/**
 * Copyright 2013 JogAmp Community. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of
 *       conditions and the following disclaimer.
 *
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list
 *       of conditions and the following disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are those of the
 * authors and should not be interpreted as representing official policies, either expressed
 * or implied, of JogAmp Community.
 */
package jogamp.opengl.openal.av;


import java.nio.ByteBuffer;
import java.util.Arrays;

import com.jogamp.common.util.LFRingbuffer;
import com.jogamp.common.util.Ringbuffer;
import com.jogamp.common.util.locks.LockFactory;
import com.jogamp.common.util.locks.RecursiveLock;
import com.jogamp.openal.AL;
import com.jogamp.openal.ALC;
import com.jogamp.openal.ALCcontext;
import com.jogamp.openal.ALCdevice;
import com.jogamp.openal.ALExt;
import com.jogamp.openal.ALFactory;
import com.jogamp.openal.util.ALHelpers;
import com.jogamp.opengl.util.av.AudioSink;

/***
 * OpenAL Audio Sink
 */
public class ALAudioSink implements AudioSink {

    private static final String AL_SOFT_buffer_samples = "AL_SOFT_buffer_samples";
    private static final ALC alc;
    private static final AL al;
    private static final ALExt alExt;
    private static final boolean staticAvailable;

    private String deviceSpecifier;
    private ALCdevice device;
    private boolean hasSOFTBufferSamples;
    private AudioFormat preferredAudioFormat;
    private ALCcontext context;
    private final RecursiveLock lock = LockFactory.createRecursiveLock();

    /** Playback speed, range [0.5 - 2.0], default 1.0. */
    private float playSpeed;
    private float volume = 1.0f;

    static class ALAudioFrame extends AudioFrame {
        private final int alBuffer;

        ALAudioFrame(int alBuffer) {
            this.alBuffer = alBuffer;
        }
        public ALAudioFrame(int alBuffer, int pts, int duration, int dataSize) {
            super(pts, duration, dataSize);
            this.alBuffer = alBuffer;
        }

        /** Get this frame's OpenAL buffer name */
        public final int getALBuffer() { return alBuffer; }

        public String toString() {
            return "ALAudioFrame[pts " + pts + " ms, l " + duration + " ms, " + byteSize + " bytes, buffer "+alBuffer+"]";
        }
    }

    // private ALAudioFrame[] alFrames = null;
    private int[] alBufferNames = null;
    private int frameGrowAmount = 0;
    private int frameLimit = 0;

    private Ringbuffer<ALAudioFrame> alFramesAvail = null;
    private Ringbuffer<ALAudioFrame> alFramesPlaying = null;
    private volatile int alBufferBytesQueued = 0;
    private volatile int playingPTS = AudioFrame.INVALID_PTS;
    private volatile int enqueuedFrameCount;

    private int[] alSource = null;
    private AudioFormat chosenFormat;
    private int alChannelLayout;
    private int alSampleType;
    private int alFormat;
    private boolean initialized;

    private volatile boolean playRequested = false;

    static {
        ALC _alc = null;
        AL _al = null;
        ALExt _alExt = null;
        try {
            _alc = ALFactory.getALC();
            _al = ALFactory.getAL();
            _alExt = ALFactory.getALExt();
        } catch(Throwable t) {
            if( DEBUG ) {
                System.err.println("ALAudioSink: Catched "+t.getClass().getName()+": "+t.getMessage());
                t.printStackTrace();
            }
        }
        alc = _alc;
        al = _al;
        alExt = _alExt;
        staticAvailable = null != alc && null != al && null != alExt;
    }

    public ALAudioSink() {
        initialized = false;
        chosenFormat = null;

        if( !staticAvailable ) {
            return;
        }

        try {
            // Get handle to default device.
            device = alc.alcOpenDevice(null);
            if (device == null) {
                throw new RuntimeException("ALAudioSink: Error opening default OpenAL device");
            }

            // Get the device specifier.
            deviceSpecifier = alc.alcGetString(device, ALC.ALC_DEVICE_SPECIFIER);
            if (deviceSpecifier == null) {
                throw new RuntimeException("ALAudioSink: Error getting specifier for default OpenAL device");
            }

