<?php
namespace Drupal\dds_devel\Form;

use Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException;
use Drupal\Component\Plugin\Exception\PluginNotFoundException;
use Drupal\Core\Config\Entity\ConfigEntityType;
use Drupal\Core\Field\FieldItemList;
use Drupal\Core\Form\FormBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\entity_reference_revisions\Plugin\Field\FieldType\EntityReferenceRevisionsItem;
use Drupal\node\Entity\Node;
use Drupal\paragraphs\Entity\Paragraph;

class ParagraphUsageForm extends FormBase {

  /**
   * Returns a unique string identifying the form.
   *
   * The returned ID should be a unique string that can be a valid PHP function
   * name, since it's used in hook implementation names such as
   * hook_form_FORM_ID_alter().
   *
   * @return string
   *   The unique string identifying the form.
   */
  public function getFormId() {
    return 'dds_devel_paragraph_usage';
  }

  /**
   * Form constructor.
   *
   * @param array $form
   *   An associative array containing the structure of the form.
   * @param \Drupal\Core\Form\FormStateInterface $form_state
   *   The current state of the form.
   *
   * @return array
   *   The form structure.
   */
  public function buildForm(array $form, FormStateInterface $form_state) {
    $form = [];
    $type = $form_state->getValue('type');

    $paragraph_types = \Drupal::service('entity_type.bundle.info')->getBundleInfo('paragraph');
    $options = [];
    foreach ($paragraph_types as $paragraph_type_id => $paragraph_type) {
      $options[$paragraph_type_id] = $paragraph_type['label'];
    }
    $form['type'] = [
      '#type' => 'select',
      '#options' => $options,
      '#default_value' => $type
    ];
    $form['submit'] = [
      '#type' => 'submit',
      '#value' => $this->t('Find usage')
    ];

    if (!empty($type)) {
      $ids = \Drupal::entityQuery('paragraph')
        ->condition('type', $type)
        ->execute();

      try {
        $entities = \Drupal::entityTypeManager()->getStorage('paragraph')
          ->loadMultiple($ids);
      } catch (InvalidPluginDefinitionException $e) {
        // TODO: Error logging
      } catch (PluginNotFoundException $e) {
        // TODO: Error logging
      }

      while (!empty($ids)) {
        $ids = []; $new = [];
        /** @var Paragraph $paragraph */
        foreach ($entities as $id => $paragraph) {
          $parent = $paragraph->getParentEntity();
          if (!is_null($parent) && $parent->getEntityTypeId() == 'paragraph') {
            $new[$parent->id()] = $parent->id();
            unset($entities[$id]);
          }
        }

        if (!empty($new)) {
          foreach ($new as $id) {
            $ids[] = $id;
          }
          try {
            $new_entities = \Drupal::entityTypeManager()->getStorage('paragraph')
              ->loadMultiple($ids);
          } catch (InvalidPluginDefinitionException $e) {
            // TODO: Error logging
          } catch (PluginNotFoundException $e) {
            // TODO: Error logging
          }
          $entities += $new_entities;
        }
      }
      $ids = array_keys($entities);

      $form['list'] = array(
        '#type' => 'table',
        '#header' => array(
          t('Title'),
          t('Link'),
          t('Count'),
          t('Published')
        ),
        '#empty' => t('No usage was found.'),
        // TableSelect: Injects a first column containing the selection widget into
        // each table row.
        // Note that you also need to set #tableselect on each form submit button
        // that relies on non-empty selection values (see below).
        '#tableselect' => FALSE,
      );
      /** @var Paragraph $paragraph */
      foreach ($entities as $id => $paragraph) {
        $parent = $paragraph->getParentEntity();
        if (!is_null($parent) && $parent->getEntityTypeId() == 'node') {
          /** @var Node $node */
          $node = $parent;
          $count = $this->getCount($node, $type, $ids);
          if ($count > 0) {
            $form['list'][$node->id()]['title'] = [
              '#plain_text' => $node->label(),
            ];

            $alias = \Drupal::service('path.alias_manager')
              ->getAliasByPath('/node/' . $node->id());
            $url = customeredit_textToUrl($alias);
            if ($url !== FALSE) {
              $form['list'][$node->id()]['link'] = [
                '#type' => 'link',
                '#title' => $alias,
                '#url' => $url,
              ];
            }


            $form['list'][$node->id()]['count'] = [
              '#plain_text' => $count
            ];

            $form['list'][$node->id()]['published'] = [
              '#plain_text' => $node->isPublished() ? 'Published' : 'Unpublished'
            ];
          }

        }
      }
    } else {
      $form['list'] = [
        '#type' => 'hidden'
      ];
    }

    return $form;
  }

  /**
   * Form submission handler.
   *
   * @param array $form
   *   An associative array containing the structure of the form.
   * @param \Drupal\Core\Form\FormStateInterface $form_state
   *   The current state of the form.
   */
  public function submitForm(array &$form, FormStateInterface $form_state) {
    $form_state->setRebuild();
  }

  /**
   * @param \Drupal\node\Entity\Node $node
   * @param $type
   *
   * @return int
   */
  protected function getCount(Node $node, $type, $ids = []) {
    $count = 0;
    /** @var FieldItemList $field */
    foreach ($node->getFields() as $field) {
      if ($field->getFieldDefinition()->getType() == 'entity_reference_revisions') {
        /** @var \Drupal\entity_reference_revisions\EntityReferenceRevisionsFieldItemList $paragraphs */
        $paragraphs = $field;
        if ($paragraphs->getSetting('target_type') == 'paragraph') {
          /** @var EntityReferenceRevisionsItem $item */
          foreach ($paragraphs as $item) {
            if (!empty($item->getValue()['entity'])) {
              /** @var Paragraph $paragraph */
              $paragraph = $item->getValue()['entity'];
              if ($paragraph->bundle() == $type) {
                $count++;
              }
            } elseif (in_array($item->getValue()['target_id'], $ids)) {
              $count++;
            }
          }
        }
      }
    }
    return $count;
  }

}