/*

 * Copyright © 2017  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): Behdad Esfahbod

 */

#ifndef HB_OT_VAR_AVAR_TABLE_HH

#define HB_OT_VAR_AVAR_TABLE_HH

#include "hb-open-type.hh"

#include "hb-ot-var-common.hh"

/*

 * avar -- Axis Variations

 * https://docs.microsoft.com/en-us/typography/opentype/spec/avar

 */

#define HB_OT_TAG_avar HB_TAG('a','v','a','r')

namespace OT {

/* "Spec": https://github.com/be-fonts/boring-expansion-spec/issues/14 */

struct avarV2Tail

{

  friend struct avar;

  bool sanitize (hb_sanitize_context_t *c,

     const void *base) const

  {

    TRACE_SANITIZE (this);

    return_trace (varIdxMap.sanitize (c, base) &&

      varStore.sanitize (c, base));

  }

  protected:

  Offset32To<DeltaSetIndexMap>  varIdxMap;  /* Offset from the beginning of 'avar' table. */

  Offset32To<ItemVariationStore>  varStore; /* Offset from the beginning of 'avar' table. */

  public:

  DEFINE_SIZE_STATIC (8);

};

struct AxisValueMap

{

  bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (c->check_struct (this));

  }

  void set_mapping (float from_coord, float to_coord)

  {

    coords[0].set_float (from_coord);

    coords[1].set_float (to_coord);

  }

  bool is_outside_axis_range (const Triple& axis_range) const

  {

    double from_coord = (double) coords[0].to_float ();

    return !axis_range.contains (from_coord);

  }

  bool must_include () const

  {

    float from_coord = coords[0].to_float ();

    float to_coord = coords[1].to_float ();

    return (from_coord == -1.f && to_coord == -1.f) ||

           (from_coord == 0.f && to_coord == 0.f) ||

           (from_coord == 1.f && to_coord == 1.f);

  }

  void instantiate (const Triple& axis_range,

                    const Triple& unmapped_range,

                    const TripleDistances& triple_distances)

  {

    float from_coord = coords[0].to_float ();

    float to_coord = coords[1].to_float ();

    from_coord = renormalizeValue ((double) from_coord, unmapped_range, triple_distances);

    to_coord = renormalizeValue ((double) to_coord, axis_range, triple_distances);

    coords[0].set_float (from_coord);

    coords[1].set_float (to_coord);

  }

  HB_INTERNAL static int cmp (const void *pa, const void *pb)

  {

    const AxisValueMap *a = (const AxisValueMap *) pa;

    const AxisValueMap *b = (const AxisValueMap *) pb;

    int a_from = a->coords[0].to_int ();

    int b_from = b->coords[0].to_int ();

    if (a_from != b_from)

      return a_from - b_from;

    /* this should never be reached. according to the spec, all of the axis

     * value map records for a given axis must have different fromCoord values

     * */

    int a_to = a->coords[1].to_int ();

    int b_to = b->coords[1].to_int ();

    return a_to - b_to;

  }

  bool serialize (hb_serialize_context_t *c) const

  {

    TRACE_SERIALIZE (this);

    return_trace (c->embed (this));

  }

  public:

  F2DOT14 coords[2];

//   F2DOT14  fromCoord;  /* A normalized coordinate value obtained using

//         * default normalization. */

//   F2DOT14  toCoord;  /* The modified, normalized coordinate value. */

  public:

  DEFINE_SIZE_STATIC (4);

};

struct SegmentMaps : Array16Of<AxisValueMap>

{

  float map_float (float value, unsigned int from_offset = 0, unsigned int to_offset = 1) const

  {

#define fromCoord coords[from_offset].to_float ()

#define toCoord coords[to_offset].to_float ()

    const auto *map = arrayZ;

    /* The following special-cases are not part of OpenType, which requires

     * that at least -1, 0, and +1 must be mapped. But we include these as

     * part of a better error recovery scheme. */

    if (len < 2)

    {

      if (!len)

  return value;

      else /* len == 1*/

  return value - map[0].fromCoord + map[0].toCoord;

    }

    // At least two mappings now.

    /* CoreText is wild...

     * PingFangUI avar needs all this special-casing...

