package org.jcodec.audio;

import java.nio.FloatBuffer;
import org.jcodec.common.AudioFormat;
import org.jcodec.common.Preconditions;

public class ChannelMerge implements AudioFilter {
  private AudioFormat format;
  
  public ChannelMerge(AudioFormat format) {
    this.format = format;
  }
  
  public void filter(FloatBuffer[] _in, long[] inPos, FloatBuffer[] out) {
    if (_in.length != this.format.getChannels())
      throw new IllegalArgumentException("Channel merge must be supplied with " + this.format.getChannels() + " input buffers to hold the channels."); 
    if (out.length != 1)
      throw new IllegalArgumentException("Channel merget invoked on more then one output"); 
    FloatBuffer out0 = out[0];
    int min = Integer.MAX_VALUE;
    for (int k = 0; k < _in.length; k++) {
      if (_in[k].remaining() < min)
        min = _in[k].remaining(); 
    } 
    for (int j = 0; j < _in.length; j++)
      Preconditions.checkState((_in[j].remaining() == min)); 
    if (out0.remaining() < min * _in.length)
      throw new IllegalArgumentException("Supplied output buffer is not big enough to hold " + min + " * " + _in.length + " = " + min * _in.length + " output samples."); 
    for (int i = 0; i < min; i++) {
      for (int m = 0; m < _in.length; m++)
        out0.put(_in[m].get()); 
    } 
  }
  
  public int getDelay() {
    return 0;
  }
  
  public int getNInputs() {
    return this.format.getChannels();
  }
  
  public int getNOutputs() {
    return 1;
  }
}