/*

 * Copyright (c) 1998, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.media.sound;

import java.util.ArrayList;

import java.util.List;

import javax.sound.midi.ControllerEventListener;

import javax.sound.midi.MetaEventListener;

import javax.sound.midi.MetaMessage;

import javax.sound.midi.ShortMessage;

import javax.sound.sampled.LineEvent;

import javax.sound.sampled.LineListener;

/**

 * EventDispatcher.  Used by various classes in the Java Sound implementation

 * to send events.

 *

 * @author David Rivas

 * @author Kara Kytle

 * @author Florian Bomers

 */

final class EventDispatcher implements Runnable {

    /**

     * time of inactivity until the auto closing clips

     * are closed

     */

    private static final int AUTO_CLOSE_TIME = 5000;

    /**

     * List of events

     */

    /**

     * Thread object for this EventDispatcher instance

     */

    private Thread thread = null;

    /*

     * support for auto-closing Clips

     */

    private final ArrayList<ClipInfo> autoClosingClips = new ArrayList<ClipInfo>();

    /*

     * support for monitoring data lines

     */

    private final ArrayList<LineMonitor> lineMonitors = new ArrayList<LineMonitor>();

    /**

     * Approximate interval between calls to LineMonitor.checkLine

     */

    static final int LINE_MONITOR_TIME = 400;

    /**

     * This start() method starts an event thread if one is not already active.

     */

    synchronized void start() {

        if(thread == null) {

            thread = JSSecurityManager.createThread(this,

                                                    "Java Sound Event Dispatcher",   // name

                                                    true,  // daemon

                                                    -1,    // priority

                                                    true); // doStart

        }

    }

    /**

     * Invoked when there is at least one event in the queue.

     * Implement this as a callback to process one event.

     */

    void processEvent(EventInfo eventInfo) {

        int count = eventInfo.getListenerCount();

        // process an LineEvent

        if (eventInfo.getEvent() instanceof LineEvent) {

            LineEvent event = (LineEvent) eventInfo.getEvent();

            if (Printer.debug) Printer.debug("Sending "+event+" to "+count+" listeners");

            for (int i = 0; i < count; i++) {

                try {

                    ((LineListener) eventInfo.getListener(i)).update(event);

                } catch (Throwable t) {

                    if (Printer.err) t.printStackTrace();

                }

            }

            return;

        }

        // process a MetaMessage

        if (eventInfo.getEvent() instanceof MetaMessage) {

            MetaMessage event = (MetaMessage)eventInfo.getEvent();

            for (int i = 0; i < count; i++) {

                try {

                    ((MetaEventListener) eventInfo.getListener(i)).meta(event);

                } catch (Throwable t) {

                    if (Printer.err) t.printStackTrace();

                }

            }

            return;

        }

        // process a Controller or Mode Event

        if (eventInfo.getEvent() instanceof ShortMessage) {

            ShortMessage event = (ShortMessage)eventInfo.getEvent();

            int status = event.getStatus();

            // Controller and Mode events have status byte 0xBc, where

            // c is the channel they are sent on.

            if ((status & 0xF0) == 0xB0) {

                for (int i = 0; i < count; i++) {

                    try {

                        ((ControllerEventListener) eventInfo.getListener(i)).controlChange(event);

                    } catch (Throwable t) {

                        if (Printer.err) t.printStackTrace();

                    }

                }

            }

            return;

        }

        Printer.err("Unknown event type: " + eventInfo.getEvent());

    }

    /**

     * Wait until there is something in the event queue to process.  Then

     * dispatch the event to the listeners.The entire method does not

     * need to be synchronized since this includes taking the event out

     * from the queue and processing the event. We only need to provide

     * exclusive access over the code where an event is removed from the

     *queue.

     */

    void dispatchEvents() {

        EventInfo eventInfo = null;

        synchronized (this) {

            // Wait till there is an event in the event queue.

            try {

                if (eventQueue.size() == 0) {

                    if (autoClosingClips.size() > 0 || lineMonitors.size() > 0) {

                        int waitTime = AUTO_CLOSE_TIME;

                        if (lineMonitors.size() > 0) {

                            waitTime = LINE_MONITOR_TIME;

                        }

                        wait(waitTime);

                    } else {

                        wait();

                    }

                }

            } catch (InterruptedException e) {

            }

            if (eventQueue.size() > 0) {

                // Remove the event from the queue and dispatch it to the listeners.

