[no gpb] fixes EVERYTHING wrong with golf carts (#93669)

## About The Pull Request
Fixes #93589, fixes #93594, fixes (probably) #93663 by BANNING mobs that
have things buckled on them from getting on. also if you try to buckle
to something that is already in the cart you CANT do that anymore

## Why It's Good For The Game
It fixes golf cart bugs which are NOT good.. :(

## Changelog

🆑
fix: fixes permanent soul binding between golf carts and riders
/🆑

code/modules/vehicles/cars/golfcart/golfcart.dm

@@ -151,6 +151,8 @@
 	if(!isliving(bumped_atom))
 		return
 	var/mob/living/mob = bumped_atom
+	if (mob in child.buckled_mobs)
+		return
 	mob.throw_at(get_edge_target_turf(mob, dir), 2, 3)
 	RegisterSignal(mob, COMSIG_MOVABLE_THROW_LANDED, PROC_REF(thrown_mob_landed))
 	mob.visible_message(
@@ -199,7 +201,8 @@
 	if (!is_hotrod())
 		return
 	for(var/mob/living/future_pancake in loc)
-		run_over(future_pancake)
+		if (!(future_pancake in child.buckled_mobs))
+			run_over(future_pancake)
 
 /obj/vehicle/ridden/golfcart/mouse_drop_receive(atom/dropped, mob/user, params)
 	if (child.can_load(dropped))

code/modules/vehicles/cars/golfcart/golfcart_rear.dm

@@ -171,8 +171,26 @@
 
 /obj/golfcart_rear/mouse_drop_receive(atom/dropped, mob/user, params)
 	if (!can_load(dropped))
+		if (!isliving(dropped) || (has_buckled_mobs() && buckled_mobs.len >= max_buckled_mobs))
+			balloon_alert_to_viewers("blocked!")
+			return
+		//Allow either 2 standing mobs or 1 lying down mob
+		//If a mob is already lying down it's obviously blocked.
 		if (has_buckled_mobs())
-			balloon_alert(user, "blocked!")
+			for (var/mob/living/carbon/carbon_sitter in buckled_mobs)
+				if (carbon_sitter.body_position == LYING_DOWN)
+					balloon_alert_to_viewers("blocked!")
+					return
+		var/mob/living/dropped_liver = dropped
+		if (dropped_liver.has_buckled_mobs())
+			//This sucks
+			balloon_alert_to_viewers("blocked!")
+			return
+		if (iscarbon(dropped_liver))
+			var/mob/living/carbon/dropped_carbon = dropped_liver
+			if (dropped_carbon.body_position == LYING_DOWN && has_buckled_mobs())
+				balloon_alert_to_viewers("stand up!")
+				return
 		return ..()
 	var/obj/dropped_obj = dropped
 	return load(dropped_obj)
@@ -333,16 +351,15 @@
 	unbuckle_mob(passenger, TRUE)
 
 /obj/golfcart_rear/is_buckle_possible(mob/living/target, force, check_loc)
-	. = ..()
 	// these are to_viewers because you can buckle someone on their behalf
-	if (parent && cargo)
+	if (cargo)
 		balloon_alert_to_viewers("blocked!")
 		return FALSE
 	if (target.body_position != STANDING_UP)
-		if (!has_buckled_mobs())
-			return TRUE
-		balloon_alert_to_viewers("stand up!")
-		return FALSE
+		if (has_buckled_mobs())
+			balloon_alert_to_viewers("stand up!")
+			return FALSE
+		return ..()
 	for (var/mob/blocker in buckled_mobs)
 		if (!isliving(blocker))
 			balloon_alert_to_viewers("blocked!")
@@ -351,18 +368,26 @@
 		if (living_blocker.body_position != STANDING_UP)
 			balloon_alert_to_viewers("blocked!")
 			return FALSE
-	return TRUE
+	return ..()
+
+///Called on COMSIG_MOVABLE_PREBUCKLE for anything that's buckled to us. Disallows stacking buckles
+/obj/golfcart_rear/proc/on_attempted_bucklestack()
+	SIGNAL_HANDLER
+
+	return COMPONENT_BLOCK_BUCKLE
 
 /obj/golfcart_rear/post_buckle_mob(mob/living/buckled_mob)
 	buckled_mob.pulledby?.stop_pulling()
 	RegisterSignal(buckled_mob, COMSIG_ATOM_TRIED_PASS, PROC_REF(allow_movement_between_bed_passengers))
 	RegisterSignal(buckled_mob, COMSIG_LIVING_SET_BODY_POSITION, PROC_REF(passenger_falling_down))
+	RegisterSignal(buckled_mob, COMSIG_MOVABLE_PREBUCKLE, PROC_REF(on_attempted_bucklestack))
 	. = ..()
 	update_passenger_layers()
 
 /obj/golfcart_rear/post_unbuckle_mob(mob/living/buckled_mob)
 	UnregisterSignal(buckled_mob, COMSIG_ATOM_TRIED_PASS)
 	UnregisterSignal(buckled_mob, COMSIG_LIVING_SET_BODY_POSITION)
+	UnregisterSignal(buckled_mob, COMSIG_MOVABLE_PREBUCKLE)
 	buckled_mob.remove_offsets(GOLFCART_RIDING_SOURCE)
 	if (buckled_mob.body_position == LYING_DOWN)
 		buckled_mob.layer = LYING_MOB_LAYER