/*

 * 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-ot-shape-complex-myanmar-private.hh"

/*

 * Myanmar shaper.

 */

static const hb_tag_t

basic_features[] =

{

  /*

   * Basic features.

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

   */

  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

other_features[] =

{

  /*

   * Other features.

   * These features are applied all at once, after final_reordering.

   */

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

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

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

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

  /* Positioning features, though we don't care about the types. */

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

  /* Pre-release version of Windows 8 Myanmar font had abvm,blwm

   * features.  The released Windows 8 version of the font (as well

   * as the released spec) used 'mark' instead.  The Windows 8

   * shaper however didn't apply 'mark' but did apply 'mkmk'.

   * Perhaps it applied abvm/blwm.  This was fixed in a Windows 8

   * update, so now it applies mark/mkmk.  We are guessing that

   * it still applies abvm/blwm too.

   */

  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

initial_reordering (const hb_ot_shape_plan_t *plan,

                    hb_font_t *font,

                    hb_buffer_t *buffer);

static void

final_reordering (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);

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

  /* 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->add_global_bool_feature (HB_TAG('c','c','m','p'));

  map->add_gsub_pause (initial_reordering);

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

  {

    map->add_feature (basic_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);

    map->add_gsub_pause (nullptr);

  }

  map->add_gsub_pause (final_reordering);

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

    map->add_feature (other_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);

}

static void

override_features_myanmar (hb_ot_shape_planner_t *plan)

{

  plan->map.add_feature (HB_TAG('l','i','g','a'), 0, F_GLOBAL);

}

enum syllable_type_t {

  consonant_syllable,

  punctuation_cluster,

  broken_cluster,

  non_myanmar_cluster,

};

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

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);

  /* 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++)

    set_myanmar_properties (info[i]);

}

static void

setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,

                 hb_font_t *font HB_UNUSED,

                 hb_buffer_t *buffer)

{

  find_syllables (buffer);

  foreach_syllable (buffer, start, end)

    buffer->unsafe_to_break (start, end);

}

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 a < b ? -1 : a == b ? 0 : +1;

}

/* Rules from:

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() == OT_Ra &&

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

        info[start+2].myanmar_category() == OT_H)

    {

      limit += 3;

      base = start;

      has_reph = true;

    }

    {

      if (!has_reph)

        base = limit;

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

        if (is_consonant (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++;

    }

    indic_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() == OT_MR) /* Pre-base reordering */

      {

        info[i].myanmar_position() = POS_PRE_C;

        continue;

      }

      if (info[i].myanmar_position() < POS_BASE_C) /* Left matra */

      {

        continue;

      }

      if (info[i].myanmar_category() == OT_VS)

      {

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

        continue;

      }

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

      {

        pos = POS_BELOW_C;

        info[i].myanmar_position() = pos;

        continue;

      }

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

      {

        info[i].myanmar_position() = POS_BEFORE_SUB;

        continue;

      }

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

      {

        info[i].myanmar_position() = pos;

        continue;

      }

      if (pos == POS_BELOW_C && info[i].myanmar_category() != OT_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);

}

static void

initial_reordering_syllable (const hb_ot_shape_plan_t *plan,

                             hb_face_t *face,

                             hb_buffer_t *buffer,

                             unsigned int start, unsigned int end)

{

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

  switch (syllable_type) {

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

    case consonant_syllable:

      initial_reordering_consonant_syllable  (buffer, start, end);

      break;

    case punctuation_cluster:

    case non_myanmar_cluster:

      break;

  }

}

static inline void

insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED,

                       hb_font_t *font,

                       hb_buffer_t *buffer)

{

  /* Note: This loop is extra overhead, but should not be measurable. */

  bool has_broken_syllables = false;

  unsigned int count = buffer->len;

  hb_glyph_info_t *info = buffer->info;

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

    if ((info[i].syllable() & 0x0F) == broken_cluster)

    {

      has_broken_syllables = true;

      break;

    }

  if (likely (!has_broken_syllables))

    return;

  hb_codepoint_t dottedcircle_glyph;

  if (!font->get_nominal_glyph (0x25CCu, &dottedcircle_glyph))

    return;

  hb_glyph_info_t dottedcircle = {0};

  dottedcircle.codepoint = 0x25CCu;

  set_myanmar_properties (dottedcircle);

  dottedcircle.codepoint = dottedcircle_glyph;

  buffer->clear_output ();

  buffer->idx = 0;

  unsigned int last_syllable = 0;

  {

    unsigned int syllable = buffer->cur().syllable();

    syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F);

    if (unlikely (last_syllable != syllable && syllable_type == broken_cluster))

    {

      last_syllable = syllable;

      hb_glyph_info_t ginfo = dottedcircle;

      ginfo.cluster = buffer->cur().cluster;

      ginfo.mask = buffer->cur().mask;

      ginfo.syllable() = buffer->cur().syllable();

      buffer->output_info (ginfo);

    }

    else

      buffer->next_glyph ();

  }

  buffer->swap_buffers ();

}

static void

initial_reordering (const hb_ot_shape_plan_t *plan,

                    hb_font_t *font,

                    hb_buffer_t *buffer)

{

  insert_dotted_circles (plan, font, buffer);

  foreach_syllable (buffer, start, end)

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

}

static void

final_reordering (const hb_ot_shape_plan_t *plan,

                  hb_font_t *font HB_UNUSED,

                  hb_buffer_t *buffer)

{

  hb_glyph_info_t *info = buffer->info;

  unsigned int count = buffer->len;

  /* Zero syllables now... */

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

    info[i].syllable() = 0;

  HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_category);

  HB_BUFFER_DEALLOCATE_VAR (buffer, myanmar_position);

}

/* Uniscribe seems to have a shaper for 'mymr' that is like the

 * generic shaper, except that it zeros mark advances GDEF_LATE. */

const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar_old =

{

  nullptr, /* collect_features */

  nullptr, /* override_features */

  nullptr, /* data_create */

  nullptr, /* data_destroy */

  nullptr, /* preprocess_text */

  nullptr, /* postprocess_glyphs */

  HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,

  nullptr, /* decompose */

  nullptr, /* compose */

  nullptr, /* setup_masks */

  nullptr, /* disable_otl */

  nullptr, /* reorder_marks */

  HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,

  true, /* fallback_position */

};

const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar =

{

  collect_features_myanmar,

  override_features_myanmar,

  nullptr, /* data_create */

  nullptr, /* data_destroy */

  nullptr, /* preprocess_text */

  nullptr, /* postprocess_glyphs */

  HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,

  nullptr, /* decompose */

  nullptr, /* compose */

  setup_masks_myanmar,

  nullptr, /* disable_otl */

  nullptr, /* reorder_marks */

  HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,

  false, /* fallback_position */

};