/*

 * Copyright (c) 2007, 2016, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package com.sun.media.sound;

import java.io.EOFException;

import java.io.IOException;

import java.io.InputStream;

import javax.sound.midi.InvalidMidiDataException;

import javax.sound.midi.MetaMessage;

import javax.sound.midi.MidiEvent;

import javax.sound.midi.MidiMessage;

import javax.sound.midi.MidiSystem;

import javax.sound.midi.MidiUnavailableException;

import javax.sound.midi.Receiver;

import javax.sound.midi.Sequence;

import javax.sound.midi.Track;

import javax.sound.sampled.AudioFileFormat.Type;

import javax.sound.sampled.AudioFormat;

import javax.sound.sampled.AudioInputStream;

import javax.sound.sampled.UnsupportedAudioFileException;

/**

 * MIDI File Audio Renderer/Reader.

 *

 * @author Karl Helgason

 */

public final class SoftMidiAudioFileReader extends SunFileReader {

    private static final Type MIDI = new Type("MIDI", "mid");

    private static final AudioFormat format = new AudioFormat(44100, 16, 2,

                                                              true, false);

    private static StandardFileFormat getAudioFileFormat(final Sequence seq) {

        long totallen = seq.getMicrosecondLength() / 1000000;

        long len = (long) (format.getFrameRate() * (totallen + 4));

        return new StandardFileFormat(MIDI, format, len);

    }

    private AudioInputStream getAudioInputStream(final Sequence seq)

            throws InvalidMidiDataException {

        AudioInputStream stream;

        Receiver recv;

        try {

            stream = synth.openStream(format, null);

            recv = synth.getReceiver();

        } catch (MidiUnavailableException e) {

            throw new InvalidMidiDataException(e.toString());

        }

        float divtype = seq.getDivisionType();

        Track[] tracks = seq.getTracks();

        int[] trackspos = new int[tracks.length];

        int mpq = 500000;

        int seqres = seq.getResolution();

        long lasttick = 0;

        long curtime = 0;

        while (true) {

            MidiEvent selevent = null;

            int seltrack = -1;

            for (int i = 0; i < tracks.length; i++) {

                int trackpos = trackspos[i];

                Track track = tracks[i];

                if (trackpos < track.size()) {

                    MidiEvent event = track.get(trackpos);

                    if (selevent == null || event.getTick() < selevent.getTick()) {

                        selevent = event;

                        seltrack = i;

                    }

                }

            }

            if (seltrack == -1)

                break;

            trackspos[seltrack]++;

            long tick = selevent.getTick();

            if (divtype == Sequence.PPQ)

                curtime += ((tick - lasttick) * mpq) / seqres;

            else

                curtime = (long) ((tick * 1000000.0 * divtype) / seqres);

            lasttick = tick;

            MidiMessage msg = selevent.getMessage();

            if (msg instanceof MetaMessage) {

                if (divtype == Sequence.PPQ) {

                    if (((MetaMessage) msg).getType() == 0x51) {

                        byte[] data = ((MetaMessage) msg).getData();

                        if (data.length < 3) {

                            throw new InvalidMidiDataException();

                        }

                        mpq = ((data[0] & 0xff) << 16)

                                | ((data[1] & 0xff) << 8) | (data[2] & 0xff);

                    }

                }

            } else {

                recv.send(msg, curtime);

            }

        }

        long totallen = curtime / 1000000;

        long len = (long) (stream.getFormat().getFrameRate() * (totallen + 4));

        stream = new AudioInputStream(stream, stream.getFormat(), len);

        return stream;

    }

    @Override

    public AudioInputStream getAudioInputStream(final InputStream stream)

            throws UnsupportedAudioFileException, IOException {

        stream.mark(200);

        try {

            return getAudioInputStream(MidiSystem.getSequence(stream));

        } catch (InvalidMidiDataException | EOFException ignored) {

            // stream is unsupported or the header is less than was expected

            stream.reset();

            throw new UnsupportedAudioFileException();

        }

    }

    @Override

    StandardFileFormat getAudioFileFormatImpl(final InputStream stream)

            throws UnsupportedAudioFileException, IOException {

        try {

            return getAudioFileFormat(MidiSystem.getSequence(stream));

        } catch (final InvalidMidiDataException ignored) {

            throw new UnsupportedAudioFileException();

        }

    }

}