allows hosts to send users directly to
 * the page where they can update their site to use HTTPS.
 *
 * @since 5.7.0
 *
 * @return string URL for directly updating to HTTPS or empty string.
 */
function wp_get_direct_update_https_url() {
	$direct_update_url = '';

	if ( false !== getenv( 'WP_DIRECT_UPDATE_HTTPS_URL' ) ) {
		$direct_update_url = getenv( 'WP_DIRECT_UPDATE_HTTPS_URL' );
	}

	/**
	 * Filters the URL for directly updating the PHP version the site is running on from the host.
	 *
	 * @since 5.7.0
	 *
	 * @param string $direct_update_url URL for directly updating PHP.
	 */
	$direct_update_url = apply_filters( 'wp_direct_update_https_url', $direct_update_url );

	return $direct_update_url;
}

/**
 * Gets the size of a directory.
 *
 * A helper function that is used primarily to check whether
 * a blog has exceeded its allowed upload space.
 *
 * @since MU (3.0.0)
 * @since 5.2.0 $max_execution_time parameter added.
 *
 * @param string $directory Full path of a directory.
 * @param int    $max_execution_time Maximum time to run before giving up. In seconds.
 *                                   The timeout is global and is measured from the moment WordPress started to load.
 * @return int|false|null Size in bytes if a valid directory. False if not. Null if timeout.
 */
function get_dirsize( $directory, $max_execution_time = null ) {

	/*
	 * Exclude individual site directories from the total when checking the main site of a network,
	 * as they are subdirectories and should not be counted.
	 */
	if ( is_multisite() && is_main_site() ) {
		$size = recurse_dirsize( $directory, $directory . '/sites', $max_execution_time );
	} else {
		$size = recurse_dirsize( $directory, null, $max_execution_time );
	}

	return $size;
}

/**
 * Gets the size of a directory recursively.
 *
 * Used by get_dirsize() to get a directory size when it contains other directories.
 *
 * @since MU (3.0.0)
 * @since 4.3.0 The `$exclude` parameter was added.
 * @since 5.2.0 The `$max_execution_time` parameter was added.
 * @since 5.6.0 The `$directory_cache` parameter was added.
 *
 * @param string          $directory          Full path of a directory.
 * @param string|string[] $exclude            Optional. Full path of a subdirectory to exclude from the total,
 *                                            or array of paths. Expected without trailing slash(es).
 *                                            Default null.
 * @param int             $max_execution_time Optional. Maximum time to run before giving up. In seconds.
 *                                            The timeout is global and is measured from the moment
 *                                            WordPress started to load. Defaults to the value of
 *                                            `max_execution_time` PHP setting.
 * @param array           $directory_cache    Optional. Array of cached directory paths.
 *                                            Defaults to the value of `dirsize_cache` transient.
 * @return int|false|null Size in bytes if a valid directory. False if not. Null if timeout.
 */
function recurse_dirsize( $directory, $exclude = null, $max_execution_time = null, &$directory_cache = null ) {
	$directory  = untrailingslashit( $directory );
	$save_cache = false;

	if ( ! isset( $directory_cache ) ) {
		$directory_cache = get_transient( 'dirsize_cache' );
		$save_cache      = true;
	}

	if ( isset( $directory_cache[ $directory ] ) && is_int( $directory_cache[ $directory ] ) ) {
		return $directory_cache[ $directory ];
	}

	if ( ! file_exists( $directory ) || ! is_dir( $directory ) || ! is_readable( $directory ) ) {
		return false;
	}

	if (
		( is_string( $exclude ) && $directory === $exclude ) ||
		( is_array( $exclude ) && in_array( $directory, $exclude, true ) )
	) {
		return false;
	}

	if ( null === $max_execution_time ) {
		// Keep the previous behavior but attempt to prevent fatal errors from timeout if possible.
		if ( function_exists( 'ini_get' ) ) {
			$max_execution_time = ini_get( 'max_execution_time' );
		} else {
			// Disable...
			$max_execution_time = 0;
		}

		// Leave 1 second "buffer" for other operations if $max_execution_time has reasonable value.
		if ( $max_execution_time > 10 ) {
			$max_execution_time -= 1;
		}
	}

	/**
	 * Filters the amount of storage space used by one directory and all its children, in megabytes.
	 *
	 * Return the actual used space to short-circuit the recursive PHP file size calculation
	 * and use something else, like a CDN API or native operating system tools for better performance.
	 *
	 * @since 5.6.0
	 *
	 * @param int|false            $space_used         The amount of used space, in bytes. Default false.
	 * @param string               $directory          Full path of a directory.
	 * @param string|string[]|null $exclude            Full path of a subdirectory to exclude from the total,
	 *                                                 or array of paths.
	 * @param int                  $max_execution_time Maximum time to run before giving up. In seconds.
	 * @param array                $directory_cache    Array of cached directory paths.
	 */
	$size = apply_filters( 'pre_recurse_dirsize', false, $directory, $exclude, $max_execution_time, $directory_cache );

	if ( false === $size ) {
		$size = 0;

