/*

 * Copyright © 2011  Martin Hosken

 * Copyright © 2011  SIL International

 * Copyright © 2011,2012  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"

#ifdef HAVE_GRAPHITE2

#include "hb-shaper-impl.hh"

#include "hb-graphite2.h"

#include <graphite2/Segment.h>

#include "hb-ot-layout.h"

/**

 * SECTION:hb-graphite2

 * @title: hb-graphite2

 * @short_description: Graphite2 integration

 * @include: hb-graphite2.h

 *

 * Functions for using HarfBuzz with fonts that include Graphite features.

 * 

 * For Graphite features to work, you must be sure that HarfBuzz was compiled

 * with the `graphite2` shaping engine enabled. Currently, the default is to

 * not enable `graphite2` shaping.

 **/

/*

 * shaper face data

 */

typedef struct hb_graphite2_tablelist_t

{

  struct hb_graphite2_tablelist_t *next;

  hb_blob_t *blob;

  unsigned int tag;

} hb_graphite2_tablelist_t;

struct hb_graphite2_face_data_t

{

  hb_face_t *face;

  gr_face   *grface;

  hb_atomic_t<hb_graphite2_tablelist_t *> tlist;

};

static const void *hb_graphite2_get_table (const void *data, unsigned int tag, size_t *len)

{

  hb_graphite2_face_data_t *face_data = (hb_graphite2_face_data_t *) data;

  hb_graphite2_tablelist_t *tlist = face_data->tlist;

  hb_blob_t *blob = nullptr;

  for (hb_graphite2_tablelist_t *p = tlist; p; p = p->next)

    if (p->tag == tag) {

      blob = p->blob;

      break;

    }

  if (unlikely (!blob))

  {

    blob = face_data->face->reference_table (tag);

    hb_graphite2_tablelist_t *p = (hb_graphite2_tablelist_t *) hb_calloc (1, sizeof (hb_graphite2_tablelist_t));

    if (unlikely (!p)) {

      hb_blob_destroy (blob);

      return nullptr;

    }

    p->blob = blob;

    p->tag = tag;

retry:

    hb_graphite2_tablelist_t *tlist = face_data->tlist;

    p->next = tlist;

    if (unlikely (!face_data->tlist.cmpexch (tlist, p)))

      goto retry;

  }

  unsigned int tlen;

  const char *d = hb_blob_get_data (blob, &tlen);

  *len = tlen;

  return d;

}

hb_graphite2_face_data_t *

_hb_graphite2_shaper_face_data_create (hb_face_t *face)

{

  hb_blob_t *silf_blob = face->reference_table (HB_GRAPHITE2_TAG_SILF);

  /* Umm, we just reference the table to check whether it exists.

   * Maybe add better API for this? */

  if (!hb_blob_get_length (silf_blob))

  {

    hb_blob_destroy (silf_blob);

    return nullptr;

  }

  hb_blob_destroy (silf_blob);

  hb_graphite2_face_data_t *data = (hb_graphite2_face_data_t *) hb_calloc (1, sizeof (hb_graphite2_face_data_t));

  if (unlikely (!data))

    return nullptr;

  data->face = face;

  const gr_face_ops ops = {sizeof(gr_face_ops), &hb_graphite2_get_table, NULL};

  data->grface = gr_make_face_with_ops (data, &ops, gr_face_preloadAll);

  if (unlikely (!data->grface)) {

    hb_free (data);

    return nullptr;

  }

  return data;

}

void

_hb_graphite2_shaper_face_data_destroy (hb_graphite2_face_data_t *data)

{

  hb_graphite2_tablelist_t *tlist = data->tlist;

  while (tlist)

  {

    hb_graphite2_tablelist_t *old = tlist;

    hb_blob_destroy (tlist->blob);

    tlist = tlist->next;

    hb_free (old);

  }

  gr_face_destroy (data->grface);

  hb_free (data);

}

/**

 * hb_graphite2_face_get_gr_face: (skip)

 * @face: @hb_face_t to query

 *

 * Fetches the Graphite2 gr_face corresponding to the specified

 * #hb_face_t face object.

 *

 * Return value: the gr_face found

 *

 * Since: 0.9.10

 */

gr_face *

hb_graphite2_face_get_gr_face (hb_face_t *face)

{

  const hb_graphite2_face_data_t *data = face->data.graphite2;

  return data ? data->grface : nullptr;

}

/*

 * shaper font data

 */

struct hb_graphite2_font_data_t {};

hb_graphite2_font_data_t *

_hb_graphite2_shaper_font_data_create (hb_font_t *font HB_UNUSED)

{

  return (hb_graphite2_font_data_t *) HB_SHAPER_DATA_SUCCEEDED;

}

void

_hb_graphite2_shaper_font_data_destroy (hb_graphite2_font_data_t *data HB_UNUSED)

{

}

#ifndef HB_DISABLE_DEPRECATED

/**

 * hb_graphite2_font_get_gr_font: (skip)

 * @font: An #hb_font_t

 *

 * Always returns `NULL`. Use hb_graphite2_face_get_gr_face() instead.

