class RequiredContextDelete

abstract class RequiredContextDelete extends ConfirmFormBase {
  
  /**
   * Creates a shared temporary storage for a collection.
   *
   * @var \Drupal\Core\TempStore\SharedTempStoreFactory
   */
  protected $tempstore;
  
  /**
   * The temporary id storage.
   *
   * @var string
   */
  // @codingStandardsIgnoreLine
  protected $tempstore_id;
  
  /**
   * The machine name.
   *
   * @var string
   */
  // @codingStandardsIgnoreLine
  protected $machine_name;
  
  /**
   * The id.
   *
   * @var int
   */
  protected $id;
  
  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static($container->get('tempstore.shared'));
  }
  
  /**
   * The constructor.
   *
   * @param \Drupal\Core\TempStore\SharedTempStoreFactory $tempstore
   *   The shared temporary storage.
   */
  public function __construct(SharedTempStoreFactory $tempstore) {
    $this->tempstore = $tempstore;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getFormId() {
    return 'ctools_required_context_delete';
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildForm(array $form, FormStateInterface $form_state, $id = NULL, $tempstore_id = NULL, $machine_name = NULL) {
    $this->tempstore_id = $tempstore_id;
    $this->machine_name = $machine_name;
    $this->id = $id;
    $cached_values = $this->tempstore
      ->get($this->tempstore_id)
      ->get($this->machine_name);
    $form['#title'] = $this->getQuestion($id, $cached_values);
    $form['#attributes']['class'][] = 'confirmation';
    $form['description'] = [
      '#markup' => $this->getDescription(),
    ];
    $form[$this->getFormName()] = [
      '#type' => 'hidden',
      '#value' => 1,
    ];
    // By default, render the form using theme_confirm_form().
    if (!isset($form['#theme'])) {
      $form['#theme'] = 'confirm_form';
    }
    $form['actions'] = [
      '#type' => 'actions',
    ];
    $form['actions'] += $this->actions($form, $form_state);
    return $form;
  }
  
  /**
   * {@inheritdoc}
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    $cached_values = $this->tempstore
      ->get($this->tempstore_id)
      ->get($this->machine_name);
    $contexts = $this->getContexts($cached_values);
    unset($contexts[$this->id]);
    $cached_values = $this->setContexts($cached_values, $contexts);
    $this->tempstore
      ->get($this->tempstore_id)
      ->set($this->machine_name, $cached_values);
    [$route_name, $route_parameters] = $this->getParentRouteInfo($cached_values);
    $form_state->setRedirect($route_name, $route_parameters);
  }
  
  /**
   * {@inheritdoc}
   */
  public function getQuestion($id = NULL, $cached_values = NULL) {
    $context = $this->getContexts($cached_values)[$id];
    return $this->t('Are you sure you want to delete the @label context?', [
      '@label' => $context['label'],
    ]);
  }
  
  /**
   * {@inheritdoc}
   */
  public function getDescription() {
    return $this->t('This action cannot be undone.');
  }
  
  /**
   * {@inheritdoc}
   */
  public function getFormName() {
    return 'confirm';
  }
  
  /**
   * Provides the action buttons for submitting this form.
   */
  protected function actions(array $form, FormStateInterface $form_state) {
    return [
      'submit' => [
        '#type' => 'submit',
        '#value' => $this->getConfirmText(),
        '#validate' => [
          [
            $this,
            'validate',
          ],
        ],
        '#submit' => [
          [
            $this,
            'submitForm',
          ],
        ],
      ],
      'cancel' => ConfirmFormHelper::buildCancelLink($this, $this->getRequest()),
    ];
  }
  
  /**
   * {@inheritdoc}
   */
  public function getCancelUrl() {
    $cached_values = $this->tempstore
      ->get($this->tempstore_id)
      ->get($this->machine_name);
    [$route_name, $route_parameters] = $this->getParentRouteInfo($cached_values);
    return new Url($route_name, $route_parameters);
  }
  
  /**
   * {@inheritdoc}
   */
  public function getConfirmText() {
    return $this->t('Delete');
  }
  
  /**
   * {@inheritdoc}
   */
  public function getCancelText() {
    return $this->t('Cancel');
  }
  
  /**
   * Document the route name and parameters for redirect after submission.
   *
   * @param mixed $cached_values
   *   The cached values.
   *
   * @return array
   *   In the format of
   *   return [
   *     'route.name',
   *     ['machine_name' => $this->machine_name,'step' => 'step_name],
   *   ];
   */
  abstract protected function getParentRouteInfo($cached_values);
  
  /**
   * Custom logic for retrieving the contexts array from cached_values.
   *
   * @param mixed $cached_values
   *   The cache values.
   *
   * @return array
   *   Return an array.
   */
  abstract protected function getContexts($cached_values);
  
  /**
   * Custom logic for setting the contexts array in cached_values.
   *
   * @param mixed $cached_values
   *   The cache values.
   * @param mixed $contexts
   *   The contexts to set within the cached values.
   *
   * @return mixed
   *   Return the $cached_values
   */
  abstract protected function setContexts($cached_values, $contexts);

}