/* PulseAudioClip.java
   Copyright (C) 2008 Red Hat, Inc.

This file is part of IcedTea.

IcedTea is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as published by
the Free Software Foundation, version 2.

IcedTea 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 for more details.

You should have received a copy of the GNU General Public License
along with IcedTea; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version.
 */

package org.classpath.icedtea.pulseaudio;

import java.util.concurrent.Semaphore;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.DataLine;
import javax.sound.sampled.LineEvent;
import javax.sound.sampled.LineUnavailableException;

import org.classpath.icedtea.pulseaudio.Stream.WriteListener;

/**
 * 
 * This class contains code that is used by Clip, SourceDataLine and
 * TargetDataLine
 * 
 */
abstract class PulseAudioDataLine extends PulseAudioLine implements DataLine {

    protected static final int DEFAULT_BUFFER_SIZE = StreamBufferAttributes.SANE_DEFAULT;

    // override this to set the stream name
    protected String streamName;

    // true between start() and stop()
    protected boolean isStarted = false;

    // true between a started and an underflow callback
    protected boolean dataWritten = false;

    // true if a stream has been paused
    // protected boolean isPaused = false;

    protected AudioFormat[] supportedFormats = null;
    protected AudioFormat currentFormat = null;
    protected AudioFormat defaultFormat = null;
    protected boolean sendEvents = true;

    // the total number of frames played since this line was opened
    protected long framesSinceOpen = 0;

    protected EventLoop eventLoop = null;
    protected Semaphore semaphore = new Semaphore(0);
    protected Stream stream;
    boolean writeInterrupted = false;

    protected void open(AudioFormat format, int bufferSize)
            throws LineUnavailableException {

        if (isOpen()) {
            throw new IllegalStateException("Line is already open");
        }

        PulseAudioMixer mixer = PulseAudioMixer.getInstance();
        if (!mixer.isOpen()) {
            mixer.open();
        }

        eventLoop = EventLoop.getEventLoop();

        createStream(format);
        addStreamListeners();
        connect(null, bufferSize);
    }

    private void createStream(AudioFormat format)
            throws LineUnavailableException {

        for (AudioFormat myFormat : supportedFormats) {
            if (format.matches(myFormat)) {
                /*
                 * A few issues with format:
                 * 
                 * To match: SAME encoding: safe because its a java enum. SAME
                 * number of channels: safe because myFormat has specific
                 * values. SAME bits per sample (aka sampleSize) and bytes per
                 * frame (aka frameSize): safe because myFormat has specific
                 * values. SAME sample rate: _not_ safe because myFormat uses
                 * AudioSystem.NOT_SPECIFIED. SAME frame rate: safe because we
                 * _ignore_ it completely ;)
                 */

                float sampleRate = format.getSampleRate();
                if (sampleRate == (float) AudioSystem.NOT_SPECIFIED) {
                    /* pick a random sample rate */
                    sampleRate = 44100.0f;
                }

                String formatString = (String) myFormat
                        .getProperty(PulseAudioMixer.PULSEAUDIO_FORMAT_KEY);
                synchronized (eventLoop.threadLock) {

                    stream = new Stream(eventLoop.getContextPointer(),
                            streamName, Stream.Format.valueOf(formatString),
                            (int) sampleRate, myFormat.getChannels());

                }
                currentFormat = format;
                isOpen = true;
            }
        }

        if (!isOpen()) {
            throw new IllegalArgumentException("Invalid format");
        }

        // System.out.println("Stream " + stream + " created");

    }

    /**
     * This method adds the listeners used to find out when the stream has
     * connected/disconnected etc to the actual stream.
     */
    private void addStreamListeners() {
        Stream.StateListener openCloseListener = new Stream.StateListener() {

            @Override
            public void update() {
                synchronized (eventLoop.threadLock) {

