#include <assert.h>
#include <stdio.h>
#include <stdint.h>

#include <ft2build.h>
#include FT_FREETYPE_H

#include <SDL3/SDL.h>

#include <libserialport.h>

struct glyph {
  int32_t width;
  int32_t height;

  int32_t horiBearingX;
  int32_t horiBearingY;
  int32_t horiAdvance;

  SDL_Texture * texture;
};

static struct glyph glyphs[0x80 - 0x20] = {0};
int32_t face_height;

int
load_outline_char(SDL_Renderer * renderer,
		  const FT_Face face,
                  const FT_Int32 load_flags,
                  const FT_Render_Mode render_mode,
                  const FT_ULong char_code)
{
  FT_Error error;
  FT_UInt glyph_index = FT_Get_Char_Index(face, char_code);

  error = FT_Load_Glyph(face, glyph_index, load_flags);
  if (error) {
    printf("FT_Load_Glyph %s\n", FT_Error_String(error));
    return -1;
  }

  error = FT_Render_Glyph(face->glyph, render_mode);
  if (error) {
    printf("FT_Render_Glyph %s\n", FT_Error_String(error));
    return -1;
  }

  struct glyph * glyph = &glyphs[char_code - 0x20];

  glyph->width = face->glyph->bitmap.width;
  glyph->height = face->glyph->bitmap.rows;
  glyph->horiBearingX = face->glyph->metrics.horiBearingX;
  glyph->horiBearingY = face->glyph->metrics.horiBearingY;
  glyph->horiAdvance = face->glyph->metrics.horiAdvance;

  if (face->glyph->bitmap.pitch != 0) {
    SDL_Surface * surface = SDL_CreateSurface(face->glyph->bitmap.width,
					      face->glyph->bitmap.rows,
					      SDL_PIXELFORMAT_RGBA8888);

    SDL_LockSurface(surface);

    for (int y = 0; y < face->glyph->bitmap.rows; y++) {
      for (int x = 0; x < face->glyph->bitmap.width; x++) {
	int s_ix = y * face->glyph->bitmap.pitch + x;
	int d_ix = y * surface->pitch + x * 4;
	uint8_t gray = face->glyph->bitmap.buffer[s_ix];
	((uint8_t *)surface->pixels)[d_ix + 0] = gray;
	((uint8_t *)surface->pixels)[d_ix + 1] = gray;
	((uint8_t *)surface->pixels)[d_ix + 2] = gray;
	((uint8_t *)surface->pixels)[d_ix + 3] = 255;
      }
    }

    SDL_UnlockSurface(surface);

    if (glyph->texture != NULL)
      SDL_DestroyTexture(glyph->texture);
    glyph->texture = SDL_CreateTextureFromSurface(renderer, surface);
    if (glyph->texture == NULL) {
      printf("%s\n", SDL_GetError());
    }
    assert(glyph->texture != NULL);

    SDL_DestroySurface(surface);
  }

  return 0;
}

int load_font(SDL_Renderer * renderer, int font_size)
{
  FT_Library library;
  FT_Face face;
  FT_Error error;

  error = FT_Init_FreeType(&library);
  if (error) {
    printf("FT_Init_FreeType\n");
    return -1;
  }

  error = FT_New_Face(library, "DejaVuSansMono.ttf", 0, &face);
  if (error) {
    printf("FT_New_Face\n");
    return -1;
  }

  error = FT_Set_Pixel_Sizes(face, 0, font_size);
  if (error) {
    printf("FT_Set_Pixel_Sizes: %s %d\n", FT_Error_String(error), error);
    return -1;
  }

  for (int char_code = 0x20; char_code <= 0x7f; char_code++) {
    load_outline_char(renderer, face, FT_LOAD_DEFAULT, FT_RENDER_MODE_NORMAL, char_code);
  }

  printf("loaded size %ld\n", face->size->metrics.height >> 6);
  face_height = face->size->metrics.height;