 *

 * Return value: (nullable): Graphite2 font associated with @font.

 *

 * Since: 0.9.10

 * Deprecated: 1.4.2

 */

gr_font *

hb_graphite2_font_get_gr_font (hb_font_t *font HB_UNUSED)

{

  return nullptr;

}

#endif

/*

 * shaper

 */

struct hb_graphite2_cluster_t {

  unsigned int base_char;

  unsigned int num_chars;

  unsigned int base_glyph;

  unsigned int num_glyphs;

  unsigned int cluster;

  int advance;

};

hb_bool_t

_hb_graphite2_shape (hb_shape_plan_t    *shape_plan HB_UNUSED,

         hb_font_t          *font,

         hb_buffer_t        *buffer,

         const hb_feature_t *features,

         unsigned int        num_features)

{

  hb_face_t *face = font->face;

  gr_face *grface = face->data.graphite2->grface;

  const char *lang = hb_language_to_string (hb_buffer_get_language (buffer));

  const char *lang_end = lang ? strchr (lang, '-') : nullptr;

  int lang_len = lang_end ? lang_end - lang : -1;

  gr_feature_val *feats = gr_face_featureval_for_lang (grface, lang ? hb_tag_from_string (lang, lang_len) : 0);

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

  {

    const gr_feature_ref *fref = gr_face_find_fref (grface, features[i].tag);

    if (fref)

      gr_fref_set_feature_value (fref, features[i].value, feats);

  }

  hb_direction_t direction = buffer->props.direction;

  hb_direction_t horiz_dir = hb_script_get_horizontal_direction (buffer->props.script);

  /* TODO vertical:

   * The only BTT vertical script is Ogham, but it's not clear to me whether OpenType

   * Ogham fonts are supposed to be implemented BTT or not.  Need to research that

   * first. */

  if ((HB_DIRECTION_IS_HORIZONTAL (direction) &&

       direction != horiz_dir && horiz_dir != HB_DIRECTION_INVALID) ||

      (HB_DIRECTION_IS_VERTICAL   (direction) &&

       direction != HB_DIRECTION_TTB))

  {

    hb_buffer_reverse_clusters (buffer);

    direction = HB_DIRECTION_REVERSE (direction);

  }

  gr_segment *seg = nullptr;

  const gr_slot *is;

  unsigned int ci = 0, ic = 0;

  unsigned int curradvx = 0, curradvy = 0;

  unsigned int scratch_size;

  hb_buffer_t::scratch_buffer_t *scratch = buffer->get_scratch_buffer (&scratch_size);

  uint32_t *chars = (uint32_t *) scratch;

  for (unsigned int i = 0; i < buffer->len; ++i)

    chars[i] = buffer->info[i].codepoint;

  seg = gr_make_seg (nullptr, grface,

         HB_TAG_NONE, // https://github.com/harfbuzz/harfbuzz/issues/3439#issuecomment-1442650148

         feats,

         gr_utf32, chars, buffer->len,

         2 | (direction == HB_DIRECTION_RTL ? 1 : 0));

  if (unlikely (!seg)) {

    if (feats) gr_featureval_destroy (feats);

    return false;

  }

  unsigned int glyph_count = gr_seg_n_slots (seg);

  if (unlikely (!glyph_count)) {

    if (feats) gr_featureval_destroy (feats);

    gr_seg_destroy (seg);

    buffer->len = 0;

    return true;

  }

  (void) buffer->ensure (glyph_count);

  scratch = buffer->get_scratch_buffer (&scratch_size);

  while ((DIV_CEIL (sizeof (hb_graphite2_cluster_t) * buffer->len, sizeof (*scratch)) +

    DIV_CEIL (sizeof (hb_codepoint_t) * glyph_count, sizeof (*scratch))) > scratch_size)

  {

    if (unlikely (!buffer->ensure (buffer->allocated * 2)))

    {

      if (feats) gr_featureval_destroy (feats);

      gr_seg_destroy (seg);

      return false;

    }

    scratch = buffer->get_scratch_buffer (&scratch_size);

  }

#define ALLOCATE_ARRAY(Type, name, len) \

  Type *name = (Type *) scratch; \

  do { \

    unsigned int _consumed = DIV_CEIL ((len) * sizeof (Type), sizeof (*scratch)); \

    assert (_consumed <= scratch_size); \

    scratch += _consumed; \

    scratch_size -= _consumed; \

  } while (0)

  ALLOCATE_ARRAY (hb_graphite2_cluster_t, clusters, buffer->len);

  ALLOCATE_ARRAY (hb_codepoint_t, gids, glyph_count);