                    /*
                     * Note the order: first we notify all the listeners, and
                     * then return. this means no race conditions when the
                     * listeners are removed before they get called by close
                     * 
                     * eg:
                     * 
                     * line.close(); line.removeLineListener(listener)
                     * 
                     * the listener is guaranteed to have run
                     */

                    if (stream.getState() == Stream.STATE_READY) {
                        if (sendEvents) {
                            fireLineEvent(new LineEvent(
                                    PulseAudioDataLine.this,
                                    LineEvent.Type.OPEN, framesSinceOpen));
                        }
                        semaphore.release();

                    } else if (stream.getState() == Stream.STATE_TERMINATED
                            || stream.getState() == Stream.STATE_FAILED) {
                        if (sendEvents) {
                            fireLineEvent((new LineEvent(
                                    PulseAudioDataLine.this,
                                    LineEvent.Type.CLOSE, framesSinceOpen)));
                        }
                        semaphore.release();
                    }
                }
            }
        };

        stream.addStateListener(openCloseListener);

        Stream.UnderflowListener stoppedListener = new Stream.UnderflowListener() {
            @Override
            public void update() {
                dataWritten = false;

                // always send a STOP event on an underflow (assumption:
                // an underflow can't happen while the stream is corked)
                fireLineEvent(new LineEvent(PulseAudioDataLine.this,
                        LineEvent.Type.STOP, framesSinceOpen));
            }
        };
        stream.addUnderflowListener(stoppedListener);

        Stream.PlaybackStartedListener startedListener = new Stream.PlaybackStartedListener() {
            @Override
            public void update() {
                if (!dataWritten) {
                    fireLineEvent(new LineEvent(PulseAudioDataLine.this,
                            LineEvent.Type.START, framesSinceOpen));
                    synchronized (this) {
                        PulseAudioDataLine.this.notifyAll();
                    }
                }
                dataWritten = true;

            }
        };

        stream.addPlaybackStartedListener(startedListener);

        WriteListener writeNotifier = new WriteListener() {

            @Override
            public void update() {
                synchronized (eventLoop.threadLock) {
                    eventLoop.threadLock.notifyAll();
                }
            }

        };
        stream.addWriteListener(writeNotifier);

        Stream.CorkListener corkListener = new Stream.CorkListener() {

            @Override
            public void update() {
                synchronized (eventLoop.threadLock) {
                    eventLoop.threadLock.notifyAll();
                }
            }

        };
        stream.addCorkListener(corkListener);
    }

    private void connect(Stream masterStream, int bufferSize)
            throws LineUnavailableException {

        try {
            synchronized (eventLoop.threadLock) {
                connectLine(bufferSize, masterStream);
            }
        } catch (LineUnavailableException e) {
            // error connecting to the server!
            // stream.removePlaybackStartedListener(startedListener);
            // stream.removeUnderflowListener(stoppedListener);
            // stream.removeStateListener(openCloseListener);
            stream.free();
            stream = null;
            throw e;

        }
        try {
            semaphore.acquire();
            synchronized (eventLoop.threadLock) {
                if (stream.getState() != Stream.STATE_READY) {
                    stream.disconnect();
                    stream.free();
                    throw new LineUnavailableException(
                            "unable to obtain a line");
                }
            }
        } catch (InterruptedException e) {
            throw new LineUnavailableException("unable to prepare stream");
        }
    }

    protected void open(AudioFormat format) throws LineUnavailableException {
        open(format, DEFAULT_BUFFER_SIZE);

    }

    @Override
    public void open() throws LineUnavailableException {
        assert (defaultFormat != null);
        open(defaultFormat, DEFAULT_BUFFER_SIZE);
    }

