mtgodot-poc/project/mail_system.gd

# mail_system.gd —— Metin2 40250 游戏内邮箱系统与附件寄送提取 1:1
# 对照 40250 服务端 mailbox.cpp, input_db.cpp, uimailbox.py
class_name MailSystem
extends RefCounted

signal mail_sent(mail_id: int, sender: String, recipient: String)
signal mail_received(mail_id: int, recipient: String, title: String)
signal unread_count_changed(recipient: String, count: int)
signal attachment_claimed(mail_id: int)

const POSTAGE_FEE := 1000                # 寄件固定邮资 1000 金币
const MAX_TITLE_LENGTH := 25             # 标题最长字符
const MAX_BODY_LENGTH := 100             # 正文最长字符
const MAIL_EXPIRATION_SECONDS := 2592000.0 # 30 天有效期 (30 * 86400)

var mails: Array = []
var next_mail_id: int = 1

# 寄送邮件
func send_mail(
	sender: String,
	recipient: String,
	title: String,
	body: String,
	player_data: Dictionary,
	inventory: Array,
	attach_slot: int = -1,
	attach_gold: int = 0,
	current_time: float = 0.0
) -> Dictionary:
	if recipient.strip_edges().is_empty():
		return {"ok": false, "reason": "EMPTY_RECIPIENT", "msg": "收件人不能为空！"}

	if title.length() > MAX_TITLE_LENGTH:
		return {"ok": false, "reason": "TITLE_TOO_LONG", "msg": "邮件标题过长！"}

	if body.length() > MAX_BODY_LENGTH:
		return {"ok": false, "reason": "BODY_TOO_LONG", "msg": "邮件正文过长！"}

	if attach_gold < 0:
		return {"ok": false, "reason": "INVALID_GOLD", "msg": "附加金币数额无效！"}

	# 检查玩家金币 (邮资 1000 + 附加金币)
	var total_gold_cost := POSTAGE_FEE + attach_gold
	var player_gold: int = int(player_data.get("gold", 0))
	if player_gold < total_gold_cost:
		return {
			"ok": false,
			"reason": "INSUFFICIENT_YANG",
			"required": total_gold_cost,
			"current": player_gold,
			"msg": "金币不足以支付邮资与附件！需要 %d 金币。" % total_gold_cost
		}

	# 检查附加物品
	var attached_item = null
	if attach_slot >= 0:
		if attach_slot >= inventory.size() or inventory[attach_slot] == null:
			return {"ok": false, "reason": "INVALID_ATTACH_ITEM", "msg": "所选格子没有物品！"}
		var item = inventory[attach_slot]
		if item.get("is_locked", false):
			return {"ok": false, "reason": "ITEM_LOCKED", "msg": "已加锁的物品无法邮寄！"}
		attached_item = item.duplicate(true)
		inventory[attach_slot] = null

	# 扣除金币
	player_data["gold"] = player_gold - total_gold_cost

	# 创建邮件
	var mail_id := next_mail_id
	next_mail_id += 1

	var mail_entry: Dictionary = {
		"id": mail_id,
		"sender": sender,
		"recipient": recipient,
		"title": title,
		"body": body,
		"send_time": current_time,
		"expire_time": current_time + MAIL_EXPIRATION_SECONDS,
		"is_read": false,
		"attached_gold": attach_gold,
		"attached_item": attached_item,
		"is_gold_claimed": (attach_gold == 0),
		"is_item_claimed": (attached_item == null)
	}

	mails.append(mail_entry)

	mail_sent.emit(mail_id, sender, recipient)
	mail_received.emit(mail_id, recipient, title)
	unread_count_changed.emit(recipient, get_unread_count(recipient))

	return {
		"ok": true,
		"mail_id": mail_id,
		"msg": "邮件已成功寄出！"
	}

# 获取指定收件人的收件箱
func get_inbox(recipient: String) -> Array:
	var list: Array = []
	for m in mails:
		if m["recipient"] == recipient:
			list.append(m)
	return list

# 查阅邮件
func read_mail(mail_id: int, current_player: String) -> Dictionary:
	for m in mails:
		if m["id"] == mail_id and m["recipient"] == current_player:
			if not m["is_read"]:
				m["is_read"] = true
				unread_count_changed.emit(current_player, get_unread_count(current_player))
			return {"ok": true, "mail": m.duplicate(true)}
	return {"ok": false, "reason": "MAIL_NOT_FOUND", "msg": "未找到该邮件！"}

# 提取邮件附件 (金币与物品)
func claim_attachments(
	mail_id: int,
	current_player: String,
	player_data: Dictionary,
	inventory: Array
) -> Dictionary:
	var target_mail = null
	for m in mails:
		if m["id"] == mail_id and m["recipient"] == current_player:
			target_mail = m
			break

	if target_mail == null:
		return {"ok": false, "reason": "MAIL_NOT_FOUND", "msg": "未找到指定邮件！"}

	var claimed_gold: int = 0
	var claimed_item = null

	# 提取金币
	if not target_mail["is_gold_claimed"] and target_mail["attached_gold"] > 0:
		claimed_gold = target_mail["attached_gold"]
		player_data["gold"] = int(player_data.get("gold", 0)) + claimed_gold
		target_mail["attached_gold"] = 0
		target_mail["is_gold_claimed"] = true

	# 提取物品
	if not target_mail["is_item_claimed"] and target_mail["attached_item"] != null:
		# 寻找背包空位
		var empty_slot := -1
		for i in range(inventory.size()):
			if inventory[i] == null:
				empty_slot = i
				break

		if empty_slot == -1:
			return {
				"ok": false,
				"reason": "INVENTORY_FULL",
				"claimed_gold": claimed_gold,
				"msg": "背包已满，无法提取物品附件！"
			}

		claimed_item = target_mail["attached_item"].duplicate(true)
		inventory[empty_slot] = claimed_item
		target_mail["attached_item"] = null
		target_mail["is_item_claimed"] = true

	attachment_claimed.emit(mail_id)

	return {
		"ok": true,
		"claimed_gold": claimed_gold,
		"claimed_item": claimed_item,
		"msg": "附件提取成功！"
	}

# 删除邮件
func delete_mail(mail_id: int, current_player: String) -> Dictionary:
	for i in range(mails.size()):
		var m = mails[i]
		if m["id"] == mail_id and m["recipient"] == current_player:
			# 检查是否有未提取的附件
			if not m["is_gold_claimed"] or not m["is_item_claimed"]:
				return {
					"ok": false,
					"reason": "HAS_UNCLAIMED_ATTACHMENTS",
					"msg": "邮件内包含尚未提取的附件，无法删除！"
				}

			mails.remove_at(i)
			unread_count_changed.emit(current_player, get_unread_count(current_player))
			return {"ok": true, "msg": "邮件已删除。"}

	return {"ok": false, "reason": "MAIL_NOT_FOUND", "msg": "未找到指定邮件！"}

# 获取未读邮件数量
func get_unread_count(recipient: String) -> int:
	var cnt := 0
	for m in mails:
		if m["recipient"] == recipient and not m["is_read"]:
			cnt += 1
	return cnt

# 过期邮件清理 (30天自动销毁)
func cleanup_expired_mails(current_time: float) -> int:
	var removed := 0
	var i := mails.size() - 1
	while i >= 0:
		if current_time >= mails[i]["expire_time"]:
			var recipient: String = mails[i]["recipient"]
			mails.remove_at(i)
			removed += 1
			unread_count_changed.emit(recipient, get_unread_count(recipient))
		i -= 1
	return removed