/*

 * 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.hh"

#ifndef HB_NO_OT_SHAPE

#include "hb-ot-shaper-use-machine.hh"

#include "hb-ot-shaper-use-table.hh"

#include "hb-ot-shaper-arabic.hh"

#include "hb-ot-shaper-arabic-joining-list.hh"

#include "hb-ot-shaper-vowel-constraints.hh"

/*

 * Universal Shaping Engine.

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

 */

static const hb_tag_t

use_basic_features[] =

{

  /*

   * Basic features.

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

   * to the syllable.

   */

  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

use_topographical_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'),

};

/* Same order as use_topographical_features. */

enum joining_form_t {

  JOINING_FORM_ISOL,

  JOINING_FORM_INIT,

  JOINING_FORM_MEDI,

  JOINING_FORM_FINA,

  _JOINING_FORM_NONE

};

static const hb_tag_t

use_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 bool

setup_syllables_use (const hb_ot_shape_plan_t *plan,

         hb_font_t *font,

         hb_buffer_t *buffer);

static bool

record_rphf_use (const hb_ot_shape_plan_t *plan,

     hb_font_t *font,

     hb_buffer_t *buffer);

static bool

record_pref_use (const hb_ot_shape_plan_t *plan,

     hb_font_t *font,

     hb_buffer_t *buffer);

static bool

reorder_use (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_use);

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

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

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

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

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

  /* "Reordering group" */

  map->add_gsub_pause (_hb_clear_substitution_flags);

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

  map->add_gsub_pause (record_rphf_use);

  map->add_gsub_pause (_hb_clear_substitution_flags);

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

  map->add_gsub_pause (record_pref_use);

  /* "Orthographic unit shaping group" */

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

    map->enable_feature (use_basic_features[i], F_MANUAL_ZWJ | F_PER_SYLLABLE);

  map->add_gsub_pause (reorder_use);

  map->add_gsub_pause (hb_syllabic_clear_var); // Don't need syllables anymore, use stop to free buffer var

  /* "Topographical features" */

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

    map->add_feature (use_topographical_features[i]);

  map->add_gsub_pause (nullptr);

  /* "Standard typographic presentation" */

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

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

}

struct use_shape_plan_t

{

  hb_mask_t rphf_mask;

  arabic_shape_plan_t *arabic_plan;

};

static void *

data_create_use (const hb_ot_shape_plan_t *plan)

{

  use_shape_plan_t *use_plan = (use_shape_plan_t *) hb_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))

    {

      hb_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);

  hb_free (data);

}

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 : hb_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 ((JOINING_FORM_INIT < 4 && JOINING_FORM_ISOL < 4 && JOINING_FORM_MEDI < 4 && JOINING_FORM_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 (use_topographical_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 = _JOINING_FORM_NONE;

  hb_glyph_info_t *info = buffer->info;

  foreach_syllable (buffer, start, end)

  {

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

    switch (syllable_type)

    {

      case use_hieroglyph_cluster:

      case use_non_cluster:

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

  last_form = _JOINING_FORM_NONE;

  break;

      case use_virama_terminated_cluster:

      case use_sakot_terminated_cluster:

      case use_standard_cluster:

      case use_number_joiner_terminated_cluster:

      case use_numeral_cluster:

      case use_symbol_cluster:

      case use_broken_cluster:

  bool join = last_form == JOINING_FORM_FINA || last_form == JOINING_FORM_ISOL;

  if (join)

  {

    /* Fixup previous syllable's form. */

    last_form = last_form == JOINING_FORM_FINA ? JOINING_FORM_MEDI : JOINING_FORM_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 ? JOINING_FORM_FINA : JOINING_FORM_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 bool

setup_syllables_use (const hb_ot_shape_plan_t *plan,

         hb_font_t *font HB_UNUSED,

         hb_buffer_t *buffer)

{

  HB_BUFFER_ALLOCATE_VAR (buffer, syllable);

  find_syllables_use (buffer);

  foreach_syllable (buffer, start, end)

    buffer->unsafe_to_break (start, end);

  setup_rphf_mask (plan, buffer);

  setup_topographical_masks (plan, buffer);

  return false;

}

static bool

record_rphf_use (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 false;

  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;

      }

  }

  return false;

}

static bool

record_pref_use (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;

      }

  }

  return false;

}

static inline bool

is_halant_use (const hb_glyph_info_t &info)

{

  return (info.use_category() == USE(H) || info.use_category() == USE(HVM) || info.use_category() == USE(IS)) &&

   !_hb_glyph_info_ligated (&info);

}

static void

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

{

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

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

  if (unlikely (!(FLAG_UNSAFE (syllable_type) &

      (FLAG (use_virama_terminated_cluster) |

       FLAG (use_sakot_terminated_cluster) |

       FLAG (use_standard_cluster) |

       FLAG (use_symbol_cluster) |

       FLAG (use_broken_cluster) |

       0))))

    return;

  hb_glyph_info_t *info = buffer->info;

#define POST_BASE_FLAGS64 (FLAG64 (USE(FAbv)) | \

         FLAG64 (USE(FBlw)) | \

         FLAG64 (USE(FPst)) | \

         FLAG64 (USE(FMAbv)) | \

         FLAG64 (USE(FMBlw)) | \

         FLAG64 (USE(FMPst)) | \

         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_use (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_use (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;

    }

  }

}

static bool

reorder_use (const hb_ot_shape_plan_t *plan,

       hb_font_t *font,

       hb_buffer_t *buffer)

{

  bool ret = false;

  if (buffer->message (font, "start reordering USE"))

  {

    if (hb_syllabic_insert_dotted_circles (font, buffer,

             use_broken_cluster,

             USE(B),

             USE(R)))

      ret = true;

    foreach_syllable (buffer, start, end)

      reorder_syllable_use (buffer, start, end);

    (void) buffer->message (font, "end reordering USE");

  }

  HB_BUFFER_DEALLOCATE_VAR (buffer, use_category);

  return ret;

}

static void

preprocess_text_use (const hb_ot_shape_plan_t *plan,

         hb_buffer_t              *buffer,

         hb_font_t                *font)

{

  _hb_preprocess_text_vowel_constraints (plan, buffer, font);

}

static bool

compose_use (const hb_ot_shape_normalize_context_t *c,

       hb_codepoint_t  a,

       hb_codepoint_t  b,

       hb_codepoint_t *ab)

{

  /* Avoid recomposing split matras. */

  if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a)))

    return false;

  return (bool)c->unicode->compose (a, b, ab);

}

const hb_ot_shaper_t _hb_ot_shaper_use =

{

  collect_features_use,

  nullptr, /* override_features */

  data_create_use,

  data_destroy_use,

  preprocess_text_use,

  nullptr, /* postprocess_glyphs */

  nullptr, /* decompose */

  compose_use,

  setup_masks_use,

  nullptr, /* reorder_marks */

  HB_TAG_NONE, /* gpos_tag */

  HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,

  HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,

  false, /* fallback_position */

};

#endif