Grok 4.5 (paid)

<?php

declare(strict_types=1);

namespace Drupal\current_date\Plugin\Block;

use Drupal\Component\Datetime\TimeInterface;
use Drupal\Core\Block\Attribute\Block;
use Drupal\Core\Block\BlockBase;
use Drupal\Core\Cache\Cache;
use Drupal\Core\Datetime\DateFormatterInterface;
use Drupal\Core\Entity\EntityStorageInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Provides a block that displays the current date.
 */
#[Block(
  id: 'current_date_block',
  admin_label: new TranslatableMarkup('Current date'),
  category: new TranslatableMarkup('Custom'),
)]
class CurrentDateBlock extends BlockBase implements ContainerFactoryPluginInterface {

  /**
   * Machine name of the custom date format option.
   */
  protected const CUSTOM_DATE_FORMAT = 'custom';

  /**
   * Constructs a CurrentDateBlock object.
   *
   * @param array $configuration
   *   A configuration array containing information about the plugin instance.
   * @param string $plugin_id
   *   The plugin ID for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   * @param \Drupal\Core\Datetime\DateFormatterInterface $dateFormatter
   *   The date formatter service.
   * @param \Drupal\Core\Entity\EntityStorageInterface $dateFormatStorage
   *   The date format entity storage.
   * @param \Drupal\Component\Datetime\TimeInterface $time
   *   The time service.
   */
  public function __construct(
    array $configuration,
    $plugin_id,
    $plugin_definition,
    protected DateFormatterInterface $dateFormatter,
    protected EntityStorageInterface $dateFormatStorage,
    protected TimeInterface $time,
  ) {
    parent::__construct($configuration, $plugin_id, $plugin_definition);
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition): static {
    return new static(
      $configuration,
      $plugin_id,
      $plugin_definition,
      $container->get('date.formatter'),
      $container->get('entity_type.manager')->getStorage('date_format'),
      $container->get('datetime.time'),
    );
  }

  /**
   * {@inheritdoc}
   */
  public function defaultConfiguration(): array {
    return [
      'label_display' => TRUE,
      'date_format' => 'medium',
      'custom_date_format' => '',
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function blockForm($form, FormStateInterface $form_state): array {
    $request_time = $this->time->getRequestTime();
    $date_formats = [];
    foreach ($this->dateFormatStorage->loadMultiple() as $machine_name => $date_format) {
      $date_formats[$machine_name] = $this->t('@name format: @date', [
        '@name' => $date_format->label(),
        '@date' => $this->dateFormatter->format($request_time, $machine_name),
      ]);
    }
    $date_formats[static::CUSTOM_DATE_FORMAT] = $this->t('Custom');

    $form['date_format'] = [
      '#type' => 'select',
      '#title' => $this->t('Date format'),
      '#options' => $date_formats,
      '#default_value' => $this->configuration['date_format'],
      '#required' => TRUE,
    ];

    $form['custom_date_format'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Custom date format'),
      '#description' => $this->t('See <a href="https://www.php.net/manual/datetime.format.php#refsect1-datetime.format-parameters" target="_blank">the documentation for PHP date formats</a>.'),
      '#default_value' => $this->configuration['custom_date_format'],
      '#states' => [
        'visible' => [
          ':input[name="settings[date_format]"]' => ['value' => static::CUSTOM_DATE_FORMAT],
        ],
        'required' => [
          ':input[name="settings[date_format]"]' => ['value' => static::CUSTOM_DATE_FORMAT],
        ],
      ],
    ];

    return $form;
  }

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

  /**
   * {@inheritdoc}
   */
  public function build(): array {
    $date_format = $this->configuration['date_format'];
    $custom_date_format = $date_format === static::CUSTOM_DATE_FORMAT
      ? ($this->configuration['custom_date_format'] ?? '')
      : '';

    $timestamp = $this->time->getRequestTime();
    $formatted = $this->dateFormatter->format($timestamp, $date_format, $custom_date_format);

    return [
      '#markup' => $formatted,
      '#cache' => [
        // Date changes every second; avoid caching a stale value for long.
        'max-age' => 0,
      ],
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function getCacheMaxAge(): int {
    return 0;
  }

  /**
   * {@inheritdoc}
   */
  public function getCacheTags(): array {
    $tags = parent::getCacheTags();
    $date_format = $this->configuration['date_format'] ?? '';
    if ($date_format !== '' && $date_format !== static::CUSTOM_DATE_FORMAT) {
      $tags = Cache::mergeTags($tags, ['config:core.date_format.' . $date_format]);
    }
    return $tags;
  }

}