// fft_frame.java     fft_frame  ok.wav junk.wav
//                    uses  read_wave.java
//                    uses  Cxfft.java

import java.*;
import java.awt.*;
import java.awt.event.*;

public class fft_frame extends Frame
{
  int width = 512;
  int height = 512;
  int S[] = new int[width];
  int fctr; // for scaling plot

  public fft_frame(String file_in, String file_out)
  {
    double amin, amax, aavg, y;
    double bmin, bmax, bavg;
    double smin, smax, savg;
    int m; // next power of 2
    int mscale, mcnt;
    int j;  // combine frequencies to fit into S

    for(int i=0; i<width; i++)
    {
      S[i] = height/2;
    }
    setTitle("fft_frame");
    setSize(width,height);
    setBackground(Color.white);
    setForeground(Color.black);
    addWindowListener(new WindowAdapter()
    {
      public void windowClosing(WindowEvent e)
      {
        System.exit(0);
      }
    });
    setVisible(true);

    read_wav R = new read_wav(file_in, file_out, false);
    // wav_read(file_in);  done by constructor
    int n = R.outix;  // number of sound samples
    for(m=64; m<2500000; m*=2) if(m>2*n) break;
    System.out.println("power of 2 m="+m);

    System.out.println("have "+n+" points for FFT");
    double A[] = new double[m];
    double B[] = new double[m];
    double B2[] = new double[m];
    for(int i=0; i<2*n; i+=2) A[i] = (double)R.A[i/2]; // real
    for(int i=1; i<2*n; i+=2) A[i] = 0.0;              // imag
    for(int i=2*n; i<m; i++) A[i] = 0.0; // zero to power of 2

    // optional, compute statistics
    amin = A[0];
    amax = A[0];
    aavg = 0.0;
    for(int i=0; i<2*n; i+=2)
    {
      amin = Math.min(amin, A[i]);
      amax = Math.max(amax, A[i]);
      aavg += A[i];
    }
    aavg = aavg/(double)n;
    System.out.println("input min="+amin+", max="+amax+", avg="+aavg);

    B = Cxfft.fft(A,1.0);

    // compute statistics for scaling plot
    bmax = Math.sqrt(B[2]*B[2]+B[3]*B[3]);
    bmin = Math.sqrt(B[2]*B[2]+B[3]*B[3]);
    bavg = 0.0;
    for(int i=2; i<2*n; i+=2) // skip DC frequency bin
    {
      y = Math.sqrt(B[i]*B[i]+B[i+1]*B[i+1]);
      bmin = Math.min(bmin, y);
      bmax = Math.max(bmax, y);
      bavg += y;
    }
    bavg = bavg/(double)n;
    System.out.println("transform bmin="+bmin+", bmax="+bmax+", bavg="+bavg);

    // scale for plotting magnitude of transform
    mscale = n/width; // number of points to combine
    System.out.println("mscale="+mscale+", should be n="+n+"/width="+width);

    S[0] = 0; // DC
    mcnt = 0;
    j = 0;
    for(int i=2; i<2*n; i+=2)
    {
      if(mcnt>=mscale)
      {
	mcnt = 0;
        // S[j] = (int)((double)S[j]/(double)mscale);
        j++;
        if(j>=width) break;
        S[j] = 0;
      }
      y = Math.sqrt(B[i]*B[i]+B[i+1]*B[i+1]);
      y = height*(int)((y-bmin)/(bavg));
      S[j] = S[j]+ (int)y;
      mcnt++;
    }
    repaint();

    // optional, compute statistics
    smin = S[0];
    smax = S[0];
    savg = 0.0;
    for(int i=1; i<width; i++)
    {
      smin = Math.min(smin, S[i]);
      smax = Math.max(smax, S[i]);
      savg += S[i];
    }
    savg = savg/(double)width;
    System.out.println("plot smin="+smin+", smax="+smax+", savg="+savg);

    int sfctr = 0;
    for(int i=0; i<24; i++)
    {
       System.out.println("S["+i+"]="+S[i]);
       sfctr = sfctr+S[i];
    }
    fctr = (sfctr/24)/height;
    System.out.println("plot fctr="+fctr); // fudged

    // change frequency bins goes here


    A = Cxfft.fft(B,-1.0); // inverse transform, back to time domain

    // compute statistics, may be needed for scaling
    amin = A[0];
    amax = A[0];
    aavg = 0.0;
    for(int i=0; i<2*n; i+=2)
    {
      amin = Math.min(amin, A[i]);
      amax = Math.max(amax, A[i]);
      aavg += A[i];
    }
    aavg = aavg/(double)n;
    System.out.println("output min="+amin+", max="+amax+", avg="+aavg);

    // scale for  .wav  output
    for(int i=0; i<2*n; i+=2) R.A[i/2] = (int)(0.99*A[i]); // fudge
    for(int i=0; i<n; i++)
    {
      if(R.A[i]>127)  R.A[i]= 127;
      if(R.A[i]<-127) R.A[i]=-127;
    }
    R.wav_write(file_out);
    repaint();
  }

  public void paint(Graphics g)
  {
    int sprev = S[0]/fctr;
    g.setColor(Color.black);
    for(int i=1; i<width; i++) // width-1 lines
    {
      g.drawLine(i-1, height-sprev, i, height-S[i]/fctr);
      sprev = S[i]/fctr;
    }
  } // end paint

  public static void main (String[] args)
  {
    String file_in = "ok.wav";
    if(args.length>0)
    {
      file_in = args[0];
    }
    String file_out = "junk.wav";
    if(args.length>1)
    {
      file_out = args[1];
    }
    new fft_frame(file_in, file_out);
  } // end main
} // end class fft_frame of fft_frame.java