/* PulseAudioTargetDataLine.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 javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioPermission;
import javax.sound.sampled.LineEvent;
import javax.sound.sampled.LineUnavailableException;
import javax.sound.sampled.TargetDataLine;

public class PulseAudioTargetDataLine extends PulseAudioDataLine implements
		TargetDataLine {

	/*
	 * This contains the data from the PulseAudio buffer that has since been
	 * dropped. If 20 bytes of a fragment of size 200 are read, the other 180
	 * are dumped in this
	 */
	byte[] fragmentBuffer;

	/*
	 * these are set to true only by the respective functions (flush(), drain())
	 * set to false only by read()
	 */
	boolean flushed = false;
	boolean drained = false;

	public PulseAudioTargetDataLine(EventLoop eventLoop, AudioFormat[] formats,
			AudioFormat defaultFormat) {
		supportedFormats = formats;
		this.eventLoop = eventLoop;
		this.defaultFormat = defaultFormat;
		this.currentFormat = defaultFormat;

	}

	@Override
	synchronized public void close() {
		/* check for permission to record audio */
		AudioPermission perm = new AudioPermission("record", null);
		perm.checkGuard(null);

		if (!isOpen) {
			throw new IllegalStateException(
					"Line cant be closed if it isnt open");
		}

		PulseAudioMixer parentMixer = PulseAudioMixer.getInstance();
		parentMixer.removeTargetLine(this);

		super.close();
	}

	@Override
	synchronized public void open(AudioFormat format, int bufferSize)
			throws LineUnavailableException {
		/* check for permission to record audio */
		AudioPermission perm = new AudioPermission("record", null);
		perm.checkGuard(null);

		if (isOpen) {
			throw new IllegalStateException("already open");
		}
		super.open(format, bufferSize);

		/* initialize all the member variables */
		framesSinceOpen = 0;
		fragmentBuffer = null;
		flushed = false;
		drained = false;

		/* add this open line to the mixer */
		PulseAudioMixer parentMixer = PulseAudioMixer.getInstance();
		parentMixer.addTargetLine(this);
	}

	@Override
	synchronized public void open(AudioFormat format)
			throws LineUnavailableException {
		open(format, DEFAULT_BUFFER_SIZE);
	}

	protected void connectLine(int bufferSize, Stream masterStream)
			throws LineUnavailableException {
		int fragmentSize = bufferSize / 10 > 500 ? bufferSize / 10 : 500;
		StreamBufferAttributes bufferAttributes = new StreamBufferAttributes(
				bufferSize, 0, 0, 0, fragmentSize);
		synchronized (eventLoop.threadLock) {
			stream.connectForRecording(Stream.DEFAULT_DEVICE, bufferAttributes);
		}
	}

	@Override
	public int read(byte[] data, int offset, int length) {

		/* check state and inputs */

		if (!isOpen) {
			throw new IllegalStateException("must call open() before read()");
		}

		int frameSize = currentFormat.getFrameSize();

		if (length % frameSize != 0) {
			throw new IllegalArgumentException(
					"amount of data to read does not represent an integral number of frames");
		}

		if (length < 0) {
			throw new IllegalArgumentException("length is negative");
		}

		if (length + offset > data.length) {
			throw new ArrayIndexOutOfBoundsException("index: "
					+ (length + offset) + " array size: " + data.length);
		}

		/* everything ok */

		int position = offset;
		int remainingLength = length;
		int sizeRead = 0;

		/* bytes read on each iteration of loop */
		int bytesRead;

		flushed = false;
		drained = false;

		/*
		 * to read, we first take stuff from the fragmentBuffer
		 */

		/* on first read() of the line, fragmentBuffer is null */
		if (fragmentBuffer != null) {
			synchronized (this) {

				boolean fragmentBufferSmaller = fragmentBuffer.length < length;
				int smallerBufferLength = Math.min(fragmentBuffer.length,
						length);
				System.arraycopy(fragmentBuffer, 0, data, position,
						smallerBufferLength);
				framesSinceOpen += smallerBufferLength
						/ currentFormat.getFrameSize();

				if (!fragmentBufferSmaller) {
					/*
					 * if fragment was larger, then we already have all the data
					 * we need. clean up the buffer before returning. Make a new
					 * fragmentBuffer from the remaining bytes
					 */
					int remainingBytesInFragment = (fragmentBuffer.length - length);
					byte[] newFragmentBuffer = new byte[remainingBytesInFragment];
					System.arraycopy(fragmentBuffer, length, newFragmentBuffer,
							0, newFragmentBuffer.length);
					fragmentBuffer = newFragmentBuffer;
					return length;
				}

