// Copyright (c) the JPEG XL 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.

#ifndef LIB_JXL_ENC_AC_STRATEGY_H_
#define LIB_JXL_ENC_AC_STRATEGY_H_

#include <cstddef>
#include <cstdint>
#include <hwy/aligned_allocator.h>

#include "lib/jxl/ac_strategy.h"
#include "lib/jxl/base/compiler_specific.h"
#include "lib/jxl/base/status.h"
#include "lib/jxl/chroma_from_luma.h"
#include "lib/jxl/enc_cache.h"
#include "lib/jxl/enc_params.h"
#include "lib/jxl/frame_dimensions.h"
#include "lib/jxl/image.h"
#include "lib/jxl/quant_weights.h"

// `FindBestAcStrategy` uses heuristics to choose which AC strategy should be
// used in each block, as well as the initial quantization field.

namespace jxl {

struct AuxOut;

// AC strategy selection: utility struct.

struct ACSConfig {
  const DequantMatrices* JXL_RESTRICT dequant;
  const float* JXL_RESTRICT quant_field_row;
  size_t quant_field_stride;
  const float* JXL_RESTRICT masking_field_row;
  size_t masking_field_stride;
  const float* JXL_RESTRICT masking1x1_field_row;
  size_t masking1x1_field_stride;
  const float* JXL_RESTRICT src_rows[3];
  size_t src_stride;
  float info_loss_multiplier;
  float cost_delta;
  float zeros_mul;
  const float& Pixel(size_t c, size_t x, size_t y) const {
    return src_rows[c][y * src_stride + x];
  }
  float Masking(size_t bx, size_t by) const {
    JXL_DASSERT(masking_field_row[by * masking_field_stride + bx] > 0);
    return masking_field_row[by * masking_field_stride + bx];
  }
  const float* MaskingPtr1x1(size_t bx, size_t by) const {
    JXL_DASSERT(masking1x1_field_row[by * masking1x1_field_stride + bx] > 0);
    return &masking1x1_field_row[by * masking1x1_field_stride + bx];
  }
  float Quant(size_t bx, size_t by) const {
    JXL_DASSERT(quant_field_row[by * quant_field_stride + bx] > 0);
    return quant_field_row[by * quant_field_stride + bx];
  }
};

struct AcStrategyHeuristics {
  explicit AcStrategyHeuristics(const CompressParams& cparams)
      : cparams(cparams), mem_per_thread(0), qmem_per_thread(0) {}
  void Init(const Image3F& src, const Rect& rect_in, const ImageF& quant_field,
            const ImageF& mask, const ImageF& mask1x1,
            DequantMatrices* matrices);
  void PrepareForThreads(std::size_t num_threads);
  void ProcessRect(const Rect& rect, const ColorCorrelationMap& cmap,
                   AcStrategyImage* ac_strategy, size_t thread);
  Status Finalize(const FrameDimensions& frame_dim,
                  const AcStrategyImage& ac_strategy, AuxOut* aux_out);
  const CompressParams& cparams;
  ACSConfig config = {};
  size_t mem_per_thread;
  hwy::AlignedFreeUniquePtr<float[]> mem;
  size_t qmem_per_thread;
  hwy::AlignedFreeUniquePtr<uint32_t[]> qmem;
};

}  // namespace jxl

#endif  // LIB_JXL_ENC_AC_STRATEGY_H_