とりあえずロジックのサインを確認するテストインジケーター

//+------------------------------------------------------------------+
//|                                                ArrowTemplate.mq4 |
//|                                  Copyright 2025, MetaQuotes Ltd. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2025, MetaQuotes Ltd."
#property link      "https://www.mql5.com"
#property version   "1.00"
#property strict
#property indicator_chart_window
#property indicator_buffers 3
#property indicator_color1 Turquoise
#property indicator_color2 Crimson
#property indicator_color3 Khaki
double _Buy[];
double _Sell[];
double _Close[];

//--- indicator parameters
input int    InpBandsPeriod=20;      // Bands Period
input double InpBandsDeviations=2.0; // Bands Deviations
input int    InpBandsShift=12;        // Bands Shift
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
{
    SetIndexBuffer(0,_Buy);
    SetIndexBuffer(1,_Sell);
    SetIndexBuffer(2,_Close);
    SetIndexStyle(0,DRAW_ARROW,0,2);
    SetIndexStyle(1,DRAW_ARROW,0,2);
    SetIndexStyle(2,DRAW_ARROW,0,3);
    SetIndexArrow(0, 236);
    SetIndexArrow(1, 238);
    SetIndexArrow(2, 251);
    return(INIT_SUCCEEDED);
}
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
{
    int limit = Bars - IndicatorCounted() - 1;
    for (int i = 0; i < limit; i++)
    {
        double upper0=iBands(NULL,0,InpBandsPeriod,InpBandsDeviations,InpBandsShift,PRICE_CLOSE,MODE_UPPER,i);
        double midle0=iBands(NULL,0,InpBandsPeriod,InpBandsDeviations,InpBandsShift,PRICE_CLOSE,MODE_MAIN,i);
        double lower0=iBands(NULL,0,InpBandsPeriod,InpBandsDeviations,InpBandsShift,PRICE_CLOSE,MODE_LOWER,i);
        double upper1=iBands(NULL,0,InpBandsPeriod,InpBandsDeviations,InpBandsShift,PRICE_CLOSE,MODE_UPPER,i+1);
        double midle1=iBands(NULL,0,InpBandsPeriod,InpBandsDeviations,InpBandsShift,PRICE_CLOSE,MODE_MAIN,i+1);
        double lower1=iBands(NULL,0,InpBandsPeriod,InpBandsDeviations,InpBandsShift,PRICE_CLOSE,MODE_LOWER,i+1);
        
        //買い条件
        if(Close[i]>upper0 && Close[i+1]<upper1)
        {
            _Buy[i]=Close[i];
        }
        //売り条件
        else if(Close[i]<lower0 && Close[i+1]>lower1)
        {
            _Sell[i]=Close[i];
        }
        //決済損切り条件
        else if((Open[i]>midle0 && Close[i]<midle0) || (Open[i]<midle0 && Close[i]>midle0) )
        {
            _Close[i]=Close[i];
        }

            
    }
    return(rates_total);
}