Spiderling Pathing Tweaks (#15151)

* Spiderling Pathing Tweaks

* fixes spiderling/rechargestation interaction the right way

* Steel suggestion

Co-authored-by: SteelSlayer <42044220+SteelSlayer@users.noreply.github.com>

Co-authored-by: Kyep <Kyep@users.noreply.github.com>
Co-authored-by: SteelSlayer <42044220+SteelSlayer@users.noreply.github.com>

code/game/objects/effects/spiders.dm

@@ -156,12 +156,8 @@
 	//=================
 
 	else if(prob(33))
-		var/list/nearby = oview(10, src)
-		if(nearby.len)
-			var/target_atom = pick(nearby)
-			walk_to(src, target_atom)
-			if(prob(40))
-				visible_message("<span class='notice'>[src] skitters[pick(" away"," around","")].</span>")
+		if(random_skitter() && prob(40))
+			visible_message("<span class='notice'>[src] skitters[pick(" away"," around","")].</span>")
 	else if(prob(10))
 		//ventcrawl!
 		for(var/obj/machinery/atmospherics/unary/vent_pump/v in view(7,src))
@@ -190,6 +186,18 @@
 								to_chat(S, "<span class='biggerdanger'>You are a spider who is loyal to [S.master_commander], obey [S.master_commander]'s every order and assist [S.master_commander.p_them()] in completing [S.master_commander.p_their()] goals at any cost.</span>")
 			qdel(src)
 
+/obj/structure/spider/spiderling/proc/random_skitter()
+	var/list/available_turfs = list()
+	for(var/turf/simulated/S in oview(10, src))
+		// no !isspaceturf check needed since /turf/simulated is not a subtype of /turf/space
+		if(S.density)
+			continue
+		available_turfs += S
+	if(!length(available_turfs))
+		return FALSE
+	walk_to(src, pick(available_turfs))
+	return TRUE
+
 /obj/structure/spider/spiderling/decompile_act(obj/item/matter_decompiler/C, mob/user)
 	if(!istype(user, /mob/living/silicon/robot/drone))
 		user.visible_message("<span class='notice'>[user] sucks [src] into its decompiler. There's a horrible crunching noise.</span>", \