package org.herac.tuxguitar.io.gervill;

import java.io.OutputStream;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

import javax.sound.midi.MetaMessage;
import javax.sound.midi.MidiEvent;
import javax.sound.midi.MidiMessage;
import javax.sound.midi.Receiver;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;

import org.herac.tuxguitar.song.models.TGDuration;

public class MidiToAudioWriter {

  private static void sort(List<MidiEvent> events) {
    Collections.sort(events, new Comparator<MidiEvent>() {
      public int compare(MidiEvent e1, MidiEvent e2) {
        return (int) (e1.getTick() - e2.getTick());
      }
    });
  }

  public static void write(OutputStream out, List<MidiEvent> events,
      MidiToAudioSettings settings) throws Throwable {
    MidiToAudioSynth.instance().openSynth();

    int usqTempo = 60000000 / 120;
    long previousTick = 0;
    long timePosition = 0;
    MidiToAudioWriter.sort(events);
    Receiver receiver = MidiToAudioSynth.instance().getReceiver();
    AudioInputStream stream = MidiToAudioSynth.instance().getStream();

    for (final MidiEvent event : events) {
      MidiMessage msg = event.getMessage();

      timePosition += ((event.getTick() - previousTick) * usqTempo)
          / TGDuration.QUARTER_TIME;

      if (msg instanceof MetaMessage) {
        if (((MetaMessage) msg).getType() == 0x51) {
          byte[] data = ((MetaMessage) msg).getData();
          usqTempo = ((data[0] & 0xff) << 16) | ((data[1] & 0xff) << 8)
              | (data[2] & 0xff);
        }
      } else {
        receiver.send(msg, timePosition);
      }
      previousTick = event.getTick();
    }

    long duration = (long) (stream.getFormat().getFrameRate() * ((timePosition / 1000000.0)));

    AudioInputStream srcStream = new AudioInputStream(stream, stream
        .getFormat(), duration);
    AudioInputStream dstStream = AudioSystem.getAudioInputStream(settings
        .getFormat(), srcStream);
    AudioSystem.write(new AudioInputStream(dstStream, dstStream.getFormat(),
        duration), settings.getType(), out);

    dstStream.close();
    srcStream.close();

    MidiToAudioSynth.instance().closeSynth();
  }
}