#undef ALLOCATE_ARRAY

  hb_memset (clusters, 0, sizeof (clusters[0]) * buffer->len);

  hb_codepoint_t *pg = gids;

  clusters[0].cluster = buffer->info[0].cluster;

  unsigned int upem = hb_face_get_upem (face);

  float xscale = (float) font->x_scale / upem;

  float yscale = (float) font->y_scale / upem;

  yscale *= yscale / xscale;

  unsigned int curradv = 0;

  if (HB_DIRECTION_IS_BACKWARD (direction))

  {

    curradv = gr_slot_origin_X(gr_seg_first_slot(seg)) * xscale;

    clusters[0].advance = gr_seg_advance_X(seg) * xscale - curradv;

  }

  else

    clusters[0].advance = 0;

  for (is = gr_seg_first_slot (seg), ic = 0; is; is = gr_slot_next_in_segment (is), ic++)

  {

    unsigned int before = gr_slot_before (is);

    unsigned int after = gr_slot_after (is);

    *pg = gr_slot_gid (is);

    pg++;

    while (clusters[ci].base_char > before && ci)

    {

      clusters[ci-1].num_chars += clusters[ci].num_chars;

      clusters[ci-1].num_glyphs += clusters[ci].num_glyphs;

      clusters[ci-1].advance += clusters[ci].advance;

      ci--;

    }

    if (gr_slot_can_insert_before (is) && clusters[ci].num_chars && before >= clusters[ci].base_char + clusters[ci].num_chars)

    {

      hb_graphite2_cluster_t *c = clusters + ci + 1;

      c->base_char = clusters[ci].base_char + clusters[ci].num_chars;

      c->cluster = buffer->info[c->base_char].cluster;

      c->num_chars = before - c->base_char;

      c->base_glyph = ic;

      c->num_glyphs = 0;

      if (HB_DIRECTION_IS_BACKWARD (direction))

      {

  c->advance = curradv - gr_slot_origin_X(is) * xscale;

  curradv -= c->advance;

      }

      else

      {

  auto origin_X = gr_slot_origin_X (is) * xscale;

  c->advance = 0;

  clusters[ci].advance += origin_X - curradv;

  curradv = origin_X;

      }

      ci++;

    }

    clusters[ci].num_glyphs++;

    if (clusters[ci].base_char + clusters[ci].num_chars < after + 1)

  clusters[ci].num_chars = after + 1 - clusters[ci].base_char;

  }

  if (HB_DIRECTION_IS_BACKWARD (direction))

    clusters[ci].advance += curradv;

  else

    clusters[ci].advance += gr_seg_advance_X(seg) * xscale - curradv;

  ci++;

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

  {

    for (unsigned int j = 0; j < clusters[i].num_glyphs; ++j)

    {

      hb_glyph_info_t *info = &buffer->info[clusters[i].base_glyph + j];

      info->codepoint = gids[clusters[i].base_glyph + j];

      info->cluster = clusters[i].cluster;

      info->var1.i32 = clusters[i].advance;     // all glyphs in the cluster get the same advance

    }

  }

  buffer->len = glyph_count;

  /* Positioning. */

  unsigned int currclus = UINT_MAX;

  const hb_glyph_info_t *info = buffer->info;

  hb_glyph_position_t *pPos = hb_buffer_get_glyph_positions (buffer, nullptr);

  if (!HB_DIRECTION_IS_BACKWARD (direction))

  {

    curradvx = 0;

    for (is = gr_seg_first_slot (seg); is; pPos++, ++info, is = gr_slot_next_in_segment (is))

    {

      pPos->x_offset = gr_slot_origin_X (is) * xscale - curradvx;

      pPos->y_offset = gr_slot_origin_Y (is) * yscale - curradvy;

      if (info->cluster != currclus) {

  pPos->x_advance = info->var1.i32;

  curradvx += pPos->x_advance;

  currclus = info->cluster;

      } else

  pPos->x_advance = 0.;

      pPos->y_advance = gr_slot_advance_Y (is, grface, nullptr) * yscale;

      curradvy += pPos->y_advance;

    }

  }

  else

  {

    curradvx = gr_seg_advance_X(seg) * xscale;

    for (is = gr_seg_first_slot (seg); is; pPos++, info++, is = gr_slot_next_in_segment (is))

    {

      if (info->cluster != currclus)

      {

  pPos->x_advance = info->var1.i32;

  curradvx -= pPos->x_advance;

  currclus = info->cluster;

      } else

  pPos->x_advance = 0.;

      pPos->y_advance = gr_slot_advance_Y (is, grface, nullptr) * yscale;

      curradvy -= pPos->y_advance;

      pPos->x_offset = gr_slot_origin_X (is) * xscale - info->var1.i32 - curradvx + pPos->x_advance;

      pPos->y_offset = gr_slot_origin_Y (is) * yscale - curradvy;

    }

    hb_buffer_reverse_clusters (buffer);

  }

  if (feats) gr_featureval_destroy (feats);

  gr_seg_destroy (seg);

  buffer->clear_glyph_flags ();

  buffer->unsafe_to_break ();

  return true;

}

#endif