#pragma once

#include <ft2build.h>
#include <vector>
#include FT_FREETYPE_H

#include "shader.h"
#include "types.h"

struct TextVertex {
  float x, y, s, t, r, g, b;
};

/* State of a single charactrer glyph. */
struct character {
  int size[2];
  int bearing[2];
  unsigned int advance;
  float tx, ty; /* x and y offset of glyph in texture atlas. */
  float tw, th; /* width and height of glyph in texture atlas. */
};

const int MAX_GLYPHS_PER_BATCH = 10000;
const int VERTICES_PER_GLYPH = 6;
const int MAX_VERTICES = MAX_GLYPHS_PER_BATCH * VERTICES_PER_GLYPH;

class TextRenderer {
public:
  TextRenderer(unsigned int screen_width, unsigned int screen_height);
  ~TextRenderer(void);

  void load_font(const char* font_path, unsigned int font_size);
  void render_text(const char* text, float x, float y, const Color& color);
  float get_text_width(const char* text, float scale);

  void begin(void);
  void flush(void);


private:
  Shader* _txt_shader;
  unsigned int _vao, _vbo;
  unsigned int _atlas_texture_id;
  character _chars[128];
  std::vector<TextVertex> _vertices;
  float _projecton[16];
};