#include "TZR_render.h"
#include "TZR_globals.h"
#include "TZR_resource.h"
#include "sdl_error.h"
#include <SDL2/SDL_render.h>
#include <SDL2/SDL_timer.h>

static int
pixel_draw_end(void)
{
	if (___tzr_config.interlace) {
		static int odd = 0;
		odd ^= 1;
		for (int i = odd; i < ___tzr_config.height; i += 2) {
			const SDL_Rect rect = {
				0,
				i,
				___tzr_config.width,
				1
			};
			if (SDL_RenderCopy(___tzr_renderer,
			                   ___tzr_target_pre,
			                   &rect,
			                   &rect) < 0)
				return sdl_error(-1);
		}
	}

	if (SDL_SetRenderTarget(___tzr_renderer, NULL) < 0)
		return sdl_error(-1);
	if (SDL_SetRenderDrawColor(___tzr_renderer, 0, 0, 0, 255) < 0)
		return sdl_error(-1);
	if (SDL_RenderClear(___tzr_renderer) < 0)
		return sdl_error(-1);

	int win_w, win_h;
	SDL_GetWindowSize(___tzr_window, &win_w, &win_h);
	win_w = win_w ? win_w : 1;
	win_h = win_h ? win_h : 1;

	const int width = ___tzr_config.width * ___tzr_config.ratio;
	const float ratio_w = win_w / (float)(width);
	const float ratio_h = win_h / (float)___tzr_config.height;
	___tzr_scale = (ratio_w < ratio_h) ? ratio_w : ratio_h;
	if (___tzr_scale > 1.0f && ___tzr_config.pixel_perfect)
		___tzr_scale = (int)___tzr_scale;
	___tzr_off_x = (win_w - width * ___tzr_scale) / 2;
	___tzr_off_y = (win_h - ___tzr_config.height * ___tzr_scale) / 2;
	const SDL_Rect dest = {
		___tzr_off_x,
		___tzr_off_y,
		width * ___tzr_scale,
		___tzr_config.height * ___tzr_scale
	};

	if (SDL_RenderCopy(___tzr_renderer, ___tzr_target, NULL, &dest) < 0)
		return sdl_error(-1);

	return 0;
}

int
TZR_DrawEnd(void)
{
	if (!___tzr_config.hd_render && pixel_draw_end())
		return -1;

	if (___tzr_config.target_fps > 0) {
		___tzr_next_time += ___tzr_min_dt;
		if (___tzr_config.target_fps == 60 && ___tzr_tick % 3 < 2)
			___tzr_next_time += 1;
		const unsigned long cur_time = SDL_GetTicks64();
		if (___tzr_next_time <= cur_time)
			___tzr_next_time = cur_time;
		else
			SDL_Delay(___tzr_next_time - cur_time);
	}
	SDL_RenderPresent(___tzr_renderer);

	___tzr_tick += 1;
	return 0;
}