【引擎触发】金币交易：面对面交易与交易确认的引擎实现

function QF.TradeStart(plr, target)
    if plr:DistTo(target) > 3 then return false, "距离过远" end
    if plr.tradeLock or target.tradeLock then return false, "对方正在交易" end
    if plr:InBattle() or target:InBattle() then return false, "战斗中不可交易" end
    plr.tradeLock, target.tradeLock = true, true
    plr.tradeWith, target.tradeWith = target.id, plr.id
    QF_OpenTradeUI(plr, target)
    QF_OpenTradeUI(target, plr)
    return true
end

function QF.TradePut(plr, slot, count)
    local trade = TradeMgr.get(plr.tradeWith, plr.id)
    local item = plr.bag[slot]
    if not item or item.bind then return false, "绑定物品不可交易" end
    plr.bag[slot] = nil
    trade.put[plr.id][slot] = { item = item, n = count }
    TradeMgr.refresh(trade)
    return true
end

function QF.TradeConfirm(plr)
    local trade = TradeMgr.get(plr.tradeWith, plr.id)
    trade.confirmed[plr.id] = true
    if trade.confirmed[trade.a] and trade.confirmed[trade.b] then
        -- 双方确认，原子成交
        local ok = TradeMgr.atomicSettle(trade)
        if ok then
            QF_SendBoth(trade.a, trade.b, "交易成功")
            TradeLog.write("face", trade.a, trade.b, trade.itemList())
        end
        TradeMgr.close(trade)
    else
        QF_SendOther(plr, "对方已锁定交易")
    end
    return true
end