[HandlerName("BBands")]
    [HandlerCategory("vvBands&Channels")]
    public class BBands : IDouble2DoubleHandler
    {
        [HandlerParameter(true, "20", Min = "0", Max = "50", Step = "1")]
        public int BandsPeriod { get; set; }
        [HandlerParameter(true, "2", Min = "0.5", Max = "3", Step = "0.5")]
        public double BandsDeviation { get; set; }
        [HandlerParameter(true, "0", Min = "0", Max = "2", Step = "1")]
        //[HandlerParameter(true, "0", NotOptimized = true)]
        public int BandMode { get; set; } // 0-main, 1-top band, 2-low band


        public static IList<double> GenBBands(IList<double> src, int _BandsPeriod, double _BandsDeviation, int _BandMode)
        {
            var bars = src.Count;
            //
            var Close = src;
            //---- buffers
            //var MovingBuffer = new double[bars];
            var UpperBuffer  = new double[bars];
            var LowerBuffer  = new double[bars];
            //
            double deviation, sum, oldval, newres;
            //
            var MovingBuffer = SMA.GenSMA(src, _BandsPeriod);
            //
            for (int i = _BandsPeriod; i < bars; i++)
            {
                sum = 0.0;
                int k = i - _BandsPeriod + 1;
                oldval = MovingBuffer[i];
                while (k <= i)
                {
                    newres = Close[k] - oldval;
                    sum += newres * newres;
                    k++;
                }
                deviation = _BandsDeviation * Math.Sqrt(sum / _BandsPeriod);
                UpperBuffer[i] = oldval + deviation;
                LowerBuffer[i] = oldval - deviation;
            }
            //
            if (_BandMode == 1) return UpperBuffer;
            if (_BandMode == 2) return LowerBuffer;
            return MovingBuffer;
        }
       
        // то же, что и BBands, но с использованием iBBands
        public static IList<double> GenBBands2(IList<double> src, int _BandsPeriod, double _BandsDeviation, int _BandMode)
                {
                    var BBBuffer = new double[src.Count];
                    //
                    for (int i = 0; i < src.Count; i++)
                    {
                        double bb = iBBands(src, _BandsPeriod, _BandsDeviation, _BandMode, i);
                        BBBuffer[i] = bb;
                    }
                    //
                    return BBBuffer;
                }
       
        public static double iBBands(IList<double> src, int BandsPeriod, double BandsDeviation, int _BandMode, int barNum)
                {
                    if (barNum < BandsPeriod) BandsPeriod = barNum;
                    //
                    double deviation, sum, oldval, newres;
                    //
                    double ma = SMA.iSMA(src, BandsPeriod, barNum);
                    //
                    sum = 0.0;
                    int k = barNum - BandsPeriod + 1;
                    oldval = ma;
                    while (k <= barNum)
                    {
                         newres = src[k] - oldval;
                         sum += newres * newres;
                         k++;
                    }
                    deviation = BandsDeviation * Math.Sqrt(sum / BandsPeriod);
                    //
                    if (_BandMode == 1) return oldval + deviation;
                    if (_BandMode == 2) return oldval - deviation;
                    return oldval;
                }
         

        public IList<double> Execute(IList<double> src)
        {
            return GenBBands(src, BandsPeriod, BandsDeviation, BandMode);
        }

    }