            }

        } // end of synchronized

        if (eventInfo != null) {

            processEvent(eventInfo);

        } else {

            if (autoClosingClips.size() > 0) {

                closeAutoClosingClips();

            }

            if (lineMonitors.size() > 0) {

                monitorLines();

            }

        }

    }

    /**

     * Queue the given event in the event queue.

     */

    private synchronized void postEvent(EventInfo eventInfo) {

        eventQueue.add(eventInfo);

        notifyAll();

    }

    /**

     * A loop to dispatch events.

     */

    public void run() {

        while (true) {

            try {

                dispatchEvents();

            } catch (Throwable t) {

                if (Printer.err) t.printStackTrace();

            }

        }

    }

    /**

     * Send audio and MIDI events.

     */

        if ((listeners == null)

            || (listeners.size() == 0)) {

            // nothing to do

            return;

        }

        start();

        EventInfo eventInfo = new EventInfo(event, listeners);

        postEvent(eventInfo);

    }

    /*

     * go through the list of registered auto-closing

     * Clip instances and close them, if appropriate

     *

     * This method is called in regular intervals

     */

    private void closeAutoClosingClips() {

        synchronized(autoClosingClips) {

            if (Printer.debug)Printer.debug("> EventDispatcher.closeAutoClosingClips ("+autoClosingClips.size()+" clips)");

            long currTime = System.currentTimeMillis();

            for (int i = autoClosingClips.size()-1; i >= 0 ; i--) {

                ClipInfo info = autoClosingClips.get(i);

                if (info.isExpired(currTime)) {

                    AutoClosingClip clip = info.getClip();

                    // sanity check

                    if (!clip.isOpen() || !clip.isAutoClosing()) {

                        if (Printer.debug)Printer.debug("EventDispatcher: removing clip "+clip+"  isOpen:"+clip.isOpen());

                        autoClosingClips.remove(i);

                    }

                    else if (!clip.isRunning() && !clip.isActive() && clip.isAutoClosing()) {

                        if (Printer.debug)Printer.debug("EventDispatcher: closing clip "+clip);

                        clip.close();

                    } else {

                        if (Printer.debug)Printer.debug("Doing nothing with clip "+clip+":");

                        if (Printer.debug)Printer.debug("  open="+clip.isOpen()+", autoclosing="+clip.isAutoClosing());

                        if (Printer.debug)Printer.debug("  isRunning="+clip.isRunning()+", isActive="+clip.isActive());

                    }

                } else {

                    if (Printer.debug)Printer.debug("EventDispatcher: clip "+info.getClip()+" not yet expired");

                }

            }

        }

        if (Printer.debug)Printer.debug("< EventDispatcher.closeAutoClosingClips ("+autoClosingClips.size()+" clips)");

    }

    private int getAutoClosingClipIndex(AutoClosingClip clip) {

        synchronized(autoClosingClips) {

            for (int i = autoClosingClips.size()-1; i >= 0; i--) {

                if (clip.equals(autoClosingClips.get(i).getClip())) {

                    return i;

                }

            }

        }

        return -1;

    }

    /**

     * called from auto-closing clips when one of their open() method is called

     */

    void autoClosingClipOpened(AutoClosingClip clip) {

        if (Printer.debug)Printer.debug("> EventDispatcher.autoClosingClipOpened ");

        int index = 0;

        synchronized(autoClosingClips) {

            index = getAutoClosingClipIndex(clip);

            if (index == -1) {

                if (Printer.debug)Printer.debug("EventDispatcher: adding auto-closing clip "+clip);

                autoClosingClips.add(new ClipInfo(clip));

            }

        }

        if (index == -1) {

            synchronized (this) {

                // this is only for the case that the first clip is set to autoclosing,

                // and it is already open, and nothing is done with it.

