function _wp_upload_dir( $time = null ) {
  $siteurl     = get_option( 'siteurl' );
  $upload_path = trim( get_option( 'upload_path' ) );

  if ( empty( $upload_path ) || 'wp-content/uploads' === $upload_path ) {
    $dir = WP_CONTENT_DIR . '/uploads';
  } elseif ( ! str_starts_with( $upload_path, ABSPATH ) ) {
    // $dir is absolute, $upload_path is (maybe) relative to ABSPATH.
    $dir = path_join( ABSPATH, $upload_path );
  } else {
    $dir = $upload_path;
  }

  $url = get_option( 'upload_url_path' );
  if ( ! $url ) {
    if ( empty( $upload_path ) || ( 'wp-content/uploads' === $upload_path ) || ( $upload_path === $dir ) ) {
      $url = WP_CONTENT_URL . '/uploads';
    } else {
      $url = trailingslashit( $siteurl ) . $upload_path;
    }
  }

  /*
	 * Honor the value of UPLOADS. This happens as long as ms-files rewriting is disabled.
	 * We also sometimes obey UPLOADS when rewriting is enabled -- see the next block.
	 */
  if ( defined( 'UPLOADS' ) && ! ( is_multisite() && get_site_option( 'ms_files_rewriting' ) ) ) {
    $dir = ABSPATH . UPLOADS;
    $url = trailingslashit( $siteurl ) . UPLOADS;
  }

  // If multisite (and if not the main site in a post-MU network).
  if ( is_multisite() && ! ( is_main_network() && is_main_site() && defined( 'MULTISITE' ) ) ) {

    if ( ! get_site_option( 'ms_files_rewriting' ) ) {
      /*
			 * If ms-files rewriting is disabled (networks created post-3.5), it is fairly
			 * straightforward: Append sites/%d if we're not on the main site (for post-MU
			 * networks). (The extra directory prevents a four-digit ID from conflicting with
			 * a year-based directory for the main site. But if a MU-era network has disabled
			 * ms-files rewriting manually, they don't need the extra directory, as they never
			 * had wp-content/uploads for the main site.)
			 */

      if ( defined( 'MULTISITE' ) ) {
        $ms_dir = '/sites/' . get_current_blog_id();
      } else {
        $ms_dir = '/' . get_current_blog_id();
      }

      $dir .= $ms_dir;
      $url .= $ms_dir;

    } elseif ( defined( 'UPLOADS' ) && ! ms_is_switched() ) {
      /*
			 * Handle the old-form ms-files.php rewriting if the network still has that enabled.
			 * When ms-files rewriting is enabled, then we only listen to UPLOADS when:
			 * 1) We are not on the main site in a post-MU network, as wp-content/uploads is used
			 *    there, and
			 * 2) We are not switched, as ms_upload_constants() hardcodes these constants to reflect
			 *    the original blog ID.
			 *
			 * Rather than UPLOADS, we actually use BLOGUPLOADDIR if it is set, as it is absolute.
			 * (And it will be set, see ms_upload_constants().) Otherwise, UPLOADS can be used, as
			 * as it is relative to ABSPATH. For the final piece: when UPLOADS is used with ms-files
			 * rewriting in multisite, the resulting URL is /files. (#WP22702 for background.)
			 */

      if ( defined( 'BLOGUPLOADDIR' ) ) {
        $dir = untrailingslashit( BLOGUPLOADDIR );
      } else {
        $dir = ABSPATH . UPLOADS;
      }
      $url = trailingslashit( $siteurl ) . 'files';
    }
  }

  $basedir = $dir;
  $baseurl = $url;

  $subdir = '';
  if ( get_option( 'uploads_use_yearmonth_folders' ) ) {
    // Generate the yearly and monthly directories.
    if ( ! $time ) {
      $time = current_time( 'mysql' );
    }
    $y      = substr( $time, 0, 4 );
    $m      = substr( $time, 5, 2 );
    $subdir = "/$y/$m";
  }

  $dir .= $subdir;
  $url .= $subdir;

  return array(
    'path'    => $dir,
    'url'     => $url,
    'subdir'  => $subdir,
    'basedir' => $basedir,
    'baseurl' => $baseurl,
    'error'   => false,
  );
}