     * So we implement an extended version of the spec here,

     * which is more robust and more likely to be compatible with

     * the wild. */

    unsigned start = 0;

    unsigned end = len;

    if (map[start].fromCoord == -1 && map[start].toCoord == -1 and map[start+1].fromCoord == -1)

      start++;

    if (map[end-1].fromCoord == +1 && map[end-1].toCoord == +1 and map[end-2].fromCoord == +1)

      end--;

    /* Look for exact match first, and do lots of special-casing. */

    unsigned i;

    for (i = start; i < end; i++)

      if (value == map[i].fromCoord)

  break;

    if (i < end)

    {

      // There's at least one exact match. See if there are more.

      unsigned j = i;

      for (; j + 1 < end; j++)

  if (value != map[j + 1].fromCoord)

    break;

      // [i,j] inclusive are all exact matches:

      // If there's only one, return it. This is the only spec-compliant case.

      if (i == j)

  return map[i].toCoord;

      // If there's exactly three, return the middle one.

      if (i + 2 == j)

  return map[i + 1].toCoord;

      // Ignore the middle ones. Return the one mapping closer to 0.

      if (value < 0) return map[j].toCoord;

      if (value > 0) return map[i].toCoord;

      // Mapping 0? CoreText seems confused. It seems to prefer 0 here...

      // So we'll just return the smallest one. lol

      return fabsf (map[i].toCoord) < fabsf (map[j].toCoord) ? map[i].toCoord : map[j].toCoord;

      // Mapping 0? Return one not mapping to 0.

      if (map[i].toCoord == 0)

  return map[j].toCoord;

      else

  return map[i].toCoord;

    }

    /* There's at least two and we're not an exact match. Prepare to lerp. */

    // Find the segment we're in.

    for (i = start; i < end; i++)

      if (value < map[i].fromCoord)

  break;

    if (i == 0)

    {

      // Value before all segments; Shift.

      return value - map[0].fromCoord + map[0].toCoord;

    }

    if (i == end)

    {

      // Value after all segments; Shift.

      return value - map[end - 1].fromCoord + map[end - 1].toCoord;

    }

    // Actually interpolate.

    auto &before = map[i-1];

    auto &after = map[i];

    float denom = after.fromCoord - before.fromCoord; // Can't be zero by now.

    return before.toCoord + ((after.toCoord - before.toCoord) * (value - before.fromCoord)) / denom;

#undef toCoord

#undef fromCoord

  }

  float unmap_float (float value) const { return map_float (value, 1, 0); }

  // TODO Kill this.

  Triple unmap_axis_range (const Triple& axis_range) const

  {

    float unmapped_min = unmap_float (axis_range.minimum);

    float unmapped_middle = unmap_float (axis_range.middle);

    float unmapped_max = unmap_float (axis_range.maximum);

    return Triple{(double) unmapped_min, (double) unmapped_middle, (double) unmapped_max};

  }

  bool subset (hb_subset_context_t *c, hb_tag_t axis_tag) const

  {

    TRACE_SUBSET (this);

    /* This function cannot work on avar2 table (and currently doesn't).

     * We should instead keep the design coords in the shape plan and use

     * those. unmap_axis_range needs to be killed. */

    /* avar mapped normalized axis range*/

    Triple *axis_range;

    if (!c->plan->axes_location.has (axis_tag, &axis_range))

      return c->serializer->embed (*this);

    TripleDistances *axis_triple_distances;

    if (!c->plan->axes_triple_distances.has (axis_tag, &axis_triple_distances))

      return_trace (false);

    auto *out = c->serializer->start_embed (this);

    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);

    Triple unmapped_range = unmap_axis_range (*axis_range);

    /* create a vector of retained mappings and sort */

    hb_vector_t<AxisValueMap> value_mappings;

    for (const auto& _ : as_array ())

    {

      if (_.is_outside_axis_range (unmapped_range))

        continue;

      AxisValueMap mapping;

      mapping = _;

      mapping.instantiate (*axis_range, unmapped_range, *axis_triple_distances);

      /* (-1, -1), (0, 0), (1, 1) mappings will be added later, so avoid

       * duplicates here */

      if (mapping.must_include ())

        continue;

      value_mappings.push (mapping);

    }

    AxisValueMap m;

    m.set_mapping (-1.f, -1.f);

    value_mappings.push (m);

    m.set_mapping (0.f, 0.f);

    value_mappings.push (m);

    m.set_mapping (1.f, 1.f);

    value_mappings.push (m);

    value_mappings.qsort ();

    for (const auto& _ : value_mappings)

    {

      if (!_.serialize (c->serializer))

        return_trace (false);

    }

    return_trace (c->serializer->check_assign (out->len, value_mappings.length, HB_SERIALIZE_ERROR_INT_OVERFLOW));

