<?php

namespace Drupal\feeds\Plugin\Type\Target;

use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\TranslatableInterface;
use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Language\LanguageInterface;
use Drupal\Core\Language\LanguageManagerInterface;
use Drupal\feeds\Exception\EmptyFeedException;
use Drupal\feeds\Exception\TargetValidationException;
use Drupal\feeds\FeedInterface;
use Drupal\feeds\FeedTypeInterface;
use Drupal\feeds\FieldTargetDefinition;
use Drupal\feeds\Plugin\Type\Processor\EntityProcessorInterface;

/**
 * Helper class for field mappers.
 */
abstract class FieldTargetBase extends TargetBase implements ConfigurableTargetInterface, TranslatableTargetInterface {

  /**
   * The field settings.
   *
   * @var array
   */
  protected $settings;

  /**
   * The language manager.
   *
   * @var \Drupal\Core\Language\LanguageManagerInterface
   */
  protected $languageManager;

  /**
   * {@inheritdoc}
   */
  public static function targets(array &$targets, FeedTypeInterface $feed_type, array $definition) {
    $processor = $feed_type->getProcessor();

    if (!$processor instanceof EntityProcessorInterface) {
      return $targets;
    }

    $field_definitions = \Drupal::service('entity_field.manager')->getFieldDefinitions($processor->entityType(), $processor->bundle());

    foreach ($field_definitions as $id => $field_definition) {
      if (isset($targets[$id])) {
        continue;
      }
      if ($id === $processor->bundleKey()) {
        continue;
      }
      if (in_array($field_definition->getType(), $definition['field_types'])) {
        if ($target = static::prepareTarget($field_definition)) {
          $target->setPluginId($definition['id']);
          $targets[$id] = $target;
        }
      }
    }
  }

  /**
   * Prepares a target definition.
   *
   * @param \Drupal\Core\Field\FieldDefinitionInterface $field_definition
   *   The field definition.
   *
   * @return \Drupal\feeds\FieldTargetDefinition
   *   The target definition.
   */
  protected static function prepareTarget(FieldDefinitionInterface $field_definition) {
    return FieldTargetDefinition::createFromFieldDefinition($field_definition)
      ->addProperty('value');
  }

  /**
   * {@inheritdoc}
   */
  public function __construct(array $configuration, $plugin_id, array $plugin_definition) {
    $this->targetDefinition = $configuration['target_definition'];
    $this->settings = $this->targetDefinition->getFieldDefinition()->getSettings();
    parent::__construct($configuration, $plugin_id, $plugin_definition);
  }

  /**
   * {@inheritdoc}
   */
  public function setTarget(FeedInterface $feed, EntityInterface $entity, $field_name, array $values) {
    if ($values = $this->prepareValues($values)) {
      $entity_target = $this->getEntityTarget($feed, $entity);
      if (!empty($entity_target)) {
        $item_list = $entity_target->get($field_name);

        // Append these values to the existing values.
        $values = array_merge($item_list->getValue(), $values);

        $item_list->setValue($values);
      }
    }
  }

  /**
   * {@inheritdoc}
   */
  public function isMutable() {
    return !$this->targetDefinition->getFieldDefinition()->isReadOnly();
  }

  /**
   * {@inheritdoc}
   */
  public function isEmpty(FeedInterface $feed, EntityInterface $entity, $field_name) {
    return $entity->get($field_name)->isEmpty();
  }

  /**
   * Get entity, or entity translation to set the map.
   *
   * @param \Drupal\feeds\FeedInterface $feed
   *   The feed.
   * @param \Drupal\Core\Entity\EntityInterface $entity
   *   The entity to import.
   *
   * @see \Drupal\feeds\Plugin\Type\Target\FieldTargetBase::isTargetTranslatable()
   *
   * @return \Drupal\Core\Entity\EntityInterface|null
   *   Self entity or entity translation.
   */
  public function getEntityTarget(FeedInterface $feed, EntityInterface $entity) {
    if ($entity instanceof TranslatableInterface && $this->isTargetTranslatable()) {
      if ($this->languageExists()) {
        $processor = $feed->getType()->getProcessor();
        if ($processor instanceof EntityProcessorInterface) {
          return $processor->getEntityTranslation($feed, $entity, $this->getLangcode());
        }
      }
      return;
    }

