【玩法设计】交易行指导价：价格指数与挂牌参考的规则设计

local deals = {}
local function updateIndex(itemName, price)
    local now = os.time()
    deals[itemName] = deals[itemName] or {}
    table.insert(deals[itemName], { p = price, t = now })
    local list, sum, wsum = deals[itemName], 0, 0
    for j = #list, 1, -1 do
        local age = now - list[j].t
        if age > 604800 then
            table.remove(list, j)
        else
            local w = 7 - math.floor(age / 86400)
            sum = sum + list[j].p * w
            wsum = wsum + w
        end
    end
    return wsum > 0 and math.floor(sum / wsum) or 0
end

local function tagListing(itemName, price, index)
    local tag = ""
    if index > 0 and price > index * 5 then
        tag = "【远超参考价】"
    elseif index > 0 and price < index / 5 then
        tag = "【疑似错价】"
    end
    return tag .. itemName .. " 指导价" .. index
end