<?php

namespace Drupal\{{ machine_name }}\Plugin\Block;

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Block\BlockBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Session\AccountInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Provides a '{{ plugin_label }}' block.
 *
 * @Block(
 *   id = "{{ plugin_id }}",
 *   admin_label = @Translation("{{ plugin_label }}"),
 *   category = @Translation("{{ category }}")
 * )
 */
class {{ class }} extends BlockBase implements ContainerFactoryPluginInterface {

  /**
   * The route match.
   *
   * @var \Drupal\Core\Routing\RouteMatchInterface
   */
  protected $routeMatch;

  /**
   * Constructs a new {{ class }} instance.
   *
   * @param array $configuration
   *   The plugin configuration, i.e. an array with configuration values keyed
   *   by configuration option name. The special key 'context' may be used to
   *   initialize the defined contexts by setting it to an array of context
   *   values keyed by context names.
   * @param string $plugin_id
   *   The plugin_id for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
   *   The route match.
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, RouteMatchInterface $route_match) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
    $this->routeMatch = $route_match;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
    return new static(
      $configuration,
      $plugin_id,
      $plugin_definition,
      $container->get('current_route_match')
    );
  }

  /**
   * {@inheritdoc}
   */
  public function defaultConfiguration() {
    return [
      'content' => $this->t('Hello world!'),
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function blockForm($form, FormStateInterface $form_state) {
    $form['content'] = [
      '#type' => 'textarea',
      '#title' => $this->t('Block content'),
      '#default_value' => $this->configuration['content'],
    ];
    return $form;
  }

  /**
   * {@inheritdoc}
   */
  public function blockSubmit($form, FormStateInterface $form_state) {
    $this->configuration['content'] = $form_state->getValue('content');
  }

  /**
   * {@inheritdoc}
   *
   * @DCG Remove this method of you do not need any access restrictions.
   */
  protected function blockAccess(AccountInterface $account) {
    $route_name = $this->routeMatch->getRouteName();
    // Display the block only for anonymous users.
    if ($account->isAnonymous() && $route_name != 'user.register') {
      return AccessResult::allowed()
        ->addCacheContexts(['route.name', 'user.roles:anonymous']);
    }
    return AccessResult::forbidden();
  }

  /**
   * {@inheritdoc}
   */
  public function build() {
    $build['content'] = [
      '#markup' => $this->configuration['content'],
    ];
    return $build;
  }

}