internal
u32 mem_edit_bg_color_fn(const u8 *data, u64 off, const void *user_data)
{
  const RNTuple_Info *ntinfo = reinterpret_cast<const RNTuple_Info *>(user_data);

  if (ntinfo->header.start <= off && off <= ntinfo->header.end())
    return IM_COL32(200, 0, 50, 255);
  if (ntinfo->footer.start <= off && off <= ntinfo->footer.end())
    return IM_COL32(50, 0, 200, 255);
  return IM_COL32(0, 0, 0, 0);
}

internal
MemoryEditor make_memory_editor(const RNTuple_Info &ntpl_info)
{
  MemoryEditor mem_edit;
  // mem_edit.ReadOnly = true;
  mem_edit.Cols = 32;
  mem_edit.BgColorFn = mem_edit_bg_color_fn;
  mem_edit.BgColorFnUserData = &ntpl_info;
  return mem_edit;
}

internal
void update_and_render(Arena *arena, App_State &app, f32 delta_time)
{
  (void)delta_time;
  
  ImGui::SetNextWindowPos({ 0, 0 });
  ImGui::SetNextWindowSize({ (f32)app.win_data.width, (f32)app.win_data.height });

  Temp scratch = temp_begin(arena);
  defer { temp_end(scratch); };

  const u64 inspected_max_size = 2048;
  u64 text_buf_size = min(app.inspected_file_size * 2, inspected_max_size);
  char *text_buf = arena_push_array_no_zero<char>(scratch.arena, text_buf_size + 1);
  // Convert file content to human readable
  // @Speed: maybe do this only when the file changes
  for (u64 i = 0; i < text_buf_size / 2; ++i)
    sprintf(&text_buf[2 * i], "%02X", app.inspected_fmem[i]);
  text_buf[text_buf_size] = 0;
  
  if (ImGui::Begin("main")) {
    ImGui::Text("Inspecting RNTuple '%s' (%s)", app.ntpl_name, 
                (const char *)rntuple_description(scratch.arena, app.rntinfo->anchor));

    static MemoryEditor mem_edit = make_memory_editor(*app.rntinfo);
    mem_edit.DrawWindow("Hex View", app.inspected_fmem, app.inspected_file_size);
    
    ImGui::End();
  }
}