updates dmapi from dmapi 5.1.0 to dmapi 5.2.1 (based off tgstation/tgstation#51100 ) (#12364)

code/datums/tgs_event_handler.dm

@@ -1,3 +1,6 @@
+/datum/tgs_event_handler/impl
+	var/datum/timedevent/reattach_timer
+
 /datum/tgs_event_handler/impl/HandleEvent(event_code, ...)
 	switch(event_code)
 		if(TGS_EVENT_REBOOT_MODE_CHANGE)
@@ -18,3 +21,19 @@
 		if(TGS_EVENT_DEPLOYMENT_COMPLETE)
 			message_admins("TGS: Deployment complete!")
 			to_chat(world, "<span class='boldannounce'>Server updated, changes will be applied on the next round...</span>")
+		if(TGS_EVENT_WATCHDOG_DETACH)
+			message_admins("TGS restarting...")
+			reattach_timer = addtimer(CALLBACK(src, .proc/LateOnReattach), 1 MINUTES)
+		if(TGS_EVENT_WATCHDOG_REATTACH)
+			var/datum/tgs_version/old_version = world.TgsVersion()
+			var/datum/tgs_version/new_version = args[2]
+			if(!old_version.Equals(new_version))
+				to_chat(world, "<span class='boldannounce'>TGS updated to v[old_version.deprefixed_parameter]</span>")
+			else
+				message_admins("TGS: Back online")
+			if(reattach_timer)
+				deltimer(reattach_timer)
+				reattach_timer = null
+
+/datum/tgs_event_handler/impl/proc/LateOnReattach()
+	message_admins("Warning: TGS hasn't notified us of it coming back for a full minute! Is there a problem?")