class_name FaceRig
extends Node
## 角色脸部：body_mesh 现在**只有一个材质**，所以这里不再换材质，
## 而是把 mat_body 换成「全身 shader」：身体照常取它的 BaseColor，
## 只在脸部的 UV 矩形内叠加表情贴图和玩家手绘。

const SHADER_PATH := "res://character/player/face/face_paint.gdshader"
const ATLAS_PATH := "res://character/player/face/presets/face_atlas_transparent.png"
const LEGACY_PRESET_SAVE := "user://face_preset.json"
const SAVE_PAINT := "user://face_paint.png"
const LIBRARY_DIR := "user://face_library"
const LIBRARY_INDEX := "user://face_library/index.json"

## 图集 rect 来自最初那张 1024² 表情图：face_01=(145,32,219)，face_02=(152,290,205)。
## 每个条目用各自的采样矩形，贴图都是项目里的 face_atlas_transparent.png（原图已随模型删掉）。
const BUILTIN_EXPRESSIONS := [
	{"id": "builtin:face_01", "name": "预设表情 1", "rect": Rect2(145.0 / 1024.0, 32.0 / 1024.0, 219.0 / 1024.0, 219.0 / 1024.0)},
	{"id": "builtin:face_02", "name": "预设表情 2", "rect": Rect2(152.0 / 1024.0, 290.0 / 1024.0, 205.0 / 1024.0, 205.0 / 1024.0)},
]

const FACE_SYNC_TRIES := 5
const FACE_SYNC_INTERVAL := 0.8
const FACE_SYNC_INITIAL_DELAY := 1.0

@export_group("接线")
@export var mesh_path: NodePath = ^"../Body/mouse/MouseRig/Skeleton3D/body_mesh"
## 覆盖第几个 surface。现在 body_mesh 只有一个材质 mat_body，所以是 0。
@export var surface_index: int = 0
@export var default_expression_id: String = "builtin:face_01"

@export_group("画布")
@export var canvas_size: int = 512
## 与模型身体贴图的底色一致（FaceRig 启动时会从 mat_body 的 BaseColor 左上角自动读出来）。
## 只给画布和缩略图垫底用，不参与 3D 着色。
@export var skin_color: Color = Color(0.537255, 0.701961, 1.0, 1.0)

## 表情画在哪 / 多大 / 正不正，全部写在 face_paint.gdshader 顶部的「调表情就改这一段」里
## （face_center / face_size / face_flip_y）。**FaceRig 故意不传这三个 uniform**，
## 免得脚本里的值把 shader 里调好的值盖掉。

var mesh: MeshInstance3D
var material: ShaderMaterial
var painter: FacePainter
var selected_expression_id: String = ""
var selected_expression_name: String = ""
var selected_expression_texture: Texture2D
var _atlas_texture: Texture2D
var _no_base: Texture2D
var _base_uv_min := Vector2.ZERO
var _base_uv_size := Vector2.ONE
var _got_face := false


func _ready() -> void:
	mesh = get_node_or_null(mesh_path) as MeshInstance3D
	if mesh == null:
		push_warning("%s 找不到面部 mesh（%s），脸不会有变化" % [get_path(), mesh_path])
		return

	_atlas_texture = load(ATLAS_PATH) as Texture2D
	painter = FacePainter.new(canvas_size)
	painter.name = "FacePainter"
	add_child(painter)

	material = ShaderMaterial.new()
	material.shader = load(SHADER_PATH)
	var body_material := mesh.mesh.surface_get_material(surface_index) as StandardMaterial3D
	if body_material == null:
		push_warning("%s 的 surface %d 不是 StandardMaterial3D，身体底色可能不对" % [mesh_path, surface_index])
	else:
		# 身体底色、粗糙度、金属度都照抄 mat_body —— 脸和身体才可能看起来是同一块皮肤
		var body_tex := body_material.albedo_texture
		if body_tex != null:
			material.set_shader_parameter("body_tex", body_tex)
			# 画布和缩略图垫的底色也跟着身体贴图走，省得和模型对不上。
			# 导入的贴图是压缩格式，get_pixel 之前必须先解压。
			var body_image := body_tex.get_image()
			if body_image != null:
				if body_image.is_compressed():
					body_image.decompress()
				if not body_image.is_empty():
					var body_rgb := body_image.get_pixel(0, 0)
					skin_color = Color(body_rgb.r, body_rgb.g, body_rgb.b, 1.0)
		material.set_shader_parameter("body_tint", body_material.albedo_color)
		material.set_shader_parameter("surface_roughness", body_material.roughness)
		material.set_shader_parameter("surface_metallic", body_material.metallic)
	material.set_shader_parameter("paint_tex", painter.texture)
	mesh.set_surface_override_material(surface_index, material)

	apply_saved()

	var peer := multiplayer.multiplayer_peer
	if peer != null and not (peer is OfflineMultiplayerPeer) and not is_multiplayer_authority():
		_pull_remote_face()