            // Create audio context.
            context = alc.alcCreateContext(device, null);
            if (context == null) {
                throw new RuntimeException("ALAudioSink: Error creating OpenAL context for "+deviceSpecifier);
            }

            lockContext();
            try {
                // Check for an error.
                if ( alc.alcGetError(device) != ALC.ALC_NO_ERROR ) {
                    throw new RuntimeException("ALAudioSink: Error making OpenAL context current");
                }

                hasSOFTBufferSamples = al.alIsExtensionPresent(AL_SOFT_buffer_samples);
                preferredAudioFormat = queryPreferredAudioFormat();
                if( DEBUG ) {
                    System.out.println("ALAudioSink: OpenAL Extensions:"+al.alGetString(AL.AL_EXTENSIONS));
                    System.out.println("ALAudioSink: Null device OpenAL Extensions:"+alc.alcGetString(null, ALC.ALC_EXTENSIONS));
                    System.out.println("ALAudioSink: Device "+deviceSpecifier+" OpenAL Extensions:"+alc.alcGetString(device, ALC.ALC_EXTENSIONS));
                    System.out.println("ALAudioSink: hasSOFTBufferSamples "+hasSOFTBufferSamples);
                    System.out.println("ALAudioSink: preferredAudioFormat "+preferredAudioFormat);
                }

                // Create source
                {
                    alSource = new int[1];
                    al.alGenSources(1, alSource, 0);
                    final int err = al.alGetError();
                    if( err != AL.AL_NO_ERROR ) {
                        alSource = null;
                        throw new RuntimeException("ALAudioSink: Error generating Source: 0x"+Integer.toHexString(err));
                    }
                }

                if( DEBUG ) {
                    System.err.println("ALAudioSink: Using device: " + deviceSpecifier);
                }
                initialized = true;
            } finally {
                unlockContext();
            }
            return;
        } catch ( Exception e ) {
            if( DEBUG ) {
                System.err.println(e.getMessage());
            }
            destroy();
        }
    }

    private final AudioFormat queryPreferredAudioFormat() {
        int sampleRate = DefaultFormat.sampleRate;
        final int[] value = new int[1];
        alc.alcGetIntegerv(device, ALC.ALC_FREQUENCY, 1, value, 0);
        if ( alc.alcGetError(device) == ALC.ALC_NO_ERROR ) {
            sampleRate = value[0];
        }
        return new AudioFormat(sampleRate, DefaultFormat.sampleSize, DefaultFormat.channelCount, DefaultFormat.signed, DefaultFormat.fixedP, DefaultFormat.planar, DefaultFormat.littleEndian);
    }

    private final void lockContext() {
        lock.lock();
        alc.alcMakeContextCurrent(context);
    }
    private final void unlockContext() {
        alc.alcMakeContextCurrent(null);
        lock.unlock();
    }
    private final void destroyContext() {
        lock.lock();
        try {
            if( null != context ) {
                try {
                    alc.alcDestroyContext(context);
                } catch (Throwable t) {
                    if( DEBUG ) {
                        System.err.println("Catched "+t.getClass().getName()+": "+t.getMessage());
                        t.printStackTrace();
                    }
                }
                context = null;
            }
            // unroll lock !
            while(lock.getHoldCount() > 1) {
                lock.unlock();
            }
        } finally {
            lock.unlock();
        }
    }

    @Override
    public final String toString() {
        final int alSrcName = null != alSource ? alSource[0] : 0;
        final int alBuffersLen = null != alBufferNames ? alBufferNames.length : 0;
        final int ctxHash = context != null ? context.hashCode() : 0;
        return "ALAudioSink[init "+initialized+", playRequested "+playRequested+", device "+deviceSpecifier+", ctx "+toHexString(ctxHash)+", alSource "+alSrcName+
               ", chosen "+chosenFormat+
               ", al[chan "+ALHelpers.alChannelLayoutName(alChannelLayout)+", type "+ALHelpers.alSampleTypeName(alSampleType)+
               ", fmt "+toHexString(alFormat)+", soft "+hasSOFTBufferSamples+
               "], playSpeed "+playSpeed+", buffers[total "+alBuffersLen+", avail "+alFramesAvail.size()+", "+
               "queued["+alFramesPlaying.size()+", apts "+getPTS()+", "+getQueuedTime() + " ms, " + alBufferBytesQueued+" bytes], "+
               "queue[g "+frameGrowAmount+", l "+frameLimit+"]";
    }

    public final String getPerfString() {
        final int alBuffersLen = null != alBufferNames ? alBufferNames.length : 0;
        return "Play [buffer "+alFramesPlaying.size()+"/"+alBuffersLen+", apts "+getPTS()+", "+getQueuedTime() + " ms, " + alBufferBytesQueued+" bytes]";
    }

