<?php

/**
 * @file
 * Main file for the XML Sitemap engines.
 */

use Drupal\Component\Utility\UrlHelper;
use Drupal\Core\Routing\RouteMatchInterface;
use GuzzleHttp\Exception\RequestException;
use Drupal\Core\Cache\Cache;
use Drupal\Core\Url;

/**
 * Implements hook_hook_info().
 */
function xmlsitemap_engines_hook_info() {
  $hooks['xmlsitemap_engine_info'] = [
    'group' => 'xmlsitemap',
  ];
  $hooks['xmlsitemap_engine_info_alter'] = [
    'group' => 'xmlsitemap',
  ];
  return $hooks;
}

/**
 * Implements hook_help().
 */
function xmlsitemap_engines_help($route_name, RouteMatchInterface $route_match) {
  $output = '';

  switch ($route_name) {
    case 'xmlsitemap_engines.settings':
      break;
  }

  return $output;
}

/**
 * Implements hook_cron().
 */
function xmlsitemap_engines_cron() {
  if (xmlsitemap_engines_submit_access()) {
    xmlsitemap_engines_submit_engines();
  }
}

/**
 * Check if can submit.
 */
function xmlsitemap_engines_can_submit() {
  // Skip if the site is offline since search engines will not be able to
  // access the site's content.
  if (\Drupal::state()->get('system.maintenance_mode') || defined('MAINTENANCE_MODE')) {
    return FALSE;
  }

  if (!\Drupal::config('xmlsitemap_engines.settings')->get('engines') && !\Drupal::config('xmlsitemap_engines.settings')->get('custom_urls')) {
    return FALSE;
  }

  return TRUE;
}

/**
 * Submit access.
 */
function xmlsitemap_engines_submit_access() {
  if (!xmlsitemap_engines_can_submit()) {
    return FALSE;
  }

  $submit_updated = \Drupal::state()->get('xmlsitemap_engines_submit_updated');
  $submitted_last = \Drupal::state()->get('xmlsitemap_engines_submit_last');
  $minimum_lifetime = \Drupal::config('xmlsitemap_engines.settings')->get('minimum_lifetime');

  // Skip if sitemap data has not been updated since last submission.
  if ($submit_updated && \Drupal::state()->get('xmlsitemap_generated_last') <= $submitted_last) {
    return FALSE;
  }

  // Skip if the time since last submission is less than the minimum lifetime.
  if ((\Drupal::time()->getRequestTime() - $submitted_last) < $minimum_lifetime) {
    return FALSE;
  }

  return TRUE;
}

/**
 * Submit the sitemaps to all the specified search engines.
 *
 * @param array $smids
 *   An optional array of XML Sitemap IDs. If not provided, it will load all
 *   existing XML Sitemaps.
 */
function xmlsitemap_engines_submit_engines(array $smids = []) {
  if (empty($smids)) {
    $smids = FALSE;
  }

  $sitemaps = xmlsitemap_sitemap_load_multiple($smids);
  $engines = \Drupal::config('xmlsitemap_engines.settings')->get('engines');
  $engine_info = xmlsitemap_engines_get_engine_info();

  foreach ($engines as $engine) {
    if (isset($engine_info[$engine]['url'])) {
      xmlsitemap_engines_submit_sitemaps($engine_info[$engine]['url'], $sitemaps);
    }
  }

  $custom_urls = \Drupal::config('xmlsitemap_engines.settings')->get('custom_urls');
  $custom_urls = preg_split('/[\r\n]+/', $custom_urls, -1, PREG_SPLIT_NO_EMPTY);
  foreach ($custom_urls as $custom_url) {
    xmlsitemap_engines_submit_sitemaps($custom_url, $sitemaps);
  }

  \Drupal::state()->set('xmlsitemap_engines_submit_last', \Drupal::time()->getRequestTime());
}

