/*

 * Copyright © 2022  Google, Inc.

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 *

 * Google Author(s): Garret Rieger

 */

#ifndef GRAPH_MARKBASEPOS_GRAPH_HH

#define GRAPH_MARKBASEPOS_GRAPH_HH

#include "split-helpers.hh"

#include "coverage-graph.hh"

#include "../OT/Layout/GPOS/MarkBasePos.hh"

#include "../OT/Layout/GPOS/PosLookupSubTable.hh"

namespace graph {

struct AnchorMatrix : public OT::Layout::GPOS_impl::AnchorMatrix

{

  bool sanitize (graph_t::vertex_t& vertex, unsigned class_count) const

  {

    int64_t vertex_len = vertex.obj.tail - vertex.obj.head;

    if (vertex_len < AnchorMatrix::min_size) return false;

    hb_barrier ();

    return vertex_len >= AnchorMatrix::min_size +

        OT::Offset16::static_size * class_count * this->rows;

  }

  bool shrink (gsubgpos_graph_context_t& c,

               unsigned this_index,

               unsigned old_class_count,

               unsigned new_class_count)

  {

    if (new_class_count >= old_class_count) return false;

    auto& o = c.graph.vertices_[this_index].obj;

    unsigned base_count = rows;

    o.tail = o.head +

             AnchorMatrix::min_size +

             OT::Offset16::static_size * base_count * new_class_count;

    // Reposition links into the new indexing scheme.

    for (auto& link : o.real_links.writer ())

    {

      unsigned index = (link.position - 2) / 2;

      unsigned base = index / old_class_count;

      unsigned klass = index % old_class_count;

      if (klass >= new_class_count)

        // should have already been removed

        return false;

      unsigned new_index = base * new_class_count + klass;

      link.position = (char*) &(this->matrixZ[new_index]) - (char*) this;

    }

    return true;

  }

  unsigned clone (gsubgpos_graph_context_t& c,

                  unsigned this_index,

                  unsigned start,

                  unsigned end,

                  unsigned class_count)

  {

    unsigned base_count = rows;

    unsigned new_class_count = end - start;

    unsigned size = AnchorMatrix::min_size +

                    OT::Offset16::static_size * new_class_count * rows;

    unsigned prime_id = c.create_node (size);

    if (prime_id == (unsigned) -1) return -1;

    AnchorMatrix* prime = (AnchorMatrix*) c.graph.object (prime_id).head;

    prime->rows = base_count;

    auto& o = c.graph.vertices_[this_index].obj;

    int num_links = o.real_links.length;

    for (int i = 0; i < num_links; i++)

    {

      const auto& link = o.real_links[i];

      unsigned old_index = (link.position - 2) / OT::Offset16::static_size;

      unsigned klass = old_index % class_count;

      if (klass < start || klass >= end) continue;

      unsigned base = old_index / class_count;

      unsigned new_klass = klass - start;

      unsigned new_index = base * new_class_count + new_klass;

      unsigned child_idx = link.objidx;

      c.graph.add_link (&(prime->matrixZ[new_index]),

                        prime_id,

                        child_idx);

      auto& child = c.graph.vertices_[child_idx];

      child.remove_parent (this_index);

      o.real_links.remove_unordered (i);

      num_links--;

      i--;

    }

    return prime_id;

  }

};

struct MarkArray : public OT::Layout::GPOS_impl::MarkArray

{

  bool sanitize (graph_t::vertex_t& vertex) const

  {

    int64_t vertex_len = vertex.obj.tail - vertex.obj.head;

    unsigned min_size = MarkArray::min_size;

    if (vertex_len < min_size) return false;

    hb_barrier ();

    return vertex_len >= get_size ();

  }

  bool shrink (gsubgpos_graph_context_t& c,

               const hb_hashmap_t<unsigned, unsigned>& mark_array_links,

               unsigned this_index,

               unsigned new_class_count)

  {

    auto& o = c.graph.vertices_[this_index].obj;

    for (const auto& link : o.real_links)

      c.graph.vertices_[link.objidx].remove_parent (this_index);

    o.real_links.reset ();

    unsigned new_index = 0;

    for (const auto& record : this->iter ())

