<?php

/**
 * @file
 * Hook implementations for entity_browser_entity_form.module.
 *
 * Provides integration with the Inline entity form module.
 */

use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Field\FieldDefinitionInterface;
use Drupal\Core\Field\WidgetInterface;
use Drupal\Core\Url;
use Drupal\Component\Utility\NestedArray;
use Drupal\entity_browser\Element\EntityBrowserElement;
use Drupal\Core\Field\FieldStorageDefinitionInterface;
use Drupal\inline_entity_form\Plugin\Field\FieldWidget\InlineEntityFormComplex;

/**
 * Implements hook_inline_entity_form_reference_form_alter().
 */
function entity_browser_entity_form_inline_entity_form_reference_form_alter(&$reference_form, FormStateInterface &$form_state) {
  /** @var \Drupal\field\FieldConfigInterface $instance */
  $instance = $form_state->get([
    'inline_entity_form',
    $reference_form['#ief_id'],
    'instance',
  ]);

  /** @var \Drupal\Core\Entity\Display\EntityFormDisplayInterface $form_display */
  $entity_form_id = $instance->getTargetEntityTypeId() . '.' . $instance->getTargetBundle() . '.default';
  // TODO - 'default' might become configurable or something else in the future.
  // See https://www.drupal.org/node/2510274
  $form_display = \Drupal::entityTypeManager()->getStorage('entity_form_display')->load($entity_form_id);

  $widget = $form_display->getRenderer($instance->getName());

  $entity_browser_id = $widget->getThirdPartySetting('entity_browser_entity_form', 'entity_browser_id', '_none');
  if ($entity_browser_id === '_none') {
    return;
  }

  // Fetch the number of currently selected entities, if any.
  $count_existing_selection = count($form_state->get([
    'inline_entity_form',
    $reference_form['#ief_id'],
    'entities',
  ]));

  $cardinality = FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED;
  if ($instance->getFieldStorageDefinition()->get('cardinality') !== $cardinality) {
    $cardinality = $instance->getFieldStorageDefinition()->get('cardinality') - $count_existing_selection;
  }

  $bundles = $reference_form['entity_id']['#selection_settings']['target_bundles'];
  $target_entity_type = $reference_form['entity_id']['#target_type'];
  unset($reference_form['entity_id']);
  $reference_form['entity_browser'] = [
    '#type' => 'entity_browser',
    '#entity_browser' => $entity_browser_id,
    '#cardinality' => $cardinality,
    '#entity_browser_validators' => [
      'entity_type' => ['type' => $target_entity_type],
    ],
    '#widget_context' => [
      'target_bundles' => $bundles,
      'target_entity_type' => $target_entity_type,
      'cardinality' => $cardinality,
    ],
  ];
  $reference_form['#attached']['library'][] = 'entity_browser_entity_form/ief_autocomplete';
  $reference_form['actions']['ief_reference_save']['#ajax']['event'] = 'entities-selected';

  // Add custom validation and submit callbacks as we need to handle
  // multi-value cases.
  $reference_form['#element_validate'][0] = 'entity_browser_entity_form_reference_form_validate';
  $reference_form['#ief_element_submit'][0] = 'entity_browser_entity_form_reference_form_submit';
}

/**
 * Validates the form for adding existing entities.
 *
 * TODO see if we can get away without overriding entire IEF function.
 *
 * @param array $reference_form
 *   The reference entity form.
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 *   The form state of the parent form.
 *
 * @see inline_entity_form_reference_form_validate()
 */
function entity_browser_entity_form_reference_form_validate(array &$reference_form, FormStateInterface $form_state) {
  $form_values = NestedArray::getValue($form_state->getValues(), $reference_form['#parents']);
  if (empty($form_values['entity_browser']['entity_ids'])) {
    // The entity_id element is required, the value is empty only if
    // the form was cancelled.
    return;
  }
  $ief_id = $reference_form['#ief_id'];
  $labels = $reference_form['#ief_labels'];
  $attach_entities = EntityBrowserElement::processEntityIds($form_values['entity_browser']['entity_ids']);

