#ifndef OT_GLYF_SIMPLEGLYPH_HH

#define OT_GLYF_SIMPLEGLYPH_HH

#include "../../hb-open-type.hh"

namespace OT {

namespace glyf_impl {

struct SimpleGlyph

{

  enum simple_glyph_flag_t

  {

    FLAG_ON_CURVE       = 0x01,

    FLAG_X_SHORT        = 0x02,

    FLAG_Y_SHORT        = 0x04,

    FLAG_REPEAT         = 0x08,

    FLAG_X_SAME         = 0x10,

    FLAG_Y_SAME         = 0x20,

    FLAG_OVERLAP_SIMPLE = 0x40,

    FLAG_CUBIC          = 0x80

  };

  const GlyphHeader &header;

  hb_bytes_t bytes;

  SimpleGlyph (const GlyphHeader &header_, hb_bytes_t bytes_) :

    header (header_), bytes (bytes_) {}

  unsigned int instruction_len_offset () const

  { return GlyphHeader::static_size + 2 * header.numberOfContours; }

  unsigned int length (unsigned int instruction_len) const

  { return instruction_len_offset () + 2 + instruction_len; }

  bool has_instructions_length () const

  {

    return instruction_len_offset () + 2 <= bytes.length;

  }

  unsigned int instructions_length () const

  {

    unsigned int instruction_length_offset = instruction_len_offset ();

    if (unlikely (instruction_length_offset + 2 > bytes.length)) return 0;

    const HBUINT16 &instructionLength = StructAtOffset<HBUINT16> (&bytes, instruction_length_offset);

    /* Out of bounds of the current glyph */

    if (unlikely (length (instructionLength) > bytes.length)) return 0;

    return instructionLength;

  }

  const hb_bytes_t trim_padding () const

  {

    /* based on FontTools _g_l_y_f.py::trim */

    const uint8_t *glyph = (uint8_t*) bytes.arrayZ;

    const uint8_t *glyph_end = glyph + bytes.length;

    /* simple glyph w/contours, possibly trimmable */

    glyph += instruction_len_offset ();

    if (unlikely (glyph + 2 >= glyph_end)) return hb_bytes_t ();

    unsigned int num_coordinates = StructAtOffset<HBUINT16> (glyph - 2, 0) + 1;

    unsigned int num_instructions = StructAtOffset<HBUINT16> (glyph, 0);

    glyph += 2 + num_instructions;

    unsigned int coord_bytes = 0;

    unsigned int coords_with_flags = 0;

    while (glyph < glyph_end)

    {

      uint8_t flag = *glyph;

      glyph++;

      unsigned int repeat = 1;

      if (flag & FLAG_REPEAT)

      {

  if (unlikely (glyph >= glyph_end)) return hb_bytes_t ();

  repeat = *glyph + 1;

  glyph++;

      }

      unsigned int xBytes, yBytes;

      xBytes = yBytes = 0;

      if (flag & FLAG_X_SHORT) xBytes = 1;

      else if ((flag & FLAG_X_SAME) == 0) xBytes = 2;

      if (flag & FLAG_Y_SHORT) yBytes = 1;

      else if ((flag & FLAG_Y_SAME) == 0) yBytes = 2;

      coord_bytes += (xBytes + yBytes) * repeat;

      coords_with_flags += repeat;

      if (coords_with_flags >= num_coordinates) break;

    }

    if (unlikely (coords_with_flags != num_coordinates)) return hb_bytes_t ();

    return bytes.sub_array (0, bytes.length + coord_bytes - (glyph_end - glyph));

  }

  /* zero instruction length */

  void drop_hints ()

  {

    if (!has_instructions_length ()) return;

    GlyphHeader &glyph_header = const_cast<GlyphHeader &> (header);

    (HBUINT16 &) StructAtOffset<HBUINT16> (&glyph_header, instruction_len_offset ()) = 0;

  }

  void drop_hints_bytes (hb_bytes_t &dest_start, hb_bytes_t &dest_end) const

  {

    unsigned int instructions_len = instructions_length ();

    unsigned int glyph_length = length (instructions_len);

    dest_start = bytes.sub_array (0, glyph_length - instructions_len);

    dest_end = bytes.sub_array (glyph_length, bytes.length - glyph_length);

