#include "new.h"
#include "font_layout.h"

static inline size_t texture_offset(font * font)
{
  return (sizeof (struct font)) + (sizeof (struct glyph)) * font->glyph_count;
}

extern "C" void log(int);

void FontLayout::init(size_t buffer, int layout_buffer_length)
{
  this->font = reinterpret_cast<struct font *>(buffer + 0);
  this->glyphs = reinterpret_cast<struct glyph *>(buffer + (sizeof (struct font)));

  this->texture = reinterpret_cast<void *>(buffer + texture_offset(this->font));

  this->layout_buffer_length = layout_buffer_length;
  this->layout_buffer_index = 0;
  this->layout_buffer = New<LayoutBuffer>(layout_buffer_length);

  this->glyph_buffer = New<GlyphBuffer>(this->font->glyph_count);
  int o = 0;
  log(o);
  for (uint16_t i = 0; i < this->font->glyph_count; i++) {
    glyph_texture const & texture = this->glyphs[i].texture;
    this->glyph_buffer[i].texPosition.x = float(texture.x - o) / float(this->font->texture_width);
    this->glyph_buffer[i].texPosition.y = float(texture.y - o) / float(this->font->texture_height);
    this->glyph_buffer[i].texSize.x = float(texture.width - o) / float(this->font->texture_width);
    this->glyph_buffer[i].texSize.y = float(texture.height - o) / float(this->font->texture_height);
    this->glyph_buffer[i].size.x = float(texture.width);
    this->glyph_buffer[i].size.y = float(texture.height);
  }
}

void FontLayout::draw_string(char const * string)
{
  int i = 0;

  int32_t x = 0;
  int32_t y = 0;

  while (true) {
    char c = string[i++];
    if (c == 0)
      return;

    if (c < font->first_char_code || c > font->last_char_code) {
      continue;
    }
    int char_index = c - font->first_char_code;
    glyph const & glyph = glyphs[char_index];

    if (layout_buffer_index >= layout_buffer_length)
      return;

    int32_t bearingY = glyph.metrics.height - glyph.metrics.horiBearingY;
    XMFLOAT3 position {
      float(x + glyph.metrics.horiBearingX) * 0.015625f,
      float(y - bearingY) * 0.015625f,
      0.0f,
    };

    layout_buffer[layout_buffer_index].position = position;
    layout_buffer[layout_buffer_index].glyph_index = char_index;
    layout_buffer_index += 1;

    x += glyph.metrics.horiAdvance;
  }
}