migrates /obj/effect to the new attack chain

code/datums/spells/spacetime_dist.dm

@@ -122,11 +122,12 @@
 	if(!cant_teleport)
 		walk_link(entered)
 
-/obj/effect/cross_action/spacetime_dist/attackby__legacy__attackchain(obj/item/W, mob/user, params)
-	if(user.drop_item(W))
-		walk_link(W)
+/obj/effect/cross_action/spacetime_dist/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(user.drop_item(used))
+		walk_link(used)
 	else
 		walk_link(user)
+	return ITEM_INTERACT_COMPLETE
 
 //ATTACK HAND IGNORING PARENT RETURN VALUE
 /obj/effect/cross_action/spacetime_dist/attack_hand(mob/user, list/modifiers)

code/game/gamemodes/cult/cult_items.dm

@@ -811,13 +811,12 @@
 	if(target)
 		exit = new /obj/effect/cult_portal_exit(target)
 
-/obj/effect/portal/cult/attackby__legacy__attackchain(obj/I, mob/user, params)
-	if(istype(I, /obj/item/melee/cultblade/dagger) && IS_CULTIST(user) || istype(I, /obj/item/nullrod) && HAS_MIND_TRAIT(user, TRAIT_HOLY))
-		to_chat(user, "<span class='notice'>You close the portal with your [I].</span>")
+/obj/effect/portal/cult/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(istype(used, /obj/item/melee/cultblade/dagger) && IS_CULTIST(user) || istype(used, /obj/item/nullrod) && HAS_MIND_TRAIT(user, TRAIT_HOLY))
+		to_chat(user, "<span class='notice'>You close the portal with your [used].</span>")
 		playsound(src, 'sound/magic/magic_missile.ogg', 100, TRUE)
 		qdel(src)
-		return
-	return ..()
+		return ITEM_INTERACT_COMPLETE
 
 /obj/effect/portal/cult/Destroy()
 	QDEL_NULL(exit)

code/game/gamemodes/cult/runes.dm

@@ -75,27 +75,28 @@ To draw a rune, use a ritual dagger.
 		if(req_keyword && keyword)
 			. += "<b>Keyword:</b> <span class='cultitalic'>[keyword]</span>"
 
-/obj/effect/rune/attackby__legacy__attackchain(obj/I, mob/user, params)
-	if(istype(I, /obj/item/melee/cultblade/dagger) && IS_CULTIST(user))
+/obj/effect/rune/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(istype(used, /obj/item/melee/cultblade/dagger) && IS_CULTIST(user))
 		if(!can_dagger_erase_rune(user))
-			return
+			return ITEM_INTERACT_COMPLETE
 
-		var/obj/item/melee/cultblade/dagger/D = I
-		user.visible_message("<span class='warning'>[user] begins to erase [src] with [I].</span>")
-		if(do_after(user, initial(scribe_delay) * D.scribe_multiplier, target = src))
+		var/obj/item/melee/cultblade/dagger/dagger = used
+		user.visible_message("<span class='warning'>[user] begins to erase [src] with [dagger].</span>")
+		if(do_after(user, initial(scribe_delay) * dagger.scribe_multiplier, target = src))
 			to_chat(user, "<span class='notice'>You carefully erase the [lowertext(cultist_name)] rune.</span>")
 			qdel(src)
-		return
-	if(istype(I, /obj/item/nullrod))
-		if(IS_CULTIST(user))//cultist..what are doing..cultist..staph...
+		return ITEM_INTERACT_COMPLETE
+
+	if(istype(used, /obj/item/nullrod))
+		var/obj/item/nullrod/nullrod = used
+		if(IS_CULTIST(user)) // cultist..what are doing..cultist..staph...
 			user.drop_item()
-			user.visible_message("<span class='warning'>[I] suddenly glows with a white light, forcing [user] to drop it in pain!</span>", \
-			"<span class='danger'>[I] suddenly glows with a white light that sears your hand, forcing you to drop it!</span>") // TODO: Make this actually burn your hand
-			return
-		to_chat(user,"<span class='danger'>You disrupt the magic of [src] with [I].</span>")
+			user.visible_message("<span class='warning'>[nullrod] suddenly glows with a white light, forcing [user] to drop it in pain!</span>", \
+			"<span class='danger'>[nullrod] suddenly glows with a white light that sears your hand, forcing you to drop it!</span>") // TODO: Make this actually burn your hand
+			return ITEM_INTERACT_COMPLETE
+		to_chat(user,"<span class='danger'>You disrupt the magic of [src] with [nullrod].</span>")
 		qdel(src)
-		return
-	return ..()
+		return ITEM_INTERACT_COMPLETE
 
