<?php

namespace Drupal\Core\Entity\Controller;

use Drupal\Core\Entity\EntityDescriptionInterface;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\EntityRepositoryInterface;
use Drupal\Core\Entity\EntityTypeBundleInfoInterface;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Entity\EntityTypeInterface;
use Drupal\Core\Link;
use Drupal\Core\Render\RendererInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Routing\UrlGeneratorInterface;
use Drupal\Core\Routing\UrlGeneratorTrait;
use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
use Drupal\Core\StringTranslation\StringTranslationTrait;
use Drupal\Core\StringTranslation\TranslationInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Provides the add-page and title callbacks for entities.
 *
 * It provides:
 * - The add-page callback.
 * - An add title callback for entity types.
 * - An add title callback for entity types with bundles.
 * - A view title callback.
 * - An edit title callback.
 * - A delete title callback.
 */
class EntityController implements ContainerInjectionInterface {

  use StringTranslationTrait;
  use UrlGeneratorTrait;

  /**
   * The entity manager.
   *
   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
   */
  protected $entityTypeManager;

  /**
   * The entity type bundle info.
   *
   * @var \Drupal\Core\Entity\EntityTypeBundleInfoInterface
   */
  protected $entityTypeBundleInfo;

  /**
   * The entity repository.
   *
   * @var \Drupal\Core\Entity\EntityRepositoryInterface
   */
  protected $entityRepository;

  /**
   * The renderer.
   *
   * @var \Drupal\Core\Render\RendererInterface
   */
  protected $renderer;

  /**
   * Constructs a new EntityController.
   *
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   *   The entity type manager.
   * @param \Drupal\Core\Entity\EntityTypeBundleInfoInterface $entity_type_bundle_info
   *   The entity type bundle info.
   * @param \Drupal\Core\Entity\EntityRepositoryInterface $entity_repository
   *   The entity repository.
   * @param \Drupal\Core\Render\RendererInterface $renderer
   *   The renderer.
   * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
   *   The string translation.
   * @param \Drupal\Core\Routing\UrlGeneratorInterface $url_generator
   *   The url generator.
   */
  public function __construct(EntityTypeManagerInterface $entity_type_manager, EntityTypeBundleInfoInterface $entity_type_bundle_info, EntityRepositoryInterface $entity_repository, RendererInterface $renderer, TranslationInterface $string_translation, UrlGeneratorInterface $url_generator) {
    $this->entityTypeManager = $entity_type_manager;
    $this->entityTypeBundleInfo = $entity_type_bundle_info;
    $this->entityRepository = $entity_repository;
    $this->renderer = $renderer;
    $this->stringTranslation = $string_translation;
    $this->urlGenerator = $url_generator;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static(
      $container->get('entity_type.manager'),
      $container->get('entity_type.bundle.info'),
      $container->get('entity.repository'),
      $container->get('renderer'),
      $container->get('string_translation'),
      $container->get('url_generator')
    );
  }

  /**
   * Displays add links for the available bundles.
   *
   * Redirects to the add form if there's only one bundle available.
   *
   * @param string $entity_type_id
   *   The entity type ID.
   *
   * @return \Symfony\Component\HttpFoundation\RedirectResponse|array
   *   If there's only one available bundle, a redirect response.
   *   Otherwise, a render array with the add links for each bundle.
   */
  public function addPage($entity_type_id) {
    $entity_type = $this->entityTypeManager->getDefinition($entity_type_id);
    $bundles = $this->entityTypeBundleInfo->getBundleInfo($entity_type_id);
    $bundle_key = $entity_type->getKey('bundle');
    $bundle_entity_type_id = $entity_type->getBundleEntityType();
    $build = [
      '#theme' => 'entity_add_list',
      '#bundles' => [],
    ];
    if ($bundle_entity_type_id) {
      $bundle_argument = $bundle_entity_type_id;
      $bundle_entity_type = $this->entityTypeManager->getDefinition($bundle_entity_type_id);
      $bundle_entity_type_label = $bundle_entity_type->getLowercaseLabel();
      $build['#cache']['tags'] = $bundle_entity_type->getListCacheTags();

      // Build the message shown when there are no bundles.
      $link_text = $this->t('Add a new @entity_type.', ['@entity_type' => $bundle_entity_type_label]);
      $link_route_name = 'entity.' . $bundle_entity_type->id() . '.add_form';
      $build['#add_bundle_message'] = $this->t('There is no @entity_type yet. @add_link', [
        '@entity_type' => $bundle_entity_type_label,
        '@add_link' => Link::createFromRoute($link_text, $link_route_name)->toString(),
      ]);
      // Filter out the bundles the user doesn't have access to.
      $access_control_handler = $this->entityTypeManager->getAccessControlHandler($entity_type_id);
      foreach ($bundles as $bundle_name => $bundle_info) {
        $access = $access_control_handler->createAccess($bundle_name, NULL, [], TRUE);
        if (!$access->isAllowed()) {
          unset($bundles[$bundle_name]);
        }
        $this->renderer->addCacheableDependency($build, $access);
      }
      // Add descriptions from the bundle entities.
      $bundles = $this->loadBundleDescriptions($bundles, $bundle_entity_type);
    }
    else {
      $bundle_argument = $bundle_key;
    }

