【进阶实战】装备交易行的挂单撤销：窗口期与撤单税封装

local orders = {}
local function cancelOrder(actor, orderId)
    actor = getplayerbyname(actor)
    local o = orders[orderId]
    if o == nil then
        sendmsg(actor, 1, "挂单不存在或已成交。")
        return false
    end
    if o.owner ~= tostring(actor) then
        sendmsg(actor, 1, "只能撤销自己的挂单。")
        return false
    end
    if o.sold then
        sendmsg(actor, 1, "该单已成交，无法撤销。")
        return false
    end
    local now = os.time()
    local tax = 0
    if now - o.listTime > 600 then
        tax = math.max(math.floor(o.price * 0.01), 1000)
        if not takeitem(actor, "金币", tax, 0, "撤单税") then
            sendmsg(actor, 1, "撤单税 " .. tax .. " 金币不足，无法撤销。")
            return false
        end
    end
    o.sold = true
    orders[orderId] = nil
    giveitem(actor, o.item, 1, o.bind, "撤单回流")
    sendmsg(actor, 1, o.item .. " 已撤单回流，收费 " .. tax .. " 金币。")
    return true
end

local function listOrder(actor, item, price, bind)
    actor = getplayerbyname(actor)
    local id = "OD" .. os.time()
    orders[id] = { owner = tostring(actor), item = item,
        price = price, bind = bind, listTime = os.time(), sold = false }
    sendmsg(actor, 1, item .. " 已挂单，10 分钟内免费可撤。")
    return id
end