    {

      unsigned klass = record.klass;

      if (klass >= new_class_count) continue;

      (*this)[new_index].klass = klass;

      unsigned position = (char*) &record.markAnchor - (char*) this;

      unsigned* objidx;

      if (!mark_array_links.has (position, &objidx))

      {

        new_index++;

        continue;

      }

      c.graph.add_link (&(*this)[new_index].markAnchor, this_index, *objidx);

      new_index++;

    }

    this->len = new_index;

    o.tail = o.head + MarkArray::min_size +

             OT::Layout::GPOS_impl::MarkRecord::static_size * new_index;

    return true;

  }

  unsigned clone (gsubgpos_graph_context_t& c,

                  unsigned this_index,

                  const hb_hashmap_t<unsigned, unsigned>& pos_to_index,

                  hb_set_t& marks,

                  unsigned start_class)

  {

    unsigned size = MarkArray::min_size +

                    OT::Layout::GPOS_impl::MarkRecord::static_size *

                    marks.get_population ();

    unsigned prime_id = c.create_node (size);

    if (prime_id == (unsigned) -1) return -1;

    MarkArray* prime = (MarkArray*) c.graph.object (prime_id).head;

    prime->len = marks.get_population ();

    unsigned i = 0;

    for (hb_codepoint_t mark : marks)

    {

      (*prime)[i].klass = (*this)[mark].klass - start_class;

      unsigned offset_pos = (char*) &((*this)[mark].markAnchor) - (char*) this;

      unsigned* anchor_index;

      if (pos_to_index.has (offset_pos, &anchor_index))

        c.graph.move_child (this_index,

                            &((*this)[mark].markAnchor),

                            prime_id,

                            &((*prime)[i].markAnchor));

      i++;

    }

    return prime_id;

  }

};

struct MarkBasePosFormat1 : public OT::Layout::GPOS_impl::MarkBasePosFormat1_2<SmallTypes>

{

  bool sanitize (graph_t::vertex_t& vertex) const

  {

    int64_t vertex_len = vertex.obj.tail - vertex.obj.head;

    return vertex_len >= MarkBasePosFormat1::static_size;

  }

  hb_vector_t<unsigned> split_subtables (gsubgpos_graph_context_t& c,

                                         unsigned parent_index,

                                         unsigned this_index)

  {

    hb_set_t visited;

    const unsigned base_coverage_id = c.graph.index_for_offset (this_index, &baseCoverage);

    const unsigned base_size =

        OT::Layout::GPOS_impl::MarkBasePosFormat1_2<SmallTypes>::min_size +

        MarkArray::min_size +

        AnchorMatrix::min_size +

        c.graph.vertices_[base_coverage_id].table_size ();

    hb_vector_t<class_info_t> class_to_info = get_class_info (c, this_index);

    unsigned class_count = classCount;

    auto base_array = c.graph.as_table<AnchorMatrix> (this_index,

                                                      &baseArray,

                                                      class_count);

    if (!base_array) return hb_vector_t<unsigned> ();

    unsigned base_count = base_array.table->rows;

    unsigned partial_coverage_size = 4;

    unsigned accumulated = base_size;

    hb_vector_t<unsigned> split_points;

    for (unsigned klass = 0; klass < class_count; klass++)

    {

      class_info_t& info = class_to_info[klass];

      partial_coverage_size += OT::HBUINT16::static_size * info.marks.get_population ();

      unsigned accumulated_delta =

          OT::Layout::GPOS_impl::MarkRecord::static_size * info.marks.get_population () +

          OT::Offset16::static_size * base_count;

      for (unsigned objidx : info.child_indices)

        accumulated_delta += c.graph.find_subgraph_size (objidx, visited);

      accumulated += accumulated_delta;

      unsigned total = accumulated + partial_coverage_size;

      if (total >= (1 << 16))

      {

        split_points.push (klass);

        accumulated = base_size + accumulated_delta;

        partial_coverage_size = 4 + OT::HBUINT16::static_size * info.marks.get_population ();

        visited.clear (); // node sharing isn't allowed between splits.

