/*

 * Copyright © 2015  Mozilla Foundation.

 * Copyright © 2015  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.

 *

 * Mozilla Author(s): Jonathan Kew

 * Google Author(s): Behdad Esfahbod

 */

#include "hb-ot-shape-complex-use.hh"

#include "hb-ot-shape-complex-arabic.hh"

#include "hb-ot-shape-complex-vowel-constraints.hh"

/* buffer var allocations */

#define use_category() complex_var_u8_0()

/*

 * Universal Shaping Engine.

 * https://docs.microsoft.com/en-us/typography/script-development/use

 */

static const hb_tag_t

basic_features[] =

{

  /*

   * Basic features.

   * These features are applied all at once, before reordering.

   */

  HB_TAG('r','k','r','f'),

  HB_TAG('a','b','v','f'),

  HB_TAG('b','l','w','f'),

  HB_TAG('h','a','l','f'),

  HB_TAG('p','s','t','f'),

  HB_TAG('v','a','t','u'),

  HB_TAG('c','j','c','t'),

};

static const hb_tag_t

arabic_features[] =

{

  HB_TAG('i','s','o','l'),

  HB_TAG('i','n','i','t'),

  HB_TAG('m','e','d','i'),

  HB_TAG('f','i','n','a'),

  /* The spec doesn't specify these but we apply anyway, since our Arabic shaper

   * does.  These are only used in Syriac spec. */

  HB_TAG('m','e','d','2'),

  HB_TAG('f','i','n','2'),

  HB_TAG('f','i','n','3'),

};

/* Same order as arabic_features.  Don't need Syriac stuff.*/

enum joining_form_t {

  ISOL,

  INIT,

  MEDI,

  FINA,

  _NONE

};

static const hb_tag_t

other_features[] =

{

  /*

   * Other features.

   * These features are applied all at once, after reordering and

   * clearing syllables.

   */

  HB_TAG('a','b','v','s'),

  HB_TAG('b','l','w','s'),

  HB_TAG('h','a','l','n'),

  HB_TAG('p','r','e','s'),

  HB_TAG('p','s','t','s'),

};

static const hb_tag_t

positioning_features[] =

{

  /*

   * Positioning features.

   * We don't care about the types.

   */

  HB_TAG('d','i','s','t'),

  HB_TAG('a','b','v','m'),

  HB_TAG('b','l','w','m'),

};

static void

setup_syllables (const hb_ot_shape_plan_t *plan,

                 hb_font_t *font,

                 hb_buffer_t *buffer);

static void

clear_substitution_flags (const hb_ot_shape_plan_t *plan,

                          hb_font_t *font,

                          hb_buffer_t *buffer);

static void

record_rphf (const hb_ot_shape_plan_t *plan,

             hb_font_t *font,

             hb_buffer_t *buffer);

static void

record_pref (const hb_ot_shape_plan_t *plan,

             hb_font_t *font,

             hb_buffer_t *buffer);

static void

reorder (const hb_ot_shape_plan_t *plan,

         hb_font_t *font,

         hb_buffer_t *buffer);

static void

clear_syllables (const hb_ot_shape_plan_t *plan,

                 hb_font_t *font,

                 hb_buffer_t *buffer);

static void

collect_features_use (hb_ot_shape_planner_t *plan)

{

  hb_ot_map_builder_t *map = &plan->map;

  /* Do this before any lookups have been applied. */

  map->add_gsub_pause (setup_syllables);

  /* "Default glyph pre-processing group" */

  map->enable_feature (HB_TAG('l','o','c','l'));

  map->enable_feature (HB_TAG('c','c','m','p'));

  map->enable_feature (HB_TAG('n','u','k','t'));

  map->enable_feature (HB_TAG('a','k','h','n'), F_MANUAL_ZWJ);

