/obj/item/epidermal_applicator
	name = "epidermal applicator"
	desc = "A pen-shaped device developed by Zeng-Hu Pharmaceuticals and used to apply synthetic skin to prosthetic limbs."
	icon = 'icons/obj/surgery.dmi'
	icon_state = "skin_applicator"
	origin_tech = "biotech=5;materials=3;engineering=4"
	new_attack_chain = TRUE

	/// Current amount of metal stored in the applicator
	var/metal_stored = 0
	/// Maximum metal that can be stored
	var/max_metal_stored = 5
	/// Metal required per application
	var/metal_per_use = 5

	var/applying = FALSE

/obj/item/epidermal_applicator/Initialize(mapload)
	. = ..()
	// Start with empty storage
	metal_stored = 0

/obj/item/epidermal_applicator/examine(mob/user)
	. = ..()

	if(metal_stored >= metal_per_use)
		. += SPAN_NOTICE("It is loaded and ready to apply an epidermal layer to a body part.")
	else
		. += SPAN_NOTICE("It needs [metal_per_use - metal_stored] more metal sheets.")

/obj/item/epidermal_applicator/proc/is_insertion_ready(mob/user)
	if(!user)
		return FALSE
	return TRUE

/obj/item/epidermal_applicator/item_interaction(mob/living/user, obj/item/used, list/modifiers)
	if(!istype(used, /obj/item/stack/sheet/metal))
		return NONE

	var/space_left = max_metal_stored - metal_stored
	if(space_left <= 0)
		to_chat(user, SPAN_NOTICE("[src] is already full!"))
		return ITEM_INTERACT_COMPLETE

	var/obj/item/stack/sheet/metal/M = used
	var/to_load = min(space_left, M.amount)
	M.use(to_load)
	metal_stored += to_load

	to_chat(user, SPAN_NOTICE("You load [to_load] sheet\s of metal into [src]."))
	return ITEM_INTERACT_COMPLETE

/obj/item/epidermal_applicator/activate_self(mob/user)
	. = ..()
	attack(user, user, null)

/obj/item/epidermal_applicator/attack(mob/living/M, mob/living/user, params)
	. = ..(M, user, params)
	if(.)
		return .

	if(!ishuman(M))
		return

	var/def_zone = user.zone_selected
	if(!def_zone)
		to_chat(user, SPAN_WARNING("You need to select a body part first!</span>"))
		return TRUE

	var/mob/living/carbon/human/target = M
	var/obj/item/organ/external/affected = target.get_organ(def_zone)

	if(!affected)
		to_chat(user, SPAN_WARNING("[target] doesn't have a [parse_zone(def_zone)]!"))
		return TRUE

	// Show these identically so it can't be used to test whether a limb is synthetic or not.
	if(!affected.is_robotic() || affected.has_synthetic_skin)
		to_chat(user, SPAN_WARNING("The [affected.name] doesn't need skin."))
		return TRUE

	// Do not put skin on a monitor. No.
	if(ismachineperson(target) && def_zone == BODY_ZONE_HEAD && affected.model)
		var/datum/robolimb/R = GLOB.all_robolimbs[affected.model]
		if(R && R.is_monitor)
			to_chat(user, SPAN_WARNING("The applicator fails to find purchase on your big cube head. Probably for the best."))
			return TRUE

	// Check if we have enough metal
	if(metal_stored < metal_per_use)
		to_chat(user, SPAN_WARNING("[src] needs [metal_per_use] metal to function."))
		return TRUE

	if(applying)
		to_chat(user, SPAN_WARNING("[src] is already in use!"))
		return TRUE

	// Start application process
	apply_synthetic_skin(target, affected, user, def_zone)
	return TRUE

/obj/item/epidermal_applicator/proc/apply_synthetic_skin(mob/living/carbon/human/target, obj/item/organ/external/affected, mob/living/user, def_zone)
	applying = TRUE

	var/chosen_identity = "Unknown" // Default identity

	// Ask for identity choice if applying to head
	if(def_zone == BODY_ZONE_HEAD)
		var/list/identity_choices = list("Unknown")
		var/list/choice_map = list("Unknown" = "Unknown")

