/*

 * Copyright © 2011,2012,2013  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

 */

#include "hb.hh"

#ifndef HB_NO_OT_SHAPE

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

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

#include "hb-ot-layout.hh"

/*

 * Myanmar shaper.

 */

static const hb_tag_t

myanmar_basic_features[] =

{

  /*

   * Basic features.

   * These features are applied in order, one at a time, after reordering,

   * constrained to the syllable.

   */

  HB_TAG('r','p','h','f'),

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

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

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

};

static const hb_tag_t

myanmar_other_features[] =

{

  /*

   * Other features.

   * These features are applied all at once, after clearing syllables.

   */

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

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

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

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

};

static inline void

set_myanmar_properties (hb_glyph_info_t &info)

{

  hb_codepoint_t u = info.codepoint;

  unsigned int type = hb_indic_get_categories (u);

  info.myanmar_category() = (myanmar_category_t) (type & 0xFFu);

}

static inline bool

is_one_of_myanmar (const hb_glyph_info_t &info, unsigned int flags)

{

  /* If it ligated, all bets are off. */

  if (_hb_glyph_info_ligated (&info)) return false;

  return !!(FLAG_UNSAFE (info.myanmar_category()) & flags);

}

/* Note:

 *

 * We treat Vowels and placeholders as if they were consonants.  This is safe because Vowels

 * cannot happen in a consonant syllable.  The plus side however is, we can call the

 * consonant syllable logic from the vowel syllable function and get it all right!

 *

 * Keep in sync with consonant_categories in the generator. */

#define CONSONANT_FLAGS_MYANMAR (FLAG (M_Cat(C)) | FLAG (M_Cat(CS)) | FLAG (M_Cat(Ra)) | /* FLAG (M_Cat(CM)) | */ FLAG (M_Cat(IV)) | FLAG (M_Cat(GB)) | FLAG (M_Cat(DOTTEDCIRCLE)))

static inline bool

is_consonant_myanmar (const hb_glyph_info_t &info)

{

  return is_one_of_myanmar (info, CONSONANT_FLAGS_MYANMAR);

}

static bool

setup_syllables_myanmar (const hb_ot_shape_plan_t *plan,

       hb_font_t *font,

       hb_buffer_t *buffer);

static bool

reorder_myanmar (const hb_ot_shape_plan_t *plan,

     hb_font_t *font,

     hb_buffer_t *buffer);

static void

collect_features_myanmar (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_myanmar);

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

  /* The Indic specs do not require ccmp, but we apply it here since if

   * there is a use of it, it's typically at the beginning. */

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

  map->add_gsub_pause (reorder_myanmar);

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

  {

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

    map->add_gsub_pause (nullptr);

  }

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

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

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

}

static void

setup_masks_myanmar (const hb_ot_shape_plan_t *plan HB_UNUSED,

         hb_buffer_t              *buffer,

         hb_font_t                *font HB_UNUSED)

{

  HB_BUFFER_ALLOCATE_VAR (buffer, myanmar_category);

  HB_BUFFER_ALLOCATE_VAR (buffer, myanmar_position);

  /* No masks, we just save information about characters. */

  unsigned int count = buffer->len;

  hb_glyph_info_t *info = buffer->info;

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

    set_myanmar_properties (info[i]);

}

static bool

setup_syllables_myanmar (const hb_ot_shape_plan_t *plan HB_UNUSED,

       hb_font_t *font HB_UNUSED,

       hb_buffer_t *buffer)

{

  HB_BUFFER_ALLOCATE_VAR (buffer, syllable);

  find_syllables_myanmar (buffer);

  foreach_syllable (buffer, start, end)

    buffer->unsafe_to_break (start, end);

  return false;

}

static int

compare_myanmar_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)

{

  int a = pa->myanmar_position();

  int b = pb->myanmar_position();

  return (int) a - (int) b;

}

/* Rules from:

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

static void

initial_reordering_consonant_syllable (hb_buffer_t *buffer,

               unsigned int start, unsigned int end)

{

  hb_glyph_info_t *info = buffer->info;

  unsigned int base = end;

  bool has_reph = false;

  {

    unsigned int limit = start;

    if (start + 3 <= end &&

  info[start  ].myanmar_category() == M_Cat(Ra) &&

  info[start+1].myanmar_category() == M_Cat(As) &&

  info[start+2].myanmar_category() == M_Cat(H))

    {

      limit += 3;

      base = start;

      has_reph = true;

    }

    {

      if (!has_reph)

  base = limit;

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

  if (is_consonant_myanmar (info[i]))

  {

    base = i;

    break;

  }

    }

  }

  /* Reorder! */

  {

    unsigned int i = start;

    for (; i < start + (has_reph ? 3 : 0); i++)

      info[i].myanmar_position() = POS_AFTER_MAIN;

    for (; i < base; i++)

      info[i].myanmar_position() = POS_PRE_C;

    if (i < end)

