<?php

/**
 * @file
 * Allows hiding of entity label fields and automatic label creation.
 */

use Drupal\auto_entitylabel\AutoEntityLabelManager;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\ContentEntityInterface;
use Drupal\Core\Url;
use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements hook_help().
 */
function auto_entitylabel_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.auto_entitylabel':
      $output = '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('This is a small and efficient module that allows hiding of entity label fields. To prevent empty labels it can be configured to generate the label automatically by a given pattern. The module can be used for any entity type that has a label, including e.g. for node titles, comment subjects, taxonomy term names and profile2 labels.') . '</p>';
      $output .= '<p>' . t('Patterns for automatic labels are constructed with the help of tokens. Drupal core provides a basic set of <a href="@url_tokens" target="blank">tokens</a>. For a token selection widget install the token. Some entity types (e.g. profile2) provide tokens via the entity_token, which is part of the entity module.', ['@url_tokens' => 'https://www.drupal.org/project/token']) . '</p>';
      $output .= '<p>' . t('Watch the <a href="@url_daily_dose_of_drupal" target="blank">Daily Dose of Drupal</a> screencast by <a href="@url_shane_thomas" target="blank">Shane Thomas</a> for a short introduction and demonstration of the module and some of its features. Demonstration made in D7 but can help a lot.', ['@url_daily_dose_of_drupal' => 'http://codekarate.com/daily-dose-of-drupal/drupal-7-automatic-entity-label-module', '@url_shane_thomas' => 'https://www.drupal.org/user/506260']) . '</p>';
      $output .= '<h3>' . t('Usage') . '</h3>';
      $output .= '<p>' . t('The configuration can be accessed with the <i>Manage automatic entity labels</i> operation or the <i>Automatic label</i> tab when editing entity types. For example, when configuring a node type, visit <i>Administration</i> » <i>Structure</i> » <i>Content types</i> (/admin/structure/types). You can also configure automatic labels for other entity types such as <i>Media<i>, in which case you would visit <i>Administration</i> » <i>Structure</i> » <i>Media</i> (/admin/structure/media).') . '</p>';
      return $output;
  }
}

/**
 * Implements hook_entity_type_alter().
 *
 * Adds the Auto Label tab to the entity configuration page.
 */
function auto_entitylabel_entity_type_alter(array &$entity_types) {
  /** @var \Drupal\Core\Entity\EntityTypeInterface $entity_type */
  foreach ($entity_types as $entity_type) {
    if ($entity_type->getBundleOf() && $entity_type->hasLinkTemplate('edit-form')) {
      $entity_type->setLinkTemplate('auto-label', $entity_type->getLinkTemplate('edit-form') . "/auto-label");
    }
  }
}

/**
 * Implements hook_form_alter().
 */
function auto_entitylabel_form_alter(&$form, FormStateInterface $form_state) {
  if (isset($form['#entity_builders'])) {
    /** @var \Drupal\Core\Entity\EntityFormInterface $formObject */
    $formObject = $form_state->getFormObject();
    $entity = $formObject->getEntity();
    if ($entity instanceof ContentEntityInterface) {
      auto_entitylabel_prepare_entityform($form, $entity);
    }
  }
}

/**
 * Implements hook_inline_entity_form_entity_form_alter().
 */
function auto_entitylabel_inline_entity_form_entity_form_alter(&$form, &$form_state) {
  $entity = $form['#entity'];
  auto_entitylabel_prepare_entityform($form, $entity);
}

/**
 * Implements hook_inline_entity_form_table_fields_alter().
 */
function auto_entitylabel_inline_entity_form_table_fields_alter(&$fields, $context) {
  // Replace label field behavior.
  if (isset($fields['label'])) {
    $fields['label']['type'] = 'callback';
    $fields['label']['callback'] = 'auto_entitylabel_inline_entity_label_callback';
  }
}

/**
 * A callback function to provide autoentitylabel for inline entity form.
 */
function auto_entitylabel_inline_entity_label_callback($entity, $variables) {
  $autolabel = $entity->label();
  if ($entity instanceof ContentEntityInterface) {
    $decorator = \Drupal::service('auto_entitylabel.entity_decorator');
    /** @var \Drupal\auto_entitylabel\AutoEntityLabelManager $decorated_entity */
    $decorated_entity = $decorator->decorate($entity);
    if ($decorated_entity->hasLabel() && $decorated_entity->autoLabelNeeded()) {
      $autolabel = $decorated_entity->setLabel();
    }