				/* done with fragment buffer, remove it */
				bytesRead = smallerBufferLength;
				sizeRead += bytesRead;
				position += bytesRead;
				remainingLength -= bytesRead;
				fragmentBuffer = null;

			}
		}

		/*
		 * if we need to read more data, then we read from PulseAudio's buffer
		 */
		while (remainingLength != 0) {
			synchronized (this) {

				if (!isOpen || !isStarted) {
					return sizeRead;
				}

				if (flushed) {
					flushed = false;
					return sizeRead;
				}

				if (drained) {
					drained = false;
					return sizeRead;
				}

				byte[] currentFragment;
				synchronized (eventLoop.threadLock) {

					/* read a fragment, and drop it from the server */
					currentFragment = stream.peek();

					stream.drop();
					if (currentFragment == null) {
						System.out
								.println("DEBUG: PulseAudioTargetDataLine:read(): error in stream.peek()");
						continue;
					}

					bytesRead = Math.min(currentFragment.length,
							remainingLength);

					/*
					 * we read more than we required, save the rest of the data
					 * in the fragmentBuffer
					 */
					if (bytesRead < currentFragment.length) {
						/* allocate a buffer to store unsaved data */
						fragmentBuffer = new byte[currentFragment.length
								- bytesRead];

						/* copy over the unsaved data */
						System.arraycopy(currentFragment, bytesRead,
								fragmentBuffer, 0, currentFragment.length
										- bytesRead);
					}

					System.arraycopy(currentFragment, 0, data, position,
							bytesRead);

					sizeRead += bytesRead;
					position += bytesRead;
					remainingLength -= bytesRead;
					framesSinceOpen += bytesRead / currentFormat.getFrameSize();
				}
			}
		}

		// all the data should have been played by now
		assert (sizeRead == length);

		return sizeRead;

	}

	@Override
	public void drain() {

		if (!isOpen) {
			throw new IllegalStateException("must call open() before drain()");
		}

		synchronized (this) {
			drained = true;
		}

		// blocks when there is data on the line
		// http://www.jsresources.org/faq_audio.html#stop_drain_tdl
		while (true) {
			synchronized (this) {
				if (!isStarted || !isOpen) {
					break;
				}
			}
			try {
				Thread.sleep(100);
			} catch (InterruptedException e) {
				// do nothing
			}
		}

	}

	@Override
	public void flush() {
		if (!isOpen) {
			throw new IllegalStateException("Line must be open");
		}

		/* flush the buffer on pulseaudio's side */
		Operation operation;
		synchronized (eventLoop.threadLock) {
			operation = stream.flush();
		}
		operation.waitForCompletion();
		operation.releaseReference();

		synchronized (this) {
			flushed = true;
			/* flush the partial fragment we stored */
			fragmentBuffer = null;
		}

	}

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

		synchronized (eventLoop.threadLock) {
			return stream.getReableSize();
		}
	}

	public int getFramePosition() {
		return (int) framesSinceOpen;
	}

	public long getLongFramePosition() {
		return framesSinceOpen;
	}

	public long getMicrosecondPosition() {
		return (long) (framesSinceOpen / currentFormat.getFrameRate());
	}

	/*
	 * A TargetData starts when we ask it to and continues playing until we ask
	 * it to stop. There are no buffer underruns/overflows or anything so we
	 * will just fire the LineEvents manually
	 */

	@Override
	synchronized public void start() {
		super.start();

		fireLineEvent(new LineEvent(this, LineEvent.Type.START, framesSinceOpen));
	}

	@Override
	synchronized public void stop() {
		super.stop();

		fireLineEvent(new LineEvent(this, LineEvent.Type.STOP, framesSinceOpen));
	}

}