mpty( $scheme );
	}

	/**
	 * Determines whether the target URL ends with a slash and adds one if necessary.
	 *
	 * @param string $target_url The url to format.
	 *
	 * @return string The url with trailing slash.
	 */
	protected function trailingslashit( $target_url ) {
		// Adds slash to target URL when permalink structure ends with a slash.
		if ( $this->requires_trailing_slash( $target_url ) ) {
			return \trailingslashit( $target_url );
		}

		return $target_url;
	}

	/**
	 * Formats the target url for the multisite if needed.
	 *
	 * @param string $target_url The url to format.
	 *
	 * @return string The formatted url.
	 */
	protected function format_for_multisite( $target_url ) {
		if ( ! \is_multisite() ) {
			return $target_url;
		}

		$blog_details = \get_blog_details();
		if ( $blog_details && ! empty( $blog_details->path ) ) {
			$blog_path = \ltrim( $blog_details->path, '/' );
			if ( ! empty( $blog_path ) && \strpos( $target_url, $blog_path ) === 0 ) {
				$target_url = \substr( $target_url, \strlen( $blog_path ) );
			}
		}

		return $target_url;
	}

	/**
	 * Gets the redirect URL by given URL.
	 *
	 * @param string $redirect_url The URL that has to be redirected.
	 *
	 * @return string The redirect url.
	 */
	protected function home_url( $redirect_url ) {
		$redirect_url = $this->strip_subdirectory( $redirect_url );

		return \home_url( $redirect_url );
	}

	/**
	 * Strips the subdirectory from the given url.
	 *
	 * @param string $url The url to strip the subdirectory from.
	 *
	 * @return string The url with the stripped subdirectory.
	 */
	protected function strip_subdirectory( $url ) {
		return WPSEO_Redirect_Util::strip_base_url_path_from_url( $this->get_home_url(), $url );
	}

	/**
	 * Returns the URL PATH from the home url.
	 *
	 * @return string|null The url path or null if there isn't one.
	 */
	protected function get_home_url() {
		return \home_url();
	}

	/**
	 * Returns the redirects from the option table in the database.
	 *
	 * @return array The stored redirects.
	 */
	protected function get_redirects_from_options() {
		global $wpdb;
		static $redirects;

		if ( $redirects !== null ) {
			return $redirects;
		}

		// The code below is needed because we used to not autoload our redirect options. This fixes that.
		$all_options = \wp_cache_get( 'alloptions', 'options' );
		foreach ( [ $this->normal_option_name, $this->regex_option_name ] as $option ) {
			$redirects[ $option ] = isset( $all_options[ $option ] ) ? \maybe_unserialize( $all_options[ $option ] ) : false;
			if ( $redirects[ $option ] === false ) {
				$redirects[ $option ] = \get_option( $option, false );
				// phpcs:ignore WordPress.DB.DirectDatabaseQuery -- Normal methods only work if the option value has changed.
				$wpdb->update( $wpdb->options, [ 'autoload' => 'yes' ], [ 'option_name' => $option ] );
			}
		}

		return $redirects;
	}

	/**
	 * Sets the hook for setting the template include. This is the file that we want to show.
	 *
	 * @param string $template_to_set The template to look for.
	 *
	 * @return bool True when template should be included.
	 */
	protected function set_template_include_hook( $template_to_set ) {
		$this->template_file_path = $this->get_query_template( $template_to_set );
		if ( ! empty( $this->template_file_path ) ) {
			\add_filter( 'template_include', [ $this, 'set_template_include' ] );

			return true;
		}

		return false;
	}

	/**
	 * Wraps the WordPress status_header function.
	 *
	 * @param int    $code        HTTP status code.
	 * @param string $description Optional. A custom description for the HTTP status.
	 *
	 * @return void
	 */
	protected function status_header( $code, $description = '' ) {
		\status_header( $code, $description );
	}

	/**
	 * Returns instance of WP_Query.
	 *
	 * @return WP_Query Instance of WP_Query.
	 */
	protected function get_wp_query() {
		global $wp_query;

		if ( \is_object( $wp_query ) ) {
			return $wp_query;
		}

		return new WP_Query();
	}

	/**
	 * Handles the redirects without a target by setting the needed hooks.
	 *
	 * @param string $redirect_type The type of the redirect.
	 *
	 * @return void
	 */
	protected function handle_redirect_without_target( $redirect_type ) {
		if ( $redirect_type === 410 ) {
			\add_action( 'wp', [ $this, 'do_410' ] );
		}

		if ( $redirect_type === 451 ) {
			\add_action( 'wp', [ $this, 'do_451' ] );
		}
	}

	/**
	 * Wrapper method for doing the actual redirect.
	 *
	 * @param string $location The path to redirect to.
	 * @param int    $status   Status code to use.
	 *
	 * @return void
	 */
	protected function redirect( $location, $status = 302 ) {
		if ( ! \function_exists( 'wp_redirect' ) ) {
			require_once \ABSPATH . 'wp-includes/pluggable.php';
		}

		\wp_redirect( $location, $status, 'Yoast SEO Premium' );
		exit;
	}

	/**
	 * Returns whether or not a target URL requires a trailing slash.
	 *
	 * @param string $target_url The target URL to check.
	 *
	 * @return bool True when trailing slash is required.
	 */
	protected function requires_trailing_slash( $target_url ) {
		return WPSEO_Redirect_Util::requires_trailing_slash( $target_url );
	}

	/**
	 * Returns the query template.
	 *
	 * @param string $filename Filename without extension.
	 *
	 * @return string Full path to template file.
	 */
	protected function get_query_template( $filename ) {
		return \get_query_template( $filename );
	}
}