<?php

/**
 * @file
 * Provides token-based name displays for users.
 *
 * @todo Add a 'view realname' permission enabled by default
 * @todo Allow users to login with their real name
 * @todo Disable the username field
 */

use Drupal\Component\Utility\Html;
use Drupal\Component\Utility\Unicode;
use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Link;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Url;
use Drupal\user\Entity\User;

/**
 * @defgroup realname Real name API
 */

/**
 * Implements hook_help().
 */
function realname_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the Realname module.
    case 'realname.admin_settings_form':
    case 'help.page.realname':
      return '<p>' . t("A Real Name is what the site developer decides that users' names should look like. It is constructed from various tokens that are available within the site.") . '</p>';
  }
}

/**
 * Implements hook_entity_extra_field_info().
 */
function realname_entity_extra_field_info() {
  $fields['user']['user']['display']['realname'] = [
    'label' => t('Real name'),
    'description' => t('Real name'),
    'weight' => -1,
    'visible' => FALSE,
  ];

  return $fields;
}

/**
 * Implements hook_user_format_name_alter().
 */
function realname_user_format_name_alter(&$name, $account) {
  static $in_username_alter = FALSE;
  $uid = $account->id();

  // Don't alter anonymous users or objects that do not have any user ID.
  if (empty($uid)) {
    return;
  }

  // Real name was loaded/generated via hook_user_load(), so re-use it.
  if (isset($account->realname)) {
    if (Unicode::strlen($account->realname)) {
      // Only if the real name is a non-empty string is $name actually altered.
      $name = $account->realname;
    }
    return;
  }

  // Real name was not yet available for the account so we need to generate it.
  // Because tokens may call format_username() we need to prevent recursion.
  if (!$in_username_alter) {
    $in_username_alter = TRUE;

    // If $account->realname was undefined, then the user account object was
    // not properly loaded. We must enforce calling user_load().
    if ($realname_account = User::load($uid)) {
      realname_user_format_name_alter($name, $realname_account);
    }

    $in_username_alter = FALSE;
  }
}

/**
 * Implements hook_ENTITY_TYPE_load().
 */
function realname_user_load(array $accounts) {
  $realnames = realname_load_multiple($accounts);
  foreach ($realnames as $uid => $realname) {
    $accounts[$uid]->realname = $realname;
  }
}

/**
 * Implements hook_ENTITY_TYPE_update().
 */
function realname_user_update(EntityInterface $account) {
  // Since user data may have changed, update the realname and its cache.
  $realnames = &drupal_static('realname_load_multiple', []);
  $realnames[$account->id()] = realname_update($account);
}

/**
 * Implements hook_ENTITY_TYPE_delete().
 */
function realname_user_delete(EntityInterface $account) {
  realname_delete($account->id());
}

/**
 * Implements hook_ENTITY_TYPE_view() for user entities.
 */
function realname_user_view(array &$build, EntityInterface $account, EntityViewDisplayInterface $display, $view_mode) {
  if ($display->getComponent('realname')) {
    if ($account->access('view')) {
      $url = Url::fromRoute('entity.user.canonical', ['user' => $account->id()]);
      $markup = Link::fromTextAndUrl($account->realname, $url)->toString();
    }
    else {
      $markup = Html::escape($account->realname);
    }

    $build['realname'] = [
      '#theme' => 'field',
      '#title' => t('Real name'),
      '#label_display' => 'inline',
      '#view_mode' => '_custom',
      '#field_name' => 'realname',
      '#field_type' => 'text',
      '#field_translatable' => FALSE,
      '#entity_type' => 'custom',
      '#bundle' => 'custom',
      '#object' => $account,
      '#items' => [TRUE],
      '#is_multiple' => FALSE,
      0 => [
        '#markup' => $markup,
      ],
    ];
  }
}

/**
 * @addtogroup realname
 * @{
 */

/**
 * Loads a real name.
 *
 * @param Drupal\user\Entity\User $account
 *   A user account object.
 *
 * @return mixed
 *   The user's generated real name.
 */
function realname_load(User $account) {
  $realnames = realname_load_multiple([$account->id() => $account]);
  return reset($realnames);
}

