[MIRROR] Fixes cult softlock situations with the sacrifice objective. [MDB IGNORE] (#9824)

* Fixes cult softlock situations with the sacrifice objective. (#62983)

* Fixes cult softlock situations with the sacrifice objective.

Co-authored-by: Ghom <42542238+Ghommie@users.noreply.github.com>

code/__DEFINES/dcs/signals/signals_mind.dm

@@ -1,4 +1,6 @@
-// Antagonist signals
+///from mind/transfer_to. Sent after the mind has been transferred: (mob/previous_body)
+#define COMSIG_MIND_TRANSFERRED "mind_transferred"
+
 /// Called on the mind when an antagonist is being gained, after the antagonist list has updated (datum/antagonist/antagonist)
 #define COMSIG_ANTAGONIST_GAINED "antagonist_gained"
 

code/__DEFINES/dcs/signals/signals_mob/signals_mob_main.dm

@@ -32,6 +32,9 @@
 /// From base of /client/Move()
 #define COMSIG_MOB_CLIENT_MOVED "mob_client_moved"
 
+///from mind/transfer_to. Sent to the receiving mob.
+#define COMSIG_MOB_MIND_TRANSFERRED_INTO "mob_mind_transferred_into"
+
 ///from base of obj/allowed(mob/M): (/obj) returns bool, if TRUE the mob has id access to the obj
 #define COMSIG_MOB_ALLOWED "mob_allowed"
 ///from base of mob/anti_magic_check(): (mob/user, magic, holy, tinfoil, chargecost, self, protection_sources)

code/datums/mind.dm

@@ -185,6 +185,8 @@
 		LAZYCLEARLIST(new_character.client.recent_examines)
 		new_character.client.init_verbs() // re-initialize character specific verbs
 	current.update_atom_languages()
+	SEND_SIGNAL(src, COMSIG_MIND_TRANSFERRED, old_current)
+	SEND_SIGNAL(current, COMSIG_MOB_MIND_TRANSFERRED_INTO)
 
 //I cannot trust you fucks to do this properly
 /datum/mind/proc/set_original_character(new_original_character)

code/modules/antagonists/cult/cult.dm

@@ -326,7 +326,31 @@
 	reshape.Crop(-5,-3,26,30)
 	sac_objective.sac_image = reshape
 
+/datum/team/cult/proc/setup_objectives()
+	var/datum/objective/sacrifice/sacrifice_objective = new
+	sacrifice_objective.team = src
+	sacrifice_objective.find_target()
+	objectives += sacrifice_objective
+
+	var/datum/objective/eldergod/summon_objective = new
+	summon_objective.team = src
+	objectives += summon_objective
+
+/datum/objective/sacrifice
+	var/sacced = FALSE
+	var/sac_image
+
+/// Unregister signals from the old target so it doesn't cause issues when sacrificed of when a new target is found.
+/datum/objective/sacrifice/proc/clear_sacrifice()
+	if(!target)
+		return
+	UnregisterSignal(target, COMSIG_MIND_TRANSFERRED)
+	if(target.current)
+		UnregisterSignal(target.current, list(COMSIG_PARENT_QDELETING, COMSIG_MOB_MIND_TRANSFERRED_INTO))
+	target = null
+
 /datum/objective/sacrifice/find_target(dupe_search_range)
+	clear_sacrifice()
 	if(!istype(team, /datum/team/cult))
 		return
 	var/datum/team/cult/cult = team
@@ -343,27 +367,47 @@
 	if(LAZYLEN(target_candidates))
 		target = pick(target_candidates)
 		update_explanation_text()
+		// Register a bunch of signals to both the target mind and its body
+		// to stop cult from softlocking everytime the target is deleted before being actually sacrificed.
+		RegisterSignal(target, COMSIG_MIND_TRANSFERRED, .proc/on_mind_transfer)
+		RegisterSignal(target.current, COMSIG_PARENT_QDELETING, .proc/on_target_body_del)
+		RegisterSignal(target.current, COMSIG_MOB_MIND_TRANSFERRED_INTO, .proc/on_possible_mindswap)
 	else
 		message_admins("Cult Sacrifice: Could not find unconvertible or convertible target. WELP!")
-	cult.make_image(src)
+		sacced = TRUE // Prevents another hypothetical softlock. This basically means every PC is a cultist.
+	if(!sacced)
+		cult.make_image(src)
 	for(var/datum/mind/mind in cult.members)
 		if(mind.current)
 			mind.current.clear_alert("bloodsense")
 			mind.current.throw_alert("bloodsense", /atom/movable/screen/alert/bloodsense)
 
