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code/__DEFINES/ai/ai.dm

@@ -2,8 +2,12 @@
 #define GET_TARGETING_STRATEGY(targeting_type) SSai_behaviors.targeting_strategies[targeting_type]
 #define HAS_AI_CONTROLLER_TYPE(thing, type) istype(thing?.ai_controller, type)
 
-#define AI_STATUS_ON 1
-#define AI_STATUS_OFF 2
+//AI controller flags
+//If you add a new status, be sure to add it to the ai_controllers subsystem's ai_controllers_by_status list.
+///The AI is currently active.
+#define AI_STATUS_ON "ai_on"
+///The AI is currently offline for any reason.
+#define AI_STATUS_OFF "ai_off"
 
 ///For JPS pathing, the maximum length of a path we'll try to generate. Should be modularized depending on what we're doing later on
 #define AI_MAX_PATH_LENGTH 30 // 30 is possibly overkill since by default we lose interest after 14 tiles of distance, but this gives wiggle room for weaving around obstacles

code/__DEFINES/mobs.dm

@@ -341,7 +341,6 @@
 #define AI_ON 1
 #define AI_IDLE 2
 #define AI_OFF 3
-#define AI_Z_OFF 4
 
 //The range at which a mob should wake up if you spawn into the z level near it
 #define MAX_SIMPLEMOB_WAKEUP_RANGE 5

code/__DEFINES/subsystems.dm

@@ -193,7 +193,6 @@
 // If the subsystem isn't listed here it's either DEFAULT or PROCESS (if it's a processing subsystem child)
 
 #define FIRE_PRIORITY_PING 10
-#define FIRE_PRIORITY_IDLE_NPC 10
 #define FIRE_PRIORITY_SERVER_MAINT 10
 #define FIRE_PRIORITY_RESEARCH 10
 #define FIRE_PRIORITY_VIS 10

code/_globalvars/lists/mobs.dm

@@ -59,7 +59,7 @@ GLOBAL_LIST_EMPTY(human_list) //all instances of /mob/living/carbon/human and su
 GLOBAL_LIST_EMPTY(ai_list)
 GLOBAL_LIST_EMPTY(pai_list)
 GLOBAL_LIST_EMPTY(available_ai_shells)
-GLOBAL_LIST_INIT(simple_animals, list(list(),list(),list(),list())) // One for each AI_* status define
+GLOBAL_LIST_INIT(simple_animals, list(list(),list(),list())) // One for each AI_* status define
 GLOBAL_LIST_EMPTY(spidermobs) //all sentient spider mobs
 GLOBAL_LIST_EMPTY(bots_list)
 GLOBAL_LIST_EMPTY(aiEyes)

code/controllers/subsystem/ai_controllers.dm

@@ -3,27 +3,32 @@ SUBSYSTEM_DEF(ai_controllers)
 	name = "AI Controller Ticker"
 	flags = SS_POST_FIRE_TIMING|SS_BACKGROUND
 	priority = FIRE_PRIORITY_NPC
-	runlevels = RUNLEVEL_GAME | RUNLEVEL_POSTGAME
 	init_order = INIT_ORDER_AI_CONTROLLERS
 	wait = 0.5 SECONDS //Plan every half second if required, not great not terrible.
+	runlevels = RUNLEVEL_GAME | RUNLEVEL_POSTGAME
 
 	///List of all ai_subtree singletons, key is the typepath while assigned value is a newly created instance of the typepath. See setup_subtrees()
-	var/list/ai_subtrees = list()
-	///List of all ai controllers currently running
-	var/list/active_ai_controllers = list()
+	var/list/datum/ai_planning_subtree/ai_subtrees = list()
+	///Assoc List of all AI statuses and all AI controllers with that status.
+	var/list/ai_controllers_by_status = list(
+		AI_STATUS_ON = list(),
+		AI_STATUS_OFF = list(),
+	)
+	///Assoc List of all AI controllers and the Z level they are on, which we check when someone enters/leaves a Z level to turn them on/off.
+	var/list/ai_controllers_by_zlevel = list()
 
