/**
 *
 * Copyright 2003-2006 Jive Software.
 *
 * 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.
 */
package org.jivesoftware.smackx.jingle.mediaimpl.jmf;

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;

import javax.media.Codec;
import javax.media.Controller;
import javax.media.ControllerClosedEvent;
import javax.media.ControllerEvent;
import javax.media.ControllerListener;
import javax.media.Format;
import javax.media.MediaLocator;
import javax.media.NoProcessorException;
import javax.media.Processor;
import javax.media.UnsupportedPlugInException;
import javax.media.control.BufferControl;
import javax.media.control.PacketSizeControl;
import javax.media.control.TrackControl;
import javax.media.format.AudioFormat;
import javax.media.protocol.ContentDescriptor;
import javax.media.protocol.DataSource;
import javax.media.protocol.PushBufferDataSource;
import javax.media.protocol.PushBufferStream;
import javax.media.rtp.InvalidSessionAddressException;
import javax.media.rtp.RTPManager;
import javax.media.rtp.SendStream;
import javax.media.rtp.SessionAddress;

import org.jivesoftware.smackx.jingle.media.JingleMediaSession;

/**
 * An Easy to use Audio Channel implemented using JMF.
 * It sends and receives jmf for and from desired IPs and ports.
 * Also has a rport Symetric behavior for better NAT Traversal.
 * It send data from a defined port and receive data in the same port, making NAT binds easier.
 * <p/>
 * Send from portA to portB and receive from portB in portA.
 * <p/>
 * Sending
 * portA ---> portB
 * <p/>
 * Receiving
 * portB ---> portA
 * <p/>
 * <i>Transmit and Receive are interdependents. To receive you MUST trasmit. </i>
 *
 * @author Thiago Camargo
 */
public class AudioChannel {

        private static final Logger LOGGER = Logger.getLogger(AudioChannel.class.getName());
        
        private MediaLocator locator;
    private String localIpAddress;
    private String remoteIpAddress;
    private int localPort;
    private int portBase;
    private Format format;

    private Processor processor = null;
    private RTPManager rtpMgrs[];
    private DataSource dataOutput = null;
    private AudioReceiver audioReceiver;

    private List<SendStream> sendStreams = new ArrayList<SendStream>();

    private JingleMediaSession jingleMediaSession;

    private boolean started = false;

    /**
     * Creates an Audio Channel for a desired jmf locator. For instance: new MediaLocator("dsound://")
     *
     * @param locator         media locator
     * @param localIpAddress  local IP address
     * @param remoteIpAddress remote IP address
     * @param localPort       local port number
     * @param remotePort      remote port number
     * @param format          audio format
     */
    public AudioChannel(MediaLocator locator,
            String localIpAddress,
            String remoteIpAddress,
            int localPort,
            int remotePort,
            Format format, JingleMediaSession jingleMediaSession) {

        this.locator = locator;
        this.localIpAddress = localIpAddress;
        this.remoteIpAddress = remoteIpAddress;
        this.localPort = localPort;
        this.portBase = remotePort;
        this.format = format;
        this.jingleMediaSession = jingleMediaSession;
    }

    /**
     * Starts the transmission. Returns null if transmission started ok.
     * Otherwise it returns a string with the reason why the setup failed.
     * Starts receive also.
     *
     * @return result description
     */
    public synchronized String start() {
        if (started) return null;

        // Create a processor for the specified jmf locator
        String result = createProcessor();
        if (result != null) {
            started = false;
        }

        // Create an RTP session to transmit the output of the
        // processor to the specified IP address and port no.
        result = createTransmitter();
        if (result != null) {
            processor.close();
            processor = null;
            started = false;
        }
        else {
            started = true;
        }

        // Start the transmission
        processor.start();

        return null;
    }

    /**
     * Stops the transmission if already started.
     * Stops the receiver also.
     */
    public void stop() {
        if (!started) return;
        synchronized (this) {
            try {
                started = false;
                if (processor != null) {
                    processor.stop();
                    processor = null;

                    for (RTPManager rtpMgr : rtpMgrs) {
                        rtpMgr.removeReceiveStreamListener(audioReceiver);
                        rtpMgr.removeSessionListener(audioReceiver);
                        rtpMgr.removeTargets("Session ended.");
                        rtpMgr.dispose();
                    }

                    sendStreams.clear();

                }
            }
            catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    private String createProcessor() {
        if (locator == null)
            return "Locator is null";

        DataSource ds;

        try {
            ds = javax.media.Manager.createDataSource(locator);
        }
        catch (Exception e) {
            // Try JavaSound Locator as a last resort
            try {
                ds = javax.media.Manager.createDataSource(new MediaLocator("javasound://"));
            }
            catch (Exception ee) {
                return "Couldn't create DataSource";
            }
        }

