<?php

namespace Drupal\dds\Service;

use Symfony\Component\HttpFoundation\Request;

class SessionService {

  /**
   * @var \Drupal\Core\TempStore\PrivateTempStore $privateTempStore
   *   The private temp store.
   */
  protected $privateTempStore;

  /**
   * @var \Drupal\Core\TempStore\SharedTempStore $sharedTempStore
   *   The shared temp store.
   */
  protected $sharedTempStore;

  /**
   * Get the temp store.
   *
   * This function allows you to get a tempstore, even for anonymous users if
   * you make sure that autostart session is allowed.
   *
   * @param string $type
   *   The tempstore type, can be either 'private' or 'shared'.
   * @param string $key
   *   The key for the tempstore to get.
   * @param bool $autostart_session
   *   (Optional, Default: True) Whether to start a session if one doesn't already exist.
   *
   * @return \Drupal\Core\TempStore\PrivateTempStore|\Drupal\Core\TempStore\SharedTempStore|bool
   *   Returns the tempstore if successful, otherwise returns FALSE.
   */
  public function getTempStore($type, $key, $autostart_session = TRUE) {
    // If the type specified is not private or shared, we return FALSE
    // to indicate we failed at getting the temp store.
    if (!in_array($type, ['private', 'shared'])) {
      return FALSE;
    }

    if ($autostart_session) {
      $this->startSession();
    }

    // Generate the property key.
    $tempstore_key = $type.'TempStore';
    // Generate the service name.
    $tempstore_service = 'user.' . $type . '_tempstore';

    /** @var \Drupal\Core\TempStore\PrivateTempStoreFactory|\Drupal\Core\TempStore\SharedTempStoreFactory $tempStoreFactory */
    $tempStoreFactory = \Drupal::service($tempstore_service);

    // If the tempstore is null, attempt to load it.
    if ($this->{$tempstore_key} === NULL) {
      $this->{$tempstore_key} = $tempStoreFactory->get($key);
    }

    // Return the tempstore if it exists, otherwise return FALSE.
    return !empty($this->{$tempstore_key})? $this->{$tempstore_key} : FALSE;
  }

  /**
   * Starts a session for the current request.
   *
   * If this function is called from CLI, it does not start a session.
   */
  public function startSession() {
    // If this is reached via PHP CLI, just return as it has no session.
    if (php_sapi_name() === 'cli') {
      return;
    }

    // We only need to handle creating sessions for anonymous users.
    if (\Drupal::currentUser()->isAnonymous()) {
      /** @var \Drupal\Core\Session\SessionManagerInterface $sessionManager */
      $sessionManager = \Drupal::service('session_manager');
      // Add a value to the session to make sure browsers garbage collection
      // doesn't remove it if it's empty.
      $_SESSION['dds_keep_session'] = TRUE;

      /** @var \Symfony\Component\HttpFoundation\RequestStack $requestStack */
      $requestStack = \Drupal::service('request_stack');
      // Only create session if the current request is null, as a session should
      // already exist if a current request exists.
      if ($requestStack->getCurrentRequest() === NULL) {
        /** @var \Symfony\Component\HttpFoundation\Session\SessionInterface $session */
        $session = \Drupal::service('session');

        // If session isn't started, migrate it to a new session so we keep all
        // our session variables.
        if (!$session->isStarted()) {
          $session->migrate();
        }

        // Create a new request from the globals.
        $request = Request::createFromGlobals();
        // Set the request session to the one we are using.
        $request->setSession($session);
      }

      // Start the session.
      $sessionManager->start();
    }
  }

}