/*
 * Copyright © 2014 Mozilla Foundation
 *
 * This program is made available under an ISC-style license.  See the
 * accompanying file LICENSE for details.
 */
#ifndef NOMINMAX
#define NOMINMAX
#endif // NOMINMAX

#include <algorithm>
#include <cmath>
#include <cassert>
#include <cstring>
#include <cstddef>
#include <cstdio>
#include "cubeb_resampler.h"
#include "cubeb-speex-resampler.h"
#include "cubeb_resampler_internal.h"
#include "cubeb_utils.h"

int
to_speex_quality(cubeb_resampler_quality q)
{
  switch(q) {
  case CUBEB_RESAMPLER_QUALITY_VOIP:
    return SPEEX_RESAMPLER_QUALITY_VOIP;
  case CUBEB_RESAMPLER_QUALITY_DEFAULT:
    return SPEEX_RESAMPLER_QUALITY_DEFAULT;
  case CUBEB_RESAMPLER_QUALITY_DESKTOP:
    return SPEEX_RESAMPLER_QUALITY_DESKTOP;
  default:
    assert(false);
    return 0XFFFFFFFF;
  }
}

uint32_t min_buffered_audio_frame(uint32_t sample_rate)
{
  return sample_rate / 20;
}

template<typename T>
passthrough_resampler<T>::passthrough_resampler(cubeb_stream * s,
                                                cubeb_data_callback cb,
                                                void * ptr,
                                                uint32_t input_channels,
                                                uint32_t sample_rate)
  : processor(input_channels)
  , stream(s)
  , data_callback(cb)
  , user_ptr(ptr)
  , sample_rate(sample_rate)
{
}

template<typename T>
long passthrough_resampler<T>::fill(void * input_buffer, long * input_frames_count,
                                    void * output_buffer, long output_frames)
{
  if (input_buffer) {
    assert(input_frames_count);
  }
  assert((input_buffer && output_buffer) ||
         (output_buffer && !input_buffer && (!input_frames_count || *input_frames_count == 0)) ||
         (input_buffer && !output_buffer && output_frames == 0));

  // When we have no pending input data and exactly as much input
  // as output data, we don't need to copy it into the internal buffer
  // and can directly forward it to the callback.
  void * in_buf = input_buffer;
  unsigned long pop_input_count = 0u;
  if (input_buffer && !output_buffer) {
      output_frames = *input_frames_count;
  } else if(input_buffer) {
    if (internal_input_buffer.length() != 0 ||
        *input_frames_count < output_frames) {
      // If we have pending input data left and have to first append the input
      // so we can pass it as one pointer to the callback. Or this is a glitch.
      // It can happen when system's performance is poor. Audible silence is
      // being pushed at the end of the short input buffer. An improvement for
      // the future is to resample to the output number of frames, when that happens.
      internal_input_buffer.push(static_cast<T*>(input_buffer),
                                 frames_to_samples(*input_frames_count));
      if (internal_input_buffer.length() < frames_to_samples(output_frames)) {
        // This is unxpected but it can happen when a glitch occurs. Fill the
        // buffer with silence. First keep the actual number of input samples
        // used without the silence.
        pop_input_count = internal_input_buffer.length();
        internal_input_buffer.push_silence(
            frames_to_samples(output_frames) - internal_input_buffer.length());
      } else {
        pop_input_count = frames_to_samples(output_frames);
      }
      in_buf = internal_input_buffer.data();
    } else if(*input_frames_count > output_frames) {
      // In this case we have more input that we need output and
      // fill the overflowing input into internal_input_buffer
      // Since we have no other pending data, we can nonetheless
      // pass the current input data directly to the callback
      assert(pop_input_count == 0);
      unsigned long samples_off = frames_to_samples(output_frames);
      internal_input_buffer.push(static_cast<T*>(input_buffer) + samples_off,
                                 frames_to_samples(*input_frames_count - output_frames));
    }
  }

  long rv = data_callback(stream, user_ptr, in_buf, output_buffer, output_frames);

