ashed version for future comparison.
 *
 * @since 4.9.6
 *
 * @param int $request_id Request ID.
 * @return string Confirmation key.
 */
function wp_generate_user_request_key( $request_id ) {
	global $wp_hasher;

	// Generate something random for a confirmation key.
	$key = wp_generate_password( 20, false );

	// Return the key, hashed.
	if ( empty( $wp_hasher ) ) {
		require_once ABSPATH . WPINC . '/class-phpass.php';
		$wp_hasher = new PasswordHash( 8, true );
	}

	wp_update_post(
		array(
			'ID'            => $request_id,
			'post_status'   => 'request-pending',
			'post_password' => $wp_hasher->HashPassword( $key ),
		)
	);

	return $key;
}

/**
 * Validates a user request by comparing the key with the request's key.
 *
 * @since 4.9.6
 *
 * @param string $request_id ID of the request being confirmed.
 * @param string $key        Provided key to validate.
 * @return true|WP_Error True on success, WP_Error on failure.
 */
function wp_validate_user_request_key( $request_id, $key ) {
	global $wp_hasher;

	$request_id       = absint( $request_id );
	$request          = wp_get_user_request( $request_id );
	$saved_key        = $request->confirm_key;
	$key_request_time = $request->modified_timestamp;

	if ( ! $request || ! $saved_key || ! $key_request_time ) {
		return new WP_Error( 'invalid_request', __( 'Invalid personal data request.' ) );
	}

	if ( ! in_array( $request->status, array( 'request-pending', 'request-failed' ), true ) ) {
		return new WP_Error( 'expired_request', __( 'This personal data request has expired.' ) );
	}

	if ( empty( $key ) ) {
		return new WP_Error( 'missing_key', __( 'The confirmation key is missing from this personal data request.' ) );
	}

	if ( empty( $wp_hasher ) ) {
		require_once ABSPATH . WPINC . '/class-phpass.php';
		$wp_hasher = new PasswordHash( 8, true );
	}

	/**
	 * Filters the expiration time of confirm keys.
	 *
	 * @since 4.9.6
	 *
	 * @param int $expiration The expiration time in seconds.
	 */
	$expiration_duration = (int) apply_filters( 'user_request_key_expiration', DAY_IN_SECONDS );
	$expiration_time     = $key_request_time + $expiration_duration;

	if ( ! $wp_hasher->CheckPassword( $key, $saved_key ) ) {
		return new WP_Error( 'invalid_key', __( 'The confirmation key is invalid for this personal data request.' ) );
	}

	if ( ! $expiration_time || time() > $expiration_time ) {
		return new WP_Error( 'expired_key', __( 'The confirmation key has expired for this personal data request.' ) );
	}

	return true;
}

/**
 * Returns the user request object for the specified request ID.
 *
 * @since 4.9.6
 *
 * @param int $request_id The ID of the user request.
 * @return WP_User_Request|false
 */
function wp_get_user_request( $request_id ) {
	$request_id = absint( $request_id );
	$post       = get_post( $request_id );

	if ( ! $post || 'user_request' !== $post->post_type ) {
		return false;
	}

	return new WP_User_Request( $post );
}

/**
 * Checks if Application Passwords is supported.
 *
 * Application Passwords is supported only by sites using SSL or local environments
 * but may be made available using the {@see 'wp_is_application_passwords_available'} filter.
 *
 * @since 5.9.0
 *
 * @return bool
 */
function wp_is_application_passwords_supported() {
	return is_ssl() || 'local' === wp_get_environment_type();
}

/**
 * Checks if Application Passwords is globally available.
 *
 * By default, Application Passwords is available to all sites using SSL or to local environments.
 * Use the {@see 'wp_is_application_passwords_available'} filter to adjust its availability.
 *
 * @since 5.6.0
 *
 * @return bool
 */
function wp_is_application_passwords_available() {
	/**
	 * Filters whether Application Passwords is available.
	 *
	 * @since 5.6.0
	 *
	 * @param bool $available True if available, false otherwise.
	 */
	return apply_filters( 'wp_is_application_passwords_available', wp_is_application_passwords_supported() );
}

/**
 * Checks if Application Passwords is available for a specific user.
 *
 * By default all users can use Application Passwords. Use {@see 'wp_is_application_passwords_available_for_user'}
 * to restrict availability to certain users.
 *
 * @since 5.6.0
 *
 * @param int|WP_User $user The user to check.
 * @return bool
 */
function wp_is_application_passwords_available_for_user( $user ) {
	if ( ! wp_is_application_passwords_available() ) {
		return false;
	}

	if ( ! is_object( $user ) ) {
		$user = get_userdata( $user );
	}

	if ( ! $user || ! $user->exists() ) {
		return false;
	}

	/**
	 * Filters whether Application Passwords is available for a specific user.
	 *
	 * @since 5.6.0
	 *
	 * @param bool    $available True if available, false otherwise.
	 * @param WP_User $user      The user to check.
	 */
	return apply_filters( 'wp_is_application_passwords_available_for_user', true, $user );
}

/**
 * Registers the user meta property for persisted preferences.
 *
 * This property is used to store user preferences across page reloads and is
 * currently used by the block editor for preferences like 'fullscreenMode' and
 * 'fixedToolbar'.
 *
 * @since 6.1.0
 * @access private
 *
 * @global wpdb $wpdb WordPress database abstraction object.
 */
function wp_register_persisted_preferences_meta() {
	/*
	 * Create a meta key that incorporates the blog prefix so that each site
	 * on a multisite can have distinct user preferences.
	 */
	global $wpdb;
	$meta_key = $wpdb->get_blog_prefix() . 'persisted_preferences';

	register_meta(
		'user',
		$meta_key,
		array(
			'type'         => 'object',
			'single'       => true,
			'show_in_rest' => array(
				'name'   => 'persisted_preferences',
				'type'   => 'object',
				'schema' => array(
					'type'                 => 'object',
					'context'              => array( 'edit' ),
					'properties'           => array(
						'_modified' => array(
							'description' => __( 'The date and time the preferences were updated.' ),
							'type'        => 'string',
							'format'      => 'date-time',
							'readonly'    => false,
						),
					),
					'additionalProperties' => true,
				),
			),
		)
	);
}

/**
 * Sets the last changed time for the 'users' cache group.
 *
 * @since 6.3.0
 */
function wp_cache_set_users_last_changed() {
	wp_cache_set_last_changed( 'users' );
}

/**
 * Checks if password reset is allowed for a specific user.
 *
 * @since 6.3.0
 *
 * @param int|WP_User $user The user to check.
 * @return bool|WP_Error True if allowed, false or WP_Error otherwise.
 */
function wp_is_password_reset_allowed_for_user( $user ) {
	if ( ! is_object( $user ) ) {
		$user = get_userdata( $user );
	}

	if ( ! $user || ! $user->exists() ) {
		return false;
	}
	$allow = true;
	if ( is_multisite() && is_user_spammy( $user ) ) {
		$allow = false;
	}

	/**
	 * Filters whether to allow a password to be reset.
	 *
	 * @since 2.7.0
	 *
	 * @param bool $allow   Whether to allow the password to be reset. Default true.
	 * @param int  $user_id The ID of the user attempting to reset a password.
	 */
	return apply_filters( 'allow_password_reset', $allow, $user->ID );
}