<?php
/**
 * Sensor: System
 *
 * System sensor class file.
 *
 * @since      4.6.0
 * @package    wsal
 * @subpackage sensors
 */

declare(strict_types=1);

namespace WSAL\WP_Sensors;

use WSAL\Controllers\Alert_Manager;

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

if ( ! class_exists( '\WSAL\WP_Sensors\WP_System_Sensor' ) ) {

	/**
	 * System Activity sensor.
	 *
	 * 6000 Events automatically pruned by system
	 * 6001 Option Anyone Can Register in WordPress settings changed
	 * 6002 New User Default Role changed
	 * 6003 WordPress Administrator Notification email changed
	 * 6004 WordPress was updated
	 * 6005 User changes the WordPress Permalinks
	 * 8009 User changed forum's role
	 * 8010 User changed option of a forum
	 * 8012 User changed time to disallow post editing
	 * 8013 User changed the forum setting posting throttle time
	 * 1006 User logged out all other sessions with the same username
	 * 6004 WordPress was updated
	 * 6008 Enabled/Disabled the option Discourage search engines from indexing this site
	 * 6009 Enabled/Disabled comments on all the website
	 * 6010 Enabled/Disabled the option Comment author must fill out name and email
	 * 6011 Enabled/Disabled the option Users must be logged in and registered to comment
	 * 6012 Enabled/Disabled the option to automatically close comments
	 * 6013 Changed the value of the option Automatically close comments
	 * 6014 Enabled/Disabled the option for comments to be manually approved
	 * 6015 Enabled/Disabled the option for an author to have previously approved comments for the comments to appear
	 * 6016 Changed the number of links that a comment must have to be held in the queue
	 * 6017 Modified the list of keywords for comments moderation
	 * 6018 Modified the list of keywords for comments blacklisting
	 * 6061 Email was sent
	 *
	 * @package    wsal
	 * @subpackage sensors
	 */
	class WP_System_Sensor {

		/**
		 * Inits the main hooks
		 *
		 * @return void
		 *
		 * @since 4.5.0
		 */
		public static function init() {
			add_action( 'wsal_prune', array( __CLASS__, 'event_prune_events' ), 10, 2 );
			add_action( 'admin_init', array( __CLASS__, 'event_admin_init' ) );
			add_action( 'automatic_updates_complete', array( __CLASS__, 'wp_update' ), 10, 1 );

			// whitelist options.
			add_action( 'allowed_options', array( __CLASS__, 'event_options' ), 10, 1 );

			// Update admin email alert.
			add_action( 'update_option_admin_email', array( __CLASS__, 'admin_email_changed' ), 10, 3 );

			// Customizable settings for the dynamic theme editing start.
			// Blogname change.
			add_action( 'customize_save_blogname', array( __CLASS__, 'site_blogname_change' ), 20, 1 );

			add_action( 'wp_mail_succeeded', array( __CLASS__, 'mail_was_sent' ) );
		}

		/**
		 * Alert: Admin email changed.
		 *
		 * @param mixed  $old_value - The old option value.
		 * @param mixed  $new_value - The new option value.
		 * @param string $option    - Option name.
		 *
		 * @since 4.5.0
		 */
		public static function admin_email_changed( $old_value, $new_value, $option ) {
			// Check if the option is not empty and is admin_email.
			if ( ! empty( $old_value ) && ! empty( $new_value )
			&& ! empty( $option ) && 'admin_email' === $option ) {
				if ( $old_value !== $new_value ) {
					Alert_Manager::trigger_event(
						6003,
						array(
							'OldEmail'      => $old_value,
							'NewEmail'      => $new_value,
							'CurrentUserID' => wp_get_current_user()->ID,
						)
					);
				}
			}
		}

		/**
		 * Method: Prune events function.
		 *
		 * @param int    $count The number of deleted events.
		 * @param string $query Query that selected events for deletion.
		 *
		 * @since 4.5.0
		 */
		public static function event_prune_events( $count, $query ) {
			Alert_Manager::trigger_event(
				6000,
				array(
					'EventCount' => $count,
					'PruneQuery' => $query,
				)
			);
		}

		/**
		 * Triggered when a user accesses the admin area.
		 *
		 * @since 4.5.0
		 */
		public static function event_admin_init() {
			// Filter global arrays for security.
			$post_array   = filter_input_array( INPUT_POST );
			$get_array    = filter_input_array( INPUT_GET );
			$server_array = filter_input_array( INPUT_SERVER );