  if (input_buffer) {
    if (pop_input_count) {
      internal_input_buffer.pop(nullptr, pop_input_count);
      *input_frames_count = samples_to_frames(pop_input_count);
    } else {
      *input_frames_count = output_frames;
    }
    drop_audio_if_needed();
  }

  return rv;
}

// Explicit instantiation of template class.
template class passthrough_resampler<float>;
template class passthrough_resampler<short>;

template<typename T, typename InputProcessor, typename OutputProcessor>
cubeb_resampler_speex<T, InputProcessor, OutputProcessor>
  ::cubeb_resampler_speex(InputProcessor * input_processor,
                          OutputProcessor * output_processor,
                          cubeb_stream * s,
                          cubeb_data_callback cb,
                          void * ptr)
  : input_processor(input_processor)
  , output_processor(output_processor)
  , stream(s)
  , data_callback(cb)
  , user_ptr(ptr)
{
  if (input_processor && output_processor) {
    fill_internal = &cubeb_resampler_speex::fill_internal_duplex;
  }  else if (input_processor) {
    fill_internal = &cubeb_resampler_speex::fill_internal_input;
  }  else if (output_processor) {
    fill_internal = &cubeb_resampler_speex::fill_internal_output;
  }
}

template<typename T, typename InputProcessor, typename OutputProcessor>
cubeb_resampler_speex<T, InputProcessor, OutputProcessor>
  ::~cubeb_resampler_speex()
{ }

template<typename T, typename InputProcessor, typename OutputProcessor>
long
cubeb_resampler_speex<T, InputProcessor, OutputProcessor>
::fill(void * input_buffer, long * input_frames_count,
       void * output_buffer, long output_frames_needed)
{
  /* Input and output buffers, typed */
  T * in_buffer = reinterpret_cast<T*>(input_buffer);
  T * out_buffer = reinterpret_cast<T*>(output_buffer);
  return (this->*fill_internal)(in_buffer, input_frames_count,
                                out_buffer, output_frames_needed);
}

template<typename T, typename InputProcessor, typename OutputProcessor>
long
cubeb_resampler_speex<T, InputProcessor, OutputProcessor>
::fill_internal_output(T * input_buffer, long * input_frames_count,
                       T * output_buffer, long output_frames_needed)
{
  assert(!input_buffer && (!input_frames_count || *input_frames_count == 0) &&
         output_buffer && output_frames_needed);

  if (!draining) {
    long got = 0;
    T * out_unprocessed = nullptr;
    long output_frames_before_processing = 0;

    /* fill directly the input buffer of the output processor to save a copy */
    output_frames_before_processing =
      output_processor->input_needed_for_output(output_frames_needed);

    out_unprocessed =
      output_processor->input_buffer(output_frames_before_processing);

    got = data_callback(stream, user_ptr,
                        nullptr, out_unprocessed,
                        output_frames_before_processing);

    if (got < output_frames_before_processing) {
      draining = true;

      if (got < 0) {
        return got;
      }
    }

    output_processor->written(got);
  }

  /* Process the output. If not enough frames have been returned from the
  * callback, drain the processors. */
  return output_processor->output(output_buffer, output_frames_needed);
}

template<typename T, typename InputProcessor, typename OutputProcessor>
long
cubeb_resampler_speex<T, InputProcessor, OutputProcessor>
::fill_internal_input(T * input_buffer, long * input_frames_count,
                      T * output_buffer, long /*output_frames_needed*/)
{
  assert(input_buffer && input_frames_count && *input_frames_count &&
         !output_buffer);

  /* The input data, after eventual resampling. This is passed to the callback. */
  T * resampled_input = nullptr;
  uint32_t resampled_frame_count = input_processor->output_for_input(*input_frames_count);

  /* process the input, and present exactly `output_frames_needed` in the
  * callback. */
  input_processor->input(input_buffer, *input_frames_count);

  size_t frames_resampled = 0;
  resampled_input = input_processor->output(resampled_frame_count, &frames_resampled);
  *input_frames_count = frames_resampled;

  long got = data_callback(stream, user_ptr,
                           resampled_input, nullptr, resampled_frame_count);

