extends Node
## SkinManager — Applies cosmetic material overrides / overlays to 3D character nodes.
##
## HOW TO ADD A NEW SKIN (edit this file only):
##   Append an entry to SKIN_CATALOG below. Format:
##
##   "item_id": {
##     "category":  "head",          # head | costume | glove | accessory
##     "character": "Oldpop",        # node name under CharacterRoot
##     "slots": [
##       { "mesh": "oldpop-hat1", "mode": "override", "material": "res://..." },
##       # mode: "override" → set_surface_override_material(0, mat)
##       # mode: "overlay"  → material_overlay  (transparent layer over base)
##       # Leave "material" as "" if the .tres file isn't ready yet — slot is skipped.
##     ]
##   },

# To add/edit/delete skins, open the editor tool:
#   scenes/tools/skin_catalog_editor.tscn  (run it in the editor)
# Or edit SKIN_CATALOG directly below — then click "Save & Generate" in the editor to sync.

## [BEGIN_SKIN_CATALOG]
const SKIN_CATALOG: Dictionary = {

	# ── [HEAD] ──────────────────────────────────────────────────────────────────────
	"oldpop-blue-hat": {
		"category":  "head",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-hat1", "mode": "override", "material": "res://assets/characters/skins/hat/oldpop_mat_hat_blue.tres" },
		]
	},
	"oldpop-green-hat": {
		"category":  "head",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-hat1", "mode": "override", "material": "res://assets/characters/skins/hat/oldpop_mat_hat_green.tres" },
		]
	},
	"oldpop-red-hat": {
		"category":  "head",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-hat1", "mode": "override", "material": "res://assets/characters/skins/hat/oldpop_mat_hat_red.tres" },
		]
	},
	"oldpop-yellow-hat": {
		"category":  "head",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-hat1", "mode": "override", "material": "res://assets/characters/skins/hat/oldpop_mat_hat_yellow.tres" },
		]
	},

	# ── [COSTUME] ──────────────────────────────────────────────────────────────────────
	"oldpop-og-pant": {
		"category":  "costume",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-body", "mode": "overlay", "material": "res://assets/characters/skins/clothing/oldpop_mat_cloth_ori_pant.tres" },
			{ "mesh": "oldpop-bottom1", "mode": "override", "material": "res://assets/characters/skins/clothing/oldpop_mat_cloth_ori_pant.tres" },
			{ "mesh": "oldpop-bottom2", "mode": "override", "material": "res://assets/characters/skins/clothing/oldpop_mat_cloth_ori_pant.tres" },
		]
	},
	"oldpop-grey-pant": {
		"category":  "costume",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-body", "mode": "overlay", "material": "res://assets/characters/skins/clothing/oldpop_mat_cloth_grey_pant.tres" },
			{ "mesh": "oldpop-bottom1", "mode": "override", "material": "res://assets/characters/skins/clothing/oldpop_mat_cloth_grey_pant.tres" },
			{ "mesh": "oldpop-bottom2", "mode": "override", "material": "res://assets/characters/skins/clothing/oldpop_mat_cloth_grey_pant.tres" },
		]
	},
	"oldpop-red-pant": {
		"category":  "costume",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-body", "mode": "overlay", "material": "res://assets/characters/skins/clothing/oldpop_mat_cloth_red_pant.tres" },
			{ "mesh": "oldpop-bottom1", "mode": "override", "material": "res://assets/characters/skins/clothing/oldpop_mat_cloth_red_pant.tres" },
			{ "mesh": "oldpop-bottom2", "mode": "override", "material": "res://assets/characters/skins/clothing/oldpop_mat_cloth_red_pant.tres" },
		]
	},
	"oldpop-yellow-pant": {
		"category":  "costume",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-body", "mode": "overlay", "material": "res://assets/characters/skins/clothing/bmo_redpants.tres" },
			{ "mesh": "oldpop-bottom1", "mode": "override", "material": "res://assets/characters/skins/clothing/bmo_redpants.tres" },
			{ "mesh": "oldpop-bottom2", "mode": "override", "material": "res://assets/characters/skins/clothing/bmo_redpants.tres" },
		]
	},

