# inventory_sort_system.gd —— Metin2 40250 多页背包智能自动整理与堆叠合并 1:1
# 对照 40250 服务端 char_item.cpp, uiinventory.py, item.cpp
class_name InventorySortSystem
extends RefCounted

signal inventory_sorted(total_items: int, merged_stacks: int)
signal page_switched(new_page: int)

const PAGE_SIZE := 45
const TOTAL_PAGES := 2
const TOTAL_SLOTS := 90 # 45 x 2
const MAX_STACK_LIMIT := 200

# 排序优先级分类
enum ItemCategory {
	WEAPON = 1,     # 武器
	ARMOR = 2,      # 铠甲防具
	JEWELRY = 3,    # 饰品首饰
	CONSUMABLE = 4, # 药水与消耗品
	MATERIAL = 5,   # 强化升阶材料
	CHEST_KEY = 6,  # 宝箱与钥匙
	OTHER = 7       # 其他
}

var current_page: int = 0

# 切换当前显示背包页 (0 或 1)
func switch_page(page_idx: int) -> Dictionary:
	if page_idx < 0 or page_idx >= TOTAL_PAGES:
		return {"ok": false, "reason": "INVALID_PAGE", "msg": "无效的背包页码！"}

	current_page = page_idx
	page_switched.emit(page_idx)

	return {
		"ok": true,
		"page": page_idx,
		"slot_start": page_idx * PAGE_SIZE,
		"slot_end": (page_idx + 1) * PAGE_SIZE - 1
	}

# 获取物品所属排序大类
static func get_item_category(item: Dictionary) -> int:
	var it_type: String = item.get("item_type", "")
	match it_type:
		"weapon":
			return ItemCategory.WEAPON
		"armor", "shield", "helmet":
			return ItemCategory.ARMOR
		"jewelry", "necklace", "earrings", "bracelet", "shoes", "belt":
			return ItemCategory.JEWELRY
		"potion", "consumable", "dew", "elixir":
			return ItemCategory.CONSUMABLE
		"material", "fragment", "scroll":
			return ItemCategory.MATERIAL
		"chest", "key":
			return ItemCategory.CHEST_KEY
		_:
			# 根据 vnum 范围与特征推断
			var vnum: int = int(item.get("vnum", 0))
			if vnum < 3000 and vnum >= 10:
				return ItemCategory.WEAPON
			elif vnum >= 11000 and vnum < 13200:
				return ItemCategory.ARMOR
			elif (vnum >= 27000 and vnum < 28000) or (vnum >= 50800 and vnum < 50900) or (vnum >= 72700 and vnum < 72800):
				return ItemCategory.CONSUMABLE
			elif (vnum >= 50000 and vnum < 50200) or (vnum >= 30000 and vnum < 30400):
				return ItemCategory.CHEST_KEY
			elif vnum >= 71000 and vnum < 72000:
				return ItemCategory.MATERIAL
			return ItemCategory.OTHER

# 判定物品是否可堆叠
static func is_item_stackable(item: Dictionary) -> bool:
	if item.get("is_stackable", false):
		return true
	var it_type: String = item.get("item_type", "")
	if ["potion", "consumable", "dew", "elixir", "material", "fragment", "scroll", "arrow"].has(it_type):
		return true
	var cnt: int = int(item.get("count", 1))
	return cnt > 1

# 自动合并碎片堆叠 (Auto-Stack Merge)
func merge_stacks(inventory: Array) -> int:
	var merged_count := 0

	for i in range(inventory.size()):
		var base = inventory[i]
		if base == null or not is_item_stackable(base):
			continue

		var b_vnum: int = int(base.get("vnum", 0))
		var b_count: int = int(base.get("count", 1))
		if b_count >= MAX_STACK_LIMIT:
			continue

		for j in range(i + 1, inventory.size()):
			var other = inventory[j]
			if other == null or int(other.get("vnum", 0)) != b_vnum:
				continue

			var o_count: int = int(other.get("count", 1))
			var space := MAX_STACK_LIMIT - b_count

			if o_count <= space:
				b_count += o_count
				base["count"] = b_count
				inventory[j] = null
				merged_count += 1
			else:
				b_count = MAX_STACK_LIMIT
				base["count"] = MAX_STACK_LIMIT
				other["count"] = o_count - space
				merged_count += 1
				break

	return merged_count

# 一键智能整理背包 (堆叠合并 + 分类前置紧凑排序)
func sort_inventory(inventory: Array) -> Dictionary:
	# 1. 先进行碎片堆叠合并
	var merged := merge_stacks(inventory)

	# 2. 收集所有有效物品并打上排序权重标签
	var items_to_sort: Array = []
	for i in range(inventory.size()):
		var it = inventory[i]
		if it != null:
			var cat := get_item_category(it)
			var vnum: int = int(it.get("vnum", 0))
			var level: int = int(it.get("level", 0))
			items_to_sort.append({
				"item": it,
				"category": cat,
				"vnum": vnum,
				"level": level
			})

	# 3. 排序比较器：类别升序 (1~7)，同类内 vnum 升序/降序排列
	items_to_sort.sort_custom(func(a: Dictionary, b: Dictionary) -> bool:
		if a["category"] != b["category"]:
			return a["category"] < b["category"]
		if a["vnum"] != b["vnum"]:
			return a["vnum"] < b["vnum"]
		return int(a["item"].get("count", 1)) > int(b["item"].get("count", 1))
	)

	# 4. 紧凑回填背包并清空末尾
	var total_items := items_to_sort.size()
	for i in range(inventory.size()):
		if i < total_items:
			inventory[i] = items_to_sort[i]["item"]
		else:
			inventory[i] = null

	inventory_sorted.emit(total_items, merged)

	return {
		"ok": true,
		"total_items": total_items,
		"merged_stacks": merged,
		"msg": "背包整理完成！共归纳 %d 件物品，合并 %d 处堆叠。" % [total_items, merged]
	}