  }

  void set_overlaps_flag ()

  {

    if (unlikely (!header.numberOfContours)) return;

    unsigned flags_offset = length (instructions_length ());

    if (unlikely (flags_offset + 1 > bytes.length)) return;

    HBUINT8 &first_flag = (HBUINT8 &) StructAtOffset<HBUINT16> (&bytes, flags_offset);

    first_flag = (uint8_t) first_flag | FLAG_OVERLAP_SIMPLE;

  }

  static bool read_flags (const HBUINT8 *&p /* IN/OUT */,

        hb_array_t<contour_point_t> points_ /* IN/OUT */,

        const HBUINT8 *end)

  {

    auto *points = points_.arrayZ;

    unsigned count = points_.length;

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

    {

      if (unlikely (p + 1 > end)) return false;

      uint8_t flag = *p++;

      points[i++].flag = flag;

      if (flag & FLAG_REPEAT)

      {

  if (unlikely (p + 1 > end)) return false;

  unsigned int repeat_count = *p++;

  unsigned stop = hb_min (i + repeat_count, count);

  for (; i < stop; i++)

    points[i].flag = flag;

      }

    }

    return true;

  }

  static bool read_points (const HBUINT8 *&p /* IN/OUT */,

         hb_array_t<contour_point_t> points_ /* IN/OUT */,

         const HBUINT8 *end,

         float contour_point_t::*m,

         const simple_glyph_flag_t short_flag,

         const simple_glyph_flag_t same_flag)

  {

    int v = 0;

    for (auto &point : points_)

    {

      unsigned flag = point.flag;

      if (flag & short_flag)

      {

  if (unlikely (p + 1 > end)) return false;

  v += (bool(flag & same_flag) * 2 - 1) * *p++;

      }

      else

      {

  if (!(flag & same_flag))

  {

    if (unlikely (p + HBINT16::static_size > end)) return false;

    v += *(const HBINT16 *) p;

    p += HBINT16::static_size;

  }

      }

      point.*m = v;

    }

    return true;

  }

  bool get_contour_points (contour_point_vector_t &points /* OUT */,

         bool phantom_only = false) const

  {

    const HBUINT16 *endPtsOfContours = &StructAfter<HBUINT16> (header);

    int num_contours = header.numberOfContours;

    assert (num_contours > 0);

    /* One extra item at the end, for the instruction-count below. */

    if (unlikely (!bytes.check_range (&endPtsOfContours[num_contours]))) return false;

    unsigned int num_points = endPtsOfContours[num_contours - 1] + 1;

    unsigned old_length = points.length;

    points.alloc (points.length + num_points + 4); // Allocate for phantom points, to avoid a possible copy

    if (unlikely (!points.resize (points.length + num_points, false))) return false;

    auto points_ = points.as_array ().sub_array (old_length);

    if (!phantom_only)

      hb_memset (points_.arrayZ, 0, sizeof (contour_point_t) * num_points);

    if (phantom_only) return true;

    for (int i = 0; i < num_contours; i++)

      points_[endPtsOfContours[i]].is_end_point = true;

    /* Skip instructions */

    const HBUINT8 *p = &StructAtOffset<HBUINT8> (&endPtsOfContours[num_contours + 1],

             endPtsOfContours[num_contours]);

    if (unlikely ((const char *) p < bytes.arrayZ)) return false; /* Unlikely overflow */

    const HBUINT8 *end = (const HBUINT8 *) (bytes.arrayZ + bytes.length);

    if (unlikely (p >= end)) return false;

    /* Read x & y coordinates */

    return read_flags (p, points_, end)

        && read_points (p, points_, end, &contour_point_t::x,

      FLAG_X_SHORT, FLAG_X_SAME)

  && read_points (p, points_, end, &contour_point_t::y,

      FLAG_Y_SHORT, FLAG_Y_SAME);