  /* "Reordering group" */

  map->add_gsub_pause (clear_substitution_flags);

  map->add_feature (HB_TAG('r','p','h','f'), F_MANUAL_ZWJ);

  map->add_gsub_pause (record_rphf);

  map->add_gsub_pause (clear_substitution_flags);

  map->enable_feature (HB_TAG('p','r','e','f'), F_MANUAL_ZWJ);

  map->add_gsub_pause (record_pref);

  /* "Orthographic unit shaping group" */

  for (unsigned int i = 0; i < ARRAY_LENGTH (basic_features); i++)

    map->enable_feature (basic_features[i], F_MANUAL_ZWJ);

  map->add_gsub_pause (reorder);

  map->add_gsub_pause (clear_syllables);

  /* "Topographical features" */

  for (unsigned int i = 0; i < ARRAY_LENGTH (arabic_features); i++)

    map->add_feature (arabic_features[i]);

  map->add_gsub_pause (nullptr);

  /* "Standard typographic presentation" */

  for (unsigned int i = 0; i < ARRAY_LENGTH (other_features); i++)

    map->enable_feature (other_features[i], F_MANUAL_ZWJ);

  /* "Positional feature application" */

  for (unsigned int i = 0; i < ARRAY_LENGTH (positioning_features); i++)

    map->enable_feature (positioning_features[i]);

}

struct use_shape_plan_t

{

  hb_mask_t rphf_mask;

  arabic_shape_plan_t *arabic_plan;

};

static bool

has_arabic_joining (hb_script_t script)

{

  /* List of scripts that have data in arabic-table. */

  switch ((int) script)

  {

    /* Unicode-1.1 additions */

    case HB_SCRIPT_ARABIC:

    /* Unicode-3.0 additions */

    case HB_SCRIPT_MONGOLIAN:

    case HB_SCRIPT_SYRIAC:

    /* Unicode-5.0 additions */

    case HB_SCRIPT_NKO:

    case HB_SCRIPT_PHAGS_PA:

    /* Unicode-6.0 additions */

    case HB_SCRIPT_MANDAIC:

    /* Unicode-7.0 additions */

    case HB_SCRIPT_MANICHAEAN:

    case HB_SCRIPT_PSALTER_PAHLAVI:

    /* Unicode-9.0 additions */

    case HB_SCRIPT_ADLAM:

      return true;

    default:

      return false;

  }

}

static void *

data_create_use (const hb_ot_shape_plan_t *plan)

{

  use_shape_plan_t *use_plan = (use_shape_plan_t *) calloc (1, sizeof (use_shape_plan_t));

  if (unlikely (!use_plan))

    return nullptr;

  use_plan->rphf_mask = plan->map.get_1_mask (HB_TAG('r','p','h','f'));

  if (has_arabic_joining (plan->props.script))

  {

    use_plan->arabic_plan = (arabic_shape_plan_t *) data_create_arabic (plan);

    if (unlikely (!use_plan->arabic_plan))

    {

      free (use_plan);

      return nullptr;

    }

  }

  return use_plan;

}

static void

data_destroy_use (void *data)

{

  use_shape_plan_t *use_plan = (use_shape_plan_t *) data;

  if (use_plan->arabic_plan)

    data_destroy_arabic (use_plan->arabic_plan);

  free (data);

}

enum syllable_type_t {

  independent_cluster,

  virama_terminated_cluster,

  standard_cluster,

  number_joiner_terminated_cluster,

  numeral_cluster,

  symbol_cluster,

  broken_cluster,

  non_cluster,

};

#include "hb-ot-shape-complex-use-machine.hh"

static void

setup_masks_use (const hb_ot_shape_plan_t *plan,

                 hb_buffer_t              *buffer,

                 hb_font_t                *font HB_UNUSED)

{

  const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;

  /* Do this before allocating use_category(). */

  if (use_plan->arabic_plan)

  {

    setup_masks_arabic_plan (use_plan->arabic_plan, buffer, plan->props.script);

