// 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.

#include "lib/jxl/dec_patch_dictionary.h"

#include <jxl/memory_manager.h>

#include <algorithm>

#include <cstddef>

#include <cstdint>

#include <cstdlib>

#include <utility>

#include <vector>

#include "lib/jxl/base/printf_macros.h"

#include "lib/jxl/base/status.h"

#include "lib/jxl/blending.h"

#include "lib/jxl/common.h"  // kMaxNumReferenceFrames

#include "lib/jxl/dec_ans.h"

#include "lib/jxl/dec_bit_reader.h"

#include "lib/jxl/image.h"

#include "lib/jxl/image_bundle.h"

#include "lib/jxl/image_metadata.h"

#include "lib/jxl/pack_signed.h"

#include "lib/jxl/patch_dictionary_internal.h"

namespace jxl {

Status PatchDictionary::Decode(JxlMemoryManager* memory_manager, BitReader* br,

                               size_t xsize, size_t ysize,

                               size_t num_extra_channels,

                               bool* uses_extra_channels) {

  // The dictionary is reused across frames: blendings_ is indexed by position

  // index, so stale entries from a previous frame must not remain.

  positions_.clear();

  ref_positions_.clear();

  blendings_.clear();

  blendings_stride_ = num_extra_channels + 1;

  std::vector<uint8_t> context_map;

  ANSCode code;

  JXL_RETURN_IF_ERROR(DecodeHistograms(

      memory_manager, br, kNumPatchDictionaryContexts, &code, &context_map));

  JXL_ASSIGN_OR_RETURN(ANSSymbolReader decoder,

                       ANSSymbolReader::Create(&code, br));

  auto read_num = [&](size_t context) -> size_t {

    size_t r = decoder.ReadHybridUint(context, br, context_map);

    return r;

  };

  size_t num_ref_patch = read_num(kNumRefPatchContext);

  // Limit max memory usage of patches to about 66 bytes per pixel (assuming 8

  // bytes per size_t)

  const size_t num_pixels = xsize * ysize;

  const size_t max_ref_patches = 1024 + num_pixels / 4;

  const size_t max_patches = max_ref_patches * 4;

  const size_t max_blending_infos = max_patches * 4;

  if (num_ref_patch > max_ref_patches) {

    return JXL_FAILURE("Too many patches in dictionary");

  }

  size_t total_patches = 0;

  size_t next_size = 1;

  for (size_t id = 0; id < num_ref_patch; id++) {

    PatchReferencePosition ref_pos;

    ref_pos.ref = read_num(kReferenceFrameContext);

    if (ref_pos.ref >= kMaxNumReferenceFrames ||

        reference_frames_->at(ref_pos.ref).frame->xsize() == 0) {

      return JXL_FAILURE("Invalid reference frame ID");

    }

    if (!reference_frames_->at(ref_pos.ref).ib_is_in_xyb) {

      return JXL_FAILURE(

          "Patches cannot use frames saved post color transforms");

    }

    const ImageBundle& ib = *reference_frames_->at(ref_pos.ref).frame;

    ref_pos.x0 = read_num(kPatchReferencePositionContext);

    ref_pos.y0 = read_num(kPatchReferencePositionContext);

    ref_pos.xsize = read_num(kPatchSizeContext) + 1;

    ref_pos.ysize = read_num(kPatchSizeContext) + 1;

    if (ref_pos.x0 + ref_pos.xsize > ib.xsize()) {

      return JXL_FAILURE("Invalid position specified in reference frame");

    }

    if (ref_pos.y0 + ref_pos.ysize > ib.ysize()) {

      return JXL_FAILURE("Invalid position specified in reference frame");

    }

    size_t id_count = read_num(kPatchCountContext);

    if (id_count > max_patches) {

      return JXL_FAILURE("Too many patches in dictionary");

    }

    id_count++;

    total_patches += id_count;

    if (total_patches > max_patches) {

      return JXL_FAILURE("Too many patches in dictionary");

    }

    if (next_size < total_patches) {

      next_size *= 2;

      next_size = std::min<size_t>(next_size, max_patches);

    }

    if (next_size * blendings_stride_ > max_blending_infos) {

      return JXL_FAILURE("Too many patches in dictionary");

    }

    positions_.reserve(next_size);

    blendings_.reserve(next_size * blendings_stride_);

    bool choose_alpha = (num_extra_channels > 1);

    for (size_t i = 0; i < id_count; i++) {

      PatchPosition pos;

      pos.ref_pos_idx = ref_positions_.size();

      if (i == 0) {

        pos.x = read_num(kPatchPositionContext);

        pos.y = read_num(kPatchPositionContext);

      } else {

        ptrdiff_t deltax = UnpackSigned(read_num(kPatchOffsetContext));

        if (deltax < 0 && static_cast<size_t>(-deltax) > positions_.back().x) {

          return JXL_FAILURE("Invalid patch: negative x coordinate (%" PRIuS

                             " base x %" PRIdS " delta x)",

                             positions_.back().x, deltax);

