<?php

namespace Drupal\block_test\Plugin\Block;

use Drupal\Core\Access\AccessResult;
use Drupal\Core\Block\BlockBase;
use Drupal\Core\Cache\Cache;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\State\StateInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Provides a block to test access.
 *
 * @Block(
 *   id = "test_access",
 *   admin_label = @Translation("Test block access")
 * )
 */
class TestAccessBlock extends BlockBase implements ContainerFactoryPluginInterface {

  /**
   * Tests the test access block.
   *
   *
   * @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\State\StateInterface $state
   *   The state.
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, StateInterface $state) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);

    $this->state = $state;
  }

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

  /**
   * {@inheritdoc}
   */
  protected function blockAccess(AccountInterface $account) {
    return $this->state->get('test_block_access', FALSE) ? AccessResult::allowed()->setCacheMaxAge(0) : AccessResult::forbidden()->setCacheMaxAge(0);
  }

  /**
   * {@inheritdoc}
   */
  public function build() {
    return ['#markup' => 'Hello test world'];
  }

  /**
   * {@inheritdoc}
   */
  public function getCacheMaxAge() {
    return Cache::PERMANENT;
  }

}