        // Try to create a processor to handle the input jmf locator
        try {
            processor = javax.media.Manager.createProcessor(ds);
        }
        catch (NoProcessorException npe) {
            npe.printStackTrace();
            return "Couldn't create processor";
        }
        catch (IOException ioe) {
            ioe.printStackTrace();
            return "IOException creating processor";
        }

        // Wait for it to configure
        boolean result = waitForState(processor, Processor.Configured);
        if (!result){
            return "Couldn't configure processor";
        }
        
        // Get the tracks from the processor
        TrackControl[] tracks = processor.getTrackControls();

        // Do we have atleast one track?
        if (tracks == null || tracks.length < 1){
            return "Couldn't find tracks in processor";
        }

        // Set the output content descriptor to RAW_RTP
        // This will limit the supported formats reported from
        // Track.getSupportedFormats to only valid RTP formats.
        ContentDescriptor cd = new ContentDescriptor(ContentDescriptor.RAW_RTP);
        processor.setContentDescriptor(cd);

        Format supported[];
        Format chosen = null;
        boolean atLeastOneTrack = false;

        // Program the tracks.
        for (int i = 0; i < tracks.length; i++) {
            if (tracks[i].isEnabled()) {

                supported = tracks[i].getSupportedFormats();

                if (supported.length > 0) {
                    for (Format format : supported) {
                        if (format instanceof AudioFormat) {
                            if (this.format.matches(format))
                                chosen = format;
                        }
                    }
                    if (chosen != null) {
                        tracks[i].setFormat(chosen);
                        LOGGER.severe("Track " + i + " is set to transmit as: " + chosen);

                        if (tracks[i].getFormat() instanceof AudioFormat) {
                            int packetRate = 20;
                            PacketSizeControl pktCtrl = (PacketSizeControl) processor.getControl(PacketSizeControl.class.getName());
                            if (pktCtrl != null) {
                                try {
                                    pktCtrl.setPacketSize(getPacketSize(tracks[i].getFormat(), packetRate));
                                }
                                catch (IllegalArgumentException e) {
                                    pktCtrl.setPacketSize(80);
                                    // Do nothing
                                }
                            }

                            if (tracks[i].getFormat().getEncoding().equals(AudioFormat.ULAW_RTP)) {
                                Codec codec[] = new Codec[3];

                                codec[0] = new com.ibm.media.codec.audio.rc.RCModule();
                                codec[1] = new com.ibm.media.codec.audio.ulaw.JavaEncoder();
                                codec[2] = new com.sun.media.codec.audio.ulaw.Packetizer();
                                ((com.sun.media.codec.audio.ulaw.Packetizer) codec
                                        [2]).setPacketSize(160);

                                try {
                                    tracks[i].setCodecChain(codec);
                                }
                                catch (UnsupportedPlugInException e) {
                                    e.printStackTrace();
                                }
                            }

                        }

                        atLeastOneTrack = true;
                    }
                    else
                        tracks[i].setEnabled(false);
                }
                else
                    tracks[i].setEnabled(false);
            }
        }

        if (!atLeastOneTrack)
            return "Couldn't set any of the tracks to a valid RTP format";

        result = waitForState(processor, Controller.Realized);
        if (!result)
            return "Couldn't realize processor";

        // Get the output data source of the processor
        dataOutput = processor.getDataOutput();

        return null;
    }

    /**
     * Get the best packet size for a given codec and a codec rate
     *
     * @param codecFormat
     * @param milliseconds
     * @return the best packet size
     * @throws IllegalArgumentException
     */
    private int getPacketSize(Format codecFormat, int milliseconds) throws IllegalArgumentException {
        String encoding = codecFormat.getEncoding();
        if (encoding.equalsIgnoreCase(AudioFormat.GSM) ||
                encoding.equalsIgnoreCase(AudioFormat.GSM_RTP)) {
            return milliseconds * 4; // 1 byte per millisec
        }
        else if (encoding.equalsIgnoreCase(AudioFormat.ULAW) ||
                encoding.equalsIgnoreCase(AudioFormat.ULAW_RTP)) {
            return milliseconds * 8;
        }
        else {
            throw new IllegalArgumentException("Unknown codec type");
        }
    }

    /**
     * Use the RTPManager API to create sessions for each jmf
     * track of the processor.
     *
     * @return description
     */
    private String createTransmitter() {