 /datum/controller/subsystem/ai_controllers/Initialize()
 	setup_subtrees()
 	return SS_INIT_SUCCESS
 
-/datum/controller/subsystem/ai_controllers/proc/setup_subtrees()
-	ai_subtrees = list()
-	for(var/subtree_type in subtypesof(/datum/ai_planning_subtree))
-		var/datum/ai_planning_subtree/subtree = new subtree_type
-		ai_subtrees[subtree_type] = subtree
+/datum/controller/subsystem/ai_controllers/stat_entry(msg)
+	var/list/active_list = ai_controllers_by_status[AI_STATUS_ON]
+	var/list/inactive_list = ai_controllers_by_status[AI_STATUS_OFF]
+	msg = "Active AIs:[length(active_list)]|Inactive:[length(inactive_list)]"
+	return ..()
 
 /datum/controller/subsystem/ai_controllers/fire(resumed)
-	for(var/datum/ai_controller/ai_controller as anything in active_ai_controllers)
+	for(var/datum/ai_controller/ai_controller as anything in ai_controllers_by_status[AI_STATUS_ON])
 		if(!COOLDOWN_FINISHED(ai_controller, failed_planning_cooldown))
 			continue
 
@@ -32,3 +37,17 @@ SUBSYSTEM_DEF(ai_controllers)
 		ai_controller.SelectBehaviors(wait * 0.1)
 		if(!LAZYLEN(ai_controller.current_behaviors)) //Still no plan
 			COOLDOWN_START(ai_controller, failed_planning_cooldown, AI_FAILED_PLANNING_COOLDOWN)
+
+///Creates all instances of ai_subtrees and assigns them to the ai_subtrees list.
+/datum/controller/subsystem/ai_controllers/proc/setup_subtrees()
+	for(var/subtree_type in subtypesof(/datum/ai_planning_subtree))
+		var/datum/ai_planning_subtree/subtree = new subtree_type
+		ai_subtrees[subtree_type] = subtree
+
+///Called when the max Z level was changed, updating our coverage.
+/datum/controller/subsystem/ai_controllers/proc/on_max_z_changed()
+	if (!islist(ai_controllers_by_zlevel))
+		ai_controllers_by_zlevel = new /list(world.maxz,0)
+	while (SSai_controllers.ai_controllers_by_zlevel.len < world.maxz)
+		SSai_controllers.ai_controllers_by_zlevel.len++
+		SSai_controllers.ai_controllers_by_zlevel[ai_controllers_by_zlevel.len] = list()

code/datums/ai/_ai_controller.dm

@@ -68,7 +68,6 @@ multiple modular subtrees with behaviors
 		PossessPawn(new_pawn)
 
 /datum/ai_controller/Destroy(force)
-	set_ai_status(AI_STATUS_OFF)
 	UnpossessPawn(FALSE)
 	set_movement_target(type, null)
 	if(ai_movement.moving_controllers[src])
@@ -116,9 +115,14 @@ multiple modular subtrees with behaviors
 	pawn = new_pawn
 	pawn.ai_controller = src
 
+	var/turf/pawn_turf = get_turf(pawn)
+	if(pawn_turf)
+		SSai_controllers.ai_controllers_by_zlevel[pawn_turf.z] += src
+
 	SEND_SIGNAL(src, COMSIG_AI_CONTROLLER_POSSESSED_PAWN)
 
 	reset_ai_status()
+	RegisterSignal(pawn, COMSIG_MOVABLE_Z_CHANGED, PROC_REF(on_changed_z_level))
 	RegisterSignal(pawn, COMSIG_MOB_STATCHANGE, PROC_REF(on_stat_changed))
 	RegisterSignal(pawn, COMSIG_MOB_LOGIN, PROC_REF(on_sentience_gained))
 	RegisterSignal(pawn, COMSIG_QDELETING, PROC_REF(on_pawn_qdeleted))
@@ -127,25 +131,53 @@ multiple modular subtrees with behaviors
 /datum/ai_controller/proc/reset_ai_status()
 	set_ai_status(get_expected_ai_status())
 
