【后端接口】好友助战：援护作战与感谢回馈

---好友助战：邀请好友入场援护
function Assist.call(actor, friendName)
    local player = class(actor)
    if not player then return false end
    -- 每日 3 次的助战请求上限
    local dayKey = "AssistCall_" .. os.date("%Y%m%d")
    local n = tonumber(getplayvar(actor, 2, dayKey)) or 0
    if n >= 3 then
        sendmsg(actor, 1, "今日助战请求已达上限（3 次）")
        return false
    end
    setplayvar(actor, "HUMAN", dayKey, n + 1, 0)
    -- 好友响应：30 秒的确认窗口
    sendmsg(friendName, 1, actor ..
        " 请求助战！回复「1」30 秒内传送支援")
    setplayvar(getplayerbyname(friendName), "HUMAN",
        "AssistFrom", actor, 0)
    setplayvar(getplayerbyname(friendName), "HUMAN",
        "AssistExpire", os.time() + 30, 0)
    return true
end

---战后感谢：感谢信与亲密度的双重回馈
function Assist.thanks(actor, friendName)
    if not checkitemw(actor, "感谢信", 1) then
        sendmsg(actor, 1, "缺少感谢信（打宝掉落）")
        return false
    end
    takeitem(actor, "感谢信", 1, 0, "助战感谢")
    sendmail(friendName, 8016, "来自战友的感谢",
        actor .. " 本次的援护作战支持", "感谢回礼|1")
    local it = tonumber(getplayvar(friendName, 2,
        "Intimacy_" .. actor)) or 0
    setplayvar(friendName, "HUMAN",
        "Intimacy_" .. actor, it + 20, 1)
    sendmsg(actor, 1, "感谢已送达，好友亲密度 +20")
    return true
end