丹药炼制：药效时段与抗性递减

-- 错误：来一颗叠一层，无时限无递减
function usePill(p, kind)
    grantBuff(p, kind, 1)
end

local function usePill(p, kind)
    local now = os.time()
    local last = tonumber(getplayvar(p, "pill_" .. kind) or "0")
    local cntKey = "pill_" .. kind .. "_n"
    local n = tonumber(getplayvar(p, cntKey) or "0")
    if now - last < 1800 and n >= 2 then
        sendmsg(p, 1, "药力已抗，稍后再服")
        return
    end
    if now - last < 1800 then
        setplayvar(p, cntKey, n + 1)
        grantBuff(p, kind, 0.5)
        return
    end
    setplayvar(p, "pill_" .. kind, now)
    setplayvar(p, cntKey, 1)
    grantBuff(p, kind, 1)
end