-/// Returns what the AI status should be based on current conditions.
+/**
+ * Gets the AI status we expect the AI controller to be on at this current moment.
+ * Returns AI_STATUS_OFF if it's inhabited by a Client and shouldn't be, if it's dead and cannot act while dead, or is on a z level without clients.
+ * Returns AI_STATUS_ON otherwise.
+ */
 /datum/ai_controller/proc/get_expected_ai_status()
-	var/final_status = AI_STATUS_ON
-
 	if (!ismob(pawn))
-		return final_status
+		return AI_STATUS_ON
 
 	var/mob/living/mob_pawn = pawn
-
 	if(!continue_processing_when_client && mob_pawn.client)
-		final_status = AI_STATUS_OFF
-
-	if(ai_traits & CAN_ACT_WHILE_DEAD)
-		return final_status
+		return AI_STATUS_OFF
 
 	if(mob_pawn.stat == DEAD)
-		final_status = AI_STATUS_OFF
+		if(ai_traits & CAN_ACT_WHILE_DEAD)
+			return AI_STATUS_ON
+		return AI_STATUS_OFF
+
+	var/turf/pawn_turf = get_turf(mob_pawn)
+#ifdef TESTING
+	if(!pawn_turf)
+		CRASH("AI controller [src] controlling pawn ([pawn]) is not on a turf.")
+#endif
+	if(!length(SSmobs.clients_by_zlevel[pawn_turf.z]))
+		return AI_STATUS_OFF
+	return AI_STATUS_ON
+
+/datum/ai_controller/proc/get_current_turf()
+	var/mob/living/mob_pawn = pawn
+	var/turf/pawn_turf = get_turf(mob_pawn)
+	to_chat(world, "[pawn_turf]")
 
-	return final_status
+///Called when the AI controller pawn changes z levels, we check if there's any clients on the new one and wake up the AI if there is.
+/datum/ai_controller/proc/on_changed_z_level(atom/source, turf/old_turf, turf/new_turf, same_z_layer, notify_contents)
+	SIGNAL_HANDLER
+	var/mob/mob_pawn = pawn
+	if((mob_pawn?.client && !continue_processing_when_client))
+		return
+	if(old_turf)
+		SSai_controllers.ai_controllers_by_zlevel[old_turf.z] -= src
+	if(new_turf)
+		SSai_controllers.ai_controllers_by_zlevel[new_turf.z] += src
+		var/new_level_clients = SSmobs.clients_by_zlevel[new_turf.z].len
+		if(new_level_clients)
+			set_ai_status(AI_STATUS_ON)
+		else
+			set_ai_status(AI_STATUS_OFF)
 
 ///Abstract proc for initializing the pawn to the new controller
 /datum/ai_controller/proc/TryPossessPawn(atom/new_pawn)
@@ -156,9 +188,15 @@ multiple modular subtrees with behaviors
 	if(isnull(pawn))
 		return // instantiated without an applicable pawn, fine
 