  }
  return $autolabel;
}

/**
 * Prepares the label replacement in the entity form.
 *
 * @param array $form
 *   Form array.
 * @param \Drupal\Core\Entity\ContentEntityInterface $entity
 *   The entity which title will be replaced.
 */
function auto_entitylabel_prepare_entityform(array &$form, ContentEntityInterface $entity) {
  if (empty($form['#auto_entitylabel_processed'])) {
    $decorator = \Drupal::service('auto_entitylabel.entity_decorator');
    /** @var \Drupal\auto_entitylabel\AutoEntityLabelManager $entity */
    $entity = $decorator->decorate($entity);
    $label = $entity->getLabelName();
    $widget = &$form[$label]['widget'][0];

    switch ($entity->getStatus()) {
      case AutoEntityLabelManager::ENABLED:
        // Hide the label field. It will be automatically generated in
        // hook_entity_presave().
        $widget['value']['#type'] = 'hidden';
        $widget['value']['#required'] = FALSE;
        if (empty($widget['value']['#default_value'])) {
          $widget['value']['#default_value'] = '%AutoEntityLabel%';
        }
        break;

      case AutoEntityLabelManager::OPTIONAL:
        // Allow label field to be empty. It will be automatically generated
        // in hook_entity_presave().
        $widget['value']['#required'] = FALSE;
        break;

      case AutoEntityLabelManager::PREFILLED:
        if (empty($widget['value']['#default_value'])) {
          $widget['value']['#default_value'] = $entity->setLabel();
        }
        break;
    }

    $form['#auto_entitylabel_processed'] = TRUE;
  }
}

/**
 * Implements hook_entity_prepare_view().
 */
function auto_entitylabel_entity_prepare_view($entity_type_id, array $entities, array $displays, $view_mode) {
  foreach ($entities as $entity) {
    if (isset($entity->in_preview) && $entity->in_preview === TRUE && $entity instanceof ContentEntityInterface) {
      $decorator = \Drupal::service('auto_entitylabel.entity_decorator');
      /** @var \Drupal\auto_entitylabel\AutoEntityLabelManager $decorated_entity */
      $decorated_entity = $decorator->decorate($entity);

      if ($decorated_entity->hasLabel() && $decorated_entity->autoLabelNeeded()) {
        $decorated_entity->setLabel();
      }
    }
  }
}

/**
 * Implements hook_entity_presave().
 */
function auto_entitylabel_entity_presave(EntityInterface $entity) {
  if ($entity instanceof ContentEntityInterface) {
    $decorator = \Drupal::service('auto_entitylabel.entity_decorator');
    /** @var \Drupal\auto_entitylabel\AutoEntityLabelManager $decorated_entity */
    $decorated_entity = $decorator->decorate($entity);
    if ($decorated_entity->hasLabel() && $decorated_entity->autoLabelNeeded()
      && !$decorated_entity->isTitlePreserved()) {
      $decorated_entity->setLabel();
    }
  }
}

/**
 * Implements hook_entity_insert().
 */
function auto_entitylabel_entity_insert(EntityInterface $entity) {
  if ($entity instanceof ContentEntityInterface) {
    $decorator = \Drupal::service('auto_entitylabel.entity_decorator');
    /** @var \Drupal\auto_entitylabel\AutoEntityLabelManager $decorated_entity */
    $decorated_entity = $decorator->decorate($entity);
    if ($decorated_entity->hasLabel()
      && (
        $decorated_entity->hasAutoLabel()
        || empty($entity->label()) && $decorated_entity->hasOptionalAutoLabel()
      )
    ) {
      if ($entity->getEntityType()->isRevisionable()) {
        $entity->setNewRevision(FALSE);
      }
      $entity->save();
    }
  }
}

/**
 * Implements hook_validation_constraint_alter().
 *
 * Override core NotNull constraint to allow entities that use Auto Entity
 * Labels to validate when their label is empty before being set automatically.
 */
function auto_entitylabel_validation_constraint_alter(array &$definitions) {
  $definitions['NotNull']['class'] = 'Drupal\auto_entitylabel\Plugin\Validation\EntityLabelNotNullConstraint';
}

/**
 * Implements hook_entity_operation().
 */
function auto_entitylabel_entity_operation(EntityInterface $entity) {
  $operations = [];
  $entity_type = $entity->getEntityType();
  $entity_type_id = $entity_type->id();
  $entity_id = $entity->id();
  if ($entity->hasLinkTemplate('auto-label') &&
    \Drupal::currentUser()->hasPermission('administer ' . $entity_type_id . ' labels')) {

    $operations['auto-label'] = [
      'title' => t('Manage automatic entity labels'),
      'weight' => 100,
      'url' => Url::fromRoute("entity.{$entity_type_id}.auto_label", [$entity_type_id => $entity_id]),
    ];
  }

  return $operations;
}