			// Destroy all the session of the same user from user profile page.
			if ( isset( $post_array['action'] ) && ( 'destroy-sessions' === $post_array['action'] ) && isset( $post_array['user_id'] ) ) {
				Alert_Manager::trigger_event(
					1006,
					array(
						'TargetUserID' => $post_array['user_id'],
					)
				);
			}

			// Make sure user can actually modify target options.
			if ( ! current_user_can( 'manage_options' ) ) {
				return;
			}

			$actype = '';
			if ( ! empty( $server_array['SCRIPT_NAME'] ) ) {
				$actype = basename( $server_array['SCRIPT_NAME'], '.php' );
			}

			if ( isset( $post_array['action'] ) && 'toggle-auto-updates' === $post_array['action'] ) {
				$event_id = ( 'theme' === $post_array['type'] ) ? 5029 : 5028;

				if ( 'theme' === $post_array['type'] ) {
					$all_themes       = wp_get_themes();
					$our_theme        = $all_themes[ $post_array['asset'] ];
					$install_location = $our_theme->get_template_directory();
					$name             = $name->Name; // phpcs:ignore
				} elseif ( 'plugin' === $post_array['type'] ) {
					$all_plugins      = get_plugins();
					$our_plugin       = $all_plugins[ $post_array['asset'] ];
					$install_location = plugin_dir_path( WP_PLUGIN_DIR . '/' . $post_array['asset'] );
					$name             = $our_plugin['Name'];
				}

				Alert_Manager::trigger_event(
					$event_id,
					array(
						'install_directory' => $install_location,
						'name'              => $name,
						'EventType'         => ( 'enable' === $post_array['state'] ) ? 'enabled' : 'disabled',
					)
				);
			}

			$is_option_page      = 'options' === $actype;
			$is_network_settings = 'settings' === $actype;
			$is_permalink_page   = 'options-permalink' === $actype;

			// WordPress URL changed.
			if ( $is_option_page
			&& wp_verify_nonce( $post_array['_wpnonce'], 'general-options' )
			&& ! empty( $post_array['siteurl'] ) ) {
				$old_siteurl = get_option( 'siteurl' );
				$new_siteurl = isset( $post_array['siteurl'] ) ? $post_array['siteurl'] : '';
				if ( $old_siteurl !== $new_siteurl ) {
					Alert_Manager::trigger_event(
						6024,
						array(
							'old_url'       => $old_siteurl,
							'new_url'       => $new_siteurl,
							'CurrentUserID' => wp_get_current_user()->ID,
						)
					);
				}
			}

			// Site URL changed.
			if ( $is_option_page
			&& wp_verify_nonce( $post_array['_wpnonce'], 'general-options' )
			&& ! empty( $post_array['home'] ) ) {
				$old_url = get_option( 'home' );
				$new_url = isset( $post_array['home'] ) ? $post_array['home'] : '';
				if ( $old_url !== $new_url ) {
					Alert_Manager::trigger_event(
						6025,
						array(
							'old_url'       => $old_url,
							'new_url'       => $new_url,
							'CurrentUserID' => wp_get_current_user()->ID,
						)
					);
				}
			}

			if ( isset( $post_array['option_page'] ) && 'reading' === $post_array['option_page'] && isset( $post_array['show_on_front'] )
			&& wp_verify_nonce( $post_array['_wpnonce'], 'reading-options' ) ) {
				$old_homepage = ( 'posts' === get_site_option( 'show_on_front' ) ) ? __( 'latest posts', 'wp-security-audit-log' ) : __( 'static page', 'wp-security-audit-log' );
				$new_homepage = ( 'posts' === $post_array['show_on_front'] ) ? __( 'latest posts', 'wp-security-audit-log' ) : __( 'static page', 'wp-security-audit-log' );
				if ( $old_homepage !== $new_homepage ) {
					Alert_Manager::trigger_event(
						6035,
						array(
							'old_homepage' => $old_homepage,
							'new_homepage' => $new_homepage,
						)
					);
				}
			}

			if ( isset( $post_array['option_page'] ) && 'reading' === $post_array['option_page'] && isset( $post_array['page_on_front'] )
			&& wp_verify_nonce( $post_array['_wpnonce'], 'reading-options' ) ) {
				$old_frontpage = get_the_title( get_site_option( 'page_on_front' ) );
				$new_frontpage = get_the_title( $post_array['page_on_front'] );
				if ( $old_frontpage !== $new_frontpage ) {
					Alert_Manager::trigger_event(
						6036,
						array(
							'old_page' => $old_frontpage,
							'new_page' => $new_frontpage,
						)
					);
				}
			}