-	UnregisterSignal(pawn, list(COMSIG_MOB_LOGIN, COMSIG_MOB_LOGOUT, COMSIG_MOB_STATCHANGE, COMSIG_QDELETING))
+	set_ai_status(AI_STATUS_OFF)
+	UnregisterSignal(pawn, list(COMSIG_MOVABLE_Z_CHANGED, COMSIG_MOB_LOGIN, COMSIG_MOB_LOGOUT, COMSIG_MOB_STATCHANGE, COMSIG_QDELETING))
 	if(ai_movement.moving_controllers[src])
 		ai_movement.stop_moving_towards(src)
+	var/turf/pawn_turf = get_turf(pawn)
+	if(pawn_turf)
+		SSai_controllers.ai_controllers_by_zlevel[pawn_turf.z] -= src
+	if(ai_status)
+		SSai_controllers.ai_controllers_by_status[ai_status] -= src
 	pawn.ai_controller = null
 	pawn = null
 	if(destroy)
@@ -269,15 +307,17 @@ multiple modular subtrees with behaviors
 /datum/ai_controller/proc/set_ai_status(new_ai_status)
 	if(ai_status == new_ai_status)
 		return FALSE //no change
-
+
+	//remove old status, if we've got one
+	if(ai_status)
+		SSai_controllers.ai_controllers_by_status[ai_status] -= src
 	ai_status = new_ai_status
+	SSai_controllers.ai_controllers_by_status[new_ai_status] += src
 	switch(ai_status)
 		if(AI_STATUS_ON)
-			SSai_controllers.active_ai_controllers += src
 			START_PROCESSING(SSai_behaviors, src)
 		if(AI_STATUS_OFF)
 			STOP_PROCESSING(SSai_behaviors, src)
-			SSai_controllers.active_ai_controllers -= src
 			CancelActions()
 
 /datum/ai_controller/proc/PauseAi(time)

code/game/world.dm

@@ -448,7 +448,7 @@ GLOBAL_VAR(restart_counter)
 /world/proc/incrementMaxZ()
 	maxz++
 	SSmobs.MaxZChanged()
-	SSidlenpcpool.MaxZChanged()
+	SSai_controllers.on_max_z_changed()
 
 /world/proc/change_fps(new_value = 20)
 	if(new_value <= 0)

code/modules/clothing/shoes/cowboy.dm

@@ -4,8 +4,8 @@
 	icon_state = "cowboy_brown"
 	armor_type = /datum/armor/shoes_cowboy
 	custom_price = PAYCHECK_CREW
-	var/max_occupants = 4
 	can_be_tied = FALSE
+	var/max_occupants = 4
 	/// Do these boots have spur sounds?
 	var/has_spurs = FALSE
 	/// The jingle jangle jingle of our spurs

code/modules/mob/dead/dead.dm

@@ -90,16 +90,20 @@ INITIALIZE_IMMEDIATE(/mob/dead)
 
 #undef SERVER_HOPPER_TRAIT
 
-/mob/dead/proc/update_z(new_z) // 1+ to register, null to unregister
-	if (registered_z != new_z)
-		if (registered_z)
-			SSmobs.dead_players_by_zlevel[registered_z] -= src
-		if (client)
-			if (new_z)
-				SSmobs.dead_players_by_zlevel[new_z] += src
-			registered_z = new_z
-		else
-			registered_z = null
+/**
+ * updates the Z level for dead players
+ * If they don't have a new z, we'll keep the old one, preventing bugs from ghosting and re-entering, among others
+ */
+/mob/dead/proc/update_z(new_z)
+	if(registered_z == new_z)
+		return
+	if(registered_z)
+		SSmobs.dead_players_by_zlevel[registered_z] -= src
+	if(isnull(client))
+		registered_z = null
+		return
+	registered_z = new_z
+	SSmobs.dead_players_by_zlevel[new_z] += src
 
 /mob/dead/Login()
 	. = ..()

code/modules/mob/dead/observer/login.dm

@@ -14,10 +14,6 @@
 		preferred_form = client.prefs.read_preference(/datum/preference/choiced/ghost_form)
 		ghost_orbit = client.prefs.read_preference(/datum/preference/choiced/ghost_orbit)
 
-	var/turf/T = get_turf(src)
-	if (isturf(T))
-		update_z(T.z)
-
 	update_icon(ALL, preferred_form)
 	updateghostimages()
 	client.set_right_click_menu_mode(FALSE)

code/modules/mob/dead/observer/logout.dm

@@ -1,5 +1,4 @@
 /mob/dead/observer/Logout()
-	update_z(null)
 	if (client)
 		client.images -= (GLOB.ghost_images_default+GLOB.ghost_images_simple)