r( $redirect['host'] );

	/*
	 * Ignore differences in host capitalization, as this can lead to infinite redirects.
	 * Only redirect no-www <=> yes-www.
	 */
	if ( $original_host_low === $redirect_host_low
		|| ( 'www.' . $original_host_low !== $redirect_host_low
			&& 'www.' . $redirect_host_low !== $original_host_low )
	) {
		$redirect['host'] = $original['host'];
	}

	$compare_original = array( $original['host'], $original['path'] );

	if ( ! empty( $original['port'] ) ) {
		$compare_original[] = $original['port'];
	}

	if ( ! empty( $original['query'] ) ) {
		$compare_original[] = $original['query'];
	}

	$compare_redirect = array( $redirect['host'], $redirect['path'] );

	if ( ! empty( $redirect['port'] ) ) {
		$compare_redirect[] = $redirect['port'];
	}

	if ( ! empty( $redirect['query'] ) ) {
		$compare_redirect[] = $redirect['query'];
	}

	if ( $compare_original !== $compare_redirect ) {
		$redirect_url = $redirect['scheme'] . '://' . $redirect['host'];

		if ( ! empty( $redirect['port'] ) ) {
			$redirect_url .= ':' . $redirect['port'];
		}

		$redirect_url .= $redirect['path'];

		if ( ! empty( $redirect['query'] ) ) {
			$redirect_url .= '?' . $redirect['query'];
		}
	}

	if ( ! $redirect_url || $redirect_url === $requested_url ) {
		return;
	}

	// Hex-encoded octets are case-insensitive.
	if ( str_contains( $requested_url, '%' ) ) {
		if ( ! function_exists( 'lowercase_octets' ) ) {
			/**
			 * Converts the first hex-encoded octet match to lowercase.
			 *
			 * @since 3.1.0
			 * @ignore
			 *
			 * @param array $matches Hex-encoded octet matches for the requested URL.
			 * @return string Lowercased version of the first match.
			 */
			function lowercase_octets( $matches ) {
				return strtolower( $matches[0] );
			}
		}

		$requested_url = preg_replace_callback( '|%[a-fA-F0-9][a-fA-F0-9]|', 'lowercase_octets', $requested_url );
	}

	if ( $redirect_obj instanceof WP_Post ) {
		$post_status_obj = get_post_status_object( get_post_status( $redirect_obj ) );
		/*
		 * Unset the redirect object and URL if they are not readable by the user.
		 * This condition is a little confusing as the condition needs to pass if
		 * the post is not readable by the user. That's why there are ! (not) conditions
		 * throughout.
		 */
		if (
			// Private post statuses only redirect if the user can read them.
			! (
				$post_status_obj->private &&
				current_user_can( 'read_post', $redirect_obj->ID )
			) &&
			// For other posts, only redirect if publicly viewable.
			! is_post_publicly_viewable( $redirect_obj )
		) {
			$redirect_obj = false;
			$redirect_url = false;
		}
	}

	/**
	 * Filters the canonical redirect URL.
	 *
	 * Returning false to this filter will cancel the redirect.
	 *
	 * @since 2.3.0
	 *
	 * @param string $redirect_url  The redirect URL.
	 * @param string $requested_url The requested URL.
	 */
	$redirect_url = apply_filters( 'redirect_canonical', $redirect_url, $requested_url );

	// Yes, again -- in case the filter aborted the request.
	if ( ! $redirect_url || strip_fragment_from_url( $redirect_url ) === strip_fragment_from_url( $requested_url ) ) {
		return;
	}

	if ( $do_redirect ) {
		// Protect against chained redirects.
		if ( ! redirect_canonical( $redirect_url, false ) ) {
			wp_redirect( $redirect_url, 301 );
			exit;
		} else {
			// Debug.
			// die("1: $redirect_url<br />2: " . redirect_canonical( $redirect_url, false ) );
			return;
		}
	} else {
		return $redirect_url;
	}
}

/**
 * Removes arguments from a query string if they are not present in a URL
 * DO NOT use this in plugin code.
 *
 * @since 3.4.0
 * @access private
 *
 * @param string $query_string
 * @param array  $args_to_check
 * @param string $url
 * @return string The altered query string
 */
function _remove_qs_args_if_not_in_url( $query_string, array $args_to_check, $url ) {
	$parsed_url = parse_url( $url );

	if ( ! empty( $parsed_url['query'] ) ) {
		parse_str( $parsed_url['query'], $parsed_query );

		foreach ( $args_to_check as $qv ) {
			if ( ! isset( $parsed_query[ $qv ] ) ) {
				$query_string = remove_query_arg( $qv, $query_string );
			}
		}
	} else {
		$query_string = remove_query_arg( $args_to_check, $query_string );
	}

	return $query_string;
}

/**
 * Strips the #fragment from a URL, if one is present.
 *
 * @since 4.4.0
 *
 * @param string $url The URL to strip.
 * @return string The altered URL.
 */
function strip_fragment_from_url( $url ) {
	$parsed_url = wp_parse_url( $url );

	if ( ! empty( $parsed_url['host'] ) ) {
		$url = '';

		if ( ! empty( $parsed_url['scheme'] ) ) {
			$url = $parsed_url['scheme'] . ':';
		}

		$url .= '//' . $parsed_url['host'];

		if ( ! empty( $parsed_url['port'] ) ) {
			$url .= ':' . $parsed_url['port'];
		}

		if ( ! empty( $parsed_url['path'] ) ) {
			$url .= $parsed_url['path'];
		}

		if ( ! empty( $parsed_url['query'] ) ) {
			$url .= '?' . $parsed_url['query'];
		}
	}

	return $url;
}

/**
 * Attempts to guess the correct URL for a 404 request based on query vars.
 *
 * @since 2.3.0
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 *
 * @return string|false The correct URL if one is found. False on failure.
 */
function redirect_guess_404_permalink() {
	global $wpdb;

