/**
 * File: AudioPlayer.java
 * Author: Brian Borowski
 * Date created: August 1, 2011
 * Date last modified: January 21, 2013
 */
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;

import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.Clip;
import javax.sound.sampled.DataLine;
import javax.sound.sampled.LineUnavailableException;
import javax.sound.sampled.Mixer;
import javax.sound.sampled.UnsupportedAudioFileException;

public class AudioPlayer implements Runnable {
    public static final int
        LAUNCH_MISSILE = 0,
        SPACESHIP_IMPACT = 1,
        LAUNCHER_IMPACT = 2;

    private final Clip[] clips = new Clip[3];
    private final boolean[] play = new boolean[3];
    private Thread thread;
    private boolean isRunning;
    private static AudioPlayer audioPlayer = null;

    private AudioPlayer() {
        // We use the Java Sound Audio Engine because the default JApplet
        // AudioClip and even Direct Audio Device sometimes skip playing a sound.
        // The Java Sound Audio Engine is quite slow, so it will be run from
        // within a separate thread to keep the animation responsive.
        Mixer mixer = null;
        final Mixer.Info[] mixers = AudioSystem.getMixerInfo();
        for (int i = 0; i < mixers.length; i++) {
            if ("Primary Sound Driver".equals(mixers[i].getName())) {
                mixer = AudioSystem.getMixer(mixers[i]);
            }
        }

        clips[LAUNCH_MISSILE] = loadClip(mixer, "audio/launch_missile.wav");
        clips[SPACESHIP_IMPACT] = loadClip(mixer, "audio/spaceship_impact.wav");
        clips[LAUNCHER_IMPACT] = loadClip(mixer, "audio/launcher_impact.wav");
        start();
    }

    public static AudioPlayer getInstance() {
        if (audioPlayer == null) {
            audioPlayer = new AudioPlayer();
        }
        return audioPlayer;
    }

    private void start() {
        isRunning = true;
        thread = new Thread(this);
        thread.start();
    }

    public static void stop() {
        try {
            audioPlayer.isRunning = false;
            if (audioPlayer.thread != null) {
                audioPlayer.thread.join();
            }
        } catch (final InterruptedException ie) { }
        audioPlayer = null;
    }

    public void run() {
        while (isRunning) {
            final long startTime = System.currentTimeMillis();

            boolean stopped = false;
            synchronized (this) {
                for (int i = LAUNCH_MISSILE; i <= LAUNCHER_IMPACT; i++) {
                    if (play[i] && clips[i].isRunning()) {
                        clips[i].stop();
                        stopped = true;
                    }
                }
                if (stopped) {
                    try {
                        // This is a hack. If I don't give the Clip some time
                        // to stop, the sound is garbled the next time it is
                        // played.
                        Thread.sleep(1);
                    } catch (final InterruptedException ie) { }
                }
                for (int i = LAUNCH_MISSILE; i <= LAUNCHER_IMPACT; i++) {
                    if (play[i]) {
                        clips[i].setFramePosition(0);
                        clips[i].start();
                        play[i] = false;
                    }
                }
            }

            long sleepTime = 10 - (System.currentTimeMillis() - startTime);
            if (sleepTime < 0) {
                sleepTime = 10;
            }
            try {
                // Millisecond resolution sleep
                Thread.sleep(sleepTime);
            } catch (final InterruptedException ie) { }
        }
    }

    public synchronized void play(final int clipIndex) {
        play[clipIndex] = true;
    }

    private static Clip loadClip(final Mixer mixer, final String filename) {
        URL url = AudioPlayer.class.getResource(filename);
        if (url == null) {
            try {
                final File file = new File(filename);
                if (file.canRead()) url = file.toURI().toURL();
            } catch (final IllegalArgumentException iae) {
                // URL is not absolute.
            } catch (final MalformedURLException murle) {
                // Not a URL.
            }
        }

        Clip clip = null;
        if (url == null) {
            System.err.println("Audio file " + filename + " not found.");
            return clip;
        }

        try {
            final AudioInputStream audioInputStream =
                    AudioSystem.getAudioInputStream(url);
            if (mixer != null) {
                final DataLine.Info info =
                    new DataLine.Info(Clip.class, audioInputStream.getFormat());
                clip = (Clip)mixer.getLine(info);
            } else {
                clip = AudioSystem.getClip();
            }
            clip.open(audioInputStream);
        } catch (final UnsupportedAudioFileException uafe) {
        } catch (final IOException ioe) {
        } catch (final LineUnavailableException lue) {
        }
        return clip;
    }
}