//+------------------------------------------------------------------+
//|                                        OHLC_Export_Script.mq5     |
//| Export all available OHLC bars to CSV                             |
//| Output: MQL5\Files\<Symbol>_<TF>_OHLC.csv                        |
//+------------------------------------------------------------------+
#property strict
#property script_show_inputs

input string FileName = ""; // Output filename (empty = auto: Symbol_TF_OHLC.csv)

void OnStart()
  {
   string sym = _Symbol;
   ENUM_TIMEFRAMES tf = _Period;

   if(TerminalInfoInteger(TERMINAL_CONNECTED) == 0)
     { Print("Terminal not connected to server. Cannot download."); return; }

   // Trigger download and wait for data sync
   Print("Requesting full history for ", sym, " ", EnumToString(tf), "...");
   int prev = 0, cur = Bars(sym, tf);
   int retries = 0;
   while(cur < 10 || cur != prev)
     {
      prev = cur;
      Sleep(1000);
      cur = Bars(sym, tf);
      retries++;
      if(retries % 5 == 0) PrintFormat("  Downloaded %d bars so far...", cur);
      if(retries > 60) { Print("Timeout waiting for data. Exporting what's available."); break; }
     }

   if(cur <= 0) { Print("No bars available for ", sym); return; }
   PrintFormat("Total bars available: %d", cur);

   string fn = (FileName != "") ? FileName : sym + "_" + EnumToString(tf) + "_OHLC.csv";
   int h = FileOpen(fn, FILE_WRITE|FILE_CSV|FILE_ANSI, ',');
   if(h == INVALID_HANDLE) { Print("Cannot create file: ", fn); return; }

   FileWrite(h, "Timestamp", "Open", "High", "Low", "Close", "TickVolume", "Spread");

   MqlRates r[];
   ArraySetAsSeries(r, true);
   int copied = 0, chunk = 5000;
   for(int start = 0; start < cur; start += chunk)
     {
      int toCopy = MathMin(chunk, cur - start);
      if(CopyRates(sym, tf, start, toCopy, r) <= 0) break;
      copied += toCopy;
      for(int i = 0; i < toCopy; i++)
         FileWrite(h, TimeToString(r[i].time, TIME_DATE|TIME_MINUTES|TIME_SECONDS),
                   DoubleToString(r[i].open,  (int)SymbolInfoInteger(sym, SYMBOL_DIGITS)),
                   DoubleToString(r[i].high,  (int)SymbolInfoInteger(sym, SYMBOL_DIGITS)),
                   DoubleToString(r[i].low,   (int)SymbolInfoInteger(sym, SYMBOL_DIGITS)),
                   DoubleToString(r[i].close, (int)SymbolInfoInteger(sym, SYMBOL_DIGITS)),
                   (long)r[i].tick_volume, (int)r[i].spread);
     }

   FileClose(h);
   PrintFormat("Exported %d bars to %s (MQL5\\Files\\%s)", copied, fn, fn);
  }
//+------------------------------------------------------------------+