/*******************************************************************************
 *     SDR Trunk 
 *     Copyright (C) 2014,2015 Dennis Sheirer
 *
 *     This program 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.
 *
 *     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 General Public License for more details.
 *
 *     You should have received a copy of the GNU General Public License
 *     along with this program.  If not, see <http://www.gnu.org/licenses/>
 ******************************************************************************/
package source.wave;

import channel.heartbeat.Heartbeat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import sample.ConversionUtils;
import sample.Listener;
import sample.real.RealBuffer;
import source.IControllableFileSource;
import source.IFrameLocationListener;
import source.RealSource;
import source.tuner.frequency.FrequencyChangeEvent;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.UnsupportedAudioFileException;
import java.io.File;
import java.io.IOException;
import java.util.Arrays;
import java.util.concurrent.ScheduledExecutorService;

public class RealWaveSource extends RealSource implements IControllableFileSource, AutoCloseable
{
    private final static Logger mLog = LoggerFactory.getLogger(RealWaveSource.class);

    private IFrameLocationListener mFrameLocationListener;
    private int mBytesPerFrame;
    private int mFrameCounter = 0;
    private long mFrequency = 0;
    private Listener<RealBuffer> mListener;
    private AudioInputStream mInputStream;
    private File mFile;

    public RealWaveSource(File file) throws IOException
    {
        mFile = file;
    }

    @Override
    public void setFrequencyChangeListener(Listener<FrequencyChangeEvent> listener)
    {
        //Not implemented
    }

    @Override
    public void removeFrequencyChangeListener()
    {
        //Not implemented
    }

    @Override
    public Listener<FrequencyChangeEvent> getFrequencyChangeListener()
    {
        //Not implemented
        return null;
    }

    /**
     * Not implemented
     */
    @Override
    public void setHeartbeatListener(Listener<Heartbeat> listener)
    {
    }

    /**
     * Not implemented
     */
    @Override
    public void removeHeartbeatListener()
    {
    }


    @Override
    public void reset()
    {
        stop();
        start(null);
    }


    @Override
    public void start(ScheduledExecutorService executor)
    {
        try
        {
            open();
        }
        catch(IOException | UnsupportedAudioFileException e)
        {
            mLog.error("Error starting real wave source", e);
        }
    }


    @Override
    public void stop()
    {
        try
        {
            close();
        }
        catch(IOException e)
        {
            mLog.error("Error stopping real wave source", e);
        }
    }


    @Override
    public long getFrameCount() throws IOException
    {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public int getSampleRate()
    {
        if(mInputStream != null)
        {
            return (int)mInputStream.getFormat().getSampleRate();
        }

        return 0;
    }

    /**
     * Returns the frequency set for this file.  Normally returns zero, but
     * the value can be set with setFrequency() method.
     */
    public long getFrequency()
    {
        return mFrequency;
    }

    /**
     * Changes the value returned from getFrequency() for this source.
     */
    public void setFrequency(long frequency)
    {
        mFrequency = frequency;
    }

    /**
     * Closes the source file
     */
    public void close() throws IOException
    {
        if(mInputStream != null)
        {
            mInputStream.close();
        }
        else
        {
            throw new IOException("Can't close wave source - was not opened");
        }

        mInputStream = null;
    }

    /**
     * Opens the source file for reading
     */
    public void open() throws IOException, UnsupportedAudioFileException
    {
        if(mInputStream == null)
        {
            mInputStream = AudioSystem.getAudioInputStream(mFile);
        }
        else
        {
            throw new IOException("Can't open wave source - is already opened");
        }


        AudioFormat format = mInputStream.getFormat();

        mBytesPerFrame = format.getFrameSize();

        if(format.getChannels() != 1 || format.getSampleSizeInBits() != 16)
        {
            throw new IOException("Unsupported Wave Format - EXPECTED: 1 " +
                "channel 16-bit samples FOUND: " +
                mInputStream.getFormat().getChannels() + " channels " +
                mInputStream.getFormat().getSampleSizeInBits() + "-bit samples");
        }
        
        /* Broadcast that we're at frame location 0 */
        broadcast(0);
    }

    /**
     * Reads the number of frames and sends a buffer to the listener
     */
    @Override
    public void next(int frames) throws IOException
    {
        next(frames, true);
    }

    /**
     * Reads the number of frames and optionally sends the buffer to the listener
     */
    public void next(int frames, boolean broadcast) throws IOException
    {
        if(mInputStream != null)
        {
            byte[] buffer = new byte[mBytesPerFrame * frames];

        	/* Fill the buffer with samples from the file */
            int samplesRead = mInputStream.read(buffer);

            mFrameCounter += samplesRead;

            broadcast(mFrameCounter);

            if(broadcast && mListener != null)
            {
                if(samplesRead < buffer.length)
                {
                    if(samplesRead == -1)
                    {
                        throw new IOException("End of recording");
                    }

                    buffer = Arrays.copyOf(buffer, samplesRead);
                }

                float[] samples = ConversionUtils
                    .convertFromSigned16BitSamples(buffer);

                mListener.receive(new RealBuffer(samples));
            }
        }
    }

    /**
     * Registers the listener to receive sample buffers as they are read from
     * the wave file
     */
    @Override
    public void setListener(Listener<RealBuffer> listener)
    {
        mListener = listener;
    }

    /**
     * Unregisters the listener from receiving sample buffers
     */
    public void removeListener(Listener<RealBuffer> listener)
    {
        mListener = null;
    }

    @Override
    public void dispose()
    {
        mListener = null;
    }

    @Override
    public File getFile()
    {
        return mFile;
    }

    private void broadcast(int byteLocation)
    {
        int frameLocation = (int)(byteLocation / mBytesPerFrame);

        if(mFrameLocationListener != null)
        {
            mFrameLocationListener.frameLocationUpdated(frameLocation);
        }
    }

    @Override
    public void setListener(IFrameLocationListener listener)
    {
        mFrameLocationListener = listener;
    }

    @Override
    public void removeListener(IFrameLocationListener listener)
    {
        mFrameLocationListener = null;
    }
}