    return $entity;
  }

  /**
   * Prepares the values that will be mapped to an entity.
   *
   * @param array $values
   *   The values.
   */
  protected function prepareValues(array $values) {
    $return = [];
    foreach ($values as $delta => $columns) {
      try {
        $this->prepareValue($delta, $columns);
        $return[] = $columns;
      }
      catch (EmptyFeedException $e) {
        // Nothing wrong here.
      }
      catch (TargetValidationException $e) {
        // Validation failed.
        $this->addMessage($e->getFormattedMessage(), 'error');
      }
    }

    return $return;
  }

  /**
   * Prepares a single value.
   *
   * @param int $delta
   *   The field delta.
   * @param array $values
   *   The values.
   */
  protected function prepareValue($delta, array &$values) {
    foreach ($values as $column => $value) {
      $values[$column] = (string) $value;
    }
  }

  /**
   * Constructs a base query which is used to find an existing entity.
   *
   * @return \Drupal\Core\Entity\Query\QueryInterface
   *   An entity query.
   *
   * @see ::getUniqueValue()
   */
  protected function getUniqueQuery() {
    return \Drupal::entityQuery($this->feedType->getProcessor()->entityType())
      ->range(0, 1)->accessCheck(FALSE);
  }

  /**
   * Looks for an existing entity and returns an entity ID if found.
   *
   * @param \Drupal\feeds\FeedInterface $feed
   *   The feed that is being processed.
   * @param string $target
   *   The ID of the field target plugin.
   * @param string $key
   *   The property of the field to search on.
   * @param string $value
   *   The value to look for.
   *
   * @return string|int|null
   *   An entity ID, if found. Null otherwise.
   */
  public function getUniqueValue(FeedInterface $feed, $target, $key, $value) {
    // Make sure the passed value is a string.
    $value = $this->convertValueToString($value);

    $base_fields = \Drupal::service('entity_field.manager')->getBaseFieldDefinitions($this->feedType->getProcessor()->entityType());

    if (isset($base_fields[$target])) {
      $field = $target;
    }
    else {
      $field = "$target.$key";
    }

    // Construct "Unique" query.
    $query = $this->getUniqueQuery()
      ->condition($field, $value);

    // Restrict search to the same bundle if the entity type we import for
    // supports bundles.
    $bundle_key = $this->feedType->getProcessor()->bundleKey();
    if ($bundle_key) {
      $query->condition($bundle_key, $this->feedType->getProcessor()->bundle());
    }

    // Execute "Unique" query.
    if ($result = $query->execute()) {
      return reset($result);
    }
  }

  /**
   * Converts a value to a string, if possible.
   *
   * @param mixed $value
   *   The value to convert.
   *
   * @return string
   *   The converted value.
   *
   * @throws \Drupal\feeds\Exception\TargetValidationException
   *   In case the passed value could not be converted.
   */
  protected function convertValueToString($value): string {
    if (is_string($value)) {
      // The value is already a string.
      return $value;
    }
    if (is_scalar($value)) {
      // Cast to a string.
      return (string) $value;
    }
    if (is_null($value)) {
      return '';
    }
    if (is_array($value)) {
      return $this->convertValueToString(reset($value));
    }
    if (is_object($value) && method_exists($value, '__toString')) {
      return (string) $value;
    }
    throw new TargetValidationException('The source value for the unique target could not be converted to a string.');
  }

  /**
   * {@inheritdoc}
   */
  public function calculateDependencies() {
    $this->dependencies = parent::calculateDependencies();