# ---------------- 表情列表与选择 ----------------

## 返回内置 atlas 表情和本地保存表情，供角色选择页建缩略图。
func get_expression_catalog() -> Array[Dictionary]:
	var entries: Array[Dictionary] = []
	for builtin in BUILTIN_EXPRESSIONS:
		var rect: Rect2 = builtin["rect"]
		var thumb := AtlasTexture.new()
		thumb.atlas = _atlas_texture
		thumb.region = Rect2(rect.position * Vector2(1024.0, 1024.0), rect.size * Vector2(1024.0, 1024.0))
		thumb.filter_clip = true
		entries.append({
			"id": builtin["id"], "name": builtin["name"],
			"texture": _atlas_texture, "thumbnail": thumb,
			"uv_min": rect.position, "uv_size": rect.size, "is_atlas": true,
		})

	for row in _read_library_index():
		var id := str(row.get("id", ""))
		var filename := str(row.get("file", ""))
		if id.is_empty() or filename.is_empty():
			continue
		var image := Image.load_from_file("%s/%s" % [LIBRARY_DIR, filename])
		if image == null or image.is_empty():
			continue
		var tex := ImageTexture.create_from_image(image)
		entries.append({
			"id": id, "name": str(row.get("name", "我的表情")),
			"texture": tex, "thumbnail": tex,
			"uv_min": Vector2.ZERO, "uv_size": Vector2.ONE, "is_atlas": false,
		})
	return entries


## 选择一个内置或本地表情。切换项目时清掉临时笔画，表情项本身是完整表情。
func select_expression(expression_id: String, clear_paint: bool = true) -> bool:
	for entry in get_expression_catalog():
		if str(entry["id"]) != expression_id:
			continue
		_apply_expression(entry)
		if clear_paint and painter != null:
			painter.clear()
		return true
	return false


## 「自己画」/取消快照需要的透明空白项，不保存为内置表情。
func select_blank(clear_paint: bool = true) -> void:
	selected_expression_id = ""
	selected_expression_name = "空白"
	selected_expression_texture = _no_base_texture()
	_base_uv_min = Vector2.ZERO
	_base_uv_size = Vector2.ONE
	_update_shader_expression()
	if clear_paint and painter != null:
		painter.clear()


func _apply_expression(entry: Dictionary) -> void:
	selected_expression_id = str(entry["id"])
	selected_expression_name = str(entry["name"])
	selected_expression_texture = entry["texture"] as Texture2D
	_base_uv_min = entry["uv_min"] as Vector2
	_base_uv_size = entry["uv_size"] as Vector2
	_update_shader_expression()


func _update_shader_expression() -> void:
	if material == null:
		return
	material.set_shader_parameter("base_tex", selected_expression_texture if selected_expression_texture != null else _no_base_texture())
	material.set_shader_parameter("base_uv_min", _base_uv_min)
	material.set_shader_parameter("base_uv_size", _base_uv_size)


func _no_base_texture() -> Texture2D:
	if _no_base == null:
		_no_base = ImageTexture.create_from_image(Image.create(2, 2, false, Image.FORMAT_RGBA8))
	return _no_base


# ---------------- 本地表情库 ----------------

func save_drawing_as_expression(display_name: String) -> Dictionary:
	if painter == null:
		return {}
	var absolute_dir := ProjectSettings.globalize_path(LIBRARY_DIR)
	var dir_error := DirAccess.make_dir_recursive_absolute(absolute_dir)
	if dir_error != OK and dir_error != ERR_ALREADY_EXISTS:
		push_warning("无法创建本地表情目录：%s" % error_string(dir_error))
		return {}

	var rows := _read_library_index()
	var entry_name := display_name.strip_edges()
	if entry_name.is_empty():
		entry_name = "我的表情 %d" % (rows.size() + 1)
	var id := "user:%d" % Time.get_ticks_usec()
	var filename := id.replace(":", "_") + ".png"
	var file := FileAccess.open("%s/%s" % [LIBRARY_DIR, filename], FileAccess.WRITE)
	if file == null:
		push_warning("无法保存本地表情：%s" % filename)
		return {}
	file.store_buffer(painter.to_png_bytes())
	file.close()