		$handle = opendir( $directory );
		if ( $handle ) {
			while ( ( $file = readdir( $handle ) ) !== false ) {
				$path = $directory . '/' . $file;
				if ( '.' !== $file && '..' !== $file ) {
					if ( is_file( $path ) ) {
						$size += filesize( $path );
					} elseif ( is_dir( $path ) ) {
						$handlesize = recurse_dirsize( $path, $exclude, $max_execution_time, $directory_cache );
						if ( $handlesize > 0 ) {
							$size += $handlesize;
						}
					}

					if ( $max_execution_time > 0 &&
						( microtime( true ) - WP_START_TIMESTAMP ) > $max_execution_time
					) {
						// Time exceeded. Give up instead of risking a fatal timeout.
						$size = null;
						break;
					}
				}
			}
			closedir( $handle );
		}
	}

	if ( ! is_array( $directory_cache ) ) {
		$directory_cache = array();
	}

	$directory_cache[ $directory ] = $size;

	// Only write the transient on the top level call and not on recursive calls.
	if ( $save_cache ) {
		$expiration = ( wp_using_ext_object_cache() ) ? 0 : 10 * YEAR_IN_SECONDS;
		set_transient( 'dirsize_cache', $directory_cache, $expiration );
	}

	return $size;
}

/**
 * Cleans directory size cache used by recurse_dirsize().
 *
 * Removes the current directory and all parent directories from the `dirsize_cache` transient.
 *
 * @since 5.6.0
 * @since 5.9.0 Added input validation with a notice for invalid input.
 *
 * @param string $path Full path of a directory or file.
 */
function clean_dirsize_cache( $path ) {
	if ( ! is_string( $path ) || empty( $path ) ) {
		wp_trigger_error(
			'',
			sprintf(
				/* translators: 1: Function name, 2: A variable type, like "boolean" or "integer". */
				__( '%1$s only accepts a non-empty path string, received %2$s.' ),
				'<code>clean_dirsize_cache()</code>',
				'<code>' . gettype( $path ) . '</code>'
			)
		);
		return;
	}

	$directory_cache = get_transient( 'dirsize_cache' );

	if ( empty( $directory_cache ) ) {
		return;
	}

	$expiration = ( wp_using_ext_object_cache() ) ? 0 : 10 * YEAR_IN_SECONDS;
	if (
		! str_contains( $path, '/' ) &&
		! str_contains( $path, '\\' )
	) {
		unset( $directory_cache[ $path ] );
		set_transient( 'dirsize_cache', $directory_cache, $expiration );
		return;
	}

	$last_path = null;
	$path      = untrailingslashit( $path );
	unset( $directory_cache[ $path ] );

	while (
		$last_path !== $path &&
		DIRECTORY_SEPARATOR !== $path &&
		'.' !== $path &&
		'..' !== $path
	) {
		$last_path = $path;
		$path      = dirname( $path );
		unset( $directory_cache[ $path ] );
	}

	set_transient( 'dirsize_cache', $directory_cache, $expiration );
}

/**
 * Checks compatibility with the current WordPress version.
 *
 * @since 5.2.0
 *
 * @global string $wp_version The WordPress version string.
 *
 * @param string $required Minimum required WordPress version.
 * @return bool True if required version is compatible or empty, false if not.
 */
function is_wp_version_compatible( $required ) {
	global $wp_version;

	// Strip off any -alpha, -RC, -beta, -src suffixes.
	list( $version ) = explode( '-', $wp_version );

	if ( is_string( $required ) ) {
		$trimmed = trim( $required );

		if ( substr_count( $trimmed, '.' ) > 1 && str_ends_with( $trimmed, '.0' ) ) {
			$required = substr( $trimmed, 0, -2 );
		}
	}

	return empty( $required ) || version_compare( $version, $required, '>=' );
}

/**
 * Checks compatibility with the current PHP version.
 *
 * @since 5.2.0
 *
 * @param string $required Minimum required PHP version.
 * @return bool True if required version is compatible or empty, false if not.
 */
function is_php_version_compatible( $required ) {
	return empty( $required ) || version_compare( PHP_VERSION, $required, '>=' );
}

/**
 * Checks if two numbers are nearly the same.
 *
 * This is similar to using `round()` but the precision is more fine-grained.
 *
 * @since 5.3.0
 *
 * @param int|float $expected  The expected value.
 * @param int|float $actual    The actual number.
 * @param int|float $precision Optional. The allowed variation. Default 1.
 * @return bool Whether the numbers match within the specified precision.
 */
function wp_fuzzy_number_match( $expected, $actual, $precision = 1 ) {
	return abs( (float) $expected - (float) $actual ) <= $precision;
}