        // Cheated.  Should have checked the type.
        PushBufferDataSource pbds = (PushBufferDataSource) dataOutput;
        PushBufferStream pbss[] = pbds.getStreams();

        rtpMgrs = new RTPManager[pbss.length];
        SessionAddress localAddr, destAddr;
        InetAddress ipAddr;
        SendStream sendStream;
        audioReceiver = new AudioReceiver(this, jingleMediaSession);
        int port;

        for (int i = 0; i < pbss.length; i++) {
            try {
                rtpMgrs[i] = RTPManager.newInstance();

                port = portBase + 2 * i;
                ipAddr = InetAddress.getByName(remoteIpAddress);

                localAddr = new SessionAddress(InetAddress.getByName(this.localIpAddress),
                        localPort);

                destAddr = new SessionAddress(ipAddr, port);

                rtpMgrs[i].addReceiveStreamListener(audioReceiver);
                rtpMgrs[i].addSessionListener(audioReceiver);

                BufferControl bc = (BufferControl) rtpMgrs[i].getControl("javax.media.control.BufferControl");
                if (bc != null) {
                    int bl = 160;
                    bc.setBufferLength(bl);
                }

                try {

                    rtpMgrs[i].initialize(localAddr);

                }
                catch (InvalidSessionAddressException e) {
                    // In case the local address is not allowed to read, we user another local address
                    SessionAddress sessAddr = new SessionAddress();
                    localAddr = new SessionAddress(sessAddr.getDataAddress(),
                            localPort);
                    rtpMgrs[i].initialize(localAddr);
                }

                rtpMgrs[i].addTarget(destAddr);

                LOGGER.severe("Created RTP session at " + localPort + " to: " + remoteIpAddress + " " + port);

                sendStream = rtpMgrs[i].createSendStream(dataOutput, i);

                sendStreams.add(sendStream);

                sendStream.start();

            }
            catch (Exception e) {
                e.printStackTrace();
                return e.getMessage();
            }
        }

        return null;
    }

    /**
     * Set transmit activity. If the active is true, the instance should trasmit.
     * If it is set to false, the instance should pause transmit.
     *
     * @param active active state
     */
    public void setTrasmit(boolean active) {
        for (SendStream sendStream : sendStreams) {
            try {
                if (active) {
                    sendStream.start();
                    LOGGER.fine("START");
                }
                else {
                    sendStream.stop();
                    LOGGER.fine("STOP");
                }
            }
            catch (IOException e) {
                e.printStackTrace();
            }

        }
    }

    /**
     * *************************************************************
     * Convenience methods to handle processor's state changes.
     * **************************************************************
     */

    private Integer stateLock = 0;
    private boolean failed = false;

    Integer getStateLock() {
        return stateLock;
    }

    void setFailed() {
        failed = true;
    }

    private synchronized boolean waitForState(Processor p, int state) {
        p.addControllerListener(new StateListener());
        failed = false;

        // Call the required method on the processor
        if (state == Processor.Configured) {
            p.configure();
        }
        else if (state == Processor.Realized) {
            p.realize();
        }

        // Wait until we get an event that confirms the
        // success of the method, or a failure event.
        // See StateListener inner class
        while (p.getState() < state && !failed) {
            synchronized (getStateLock()) {
                try {
                    getStateLock().wait();
                }
                catch (InterruptedException ie) {
                    return false;
                }
            }
        }

        return !failed;
    }

    /**
     * *************************************************************
     * Inner Classes
     * **************************************************************
     */

    class StateListener implements ControllerListener {

        public void controllerUpdate(ControllerEvent ce) {

            // If there was an error during configure or
            // realize, the processor will be closed
            if (ce instanceof ControllerClosedEvent)
                setFailed();

            // All controller events, send a notification
            // to the waiting thread in waitForState method.
            if (ce != null) {
                synchronized (getStateLock()) {
                    getStateLock().notifyAll();
                }
            }
        }
    }

    public static void main(String args[]) {

        InetAddress localhost;
        try {
            localhost = InetAddress.getLocalHost();

            AudioChannel audioChannel0 = new AudioChannel(new MediaLocator("javasound://8000"), localhost.getHostAddress(), localhost.getHostAddress(), 7002, 7020, new AudioFormat(AudioFormat.GSM_RTP), null);
            AudioChannel audioChannel1 = new AudioChannel(new MediaLocator("javasound://8000"), localhost.getHostAddress(), localhost.getHostAddress(), 7020, 7002, new AudioFormat(AudioFormat.GSM_RTP), null);

            audioChannel0.start();
            audioChannel1.start();

            try {
                Thread.sleep(5000);
            }
            catch (InterruptedException e) {
                e.printStackTrace();
            }

            audioChannel0.setTrasmit(false);
            audioChannel1.setTrasmit(false);

            try {
                Thread.sleep(5000);
            }
            catch (InterruptedException e) {
                e.printStackTrace();
            }

            audioChannel0.setTrasmit(true);
            audioChannel1.setTrasmit(true);

            try {
                Thread.sleep(5000);
            }
            catch (InterruptedException e) {
                e.printStackTrace();
            }

            audioChannel0.stop();
            audioChannel1.stop();

        }
        catch (UnknownHostException e) {
            e.printStackTrace();
        }

    }
}