    $form_route_name = 'entity.' . $entity_type_id . '.add_form';
    // Redirect if there's only one bundle available.
    if (count($bundles) == 1) {
      $bundle_names = array_keys($bundles);
      $bundle_name = reset($bundle_names);
      return $this->redirect($form_route_name, [$bundle_argument => $bundle_name]);
    }
    // Prepare the #bundles array for the template.
    foreach ($bundles as $bundle_name => $bundle_info) {
      $build['#bundles'][$bundle_name] = [
        'label' => $bundle_info['label'],
        'description' => isset($bundle_info['description']) ? $bundle_info['description'] : '',
        'add_link' => Link::createFromRoute($bundle_info['label'], $form_route_name, [$bundle_argument => $bundle_name]),
      ];
    }

    return $build;
  }

  /**
   * Provides a generic add title callback for an entity type.
   *
   * @param string $entity_type_id
   *   The entity type ID.
   *
   * @return string
   *   The title for the entity add page.
   */
  public function addTitle($entity_type_id) {
    $entity_type = $this->entityTypeManager->getDefinition($entity_type_id);
    return $this->t('Add @entity-type', ['@entity-type' => $entity_type->getLowercaseLabel()]);
  }

  /**
   * Provides a generic add title callback for entities with bundles.
   *
   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
   *   The route match.
   * @param string $entity_type_id
   *   The entity type ID.
   * @param string $bundle_parameter
   *   The name of the route parameter that holds the bundle.
   *
   * @return string
   *   The title for the entity add page, if the bundle was found.
   */
  public function addBundleTitle(RouteMatchInterface $route_match, $entity_type_id, $bundle_parameter) {
    $bundles = $this->entityTypeBundleInfo->getBundleInfo($entity_type_id);
    // If the entity has bundle entities, the parameter might have been upcasted
    // so fetch the raw parameter.
    $bundle = $route_match->getRawParameter($bundle_parameter);
    if ((count($bundles) > 1) && isset($bundles[$bundle])) {
      return $this->t('Add @bundle', ['@bundle' => $bundles[$bundle]['label']]);
    }
    // If the entity supports bundles generally, but only has a single bundle,
    // the bundle is probably something like 'Default' so that it preferable to
    // use the entity type label.
    else {
      return $this->addTitle($entity_type_id);
    }
  }

  /**
   * Provides a generic title callback for a single entity.
   *
   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
   *   The route match.
   * @param \Drupal\Core\Entity\EntityInterface $_entity
   *   (optional) An entity, passed in directly from the request attributes.
   *
   * @return string|null
   *   The title for the entity view page, if an entity was found.
   */
  public function title(RouteMatchInterface $route_match, EntityInterface $_entity = NULL) {
    if ($entity = $this->doGetEntity($route_match, $_entity)) {
      return $entity->label();
    }
  }

  /**
   * Provides a generic edit title callback.
   *
   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
   *   The route match.
   * @param \Drupal\Core\Entity\EntityInterface $_entity
   *   (optional) An entity, passed in directly from the request attributes.
   *
   * @return string|null
   *   The title for the entity edit page, if an entity was found.
   */
  public function editTitle(RouteMatchInterface $route_match, EntityInterface $_entity = NULL) {
    if ($entity = $this->doGetEntity($route_match, $_entity)) {
      return $this->t('Edit %label', ['%label' => $entity->label()]);
    }
  }

  /**
   * Provides a generic delete title callback.
   *
   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
   *   The route match.
   * @param \Drupal\Core\Entity\EntityInterface $_entity
   *   (optional) An entity, passed in directly from the request attributes, and
   *   set in \Drupal\Core\Entity\Enhancer\EntityRouteEnhancer.
   *
   * @return string
   *   The title for the entity delete page.
   */
  public function deleteTitle(RouteMatchInterface $route_match, EntityInterface $_entity = NULL) {
    if ($entity = $this->doGetEntity($route_match, $_entity)) {
      return $this->t('Delete %label', ['%label' => $entity->label()]);
    }
  }

  /**
   * Determines the entity.
   *
   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
   *   The route match.
   * @param \Drupal\Core\Entity\EntityInterface $_entity
   *   (optional) The entity, set in
   *   \Drupal\Core\Entity\Enhancer\EntityRouteEnhancer.
   *
   * @return \Drupal\Core\Entity\EntityInterface|null
   *   The entity, if it is passed in directly or if the first parameter of the
   *   active route is an entity; otherwise, NULL.
   */
  protected function doGetEntity(RouteMatchInterface $route_match, EntityInterface $_entity = NULL) {
    if ($_entity) {
      $entity = $_entity;
    }
    else {
      // Let's look up in the route object for the name of upcasted values.
      foreach ($route_match->getParameters() as $parameter) {
        if ($parameter instanceof EntityInterface) {
          $entity = $parameter;
          break;
        }
      }
    }
    if (isset($entity)) {
      return $this->entityRepository->getTranslationFromContext($entity);
    }
  }

  /**
   * Expands the bundle information with descriptions, if known.
   *
   * @param array $bundles
   *   An array of bundle information.
   * @param \Drupal\Core\Entity\EntityTypeInterface $bundle_entity_type
   *   The bundle entity type definition.
   *
   * @return array
   *   The expanded array of bundle information.
   */
  protected function loadBundleDescriptions(array $bundles, EntityTypeInterface $bundle_entity_type) {
    if (!$bundle_entity_type->entityClassImplements(EntityDescriptionInterface::class)) {
      return $bundles;
    }
    $bundle_names = array_keys($bundles);
    $storage = $this->entityTypeManager->getStorage($bundle_entity_type->id());
    /** @var \Drupal\Core\Entity\EntityDescriptionInterface[] $bundle_entities */
    $bundle_entities = $storage->loadMultiple($bundle_names);
    foreach ($bundles as $bundle_name => &$bundle_info) {
      if (isset($bundle_entities[$bundle_name])) {
        $bundle_info['description'] = $bundle_entities[$bundle_name]->getDescription();
      }
    }

    return $bundles;
  }

}