/*
 *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#ifndef MODULES_AUDIO_PROCESSING_NS_NOISE_SUPPRESSOR_H_
#define MODULES_AUDIO_PROCESSING_NS_NOISE_SUPPRESSOR_H_

#include <memory>
#include <vector>

#include "array_view.h"
#include "audio_buffer.h"
#include "noise_estimator.h"
#include "ns_common.h"
#include "ns_config.h"
#include "ns_fft.h"
#include "speech_probability_estimator.h"
#include "wiener_filter.h"

namespace webrtc {

// Class for suppressing noise in a signal.
    class NoiseSuppressor {
    public:
        NoiseSuppressor(const NsConfig &config,
                        size_t sample_rate_hz,
                        size_t num_channels);

        NoiseSuppressor(const NoiseSuppressor &) = delete;

        NoiseSuppressor &operator=(const NoiseSuppressor &) = delete;

        // Analyses the signal (typically applied before the AEC to avoid analyzing
        // any comfort noise signal).
        void Analyze(const AudioBuffer &audio);

        // Applies noise suppression.
        void Process(AudioBuffer *audio);

    private:
        const size_t num_bands_;
        const size_t num_channels_;
        const SuppressionParams suppression_params_;
        int32_t num_analyzed_frames_ = -1;
        NrFft fft_;

        struct ChannelState {
            ChannelState(const SuppressionParams &suppression_params, size_t num_bands);

            SpeechProbabilityEstimator speech_probability_estimator;
            WienerFilter wiener_filter;
            NoiseEstimator noise_estimator;
            std::array<float, kFftSizeBy2Plus1> prev_analysis_signal_spectrum{};
            std::array<float, kFftSize - kNsFrameSize> analyze_analysis_memory{};
            std::array<float, kOverlapSize> process_analysis_memory{};
            std::array<float, kOverlapSize> process_synthesis_memory{};
            std::vector<std::array<float, kOverlapSize>> process_delay_memory;
        };

        struct FilterBankState {
            std::array<float, kFftSize> real;
            std::array<float, kFftSize> imag;
            std::array<float, kFftSize> extended_frame;
        };

        std::vector<FilterBankState> filter_bank_states_heap_;
        std::vector<float> upper_band_gains_heap_;
        std::vector<float> energies_before_filtering_heap_;
        std::vector<float> gain_adjustments_heap_;
        std::vector<std::unique_ptr<ChannelState>> channels_;

        // Aggregates the Wiener filters into a single filter to use.
        void AggregateWienerFilters(
                rtc::ArrayView<float, kFftSizeBy2Plus1> filter) const;
    };

}  // namespace webrtc

#endif  // MODULES_AUDIO_PROCESSING_NS_NOISE_SUPPRESSOR_H_