TouhouGD/script/ui/hud/weapon_item.gd

extends Control

@onready var weapon_scene = 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 = []
var weapon_list: Array
var weapon_index: int
var weapon_index_dir: int
var weapon_index_rate: float
var hide_duration: float


func _process(delta):
    if not visible:
        return
    if weapon_index_dir:
        item_lerp(weapon_index_dir, weapon_index_rate)
        hide_duration = Setting.weapon_hide_duration
        return
    item_lerp(weapon_index_dir, 1)
    hide_duration -= delta
    if hide_duration <= 0:
        for item in weapon_item_list:
            remove_child(item)
        weapon_item_list.clear()
        visible = false


func on_weapon_list_changed(list: Array): weapon_list = list


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):
    weapon_index_dir = dir
    if not weapon_index_dir:
        return
    if not visible:
        visible = true
        for i in range(5): append()
    else:
        if dir > 0:
            push_back()
            pop_front()
        else:
            push_front()
            pop_back()
    hide_duration = Setting.weapon_hide_duration


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 create_weapon_item(offset: int)->WeaponItemSub:
    var weapon_count    = len(weapon_list)
    var index           = ((weapon_index + offset) % weapon_count + weapon_count) % weapon_count
    var weapon_item_sub = weapon_scene.instantiate() as WeaponItemSub
    var weapon_cfg      = 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         = weapon_item_list[i] as WeaponItemSub
        var target_index = i-2
        var index        = target_index+dir
        var pos_from     = get_item_pos(index)
        var pos_to       = get_item_pos(target_index)
        var alpha_from   = 1 if abs(index)<=1 else 0
        var alpha_to     = 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):
    return Vector2(item_layout_offset_x*offset, item_layout_offset_y if offset else 0)