-/datum/team/cult/proc/setup_objectives()
-	var/datum/objective/sacrifice/sacrifice_objective = new
-	sacrifice_objective.team = src
-	sacrifice_objective.find_target()
-	objectives += sacrifice_objective
+/datum/objective/sacrifice/proc/on_target_body_del()
+	SIGNAL_HANDLER
+	INVOKE_ASYNC(src, .proc/find_target)
 
-	var/datum/objective/eldergod/summon_objective = new
-	summon_objective.team = src
-	objectives += summon_objective
+/datum/objective/sacrifice/proc/on_mind_transfer(datum/source, mob/previous_body)
+	SIGNAL_HANDLER
+	//If, for some reason, the mind was transferred to a ghost (better safe than sorry), find a new target.
+	if(!isliving(target.current))
+		INVOKE_ASYNC(src, .proc/find_target)
+		return
+	UnregisterSignal(previous_body, list(COMSIG_PARENT_QDELETING, COMSIG_MOB_MIND_TRANSFERRED_INTO))
+	RegisterSignal(target.current, COMSIG_PARENT_QDELETING, .proc/on_target_body_del)
+	RegisterSignal(target.current, COMSIG_MOB_MIND_TRANSFERRED_INTO, .proc/on_possible_mindswap)
 
-/datum/objective/sacrifice
-	var/sacced = FALSE
-	var/sac_image
+/datum/objective/sacrifice/proc/on_possible_mindswap(mob/source)
+	SIGNAL_HANDLER
+	UnregisterSignal(target.current, list(COMSIG_PARENT_QDELETING, COMSIG_MOB_MIND_TRANSFERRED_INTO))
+	//we check if the mind is bodyless only after mindswap shenanigeans to avoid issues.
+	addtimer(CALLBACK(src, .proc/do_we_have_a_body), 0 SECONDS)
+
+/datum/objective/sacrifice/proc/do_we_have_a_body()
+	if(!target.current) //The player was ghosted and the mind isn't probably going to be transferred to another mob at this point.
+		find_target()
+		return
+	RegisterSignal(target.current, COMSIG_PARENT_QDELETING, .proc/on_target_body_del)
+	RegisterSignal(target.current, COMSIG_MOB_MIND_TRANSFERRED_INTO, .proc/on_possible_mindswap)
 
 /datum/objective/sacrifice/check_completion()
 	return sacced || completed

code/modules/antagonists/cult/runes.dm

@@ -317,6 +317,7 @@ structure_check() searches for nearby cultist structures required for the invoca
 		for(var/datum/objective/sacrifice/sac_objective in C.cult_team.objectives)
 			if(sac_objective.target == sacrificial.mind)
 				sac_objective.sacced = TRUE
+				sac_objective.clear_sacrifice()
 				sac_objective.update_explanation_text()
 				big_sac = TRUE
 	else

tgstation.dme

@@ -175,7 +175,6 @@
 #include "code\__DEFINES\dcs\signals\signals_action.dm"
 #include "code\__DEFINES\dcs\signals\signals_admin.dm"
 #include "code\__DEFINES\dcs\signals\signals_adventure.dm"
-#include "code\__DEFINES\dcs\signals\signals_antagonist.dm"
 #include "code\__DEFINES\dcs\signals\signals_area.dm"
 #include "code\__DEFINES\dcs\signals\signals_bot.dm"
 #include "code\__DEFINES\dcs\signals\signals_circuit.dm"
@@ -191,6 +190,7 @@
 #include "code\__DEFINES\dcs\signals\signals_hydroponic.dm"
 #include "code\__DEFINES\dcs\signals\signals_janitor.dm"
 #include "code\__DEFINES\dcs\signals\signals_light_eater.dm"
+#include "code\__DEFINES\dcs\signals\signals_mind.dm"
 #include "code\__DEFINES\dcs\signals\signals_mood.dm"
 #include "code\__DEFINES\dcs\signals\signals_movetype.dm"
 #include "code\__DEFINES\dcs\signals\signals_music.dm"