Fixes eigen lockers bypassing TP protection (#74722)

## About The Pull Request
Fixes eigenlockers bypassing teleport protections.


![image](https://user-images.githubusercontent.com/41448081/231939450-42287185-48f4-4a3b-ac7a-38adc0600633.png)

Tested w/ one and multiple lockers, prevents entering or exiting from a
tp-prot eigenlocker

## Why It's Good For The Game
This came up in an away mission designed to be a "one-way-trip", the
only exit being at the very end of the away mission. However, people are
able to bypass this with eigenlockers, thanks to them performing no
teleportation checks, which I believe is an oversight.

## Changelog
🆑
fix: Eigenstasium lockers no longer bypass teleport protection
/🆑

---------

Co-authored-by: Mothblocks <35135081+Mothblocks@users.noreply.github.com>
Co-authored-by: san7890 <the@san7890.com>

code/__DEFINES/dcs/signals/signals_atom/signals_atom_main.dm

@@ -76,8 +76,10 @@
 #define COMSIG_ATOM_CREATEDBY_PROCESSING "atom_createdby_processing"
 ///when an atom is processed (mob/living/user, obj/item/I, list/atom/results)
 #define COMSIG_ATOM_PROCESSED "atom_processed"
-///called when teleporting into a protected turf: (channel, turf/origin)
-#define COMSIG_ATOM_INTERCEPT_TELEPORT "intercept_teleport"
+///called when teleporting into a possibly protected turf: (channel, turf/origin, turf/destination)
+#define COMSIG_ATOM_INTERCEPT_TELEPORTING "intercept_teleporting"
+///called after teleporting into a protected turf: (channel, turf/origin)
+#define COMSIG_ATOM_INTERCEPT_TELEPORTED "intercept_teleported"
 	#define COMPONENT_BLOCK_TELEPORT (1<<0)
 ///called when an atom is added to the hearers on get_hearers_in_view(): (list/processing_list, list/hearers)
 #define COMSIG_ATOM_HEARER_IN_VIEW "atom_hearer_in_view"

code/__DEFINES/dcs/signals/signals_atom/signals_atom_movable.dm

@@ -78,6 +78,8 @@
 #define COMSIG_MOVABLE_UPDATE_GLIDE_SIZE "movable_glide_size"
 ///Called when a movable is hit by a plunger in layer mode, from /obj/item/plunger/attack_atom()
 #define COMSIG_MOVABLE_CHANGE_DUCT_LAYER "movable_change_duct_layer"
+///Called before a movable is being teleported from `check_teleport_valid()`: (destination, channel)
+#define COMSIG_MOVABLE_TELEPORTING "movable_teleporting"
 ///Called when a movable is being teleported from `do_teleport()`: (destination, channel)
 #define COMSIG_MOVABLE_TELEPORTED "movable_teleported"
 ///Called after a movable is teleported from `do_teleport()`: ()

code/__DEFINES/movement.dm

@@ -109,6 +109,8 @@ GLOBAL_VAR_INIT(glide_size_multiplier, 1.0)
 #define TELEPORT_CHANNEL_MAGIC "magic"
 /// Cult teleportation, does whatever it wants (unless there's holiness)
 #define TELEPORT_CHANNEL_CULT "cult"
+/// Eigenstate teleportation, can do most things (that aren't in a teleport-prevented zone)
+#define TELEPORT_CHANNEL_EIGENSTATE "eigenstate"
 /// Anything else
 #define TELEPORT_CHANNEL_FREE "free"
 

code/controllers/subsystem/eigenstate.dm

@@ -101,7 +101,11 @@ SUBSYSTEM_DEF(eigenstates)
 	if(!eigen_target)
 		stack_trace("No eigen target set for the eigenstate component!")
 		return FALSE
+	if(check_teleport_valid(thing_to_send, eigen_target, TELEPORT_CHANNEL_EIGENSTATE))
 		thing_to_send.forceMove(get_turf(eigen_target))
+	else
+		object_sent_from.balloon_alert(thing_to_send, "nothing happens!")
+		return FALSE
 	//Create ONE set of sparks for ALL times in iteration
 	if(spark_time != world.time)
 		do_sparks(5, FALSE, eigen_target)

code/datums/helper_datums/teleport.dm

@@ -64,19 +64,8 @@
 	if(!destturf || !curturf || destturf.is_transition_turf())
 		return FALSE
 