  }

  HB_BUFFER_ALLOCATE_VAR (buffer, use_category);

  /* We cannot setup masks here.  We save information about characters

   * and setup masks later on in a pause-callback. */

  unsigned int count = buffer->len;

  hb_glyph_info_t *info = buffer->info;

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

    info[i].use_category() = hb_use_get_category (info[i].codepoint);

}

static void

setup_rphf_mask (const hb_ot_shape_plan_t *plan,

                 hb_buffer_t *buffer)

{

  const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;

  hb_mask_t mask = use_plan->rphf_mask;

  if (!mask) return;

  hb_glyph_info_t *info = buffer->info;

  foreach_syllable (buffer, start, end)

  {

    unsigned int limit = info[start].use_category() == USE_R ? 1 : MIN (3u, end - start);

    for (unsigned int i = start; i < start + limit; i++)

      info[i].mask |= mask;

  }

}

static void

setup_topographical_masks (const hb_ot_shape_plan_t *plan,

                           hb_buffer_t *buffer)

{

  const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;

  if (use_plan->arabic_plan)

    return;

  static_assert ((INIT < 4 && ISOL < 4 && MEDI < 4 && FINA < 4), "");

  hb_mask_t masks[4], all_masks = 0;

  for (unsigned int i = 0; i < 4; i++)

  {

    masks[i] = plan->map.get_1_mask (arabic_features[i]);

    if (masks[i] == plan->map.get_global_mask ())

      masks[i] = 0;

    all_masks |= masks[i];

  }

  if (!all_masks)

    return;

  hb_mask_t other_masks = ~all_masks;

  unsigned int last_start = 0;

  joining_form_t last_form = _NONE;

  hb_glyph_info_t *info = buffer->info;

  foreach_syllable (buffer, start, end)

  {

    syllable_type_t syllable_type = (syllable_type_t) (info[start].syllable() & 0x0F);

    switch (syllable_type)

    {

      case independent_cluster:

      case symbol_cluster:

      case non_cluster:

        /* These don't join.  Nothing to do. */

        last_form = _NONE;

        break;

      case virama_terminated_cluster:

      case standard_cluster:

      case number_joiner_terminated_cluster:

      case numeral_cluster:

      case broken_cluster:

        bool join = last_form == FINA || last_form == ISOL;

        if (join)

        {

          /* Fixup previous syllable's form. */

          last_form = last_form == FINA ? MEDI : INIT;

          for (unsigned int i = last_start; i < start; i++)

            info[i].mask = (info[i].mask & other_masks) | masks[last_form];

        }

        /* Form for this syllable. */

        last_form = join ? FINA : ISOL;

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

          info[i].mask = (info[i].mask & other_masks) | masks[last_form];

        break;

    }

    last_start = start;

  }

}

static void

setup_syllables (const hb_ot_shape_plan_t *plan,

                 hb_font_t *font HB_UNUSED,

                 hb_buffer_t *buffer)

{

  find_syllables (buffer);

  foreach_syllable (buffer, start, end)

    buffer->unsafe_to_break (start, end);

  setup_rphf_mask (plan, buffer);

  setup_topographical_masks (plan, buffer);

}

static void

clear_substitution_flags (const hb_ot_shape_plan_t *plan HB_UNUSED,

                          hb_font_t *font HB_UNUSED,

                          hb_buffer_t *buffer)

{

  hb_glyph_info_t *info = buffer->info;

  unsigned int count = buffer->len;

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

    _hb_glyph_info_clear_substituted (&info[i]);

}

static void

record_rphf (const hb_ot_shape_plan_t *plan,

             hb_font_t *font HB_UNUSED,

             hb_buffer_t *buffer)

{

  const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;

  hb_mask_t mask = use_plan->rphf_mask;

  if (!mask) return;

  hb_glyph_info_t *info = buffer->info;

  foreach_syllable (buffer, start, end)