/**
 * Creates and returns the markup for an admin notice.
 *
 * @since 6.4.0
 *
 * @param string $message The message.
 * @param array  $args {
 *     Optional. An array of arguments for the admin notice. Default empty array.
 *
 *     @type string   $type               Optional. The type of admin notice.
 *                                        For example, 'error', 'success', 'warning', 'info'.
 *                                        Default empty string.
 *     @type bool     $dismissible        Optional. Whether the admin notice is dismissible. Default false.
 *     @type string   $id                 Optional. The value of the admin notice's ID attribute. Default empty string.
 *     @type string[] $additional_classes Optional. A string array of class names. Default empty array.
 *     @type string[] $attributes         Optional. Additional attributes for the notice div. Default empty array.
 *     @type bool     $paragraph_wrap     Optional. Whether to wrap the message in paragraph tags. Default true.
 * }
 * @return string The markup for an admin notice.
 */
function wp_get_admin_notice( $message, $args = array() ) {
	$defaults = array(
		'type'               => '',
		'dismissible'        => false,
		'id'                 => '',
		'additional_classes' => array(),
		'attributes'         => array(),
		'paragraph_wrap'     => true,
	);

	$args = wp_parse_args( $args, $defaults );

	/**
	 * Filters the arguments for an admin notice.
	 *
	 * @since 6.4.0
	 *
	 * @param array  $args    The arguments for the admin notice.
	 * @param string $message The message for the admin notice.
	 */
	$args       = apply_filters( 'wp_admin_notice_args', $args, $message );
	$id         = '';
	$classes    = 'notice';
	$attributes = '';

	if ( is_string( $args['id'] ) ) {
		$trimmed_id = trim( $args['id'] );

		if ( '' !== $trimmed_id ) {
			$id = 'id="' . $trimmed_id . '" ';
		}
	}

	if ( is_string( $args['type'] ) ) {
		$type = trim( $args['type'] );

		if ( str_contains( $type, ' ' ) ) {
			_doing_it_wrong(
				__FUNCTION__,
				sprintf(
					/* translators: %s: The "type" key. */
					__( 'The %s key must be a string without spaces.' ),
					'<code>type</code>'
				),
				'6.4.0'
			);
		}

		if ( '' !== $type ) {
			$classes .= ' notice-' . $type;
		}
	}

	if ( true === $args['dismissible'] ) {
		$classes .= ' is-dismissible';
	}

	if ( is_array( $args['additional_classes'] ) && ! empty( $args['additional_classes'] ) ) {
		$classes .= ' ' . implode( ' ', $args['additional_classes'] );
	}

	if ( is_array( $args['attributes'] ) && ! empty( $args['attributes'] ) ) {
		$attributes = '';
		foreach ( $args['attributes'] as $attr => $val ) {
			if ( is_bool( $val ) ) {
				$attributes .= $val ? ' ' . $attr : '';
			} elseif ( is_int( $attr ) ) {
				$attributes .= ' ' . esc_attr( trim( $val ) );
			} elseif ( $val ) {
				$attributes .= ' ' . $attr . '="' . esc_attr( trim( $val ) ) . '"';
			}
		}
	}

	if ( false !== $args['paragraph_wrap'] ) {
		$message = "<p>$message</p>";
	}

	$markup = sprintf( '<div %1$sclass="%2$s"%3$s>%4$s</div>', $id, $classes, $attributes, $message );

	/**
	 * Filters the markup for an admin notice.
	 *
	 * @since 6.4.0
	 *
	 * @param string $markup  The HTML markup for the admin notice.
	 * @param string $message The message for the admin notice.
	 * @param array  $args    The arguments for the admin notice.
	 */
	return apply_filters( 'wp_admin_notice_markup', $markup, $message, $args );
}

/**
 * Outputs an admin notice.
 *
 * @since 6.4.0
 *
 * @param string $message The message to output.
 * @param array  $args {
 *     Optional. An array of arguments for the admin notice. Default empty array.
 *
 *     @type string   $type               Optional. The type of admin notice.
 *                                        For example, 'error', 'success', 'warning', 'info'.
 *                                        Default empty string.
 *     @type bool     $dismissible        Optional. Whether the admin notice is dismissible. Default false.
 *     @type string   $id                 Optional. The value of the admin notice's ID attribute. Default empty string.
 *     @type string[] $additional_classes Optional. A string array of class names. Default empty array.
 *     @type string[] $attributes         Optional. Additional attributes for the notice div. Default empty array.
 *     @type bool     $paragraph_wrap     Optional. Whether to wrap the message in paragraph tags. Default true.
 * }
 */
function wp_admin_notice( $message, $args = array() ) {
	/**
	 * Fires before an admin notice is output.
	 *
	 * @since 6.4.0
	 *
	 * @param string $message The message for the admin notice.
	 * @param array  $args    The arguments for the admin notice.
	 */
	do_action( 'wp_admin_notice', $message, $args );

	echo wp_kses_post( wp_get_admin_notice( $message, $args ) );
}