CopyRates of higher timeframe in OnCalculate function of a custom indicator

Hello. I want always have rates of daily timeframe in an array to use it in my custom indicator.

I write it in this way to copy all daily rates in first run, and update only last day's rate in every next OnCalculate() call. But it seems this is not the correct way. Can anyone help me?

//+------------------------------------------------------------------+
//| 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[])
  {
//---
   MqlRates Rates[];
   ArraySetAsSeries(Rates, true);
   int Limit;
   if(prev_calculated == 0)
     {
      Limit = rates_total - 1;
      CopyRates(Symbol(), PERIOD_D1, time[Limit], time[0], Rates);
     }
   else
     {
      Limit = rates_total - prev_calculated;
      CopyRates(Symbol(), PERIOD_D1, 0, 1, Rates);
     }

//--- Main Loop
   for(int i = Limit; i >= 0; i--)
        {

        }