// ****** Start Of Included File:theMixer.h ****** 
/* Audio Library for Teensy 3.X
 * Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
 *
 * Development of this audio library was funded by PJRC.COM, LLC by sales of
 * Teensy and Audio Adaptor boards.  Please support PJRC's efforts to develop
 * open source software by purchasing Teensy or other PJRC products.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice, development funding notice, and this permission
 * notice shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#ifndef themixer_h_
#define themixer_h_

#include <Arduino.h>
#include <AudioStream.h>

//#define AudioMixer4 AudioMixer<4>

#if defined(__ARM_ARCH_7EM__)

#define MULTI_UNITYGAIN 65536
#define MULTI_UNITYGAIN_F 65536.0f
#define MAX_GAIN 32767.0f
#define MIN_GAIN -32767.0f
#define MULT_DATA_TYPE int32_t

#elif defined(KINETISL)

#define MULTI_UNITYGAIN 256
#define MULTI_UNITYGAIN_F 256.0f
#define MAX_GAIN 127.0f
#define MIN_GAIN -127.0f
#define MULT_DATA_TYPE int16_t

#endif

template <int NN> class AudioMixer : public AudioStream
{
public:
  AudioMixer(void) : AudioStream(NN, inputQueueArray) {
    for (int i=0; i<NN; i++) multiplier[i] = MULTI_UNITYGAIN;
  } 
  virtual void update();
  
  /**
   * this sets the individual gains
   * @param channel
   * @param gain
   */
  void gain(unsigned int channel, float gain);
  /**
   * set all channels to specified gain
   * @param gain
   */
  void gain(float gain);

private:
  MULT_DATA_TYPE multiplier[NN];
  audio_block_t *inputQueueArray[NN];
};

// the following Forward declarations 
// must be defined when we use template 
// the compiler throws some warnings that should be errors otherwise

static int32_t signed_multiply_32x16b(int32_t a, uint32_t b); 
static int32_t signed_multiply_32x16t(int32_t a, uint32_t b);
static int32_t signed_saturate_rshift(int32_t val, int bits, int rshift);
static uint32_t pack_16b_16b(int32_t a, int32_t b);
static uint32_t signed_add_16_and_16(uint32_t a, uint32_t b);

// because of the template use applyGain and applyGainThenAdd functions
// must be in this file and NOT in cpp file
#if defined(__ARM_ARCH_7EM__)

  static void applyGain(int16_t *data, int32_t mult)
  {
    uint32_t *p = (uint32_t *)data;
    const uint32_t *end = (uint32_t *)(data + AUDIO_BLOCK_SAMPLES);

    do {
      uint32_t tmp32 = *p; // read 2 samples from *data
      int32_t val1 = signed_multiply_32x16b(mult, tmp32);
      int32_t val2 = signed_multiply_32x16t(mult, tmp32);
      val1 = signed_saturate_rshift(val1, 16, 0);
      val2 = signed_saturate_rshift(val2, 16, 0);
      *p++ = pack_16b_16b(val2, val1);
    } while (p < end);
  }

  static void applyGainThenAdd(int16_t *data, const int16_t *in, int32_t mult)
  {
    uint32_t *dst = (uint32_t *)data;
    const uint32_t *src = (uint32_t *)in;
    const uint32_t *end = (uint32_t *)(data + AUDIO_BLOCK_SAMPLES);

    if (mult == MULTI_UNITYGAIN) {
      do {
        uint32_t tmp32 = *dst;
        *dst++ =  signed_add_16_and_16(tmp32, *src++);
        tmp32 = *dst;
        *dst++ =  signed_add_16_and_16(tmp32, *src++);
      } while (dst < end);
    } else {
      do {
        uint32_t tmp32 = *src++; // read 2 samples from *data
        int32_t val1 =  signed_multiply_32x16b(mult, tmp32);
        int32_t val2 =  signed_multiply_32x16t(mult, tmp32);
        val1 =  signed_saturate_rshift(val1, 16, 0);
        val2 =  signed_saturate_rshift(val2, 16, 0);
        tmp32 =  pack_16b_16b(val2, val1);
        uint32_t tmp32b = *dst;
        *dst++ =  signed_add_16_and_16(tmp32, tmp32b);
      } while (dst < end);
    }
  }

#elif defined(KINETISL)

  static void applyGain(int16_t *data, int32_t mult)
  {
    const int16_t *end = data + AUDIO_BLOCK_SAMPLES;

    do {
      int32_t val = *data * mult;
      *data++ = signed_saturate_rshift(val, 16, 0);
    } while (data < end);
  }

  static void applyGainThenAdd(int16_t *dst, const int16_t *src, int32_t mult)
  {
    const int16_t *end = dst + AUDIO_BLOCK_SAMPLES;

    if (mult == MULTI_UNITYGAIN) {
      do {
        int32_t val = *dst + *src++;
        *dst++ = signed_saturate_rshift(val, 16, 0);
      } while (dst < end);
    } else {
      do {
        int32_t val = *dst + ((*src++ * mult) >> 8); // overflow possible??
        *dst++ = signed_saturate_rshift(val, 16, 0);
      } while (dst < end);
    }
  }
#endif

template <int NN> void AudioMixer<NN>::gain(unsigned int channel, float gain) {
  if (channel >= NN) return;
  if (gain > MAX_GAIN) gain = MAX_GAIN;
  else if (gain < MIN_GAIN) gain = MIN_GAIN;
  multiplier[channel] = gain * MULTI_UNITYGAIN_F; // TODO: proper roundoff?
}

template <int NN> void AudioMixer<NN>::gain(float gain) {
  for (int i = 0; i < NN; i++) {
    if (gain > MAX_GAIN) gain = MAX_GAIN;
    else if (gain < MIN_GAIN) gain = MIN_GAIN;
    multiplier[i] = gain * MULTI_UNITYGAIN_F; // TODO: proper roundoff?
  } 
}

template <int NN> void AudioMixer<NN>::update() {
  audio_block_t *in, *out=NULL;
  unsigned int channel;
  for (channel=0; channel < NN; channel++) {
    if (!out) {
      out = receiveWritable(channel);
      if (out) {
        int32_t mult = multiplier[channel];
        if (mult != MULTI_UNITYGAIN) applyGain(out->data, mult);
      }
    } else {
      in = receiveReadOnly(channel);
      if (in) {
        applyGainThenAdd(out->data, in->data, multiplier[channel]);
        release(in);
      }
    }
  }
  if (out) {
    transmit(out);
    release(out);
  }
}
// this class and function forces include 
// of functions applyGainThenAdd and applyGain used by the template
class DummyClass
{
  public:
    virtual void dummyFunction();
};
void DummyClass::dummyFunction() {
  applyGainThenAdd(0, 0, 0);
  applyGain(0,0);
    
}

#endif
// ****** End Of Included file:theMixer.h ******