GPT 5.5 (paid)

<?php

declare(strict_types=1);

namespace Drupal\current_date_block\Plugin\Block;

use Drupal\Core\Block\Attribute\Block;
use Drupal\Core\Block\BlockBase;
use Drupal\Core\Block\BlockPluginInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;

/**
 * Provides a current date block.
 */
#[Block(
  id: 'current_date_block',
  admin_label: new TranslatableMarkup('Current date'),
)]
final class CurrentDateBlock extends BlockBase {

  /**
   * {@inheritdoc}
   */
  public function defaultConfiguration(): array {
    return [
      'label_display' => BlockPluginInterface::BLOCK_LABEL_VISIBLE,
      'date_format' => 'Y-m-d',
    ] + parent::defaultConfiguration();
  }

  /**
   * {@inheritdoc}
   */
  public function build(): array {
    $format = $this->configuration['date_format'] ?? 'Y-m-d';

    return [
      '#plain_text' => date($format),
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function blockForm($form, FormStateInterface $form_state): array {
    $form = parent::blockForm($form, $form_state);

    $form['date_format'] = [
      '#type' => 'textfield',
      '#title' => $this->t('Date format'),
      '#description' => $this->t('PHP date format string, for example: Y-m-d or d.m.Y H:i'),
      '#default_value' => $this->configuration['date_format'] ?? 'Y-m-d',
      '#required' => TRUE,
      '#maxlength' => 128,
    ];

    return $form;
  }

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

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

}