extends Control

@onready var weapon_scene: PackedScene = preload("res://scene/ui/item/weapon_item.tscn")

var item_layout_offset_x: int        = 32
var item_layout_offset_y: int        = 16
var weapon_item_list: Array[Variant] = []
var weapon_list: Array
var weapon_index: int
var weapon_index_dir: int
var weapon_index_rate: float


func _process(delta) -> void:
	if weapon_index_dir:
		item_lerp(weapon_index_dir, weapon_index_rate)
		return
	item_lerp(weapon_index_dir, 1)


func on_weapon_list_changed(list: Array): 
	weapon_list = list
	init_weapon_item()


func on_weapon_index_changed(index: int): 
	weapon_index = index


func on_weapon_index_change_rate_changed(rate: float): 
	weapon_index_rate = rate


func on_weapon_index_change_dir_changed(dir: int) -> void:
	weapon_index_dir = dir
	if not weapon_index_dir:
		return
	else:
		if dir > 0:
			push_back()
			pop_front()
		else:
			push_front()
			pop_back()


func append(): weapon_item_list.append(create_weapon_item(len(weapon_item_list)-2+weapon_index_dir))


func push_front(): weapon_item_list.push_front(create_weapon_item(-2+weapon_index_dir))


func push_back(): weapon_item_list.push_back(create_weapon_item(2+weapon_index_dir))


func pop_front(): remove_child(weapon_item_list.pop_front())


func pop_back(): remove_child(weapon_item_list.pop_back())

func init_weapon_item():
	for item in weapon_item_list:
		remove_child(item)
	weapon_item_list.clear()
	for i in range(5): append()

func create_weapon_item(offset: int)->WeaponItemSub:
	var weapon_count: int              = len(weapon_list)
	var index: int                     = ((weapon_index + offset) % weapon_count + weapon_count) % weapon_count
	var weapon_item_sub: WeaponItemSub = weapon_scene.instantiate() as WeaponItemSub
	var weapon_cfg: WeaponCfg          = weapon_list[index] as WeaponCfg
	add_child(weapon_item_sub)
	weapon_item_sub.init(weapon_cfg.icon)
	return weapon_item_sub


func item_lerp(dir: int, rate: float):
	for i in range(len(weapon_item_list)):
		var item: WeaponItemSub = weapon_item_list[i] as WeaponItemSub
		var target_index        = i-2
		var index               = target_index+dir
		var pos_from: Vector2   = get_item_pos(index)
		var pos_to: Vector2     = get_item_pos(target_index)
		var alpha_from: int     = 1 if abs(index)<=1 else 0
		var alpha_to: int       = 1 if abs(target_index)<=1 else 0
		item.position = lerp(pos_from, pos_to, rate)
		item.update_alpha(alpha_from, alpha_to, rate)


func get_item_pos(offset: int) -> Vector2:
	return Vector2(item_layout_offset_x*offset, item_layout_offset_y if offset else 0)