/*
 * Catroid: An on-device visual programming system for Android devices
 * Copyright (C) 2010-2016 The Catrobat Team
 * (<http://developer.catrobat.org/credits>)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * An additional term exception under section 7 of the GNU Affero
 * General Public License, version 3, is available at
 * http://developer.catrobat.org/license_additional_term
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.catrobat.catroid.formulaeditor;

import android.os.Handler;
import android.util.Log;

import org.catrobat.catroid.soundrecorder.SoundRecorder;

import java.io.IOException;
import java.util.ArrayList;

public final class SensorLoudness {

	private static final int UPDATE_INTERVAL = 50;
	private static final double SCALE_RANGE = 100d;
	private static final double MAX_AMP_VALUE = 32767d;
	private static final String TAG = SensorLoudness.class.getSimpleName();
	private static SensorLoudness instance = null;
	private ArrayList<SensorCustomEventListener> listenerList = new ArrayList<SensorCustomEventListener>();

	private SoundRecorder recorder = null;
	private Handler handler;
	private float lastValue = 0f;

	private SensorLoudness() {
		handler = new Handler();
		recorder = new SoundRecorder("/dev/null");
	}

	Runnable statusChecker = new Runnable() {
		@Override
		public void run() {
			float[] loudness = new float[1];
			loudness[0] = (float) (SCALE_RANGE / MAX_AMP_VALUE) * recorder.getMaxAmplitude();
			if (lastValue != loudness[0] && loudness[0] != 0f) {
				lastValue = loudness[0];
				SensorCustomEvent event = new SensorCustomEvent(Sensors.LOUDNESS, loudness);
				for (SensorCustomEventListener listener : listenerList) {
					listener.onCustomSensorChanged(event);
				}
			}
			handler.postDelayed(statusChecker, UPDATE_INTERVAL);
		}
	};

	public static SensorLoudness getSensorLoudness() {
		if (instance == null) {
			instance = new SensorLoudness();
		}
		return instance;
	}

	public synchronized boolean registerListener(SensorCustomEventListener listener) {
		if (listenerList.contains(listener)) {
			return true;
		}
		listenerList.add(listener);
		if (!recorder.isRecording()) {
			try {
				recorder.start();
				statusChecker.run();
			} catch (IOException iOException) {
				Log.d(TAG, "Could not start recorder", iOException);
				listenerList.remove(listener);
				recorder = new SoundRecorder("/dev/null");
				return false;
			} catch (RuntimeException runtimeException) {
				Log.d(TAG, "Could not start recorder", runtimeException);
				listenerList.remove(listener);
				recorder = new SoundRecorder("/dev/null");
				return false;
			}
		}
		return true;
	}

	public synchronized void unregisterListener(SensorCustomEventListener listener) {
		if (listenerList.contains(listener)) {
			listenerList.remove(listener);
			if (listenerList.size() == 0) {
				handler.removeCallbacks(statusChecker);
				if (recorder.isRecording()) {
					try {
						recorder.stop();
					} catch (IOException iOException) {
						// ignored, nothing we can do
						Log.d(TAG, "Could not stop recorder", iOException);
					}
					recorder = new SoundRecorder("/dev/null");
				}
				lastValue = 0f;
			}
		}
	}
}