/**
 * Loads multiple real names.
 *
 * @param array $accounts
 *   An array of user account objects keyed by user ID.
 *
 * @return array
 *   An array of real names keyed by user ID.
 */
function realname_load_multiple(array $accounts) {
  $realnames = &drupal_static(__FUNCTION__, []);

  if ($new_accounts = array_diff_key($accounts, $realnames)) {
    // Attempt to fetch realnames from the database first.
    $realnames += \Drupal::database()->query("SELECT uid, realname FROM {realname} WHERE uid IN (:uids[])", [':uids[]' => array_keys($new_accounts)])->fetchAllKeyed();

    // For each account that was not present in the database, generate its
    // real name.
    foreach ($new_accounts as $uid => $account) {
      if (!isset($realnames[$uid])) {
        $realnames[$uid] = realname_update($account);
      }
    }
  }

  return array_intersect_key($realnames, $accounts);
}

/**
 * Update the realname for a user account.
 *
 * @param Drupal\user\Entity\User $account
 *   A user account object.
 *
 * @return string
 *   A string with the real name.
 *
 * @see hook_realname_pattern_alter()
 * @see hook_realname_alter()
 * @see hook_realname_update()
 */
function realname_update(User $account) {
  $realname = '';

  if (!$account->isAnonymous()) {
    // Get the default pattern and allow other modules to alter it.
    $config = \Drupal::config('realname.settings');
    $pattern = $config->get('pattern');
    \Drupal::moduleHandler()->alter('realname_pattern', $pattern, $account);

    // Perform token replacement on the real name pattern.
    $realname = \Drupal::token()->replace($pattern, ['user' => $account], ['clear' => TRUE, 'sanitize' => FALSE]);

    // Remove any HTML tags.
    $realname = strip_tags(Html::decodeEntities($realname));

    // Remove double spaces (if a token had no value).
    $realname = preg_replace('/ {2,}/', ' ', $realname);

    // Allow other modules to alter the generated realname.
    \Drupal::moduleHandler()->alter('realname', $realname, $account);

    // The name must be trimmed to 255 characters before inserting into the
    // database.
    $realname = Unicode::truncate(trim($realname), 255);
  }
  else {
    // DisplayName cannot generated with tokens for anonymous users.
    $realname = $account->label();
  }

  // Save to the database and the static cache.
  \Drupal::database()->merge('realname')
    ->key(['uid' => $account->id()])
    ->fields([
      'realname' => $realname,
      'created' => \Drupal::time()->getRequestTime(),
    ])
    ->execute();

  // Allow modules to react to the realname being updated.
  \Drupal::moduleHandler()->invokeAll('realname_update', [$realname, $account]);

  // Clear the entity cache.
  /** @var \Drupal\user\UserStorageInterface $user_storage */
  $user_storage = \Drupal::getContainer()->get('entity.manager')->getStorage('user');
  $user_storage->resetCache([$account->id()]);

  return $realname;
}

/**
 * Delete a real name.
 *
 * @param int $uid
 *   A user ID.
 */
function realname_delete($uid) {
  return realname_delete_multiple([$uid]);
}

/**
 * Delete multiple real names.
 *
 * @param array $uids
 *   An array of user IDs.
 */
function realname_delete_multiple(array $uids) {
  \Drupal::database()->delete('realname')->condition('uid', $uids, 'IN')->execute();
  drupal_static_reset('realname_load_multiple');
  \Drupal::entityTypeManager()->getStorage('user')->resetCache($uids);
}

/**
 * Delete all real names.
 */
function realname_delete_all() {
  \Drupal::database()->truncate('realname')->execute();
  drupal_static_reset('realname_load_multiple');
  \Drupal::entityTypeManager()->getStorage('user')->resetCache();
}

/**
 * @} End of "addtogroup realname".
 */