  /* Return the number of initial input frames or part of it.
  * Since output_frames_needed == 0 in input scenario, the only
  * available number outside resampler is the initial number of frames. */
  return (*input_frames_count) * (got / resampled_frame_count);
}

template<typename T, typename InputProcessor, typename OutputProcessor>
long
cubeb_resampler_speex<T, InputProcessor, OutputProcessor>
::fill_internal_duplex(T * in_buffer, long * input_frames_count,
                       T * out_buffer, long output_frames_needed)
{
  if (draining) {
    // discard input and drain any signal remaining in the resampler.
    return output_processor->output(out_buffer, output_frames_needed);
  }

  /* The input data, after eventual resampling. This is passed to the callback. */
  T * resampled_input = nullptr;
  /* The output buffer passed down in the callback, that might be resampled. */
  T * out_unprocessed = nullptr;
  long output_frames_before_processing = 0;
  /* The number of frames returned from the callback. */
  long got = 0;

  /* We need to determine how much frames to present to the consumer.
   * - If we have a two way stream, but we're only resampling input, we resample
   * the input to the number of output frames.
   * - If we have a two way stream, but we're only resampling the output, we
   * resize the input buffer of the output resampler to the number of input
   * frames, and we resample it afterwards.
   * - If we resample both ways, we resample the input to the number of frames
   * we would need to pass down to the consumer (before resampling the output),
   * get the output data, and resample it to the number of frames needed by the
   * caller. */

  output_frames_before_processing =
    output_processor->input_needed_for_output(output_frames_needed);
   /* fill directly the input buffer of the output processor to save a copy */
  out_unprocessed =
    output_processor->input_buffer(output_frames_before_processing);

  if (in_buffer) {
    /* process the input, and present exactly `output_frames_needed` in the
    * callback. */
    input_processor->input(in_buffer, *input_frames_count);

    size_t frames_resampled = 0;
    resampled_input =
      input_processor->output(output_frames_before_processing, &frames_resampled);
    *input_frames_count = frames_resampled;
  } else {
    resampled_input = nullptr;
  }

  got = data_callback(stream, user_ptr,
                      resampled_input, out_unprocessed,
                      output_frames_before_processing);

  if (got < output_frames_before_processing) {
    draining = true;

    if (got < 0) {
      return got;
    }
  }

  output_processor->written(got);

  input_processor->drop_audio_if_needed();

  /* Process the output. If not enough frames have been returned from the
   * callback, drain the processors. */
  got = output_processor->output(out_buffer, output_frames_needed);

  output_processor->drop_audio_if_needed();

  return got;
}

/* Resampler C API */

cubeb_resampler *
cubeb_resampler_create(cubeb_stream * stream,
                       cubeb_stream_params * input_params,
                       cubeb_stream_params * output_params,
                       unsigned int target_rate,
                       cubeb_data_callback callback,
                       void * user_ptr,
                       cubeb_resampler_quality quality)
{
  cubeb_sample_format format;

  assert(input_params || output_params);

  if (input_params) {
    format = input_params->format;
  } else {
    format = output_params->format;
  }

  switch(format) {
    case CUBEB_SAMPLE_S16NE:
      return cubeb_resampler_create_internal<short>(stream,
                                                    input_params,
                                                    output_params,
                                                    target_rate,
                                                    callback,
                                                    user_ptr,
                                                    quality);
    case CUBEB_SAMPLE_FLOAT32NE:
      return cubeb_resampler_create_internal<float>(stream,
                                                    input_params,
                                                    output_params,
                                                    target_rate,
                                                    callback,
                                                    user_ptr,
                                                    quality);
    default:
      assert(false);
      return nullptr;
  }
}

long
cubeb_resampler_fill(cubeb_resampler * resampler,
                     void * input_buffer,
                     long * input_frames_count,
                     void * output_buffer,
                     long output_frames_needed)
{
  return resampler->fill(input_buffer, input_frames_count,
                         output_buffer, output_frames_needed);
}

void
cubeb_resampler_destroy(cubeb_resampler * resampler)
{
  delete resampler;
}

long
cubeb_resampler_latency(cubeb_resampler * resampler)
{
  return resampler->latency();
}