    // Add the configured field as a dependency.
    $field_definition = $this->targetDefinition
      ->getFieldDefinition();
    if ($field_definition && $field_definition instanceof EntityInterface) {
      $this->dependencies['config'][] = $field_definition->getConfigDependencyName();
    }

    return $this->dependencies;
  }

  /**
   * {@inheritdoc}
   */
  public function onDependencyRemoval(array $dependencies) {
    // See if this target is responsible for any of the dependencies being
    // removed. If this is the case, indicate that the mapping that uses this
    // target needs to be removed from the feed type.
    $remove = FALSE;
    // Get all the current dependencies for this target.
    $current_dependencies = $this->calculateDependencies();
    foreach ($current_dependencies as $group => $dependency_list) {
      // Check if any of the target dependencies match the dependencies being
      // removed.
      foreach ($dependency_list as $config_key) {
        if (isset($dependencies[$group]) && array_key_exists($config_key, $dependencies[$group])) {
          // This targets dependency matches a dependency being removed,
          // indicate that mapping using this target needs to be removed.
          $remove = TRUE;
          break 2;
        }
      }
    }
    return $remove;
  }

  /**
   * {@inheritdoc}
   */
  public function defaultConfiguration() {
    $configuration = [];
    if ($this->isTargetFieldTranslatable()) {
      $configuration['language'] = NULL;
    }
    return $configuration;
  }

  /**
   * {@inheritdoc}
   */
  public function getSummary() {
    $summary = [];

    if (!$this->isMutable()) {
      $summary[] = $this->t('Read only');
    }

    if ($this->isTargetTranslatable()) {
      $language = $this->getLanguageManager()->getLanguage($this->configuration['language']);
      if ($language instanceof LanguageInterface) {
        $summary[] = $this->t('Language: @language', ['@language' => $language->getName()]);
      }
    }

    return $summary;
  }

  /**
   * {@inheritdoc}
   */
  public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
    if ($this->isTargetFieldTranslatable()) {
      $languages = $this->getLanguageManager()->getLanguages();
      $options = [
        '' => $this->t('Default'),
      ];
      foreach ($languages as $langcode => $language) {
        $options[$langcode] = $language->getName();
      }
      $language_default = !empty($this->configuration['language']) ? $this->configuration['language'] : '';
      $form['language'] = [
        '#title'   => $this->t('Language'),
        '#options' => $options,
        '#type'    => 'select',
        '#default_value' => $language_default,
      ];
    }
    return $form;
  }

  /**
   * Gets the language manager.
   *
   * @return \Drupal\Core\Language\LanguageManagerInterface
   *   The language manager.
   */
  protected function getLanguageManager() {
    if (!isset($this->languageManager)) {
      $this->setLanguageManager(\Drupal::service('language_manager'));
    }
    return $this->languageManager;
  }

  /**
   * Sets the language manager.
   *
   * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
   *   The language manager.
   */
  public function setLanguageManager(LanguageManagerInterface $language_manager) {
    $this->languageManager = $language_manager;
  }

  /**
   * {@inheritdoc}
   */
  public function languageExists() {
    return $this->getLanguageManager()->getLanguage($this->configuration['language']) instanceof LanguageInterface;
  }

  /**
   * {@inheritdoc}
   */
  public function isTargetTranslatable() {
    return $this->isTargetFieldTranslatable() && !empty($this->configuration['language']);
  }

  /**
   * Checks if the targeted field is translatable.
   *
   * @return bool
   *   True if the field is translatable. False otherwise.
   */
  protected function isTargetFieldTranslatable() {
    $field_storage = $this->targetDefinition->getFieldDefinition()->getFieldStorageDefinition();
    return !empty($field_storage) && $field_storage->isTranslatable();
  }

  /**
   * {@inheritdoc}
   */
  public function getLangcode() {
    if (!empty($this->configuration['language'])) {
      return $this->configuration['language'];
    }

    // Get the language from the processor, if the processor has one.
    $processor = $this->feedType->getProcessor();
    if ($processor instanceof EntityProcessorInterface) {
      return $processor->entityLanguage();
    }

    // Return default language.
    return $this->getLanguageManager()->getDefaultLanguage()->getId();
  }

}