      }

    }

    const unsigned mark_array_id = c.graph.index_for_offset (this_index, &markArray);

    split_context_t split_context {

      c,

      this,

      c.graph.duplicate_if_shared (parent_index, this_index),

      std::move (class_to_info),

      c.graph.vertices_[mark_array_id].position_to_index_map (),

    };

    return actuate_subtable_split<split_context_t> (split_context, split_points);

  }

 private:

  struct class_info_t {

    hb_set_t marks;

    hb_vector_t<unsigned> child_indices;

  };

  struct split_context_t {

    gsubgpos_graph_context_t& c;

    MarkBasePosFormat1* thiz;

    unsigned this_index;

    hb_vector_t<class_info_t> class_to_info;

    hb_hashmap_t<unsigned, unsigned> mark_array_links;

    hb_set_t marks_for (unsigned start, unsigned end)

    {

      hb_set_t marks;

      for (unsigned klass = start; klass < end; klass++)

      {

        + class_to_info[klass].marks.iter ()

        | hb_sink (marks)

        ;

      }

      return marks;

    }

    unsigned original_count ()

    {

      return thiz->classCount;

    }

    unsigned clone_range (unsigned start, unsigned end)

    {

      return thiz->clone_range (*this, this->this_index, start, end);

    }

    bool shrink (unsigned count)

    {

      return thiz->shrink (*this, this->this_index, count);

    }

  };

  hb_vector_t<class_info_t> get_class_info (gsubgpos_graph_context_t& c,

                                            unsigned this_index)

  {

    hb_vector_t<class_info_t> class_to_info;

    unsigned class_count = classCount;

    if (!class_count) return class_to_info;

    if (!class_to_info.resize (class_count))

      return hb_vector_t<class_info_t>();

    auto mark_array = c.graph.as_table<MarkArray> (this_index, &markArray);

    if (!mark_array) return hb_vector_t<class_info_t> ();

    unsigned mark_count = mark_array.table->len;

    for (unsigned mark = 0; mark < mark_count; mark++)

    {

      unsigned klass = (*mark_array.table)[mark].get_class ();

      if (klass >= class_count) continue;

      class_to_info[klass].marks.add (mark);

    }

    for (const auto& link : mark_array.vertex->obj.real_links)

    {

      unsigned mark = (link.position - 2) /

                     OT::Layout::GPOS_impl::MarkRecord::static_size;

      unsigned klass = (*mark_array.table)[mark].get_class ();

      if (klass >= class_count) continue;

      class_to_info[klass].child_indices.push (link.objidx);

    }

    unsigned base_array_id =

        c.graph.index_for_offset (this_index, &baseArray);

    auto& base_array_v = c.graph.vertices_[base_array_id];

    for (const auto& link : base_array_v.obj.real_links)

    {

      unsigned index = (link.position - 2) / OT::Offset16::static_size;

      unsigned klass = index % class_count;

      class_to_info[klass].child_indices.push (link.objidx);

    }

    return class_to_info;

  }

  bool shrink (split_context_t& sc,

               unsigned this_index,

               unsigned count)

  {

    DEBUG_MSG (SUBSET_REPACK, nullptr,

               "  Shrinking MarkBasePosFormat1 (%u) to [0, %u).",

               this_index,

               count);

    unsigned old_count = classCount;

    if (count >= old_count)

      return true;

    classCount = count;

    auto mark_coverage = sc.c.graph.as_mutable_table<Coverage> (this_index,

                                                                &markCoverage);

    if (!mark_coverage) return false;

    hb_set_t marks = sc.marks_for (0, count);

    auto new_coverage =

        + hb_enumerate (mark_coverage.table->iter ())

        | hb_filter (marks, hb_first)

        | hb_map_retains_sorting (hb_second)

        ;

    if (!Coverage::make_coverage (sc.c, + new_coverage,

                                  mark_coverage.index,

                                  4 + 2 * marks.get_population ()))

      return false;

    auto base_array = sc.c.graph.as_mutable_table<AnchorMatrix> (this_index,

                                                                 &baseArray,

                                                                 old_count);

    if (!base_array || !base_array.table->shrink (sc.c,

                                                  base_array.index,

                                                  old_count,

                                                  count))

      return false;

    auto mark_array = sc.c.graph.as_mutable_table<MarkArray> (this_index,

                                                              &markArray);

    if (!mark_array || !mark_array.table->shrink (sc.c,

                                                  sc.mark_array_links,

                                                  mark_array.index,

                                                  count))

      return false;

    return true;