  // Check if the entity is already referenced by the field.
  if (!empty($attach_entities)) {
    foreach ($attach_entities as $attach_entity) {
      foreach ($form_state->get(['inline_entity_form', $ief_id, 'entities']) as $key => $value) {
        if ($value['entity']->getEntityTypeId() == $attach_entity->getEntityTypeId() && $value['entity']->id() == $attach_entity->id()) {
          $form_state->setError($reference_form['entity_browser'], t('The selected @label has already been added.', ['@label' => $labels['singular']]));
          $reference_form['entity_browser']['entity_ids']['#value'] = '';
        }
      }
    }
  }
}

/**
 * Submits the form for adding existing entities.
 *
 * Adds the specified entity to the IEF form state.
 *
 * TODO see if we can get away without overriding entire IEF function.
 *
 * @param array $reference_form
 *   The reference entity form.
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 *   The form state of the parent form.
 *
 * @see inline_entity_form_reference_form_submit()
 */
function entity_browser_entity_form_reference_form_submit(array $reference_form, FormStateInterface $form_state) {
  $ief_id = $reference_form['#ief_id'];
  $form_values = NestedArray::getValue($form_state->getValues(), $reference_form['#parents']);
  $attach_entities = EntityBrowserElement::processEntityIds($form_values['entity_browser']['entity_ids']);
  $entities =& $form_state->get(['inline_entity_form', $ief_id, 'entities']);

  // Determine the correct weight of the new element.
  $weight = 0;
  if ($entities) {
    $weight = max(array_keys($entities)) + 1;
  }

  foreach ($attach_entities as $attach_entity) {
    $entities[] = [
      'entity' => $attach_entity,
      'weight' => $weight,
      'form' => NULL,
      'needs_save' => FALSE,
    ];
    $weight++;
  }
  $form_state->set(['inline_entity_form', $ief_id, 'entities'], $entities);

  // In some rare cases entity_ids keeps values of selected entities which then
  // causes problems in subsequent selections. Let's make sure it is empty and
  // ready for next usage of entity browser.
  $form_state->setValueForElement($reference_form['entity_browser']['entity_ids'], '');
  $input = &$form_state->getUserInput();
  NestedArray::unsetValue($input, array_merge($reference_form['#parents'], ['entity_browser', 'entity_ids']));
}

/**
 * Implements hook_field_widget_third_party_settings_form().
 */
function entity_browser_entity_form_field_widget_third_party_settings_form(WidgetInterface $plugin, FieldDefinitionInterface $field_definition, $form_mode, $form, FormStateInterface $form_state) {
  if ($plugin instanceof InlineEntityFormComplex) {
    $entity_browsers = \Drupal::service('entity_type.manager')->getStorage('entity_browser')->loadMultiple();
    if ($entity_browsers) {
      $options = [];
      foreach ($entity_browsers as $entity_browser) {
        $options[$entity_browser->id()] = $entity_browser->label();
      }
      $element['entity_browser_id'] = [
        '#type' => 'select',
        '#title' => t('Entity browser'),
        '#options' => $options,
        '#empty_option' => t('- None -'),
        '#empty_value' => '_none',
        '#default_value' => $plugin->getThirdPartySetting('entity_browser_entity_form', 'entity_browser_id'),
      ];
    }
    else {
      $element['message'] = [
        '#markup' => t('There are no entity browsers available. You can create one <a href="@url">here</a>.', ['@url' => Url::fromRoute('entity.entity_browser.collection')->toString()]),
      ];
    }
    return $element;
  }
}

/**
 * Implements hook_field_widget_settings_summary_alter().
 */
function entity_browser_entity_form_field_widget_settings_summary_alter(&$summary, $context) {
  $plugin = $context['widget'];
  if ($plugin instanceof InlineEntityFormComplex && $plugin->getThirdPartySetting('entity_browser_entity_form', 'entity_browser_id') && $plugin->getThirdPartySetting('entity_browser_entity_form', 'entity_browser_id') !== '_none') {
    $entity_browser_id = $plugin->getThirdPartySetting('entity_browser_entity_form', 'entity_browser_id');
    $entity_browser = \Drupal::service('entity_type.manager')->getStorage('entity_browser')->load($entity_browser_id);
    if ($entity_browser) {
      $summary[] = t('Entity browser: @entity_browser.', [
        '@entity_browser' => $entity_browser->label(),
      ]);
    }
    return $summary;
  }
}