  }

  static void encode_coord (int value,

                            unsigned &flag,

                            const simple_glyph_flag_t short_flag,

                            const simple_glyph_flag_t same_flag,

                            hb_vector_t<uint8_t> &coords /* OUT */)

  {

    if (value == 0)

    {

      flag |= same_flag;

    }

    else if (value >= -255 && value <= 255)

    {

      flag |= short_flag;

      if (value > 0) flag |= same_flag;

      else value = -value;

      coords.arrayZ[coords.length++] = (uint8_t) value;

    }

    else

    {

      int16_t val = value;

      coords.arrayZ[coords.length++] = val >> 8;

      coords.arrayZ[coords.length++] = val & 0xff;

    }

  }

  static void encode_flag (unsigned flag,

                           unsigned &repeat,

                           unsigned lastflag,

                           hb_vector_t<uint8_t> &flags /* OUT */)

  {

    if (flag == lastflag && repeat != 255)

    {

      repeat++;

      if (repeat == 1)

      {

        /* We know there's room. */

        flags.arrayZ[flags.length++] = flag;

      }

      else

      {

        unsigned len = flags.length;

        flags.arrayZ[len-2] = flag | FLAG_REPEAT;

        flags.arrayZ[len-1] = repeat;

      }

    }

    else

    {

      repeat = 0;

      flags.arrayZ[flags.length++] = flag;

    }

  }

  bool compile_bytes_with_deltas (const contour_point_vector_t &all_points,

                                  bool no_hinting,

                                  hb_bytes_t &dest_bytes /* OUT */)

  {

    if (header.numberOfContours == 0 || all_points.length <= 4)

    {

      dest_bytes = hb_bytes_t ();

      return true;

    }

    unsigned num_points = all_points.length - 4;

    hb_vector_t<uint8_t> flags, x_coords, y_coords;

    if (unlikely (!flags.alloc_exact (num_points))) return false;

    if (unlikely (!x_coords.alloc_exact (2*num_points))) return false;

    if (unlikely (!y_coords.alloc_exact (2*num_points))) return false;

    unsigned lastflag = 255, repeat = 0;

    int prev_x = 0, prev_y = 0;

    for (unsigned i = 0; i < num_points; i++)

    {

      unsigned flag = all_points.arrayZ[i].flag;

      flag &= FLAG_ON_CURVE | FLAG_OVERLAP_SIMPLE | FLAG_CUBIC;

      int cur_x = roundf (all_points.arrayZ[i].x);

      int cur_y = roundf (all_points.arrayZ[i].y);

      encode_coord (cur_x - prev_x, flag, FLAG_X_SHORT, FLAG_X_SAME, x_coords);

      encode_coord (cur_y - prev_y, flag, FLAG_Y_SHORT, FLAG_Y_SAME, y_coords);

      encode_flag (flag, repeat, lastflag, flags);

      prev_x = cur_x;

      prev_y = cur_y;

      lastflag = flag;

    }

    unsigned len_before_instrs = 2 * header.numberOfContours + 2;

    unsigned len_instrs = instructions_length ();

    unsigned total_len = len_before_instrs + flags.length + x_coords.length + y_coords.length;

    if (!no_hinting)

      total_len += len_instrs;

    char *p = (char *) hb_malloc (total_len);

    if (unlikely (!p)) return false;

    const char *src = bytes.arrayZ + GlyphHeader::static_size;

    char *cur = p;

    hb_memcpy (p, src, len_before_instrs);

    cur += len_before_instrs;

    src += len_before_instrs;

    if (!no_hinting)

    {

      hb_memcpy (cur, src, len_instrs);

      cur += len_instrs;

    }

    hb_memcpy (cur, flags.arrayZ, flags.length);

    cur += flags.length;

    hb_memcpy (cur, x_coords.arrayZ, x_coords.length);

    cur += x_coords.length;

    hb_memcpy (cur, y_coords.arrayZ, y_coords.length);

    dest_bytes = hb_bytes_t (p, total_len);

    return true;

  }

};

} /* namespace glyf_impl */

} /* namespace OT */

#endif /* OT_GLYF_SIMPLEGLYPH_HH */