  }

  // Create a new MarkBasePos that has all of the data for classes from [start, end).

  unsigned clone_range (split_context_t& sc,

                        unsigned this_index,

                        unsigned start, unsigned end) const

  {

    DEBUG_MSG (SUBSET_REPACK, nullptr,

               "  Cloning MarkBasePosFormat1 (%u) range [%u, %u).", this_index, start, end);

    graph_t& graph = sc.c.graph;

    unsigned prime_size = OT::Layout::GPOS_impl::MarkBasePosFormat1_2<SmallTypes>::static_size;

    unsigned prime_id = sc.c.create_node (prime_size);

    if (prime_id == (unsigned) -1) return -1;

    MarkBasePosFormat1* prime = (MarkBasePosFormat1*) graph.object (prime_id).head;

    prime->format = this->format;

    unsigned new_class_count = end - start;

    prime->classCount = new_class_count;

    unsigned base_coverage_id =

        graph.index_for_offset (sc.this_index, &baseCoverage);

    graph.add_link (&(prime->baseCoverage), prime_id, base_coverage_id);

    graph.duplicate (prime_id, base_coverage_id);

    auto mark_coverage = sc.c.graph.as_table<Coverage> (this_index,

                                                        &markCoverage);

    if (!mark_coverage) return false;

    hb_set_t marks = sc.marks_for (start, end);

    auto new_coverage =

        + hb_enumerate (mark_coverage.table->iter ())

        | hb_filter (marks, hb_first)

        | hb_map_retains_sorting (hb_second)

        ;

    if (!Coverage::add_coverage (sc.c,

                                 prime_id,

                                 2,

                                 + new_coverage,

                                 marks.get_population () * 2 + 4))

      return -1;

    auto mark_array =

        graph.as_table <MarkArray> (sc.this_index, &markArray);

    if (!mark_array) return -1;

    unsigned new_mark_array =

        mark_array.table->clone (sc.c,

                                 mark_array.index,

                                 sc.mark_array_links,

                                 marks,

                                 start);

    graph.add_link (&(prime->markArray), prime_id, new_mark_array);

    unsigned class_count = classCount;

    auto base_array =

        graph.as_table<AnchorMatrix> (sc.this_index, &baseArray, class_count);

    if (!base_array) return -1;

    unsigned new_base_array =

        base_array.table->clone (sc.c,

                                 base_array.index,

                                 start, end, this->classCount);

    graph.add_link (&(prime->baseArray), prime_id, new_base_array);

    return prime_id;

  }

};

struct MarkBasePos : public OT::Layout::GPOS_impl::MarkBasePos

{

  hb_vector_t<unsigned> split_subtables (gsubgpos_graph_context_t& c,

                                         unsigned parent_index,

                                         unsigned this_index)

  {

    switch (u.format) {

    case 1:

      return ((MarkBasePosFormat1*)(&u.format1))->split_subtables (c, parent_index, this_index);

#ifndef HB_NO_BEYOND_64K

    case 2: HB_FALLTHROUGH;

      // Don't split 24bit MarkBasePos's.

#endif

    default:

      return hb_vector_t<unsigned> ();

    }

  }

  bool sanitize (graph_t::vertex_t& vertex) const

  {

    int64_t vertex_len = vertex.obj.tail - vertex.obj.head;

    if (vertex_len < u.format.get_size ()) return false;

    hb_barrier ();

    switch (u.format) {

    case 1:

      return ((MarkBasePosFormat1*)(&u.format1))->sanitize (vertex);

#ifndef HB_NO_BEYOND_64K

    case 2: HB_FALLTHROUGH;

#endif

    default:

      // We don't handle format 3 and 4 here.

      return false;

    }

  }

};

}

#endif  // GRAPH_MARKBASEPOS_GRAPH_HH