using NAudio.Dsp;

using System;

namespace AudioVisualizer
{
    /*
    *This class is not created by me(Stone_Red)
    *I forgot who mad this class if i find the source of this class i will credit the original creator
    */
    internal class SampleAggregator
    {
        // FFT
        public event EventHandler<FftEventArgs> FftCalculated;
        public bool PerformFFT { get; set; }
        private readonly Complex[] fftBuffer;
        private readonly FftEventArgs fftArgs;
        private int fftPos;
        private readonly int fftLength;
        private readonly int m;

        public SampleAggregator(int fftLength)
        {
            if (!IsPowerOfTwo(fftLength))
            {
                throw new ArgumentException("FFT Length must be a power of two");
            }
            m = (int)Math.Log(fftLength, 2.0);
            this.fftLength = fftLength;
            fftBuffer = new Complex[fftLength];
            fftArgs = new FftEventArgs(fftBuffer);
        }

        private bool IsPowerOfTwo(int x)
        {
            return (x & (x - 1)) == 0;
        }

        public void Add(float value)
        {
            if (PerformFFT && FftCalculated != null)
            {
                fftBuffer[fftPos].X = (float)(value * FastFourierTransform.HammingWindow(fftPos, fftLength));
                fftBuffer[fftPos].Y = 0; // This is always zero with audio.
                fftPos++;
                if (fftPos >= fftLength)
                {
                    fftPos = 0;
                    FastFourierTransform.FFT(true, m, fftBuffer);
                    FftCalculated(this, fftArgs);
                }
            }
        }
    }

    public class FftEventArgs : EventArgs
    {
        public FftEventArgs(Complex[] result)
        {
            Result = result;
        }
        public Complex[] Result { get; private set; }
    }
}