/*
 * Copyright 2022 Frederico de Oliveira Linhares
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "candy_gear.h"
#include "color.h"
#include "core.h"
#include "font.h"
#include "graphic.h"
#include "key.h"
#include "log.h"
#include "palette.h"
#include "point.h"
#include "rect.h"
#include "sound.h"
#include "sprite.h"
#include "texture.h"

cg_sCore cg_core;

void handle_error(mrb_state *mrb)
{
    mrb_print_error(mrb);
    cg_core.quit_game = SDL_TRUE;
}

int main(int argc, char *argv[])
{
  SDL_Event event;
  Uint32 frame_start;

  mrb_state *mrb = mrb_open();
  mrb_value main_obj;
  mrb_sym sym_init, sym_key_down, sym_key_up, sym_quit, sym_tick;
  FILE *fp;

  LoaderStack core_loader;

  cg_core.config_file = argv[1];

  cg_Core_init(&core_loader);
  if(!cg_Core_load(&core_loader)) return 1;

  if (!mrb) { /* handle error */ }
  mrb_define_module(mrb, "CandyGear");
  cg_candy_gear_init(mrb);
  cg_color_init(mrb);
  cg_font_init(mrb);
  cg_graphic_init(mrb);
  cg_key_init(mrb);
  cg_log_init(mrb);
  cg_palette_init(mrb);
  cg_point_init(mrb);
  cg_rect_init(mrb);
  cg_sound_init(mrb);
  cg_sprite_init(mrb);
  cg_texture_init(mrb);

  main_obj = mrb_obj_iv_inspect(mrb, mrb->top_self);
  sym_init = mrb_intern_cstr(mrb, "init");
  sym_key_down = mrb_intern_cstr(mrb, "key_down");
  sym_key_up = mrb_intern_cstr(mrb, "key_up");
  sym_quit = mrb_intern_cstr(mrb, "quit");
  sym_tick = mrb_intern_cstr(mrb, "tick");

  fp = fopen(argv[2], "r");
  mrb_load_irep_file(mrb, fp);
  fclose(fp);
  if (mrb->exc) handle_error(mrb);

  mrb_funcall_id(mrb, main_obj, sym_init, 0);
  if (mrb->exc) handle_error(mrb);

  frame_start = SDL_GetTicks();

  // Game main loop.
  while(!cg_core.quit_game)
  {
    // Get input.
    while(SDL_PollEvent(&event) != 0)
    {
      switch(event.type)
      {
      case SDL_KEYDOWN:
	mrb_funcall_id(
	  mrb, main_obj, sym_key_down, 1,
	  mrb_int_value(mrb, event.key.keysym.sym));
	break;
      case SDL_KEYUP:
	mrb_funcall_id(
	  mrb, main_obj, sym_key_up, 1,
	  mrb_int_value(mrb, event.key.keysym.sym));
	break;
      case SDL_MOUSEMOTION:
	break;
      case SDL_MOUSEBUTTONDOWN:
	break;
      case SDL_MOUSEBUTTONUP:
	break;
      case SDL_QUIT:
	mrb_funcall_id(mrb, main_obj, sym_quit, 0);
	break;
      }
    }

    // Clear buffer.
    SDL_SetRenderDrawColor(cg_core.renderer, 0x00, 0x00, 0x00, 0xff);
    SDL_RenderClear(cg_core.renderer);

    mrb_funcall_id(mrb, main_obj, sym_tick, 0);
    if (mrb->exc) handle_error(mrb);

    // Copy buffer to the screen and display it.
    SDL_SetRenderTarget(cg_core.renderer, NULL);
    SDL_RenderCopy(
      cg_core.renderer, cg_core.pre_screen_buffer, NULL, &cg_core.screen_rect);
    SDL_RenderPresent(cg_core.renderer);
    SDL_SetRenderTarget(cg_core.renderer, cg_core.pre_screen_buffer);

    // Timer
    {
      Uint32 frame_stop, frame_duration;

      frame_stop = SDL_GetTicks();
      frame_duration = frame_stop - frame_start;

      // If frame take less time than maximum allowed.
      if(cg_core.max_frame_duration_ms > frame_duration)
	SDL_Delay(cg_core.max_frame_duration_ms - frame_duration);

      frame_start = frame_stop;
    }
  }

  mrb_close(mrb);
  cg_Core_unload(&core_loader);

  return 0;
}