<?php

namespace Drupal\custom_forms;

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Entity\EntityAccessControlHandler;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Session\AccountInterface;

/**
 * Defines the access control handler for the custom form entity type.
 */
class CustomFormHandlerAccessControlHandler extends EntityAccessControlHandler {

  /**
   * {@inheritdoc}
   */
  public function access(EntityInterface $entity, $operation, AccountInterface $account = NULL, $return_as_object = FALSE) {
    $account = $this->prepareUser($account);

    if ($account->hasPermission('bypass custom form access')) {
      $result = AccessResult::allowed()->cachePerPermissions();
      return $return_as_object ? $result : $result->isAllowed();
    }
    if (!$account->hasPermission('view published custom forms')) {
      $result = AccessResult::forbidden("The 'view published custom forms' permission is required.")->cachePerPermissions();
      return $return_as_object ? $result : $result->isAllowed();
    }
    $result = parent::access($entity, $operation, $account, TRUE)->cachePerPermissions();

    return $return_as_object ? $result : $result->isAllowed();
  }

  /**
   * {@inheritdoc}
   */
  public function createAccess($entity_bundle = NULL, AccountInterface $account = NULL, array $context = [], $return_as_object = FALSE) {
    $account = $this->prepareUser($account);

    if ($account->hasPermission('bypass custom form access')) {
      $result = AccessResult::allowed()->cachePerPermissions();
      return $return_as_object ? $result : $result->isAllowed();
    }
    if (!$account->hasPermission('view published custom forms')) {
      $result = AccessResult::forbidden("The 'view published custom forms' permission is required.")->cachePerPermissions();
      return $return_as_object ? $result : $result->isAllowed();
    }
    $result = parent::access($entity_bundle, $account, $context, TRUE)->cachePerPermissions();

    return $return_as_object ? $result : $result->isAllowed();
  }

  /**
   * {@inheritdoc}
   */
  protected function checkAccess(EntityInterface $custom_form, $operation, AccountInterface $account) {
    /** @var \Drupal\custom_forms\CustomFormInterface $custom_form */

    if ($account->hasPermission('bypass custom form access')) {
      return AccessResult::allowed()->cachePerPermissions();
    }

    // Fetch information from the custom form object if possible.
    $status = $custom_form->isPublished();
    $uid = $custom_form->getOwnerId();

    // Check if authors can view their own unpublished custom forms.
    if ($operation === 'view' && !$status && $account->hasPermission('view own unpublished custom forms') && $account->isAuthenticated() && $account->id() == $uid) {
      return AccessResult::allowed()->cachePerPermissions()->cachePerUser()->addCacheableDependency($custom_form);
    }

    switch ($operation) {
      case 'view':
        return AccessResult::allowedIfHasPermission($account, 'view published custom forms');

      case 'admin_view':
        return AccessResult::allowedIfHasPermissions($account, ['view custom form', 'edit custom form'], 'AND');

      case 'update':
        return AccessResult::allowedIfHasPermissions($account, ['edit custom form', 'administer custom form'], 'OR');

      case 'delete':
        return AccessResult::allowedIfHasPermissions($account, ['delete custom form', 'administer custom form'], 'OR');

      default:
        // No opinion.
        return AccessResult::neutral();
    }

  }

  /**
   * {@inheritdoc}
   */
  protected function checkCreateAccess(AccountInterface $account, array $context, $entity_bundle = NULL) {
    return AccessResult::allowedIf($account->hasPermission('create ' . $entity_bundle . ' custom form'))->cachePerPermissions();
  }

  /**
   * {@inheritdoc}
   */
  protected function checkFieldAccess($operation, FieldDefinitionInterface $field_definition, AccountInterface $account, FieldItemListInterface $items = NULL) {
    // Only users with the administer custom forms permission can edit
    // administrative fields.
    $administrative_fields = ['uid', 'status', 'created', 'promote', 'sticky'];
    if ($operation == 'edit' && in_array($field_definition->getName(), $administrative_fields, TRUE)) {
      return AccessResult::allowedIfHasPermission($account, 'administer custom forms');
    }

    // No user can change read only fields.
    $read_only_fields = ['revision_timestamp', 'revision_uid'];
    if ($operation == 'edit' && in_array($field_definition->getName(), $read_only_fields, TRUE)) {
      return AccessResult::forbidden();
    }

    // Users have access to the revision_log field either if they have
    // administrative permissions or if the new revision option is enabled.
    if ($operation == 'edit' && $field_definition->getName() == 'revision_log') {
      if ($account->hasPermission('administer custom forms')) {
        return AccessResult::allowed()->cachePerPermissions();
      }
      return AccessResult::allowedIf($items->getEntity()->type->entity->isNewRevision())->cachePerPermissions();
    }
    return parent::checkFieldAccess($operation, $field_definition, $account, $items);
  }

}