 /obj/effect/rune/proc/can_dagger_erase_rune(mob/user)
 	return TRUE
@@ -1097,11 +1098,11 @@ structure_check() searches for nearby cultist structures required for the invoca
 	sleep(40)
 	new /obj/singularity/narsie/large(T) //Causes Nar'Sie to spawn even if the rune has been removed
 
-/obj/effect/rune/narsie/attackby__legacy__attackchain(obj/I, mob/user, params)	//Since the narsie rune takes a long time to make, add logging to removal.
-	if((istype(I, /obj/item/melee/cultblade/dagger) && IS_CULTIST(user)))
+/obj/effect/rune/narsie/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	..()
+	if((istype(used, /obj/item/melee/cultblade/dagger) && IS_CULTIST(user)))
 		log_game("Summon Narsie rune erased by [key_name(user)] with a cult dagger")
 		message_admins("[key_name_admin(user)] erased a Narsie rune with a cult dagger")
-	if(istype(I, /obj/item/nullrod))	//Begone foul magiks. You cannot hinder me.
+	if(istype(used, /obj/item/nullrod))	//Begone foul magiks. You cannot hinder me.
 		log_game("Summon Narsie rune erased by [key_name(user)] using a null rod")
 		message_admins("[key_name_admin(user)] erased a Narsie rune with a null rod")
-	return ..()

code/game/gamemodes/miniantags/guardian/types/protector.dm

@@ -137,10 +137,13 @@
 	P.on_hit(src, 0)
 	return FALSE
 
-/obj/effect/guardianshield/attacked_by__legacy__attackchain(obj/item/I, mob/living/user)
-	if(I.force)
-		user.visible_message("<span class='danger'>[user] has hit [src] with [I]!</span>", "<span class='danger'>You hit [src] with [I]!</span>")
-	linked_guardian.apply_damage(I.force, I.damtype)
+/obj/effect/guardianshield/attack_by(obj/item/attacking, mob/user, params)
+	if(..() || !attacking.force)
+		return FINISH_ATTACK
+
+	user.visible_message("<span class='danger'>[user] has hit [src] with [attacking]!</span>", "<span class='danger'>You hit [src] with [attacking]!</span>")
+	linked_guardian.apply_damage(attacking.force, attacking.damtype)
+	return FINISH_ATTACK
 
 /obj/effect/guardianshield/Destroy()
 	linked_guardian = null

code/game/gamemodes/wizard/artefact.dm

@@ -128,12 +128,11 @@
 	if(spawn_amt_left <= 0)
 		qdel(src)
 
-/obj/effect/rend/attackby__legacy__attackchain(obj/item/I as obj, mob/user as mob)
-	if(istype(I, /obj/item/nullrod))
-		user.visible_message("<span class='danger'>[user] seals \the [src] with \the [I].</span>")
+/obj/effect/rend/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(istype(used, /obj/item/nullrod))
+		user.visible_message("<span class='danger'>[user] seals \the [src] with \the [used].</span>")
 		qdel(src)
-		return
-	return ..()
+		return ITEM_INTERACT_COMPLETE
 
 /obj/effect/rend/singularity_pull()
 	return

code/game/objects/effects/anomalies.dm

@@ -94,9 +94,10 @@
 	// Else, anomaly core gets deleted by qdel(src).
 	qdel(src)
 
-/obj/effect/anomaly/attackby__legacy__attackchain(obj/item/I, mob/user, params)
-	if(istype(I, /obj/item/analyzer))
+/obj/effect/anomaly/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(istype(used, /obj/item/analyzer))
 		to_chat(user, "<span class='notice'>Analyzing... [src]'s unstable field is fluctuating along frequency [format_frequency(aSignal.frequency)], code [aSignal.code].</span>")
+		return ITEM_INTERACT_COMPLETE
 