                // EventDispatcher.process() method would block in wait() and

                // never close this first clip, keeping the device open.

                notifyAll();

            }

        }

        if (Printer.debug)Printer.debug("< EventDispatcher.autoClosingClipOpened finished("+autoClosingClips.size()+" clips)");

    }

    /**

     * called from auto-closing clips when their closed() method is called

     */

    void autoClosingClipClosed(AutoClosingClip clip) {

        // nothing to do -- is removed from arraylist above

    }

    // ////////////////////////// Line Monitoring Support /////////////////// //

    /*

     * go through the list of registered line monitors

     * and call their checkLine method

     *

     * This method is called in regular intervals

     */

    private void monitorLines() {

        synchronized(lineMonitors) {

            if (Printer.debug)Printer.debug("> EventDispatcher.monitorLines ("+lineMonitors.size()+" monitors)");

            for (int i = 0; i < lineMonitors.size(); i++) {

                lineMonitors.get(i).checkLine();

            }

        }

        if (Printer.debug)Printer.debug("< EventDispatcher.monitorLines("+lineMonitors.size()+" monitors)");

    }

    /**

     * Add this LineMonitor instance to the list of monitors

     */

    void addLineMonitor(LineMonitor lm) {

        if (Printer.trace)Printer.trace("> EventDispatcher.addLineMonitor("+lm+")");

        synchronized(lineMonitors) {

            if (lineMonitors.indexOf(lm) >= 0) {

                if (Printer.trace)Printer.trace("< EventDispatcher.addLineMonitor finished -- this monitor already exists!");

                return;

            }

            if (Printer.debug)Printer.debug("EventDispatcher: adding line monitor "+lm);

            lineMonitors.add(lm);

        }

        synchronized (this) {

            // need to interrupt the infinite wait()

            notifyAll();

        }

        if (Printer.debug)Printer.debug("< EventDispatcher.addLineMonitor finished -- now ("+lineMonitors.size()+" monitors)");

    }

    /**

     * Remove this LineMonitor instance from the list of monitors

     */

    void removeLineMonitor(LineMonitor lm) {

        if (Printer.trace)Printer.trace("> EventDispatcher.removeLineMonitor("+lm+")");

        synchronized(lineMonitors) {

            if (lineMonitors.indexOf(lm) < 0) {

                if (Printer.trace)Printer.trace("< EventDispatcher.removeLineMonitor finished -- this monitor does not exist!");

                return;

            }

            if (Printer.debug)Printer.debug("EventDispatcher: removing line monitor "+lm);

            lineMonitors.remove(lm);

        }

        if (Printer.debug)Printer.debug("< EventDispatcher.removeLineMonitor finished -- now ("+lineMonitors.size()+" monitors)");

    }

    // /////////////////////////////////// INNER CLASSES ////////////////////////////////////////// //

    /**

     * Container for an event and a set of listeners to deliver it to.

     */

    private class EventInfo {

        private final Object event;

        private final Object[] listeners;

        /**

         * Create a new instance of this event Info class

         * @param event the event to be dispatched

         * @param listeners listener list; will be copied

         */

            this.event = event;

            this.listeners = listeners.toArray();

        }

        Object getEvent() {

            return event;

        }

        int getListenerCount() {

            return listeners.length;

        }

        Object getListener(int index) {

            return listeners[index];

        }

    } // class EventInfo

    /**

     * Container for a clip with its expiration time

     */

    private class ClipInfo {

        private final AutoClosingClip clip;

        private final long expiration;

        /**

         * Create a new instance of this clip Info class

         */

        ClipInfo(AutoClosingClip clip) {

            this.clip = clip;

            this.expiration = System.currentTimeMillis() + AUTO_CLOSE_TIME;

        }

        AutoClosingClip getClip() {

            return clip;

        }

        boolean isExpired(long currTime) {

            return currTime > expiration;

        }

    } // class ClipInfo

    /**

     * Interface that a class that wants to get regular

     * line monitor events implements

     */

    interface LineMonitor {

        /**

         * Called by event dispatcher in regular intervals

         */

        public void checkLine();

    }

} // class EventDispatcher