	# ── [GLOVE] ──────────────────────────────────────────────────────────────────────
	"oldpop-blue-gloves": {
		"category":  "glove",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-hands", "mode": "override", "material": "res://assets/characters/skins/gloves/oldpop_mat_gloves_blue.tres" },
		]
	},
	"oldpop-green-gloves": {
		"category":  "glove",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-hands", "mode": "override", "material": "res://assets/characters/skins/gloves/oldpop_mat_gloves_green.tres" },
		]
	},
	"oldpop-red-gloves": {
		"category":  "glove",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-hands", "mode": "override", "material": "res://assets/characters/skins/gloves/oldpop_mat_gloves_red.tres" },
		]
	},
	"oldpop-yellow-gloves": {
		"category":  "glove",
		"character": "Oldpop",
		"slots": [
			{ "mesh": "oldpop-hands", "mode": "override", "material": "res://assets/characters/skins/gloves/oldpop_mat_gloves_yellow.tres" },
		]
	},

}
## [END_SKIN_CATALOG]

# ─────────────────────────────────────────────────────────────────────────────
# Cached materials (loaded once, reused)
# ─────────────────────────────────────────────────────────────────────────────
var _mat_cache: Dictionary = {}

# ─────────────────────────────────────────────────────────────────────────────
# Public API
# ─────────────────────────────────────────────────────────────────────────────

## Apply a single skin item onto the character model.
func apply_skin(character_root: Node3D, item_id: String) -> void:
	var skin: Dictionary = SKIN_CATALOG.get(item_id, {})
	if skin.is_empty():
		push_warning("[SkinManager] Unknown item_id: " + item_id)
		return
	_apply_skin_data(character_root, skin)


## Apply every equipped item from a loadout dict { category: item_id }.
## Clears all known skin slots first so unequipped items are visually removed.
func apply_loadout(character_root: Node3D, loadout: Dictionary) -> void:
	if not character_root:
		return
	# Clear all slots before applying — handles unequip correctly on all targets
	_clear_all_skins(character_root)
	for _category: String in loadout:
		var item_id: String = loadout.get(_category, "")
		if not item_id.is_empty():
			apply_skin(character_root, item_id)


## Clear all material overrides/overlays for a given category.
func clear_category(character_root: Node3D, category: String) -> void:
	if not character_root:
		return
	for item_id: String in SKIN_CATALOG:
		var skin: Dictionary = SKIN_CATALOG[item_id]
		if skin.get("category", "") != category:
			continue
		var char_node := _get_char_node(character_root, skin.get("character", ""))
		if char_node:
			for slot: Dictionary in skin.get("slots", []):
				_clear_slot(char_node, slot)


## Clear every skin slot across all categories. Used by apply_loadout.
func _clear_all_skins(character_root: Node3D) -> void:
	if not character_root:
		return
	for item_id: String in SKIN_CATALOG:
		var skin: Dictionary = SKIN_CATALOG[item_id]
		var char_node := _get_char_node(character_root, skin.get("character", ""))
		if char_node:
			for slot: Dictionary in skin.get("slots", []):
				_clear_slot(char_node, slot)


## Preview a skin temporarily. Returns a Callable that reverts the change.
##   var revert = SkinManager.preview_skin(root, "oldpop_hat1")
##   revert.call()   # when done
func preview_skin(character_root: Node3D, item_id: String) -> Callable:
	var skin: Dictionary = SKIN_CATALOG.get(item_id, {})
	if skin.is_empty():
		return func(): pass

	var char_node := _get_char_node(character_root, skin.get("character", ""))
	if not char_node:
		return func(): pass

