/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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#ifndef ReverbConvolverStage_h
#define ReverbConvolverStage_h

#include "platform/audio/AudioArray.h"
#include "platform/audio/FFTFrame.h"
#include "wtf/Allocator.h"
#include "wtf/Noncopyable.h"
#include <memory>

namespace blink {

class ReverbAccumulationBuffer;
class ReverbConvolver;
class FFTConvolver;
class DirectConvolver;

// A ReverbConvolverStage represents the convolution associated with a
// sub-section of a large impulse response.  It incorporates a delay line to
// account for the offset of the sub-section within the larger impulse
// response.
class PLATFORM_EXPORT ReverbConvolverStage {
  USING_FAST_MALLOC(ReverbConvolverStage);
  WTF_MAKE_NONCOPYABLE(ReverbConvolverStage);

 public:
  // renderPhase is useful to know so that we can manipulate the pre versus post
  // delay so that stages will perform their heavy work (FFT processing) on
  // different slices to balance the load in a real-time thread.
  ReverbConvolverStage(const float* impulseResponse,
                       size_t responseLength,
                       size_t reverbTotalLatency,
                       size_t stageOffset,
                       size_t stageLength,
                       size_t fftSize,
                       size_t renderPhase,
                       size_t renderSliceSize,
                       ReverbAccumulationBuffer*,
                       bool directMode = false);

  // WARNING: framesToProcess must be such that it evenly divides the delay
  // buffer size (stage_offset).
  void process(const float* source, size_t framesToProcess);

  void processInBackground(ReverbConvolver* convolver, size_t framesToProcess);

  void reset();

  // Useful for background processing
  int inputReadIndex() const { return m_inputReadIndex; }

 private:
  std::unique_ptr<FFTFrame> m_fftKernel;
  std::unique_ptr<FFTConvolver> m_fftConvolver;

  AudioFloatArray m_preDelayBuffer;

  ReverbAccumulationBuffer* m_accumulationBuffer;
  int m_accumulationReadIndex;
  int m_inputReadIndex;

  size_t m_preDelayLength;
  size_t m_postDelayLength;
  size_t m_preReadWriteIndex;
  size_t m_framesProcessed;

  AudioFloatArray m_temporaryBuffer;

  bool m_directMode;
  std::unique_ptr<AudioFloatArray> m_directKernel;
  std::unique_ptr<DirectConvolver> m_directConvolver;
};

}  // namespace blink

#endif  // ReverbConvolverStage_h