对以下自动化交易EA代码进行优化优化成双向交易既可以sell做空也可以buy做多并且满足以下交易的均线条件：1、以15分钟为一个交易周期15分钟周期K线收盘价处于6日均线、15日均线和30日均线之上开始上穿6日均线开始做多当15分钟周期K线收盘价下穿8日均线指令平仓out交易结束；2、以15分钟为一个交易周期15分钟周期K线收盘价开始处于6日均线、15日均线和30日均线之下并且下穿30日均线的时候

以下是优化后的代码：

//+------------------------------------------------------------------+
//|                  MovingAverageCrossoverEA.mq5                     |
//|                            Created by ChatGPT                      |
//+------------------------------------------------------------------+
#property copyright "Created by ChatGPT"
#property link      "https://www.example.com"
#property version   "1.000"
//---
#include <Trade\PositionInfo.mqh>
#include <Trade\Trade.mqh>
#include <Trade\SymbolInfo.mqh>  
CPositionInfo  m_position;                   // trade position object
CTrade         m_trade;                      // trading object
CSymbolInfo    m_symbol;                     // symbol info object
//--- input parameters
input double   Lots        = 0.5;              // 交易手数
input int      FastMA       = 6;             // 快速均线周期
input int      SlowMA     = 27;             // 慢速均线周期
input ulong    m_magic=42828093;             // 魔术数字
ulong          m_slippage=10;                // 滑点
//---
int         handle_fastMA;                   // 快速均线指标句柄
int         handle_slowMA;                   // 慢速均线指标句柄
//+------------------------------------------------------------------+
//|  Expert initialization function                                  |
//+------------------------------------------------------------------+
int OnInit()
{
    //---
    if(!m_symbol.Name(Symbol())) // 设置交易品种名称
        return(INIT_FAILED);
    RefreshRates();

    string err_text="";
    if(!CheckVolumeValue(Lots,err_text))
    {
        Print(err_text);
        return(INIT_PARAMETERS_INCORRECT);
    }

    //---
    m_trade.SetExpertMagicNumber(m_magic);

    if(IsFillingTypeAllowed(SYMBOL_FILLING_FOK))
        m_trade.SetTypeFilling(ORDER_FILLING_FOK);
    else if(IsFillingTypeAllowed(SYMBOL_FILLING_IOC))
        m_trade.SetTypeFilling(ORDER_FILLING_IOC);
    else
        m_trade.SetTypeFilling(ORDER_FILLING_RETURN);

    m_trade.SetDeviationInPoints(m_slippage);

    //--- 创建快速均线指标句柄
    handle_fastMA = iMA(m_symbol.Name(), Period(), FastMA, 0, MODE_SMA, PRICE_CLOSE);
    //--- 创建慢速均线指标句柄
    handle_slowMA = iMA(m_symbol.Name(), Period(), SlowMA, 0, MODE_SMA, PRICE_CLOSE);

    //--- 检查指标句柄是否创建成功
    if(handle_fastMA == INVALID_HANDLE || handle_slowMA == INVALID_HANDLE)
    {
        Print("Failed to create moving average indicators for the symbol ", m_symbol.Name());
        return(INIT_FAILED);
    }

    return(INIT_SUCCEEDED);
}
//+------------------------------------------------------------------+
//|  Expert deinitialization function                                |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
{
    //---
}
//+------------------------------------------------------------------+
//|  Expert tick function                                            |
//+------------------------------------------------------------------+
void OnTick()
{
    //--- 仅在新K线生成时进行交易
    static datetime PrevBars=0;
    datetime time_0=iTime(0);
    if(time_0==PrevBars)
        return;
    PrevBars=time_0;

    //--- 获取均线值
    double fastMA = iMA(m_symbol.Name(), Period(), FastMA, 0, MODE_SMA, PRICE_CLOSE);
    double slowMA = iMA(m_symbol.Name(), Period(), SlowMA, 0, MODE_SMA, PRICE_CLOSE);  

    //--- 检查当前是否有持仓
    for(int i=PositionsTotal()-1;i>=0;i--)
    {
        if(m_position.SelectByIndex(i))
        {
            if(m_position.Symbol()==m_symbol.Name() && m_position.Magic()==m_magic)
            {
                if(m_position.PositionType()==POSITION_TYPE_BUY && fastMA < slowMA)
                {
                    //--- 卖出持仓
                    m_trade.PositionClose(m_position.Ticket());
                    break;
                }
                else if(m_position.PositionType()==POSITION_TYPE_SELL && fastMA > slowMA)
                {
                    //--- 买入持仓
                    m_trade.PositionClose(m_position.Ticket());
                    break;
                }
            }
        }
    }

