/*
libspecbleach - A spectral processing library

Copyright 2022 Luciano Dato <lucianodato@gmail.com>

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "noise_estimator.h"
#include "../configurations.h"
#include "../utils/spectral_trailing_buffer.h"
#include "../utils/spectral_utils.h"
#include <stdlib.h>
#include <string.h>

struct NoiseEstimator {
  uint32_t fft_size;
  uint32_t real_spectrum_size;
  SpectralTrailingBuffer* median_buffer;

  NoiseProfile* noise_profile;
};

NoiseEstimator* noise_estimation_initialize(const uint32_t fft_size,
                                            NoiseProfile* noise_profile) {
  NoiseEstimator* self = (NoiseEstimator*)calloc(1U, sizeof(NoiseEstimator));

  if (!self) {
    return NULL;
  }

  self->fft_size = fft_size;
  self->real_spectrum_size = (self->fft_size / 2U) + 1U;

  self->noise_profile = noise_profile;
  self->median_buffer = spectral_trailing_buffer_initialize(
      self->real_spectrum_size, NUMBER_OF_MEDIAN_SPECTRUM);

  if (!self->median_buffer) {
    noise_estimation_free(self);
    return NULL;
  }

  return self;
}

void noise_estimation_free(NoiseEstimator* self) {
  if (!self) {
    return;
  }

  // Don't free noise profile used as reference here

  spectral_trailing_buffer_free(self->median_buffer);

  free(self);
}

bool noise_estimation_run(NoiseEstimator* self,
                          const NoiseEstimatorType noise_estimator_type,
                          float* signal_spectrum) {
  if (!self || !signal_spectrum) {
    return false;
  }

  float* noise_profile =
      get_noise_profile(self->noise_profile, noise_estimator_type);

  switch (noise_estimator_type) {
    case ROLLING_MEAN:
      get_rolling_mean_spectrum(noise_profile, signal_spectrum,
                                get_noise_profile_blocks_averaged(
                                    self->noise_profile, noise_estimator_type),
                                self->real_spectrum_size);
      increment_blocks_averaged(self->noise_profile, noise_estimator_type);
      break;
    case MEDIAN:
      spectral_trailing_buffer_push_back(self->median_buffer, signal_spectrum);
      bool is_valid_median = get_rolling_median_spectrum(
          noise_profile, get_trailing_spectral_buffer(self->median_buffer),
          get_spectrum_buffer_size(self->median_buffer),
          get_spectrum_size(self->median_buffer));
      if (is_valid_median) {
        set_noise_profile_available(self->noise_profile, noise_estimator_type);
      }
      break;
    case MAX:
      (void)max_spectrum(noise_profile, signal_spectrum,
                         self->real_spectrum_size);
      set_noise_profile_available(self->noise_profile, noise_estimator_type);
      break;

    default:
      break;
  }

  return true;
}