    @Override
    public final AudioFormat getPreferredFormat() {
        if( !staticAvailable ) {
            return null;
        }
        return preferredAudioFormat;
    }

    @Override
    public final int getMaxSupportedChannels() {
        if( !staticAvailable ) {
            return 0;
        }
        return hasSOFTBufferSamples ? 8 : 2;
    }

    @Override
    public final boolean isSupported(AudioFormat format) {
        if( !staticAvailable ) {
            return false;
        }
        if( format.planar || !format.littleEndian ) {
            // FIXME big-endian supported w/ SOFT where it's native format!
            return false;
        }
        final int alChannelLayout = ALHelpers.getDefaultALChannelLayout(format.channelCount);
        if( AL.AL_NONE != alChannelLayout ) {
            final int alSampleType = ALHelpers.getALSampleType(format.sampleSize, format.signed, format.fixedP);
            if( AL.AL_NONE != alSampleType ) {
                lockContext();
                try {
                    final int alFormat = ALHelpers.getALFormat(alChannelLayout, alSampleType, hasSOFTBufferSamples, al, alExt);
                    return AL.AL_NONE != alFormat;
                } finally {
                    unlockContext();
                }
            }
        }
        return false;
    }

    @Override
    public final boolean init(AudioFormat requestedFormat, float frameDuration, int initialQueueSize, int queueGrowAmount, int queueLimit) {
        if( !staticAvailable ) {
            return false;
        }
        alChannelLayout = ALHelpers.getDefaultALChannelLayout(requestedFormat.channelCount);
        alSampleType = ALHelpers.getALSampleType(requestedFormat.sampleSize, requestedFormat.signed, requestedFormat.fixedP);
        lockContext();
        try {
            if( AL.AL_NONE != alChannelLayout && AL.AL_NONE != alSampleType ) {
                alFormat = ALHelpers.getALFormat(alChannelLayout, alSampleType, hasSOFTBufferSamples, al, alExt);
            } else {
                alFormat = AL.AL_NONE;
            }
            if( AL.AL_NONE == alFormat ) {
                // not supported
                return false;
            }
            // Allocate buffers
            destroyBuffers();
            {
                final float useFrameDuration = frameDuration > 1f ? frameDuration : AudioSink.DefaultFrameDuration;
                final int initialFrameCount = requestedFormat.getFrameCount(
                        initialQueueSize > 0 ? initialQueueSize : AudioSink.DefaultInitialQueueSize, useFrameDuration);
                // frameDuration, int initialQueueSize, int queueGrowAmount, int queueLimit) {
                alBufferNames = new int[initialFrameCount];
                al.alGenBuffers(initialFrameCount, alBufferNames, 0);
                final int err = al.alGetError();
                if( err != AL.AL_NO_ERROR ) {
                    alBufferNames = null;
                    throw new RuntimeException("ALAudioSink: Error generating Buffers: 0x"+Integer.toHexString(err));
                }
                final ALAudioFrame[] alFrames = new ALAudioFrame[initialFrameCount];
                for(int i=0; i<initialFrameCount; i++) {
                    alFrames[i] = new ALAudioFrame(alBufferNames[i]);
                }

                alFramesAvail = new LFRingbuffer<ALAudioFrame>(alFrames);
                alFramesPlaying = new LFRingbuffer<ALAudioFrame>(ALAudioFrame[].class, initialFrameCount);
                this.frameGrowAmount = requestedFormat.getFrameCount(
                        queueGrowAmount > 0 ? queueGrowAmount : AudioSink.DefaultQueueGrowAmount, useFrameDuration);
                this.frameLimit = requestedFormat.getFrameCount(
                        queueLimit > 0 ? queueLimit : AudioSink.DefaultQueueLimitWithVideo, useFrameDuration);
            }
        } finally {
            unlockContext();
        }

        chosenFormat = requestedFormat;
        return true;
    }

    private static int[] concat(int[] first, int[] second) {
        final int[] result = Arrays.copyOf(first, first.length + second.length);
        System.arraycopy(second, 0, result, first.length, second.length);
        return result;
    }
    /**
    private static <T> T[] concat(T[] first, T[] second) {
        final T[] result = Arrays.copyOf(first, first.length + second.length);
        System.arraycopy(second, 0, result, first.length, second.length);
        return result;
    } */

