book_link_weight-1.0.0-beta1/src/Form/BookLinkWeightForm.php

<?php

namespace Drupal\book_link_weight\Form;

use Drupal\book\BookManagerInterface;
use Drupal\Core\Form\FormStateInterface;

/**
 * Book Link Weight form alterations.
 */
class BookLinkWeightForm {

  /**
   * The default delta for the book link weight drop-down.
   */
  const DEFAULT_DELTA = 20;


  /**
   * The book manager.
   *
   * @var Drupal\book\BookManagerInterface
   */
  protected $bookManager;

  /**
   * Create an instance of the book ui form.
   */
  public function __construct(BookManagerInterface $book_manager) {
    $this->bookManager = $book_manager;
  }

  /**
   * Alter the book outline element.
   */
  public function alterBookOutlineForm(&$form, FormStateInterface $form_state) {
    if (!empty($form['book']['bid']['#default_value']) && !empty($form['book']['pid']['#default_value'])) {
      $entity = $form_state->getformObject()->getEntity();
      $link = $this->bookManager->loadBookLink($form['book']['pid']['#default_value']);
      $subTree = [
        'below' => [],
      ];
      if ($link) {
        $parentTree = $this->bookManager->bookSubtreeData($link);
        $subTree = reset($parentTree);
      }

      $delta = self::DEFAULT_DELTA;
      if (!empty($subTree['below'])) {
        $count = count($subTree['below']);
        // Use 1.5 rather than 2 as the factor for the delta to give a bit more
        // breathing space in the re-ordering of elements, this logic kicks in
        // when there are more than 30 child pages.
        // @see BookAdminEditForm::bookAdminTableTree().
        $delta = ($count < 30) ? self::DEFAULT_DELTA : intval($count / 1.5) + 1;
      }

      $form['book']['pid'] += [
        '#ajax' => [
          'callback' => ['Drupal\book_link_weight\Form\BookLinkWeightForm', 'bookWeightTableUpdate'],
          'wrapper' => 'edit-book-weight-wrapper',
          'effect' => 'fade',
          'speed' => 'fast',
        ],
      ];

      $form['book']['pid']['#attributes']['class'][] = 'js-book-parent-select';

      $form['book']['table'] = [
        '#type' => 'table',
        '#header' => [
          'name' => t('Name'),
          'weight' => t('Weight'),
        ],
        '#prefix' => '<div id="edit-book-weight-wrapper">',
        '#suffix' => '</div>',
        '#id' => 'book-order',
        '#tabledrag' => [
          [
            'action' => 'order',
            'relationship' => 'sibling',
            'group' => 'book-item-weight',
          ],
        ],
      ];

      /*
       * Default the weight to 0, in case the parent has no previous children.
       * @see https://www.drupal.org/project/book_link_weight/issues/3195742
       */
      $lastWeight = 0;
      foreach ($subTree['below'] as $key => $item) {
        $form['book']['table'][$item['link']['nid']] = [
          '#attributes' => ['class' => ['draggable']],
          '#weight' => $item['link']['weight'],
          'name' => [
            '#markup' => $item['link']['title'],
          ],
          'weight' => [
            '#type' => 'weight',
            '#delta' => max($delta, abs($item['link']['weight'])),
            '#title' => t('Weight'),
            '#default_value' => $item['link']['weight'],
            '#title_display' => 'invisible',
            '#attributes' => ['class' => ['book-item-weight']],
          ],
        ];
        $lastWeight = $item['link']['weight'];
      }

      $currentTitle = $this->getCurrentTitle($form, $form_state);
      $nextRowWeight = $lastWeight + 1;
      $pageNid = 0;
      if (!$entity->isNew()) {
        $pageNid = $entity->id();
        if (isset($form['book']['table'][$pageNid])) {
          $nextRowWeight = $form['book']['table'][$pageNid]['weight']['#default_value'];
        }
      }
      $form['book']['table'][$pageNid] = [
        '#attributes' => ['class' => ['draggable']],
        '#weight' => $nextRowWeight,
        'name' => [
          '#markup' => "<span class='book-item-weight-current-item'>{$currentTitle}</span>",
        ],
        'weight' => [
          '#type' => 'weight',
          '#delta' => max($delta, abs($nextRowWeight)),
          '#title' => t('Weight'),
          '#default_value' => $nextRowWeight,
          '#title_display' => 'invisible',
          '#attributes' => ['class' => ['book-item-weight']],
        ],
      ];
    }
    else {
      /*
       * In the event of no parent being selected we just output the empty form
       * this allows it to be populated with content when a parent is selected.
       */
      $form['book']['table'] = [
        '#type' => 'table',
        '#header' => [
          'name' => t('Name'),
          'weight' => t('Weight'),
        ],
        '#attributes' => ['class' => ['visually-hidden']],
        '#prefix' => '<div id="edit-book-weight-wrapper">',
        '#suffix' => '</div>',
        '#id' => 'book-order',
        '#empty' => 'No sibling elements',
        '#tabledrag' => [
          [
            'action' => 'order',
            'relationship' => 'sibling',
            'group' => 'book-item-weight',
          ],
        ],
      ];
    }

    $form['book']['weight']['#type'] = 'hidden';

    $form['#attached']['library'][] = 'book_link_weight/book_link_weight';

    foreach (array_keys($form['actions']) as $action) {
      if ($action != 'preview' && isset($form['actions'][$action]['#type']) && $form['actions'][$action]['#type'] === 'submit') {
        array_unshift($form['actions'][$action]['#submit'], ['Drupal\book_link_weight\Form\BookLinkWeightForm', 'bookOutlineSubmit']);
      }
    }
  }

  /**
   * Get the current title from the node form.
   */
  protected function getCurrentTitle(array $form, FormStateInterface $form_state) {
    $form_id = $form['#form_id'];

    if ($form_state->getValue('title') && $form_state->getValue('title')[0]['value']) {
      return $form_state->getValue('title')[0]['value'];
    }
    elseif (!empty($form['title']['widget'][0]['value']['#default_value'])) {
      return $form['title']['widget'][0]['value']['#default_value'];
    }
    elseif (substr($form_id, 0, 4) === 'node' && substr($form_id, -17) === 'book_outline_form' && !empty($form['#title'])) {
      // This is the outline form on the outline page. The title lives in
      // a different key.
      return $form['#title'];
    }

    return t("Current page");
  }

  /**
   * Submit handler for saving book outline weight.
   *
   * @see alterBookOutlineForm()
   */
  public static function bookOutlineSubmit($form, FormStateInterface $form_state) {
    $bookManager = \Drupal::service('book.manager');
    $values = $form_state->getValues();

    if (!empty($values['book']['table'])) {
      foreach ($values['book']['table'] as $key => $item) {
        // A key of zero means a new node.
        // Using double equals for the second comparison because
        // $values[book][nid] is a string while key is a number.
        if ($key === 0 || $key == $values['book']['nid']) {
          // Set the weight of this node.
          $values['book']['weight'] = $item['weight'];
          $form_state->setValue('book', $values['book']);
        }
        else {
          // Update the weights of the sibling book links.
          $link = $bookManager->loadBookLink($key);
          $link['weight'] = $item['weight'];
          $bookManager->saveBookLink($link, FALSE);
        }
      }
    }
  }

  /**
   * Ajax function to update the node form book outline weight table.
   */
  public static function bookWeightTableUpdate($form, FormStateInterface $form_state) {
    return $form['book']['table'];
  }

}