 /obj/effect/anomaly/grav
 	name = "gravitational anomaly"

code/game/objects/effects/decals/Cleanable/tar.dm

@@ -38,11 +38,13 @@
 		playsound(L, 'sound/effects/attackblob.ogg', 50, TRUE)
 		to_chat(L, "<span class='userdanger'>[src] sticks to you!</span>")
 
-/obj/effect/decal/cleanable/tar/attackby__legacy__attackchain(obj/item/welder, mob/living/user, params)
-	if(!welder.get_heat() || !Adjacent(user))
-		return
-	playsound(welder, 'sound/items/welder.ogg', 50, TRUE)
+/obj/effect/decal/cleanable/tar/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	var/obj/item/weldingtool/fire_tool = used
+	if(!fire_tool.get_heat() || !Adjacent(user))
+		return ITEM_INTERACT_COMPLETE
+	playsound(fire_tool, 'sound/items/welder.ogg', 50, TRUE)
 	if(do_after(user, 3 SECONDS, FALSE, user))
-		if(welder.get_heat() && Adjacent(user))
-			user.visible_message("<span class='danger'>[user] burns away [src] with [welder]!</span>", "<span class='danger'>You burn away [src]!</span>")
+		if(fire_tool.get_heat() && Adjacent(user))
+			user.visible_message("<span class='danger'>[user] burns away [src] with [fire_tool]!</span>", "<span class='danger'>You burn away [src]!</span>")
 			qdel(src)
+			return ITEM_INTERACT_COMPLETE

code/game/objects/effects/effects.dm

@@ -8,6 +8,7 @@
 	move_resist = INFINITY
 	anchored = TRUE
 	can_be_hit = FALSE
+	new_attack_chain = TRUE
 
 /obj/effect/take_damage(damage_amount, damage_type = BRUTE, damage_flag = 0, sound_effect = 1, attack_dir)
 	return
@@ -103,11 +104,13 @@
 	if(desc)
 		. += desc
 
-/obj/effect/decal/attackby__legacy__attackchain(obj/item/I, mob/user)
-	if(istype(I, /obj/item/reagent_containers/glass) || istype(I, /obj/item/reagent_containers/drinks))
-		scoop(I, user)
+/obj/effect/decal/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(istype(used, /obj/item/reagent_containers/glass) || istype(used, /obj/item/reagent_containers/drinks))
+		scoop(used, user)
+		return ITEM_INTERACT_COMPLETE
 	else if(issimulatedturf(loc))
-		I.melee_attack_chain(user, loc)
+		used.melee_attack_chain(user, loc)
+		return ITEM_INTERACT_COMPLETE
 
 /obj/effect/decal/attack_animal(mob/living/simple_animal/M)
 	if(issimulatedturf(loc))

code/game/objects/effects/meteors.dm

@@ -146,12 +146,11 @@ GLOBAL_LIST_INIT(meteors_gore, list(/obj/effect/meteor/meaty = 5, /obj/effect/me
 /obj/effect/meteor/ex_act()
 	return
 
-/obj/effect/meteor/attackby__legacy__attackchain(obj/item/I, mob/user, params)
-	if(istype(I, /obj/item/pickaxe))
+/obj/effect/meteor/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(istype(used, /obj/item/pickaxe))
 		make_debris()
 		qdel(src)
-		return
-	return ..()
+		return ITEM_INTERACT_COMPLETE
 
 /obj/effect/meteor/proc/make_debris()
 	for(var/throws = dropamt, throws > 0, throws--)

code/game/objects/effects/snowcloud.dm

@@ -97,17 +97,15 @@
 	user.put_in_hands(SB)
 	to_chat(user, "<span class='notice'>You scoop up some snow and make \a [SB]!</span>")
 
