/*
  AudioOutputMixer
  Simple mixer which can combine multiple inputs to a single output stream
  
  Copyright (C) 2017  Earle F. Philhower, III

  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/>.
*/

#ifndef _AUDIOOUTPUTMIXER_H
#define _AUDIOOUTPUTMIXER_H

#include "AudioOutput.h"

class AudioOutputMixer;


// The output stub exported by the mixer for use by the generator
class AudioOutputMixerStub : public AudioOutput
{
  public:
    AudioOutputMixerStub(AudioOutputMixer *sink, int id);
    virtual ~AudioOutputMixerStub() override;
    virtual bool SetRate(int hz) override;
    virtual bool SetBitsPerSample(int bits) override;
    virtual bool SetChannels(int channels) override;
    virtual bool begin() override;
    virtual bool ConsumeSample(int16_t sample[2]) override;
    virtual bool stop() override;

  protected:
    AudioOutputMixer *parent;
    int id;
};

// Single mixer object per output
class AudioOutputMixer : public AudioOutput
{
  public:
    AudioOutputMixer(int samples, AudioOutput *sink);
    virtual ~AudioOutputMixer() override;
    virtual bool SetRate(int hz) override;
    virtual bool SetBitsPerSample(int bits) override;
    virtual bool SetChannels(int channels) override;
    virtual bool begin() override;
    virtual bool ConsumeSample(int16_t sample[2]) override;
    virtual bool stop() override;
    virtual bool loop() override; // Send all existing samples we can to I2S

    AudioOutputMixerStub *NewInput(); // Get a new stub to pass to a generator

  // Stub called functions
  friend class AudioOutputMixerStub;
  private:
    void RemoveInput(int id);
    bool SetRate(int hz, int id);
    bool SetBitsPerSample(int bits, int id);
    bool SetChannels(int channels, int id);
    bool begin(int id);
    bool ConsumeSample(int16_t sample[2], int id);
    bool stop(int id);

  protected:
    enum { maxStubs = 8 };
    AudioOutput *sink;
    bool sinkStarted;
    int16_t buffSize;
    int32_t *leftAccum;
    int32_t *rightAccum;
    bool stubAllocated[maxStubs];
    bool stubRunning[maxStubs];
    int16_t writePtr[maxStubs]; // Array of pointers for allocated stubs
    int16_t readPtr;
};

#endif