#ifndef LZY_H_
#define LZY_H_
#ifdef __cplusplus
extern "C" {
#endif
#include <stdint.h>

#define LZY_UNUSED(x) (void)(x)

int LZY_Init(const char *title, int target_fps);
void LZY_Quit(void);
int LZY_DrawBegin(void);
int LZY_DrawEnd(void);
void LZY_DrawSetColor(uint8_t r, uint8_t g, uint8_t b);
void LZY_DrawSetColorNone(void);
int LZY_DrawClear(void);
void LZY_CycleEvents(void);
int LZY_KeyDown(unsigned int key);
int LZY_ShouldQuit(void);
void LZY_Log(const char *msg);
const char *LZY_GetError(void);

#ifdef FXCG50
#include <gint/keycodes.h>
enum LZY_ScanCode {
	LZYK_LEFT = KEY_LEFT,
	LZYK_RIGHT = KEY_RIGHT,
	LZYK_UP = KEY_UP,
	LZYK_DOWN = KEY_DOWN,
};
#else /* end FXCG50, begin SDL2 */
#include <SDL.h>
enum LZY_ScanCode {
	LZYK_LEFT,
	LZYK_RIGHT,
	LZYK_UP,
	LZYK_DOWN,
	LZYK_COUNT,
};
#endif /* SDL2 */
#ifdef __cplusplus
}
#endif
#endif /* LZY_H_ */

/* implementation */
#ifdef LZY_IMPLEMENTATION
#ifndef LZY_TILE_SIZE
#define LZY_TILE_SIZE 16
#endif
#ifndef LZY_DISPLAY_WIDTH
#define LZY_DISPLAY_WIDTH 400
#endif
#ifndef LZY_DISPLAY_HEIGHT
#define LZY_DISPLAY_HEIGHT 224
#endif

#ifdef FXCG50
#include <gint/cpu.h>
#include <gint/display.h>
#include <gint/keyboard.h>
#include <gint/timer.h>
#include <stdint.h>

static color_t draw_color = C_BLACK;
static int should_quit = 0;
static int timer = 0;
static volatile int has_ticked = 0;

static int timer_callback(volatile int *);

int LZY_Init(const char *title, int target_fps) {
	LZY_UNUSED(title);
	if (target_fps > 0) {
		timer = timer_configure(TIMER_ANY, 1000000 / target_fps,
		                        GINT_CALL(timer_callback, &has_ticked));
		timer_start(timer);
	}
	return 0;
}

static int timer_callback(volatile int *arg) {
	*arg += 1;
	return 0;
}

void LZY_Quit(void) {
	if (timer) {
		timer_stop(timer);
		timer = 0;
	}
}

int LZY_DrawBegin(void) {
	return 0;
}

int LZY_DrawEnd(void) {
	dupdate();
	while (timer && !has_ticked)
		sleep();
	has_ticked = 0;
	return 0;
}

void LZY_DrawSetColor(uint8_t r, uint8_t g, uint8_t b) {
	draw_color = C_RGB(r / 8, g / 8, b / 8);
}

void LZY_DrawSetColorNone(void) {
	draw_color = C_NONE;
}

int LZY_DrawClear(void) {
	dclear(draw_color);
	return 0;
}

void LZY_CycleEvents(void) {
	clearevents();
	should_quit = should_quit || keydown(KEY_EXIT);
}

int LZY_KeyDown(unsigned int key) {
	return keydown(key);
}

int LZY_ShouldQuit(void) {
	return should_quit;
}

void LZY_Log(const char *msg) {
	LZY_UNUSED(msg);
}

const char *LZY_GetError(void) {
	return NULL;
}

#else /* end FXCG50, begin SDL2 */
#include <SDL.h>
#include <stdint.h>

static const char *error = NULL;
static SDL_Window *window = NULL;
static SDL_Renderer *renderer = NULL;
static int should_quit = 0;
static int input[LZYK_COUNT] = {0};
static int fps_limiter = 0;
static uint64_t min_dt;
static uint64_t next_time;

int LZY_Init(const char *title, int target_fps) {
	if (SDL_Init(SDL_INIT_VIDEO) < 0) {
		error = SDL_GetError();
		return 1;
	}

	SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, 0);

	window = SDL_CreateWindow(title, SDL_WINDOWPOS_UNDEFINED,
	                          SDL_WINDOWPOS_UNDEFINED, LZY_DISPLAY_WIDTH,
	                          LZY_DISPLAY_HEIGHT, SDL_WINDOW_SHOWN);
	if (window == NULL) {
		error = SDL_GetError();
		return 2;
	}

	SDL_SetWindowMinimumSize(window, LZY_DISPLAY_WIDTH, LZY_DISPLAY_HEIGHT);

	renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
	if (renderer == NULL) {
		error = SDL_GetError();
		return 3;
	}

	fps_limiter = target_fps > 0;
	if (fps_limiter) {
		min_dt = 1000 / target_fps;
		next_time = SDL_GetTicks64();
	}

	return 0;
}

void LZY_Quit(void) {
	if (renderer != NULL) {
		SDL_DestroyRenderer(renderer);
		renderer = NULL;
	}

	if (window != NULL) {
		SDL_DestroyWindow(window);
		window = NULL;
	}

	SDL_Quit();
}

int LZY_DrawBegin(void) {
	if (fps_limiter)
		next_time += min_dt;
	return 0;
}

int LZY_DrawEnd(void) {
	SDL_RenderPresent(renderer);

	if (fps_limiter) {
		const uint64_t cur_time = SDL_GetTicks64();
		if (next_time <= cur_time)
			next_time = cur_time;
		else
			SDL_Delay(next_time - cur_time);
	}
	return 0;
}

void LZY_DrawSetColor(uint8_t r, uint8_t g, uint8_t b) {
	SDL_SetRenderDrawColor(renderer, r, g, b, 0xff);
}

void LZY_DrawSetColorNone(void) {
	SDL_SetRenderDrawColor(renderer, 0x00, 0x00, 0x00, 0x00);
}

int LZY_DrawClear(void) {
	if (SDL_RenderClear(renderer) < 0) {
		error = SDL_GetError();
		return 1;
	}
	return 0;
}

void LZY_CycleEvents(void) {
	static const SDL_Scancode sc[LZYK_COUNT] = {
	    SDL_SCANCODE_LEFT,
	    SDL_SCANCODE_RIGHT,
	    SDL_SCANCODE_UP,
	    SDL_SCANCODE_DOWN,
	};
	SDL_Event e;

	while (SDL_PollEvent(&e) != 0) {
		switch (e.type) {
		case SDL_QUIT:
			should_quit = 1;
			break;
		case SDL_KEYDOWN: {
			int i = LZYK_COUNT;
			while (i-- > 0) {
				if (sc[i] == e.key.keysym.scancode) {
					input[i] = 1;
					break;
				}
			}
		} break;
		case SDL_KEYUP: {
			int i = LZYK_COUNT;
			while (i-- > 0) {
				if (sc[i] == e.key.keysym.scancode) {
					input[i] = 0;
					break;
				}
			}
		} break;
		default:
			break;
		}
	}
}

int LZY_KeyDown(unsigned int key) {
	if (key >= LZYK_COUNT)
		return 0;
	return input[key];
}

int LZY_ShouldQuit(void) {
	return should_quit;
}

void LZY_Log(const char *msg) {
	SDL_Log(msg);
}

const char *LZY_GetError(void) {
	return error;
}
#endif /* SDL2 */
#endif /* LZY_IMPLEMENTATION */