persistable sclass TradingCandleMaker {
  settable double candleLength = 1; // in minutes
  
  *(double *candleLength) {}
  
  new L<TradingCandle> candles;
  
  TradingCandle currentCandle() { ret last(candles); }  
  
  void add(double price, long timestamp) {
    if (currentCandle() != null)
      currentCandle().addValue(price, new Timestamp(timestamp));
      
    if (needNewCandle(timestamp)) {
      candles.add(new TradingCandle);
      currentCandle().addValue(price, new Timestamp(timestamp));
    }
  }
  
  void addTickerSequence(TickerSequence ts) {
    int n = l(ts);
    for i to n:
      add(ts.prices.get(i), ts.timestamps.get(i));
  }
  
  bool needNewCandle(long timestamp) {
    ret empty(candles)
      || timestamp >= currentCandle().startTime.plusSeconds(candleLength*60).unixDate();
  }
}