	rows.append({"id": id, "name": entry_name, "file": filename})
	if not _write_library_index(rows):
		return {}
	if not select_expression(id):
		return {}
	save()
	return {"id": id, "name": entry_name}


func _read_library_index() -> Array:
	if not FileAccess.file_exists(LIBRARY_INDEX):
		return []
	var file := FileAccess.open(LIBRARY_INDEX, FileAccess.READ)
	if file == null:
		return []
	var data: Variant = JSON.parse_string(file.get_as_text())
	return data if data is Array else []


func _write_library_index(rows: Array) -> bool:
	var file := FileAccess.open(LIBRARY_INDEX, FileAccess.WRITE)
	if file == null:
		push_warning("无法更新本地表情索引：%s" % LIBRARY_INDEX)
		return false
	file.store_string(JSON.stringify(rows))
	file.close()
	return true


# ---------------- 存档 ----------------

func save() -> void:
	if painter == null:
		return
	painter.save_png(SAVE_PAINT)
	var file := FileAccess.open(LEGACY_PRESET_SAVE, FileAccess.WRITE)
	if file == null:
		push_warning("脸部选择存不下来：%s" % LEGACY_PRESET_SAVE)
		return
	file.store_string(JSON.stringify({"expression_id": selected_expression_id}))
	file.close()


func apply_saved() -> void:
	var expression_id := default_expression_id
	if FileAccess.file_exists(LEGACY_PRESET_SAVE):
		var file := FileAccess.open(LEGACY_PRESET_SAVE, FileAccess.READ)
		var data: Variant = JSON.parse_string(file.get_as_text()) if file != null else null
		if data is Dictionary:
			expression_id = str(data.get("expression_id", _legacy_expression_id(str(data.get("preset", "")))))
	if expression_id.is_empty():
		select_blank(false)
	elif not select_expression(expression_id, false):
		select_expression(default_expression_id, false)
	if painter != null:
		painter.load_png(SAVE_PAINT)


func _legacy_expression_id(old_path: String) -> String:
	if old_path.is_empty():
		return ""
	if old_path.ends_with("face_02.png"):
		return "builtin:face_02"
	if old_path.ends_with("face_01.png"):
		return "builtin:face_01"
	return default_expression_id


# ---------------- 联机同步 ----------------

func _pull_remote_face() -> void:
	await get_tree().create_timer(FACE_SYNC_INITIAL_DELAY).timeout
	for i in FACE_SYNC_TRIES:
		if not is_inside_tree() or _got_face:
			return
		_rpc_request_face.rpc_id(get_multiplayer_authority())
		await get_tree().create_timer(FACE_SYNC_INTERVAL).timeout


@rpc("any_peer", "call_remote", "reliable")
func _rpc_request_face() -> void:
	if not is_multiplayer_authority():
		return
	var local_png := PackedByteArray()
	if selected_expression_id.begins_with("user:") and selected_expression_texture != null:
		var image := selected_expression_texture.get_image()
		local_png = image.save_png_to_buffer()
	_rpc_send_face.rpc_id(
		multiplayer.get_remote_sender_id(),
		selected_expression_id,
		local_png,
		painter.to_png_bytes() if painter != null else PackedByteArray(),
	)


@rpc("any_peer", "call_remote", "reliable")
func _rpc_send_face(expression_id: String, local_png: PackedByteArray, paint_png: PackedByteArray) -> void:
	if is_multiplayer_authority() or multiplayer.get_remote_sender_id() != get_multiplayer_authority():
		return
	_got_face = true
	if expression_id.is_empty():
		select_blank(false)
	elif expression_id.begins_with("user:") and local_png.size() > 0:
		var img := Image.new()
		if img.load_png_from_buffer(local_png) == OK:
			selected_expression_id = expression_id
			selected_expression_name = "远端玩家表情"
			selected_expression_texture = ImageTexture.create_from_image(img)
			_base_uv_min = Vector2.ZERO
			_base_uv_size = Vector2.ONE
			_update_shader_expression()
	else:
		select_expression(expression_id, false)
	if paint_png.size() > 0 and painter != null:
		var paint_image := Image.new()
		if paint_image.load_png_from_buffer(paint_png) == OK:
			painter.set_image(paint_image)