-/obj/effect/snow/attackby__legacy__attackchain(obj/item/I, mob/user)
-	if(istype(I, /obj/item/shovel))
-		var/obj/item/shovel/S = I
+/obj/effect/snow/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(istype(used, /obj/item/shovel))
+		var/obj/item/shovel/shovel = used
 		user.visible_message("<span class='notice'>[user] is clearing away [src]...</span>", "<span class='notice'>You begin clearing away [src]...</span>", "<span class='warning'>You hear a wettish digging sound.</span>")
-		playsound(loc, S.usesound, 50, TRUE)
-		if(!do_after(user, 50 * S.toolspeed, target = src))
-			return
-		user.visible_message("<span class='notice'>[user] clears away [src]!</span>", "<span class='notice'>You clear away [src]!</span>")
-		qdel(src)
-	else
-		return ..()
+		playsound(loc, shovel.usesound, 50, TRUE)
+		if(do_after(user, 50 * shovel.toolspeed, target = src))
+			user.visible_message("<span class='notice'>[user] clears away [src]!</span>", "<span class='notice'>You clear away [src]!</span>")
+			qdel(src)	
+		return ITEM_INTERACT_COMPLETE
 
 /obj/effect/snow/fire_act(datum/gas_mixture/air, exposed_temperature, exposed_volume, global_overlay = TRUE)
 	..()

code/game/objects/items/devices/chameleonproj.dm

@@ -117,8 +117,10 @@
 	master = C
 	master.active_dummy = src
 
-/obj/effect/dummy/chameleon/attackby__legacy__attackchain()
-	for(var/mob/M in src)
+/obj/effect/dummy/chameleon/attack_by(obj/item/attacking, mob/user, params)
+	if(..())
+		return FINISH_ATTACK
+	for(var/mob/M in src)	
 		to_chat(M, "<span class='danger'>Your [src] deactivates.</span>")
 	master.disrupt()
 
@@ -186,8 +188,8 @@
 	item_state = "electronic"
 	w_class = WEIGHT_CLASS_SMALL
 	var/active = FALSE
-	var/activationCost = 300
-	var/activationUpkeep = 50
+	var/activation_cost = 300
+	var/activation_upkeep = 50
 	var/image/disguise
 	var/mob/living/silicon/robot/syndicate/saboteur/S
 
@@ -205,13 +207,13 @@
 	disrupt(user)
 
 /obj/item/borg_chameleon/attack_self__legacy__attackchain(mob/living/silicon/robot/syndicate/saboteur/user)
-	if(user && user.cell && user.cell.charge > activationCost)
+	if(user && user.cell && user.cell.charge > activation_cost)
 		if(isturf(user.loc))
 			toggle(user)
 		else
 			to_chat(user, "<span class='warning'>You can't use [src] while inside something!</span>")
 	else
-		to_chat(user, "<span class='warning'>You need at least [activationCost] charge in your cell to use [src]!</span>")
+		to_chat(user, "<span class='warning'>You need at least [activation_cost] charge in your cell to use [src]!</span>")
 
 /obj/item/borg_chameleon/proc/toggle(mob/living/silicon/robot/syndicate/saboteur/user)
 	if(active)
@@ -220,7 +222,7 @@
 		return
 	to_chat(user, "<span class='notice'>You activate [src].</span>")
 	apply_wibbly_filters(user)
-	if(do_after(user, 5 SECONDS, target = user) && user.cell.use(activationCost))
+	if(do_after(user, 5 SECONDS, target = user) && user.cell.use(activation_cost))
 		activate(user)
 	else
 		to_chat(user, "<span class='warning'>The chameleon field fizzles.</span>")
@@ -229,7 +231,7 @@
 
 /obj/item/borg_chameleon/process()
 	if(S)
-		if(!S.cell || !S.cell.use(activationUpkeep))
+		if(!S.cell || !S.cell.use(activation_upkeep))
 			disrupt(S)
 		return
 	return PROCESS_KILL

code/game/objects/items/weapons/gift_wrappaper.dm

@@ -39,19 +39,16 @@
 		return
 	to_chat(user, "<span class='notice'>You can't move.</span>")
 
-/obj/effect/spresent/attackby__legacy__attackchain(obj/item/W as obj, mob/user as mob, params)
-	..()
-
-	if(!istype(W, /obj/item/wirecutters))
+/obj/effect/spresent/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(!istype(used, /obj/item/wirecutters))
 		to_chat(user, "<span class='notice'>I need wirecutters for that.</span>")
-		return
+		return ITEM_INTERACT_COMPLETE
 
 	to_chat(user, "<span class='notice'>You cut open the present.</span>")
-
 	for(var/mob/M in src) //Should only be one but whatever.
 		M.forceMove(loc)
-
 	qdel(src)
+	return ITEM_INTERACT_COMPLETE
 
