;
  }

}
