Audinaut-subsonic-app-android/app/src/main/java/net/nullsum/audinaut/audiofx/EqualizerController.java

/*
 This file is part of Subsonic.

 Subsonic 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, either version 3 of the License, or
 (at your option) any later version.

 Subsonic 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 Subsonic.  If not, see <http://www.gnu.org/licenses/>.

 Copyright 2011 (C) Sindre Mehus
 */
package net.nullsum.audinaut.audiofx;

import android.content.Context;
import android.media.audiofx.BassBoost;
import android.media.audiofx.Equalizer;
import android.util.Log;

import net.nullsum.audinaut.util.FileUtil;

import java.io.Serializable;

/**
 * Backward-compatible wrapper for {@link Equalizer}, which is API Level 9.
 *
 * @author Sindre Mehus
 * @version $Id$
 */
public class EqualizerController {

    private static final String TAG = EqualizerController.class.getSimpleName();

    private final Context context;
    private Equalizer equalizer;
    private BassBoost bass;
    private boolean loudnessAvailable = false;
    private LoudnessEnhancerController loudnessEnhancerController;
    private boolean released = false;
    private int audioSessionId = 0;

    public EqualizerController(Context context, int audioSessionId) {
        this.context = context;
        this.audioSessionId = audioSessionId;
        init();
    }

    private void init() {
        equalizer = new Equalizer(0, audioSessionId);
        bass = new BassBoost(0, audioSessionId);
        loudnessAvailable = true;
        loudnessEnhancerController = new LoudnessEnhancerController(audioSessionId);
    }

    public void saveSettings() {
        try {
            if (isAvailable()) {
                FileUtil.serialize(context, new EqualizerSettings(equalizer, bass, loudnessEnhancerController), "equalizer.dat");
            }
        } catch (Throwable x) {
            Log.w(TAG, "Failed to save equalizer settings.", x);
        }
    }

    public void loadSettings() {
        try {
            if (isAvailable()) {
                EqualizerSettings settings = FileUtil.deserialize(context, "equalizer.dat", EqualizerSettings.class);
                if (settings != null) {
                    settings.apply(equalizer, bass, loudnessEnhancerController);
                }
            }
        } catch (Throwable x) {
            Log.w(TAG, "Failed to load equalizer settings.", x);
        }
    }

    private boolean isAvailable() {
        return equalizer != null && bass != null;
    }

    public boolean isEnabled() {
        try {
            return isAvailable() && equalizer.getEnabled();
        } catch (Exception e) {
            return false;
        }
    }

    public void release() {
        if (isAvailable()) {
            released = true;
            equalizer.release();
            bass.release();
            if (loudnessEnhancerController != null && loudnessEnhancerController.isAvailable()) {
                loudnessEnhancerController.release();
            }
        }
    }

    public Equalizer getEqualizer() {
        if (released) {
            released = false;
            try {
                init();
            } catch (Throwable x) {
                equalizer = null;
                released = true;
                Log.w(TAG, "Failed to create equalizer.", x);
            }
        }
        return equalizer;
    }

    public BassBoost getBassBoost() {
        if (released) {
            released = false;
            try {
                init();
            } catch (Throwable x) {
                bass = null;
                Log.w(TAG, "Failed to create bass booster.", x);
            }
        }
        return bass;
    }

    public LoudnessEnhancerController getLoudnessEnhancerController() {
        if (loudnessAvailable && released) {
            released = false;
            try {
                init();
            } catch (Throwable x) {
                loudnessEnhancerController = null;
                Log.w(TAG, "Failed to create loudness enhancer.", x);
            }
        }
        return loudnessEnhancerController;
    }

    private static class EqualizerSettings implements Serializable {

        private short[] bandLevels;
        private boolean enabled;
        private short bass;
        private int loudness;

        public EqualizerSettings() {

        }

        public EqualizerSettings(Equalizer equalizer, BassBoost boost, LoudnessEnhancerController loudnessEnhancerController) {
            enabled = equalizer.getEnabled();
            bandLevels = new short[equalizer.getNumberOfBands()];
            for (short i = 0; i < equalizer.getNumberOfBands(); i++) {
                bandLevels[i] = equalizer.getBandLevel(i);
            }
            try {
                bass = boost.getRoundedStrength();
            } catch (Exception e) {
                bass = 0;
            }

            try {
                loudness = (int) loudnessEnhancerController.getGain();
            } catch (Exception e) {
                loudness = 0;
            }
        }

        public void apply(Equalizer equalizer, BassBoost boost, LoudnessEnhancerController loudnessController) {
            for (short i = 0; i < bandLevels.length; i++) {
                equalizer.setBandLevel(i, bandLevels[i]);
            }
            equalizer.setEnabled(enabled);
            if (bass != 0) {
                boost.setEnabled(true);
                boost.setStrength(bass);
            }
            if (loudness != 0) {
                loudnessController.enable();
                loudnessController.setGain(loudness);
            }
        }
    }
}