    //--- 如果快速均线上穿慢速均线，进行买入交易
    if(fastMA > slowMA)
    {
        if (m_position.PositionType() != POSITION_TYPE_BUY) {
            m_trade.Buy(Lots, m_symbol.Name());
        }
    }
    //--- 如果快速均线下穿慢速均线，进行卖出交易
    else if(fastMA < slowMA)
    {
        if (m_position.PositionType() != POSITION_TYPE_SELL) {
            m_trade.Sell(Lots, m_symbol.Name());
        }
    }

    //--- 如果快速均线下穿慢速均线，进行做空交易
    if(fastMA < slowMA)
    {
        if (m_position.PositionType() != POSITION_TYPE_SELL) {
            m_trade.Sell(Lots, m_symbol.Name());
        }
    }
    //--- 如果快速均线上穿慢速均线，进行平仓交易
    else if(fastMA > slowMA)
    {
        if (m_position.PositionType() != POSITION_TYPE_BUY) {
            m_trade.PositionClose(m_position.Ticket());
        }
    }
    //--- 如果收盘价上穿28日均线，进行平仓交易
    if(fastMA > 28)
    {
        if (m_position.PositionType() != POSITION_TYPE_BUY) {
            m_trade.PositionClose(m_position.Ticket());
        }
    }
    //--- 如果收盘价下穿30日均线，进行做空交易
    else if(fastMA < slowMA)
    {
        if (m_position.PositionType() != POSITION_TYPE_SELL) {
            m_trade.Sell(Lots, m_symbol.Name());
        }
    }
}
//+------------------------------------------------------------------+
//|  刷新交易品种行情数据                                           |
//+------------------------------------------------------------------+
bool RefreshRates(void)
{
    //--- 刷新行情数据
    if(!m_symbol.RefreshRates())
    {
        Print("RefreshRates error");
        return(false);
    }

    //--- 保护返回值不为"零"
    if(m_symbol.Ask()==0 || m_symbol.Bid()==0)
        return(false);

    return(true);
}
//+------------------------------------------------------------------+
//|  检查交易手数的正确性                                           |
//+------------------------------------------------------------------+
bool CheckVolumeValue(double volume, string &error_description)
{
    //--- 最小允许交易手数
    double min_volume = m_symbol.LotsMin();
    if(volume < min_volume)
    {
        error_description = StringFormat("Volume is less than the minimal allowed SYMBOL_VOLUME_MIN=%.2f", min_volume);
        return(false);
    }

    //--- 最大允许交易手数
    double max_volume = m_symbol.LotsMax();
    if(volume > max_volume)
    {
        error_description = StringFormat("Volume is greater than the maximal allowed SYMBOL_VOLUME_MAX=%.2f", max_volume);
        return(false);
    }

    //--- 获取交易手数变动的最小步长
    double volume_step = m_symbol.LotsStep();
    int ratio = (int)MathRound(volume / volume_step);
    if(MathAbs(ratio * volume_step - volume) > 0.0000001)
    {
        error_description = StringFormat("Volume is not a multiple of the minimal step SYMBOL_VOLUME_STEP=%.2f, the closest correct volume is %.2f",
                                     volume_step,ratio * volume_step);
        return(false);
    }
    error_description = "Correct volume value";
    return(true);
}
//+------------------------------------------------------------------+ 
//|  检查指定的成交模式是否允许                                     | 
//+------------------------------------------------------------------+ 
bool IsFillingTypeAllowed(int fill_type)
{
    int filling = m_symbol.TradeFillFlags();
    return((filling & fill_type) == fill_type);
}
//+------------------------------------------------------------------+ 
//|  获取指定柱子的时间                                              | 
//+------------------------------------------------------------------+ 
datetime iTime(const int index, string symbol=NULL, ENUM_TIMEFRAMES timeframe=PERIOD_CURRENT)
{
    if(symbol == NULL)
        symbol = m_symbol.Name();
    if(timeframe == 0)
        timeframe = Period();
    datetime Time[1];
    datetime time =