<?php

namespace Drupal\maintenance_2020_01\Plugin\Field\FieldFormatter;

use Drupal\Core\Field\FieldItemListInterface;
use Drupal\Core\Field\FormatterBase;
use Drupal\Core\Form\FormStateInterface;

/**
 * Plugin implementation of the 'Maintenance Documents' formatter.
 *
 * @FieldFormatter(
 *   id = "maintenance_documents",
 *   label = @Translation("Maintenance Documents"),
 *   field_types = {
 *     "file"
 *   }
 * )
 */
class MaintenanceDocumentsFormatter extends FormatterBase {

  /**
   * {@inheritdoc}
   */
  public static function defaultSettings() {
    return parent::defaultSettings();
  }

  /**
   * {@inheritdoc}
   */
  public function viewElements(FieldItemListInterface $items, $langcode) {
    $element = [];

    foreach ($items as $delta => $item) {
      $description = $item->getValue()['description'];
      $file = $item->entity;
      $created_timestamp = $file->get('created')->value;
      $element[$delta] = [
        '#theme' => 'file_link',
        '#file' => $file,
        '#description' => $description . ' (' . \Drupal::service('date.formatter')->format($created_timestamp, 'custom', 'Y.m.d') . ')',
        '#cache' => [
          'tags' => $file->getCacheTags(),
        ],
      ];
    }

    return $element;
  }

}