/**
 * Submit the sitemaps to a specific URL.
 *
 * @param string $url
 *   The URL for sitemap submission.
 * @param array $sitemaps
 *   An array of URLs of the sitemaps to submit.
 */
function xmlsitemap_engines_submit_sitemaps($url, array $sitemaps) {
  foreach ($sitemaps as $sitemap) {
    $sitemap_path = UrlHelper::isExternal($sitemap->uri['path']) ? $sitemap->uri['path'] : 'base:/' . $sitemap->uri['path'];
    $sitemap_url = Url::fromUri($sitemap_path, $sitemap->uri['options'])->toString();
    $submit_url = xmlsitemap_engines_prepare_url($url, $sitemap_url);
    try {
      $request = \Drupal::httpClient()->get($submit_url);
      \Drupal::logger('xmlsitemap')->notice('Submitted the sitemap to %url and received response @code.', ['%url' => $submit_url, '@code' => $request->getStatusCode()]);
    }
    catch (RequestException $ex) {
      \Drupal::logger('xmlsitemap')->alert('Submitted the sitemap to %url and received response @code.', ['%url' => $submit_url, '@code' => '404']);
    }
  }
}

/**
 * Replace valid tokens in the URL with their appropriate values.
 *
 * @param string $url
 *   An un-tokenized URL.
 *
 * @return string
 *   A tokenized URL.
 */
function xmlsitemap_engines_prepare_url($url, $sitemap) {
  return str_replace('[sitemap]', $sitemap, $url);
}

/**
 * Returns information about supported search engines.
 *
 * @param string $engine
 *   (optional) The engine to return information for. If omitted, information
 *   for all engines is returned.
 *
 * @return string[]
 *   An array of supported search engines.
 *
 * @see hook_xmlsitemap_engines_info()
 * @see hook_xmlsitemap_engines_info_alter()
 */
function xmlsitemap_engines_get_engine_info($engine = NULL) {
  $language = \Drupal::languageManager()->getCurrentLanguage();
  $engines = &drupal_static(__FUNCTION__);

  if (!isset($engines)) {
    if ($cached = \Drupal::cache()->get('xmlsitemap:engines:' . $language->getId())) {
      $engines = $cached->data;
    }
    else {
      // Fetch the results of all hook_xmlsitemap_engine_info() implementations.
      $engines = \Drupal::moduleHandler()->invokeAll('xmlsitemap_engine_info');
      // Allow other modules to alter the engine info.
      \Drupal::moduleHandler()->alter('xmlsitemap_engine_info', $engines);
      // Cache by language since engine names are translated.
      \Drupal::cache()->set('xmlsitemap:engines:' . $language->getId(), $engines, Cache::PERMANENT, ['xmlsitemap']);
    }
  }

  if (isset($engine)) {
    return isset($engines[$engine]) ? $engines[$engine] : NULL;
  }
  else {
    return $engines;
  }
}

/**
 * Implements hook_xmlsitemap_engine_info().
 */
function xmlsitemap_engines_xmlsitemap_engine_info() {
  $engines['google'] = [
    'name' => t('Google'),
    'url' => 'https://www.google.com/ping?sitemap=[sitemap]',
    'help url' => 'https://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=156184',
  ];
  return $engines;
}

/**
 * Internal default state variables.
 */
function xmlsitemap_engines_state_variables() {
  $variables = [
    'xmlsitemap_engines_submit_last' => 0,
    'xmlsitemap_engines_submit_updated' => TRUE,
  ];
  return $variables;
}

/**
 * Implements hook_xmlsitemap_sitemap_operations().
 */
function xmlsitemap_engines_xmlsitemap_sitemap_operations() {
  if (xmlsitemap_engines_can_submit()) {
    $operations['xmlsitemap_engines_submit'] = [
      'label' => t('Submit to search engines'),
      'action past' => t('Submitted'),
      'callback' => 'xmlsitemap_engines_submit_engines',
    ];
    return $operations;
  }
}