		// Add real name option
		if(target.dna?.real_name)
			var/real_name_choice = "[target.dna.real_name]"
			identity_choices += real_name_choice
			choice_map[real_name_choice] = target.dna.real_name

		// Check for offhand ID
		var/obj/item/offhand_item = user.get_inactive_hand()
		var/offhand_id_name = null
		if(istype(offhand_item, /obj/item/card/id))
			var/obj/item/card/id/id_card = offhand_item
			offhand_id_name = id_card.registered_name
		else if(is_pda(offhand_item))
			var/obj/item/pda/pda = offhand_item
			offhand_id_name = pda.owner

		// Add ID name option if found
		if(offhand_id_name && offhand_id_name != "")
			var/id_name_choice = "[offhand_id_name]"
			identity_choices += id_name_choice
			choice_map[id_name_choice] = offhand_id_name

		// Present choice to user
		var/chosen_identity_option = tgui_input_list(user, "Choose facial identity:", "Identity Selection", identity_choices)
		if(!chosen_identity_option)
			applying = FALSE
			return // Cancel if no choice made

		chosen_identity = choice_map[chosen_identity_option]

	user.visible_message(
		SPAN_NOTICE("[user] begins applying synthetic skin to [target == user ? "their" : "[target]'s"] [affected.name] with [src]."),
		SPAN_NOTICE("You begin applying synthetic skin to [target == user ? "your" : "[target]'s"] [affected.name]...")
	)

	// Play start sound
	playsound(get_turf(src), 'sound/effects/spray.ogg', 50, TRUE)

	// 10 second do-after
	if(do_after(user, 10 SECONDS, target = target))
		// Play end sound
		playsound(get_turf(src), 'sound/effects/spray3.ogg', 50, TRUE)

		// Consume metal
		metal_stored -= metal_per_use

		// Apply synthetic skin
		affected.has_synthetic_skin = TRUE

		// Apply owner skin color to synthetic skin
		if(ishuman(target))
			affected.synthetic_skin_colour = target.skin_colour

		// Set identity if applying to head (we already got the choice above)
		if(def_zone == BODY_ZONE_HEAD)
			affected.synthetic_skin_identity = chosen_identity
			if(ishuman(target))
				target.real_name = chosen_identity

		// Clear force_icon so it unsticks from the robotic sprites
		affected.force_icon = null

		// Apply to connected torso parts as well
		if(def_zone == BODY_ZONE_CHEST)
			var/obj/item/organ/external/groin_limb = target.bodyparts_by_name["groin"]
			if(groin_limb && groin_limb.is_robotic() && !groin_limb.has_synthetic_skin)
				groin_limb.has_synthetic_skin = TRUE
				groin_limb.synthetic_skin_colour = target.skin_colour
				groin_limb.force_icon = null
				groin_limb.mob_icon = null
				groin_limb.compile_icon()

		if(def_zone == BODY_ZONE_PRECISE_GROIN)
			var/obj/item/organ/external/chest_limb = target.bodyparts_by_name["chest"]
			if(chest_limb && chest_limb.is_robotic() && !chest_limb.has_synthetic_skin)
				chest_limb.has_synthetic_skin = TRUE
				chest_limb.synthetic_skin_colour = target.skin_colour
				chest_limb.force_icon = null
				chest_limb.mob_icon = null
				chest_limb.compile_icon()

		// Force the organ to completely regenerate its mob_icon
		affected.mob_icon = null
		affected.compile_icon()

		// Force complete body rebuild to bypass icon cache
		target.update_body(rebuild_base = TRUE)
		target.UpdateDamageIcon()

		user.visible_message(
			SPAN_NOTICE("[user] applies synthetic skin to [target == user ? "their" : "[target]'s"] [affected.name]."),
			SPAN_NOTICE("You apply synthetic skin to [target == user ? "your" : "[target]'s"] [affected.name].")
		)

		if(target != user)
			to_chat(target, SPAN_NOTICE("You feel a thin layer of synthetic skin form over your [affected.name]."))

	applying = FALSE