wp_uninitialize_site() WordPress Function

function wp_uninitialize_site( $site_id ) {
	global $wpdb;

	if ( empty( $site_id ) ) {
		return new WP_Error( 'site_empty_id', __( 'Site ID must not be empty.' ) );
	}

	$site = get_site( $site_id );
	if ( ! $site ) {
		return new WP_Error( 'site_invalid_id', __( 'Site with the ID does not exist.' ) );
	}

	if ( ! wp_is_site_initialized( $site ) ) {
		return new WP_Error( 'site_already_uninitialized', __( 'The site appears to be already uninitialized.' ) );
	}

	$users = get_users(
		array(
			'blog_id' => $site->id,
			'fields'  => 'ids',
		)
	);

	// Remove users from the site.
	if ( ! empty( $users ) ) {
		foreach ( $users as $user_id ) {
			remove_user_from_blog( $user_id, $site->id );
		}
	}

	$switch = false;
	if ( get_current_blog_id() !== $site->id ) {
		$switch = true;
		switch_to_blog( $site->id );
	}

	$uploads = wp_get_upload_dir();

	$tables = $wpdb->tables( 'blog' );

	/**
	 * Filters the tables to drop when the site is deleted.
	 *
	 * @since MU (3.0.0)
	 *
	 * @param string[] $tables  Array of names of the site tables to be dropped.
	 * @param int      $site_id The ID of the site to drop tables for.
	 */
	$drop_tables = apply_filters( 'wpmu_drop_tables', $tables, $site->id );

	foreach ( (array) $drop_tables as $table ) {
		$wpdb->query( "DROP TABLE IF EXISTS `$table`" ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared
	}

	/**
	 * Filters the upload base directory to delete when the site is deleted.
	 *
	 * @since MU (3.0.0)
	 *
	 * @param string $basedir Uploads path without subdirectory. @see wp_upload_dir()
	 * @param int    $site_id The site ID.
	 */
	$dir     = apply_filters( 'wpmu_delete_blog_upload_dir', $uploads['basedir'], $site->id );
	$dir     = rtrim( $dir, DIRECTORY_SEPARATOR );
	$top_dir = $dir;
	$stack   = array( $dir );
	$index   = 0;

	while ( $index < count( $stack ) ) {
		// Get indexed directory from stack.
		$dir = $stack[ $index ];

		// phpcs:disable WordPress.PHP.NoSilencedErrors.Discouraged
		$dh = @opendir( $dir );
		if ( $dh ) {
			$file = @readdir( $dh );
			while ( false !== $file ) {
				if ( '.' === $file || '..' === $file ) {
					$file = @readdir( $dh );
					continue;
				}

				if ( @is_dir( $dir . DIRECTORY_SEPARATOR . $file ) ) {
					$stack[] = $dir . DIRECTORY_SEPARATOR . $file;
				} elseif ( @is_file( $dir . DIRECTORY_SEPARATOR . $file ) ) {
					@unlink( $dir . DIRECTORY_SEPARATOR . $file );
				}

				$file = @readdir( $dh );
			}
			@closedir( $dh );
		}
		$index++;
	}

	$stack = array_reverse( $stack ); // Last added directories are deepest.
	foreach ( (array) $stack as $dir ) {
		if ( $dir != $top_dir ) {
			@rmdir( $dir );
		}
	}

	// phpcs:enable WordPress.PHP.NoSilencedErrors.Discouraged
	if ( $switch ) {
		restore_current_blog();
	}

	return true;
}