			if ( isset( $post_array['option_page'] ) && 'reading' === $post_array['option_page'] && isset( $post_array['page_for_posts'] )
			&& wp_verify_nonce( $post_array['_wpnonce'], 'reading-options' ) ) {
				$old_postspage = get_the_title( get_site_option( 'page_for_posts' ) );
				$new_postspage = get_the_title( $post_array['page_for_posts'] );
				if ( $old_postspage !== $new_postspage ) {
					Alert_Manager::trigger_event(
						6037,
						array(
							'old_page' => $old_postspage,
							'new_page' => $new_postspage,
						)
					);
				}
			}

			// Check timezone change.
			if ( $is_option_page && wp_verify_nonce( $post_array['_wpnonce'], 'general-options' ) && ! empty( $post_array['timezone_string'] ) ) {
				self::check_timezone_change( $post_array );
			}

			// Check date format change.
			if ( $is_option_page && wp_verify_nonce( $post_array['_wpnonce'], 'general-options' ) && ! empty( $post_array['date_format'] ) ) {
				$old_date_format = get_option( 'date_format' );
				$new_date_format = ( '\c\u\s\t\o\m' === $post_array['date_format'] ) ? $post_array['date_format_custom'] : $post_array['date_format'];
				if ( $old_date_format !== $new_date_format ) {
					Alert_Manager::trigger_event(
						6041,
						array(
							'old_date_format' => $old_date_format,
							'new_date_format' => $new_date_format,
							'CurrentUserID'   => wp_get_current_user()->ID,
						)
					);
				}
			}

			// Check time format change.
			if ( $is_option_page && wp_verify_nonce( $post_array['_wpnonce'], 'general-options' ) && ! empty( $post_array['time_format'] ) ) {
				$old_time_format = get_option( 'time_format' );
				$new_time_format = ( '\c\u\s\t\o\m' === $post_array['time_format'] ) ? $post_array['time_format_custom'] : $post_array['time_format'];
				if ( $old_time_format !== $new_time_format ) {
					Alert_Manager::trigger_event(
						6042,
						array(
							'old_time_format' => $old_time_format,
							'new_time_format' => $new_time_format,
							'CurrentUserID'   => wp_get_current_user()->ID,
						)
					);
				}
			}

			// Registration Option.
			if ( $is_option_page && wp_verify_nonce( $post_array['_wpnonce'], 'general-options' ) && ( get_option( 'users_can_register' ) xor isset( $post_array['users_can_register'] ) ) ) {
				$old = get_option( 'users_can_register' ) ? 'enabled' : 'disabled';
				$new = isset( $post_array['users_can_register'] ) ? 'enabled' : 'disabled';

				if ( $old !== $new ) {
					Alert_Manager::trigger_event(
						6001,
						array(
							'EventType'     => $new,
							'CurrentUserID' => wp_get_current_user()->ID,
						)
					);
				}
			}

			// Default Role option.
			if ( $is_option_page && wp_verify_nonce( $post_array['_wpnonce'], 'general-options' ) && ! empty( $post_array['default_role'] ) ) {
				$old = get_option( 'default_role' );
				$new = trim( $post_array['default_role'] );
				if ( $old !== $new ) {
					Alert_Manager::trigger_event(
						6002,
						array(
							'OldRole'       => $old,
							'NewRole'       => $new,
							'CurrentUserID' => wp_get_current_user()->ID,
						)
					);
				}
			}

			// Admin Email Option.
			if ( $is_option_page && wp_verify_nonce( $post_array['_wpnonce'], 'general-options' ) && ! empty( $post_array['admin_email'] ) ) {
				$old = get_option( 'admin_email' );
				$new = trim( $post_array['admin_email'] );
				if ( $old !== $new ) {
					Alert_Manager::trigger_event(
						6003,
						array(
							'OldEmail'      => $old,
							'NewEmail'      => $new,
							'CurrentUserID' => wp_get_current_user()->ID,
						)
					);
				}
			}

			// Admin Email of Network.
			if ( $is_network_settings && ! empty( $post_array['new_admin_email'] ) && wp_verify_nonce( $post_array['_wpnonce'], 'siteoptions' ) ) {
				$old = get_site_option( 'admin_email' );
				$new = trim( $post_array['new_admin_email'] );
				if ( $old !== $new ) {
					Alert_Manager::trigger_event(
						6003,
						array(
							'OldEmail'      => $old,
							'NewEmail'      => $new,
							'CurrentUserID' => wp_get_current_user()->ID,
						)
					);
				}
			}

