MusicPerformer.java

package zenproject.meditation.android.sketch.music;

import android.media.MediaPlayer;

import com.juankysoriano.rainbow.core.event.RainbowInputController;
import com.novoda.notils.logger.simple.Log;

import zenproject.meditation.android.ContextRetriever;
import zenproject.meditation.android.R;
import zenproject.meditation.android.sketch.actions.StepPerformer;

public class MusicPerformer implements StepPerformer {
    private static final MediaPlayer RELEASED_MUSIC_PERFORMER = null;
    private static final float MUSIC_STEP = 0.005f;
    private static final float MIN_VOLUME = 0.05f;
    private MediaPlayer mediaPlayer;
    private final RainbowInputController rainbowInputController;
    private float volume = MIN_VOLUME;

    protected MusicPerformer(MediaPlayer mediaPlayer, RainbowInputController rainbowInputController) {
        this.mediaPlayer = mediaPlayer;
        this.rainbowInputController = rainbowInputController;
    }

    public static MusicPerformer newInstance(RainbowInputController rainbowInputController) {
        return new MusicPerformer(RELEASED_MUSIC_PERFORMER, rainbowInputController);
    }

    @Override
    public void init() {
        if (isMediaPlayerReleased()) {
            mediaPlayer = MediaPlayer.create(ContextRetriever.INSTANCE.getApplicationContext(), R.raw.zen);
            mediaPlayer.setVolume(volume, volume);
            mediaPlayer.setLooping(true);
        }
    }

    @Override
    public void doStep() {
        if (rainbowInputController.isScreenTouched()) {
            increaseVolume();
        } else {
            decreaseVolume();
        }
    }

    private void increaseVolume() {
        if (isPlaying()) {
            volume += MUSIC_STEP;
            volume = Math.min(1f, Math.max(MIN_VOLUME, volume));
            mediaPlayer.setVolume(volume, volume);
        }
    }

    private void decreaseVolume() {
        if (isPlaying()) {
            volume -= MUSIC_STEP;
            volume = Math.max(MIN_VOLUME, volume);
            mediaPlayer.setVolume(volume, volume);
        }
    }

    @Override
    public void reset() {
        volume = MIN_VOLUME;
        if (isMediaPlayerReleased()) {
            init();
            start();
        }
    }

    @Override
    public void disable() {
        stop();
    }

    @SuppressWarnings("PMD.CompareObjectsWithEquals")
    private boolean isMediaPlayerReleased() {
        return mediaPlayer == RELEASED_MUSIC_PERFORMER;
    }

    private void stop() {
        if (isPlaying()) {
            mediaPlayer.stop();
            releaseMediaPlayer();
        }
    }

    private boolean isPlaying() {
        if (isMediaPlayerReleased()) {
            return false;
        }

        try {
            return mediaPlayer.isPlaying();
        } catch (IllegalStateException e) {
            Log.e("Trying to access a mediaPlayer which is released or not initialised!!", e);
            return false;
        }
    }

    private void releaseMediaPlayer() {
        if (!isMediaPlayerReleased()) {
            mediaPlayer.release();
            mediaPlayer = RELEASED_MUSIC_PERFORMER;
        }
    }

    @Override
    public void enable() {
        reset();
    }

    private void start() {
        if (!isPlaying()) {
            mediaPlayer.start();
        }
    }
}