    private boolean growBuffers() {
        if( !alFramesAvail.isEmpty() || !alFramesPlaying.isFull() ) {
            throw new InternalError("Buffers: Avail is !empty "+alFramesAvail+" or Playing is !full "+alFramesPlaying);
        }
        if( alFramesAvail.capacity() >= frameLimit || alFramesPlaying.capacity() >= frameLimit ) {
            if( DEBUG ) {
                System.err.println(getThreadName()+": ALAudioSink.growBuffers: Frame limit "+frameLimit+" reached: Avail "+alFramesAvail+", Playing "+alFramesPlaying);
            }
            return false;
        }

        final int[] newALBufferNames = new int[frameGrowAmount];
        al.alGenBuffers(frameGrowAmount, newALBufferNames, 0);
        final int err = al.alGetError();
        if( err != AL.AL_NO_ERROR ) {
            if( DEBUG ) {
                System.err.println(getThreadName()+": ALAudioSink.growBuffers: Error generating "+frameGrowAmount+" new Buffers: 0x"+Integer.toHexString(err));
            }
            return false;
        }
        alBufferNames = concat(alBufferNames, newALBufferNames);

        final ALAudioFrame[] newALBuffers = new ALAudioFrame[frameGrowAmount];
        for(int i=0; i<frameGrowAmount; i++) {
            newALBuffers[i] = new ALAudioFrame(newALBufferNames[i]);
        }
        // alFrames = concat(alFrames , newALBuffers);

        alFramesAvail.growEmptyBuffer(newALBuffers);
        alFramesPlaying.growFullBuffer(frameGrowAmount);
        if( alFramesAvail.isEmpty() || alFramesPlaying.isFull() ) {
            throw new InternalError("Buffers: Avail is empty "+alFramesAvail+" or Playing is full "+alFramesPlaying);
        }
        if( DEBUG ) {
            System.err.println(getThreadName()+": ALAudioSink: Buffer grown "+frameGrowAmount+": Avail "+alFramesAvail+", playing "+alFramesPlaying);
        }
        return true;
    }

    private void destroyBuffers() {
        if( !staticAvailable ) {
            return;
        }
        if( null != alBufferNames ) {
            try {
                al.alDeleteBuffers(alBufferNames.length, alBufferNames, 0);
            } catch (Throwable t) {
                if( DEBUG ) {
                    System.err.println("Catched "+t.getClass().getName()+": "+t.getMessage());
                    t.printStackTrace();
                }
            }
            alFramesAvail.clear();
            alFramesAvail = null;
            alFramesPlaying.clear();
            alFramesPlaying = null;
            alBufferBytesQueued = 0;
            // alFrames = null;
            alBufferNames = null;
        }
    }

    @Override
    public final void destroy() {
        initialized = false;
        if( !staticAvailable ) {
            return;
        }
        if( null != context ) {
            lockContext();
        }
        try {
            stopImpl();
            if( null != alSource ) {
                try {
                    al.alDeleteSources(1, alSource, 0);
                } catch (Throwable t) {
                    if( DEBUG ) {
                        System.err.println("Catched "+t.getClass().getName()+": "+t.getMessage());
                        t.printStackTrace();
                    }
                }
                alSource = null;
            }

            destroyBuffers();
        } finally {
            destroyContext();
        }
        if( null != device ) {
            try {
                alc.alcCloseDevice(device);
            } catch (Throwable t) {
                if( DEBUG ) {
                    System.err.println("Catched "+t.getClass().getName()+": "+t.getMessage());
                    t.printStackTrace();
                }
            }
            device = null;
        }
        chosenFormat = null;
    }