			// Permalinks changed.
			if ( $is_permalink_page && ! empty( $post_array['permalink_structure'] )
			&& wp_verify_nonce( $post_array['_wpnonce'], 'update-permalink' ) ) {
				$old = get_option( 'permalink_structure' );
				$new = trim( $post_array['permalink_structure'] );
				if ( $old !== $new ) {
					Alert_Manager::trigger_event(
						6005,
						array(
							'OldPattern'    => $old,
							'NewPattern'    => $new,
							'CurrentUserID' => wp_get_current_user()->ID,
						)
					);
				}
			}

			// Core Update.
			if ( isset( $get_array['action'] ) && 'do-core-upgrade' === $get_array['action'] && isset( $post_array['version'] )
			&& wp_verify_nonce( $post_array['_wpnonce'], 'upgrade-core' ) ) {
				$old_version = get_bloginfo( 'version' );
				$new_version = $post_array['version'];
				if ( $old_version !== $new_version ) {
					Alert_Manager::trigger_event(
						6004,
						array(
							'OldVersion' => $old_version,
							'NewVersion' => $new_version,
						)
					);
				}
			}

			// Enable core updates.
			if ( isset( $get_array['action'] ) && 'core-major-auto-updates-settings' === $get_array['action'] && isset( $get_array['value'] )
			&& wp_verify_nonce( $get_array['_wpnonce'], 'core-major-auto-updates-nonce' ) ) {
				$status = ( 'enable' === $get_array['value'] ) ? esc_html__( 'automatically update to all new versions of WordPress', 'wp-security-audit-log' ) : esc_html__( 'automatically update maintenance and security releases only', 'wp-security-audit-log' );
				Alert_Manager::trigger_event(
					6044,
					array(
						'updates_status' => $status,
					)
				);
			}

			// Site Language changed.
			if ( $is_option_page
			&& wp_verify_nonce( $post_array['_wpnonce'], 'general-options' )
			&& isset( $post_array['WPLANG'] ) ) {
				// Is there a better way to turn the language into a "nice name"?
				require_once ABSPATH . 'wp-admin/includes/translation-install.php';
				$available_translations = wp_get_available_translations();

				// When English (United States) is selected, the WPLANG post entry is empty so lets account for this.
				$wplang_setting = get_option( 'WPLANG' );
				$previous_value = ( ! empty( $wplang_setting ) ) ? $wplang_setting : 'en-US';
				$new_value      = ( ! empty( $post_array['WPLANG'] ) ) ? $post_array['WPLANG'] : 'en-US';

				// Now lets turn these into a nice, native name - the same as shown to the user when choosing a language.
				$previous_value = ( isset( $available_translations[ $previous_value ] ) ) ? $available_translations[ $previous_value ]['native_name'] : 'English (United States)';
				$new_value      = ( isset( $available_translations[ $new_value ] ) ) ? $available_translations[ $new_value ]['native_name'] : 'English (United States)';

				if ( $previous_value !== $new_value ) {
					Alert_Manager::trigger_event(
						6045,
						array(
							'previous_value' => $previous_value,
							'new_value'      => $new_value,
						)
					);
				}
			}

			// Site title.
			if ( $is_option_page
			&& wp_verify_nonce( $post_array['_wpnonce'], 'general-options' )
			&& isset( $post_array['blogname'] ) ) {
				$previous_value = get_option( 'blogname' );
				$new_value      = ( ! empty( $post_array['blogname'] ) ) ? $post_array['blogname'] : '';

				if ( $previous_value !== $new_value ) {
					Alert_Manager::trigger_event(
						6059,
						array(
							'previous_value' => $previous_value,
							'new_value'      => $new_value,
						)
					);
				}
			}
		}

		/**
		 * WordPress auto core update.
		 *
		 * @param array $automatic - Automatic update array.
		 *
		 * @since 4.5.0
		 */
		public static function wp_update( $automatic ) {
			if ( isset( $automatic['core'][0] ) ) {
				$obj         = $automatic['core'][0];
				$old_version = get_bloginfo( 'version' );
				Alert_Manager::trigger_event(
					6004,
					array(
						'OldVersion' => $old_version,
						'NewVersion' => $obj->item->version . ' (auto update)',
					)
				);
			}
		}

