class_name StrongBuffVisual
extends Node2D

const DEFAULT_FRAME_DIRECTORY := "res://assets/ui/strong_buff"

@export var frame_directory := DEFAULT_FRAME_DIRECTORY
@export var frames_per_second := 20.0
@export var center_offset := Vector2(0.0, -38.0)
@export var effect_scale := 0.18

var _active := false
var _frame_index := 0
var _frame_elapsed := 0.0
var _frames: Array[Texture2D] = []
var _sprite: Sprite2D


func _ready() -> void:
	z_index = 1
	_sprite = Sprite2D.new()
	_sprite.name = "StrongBuffEffect"
	_sprite.centered = true
	_sprite.position = center_offset
	_sprite.texture_filter = CanvasItem.TEXTURE_FILTER_NEAREST
	_sprite.visible = false
	add_child(_sprite)
	_load_frames()
	set_active(false)


func _process(delta: float) -> void:
	if not _active or _frames.is_empty():
		return
	_frame_elapsed += delta
	var frame_duration := 1.0 / maxf(1.0, frames_per_second)
	while _frame_elapsed >= frame_duration:
		_frame_elapsed -= frame_duration
		_frame_index = (_frame_index + 1) % _frames.size()
		_sprite.texture = _frames[_frame_index]


func set_active(active: bool) -> void:
	_active = active and not _frames.is_empty()
	visible = _active
	set_process(_active)
	if _sprite != null:
		_sprite.visible = _active
		_sprite.position = center_offset
		_sprite.scale = Vector2.ONE * effect_scale
		if _active and _sprite.texture == null and not _frames.is_empty():
			_sprite.texture = _frames[_frame_index]


func is_active() -> bool:
	return _active


func frame_count() -> int:
	return _frames.size()


func current_effect_scale() -> float:
	return effect_scale


func _load_frames() -> void:
	_frames.clear()
	var dir := DirAccess.open(frame_directory)
	if dir == null:
		return
	# 导出包内贴图在目录列表里显示为 xxx.png.import / xxx.png.remap；
	# 还原原名后 load() 才能命中。编辑器里原图与 .import 同时在列，需去重。
	var files := PackedStringArray()
	dir.list_dir_begin()
	var file_name := dir.get_next()
	while not file_name.is_empty():
		if not dir.current_is_dir():
			var resource_name := file_name.trim_suffix(".import").trim_suffix(".remap")
			if resource_name.ends_with(".png") and not files.has(resource_name):
				files.append(resource_name)
		file_name = dir.get_next()
	dir.list_dir_end()
	files.sort()
	for path_name: String in files:
		var texture := load("%s/%s" % [frame_directory, path_name]) as Texture2D
		if texture != null:
			_frames.append(texture)
	if not _frames.is_empty() and _sprite != null:
		_sprite.texture = _frames[0]