玩家御守：限时护符的减伤守护

local function buyCharm(actor)
    local today = os.date("%Y%m%d")
    if getplayvar(actor, "charmDay") == today then
        sendmsg(actor, 1, "每日限购一枚")
        return
    end
    if (getplayvar(actor, "GOLD") or 0) < 800 then
        sendmsg(actor, 1, "金币不足 800")
        return
    end
    setplayvar(actor, "GOLD",
        (getplayvar(actor, "GOLD") or 0) - 800)
    setplayvar(actor, "charmDay", today)
    setplayvar(actor, "charmEnd", os.time() + 3600)
    sendmsg(actor, 1, "御守生效 1 小时，减伤 30%")
end

local function charmBreak(actor)
    if (getplayvar(actor, "charmEnd") or 0)
        > os.time() then
        setplayvar(actor, "charmEnd", 0)
        sendmsg(actor, 1, "主动攻击，御守碎裂失效")
    end
end