#include <stdlib.h>
#include <stdbool.h>
#include <stdio.h>

#include <allegro5/allegro5.h>
#include <allegro5/allegro_primitives.h>

#include <sodium.h>

#define DO_INIT(check, desc) \
	if (!(check)) { \
		fprintf(stderr, "err: can't initialise %s\n", desc); \
		rval = 1; \
		goto done; \
	}

int main(int argc, char **argv)
{
	int rval = 0;
	unsigned goframes;
	uint32_t randbytes;

	struct {
		uint32_t middle;
		uint32_t upper;
		uint32_t lower;
	} biases[4] = {
		/* unbiased */
		{
			.middle = 0x80000000,
			.upper = 0xc0000000,
			.lower = 0x40000000,
		},
		/* 1/64 */
		{
			.middle = 0x7c000000,
			.upper = 0xbe000000,
			.lower = 0x3e000000,
		},
		/* 1/32 */
		{
			.middle = 0x78000000,
			.upper = 0xbc000000,
			.lower = 0x3c000000,
		},
		/* 1/16 */
		{
			.middle = 0x70000000,
			.upper = 0xb8000000,
			.lower = 0x38000000,
		}
	};
	unsigned setting = 0;

	ALLEGRO_DISPLAY* d = NULL;
	ALLEGRO_TIMER* t = NULL;
	ALLEGRO_EVENT_QUEUE* eq = NULL;
	ALLEGRO_EVENT e;

	float x = 320.0, y = 240.0;


	DO_INIT(sodium_init() >= 0, "sodium");

	DO_INIT(al_init(), "allegro");
	DO_INIT(al_init_primitives_addon(), "primitives");
	DO_INIT(al_install_keyboard(), "keyboard");

	DO_INIT(t = al_create_timer(1.0 / 60.0), "timer");
	DO_INIT(eq = al_create_event_queue(), "event queue");

	al_set_new_display_option(ALLEGRO_SINGLE_BUFFER, 1, ALLEGRO_REQUIRE);
	DO_INIT(d = al_create_display(641, 481), "display");

	al_register_event_source(eq, al_get_keyboard_event_source());
	al_register_event_source(eq, al_get_display_event_source(d));
	al_register_event_source(eq, al_get_timer_event_source(t));

	al_clear_to_color(al_map_rgb(0, 0, 0));


	goframes = 0;
	al_start_timer(t);
	while(true) {
		al_wait_for_event(eq, &e);

		switch (e.type) {

		case ALLEGRO_EVENT_DISPLAY_CLOSE:
			goto done;

		case ALLEGRO_EVENT_KEY_DOWN:
			switch(e.keyboard.keycode) {

			case ALLEGRO_KEY_1:
				setting = 0;
				puts("1");
				break;

			case ALLEGRO_KEY_2:
				setting = 1;
				puts("2");
				break;

			case ALLEGRO_KEY_3:
				setting = 2;
				puts("3");
				break;

			case ALLEGRO_KEY_4:
				setting = 3;
				puts("4");
				break;

			default:
				break;

			}

			if (! (e.keyboard.keycode == ALLEGRO_KEY_ENTER) )
				continue;

			goframes = 1000;
		case ALLEGRO_EVENT_TIMER:
			if (goframes == 0) {
				al_flip_display();
				break;
			}

			al_put_pixel(x, y, al_map_rgb(255, 255, 255));

			randbytes = randombytes_random();

			if (randbytes >= biases[setting].middle) {
				if (randbytes >= biases[setting].upper)
					x += 1;
				else
					y += 1;
			} else {
				if (randbytes >= biases[setting].lower)
					x -= 1;
				else
					y -= 1;
			}

			al_flip_display();

			goframes--;
			if (goframes == 0)
				puts("next");
		}
	}


done:

	if (d)
		al_destroy_display(d);
	if (t)
		al_destroy_timer(t);
	if (eq)
		al_destroy_event_queue(eq);
	
	return rval;
}