		/**
		 * Events from 6008 to 6018.
		 *
		 * @param array $whitelist - White list options.
		 *
		 * @return array|null
		 *
		 * @since 4.5.0
		 */
		public static function event_options( $whitelist = null ) {
			// Filter global arrays for security.
			$post_array = filter_input_array( INPUT_POST );

			if ( isset( $post_array['option_page'] ) && 'reading' === $post_array['option_page'] ) {
				$old_status = (int) get_option( 'blog_public', 1 );
				$new_status = isset( $post_array['blog_public'] ) ? 0 : 1;

				if ( $old_status !== $new_status ) {
					Alert_Manager::trigger_event(
						6008,
						array( 'EventType' => ( 0 === $new_status ) ? 'enabled' : 'disabled' )
					);
				}
			}

			if ( isset( $post_array['option_page'] ) && 'discussion' === $post_array['option_page'] ) {
				$old_status = get_option( 'default_comment_status', 'closed' );
				$new_status = isset( $post_array['default_comment_status'] ) ? 'open' : 'closed';

				if ( $old_status !== $new_status ) {
					Alert_Manager::trigger_event(
						6009,
						array( 'EventType' => ( 'open' === $new_status ) ? 'enabled' : 'disabled' )
					);
				}

				$old_status = (int) get_option( 'require_name_email', 0 );
				$new_status = isset( $post_array['require_name_email'] ) ? 1 : 0;

				if ( $old_status !== $new_status ) {
					Alert_Manager::trigger_event(
						6010,
						array( 'EventType' => ( 1 === $new_status ) ? 'enabled' : 'disabled' )
					);
				}

				$old_status = (int) get_option( 'comment_registration', 0 );
				$new_status = isset( $post_array['comment_registration'] ) ? 1 : 0;

				if ( $old_status !== $new_status ) {
					Alert_Manager::trigger_event(
						6011,
						array( 'EventType' => ( 1 === $new_status ) ? 'enabled' : 'disabled' )
					);
				}

				$old_status = (int) get_option( 'close_comments_for_old_posts', 0 );
				$new_status = isset( $post_array['close_comments_for_old_posts'] ) ? 1 : 0;

				if ( $old_status !== $new_status ) {
					$value = isset( $post_array['close_comments_days_old'] ) ? $post_array['close_comments_days_old'] : 0;
					Alert_Manager::trigger_event(
						6012,
						array(
							'EventType' => ( 1 === $new_status ) ? 'enabled' : 'disabled',
							'Value'     => $value,
						)
					);
				}

				$old_value = get_option( 'close_comments_days_old', 0 );
				$new_value = isset( $post_array['close_comments_days_old'] ) ? $post_array['close_comments_days_old'] : 0;
				if ( $old_value !== $new_value ) {
					Alert_Manager::trigger_event(
						6013,
						array(
							'OldValue' => $old_value,
							'NewValue' => $new_value,
						)
					);
				}

				$old_status = (int) get_option( 'comment_moderation', 0 );
				$new_status = isset( $post_array['comment_moderation'] ) ? 1 : 0;

				if ( $old_status !== $new_status ) {
					Alert_Manager::trigger_event(
						6014,
						array( 'EventType' => ( 1 === $new_status ) ? 'enabled' : 'disabled' )
					);
				}

				// Comment_whitelist option was renamed to comment_previously_approved in WordPress 5.5.0.
				$comment_whitelist_option_name = version_compare( get_bloginfo( 'version' ), '5.5.0', '<' ) ? 'comment_whitelist' : 'comment_previously_approved';
				$old_status                    = (int) get_option( $comment_whitelist_option_name, 0 );
				$new_status                    = isset( $post_array[ $comment_whitelist_option_name ] ) ? 1 : 0;

				if ( $old_status !== $new_status ) {
					Alert_Manager::trigger_event(
						6015,
						array( 'EventType' => ( 1 === $new_status ) ? 'enabled' : 'disabled' )
					);
				}

				$old_value = get_option( 'comment_max_links', 0 );
				$new_value = isset( $post_array['comment_max_links'] ) ? $post_array['comment_max_links'] : 0;
				if ( $old_value !== $new_value ) {
					Alert_Manager::trigger_event(
						6016,
						array(
							'OldValue' => $old_value,
							'NewValue' => $new_value,
						)
					);
				}

				$old_value = get_option( 'moderation_keys', 0 );
				$new_value = isset( $post_array['moderation_keys'] ) ? $post_array['moderation_keys'] : 0;
				if ( $old_value !== $new_value ) {
					Alert_Manager::trigger_event( 6017, array() );
				}