    @Override
    public final boolean isInitialized() {
        return initialized;
    }

    private final int dequeueBuffer(boolean wait) {
        int alErr = AL.AL_NO_ERROR;
        final int releaseBufferCount;
        if( alBufferBytesQueued > 0 ) {
            final int releaseBufferLimes = Math.max(1, alFramesPlaying.size() / 4 );
            final int[] val=new int[1];
            int i=0;
            do {
                al.alGetSourcei(alSource[0], AL.AL_BUFFERS_PROCESSED, val, 0);
                alErr = al.alGetError();
                if( AL.AL_NO_ERROR != alErr ) {
                    throw new RuntimeException("ALError "+toHexString(alErr)+" while quering processed buffers at source. "+this);
                }
                if( wait && val[0] < releaseBufferLimes ) {
                    i++;
                    // clip wait at [2 .. 100] ms
                    final int avgBufferDura = chosenFormat.getBytesDuration( alBufferBytesQueued / alFramesPlaying.size() );
                    final int sleep = Math.max(2, Math.min(100, releaseBufferLimes * avgBufferDura));
                    if( DEBUG ) {
                        System.err.println(getThreadName()+": ALAudioSink: Dequeue.wait["+i+"]: avgBufferDura "+avgBufferDura+", releaseBufferLimes "+releaseBufferLimes+", sleep "+sleep+" ms, playImpl "+(AL.AL_PLAYING == getSourceState())+", processed "+val[0]+", "+this);
                    }
                    unlockContext();
                    try {
                        Thread.sleep( sleep - 1 );
                    } catch (InterruptedException e) {
                    } finally {
                        lockContext();
                    }
                }
            } while ( wait && val[0] < releaseBufferLimes && alBufferBytesQueued > 0 );
            releaseBufferCount = val[0];
        } else {
            releaseBufferCount = 0;
        }

        if( releaseBufferCount > 0 ) {
            int[] buffers=new int[releaseBufferCount];
            al.alSourceUnqueueBuffers(alSource[0], releaseBufferCount, buffers, 0);
            alErr = al.alGetError();
            if( AL.AL_NO_ERROR != alErr ) {
                throw new RuntimeException("ALError "+toHexString(alErr)+" while dequeueing "+releaseBufferCount+" buffers. "+this);
            }
            for ( int i=0; i<releaseBufferCount; i++ ) {
                final ALAudioFrame releasedBuffer = alFramesPlaying.get();
                if( null == releasedBuffer ) {
                    throw new InternalError("Internal Error: "+this);
                }
                if( releasedBuffer.alBuffer != buffers[i] ) {
                    alFramesAvail.dump(System.err, "Avail-deq02-post");
                    alFramesPlaying.dump(System.err, "Playi-deq02-post");
                    throw new InternalError("Buffer name mismatch: dequeued: "+buffers[i]+", released "+releasedBuffer+", "+this);
                }
                alBufferBytesQueued -= releasedBuffer.getByteSize();
                if( !alFramesAvail.put(releasedBuffer) ) {
                    throw new InternalError("Internal Error: "+this);
                }
            }
        }
        return releaseBufferCount;
    }
    private final void dequeueForceAll() {
        while ( !alFramesPlaying.isEmpty() ) {
            final ALAudioFrame releasedBuffer = alFramesPlaying.get();
            if( null == releasedBuffer ) {
                throw new InternalError("Internal Error: "+this);
            }
            alBufferBytesQueued -= releasedBuffer.getByteSize();
            if( !alFramesAvail.put(releasedBuffer) ) {
                throw new InternalError("Internal Error: "+this);
            }
        }
        if( 0 != alBufferBytesQueued ) {
            throw new InternalError("Internal Error: "+this);
        }
    }

    private final int dequeueBuffer(boolean wait, int inPTS, int inDuration) {
        final int dequeuedBufferCount = dequeueBuffer( wait );
        final ALAudioFrame currentBuffer = alFramesPlaying.peek();
        if( null != currentBuffer ) {
            playingPTS = currentBuffer.getPTS();
        } else {
            playingPTS = inPTS;
        }
        if( DEBUG ) {
            if( dequeuedBufferCount > 0 ) {
                System.err.println(getThreadName()+": ALAudioSink: Write "+inPTS+", "+inDuration+" ms, dequeued "+dequeuedBufferCount+", wait "+wait+", "+getPerfString());
            }
        }
        return dequeuedBufferCount;
    }

    @Override
    public final AudioFrame enqueueData(AudioDataFrame audioDataFrame) {
        return enqueueData(audioDataFrame.getPTS(), audioDataFrame.getData(), audioDataFrame.getByteSize());
    }

    @Override
    public final AudioFrame enqueueData(int pts, ByteBuffer bytes, int byteCount) {
        if( !initialized || null == chosenFormat ) {
            return null;
        }
        final ALAudioFrame alFrame;
        int alErr = AL.AL_NO_ERROR;