        }

        pos.x = positions_.back().x + deltax;

        ptrdiff_t deltay = UnpackSigned(read_num(kPatchOffsetContext));

        if (deltay < 0 && static_cast<size_t>(-deltay) > positions_.back().y) {

          return JXL_FAILURE("Invalid patch: negative y coordinate (%" PRIuS

                             " base y %" PRIdS " delta y)",

                             positions_.back().y, deltay);

        }

        pos.y = positions_.back().y + deltay;

      }

      if (pos.x + ref_pos.xsize > xsize) {

        return JXL_FAILURE("Invalid patch x: at %" PRIuS " + %" PRIuS

                           " > %" PRIuS,

                           pos.x, ref_pos.xsize, xsize);

      }

      if (pos.y + ref_pos.ysize > ysize) {

        return JXL_FAILURE("Invalid patch y: at %" PRIuS " + %" PRIuS

                           " > %" PRIuS,

                           pos.y, ref_pos.ysize, ysize);

      }

      for (size_t j = 0; j < blendings_stride_; j++) {

        uint32_t blend_mode = read_num(kPatchBlendModeContext);

        if (blend_mode >= kNumPatchBlendModes) {

          return JXL_FAILURE("Invalid patch blend mode: %u", blend_mode);

        }

        PatchBlending info;

        info.mode = static_cast<PatchBlendMode>(blend_mode);

        if (UsesAlpha(info.mode)) {

          *uses_extra_channels = true;

        }

        if (info.mode != PatchBlendMode::kNone && j > 0) {

          *uses_extra_channels = true;

        }

        if (UsesAlpha(info.mode) && choose_alpha) {

          info.alpha_channel = read_num(kPatchAlphaChannelContext);

          if (info.alpha_channel >= num_extra_channels) {

            return JXL_FAILURE(

                "Invalid alpha channel for blending: %u out of %u\n",

                info.alpha_channel, static_cast<uint32_t>(num_extra_channels));

          }

        } else {

          info.alpha_channel = 0;

        }

        if (UsesClamp(info.mode)) {

          info.clamp = static_cast<bool>(read_num(kPatchClampContext));

        } else {

          info.clamp = false;

        }

        blendings_.push_back(info);

      }

      positions_.emplace_back(pos);

    }

    ref_positions_.emplace_back(ref_pos);

  }

  positions_.shrink_to_fit();

  if (!decoder.CheckANSFinalState()) {

    return JXL_FAILURE("ANS checksum failure.");

  }

  ComputePatchTree();

  return true;

}

int PatchDictionary::GetReferences() const {

  int result = 0;

  for (const auto& ref_pos : ref_positions_) {

    result |= (1 << static_cast<int>(ref_pos.ref));

  }

  return result;

}

namespace {

struct PatchInterval {

  size_t idx;

  size_t y0, y1;

};

}  // namespace

void PatchDictionary::ComputePatchTree() {

  patch_tree_.clear();

  num_patches_.clear();

  sorted_patches_y0_.clear();

  sorted_patches_y1_.clear();

  if (positions_.empty()) {

    return;

  }

  // Create a y-interval for each patch.

  std::vector<PatchInterval> intervals(positions_.size());

  for (size_t i = 0; i < positions_.size(); ++i) {

    const auto& pos = positions_[i];

    intervals[i].idx = i;

    intervals[i].y0 = pos.y;

    intervals[i].y1 = pos.y + ref_positions_[pos.ref_pos_idx].ysize;

  }

  auto sort_by_y0 = [&intervals](size_t start, size_t end) {

    std::sort(intervals.data() + start, intervals.data() + end,

              [](const PatchInterval& i0, const PatchInterval& i1) {

                return i0.y0 < i1.y0;

              });

  };

  auto sort_by_y1 = [&intervals](size_t start, size_t end) {

    std::sort(intervals.data() + start, intervals.data() + end,

              [](const PatchInterval& i0, const PatchInterval& i1) {

                return i0.y1 < i1.y1;

              });

  };

  // Count the number of patches for each row.

  sort_by_y1(0, intervals.size());

  num_patches_.resize(intervals.back().y1);

  for (auto iv : intervals) {

    for (size_t y = iv.y0; y < iv.y1; ++y) num_patches_[y]++;

  }

  PatchTreeNode root;

  root.start = 0;

  root.num = intervals.size();

  patch_tree_.push_back(root);

  size_t next = 0;

  while (next < patch_tree_.size()) {

    auto& node = patch_tree_[next];

    size_t start = node.start;

    size_t end = node.start + node.num;

    // Choose the y_center for this node to be the median of interval starts.

    sort_by_y0(start, end);

    size_t middle_idx = start + node.num / 2;

    node.y_center = intervals[middle_idx].y0;

    // Divide the intervals in [start, end) into three groups:

    //   * those completely to the right of y_center: [right_start, end)

    //   * those overlapping y_center: [left_end, right_start)

