persistable sclass SMAIndicator extends CandleBasedIndicator<Double> {
  // The SMA calculator
  settable SmoothedMovingAverage sma;
  
  // SMA values collected as ticker
  gettable TickerSequence history = new TickerSequence("SMA");
  
  // SMA value
  double value = Double.NaN;
  
  Double value() { ret value; }

  *(int *length) {}

  {
    length = 7;
    
    onCandleAdded((IVF1<TradingCandle>) candle -> {
      if (sma == null) sma = new SmoothedMovingAverage(length);
      
      sma.add(candle.close());
      value = sma.complete() ? sma! : Double.NaN;
      if (!isNaN(value)) {
        long time = candle.endTime().toLong();
        history?.addIfPriceChanged(value, time);
      }
    });
  }
  
  TickerSequence asTicker(L<TradingCandle> candles) {
    feed(candles);
    ret history;
  }
  
  void reset :: after {
    resetFields(this, "value history");
    sma?.reset();
  }
}