## AvatarVisualizer
##
## Renders an AvatarLoadout into a 3D node tree for previews (the customization
## screen). A thin wrapper over AvatarLoader -- it owns its own loader instance
## and catalog reference so building a preview never disturbs AvatarSystem's
## live in-world avatar state.
##
## Usage:
##   var viz := AvatarVisualizer.new()
##   viz.load_loadout(loadout, preview_root_node3d)   # preview_root gets the avatar as a child
##   ...
##   viz.clear()

class_name AvatarVisualizer
extends Object

# Preloaded rather than referenced by global class_name -- see avatar_loadout.gd.
const AvatarLoadout := preload("res://scripts/avatar/avatar_loadout.gd")
const AvatarLoader := preload("res://scripts/avatar/avatar_loader.gd")
const AvatarCatalog := preload("res://scripts/avatar/avatar_catalog.gd")
const AvatarSlotRegistry := preload("res://scripts/avatar/avatar_slot_registry.gd")

## Emitted when the visualizer has finished building the render tree.
signal build_complete
## Emitted when the visualizer has been cleared.
signal cleared

## The node the assembled avatar is parented under.
var root: Node3D = null

## The assembled avatar node (child of `root`).
var avatar_node: Node3D = null

## The loadout currently rendered.
var current_loadout: AvatarLoadout = null

var _loader = null
var _catalog = null


## Build the avatar for [param loadout] and parent it under [param root_node]
## (or the previously-set `root`). Replaces any previously-built avatar.
func load_loadout(loadout, root_node: Node3D = null) -> void:
	if root_node != null:
		root = root_node
	if root == null or loadout == null:
		return

	clear()
	current_loadout = loadout

	if _catalog == null:
		var sys = root.get_node_or_null("/root/AvatarSystem")
		if sys != null:
			_catalog = sys.catalog
		if _catalog == null:
			_catalog = AvatarCatalog.new()
			_catalog.load_catalog("res://assets/avatars/catalog.json")

	_loader = AvatarLoader.new()
	root.add_child(_loader)
	_loader.init_loader(_catalog)

	var base: Node3D = _loader.load_base_body(loadout.base_body)
	if base == null:
		return
	root.add_child(base)
	avatar_node = base

	for slot_id in AvatarSlotRegistry.SLOT_IDS:
		var value = loadout.slots.get(slot_id)
		if slot_id == "accessory":
			if value is Array:
				for aid in value:
					if aid is String and not (aid as String).is_empty():
						_loader.load_attachment(slot_id, aid)
		elif value is String and not (value as String).is_empty():
			_loader.load_attachment(slot_id, value)

	for slot_id in AvatarSlotRegistry.BODY_PART_SLOTS:
		var value = loadout.slots.get(slot_id)
		if value is String and not (value as String).is_empty():
			_loader.set_base_mesh_visible(slot_id, false)

	build_complete.emit()


## Tear down the current preview avatar.
func clear() -> void:
	if avatar_node != null and is_instance_valid(avatar_node):
		avatar_node.queue_free()
	avatar_node = null
	if _loader != null and is_instance_valid(_loader):
		_loader.queue_free()
	_loader = null
	current_loadout = null
	cleared.emit()


func get_root() -> Node3D:
	return root


func get_all_mesh_instances() -> Array[MeshInstance3D]:
	var out: Array[MeshInstance3D] = []
	if avatar_node:
		_collect_meshes(avatar_node, out)
	return out


func _collect_meshes(node: Node, out: Array[MeshInstance3D]) -> void:
	if node is MeshInstance3D:
		out.append(node)
	for child in node.get_children():
		_collect_meshes(child, out)