    //   * those completely to the left of y_center: [start, left_end)

    size_t right_start = middle_idx;

    while (right_start < end && intervals[right_start].y0 == node.y_center) {

      ++right_start;

    }

    sort_by_y1(start, right_start);

    size_t left_end = right_start;

    while (left_end > start && intervals[left_end - 1].y1 > node.y_center) {

      --left_end;

    }

    // Fill in sorted_patches_y0_ and sorted_patches_y1_ for the current node.

    node.num = right_start - left_end;

    node.start = sorted_patches_y0_.size();

    for (ptrdiff_t i = static_cast<ptrdiff_t>(right_start) - 1;

         i >= static_cast<ptrdiff_t>(left_end); --i) {

      sorted_patches_y1_.emplace_back(intervals[i].y1, intervals[i].idx);

    }

    sort_by_y0(left_end, right_start);

    for (size_t i = left_end; i < right_start; ++i) {

      sorted_patches_y0_.emplace_back(intervals[i].y0, intervals[i].idx);

    }

    // Create the left and right nodes (if not empty).

    node.left_child = node.right_child = -1;

    if (left_end > start) {

      PatchTreeNode left;

      left.start = start;

      left.num = left_end - left.start;

      patch_tree_[next].left_child = patch_tree_.size();

      patch_tree_.push_back(left);

    }

    if (right_start < end) {

      PatchTreeNode right;

      right.start = right_start;

      right.num = end - right.start;

      patch_tree_[next].right_child = patch_tree_.size();

      patch_tree_.push_back(right);

    }

    ++next;

  }

}

std::vector<size_t> PatchDictionary::GetPatchesForRow(size_t y) const {

  std::vector<size_t> result;

  if (y < num_patches_.size() && num_patches_[y] > 0) {

    result.reserve(num_patches_[y]);

    for (ptrdiff_t tree_idx = 0; tree_idx != -1;) {

      JXL_DASSERT(tree_idx < static_cast<ptrdiff_t>(patch_tree_.size()));

      const auto& node = patch_tree_[tree_idx];

      if (y <= node.y_center) {

        for (size_t i = 0; i < node.num; ++i) {

          const auto& p = sorted_patches_y0_[node.start + i];

          if (y < p.first) break;

          result.push_back(p.second);

        }

        tree_idx = y < node.y_center ? node.left_child : -1;

      } else {

        for (size_t i = 0; i < node.num; ++i) {

          const auto& p = sorted_patches_y1_[node.start + i];

          if (y >= p.first) break;

          result.push_back(p.second);

        }

        tree_idx = node.right_child;

      }

    }

    // Ensure that he relative order of patches that affect the same pixels is

    // preserved. This is important for patches that have a blend mode

    // different from kAdd.

    std::sort(result.begin(), result.end());

  }

  return result;

}

// Adds patches to a segment of `xsize` pixels, starting at `inout`, assumed

// to be located at position (x0, y) in the frame.

Status PatchDictionary::AddOneRow(

    float* const* inout, size_t y, size_t x0, size_t xsize,

    const std::vector<ExtraChannelInfo>& extra_channel_info) const {

  size_t num_ec = extra_channel_info.size();

  JXL_ENSURE(num_ec + 1 <= blendings_stride_);

  std::vector<const float*> fg_ptrs(3 + num_ec);

  for (size_t pos_idx : GetPatchesForRow(y)) {

    const size_t blending_idx = pos_idx * blendings_stride_;

    const PatchPosition& pos = positions_[pos_idx];

    const PatchReferencePosition& ref_pos = ref_positions_[pos.ref_pos_idx];

    size_t by = pos.y;

    size_t bx = pos.x;

    size_t patch_xsize = ref_pos.xsize;

    JXL_ENSURE(y >= by);

    JXL_ENSURE(y < by + ref_pos.ysize);

    size_t iy = y - by;

    size_t ref = ref_pos.ref;

    if (bx >= x0 + xsize) continue;

    if (bx + patch_xsize < x0) continue;

    size_t patch_x0 = std::max(bx, x0);

    size_t patch_x1 = std::min(bx + patch_xsize, x0 + xsize);

    for (size_t c = 0; c < 3; c++) {

      fg_ptrs[c] = reference_frames_->at(ref).frame->color()->ConstPlaneRow(

                       c, ref_pos.y0 + iy) +

                   ref_pos.x0 + x0 - bx;

    }

    for (size_t i = 0; i < num_ec; i++) {

      fg_ptrs[3 + i] =

          reference_frames_->at(ref).frame->extra_channels()[i].ConstRow(

              ref_pos.y0 + iy) +

          ref_pos.x0 + x0 - bx;

    }

    JXL_RETURN_IF_ERROR(PerformBlending(

        memory_manager_, inout, fg_ptrs.data(), inout, patch_x0 - x0,

        patch_x1 - patch_x0, blendings_[blending_idx],

        blendings_.data() + blending_idx + 1, extra_channel_info));

  }

  return true;

}

}  // namespace jxl