<?php

/**
 * @file
 * Contains \Drupal\taxonomy\Plugin\field\field_type\TaxonomyTermReferenceItem.
 */

namespace Drupal\taxonomy\Plugin\Field\FieldType;

use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\Core\Field\Plugin\Field\FieldType\EntityReferenceItem;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Form\OptGroup;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\TypedData\OptionsProviderInterface;

/**
 * Plugin implementation of the 'term_reference' field type.
 *
 * @FieldType(
 *   id = "taxonomy_term_reference",
 *   label = @Translation("Term Reference"),
 *   description = @Translation("This field stores a reference to a taxonomy term."),
 *   default_widget = "options_select",
 *   default_formatter = "taxonomy_term_reference_link",
 *   list_class = "\Drupal\Core\Field\EntityReferenceFieldItemList",
 *   constraints = {"ValidReference" = {}}
 * )
 */
class TaxonomyTermReferenceItem extends EntityReferenceItem implements OptionsProviderInterface {

  /**
   * {@inheritdoc}
   */
  public static function defaultStorageSettings() {
    return array(
      'target_type' => 'taxonomy_term',
      'options_list_callback' => NULL,
      'allowed_values' => array(
        array(
          'vocabulary' => '',
          'parent' => 0,
        ),
      ),
    ) + parent::defaultStorageSettings();
  }

  /**
   * {@inheritdoc}
   */
  public function getPossibleValues(AccountInterface $account = NULL) {
    // Flatten options firstly, because Possible Options may contain group
    // arrays.
    $flatten_options = OptGroup::flattenOptions($this->getPossibleOptions($account));
    return array_keys($flatten_options);
  }

  /**
   * {@inheritdoc}
   */
  public function getPossibleOptions(AccountInterface $account = NULL) {
    return $this->getSettableOptions($account);
  }

  /**
   * {@inheritdoc}
   */
  public function getSettableValues(AccountInterface $account = NULL) {
    // Flatten options firstly, because Settable Options may contain group
    // arrays.
    $values = array_keys(OptGroup::flattenOptions($this->getSettableOptions($account)));
    $values[] = static::$NEW_ENTITY_MARKER;
    return $values;
  }

  /**
   * {@inheritdoc}
   */
  public function getSettableOptions(AccountInterface $account = NULL) {
    if ($callback = $this->getSetting('options_list_callback')) {
      return call_user_func_array($callback, array($this->getFieldDefinition(), $this->getEntity()));
    }
    else {
      $options = array();
      foreach ($this->getSetting('allowed_values') as $tree) {
        if ($vocabulary = entity_load('taxonomy_vocabulary', $tree['vocabulary'])) {
          if ($terms = taxonomy_get_tree($vocabulary->id(), $tree['parent'], NULL, TRUE)) {
            foreach ($terms as $term) {
              $options[$term->id()] = str_repeat('-', $term->depth) . $term->getName();
            }
          }
        }
      }
      return $options;
    }
  }

  /**
   * {@inheritdoc}
   */
  public static function schema(FieldStorageDefinitionInterface $field_definition) {
    return array(
      'columns' => array(
        'target_id' => array(
          'type' => 'int',
          'unsigned' => TRUE,
        ),
      ),
      'indexes' => array(
        'target_id' => array('target_id'),
      ),
      'foreign keys' => array(
        'target_id' => array(
          'table' => 'taxonomy_term_data',
          'columns' => array('target_id' => 'tid'),
        ),
      ),
    );
  }

  /**
   * {@inheritdoc}
   */
  public function storageSettingsForm(array &$form, FormStateInterface $form_state, $has_data) {
    $vocabularies = entity_load_multiple('taxonomy_vocabulary');
    $options = array();
    foreach ($vocabularies as $vocabulary) {
      $options[$vocabulary->id()] = $vocabulary->name;
    }

    $element = array();
    $element['#tree'] = TRUE;

    foreach ($this->getSetting('allowed_values') as $delta => $tree) {
      $element['allowed_values'][$delta]['vocabulary'] = array(
        '#type' => 'select',
        '#title' => t('Vocabulary'),
        '#default_value' => $tree['vocabulary'],
        '#options' => $options,
        '#required' => TRUE,
        '#description' => t('The vocabulary which supplies the options for this field.'),
        '#disabled' => $has_data,
      );
      $element['allowed_values'][$delta]['parent'] = array(
        '#type' => 'value',
        '#value' => $tree['parent'],
      );
    }

    return $element;
  }

  /**
   * {@inheritdoc}
   */
  public function fieldSettingsForm(array $form, FormStateInterface $form_state) {
    return array();
  }

}