// derived from org.gagravarr.opus.OpusFile

/*

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

lib 1400511 // VorbisJava (to unpack ogg file)

lib 1400502 // Concentus 1.0 (to decode OPUS audio in ogg file)

import org.gagravarr.ogg.*;

import org.gagravarr.ogg.audio.*;

import org.gagravarr.opus.*;

import static org.gagravarr.ogg.OggStreamIdentifier.OggStreamType;

import org.concentus.*;

sclass OpusFromStream_v2 implements OggAudioStream, OggAudioHeaders, Closeable {

  InputStream in;

  OggStreamPacketReader_v2 r;

  int sid = -1;

  int channels;

  OpusDecoder decoder;

  OpusInfo info;

  OpusTags tags;

  // channels = 1 or 2 (mono/stereo)

  *(InputStream *in, int *channels) throws IOException, OpusException {

    decoder = new OpusDecoder(48000, channels);

    r = new OggStreamPacketReader_v2(in);

  }

  bool initialized() { ret tags != null; }

  bool initStep() throws IOException {

    OggStreamPacket p = null;

    // find first packet (info)

    if (sid < 0) {

      while ((p = getNextPacket()) != null) {

        if (p.isBeginningOfStream() && p.getData().length > 10) {

          if (OpusPacketFactory.isOpusStream(p)) {

            sid = p.getSid();

            info = (OpusInfo) OpusPacketFactory.create(p);

            ifdef OpusFromStream_debug

              printVars OpusFromStream(+sid, +info);

            endifdef

            break;

          }

        }

      }

    }

    // find second packet (tags)

    if (tags == null) {  

      if ((p = getNextPacketWithSid(sid)) != null) {

        tags = (OpusTags) OpusPacketFactory.create(p);

        ifdef OpusFromStream_debug

          printVars OpusFromStream(+tags);

        endifdef

      }

    }

    ret initialized();

  }

  public OpusAudioData getNextAudioPacket() throws IOException {

    if (!initStep()) null;

    OggStreamPacket p = null;

    OpusPacket op = null;

    while ((p = getNextPacketWithSid(sid)) != null) {

      op = OpusPacketFactory.create(p);

      if (op cast OpusAudioData) ret op;

      else

        warn("Skipping non audio packet " + op + " mid audio stream");

    }

    null;

  }

  /**

   * Returns the Ogg Stream ID

   */

  public int getSid() {

    ret sid;

  }

  /**

   * This is an Opus file

   */

  public OggStreamType getType() {

    ret OggStreamIdentifier.OPUS_AUDIO;

  }

  public OpusInfo getInfo() {

    return info;

  }

  public OpusTags getTags() {

    return tags;

  }

  public void skipToGranule(long granulePosition) throws IOException {

    unimplemented();

  }

  /**

   * Opus doesn't have setup headers, so this is always null

   */

  public OggAudioSetupHeader getSetup() {

    null;

  }

  close {

    dispose r;

    dispose in;

  }

  // return some audio samples. null if none available

  short[] nextSamples() throws OpusException, IOException {

    OpusAudioData data;

    while ((data = getNextAudioPacket()) != null) {

      byte[] bytes = data.getData();

      if (empty(bytes)) continue;

      // decode packet

      short[] pcm = new[5760*channels]; // max opus frame size

      int nSamples = decoder.decode(bytes, 0, l(bytes), pcm, 0, l(pcm), false);

      ret subShortArray(pcm, 0, nSamples);

    }

    null;

  }

  public OggStreamPacket getNextPacket() throws IOException {

    in.mark(65536);

    OggStreamPacket p;

    try {

      p = r.getNextPacket();

    } catch (EOFException e) {

      ifdef OpusFromStream_debug

        print("OpusFromStream: EOFException, resetting");

      endifdef

      in.reset();

      null;

    }

    if (p == null) {

      ifdef OpusFromStream_debug

        print("OpusFromStream: packet null, resetting");

      endifdef

      in.reset();

    }

    ifdef OpusFromStream_debug

      printVars OpusFromStream(packet := p, +in);

    endifdef

    ret p;

  }

  /**

     * Returns the next packet with the given SID (Stream ID), or

     *  null if no more packets remain.

     * Any packets from other streams will be silently discarded.

     */

  public OggStreamPacket getNextPacketWithSid(int sid) throws IOException {

    OggStreamPacket p = null;

    while ((p = getNextPacket()) != null) {

      if (p.getSid() == sid) ret p;

    }

    null;

  }

  // e.g. for mark/reset

  static int bufferSizeNeeded() { ret 65536; }

}