    {

      info[i].myanmar_position() = POS_BASE_C;

      i++;

    }

    myanmar_position_t pos = POS_AFTER_MAIN;

    /* The following loop may be ugly, but it implements all of

     * Myanmar reordering! */

    for (; i < end; i++)

    {

      if (info[i].myanmar_category() == M_Cat(MR)) /* Pre-base reordering */

      {

  info[i].myanmar_position() = POS_PRE_C;

  continue;

      }

      if (info[i].myanmar_category() == M_Cat(VPre)) /* Left matra */

      {

  info[i].myanmar_position() = POS_PRE_M;

  continue;

      }

      if (info[i].myanmar_category() == M_Cat(VS))

      {

  info[i].myanmar_position() = info[i - 1].myanmar_position();

  continue;

      }

      if (pos == POS_AFTER_MAIN && info[i].myanmar_category() == M_Cat(VBlw))

      {

  pos = POS_BELOW_C;

  info[i].myanmar_position() = pos;

  continue;

      }

      if (pos == POS_BELOW_C && info[i].myanmar_category() == M_Cat(A))

      {

  info[i].myanmar_position() = POS_BEFORE_SUB;

  continue;

      }

      if (pos == POS_BELOW_C && info[i].myanmar_category() == M_Cat(VBlw))

      {

  info[i].myanmar_position() = pos;

  continue;

      }

      if (pos == POS_BELOW_C && info[i].myanmar_category() != M_Cat(A))

      {

  pos = POS_AFTER_SUB;

  info[i].myanmar_position() = pos;

  continue;

      }

      info[i].myanmar_position() = pos;

    }

  }

  /* Sit tight, rock 'n roll! */

  buffer->sort (start, end, compare_myanmar_order);

  /* Flip left-matra sequence. */

  unsigned first_left_matra = end;

  unsigned last_left_matra = end;

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

  {

    if (info[i].myanmar_position() == POS_PRE_M)

    {

      if (first_left_matra == end)

  first_left_matra = i;

      last_left_matra = i;

    }

  }

  /* https://github.com/harfbuzz/harfbuzz/issues/3863 */

  if (first_left_matra < last_left_matra)

  {

    /* No need to merge clusters, done already? */

    buffer->reverse_range (first_left_matra, last_left_matra + 1);

    /* Reverse back VS, etc. */

    unsigned i = first_left_matra;

    for (unsigned j = i; j <= last_left_matra; j++)

      if (info[j].myanmar_category() == M_Cat(VPre))

      {

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

  i = j + 1;

      }

  }

}

static void

reorder_syllable_myanmar (const hb_ot_shape_plan_t *plan HB_UNUSED,

        hb_face_t *face HB_UNUSED,

        hb_buffer_t *buffer,

        unsigned int start, unsigned int end)

{

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

  switch (syllable_type) {

    case myanmar_broken_cluster: /* We already inserted dotted-circles, so just call the consonant_syllable. */

    case myanmar_consonant_syllable:

      initial_reordering_consonant_syllable  (buffer, start, end);

      break;

    case myanmar_non_myanmar_cluster:

      break;

  }

}

static bool

reorder_myanmar (const hb_ot_shape_plan_t *plan,

     hb_font_t *font,

     hb_buffer_t *buffer)

{

  bool ret = false;

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

  {

    if (hb_syllabic_insert_dotted_circles (font, buffer,

             myanmar_broken_cluster,

             M_Cat(DOTTEDCIRCLE)))

      ret = true;

    foreach_syllable (buffer, start, end)

      reorder_syllable_myanmar (plan, font->face, buffer, start, end);

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

  }

  HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_category);

  HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_position);

  return ret;

}

const hb_ot_shaper_t _hb_ot_shaper_myanmar =

{

  collect_features_myanmar,

  nullptr, /* override_features */

  nullptr, /* data_create */

  nullptr, /* data_destroy */

  nullptr, /* preprocess_text */

  nullptr, /* postprocess_glyphs */

  nullptr, /* decompose */

  nullptr, /* compose */

  setup_masks_myanmar,

  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 */

};

#ifndef HB_NO_OT_SHAPER_MYANMAR_ZAWGYI

/* Ugly Zawgyi encoding.

 * Disable all auto processing.

 * https://github.com/harfbuzz/harfbuzz/issues/1162 */

const hb_ot_shaper_t _hb_ot_shaper_myanmar_zawgyi =

{

  nullptr, /* collect_features */

  nullptr, /* override_features */

  nullptr, /* data_create */

  nullptr, /* data_destroy */

  nullptr, /* preprocess_text */

  nullptr, /* postprocess_glyphs */

  nullptr, /* decompose */

  nullptr, /* compose */

  nullptr, /* setup_masks */

  nullptr, /* reorder_marks */

  HB_TAG_NONE, /* gpos_tag */

  HB_OT_SHAPE_NORMALIZATION_MODE_NONE,

  HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,

  false, /* fallback_position */

};

#endif

#endif