 /obj/item/a_gift/attack_self__legacy__attackchain(mob/M as mob)
 	var/gift_type = pick(

code/game/objects/items/weapons/mop.dm

@@ -70,11 +70,9 @@
 		reagents.reaction(T, REAGENT_TOUCH, 10)	//10 is the multiplier for the reaction effect. probably needed to wet the floor properly.
 	reagents.remove_any(1)			//reaction() doesn't use up the reagents
 
-/obj/effect/attackby__legacy__attackchain(obj/item/I, mob/user, params)
-	if(istype(I, /obj/item/mop) || istype(I, /obj/item/soap))
-		return
-	else
-		return ..()
+/obj/effect/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(istype(used, /obj/item/mop) || istype(used, /obj/item/soap))
+		return ITEM_INTERACT_COMPLETE
 
 /obj/item/mop/wash(mob/user, atom/source)
 	reagents.add_reagent("water", 5)

code/modules/awaymissions/mission_code/ghost_role_spawners/golems.dm

@@ -166,16 +166,13 @@
 		create(ckey = user.ckey, name = user.real_name)
 		user.death()
 
-/obj/effect/mob_spawn/human/alive/golem/attackby__legacy__attackchain(obj/item/I, mob/living/carbon/user, params)
-	if(!istype(I, /obj/item/slimepotion/transference))
-		return ..()
-	if(iscarbon(user) && can_transfer)
+/obj/effect/mob_spawn/human/alive/golem/item_interaction(mob/living/user, obj/item/used, list/modifiers)
+	if(istype(used, /obj/item/slimepotion/transference) && iscarbon(user) && can_transfer)
 		var/human_transfer_choice = tgui_alert(user, "Transfer your soul to [src]? (Warning, your old body will die!)", "Respawn", list("Yes", "No"))
-		if(human_transfer_choice != "Yes")
-			return
-		if(QDELETED(src) || uses <= 0 || user.stat >= 1 || QDELETED(I))
-			return
-		handle_becoming_golem(I, user)
+		if(human_transfer_choice != "Yes" || QDELETED(src) || uses <= 0 || user.stat >= 1 || QDELETED(used))
+			return ITEM_INTERACT_COMPLETE
+		handle_becoming_golem(used, user)
+		return ITEM_INTERACT_COMPLETE
 
 /obj/effect/mob_spawn/human/alive/golem/proc/handle_becoming_golem(obj/item/I, mob/living/carbon/user)
 	if(isgolem(user) && can_transfer)

code/modules/hallucinations/effects/major.dm

@@ -68,15 +68,15 @@
 	target.visible_message("<span class='warning'>[target] trips over nothing.</span>",
 						"<span class='userdanger'>You get stuck in [src]!</span>")
 
-/obj/effect/hallucination/tripper/spider_web/attackby__legacy__attackchain(obj/item/I, mob/user, params)
+/obj/effect/hallucination/tripper/spider_web/item_interaction(mob/living/user, obj/item/used, list/modifiers)
 	if(user != target)
-		return
-
+		return ITEM_INTERACT_COMPLETE
 	step_towards(target, get_turf(src))
 	target.Weaken(4 SECONDS)
-	target.visible_message("<span class='warning'>[target] flails [target.p_their()] [I.name] as if striking something, only to trip!</span>",
-						"<span class='userdanger'>[src] vanishes as you strike it with [I], causing you to stumble forward!</span>")
+	target.visible_message("<span class='warning'>[target] flails [target.p_their()] [used.name] as if striking something, only to trip!</span>",
+						"<span class='userdanger'>[src] vanishes as you strike it with [used], causing you to stumble forward!</span>")
 	qdel(src)
+	return ITEM_INTERACT_COMPLETE
 
 /**
   * # Hallucination - Abduction

code/modules/mining/lavaland/loot/tendril_loot.dm

@@ -449,9 +449,6 @@
 	. = ..()
 	ADD_TRAIT(src, TRAIT_EFFECT_CAN_TELEPORT, ROUNDSTART_TRAIT)
 
-/obj/effect/immortality_talisman/attackby__legacy__attackchain()
-	return
-
 /obj/effect/immortality_talisman/ex_act()
 	return