【后端接口】结义值商城：阶梯定价与限购的兑换接口设计

local DISCOUNT = { [30] = 90, [180] = 85, [365] = 75 }
local function discountOf(days)
    local rate = 100
    for d, r in pairs(DISCOUNT) do
        if days >= d and r < rate then rate = r end
    end
    return rate
end
function exchangeBySworn(actor, itemId, baseCost)
    local player = class(actor)
    local days = tonumber(getplayvar(actor, 2, "SWORN_DAYS") or "0")
    local cost = math.floor(baseCost * discountOf(days) / 100)
    local pts = tonumber(getplayvar(actor, 2, "SWORN_PT") or "0")
    if pts < cost then
        sendmsg(actor, 0, "结义值不足，需" .. cost .. "点")
        return
    end
    setplayvar(actor, "HUMAN", "SWORN_PT", pts - cost, 1)
    giveitem(actor, itemId, 1)
    sendmsg(actor, 0, "兑换成功，结义" .. days .. "天，优惠" .. 100 - rate .. "%")
end

local WEEK_LIMIT = 2
local function checkWeeklyCap(actor, itemId)
    local player = class(actor)
    local key = "SWORN_W_" .. os.date("%W") .. itemId
    local cnt = tonumber(getplayvar(actor, 2, key) or "0")
    if cnt >= WEEK_LIMIT then
        sendmsg(actor, 0, "该商品本周限购2件")
        return false
    end
    setplayvar(actor, "HUMAN", key, cnt + 1, 1)
    return true
end