  {

    /* Mark a substituted repha as USE_R. */

    for (unsigned int i = start; i < end && (info[i].mask & mask); i++)

      if (_hb_glyph_info_substituted (&info[i]))

      {

        info[i].use_category() = USE_R;

        break;

      }

  }

}

static void

record_pref (const hb_ot_shape_plan_t *plan HB_UNUSED,

             hb_font_t *font HB_UNUSED,

             hb_buffer_t *buffer)

{

  hb_glyph_info_t *info = buffer->info;

  foreach_syllable (buffer, start, end)

  {

    /* Mark a substituted pref as VPre, as they behave the same way. */

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

      if (_hb_glyph_info_substituted (&info[i]))

      {

        info[i].use_category() = USE_VPre;

        break;

      }

  }

}

static inline bool

is_halant (const hb_glyph_info_t &info)

{

  return (info.use_category() == USE_H || info.use_category() == USE_HVM) &&

         !_hb_glyph_info_ligated (&info);

}

static void

reorder_syllable (hb_buffer_t *buffer, unsigned int start, unsigned int end)

{

  syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F);

  /* Only a few syllable types need reordering. */

  if (unlikely (!(FLAG_UNSAFE (syllable_type) &

                  (FLAG (virama_terminated_cluster) |

                   FLAG (standard_cluster) |

                   FLAG (broken_cluster) |

                   0))))

    return;

  hb_glyph_info_t *info = buffer->info;

#define POST_BASE_FLAGS64 (FLAG64 (USE_FM) | \

                           FLAG64 (USE_FAbv) | \

                           FLAG64 (USE_FBlw) | \

                           FLAG64 (USE_FPst) | \

                           FLAG64 (USE_MAbv) | \

                           FLAG64 (USE_MBlw) | \

                           FLAG64 (USE_MPst) | \

                           FLAG64 (USE_MPre) | \

                           FLAG64 (USE_VAbv) | \

                           FLAG64 (USE_VBlw) | \

                           FLAG64 (USE_VPst) | \

                           FLAG64 (USE_VPre) | \

                           FLAG64 (USE_VMAbv) | \

                           FLAG64 (USE_VMBlw) | \

                           FLAG64 (USE_VMPst) | \

                           FLAG64 (USE_VMPre))

  /* Move things forward. */

  if (info[start].use_category() == USE_R && end - start > 1)

  {

    /* Got a repha.  Reorder it towards the end, but before the first post-base

     * glyph. */

    for (unsigned int i = start + 1; i < end; i++)

    {

      bool is_post_base_glyph = (FLAG64_UNSAFE (info[i].use_category()) & POST_BASE_FLAGS64) ||

                                is_halant (info[i]);

      if (is_post_base_glyph || i == end - 1)

      {

        /* If we hit a post-base glyph, move before it; otherwise move to the

         * end. Shift things in between backward. */

        if (is_post_base_glyph)

          i--;

        buffer->merge_clusters (start, i + 1);

        hb_glyph_info_t t = info[start];

        memmove (&info[start], &info[start + 1], (i - start) * sizeof (info[0]));

        info[i] = t;

        break;

      }

    }

  }

  /* Move things back. */

  unsigned int j = start;

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

  {

    uint32_t flag = FLAG_UNSAFE (info[i].use_category());

    if (is_halant (info[i]))

    {

      /* If we hit a halant, move after it; otherwise move to the beginning, and

       * shift things in between forward. */

      j = i + 1;

    }

    else if (((flag) & (FLAG (USE_VPre) | FLAG (USE_VMPre))) &&

             /* Only move the first component of a MultipleSubst. */

             0 == _hb_glyph_info_get_lig_comp (&info[i]) &&

             j < i)

    {

      buffer->merge_clusters (j, i + 1);

      hb_glyph_info_t t = info[i];

      memmove (&info[j + 1], &info[j], (i - j) * sizeof (info[0]));

      info[j] = t;

    }