-	var/area/from_area = get_area(curturf)
-	var/area/to_area = get_area(destturf)
 	if(!forced)
-		if(HAS_TRAIT(teleatom, TRAIT_NO_TELEPORT))
-			return FALSE
-
-		if((from_area.area_flags & NOTELEPORT) || (to_area.area_flags & NOTELEPORT))
-			return FALSE
-
-		if(SEND_SIGNAL(teleatom, COMSIG_MOVABLE_TELEPORTED, destination, channel) & COMPONENT_BLOCK_TELEPORT)
-			return FALSE
-
-		if(SEND_SIGNAL(destturf, COMSIG_ATOM_INTERCEPT_TELEPORT, channel, curturf, destturf) & COMPONENT_BLOCK_TELEPORT)
+		if(!check_teleport_valid(teleatom, destination, channel))
 			return FALSE
 
 	if(isobserver(teleatom))
@@ -202,3 +191,28 @@
 	var/list/turfs = get_teleport_turfs(center, precision)
 	if (length(turfs))
 		return pick(turfs)
+
+/// Validates that the teleport being attempted is valid or not
+/proc/check_teleport_valid(atom/teleported_atom, atom/destination, channel)
+	var/area/origin_area = get_area(teleported_atom)
+	var/turf/origin_turf = get_turf(teleported_atom)
+
+	var/area/destination_area = get_area(destination)
+	var/turf/destination_turf = get_turf(destination)
+
+	if(HAS_TRAIT(teleported_atom, TRAIT_NO_TELEPORT))
+		return FALSE
+
+	if((origin_area.area_flags & NOTELEPORT) || (destination_area.area_flags & NOTELEPORT))
+		return FALSE
+
+	if(SEND_SIGNAL(teleported_atom, COMSIG_MOVABLE_TELEPORTING, destination, channel) & COMPONENT_BLOCK_TELEPORT)
+		return FALSE
+
+	if(SEND_SIGNAL(destination_turf, COMSIG_ATOM_INTERCEPT_TELEPORTING, channel, origin_turf, destination_turf) & COMPONENT_BLOCK_TELEPORT)
+		return FALSE
+
+	SEND_SIGNAL(teleported_atom, COMSIG_MOVABLE_TELEPORTED, destination, channel)
+	SEND_SIGNAL(destination_turf, COMSIG_ATOM_INTERCEPT_TELEPORTED, channel, origin_turf, destination_turf)
+
+	return TRUE

code/game/objects/effects/blessing.dm

@@ -16,10 +16,10 @@
 		I.alpha = 64
 		I.appearance_flags = RESET_ALPHA
 		add_alt_appearance(/datum/atom_hud/alternate_appearance/basic/blessed_aware, "blessing", I)
-	RegisterSignal(loc, COMSIG_ATOM_INTERCEPT_TELEPORT, PROC_REF(block_cult_teleport))
+	RegisterSignal(loc, COMSIG_ATOM_INTERCEPT_TELEPORTING, PROC_REF(block_cult_teleport))
 
 /obj/effect/blessing/Destroy()
-	UnregisterSignal(loc, COMSIG_ATOM_INTERCEPT_TELEPORT)
+	UnregisterSignal(loc, COMSIG_ATOM_INTERCEPT_TELEPORTING)
 	return ..()
 
 /obj/effect/blessing/proc/block_cult_teleport(datum/source, channel, turf/origin, turf/destination)

code/modules/antagonists/heretic/status_effects/mark_effects.dm

@@ -144,13 +144,13 @@
 /datum/status_effect/eldritch/blade/on_apply()
 	. = ..()
 	RegisterSignal(owner, COMSIG_MOVABLE_PRE_THROW, PROC_REF(on_pre_throw))
-	RegisterSignal(owner, COMSIG_MOVABLE_TELEPORTED, PROC_REF(on_teleport))
+	RegisterSignal(owner, COMSIG_MOVABLE_TELEPORTING, PROC_REF(on_teleport))
 	RegisterSignal(owner, COMSIG_MOVABLE_MOVED, PROC_REF(on_move))
 
 /datum/status_effect/eldritch/blade/on_remove()
 	UnregisterSignal(owner, list(
 		COMSIG_MOVABLE_PRE_THROW,
-		COMSIG_MOVABLE_TELEPORTED,
+		COMSIG_MOVABLE_TELEPORTING,
 		COMSIG_MOVABLE_MOVED,
 	))