  return 0;
}

void render(SDL_Renderer * renderer, int window_width, int window_height, const char * s, int length)
{
  int32_t advance = (window_width - (window_width * 5 / 100)) << 6;
  for (int i = (length - 1); i >= 0; i--) {
    char c = s[i];
    struct glyph * glyph = &glyphs[c - 0x20];
    advance -= glyph->horiAdvance;
    if (glyph->texture != NULL) {
      float x = (float)(advance + glyph->horiBearingX) / 64.f;
      float y = (window_height / 2) + (face_height >> 6) / 3 + (float)(-glyph->horiBearingY) / 64.f;
      SDL_FRect srect = {
	.x = 0.f,
	.y = 0.f,
	.w = glyph->width,
	.h = glyph->height
      };
      SDL_FRect drect = {
	.x = x,
	.y = y,
	.w = glyph->width,
	.h = glyph->height
      };
      SDL_RenderTexture(renderer, glyph->texture, &srect, &drect);
    }
  }
}

int max(int a, int b) {
  return a > b ? a : b;
}

int main()
{
  int ret;
  SDL_Window * window;
  SDL_Renderer * renderer;

  ret = SDL_Init(SDL_INIT_VIDEO);
  assert(ret == 0);

  window = SDL_CreateWindow("timer",
			    512, // w
			    512, // h
			    SDL_WINDOW_RESIZABLE);// | SDL_WINDOW_MAXIMIZED);

  renderer = SDL_CreateRenderer(window, NULL);
  SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);

  SDL_PropertiesID props = SDL_GetRendererProperties(renderer);

  const char * name = SDL_GetRendererName(renderer);
  assert(name != NULL);
  printf("renderer: %s\n", name);
  const SDL_PixelFormatEnum * formats = SDL_GetProperty(props, SDL_PROP_RENDERER_TEXTURE_FORMATS_POINTER, NULL);
  assert(formats != NULL);
  while (*formats != SDL_PIXELFORMAT_UNKNOWN) {
    printf("%s\n", SDL_GetPixelFormatName(*formats++));
  }

  int last_width = -1;

  uint64_t ticks = SDL_GetTicks();
  const int min_length = 4;
  int max_length = min_length;

  /*
  */

  uint8_t read_buf[32] = {'7', '1', '.', '0', '1', '\r'};

  struct state state = {0};

  int i = 0;
  while (1) {
    i++;
    //enum sp_return sp_ret = sp_nonblocking_read(port, read_buf, (sizeof (read_buf)));
    enum sp_return sp_ret = 6;
    if (sp_ret < 0) {
      printf("sp_nonblocking_read error\n");
      break;
    }
    handle_state(read_buf, sp_ret, &state);

    char str_buf[16];
    switch (state.counter_state) {
    case COUNTER_STOPPED:
      snprintf(str_buf, (sizeof (str_buf)) - 1, "%d.%02d", state.time.whole, state.time.fraction);
      break;
    case COUNTER_RUNNING:
      {
	uint64_t counter = SDL_GetPerformanceCounter();
	uint64_t frequency = SDL_GetPerformanceFrequency();
	double duration = (((double)counter) - ((double)state.counter)) / ((double)frequency);

	snprintf(str_buf, (sizeof (str_buf)) - 1, "%.02f", duration);
      }
      break;
    default:
      str_buf[0] = 0;
      break;
    }
    int length = strlen(str_buf);

    SDL_RenderClear(renderer);
    int window_width;
    int window_height;
    ret = SDL_GetWindowSizeInPixels(window, &window_width, &window_height);
    assert(ret == 0);
    if ((window_width != last_width) || (length > max_length)) {
      max_length = max(min_length, length);
      last_width = window_width;

      int divisor = max(1, (max_length * 8 / 10));
      int font_size = (window_width * 95 / 100) / divisor;
      printf("fs %d %d %d\n", font_size, window_width, max_length);
      load_font(renderer, font_size);
    }

    render(renderer, window_width, window_height, str_buf, length);

    while (SDL_GetTicks() - ticks < (1000 / 60)) { SDL_Delay(1); }
    SDL_RenderPresent(renderer);
    ticks = SDL_GetTicks();

    SDL_Event event;
    while (SDL_PollEvent(&event)) {
      switch (event.type) {
      case SDL_EVENT_QUIT:
	goto exit;
      case SDL_EVENT_KEY_DOWN:
	if (event.key.keysym.sym == SDLK_ESCAPE)
	  goto exit;
	break;
      default:
	break;
      }


    }
  }

 exit:
  SDL_DestroyRenderer(renderer);
  SDL_DestroyWindow(window);
  SDL_Quit();
}