  }

  public:

  DEFINE_SIZE_ARRAY (2, *this);

};

struct avar

{

  static constexpr hb_tag_t tableTag = HB_OT_TAG_avar;

  bool has_data () const { return version.to_int (); }

  const SegmentMaps* get_segment_maps () const

  { return &firstAxisSegmentMaps; }

  unsigned get_axis_count () const

  { return axisCount; }

  bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    if (!(version.sanitize (c) &&

    hb_barrier () &&

    (version.major == 1

#ifndef HB_NO_AVAR2

     || version.major == 2

#endif

     ) &&

    c->check_struct (this)))

      return_trace (false);

    const SegmentMaps *map = &firstAxisSegmentMaps;

    unsigned int count = axisCount;

    for (unsigned int i = 0; i < count; i++)

    {

      if (unlikely (!map->sanitize (c)))

  return_trace (false);

      map = &StructAfter<SegmentMaps> (*map);

    }

#ifndef HB_NO_AVAR2

    if (version.major < 2)

      return_trace (true);

    hb_barrier ();

    const auto &v2 = * (const avarV2Tail *) map;

    if (unlikely (!v2.sanitize (c, this)))

      return_trace (false);

#endif

    return_trace (true);

  }

  void map_coords_16_16 (int *coords, unsigned int coords_length) const

  {

    unsigned int count = hb_min (coords_length, axisCount);

    const SegmentMaps *map = &firstAxisSegmentMaps;

    for (unsigned int i = 0; i < count; i++)

    {

      coords[i] = roundf (map->map_float (coords[i] / 65536.f) * 65536.f);

      map = &StructAfter<SegmentMaps> (*map);

    }

#ifndef HB_NO_AVAR2

    if (version.major < 2)

      return;

    hb_barrier ();

    for (; count < axisCount; count++)

      map = &StructAfter<SegmentMaps> (*map);

    const auto &v2 = * (const avarV2Tail *) map;

    const auto &varidx_map = this+v2.varIdxMap;

    const auto &var_store = this+v2.varStore;

    auto *var_store_cache = var_store.create_cache ();

    hb_vector_t<int> out;

    out.alloc (coords_length);

    for (unsigned i = 0; i < coords_length; i++)

    {

      int v = coords[i];

      uint32_t varidx = varidx_map.map (i);

      float delta = var_store.get_delta (varidx, coords, coords_length, var_store_cache);

      v += roundf (delta * 4); // 2.14 -> 16.16

      v = hb_clamp (v, -(1<<16), +(1<<16));

      out.push (v);

    }

    for (unsigned i = 0; i < coords_length; i++)

      coords[i] = out[i];

    OT::ItemVariationStore::destroy_cache (var_store_cache);

#endif

  }

  bool subset (hb_subset_context_t *c) const

  {

    TRACE_SUBSET (this);

    unsigned retained_axis_count = c->plan->axes_index_map.get_population ();

    if (!retained_axis_count) //all axes are pinned/dropped

      return_trace (false);

    avar *out = c->serializer->allocate_min<avar> ();

    if (unlikely (!out)) return_trace (false);

    out->version.major = 1;

    out->version.minor = 0;

    if (!c->serializer->check_assign (out->axisCount, retained_axis_count, HB_SERIALIZE_ERROR_INT_OVERFLOW))

      return_trace (false);

    const hb_map_t& axes_index_map = c->plan->axes_index_map;

    const SegmentMaps *map = &firstAxisSegmentMaps;

    unsigned count = axisCount;

    for (unsigned int i = 0; i < count; i++)

    {

      if (axes_index_map.has (i))

      {

        hb_tag_t *axis_tag;

        if (!c->plan->axes_old_index_tag_map.has (i, &axis_tag))

          return_trace (false);

        if (!map->subset (c, *axis_tag))

          return_trace (false);

      }

      map = &StructAfter<SegmentMaps> (*map);

    }

    return_trace (true);

  }

  protected:

  FixedVersion<>version;  /* Version of the avar table

         * initially set to 0x00010000u */

  HBUINT16  reserved; /* This field is permanently reserved. Set to 0. */

  HBUINT16  axisCount;  /* The number of variation axes in the font. This

         * must be the same number as axisCount in the

         * 'fvar' table. */

  SegmentMaps firstAxisSegmentMaps;

  public:

  DEFINE_SIZE_MIN (8);

};

} /* namespace OT */

#endif /* HB_OT_VAR_AVAR_TABLE_HH */