ForumForm.php

<?php

namespace Drupal\forum\Form;

use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Link;
use Drupal\Core\Url;
use Drupal\taxonomy\TermForm;

/**
 * Base form for forum term edit forms.
 *
 * @internal
 */
class ForumForm extends TermForm {
    
    /**
     * Reusable type field to use in status messages.
     *
     * @var string
     */
    protected $forumFormType;
    
    /**
     * Reusable URL stub to use in watchdog messages.
     *
     * @var string
     */
    protected $urlStub = 'forum';
    
    /**
     * {@inheritdoc}
     */
    public function form(array $form, FormStateInterface $form_state) {
        // Build the bulk of the form from the parent taxonomy term form.
        $form = parent::form($form, $form_state);
        // Set the title and description of the name field.
        $form['name']['#title'] = $this->t('Forum name');
        $form['name']['#description'] = $this->t('Short but meaningful name for this collection of threaded discussions.');
        // Change the description.
        $form['description']['#description'] = $this->t('Description and guidelines for discussions within this forum.');
        // Re-use the weight field.
        $form['weight'] = $form['relations']['weight'];
        // Remove the remaining relations fields.
        unset($form['relations']);
        // Our parent field is different to the taxonomy term.
        $form['parent']['#tree'] = TRUE;
        $form['parent'][0] = $this->forumParentSelect($this->entity
            ->id(), $this->t('Parent'));
        $form['#theme_wrappers'] = [
            'form__forum',
        ];
        $this->forumFormType = $this->t('forum');
        return $form;
    }
    
    /**
     * {@inheritdoc}
     */
    public function buildEntity(array $form, FormStateInterface $form_state) {
        $term = parent::buildEntity($form, $form_state);
        // Assign parents from forum parent select field.
        $term->parent = [
            $form_state->getValue([
                'parent',
                0,
            ]),
        ];
        return $term;
    }
    
    /**
     * {@inheritdoc}
     */
    public function save(array $form, FormStateInterface $form_state) {
        $term = $this->entity;
        $term_storage = $this->entityTypeManager
            ->getStorage('taxonomy_term');
        $status = $term_storage->save($term);
        $route_name = $this->urlStub == 'container' ? 'entity.taxonomy_term.forum_edit_container_form' : 'entity.taxonomy_term.forum_edit_form';
        $route_parameters = [
            'taxonomy_term' => $term->id(),
        ];
        $link = Link::fromTextAndUrl($this->t('Edit'), new Url($route_name, $route_parameters))
            ->toString();
        $view_link = $term->toLink($term->getName())
            ->toString();
        switch ($status) {
            case SAVED_NEW:
                $this->messenger()
                    ->addStatus($this->t('Created new @type %term.', [
                    '%term' => $view_link,
                    '@type' => $this->forumFormType,
                ]));
                $this->logger('forum')
                    ->notice('Created new @type %term.', [
                    '%term' => $term->getName(),
                    '@type' => $this->forumFormType,
                    'link' => $link,
                ]);
                $form_state->setValue('tid', $term->id());
                break;
            case SAVED_UPDATED:
                $this->messenger()
                    ->addStatus($this->t('The @type %term has been updated.', [
                    '%term' => $term->getName(),
                    '@type' => $this->forumFormType,
                ]));
                $this->logger('forum')
                    ->notice('Updated @type %term.', [
                    '%term' => $term->getName(),
                    '@type' => $this->forumFormType,
                    'link' => $link,
                ]);
                break;
        }
        $form_state->setRedirect('forum.overview');
        return $term;
    }
    
    /**
     * {@inheritdoc}
     */
    protected function actions(array $form, FormStateInterface $form_state) {
        $actions = parent::actions($form, $form_state);
        if (!$this->entity
            ->isNew() && $this->entity
            ->hasLinkTemplate('forum-delete-form')) {
            $actions['delete']['#url'] = $this->entity
                ->toUrl('forum-delete-form');
        }
        else {
            unset($actions['delete']);
        }
        return $actions;
    }
    
    /**
     * Returns a select box for available parent terms.
     *
     * @param int $tid
     *   ID of the term that is being added or edited.
     * @param string $title
     *   Title for the select box.
     *
     * @return array
     *   A select form element.
     */
    protected function forumParentSelect($tid, $title) {
        $taxonomy_storage = $this->entityTypeManager
            ->getStorage('taxonomy_term');
        $parents = $taxonomy_storage->loadParents($tid);
        if ($parents) {
            $parent = array_shift($parents);
            $parent = $parent->id();
        }
        else {
            $parent = 0;
        }
        $vid = $this->config('forum.settings')
            ->get('vocabulary');
        $children = $taxonomy_storage->loadTree($vid, $tid, NULL, TRUE);
        // A term can't be the child of itself, nor of its children.
        foreach ($children as $child) {
            $exclude[] = $child->tid;
        }
        $exclude[] = $tid;
        $tree = $taxonomy_storage->loadTree($vid, 0, NULL, TRUE);
        $options[0] = '<' . $this->t('root') . '>';
        if ($tree) {
            foreach ($tree as $term) {
                if (!in_array($term->id(), $exclude)) {
                    $options[$term->id()] = str_repeat(' -- ', $term->depth) . $term->getName();
                }
            }
        }
        $description = $this->t('Forums may be placed at the top (root) level, or inside another container or forum.');
        return [
            '#type' => 'select',
            '#title' => $title,
            '#default_value' => $parent,
            '#options' => $options,
            '#description' => $description,
            '#required' => TRUE,
        ];
    }

}