	/**
	 * Filters whether to attempt to guess a redirect URL for a 404 request.
	 *
	 * Returning a false value from the filter will disable the URL guessing
	 * and return early without performing a redirect.
	 *
	 * @since 5.5.0
	 *
	 * @param bool $do_redirect_guess Whether to attempt to guess a redirect URL
	 *                                for a 404 request. Default true.
	 */
	if ( false === apply_filters( 'do_redirect_guess_404_permalink', true ) ) {
		return false;
	}

	/**
	 * Short-circuits the redirect URL guessing for 404 requests.
	 *
	 * Returning a non-null value from the filter will effectively short-circuit
	 * the URL guessing, returning the passed value instead.
	 *
	 * @since 5.5.0
	 *
	 * @param null|string|false $pre Whether to short-circuit guessing the redirect for a 404.
	 *                               Default null to continue with the URL guessing.
	 */
	$pre = apply_filters( 'pre_redirect_guess_404_permalink', null );
	if ( null !== $pre ) {
		return $pre;
	}

	if ( get_query_var( 'name' ) ) {
		$publicly_viewable_statuses   = array_filter( get_post_stati(), 'is_post_status_viewable' );
		$publicly_viewable_post_types = array_filter( get_post_types( array( 'exclude_from_search' => false ) ), 'is_post_type_viewable' );

		/**
		 * Filters whether to perform a strict guess for a 404 redirect.
		 *
		 * Returning a truthy value from the filter will redirect only exact post_name matches.
		 *
		 * @since 5.5.0
		 *
		 * @param bool $strict_guess Whether to perform a strict guess. Default false (loose guess).
		 */
		$strict_guess = apply_filters( 'strict_redirect_guess_404_permalink', false );

		if ( $strict_guess ) {
			$where = $wpdb->prepare( 'post_name = %s', get_query_var( 'name' ) );
		} else {
			$where = $wpdb->prepare( 'post_name LIKE %s', $wpdb->esc_like( get_query_var( 'name' ) ) . '%' );
		}

		// If any of post_type, year, monthnum, or day are set, use them to refine the query.
		if ( get_query_var( 'post_type' ) ) {
			if ( is_array( get_query_var( 'post_type' ) ) ) {
				$post_types = array_intersect( get_query_var( 'post_type' ), $publicly_viewable_post_types );
				if ( empty( $post_types ) ) {
					return false;
				}
				$where .= " AND post_type IN ('" . join( "', '", esc_sql( get_query_var( 'post_type' ) ) ) . "')";
			} else {
				if ( ! in_array( get_query_var( 'post_type' ), $publicly_viewable_post_types, true ) ) {
					return false;
				}
				$where .= $wpdb->prepare( ' AND post_type = %s', get_query_var( 'post_type' ) );
			}
		} else {
			$where .= " AND post_type IN ('" . implode( "', '", esc_sql( $publicly_viewable_post_types ) ) . "')";
		}

		if ( get_query_var( 'year' ) ) {
			$where .= $wpdb->prepare( ' AND YEAR(post_date) = %d', get_query_var( 'year' ) );
		}
		if ( get_query_var( 'monthnum' ) ) {
			$where .= $wpdb->prepare( ' AND MONTH(post_date) = %d', get_query_var( 'monthnum' ) );
		}
		if ( get_query_var( 'day' ) ) {
			$where .= $wpdb->prepare( ' AND DAYOFMONTH(post_date) = %d', get_query_var( 'day' ) );
		}

		// phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
		$post_id = $wpdb->get_var( "SELECT ID FROM $wpdb->posts WHERE $where AND post_status IN ('" . implode( "', '", esc_sql( $publicly_viewable_statuses ) ) . "')" );

		if ( ! $post_id ) {
			return false;
		}

		if ( get_query_var( 'feed' ) ) {
			return get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );
		} elseif ( get_query_var( 'page' ) > 1 ) {
			return trailingslashit( get_permalink( $post_id ) ) . user_trailingslashit( get_query_var( 'page' ), 'single_paged' );
		} else {
			return get_permalink( $post_id );
		}
	}

	return false;
}

/**
 * Redirects a variety of shorthand URLs to the admin.
 *
 * If a user visits example.com/admin, they'll be redirected to /wp-admin.
 * Visiting /login redirects to /wp-login.php, and so on.
 *
 * @since 3.4.0
 *
 * @global WP_Rewrite $wp_rewrite WordPress rewrite component.
 */
function wp_redirect_admin_locations() {
	global $wp_rewrite;

	if ( ! ( is_404() && $wp_rewrite->using_permalinks() ) ) {
		return;
	}

	$admins = array(
		home_url( 'wp-admin', 'relative' ),
		home_url( 'dashboard', 'relative' ),
		home_url( 'admin', 'relative' ),
		site_url( 'dashboard', 'relative' ),
		site_url( 'admin', 'relative' ),
	);

	if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $admins, true ) ) {
		wp_redirect( admin_url() );
		exit;
	}

	$logins = array(
		home_url( 'wp-login.php', 'relative' ),
		home_url( 'login.php', 'relative' ),
		home_url( 'login', 'relative' ),
		site_url( 'login', 'relative' ),
	);

	if ( in_array( untrailingslashit( $_SERVER['REQUEST_URI'] ), $logins, true ) ) {
		wp_redirect( wp_login_url() );
		exit;
	}
}