        // OpenAL consumes buffers in the background
        // we first need to initialize the OpenAL buffers then
        // start continuous playback.
        lockContext();
        try {
            alErr = al.alGetError();
            if(al.alGetError() != AL.AL_NO_ERROR) {
                throw new RuntimeException("ALError "+toHexString(alErr)+" while makeCurrent. "+this);
            }

            final int duration = chosenFormat.getBytesDuration(byteCount);
            final boolean dequeueDone;
            if( alFramesAvail.isEmpty() ) {
                // try to dequeue first
                dequeueDone = dequeueBuffer(false, pts, duration) > 0;
                if( alFramesAvail.isEmpty() ) {
                    // try to grow
                    growBuffers();
                }
            } else {
                dequeueDone = false;
            }
            if( !dequeueDone && alFramesPlaying.size() > 0 ) { // dequeue only possible if playing ..
                final boolean wait = isPlayingImpl0() && alFramesAvail.isEmpty(); // possible if grow failed or already exceeds it's limit!
                dequeueBuffer(wait, pts, duration);
            }

            alFrame = alFramesAvail.get();
            if( null == alFrame ) {
                alFramesAvail.dump(System.err, "Avail");
                throw new InternalError("Internal Error: avail.get null "+alFramesAvail+", "+this);
            }
            alFrame.setPTS(pts);
            alFrame.setDuration(duration);
            alFrame.setByteSize(byteCount);
            if( !alFramesPlaying.put( alFrame ) ) {
                throw new InternalError("Internal Error: "+this);
            }
            if( hasSOFTBufferSamples ) {
                final int samplesPerChannel = chosenFormat.getBytesSampleCount(byteCount) / chosenFormat.channelCount;
                // final int samplesPerChannel = ALHelpers.bytesToSampleCount(byteCount, alChannelLayout, alSampleType);
                alExt.alBufferSamplesSOFT(alFrame.alBuffer, chosenFormat.sampleRate, alFormat,
                                          samplesPerChannel, alChannelLayout, alSampleType, bytes);
            } else {
                al.alBufferData(alFrame.alBuffer, alFormat, bytes, byteCount, chosenFormat.sampleRate);
            }

            final int[] alBufferNames = new int[] { alFrame.alBuffer };
            al.alSourceQueueBuffers(alSource[0], 1, alBufferNames, 0);
            alErr = al.alGetError();
            if(al.alGetError() != AL.AL_NO_ERROR) {
                throw new RuntimeException("ALError "+toHexString(alErr)+" while queueing buffer "+toHexString(alBufferNames[0])+". "+this);
            }
            alBufferBytesQueued += byteCount;
            enqueuedFrameCount++;

            playImpl(); // continue playing, fixes issue where we ran out of enqueued data!
        } finally {
            unlockContext();
        }
        return alFrame;
    }

    @Override
    public final boolean isPlaying() {
        if( !initialized || null == chosenFormat ) {
            return false;
        }
        if( playRequested ) {
            lockContext();
            try {
                return isPlayingImpl0();
            } finally {
                unlockContext();
            }
        } else {
            return false;
        }
    }
    private final boolean isPlayingImpl0() {
        if( playRequested ) {
            return AL.AL_PLAYING == getSourceState();
        } else {
            return false;
        }
    }
    private final int getSourceState() {
        final int[] val = new int[1];
        al.alGetSourcei(alSource[0], AL.AL_SOURCE_STATE, val, 0);
        final int alErr = al.alGetError();
        if(al.alGetError() != AL.AL_NO_ERROR) {
            throw new RuntimeException("ALError "+toHexString(alErr)+" while querying SOURCE_STATE. "+this);
        }
        return val[0];
    }

    @Override
    public final void play() {
        if( !initialized || null == chosenFormat ) {
            return;
        }
        playRequested = true;
        lockContext();
        try {
            playImpl();
            if( DEBUG ) {
                System.err.println(getThreadName()+": ALAudioSink: PLAY playImpl "+(AL.AL_PLAYING == getSourceState())+", "+this);
            }
        } finally {
            unlockContext();
        }
    }
    private final void playImpl() {
        if( playRequested && AL.AL_PLAYING != getSourceState() ) {
            al.alSourcePlay(alSource[0]);
            final int alErr = al.alGetError();
            if(al.alGetError() != AL.AL_NO_ERROR) {
                throw new RuntimeException("ALError "+toHexString(alErr)+" while start playing. "+this);
            }
        }
    }