    @Override
    public void close() {

        if (!isOpen()) {
            // For whatever reason, we are being asked to close
            // a line that is not even open.
            return;
        }

        synchronized (eventLoop.threadLock) {
            stream.disconnect();
        }

        try {
            semaphore.acquire();
        } catch (InterruptedException e) {
            throw new RuntimeException("unable to prepare stream");
        }

        synchronized (eventLoop.threadLock) {
            stream.free();
        }

        super.close();

        isStarted = false;
    }

    void reconnectforSynchronization(Stream masterStream)
            throws LineUnavailableException {
        sendEvents = false;
        drain();

        synchronized (eventLoop.threadLock) {
            stream.disconnect();
        }
        try {
            semaphore.acquire();
        } catch (InterruptedException e) {
            throw new RuntimeException("unable to prepare stream");
        }

        createStream(getFormat());
        addStreamListeners();
        connect(masterStream, getBufferSize());

        sendEvents = true;
    }

    @Override
    public void start() {
        if (!isOpen()) {
            throw new IllegalStateException(
                    "Line must be open()ed before it can be start()ed");
        }

        if (isStarted) {
            return;

        }
        if (dataWritten && (!isStarted)) {
            fireLineEvent(new LineEvent(PulseAudioDataLine.this,
                    LineEvent.Type.START, framesSinceOpen));
        }

        Operation op;
        synchronized (eventLoop.threadLock) {
            op = stream.unCork();
        }

        op.waitForCompletion();
        op.releaseReference();
        synchronized (this) {
            this.notifyAll();
        }
        isStarted = true;

    }

    @Override
    public synchronized void stop() {
        if (!isOpen()) {
            // For some reason, we are being asked to stop a line
            // that isn't even open.
            return;
        }
        writeInterrupted = true;
        if (!isStarted) {
            return;
        }

        Operation op;
        synchronized (eventLoop.threadLock) {
            op = stream.cork();
            // if there are no data on the line when stop was called,
            // don't send a stop event
            if (dataWritten && (isStarted)) {
                fireLineEvent(new LineEvent(PulseAudioDataLine.this,
                        LineEvent.Type.STOP, framesSinceOpen));
            }
        }

        op.waitForCompletion();
        op.releaseReference();

        isStarted = false;
    }

    /*
     * TODO
     * 
     * http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4791152 :
     * 
     * a line is active in between calls to start() and stop(). In that sense,
     * active means that the line is ready to take or give data. Running is
     * tightly bound to data flow in the line. I.e. when you start a
     * SourceDataLine but never write data to it, the line should not be
     * running. This also means that a line should become not running on buffer
     * underrun/overflow.
     * 
     * 
     * HOWEVER, the javadocs say the opposite thing! (need help from the jck =
     * official spec)
     */
    @Override
    public boolean isActive() {
        return isStarted;
    }

    @Override
    public boolean isRunning() {
        return isStarted && dataWritten;
    }

    protected abstract void connectLine(int bufferSize, Stream masterStream)
            throws LineUnavailableException;

    public Stream getStream() {
        if (!isOpen()) {
            throw new IllegalStateException("Line must be open");
        }

        return stream;
    }

    @Override
    public int getBufferSize() {
        if (!isOpen()) {
            return DEFAULT_BUFFER_SIZE;
        }
        return stream.getBufferSize();
    }

    @Override
    public AudioFormat getFormat() {
        if (!isOpen()) {
            return defaultFormat;
        }
        return currentFormat;
    }

    @Override
    public float getLevel() {
        return AudioSystem.NOT_SPECIFIED;
    }

    /**
     * 
     * @param streamName
     *            the name of this audio stream
     */
    public void setName(String streamName) {
        if (isOpen()) {

            Operation o;
            synchronized (eventLoop.threadLock) {
                o = stream.setName(streamName);
            }
            o.waitForCompletion();
            o.releaseReference();

        }

        this.streamName = streamName;

    }

    /**
     * 
     * @return the name of this audio stream/clip
     */
    public String getName() {
        return streamName;
    }

    public int getBytesInBuffer() {
        Operation o;
        synchronized (eventLoop.threadLock) {
            o = stream.updateTimingInfo();
        }
        o.waitForCompletion();
        o.releaseReference();
        return stream.bytesInBuffer();
    }

}