	# Snapshot existing materials before applying preview
	var snapshots: Array[Dictionary] = []
	for slot: Dictionary in skin.get("slots", []):
		var mn := char_node.find_child(slot.get("mesh", ""), true, false) as MeshInstance3D
		if not mn:
			continue
		var mode: String = slot.get("mode", "override")
		snapshots.append({
			"mesh_node": mn,
			"mode":      mode,
			"prev":      mn.material_overlay if mode == "overlay" else mn.get_surface_override_material(0),
		})

	_apply_skin_data(character_root, skin)

	return func():
		for snap: Dictionary in snapshots:
			var mn := snap["mesh_node"] as MeshInstance3D
			if not mn: continue
			if snap["mode"] == "overlay":
				mn.material_overlay = snap["prev"]
			else:
				mn.set_surface_override_material(0, snap["prev"])

# ─────────────────────────────────────────────────────────────────────────────
# Internals
# ─────────────────────────────────────────────────────────────────────────────

func _apply_skin_data(character_root: Node3D, skin: Dictionary) -> void:
	var char_node := _get_char_node(character_root, skin.get("character", ""))
	if not char_node:
		push_warning("[SkinManager] Character node not found: " + skin.get("character", "?"))
		return
	for slot: Dictionary in skin.get("slots", []):
		var mesh_name: String = slot.get("mesh", "")
		var mode: String      = slot.get("mode", "override")
		var mat_path: String  = slot.get("material", "")
		if mesh_name.is_empty() or mat_path.is_empty():
			continue  # Material not provided yet — skip gracefully
		var mat: Material = _load_material(mat_path)
		if not mat:
			push_warning("[SkinManager] Material not found: " + mat_path)
			continue
		var mn := char_node.find_child(mesh_name, true, false) as MeshInstance3D
		if not mn:
			push_warning("[SkinManager] Mesh '%s' not found in '%s'" % [mesh_name, char_node.name])
			continue
		if mode == "overlay":
			mn.material_overlay = mat
		else:
			# PRESERVE OUTLINE SHADER: Check if existing material has a next_pass (outline shader)
			var existing_mat = mn.get_surface_override_material(0)
			var preserved_next_pass = null
			if existing_mat and existing_mat.next_pass:
				preserved_next_pass = existing_mat.next_pass
			
			# Apply the skin material
			var skin_mat = mat.duplicate() if mat else null
			if skin_mat and preserved_next_pass:
				skin_mat.next_pass = preserved_next_pass
			
			mn.set_surface_override_material(0, skin_mat)


func _clear_slot(char_node: Node3D, slot: Dictionary) -> void:
	var mesh_name: String = slot.get("mesh", "")
	var mode: String      = slot.get("mode", "override")
	if mesh_name.is_empty(): return
	var mn := char_node.find_child(mesh_name, true, false) as MeshInstance3D
	if not mn: return
	if mode == "overlay":
		mn.material_overlay = null
	else:
		# PRESERVE OUTLINE SHADER: When clearing, check if we need to restore outline
		var existing_mat = mn.get_surface_override_material(0)
		if existing_mat and existing_mat.next_pass:
			# Has outline - restore base material with outline preserved
			var base_mat = mn.get_active_material(0)
			if base_mat:
				var restored_mat = base_mat.duplicate()
				restored_mat.next_pass = existing_mat.next_pass
				mn.set_surface_override_material(0, restored_mat)
			else:
				# No base material, just clear but this shouldn't happen normally
				mn.set_surface_override_material(0, null)
		else:
			mn.set_surface_override_material(0, null)


func _get_char_node(character_root: Node3D, char_name: String) -> Node3D:
	if char_name.is_empty() or not character_root: return null
	return character_root.get_node_or_null(char_name) as Node3D


func _load_material(path: String) -> Material:
	if _mat_cache.has(path):
		return _mat_cache[path]
	if not ResourceLoader.exists(path):
		return null
	var mat := ResourceLoader.load(path) as Material
	_mat_cache[path] = mat
	return mat