				// Blacklist_keys option was renamed to disallowed_keys in WordPress 5.5.0.
				$blacklist_keys_option_name = version_compare( get_bloginfo( 'version' ), '5.5.0', '<' ) ? 'blacklist_keys' : 'disallowed_keys';
				$old_value                  = get_option( $blacklist_keys_option_name, 0 );
				$new_value                  = isset( $post_array[ $blacklist_keys_option_name ] ) ? $post_array[ $blacklist_keys_option_name ] : 0;
				if ( $old_value !== $new_value ) {
					Alert_Manager::trigger_event( 6018, array() );
				}
			}
			return $whitelist;
		}

		/**
		 * Site blogname change via customizable theme page
		 *
		 * @param \WP_Customize_Setting $customizable - The class with the customizable properties.
		 *
		 * @return void
		 *
		 * @since 4.5.0
		 */
		public static function site_blogname_change( $customizable ) {
			if ( isset( $_POST['customized'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Missing
				$post_values = json_decode( \sanitize_text_field( wp_unslash( $_POST['customized'] ) ), true ); // phpcs:ignore WordPress.Security.NonceVerification.Missing

				if ( $customizable->default !== $post_values['blogname'] ) {
					Alert_Manager::trigger_event(
						6059,
						array(
							'previous_value' => $customizable->default,
							'new_value'      => $post_values['blogname'],
						)
					);
				}
			}
		}

		/**
		 * Logs event when email is sent
		 *
		 * @param array $mail_data - Array of mail data.
		 *
		 * @return void
		 *
		 * @since 4.6.0
		 */
		public static function mail_was_sent( $mail_data ) {
			if ( \is_array( $mail_data ) && isset( $mail_data['to'] ) && isset( $mail_data['subject'] ) ) {
				Alert_Manager::trigger_event(
					6061,
					array(
						'Username'     => 'System',
						'EmailAddress' => $mail_data['to'],
						'EmailSubject' => $mail_data['subject'],
					)
				);
			}
		}

		/**
		 * Checks if the timezone settings have changed. Logs an events if it did.
		 *
		 * @param array $post_array Sanitized input array.
		 *
		 * @since 4.5.0
		 */
		private static function check_timezone_change( $post_array ) {
			$old_timezone_string = get_option( 'timezone_string' );
			$new_timezone_string = isset( $post_array['timezone_string'] ) ? $post_array['timezone_string'] : '';

			// Backup of the labels as we might change them below when dealing with UTC offset definitions.
			$old_timezone_label = $old_timezone_string;
			$new_timezone_label = $new_timezone_string;
			if ( strlen( $old_timezone_string ) === 0 ) {
				// The old timezone string can be empty if the time zone was configured using UTC offset selection
				// rather than using a country/city selection.
				$old_timezone_string = $old_timezone_label = wp_timezone_string(); // phpcs:ignore Squiz.PHP.DisallowMultipleAssignments.Found
				if ( 'UTC' === $old_timezone_string ) {
					$old_timezone_string = '+00:00';
				}

				// Adjusts label to show UTC offset consistently.
				$old_timezone_label = 'UTC' . $old_timezone_label;
			}

			// New timezone can be defined as UTC offset.

			// There is one UTC option that doesn't contain the offset, we need to tweak the value for further processing.
			if ( 'UTC' === $new_timezone_string ) {
				$new_timezone_string = 'UTC+0';
			}

			if ( preg_match( '/UTC([+\-][0-9\.]+)/', $new_timezone_string, $matches ) ) {
				$hours_decimal = floatval( $matches[1] );

				// The new timezone is also set using UTC offset, it needs to be converted to the same format used
				// by wp_timezone_string.
				$sign                = $hours_decimal < 0 ? '-' : '+';
				$abs_hours           = abs( $hours_decimal );
				$abs_mins            = abs( $hours_decimal * 60 % 60 );
				$new_timezone_string = sprintf( '%s%02d:%02d', $sign, floor( $abs_hours ), $abs_mins );

				// Adjusts label to show UTC offset consistently.
				$new_timezone_label = 'UTC' . $new_timezone_string;
			}

			if ( $old_timezone_string !== $new_timezone_string ) {
				Alert_Manager::trigger_event(
					6040,
					array(
						'old_timezone'  => $old_timezone_label,
						'new_timezone'  => $new_timezone_label,
						'CurrentUserID' => wp_get_current_user()->ID,
					)
				);
			}
		}
	}
}