    @Override
    public final void pause() {
        if( !initialized || null == chosenFormat ) {
            return;
        }
        if( playRequested ) {
            lockContext();
            try {
                pauseImpl();
                if( DEBUG ) {
                    System.err.println(getThreadName()+": ALAudioSink: PAUSE playImpl "+(AL.AL_PLAYING == getSourceState())+", "+this);
                }
            } finally {
                unlockContext();
            }
        }
    }
    private final void pauseImpl() {
        if( isPlayingImpl0() ) {
            playRequested = false;
            al.alSourcePause(alSource[0]);
            final int alErr = al.alGetError();
            if(al.alGetError() != AL.AL_NO_ERROR) {
                throw new RuntimeException("ALError "+toHexString(alErr)+" while pausing. "+this);
            }
        }
    }
    private final void stopImpl() {
        if( AL.AL_STOPPED != getSourceState() ) {
            playRequested = false;
            al.alSourceStop(alSource[0]);
            final int alErr = al.alGetError();
            if(al.alGetError() != AL.AL_NO_ERROR) {
                throw new RuntimeException("ALError "+toHexString(alErr)+" while pausing. "+this);
            }
        }
    }

    @Override
    public final float getPlaySpeed() { return playSpeed; }

    @Override
    public final boolean setPlaySpeed(float rate) {
        if( !initialized || null == chosenFormat ) {
            return false;
        }
        lockContext();
        try {
            if( Math.abs(1.0f - rate) < 0.01f ) {
                rate = 1.0f;
            }
            if( 0.5f <= rate && rate <= 2.0f ) { // OpenAL limits
                playSpeed = rate;
                al.alSourcef(alSource[0], AL.AL_PITCH, playSpeed);
                return true;
            }
        } finally {
            unlockContext();
        }
        return false;
    }

    @Override
    public final float getVolume() {
        return volume;
    }

    @Override
    public final boolean setVolume(float v) {
        if( !initialized || null == chosenFormat ) {
            return false;
        }
        lockContext();
        try {
            if( Math.abs(v) < 0.01f ) {
                v = 0.0f;
            } else if( Math.abs(1.0f - v) < 0.01f ) {
                v = 1.0f;
            }
            if( 0.0f <= v && v <= 1.0f ) { // OpenAL limits
                volume = v;
                al.alSourcef(alSource[0], AL.AL_GAIN, v);
                return true;
            }
        } finally {
            unlockContext();
        }
        return false;
    }

    @Override
    public final void flush() {
        if( !initialized || null == chosenFormat ) {
            return;
        }
        lockContext();
        try {
            // pauseImpl();
            stopImpl();
            al.alSourcei(alSource[0], AL.AL_BUFFER, 0); // explicit force zero buffer!
            dequeueBuffer( false /* wait */ );
            dequeueForceAll();
            if( alBufferNames.length != alFramesAvail.size() || alFramesPlaying.size() != 0 ) {
                throw new InternalError("XXX: "+this);
            }
            if( DEBUG ) {
                System.err.println(getThreadName()+": ALAudioSink: FLUSH playImpl "+(AL.AL_PLAYING == getSourceState())+", "+this);
            }
        } finally {
            unlockContext();
        }
    }

    @Override
    public final int getEnqueuedFrameCount() {
        return enqueuedFrameCount;
    }

    @Override
    public final int getFrameCount() {
        return null != alBufferNames ? alBufferNames.length : 0;
    }

    @Override
    public final int getQueuedFrameCount() {
        if( !initialized || null == chosenFormat ) {
            return 0;
        }
        return alFramesPlaying.size();
    }

    @Override
    public final int getFreeFrameCount() {
        if( !initialized || null == chosenFormat ) {
            return 0;
        }
        return alFramesAvail.size();
    }

    @Override
    public final int getQueuedByteCount() {
        if( !initialized || null == chosenFormat ) {
            return 0;
        }
        return alBufferBytesQueued;
    }

    @Override
    public final int getQueuedTime() {
        if( !initialized || null == chosenFormat ) {
            return 0;
        }
        return chosenFormat.getBytesDuration(alBufferBytesQueued);
    }

    @Override
    public final int getPTS() { return playingPTS; }

    private static final String toHexString(int v) { return "0x"+Integer.toHexString(v); }
    private static final String getThreadName() { return Thread.currentThread().getName(); }
}