#include <math.h>
#include <ncurses.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define HORIZONTAL_STDEV 50
#define VERTICAL_STDEV 50

// board spec from WDF rules
#define WIRE_WIDTH 1.56
#define INNER_DIAMETER_BULL 12.7
#define INNER_DIAMETER_25 31.8
#define DOUBLE_OUTER_EDGE 170.0
#define TREBLE_OUTER_EDGE 107.4
#define DOUBLE_INSIDE_WIDTH 8.0
#define TREBLE_INSIDE_WIDTH 8.0

#define SEGMENT_MAX_LEN 5
// distance from centre to apex of outer wire
// must be ordered outwards from centre
#define FOREACH_RING(M) \
	M(BULL, INNER_DIAMETER_BULL/2 + WIRE_WIDTH/2) \
	M(25, INNER_DIAMETER_25/2 + WIRE_WIDTH/2) \
	M(SMALL, TREBLE_OUTER_EDGE - WIRE_WIDTH - TREBLE_INSIDE_WIDTH - \
		WIRE_WIDTH/2) \
	M(TREBLE, TREBLE_OUTER_EDGE - WIRE_WIDTH/2) \
	M(BIG, DOUBLE_OUTER_EDGE - WIRE_WIDTH - DOUBLE_INSIDE_WIDTH - \
		WIRE_WIDTH/2) \
	M(DOUBLE, DOUBLE_OUTER_EDGE - WIRE_WIDTH/2)
#define GEN_RING_ENUM(X, D) R_ ## X,
#define GEN_RING_STRING(X, D) #X,
#define GEN_RING_OUTER_DIST(X, D) D,

int sectors[] = { 20, 1, 18, 4, 13, 6, 10, 15, 2, 17, 3, 19, 7,
	16, 8, 11, 14, 9, 12, 5 };

enum ring {
	FOREACH_RING(GEN_RING_ENUM)
	R_OUT
};

char *RING_NAMES[] = {
	FOREACH_RING(GEN_RING_STRING)
	"OUT"
};

double OUTER_DISTS[] = {
	FOREACH_RING(GEN_RING_OUTER_DIST)
};

double CENTRE_DISTS[sizeof(OUTER_DISTS)/sizeof(*OUTER_DISTS)];
void init_centre_dists()
{
	CENTRE_DISTS[0] = 0;
	for (int i = R_25; i < R_OUT; ++i)
		CENTRE_DISTS[i] = (OUTER_DISTS[i] -
			((OUTER_DISTS[i] - OUTER_DISTS[i-1]) / 2));
}

struct ccoords {
	double x, y;
};

struct pcoords {
	double a, r;
};

struct segment {
	enum ring ring;
	int sector;
};

int get_sector(double angle)
{
	//return sectors[(int)(fmod(angle + 279, 360) / 18)];
	double shifted = angle + 279;
	return sectors[(int)((shifted - (360 * floor(shifted / 360))) / 18)];
}

enum ring get_ring(double radius)
{
	for (int i = R_BULL; i < R_OUT; ++i)
		if (radius < OUTER_DISTS[i])
			return i;

	return R_OUT;
}

double drand()
{
	return (double)rand() / RAND_MAX;
}

double gauss(double mean, double stdev)
{
	static bool have_next;
	static double next;

	double curr;

	if (have_next) {
		curr = next;
	} else {
		double theta = 2 * M_PI * drand();
		double r = sqrt(-2 * log(1 - drand()));

		curr = r * cos(theta);
		next = r * sin(theta);
	}

	have_next = !have_next;
	return mean + (curr * stdev);
}

struct ccoords get_offset()
{
	return (struct ccoords){ .x = gauss(0, HORIZONTAL_STDEV),
		.y = gauss(0, VERTICAL_STDEV) };
}

struct ccoords pol_to_cart(struct pcoords c)
{
	double t = c.a * (M_PI / 180);
	double x = c.r * cos(t);
	double y = c.r * sin(t);

	return (struct ccoords){ .x = x, .y = y };
}

struct pcoords cart_to_pol(struct ccoords c)
{
	double a = atan2(c.y, c.x) * (180 / M_PI);
	double r = sqrt(pow(c.x, 2) + pow(c.y, 2));

	return (struct pcoords){ .a = a, .r = r };
}

struct pcoords throw_dart(struct pcoords target)
{
	struct ccoords cc = pol_to_cart(target);
	struct ccoords offset = get_offset();

	return cart_to_pol((struct ccoords){ .x = cc.x + offset.x,
		.y = cc.y + offset.y });
}

struct segment get_segment(struct pcoords c)
{
	return (struct segment){ .sector = get_sector(c.a),
		.ring = get_ring(c.r) };
}

char *segment_name(struct segment seg)
{
	char *str = malloc(SEGMENT_MAX_LEN);

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstringop-truncation"
	if (seg.ring == R_BULL || seg.ring == R_25 || seg.ring == R_OUT)
		strncpy(str, RING_NAMES[seg.ring], SEGMENT_MAX_LEN);
	else
		snprintf(str, SEGMENT_MAX_LEN,
			(seg.ring == R_TREBLE ? "T%d" :
				(seg.ring == R_DOUBLE ? "D%d" : "%d")),
			seg.sector);
#pragma GCC diagnostic pop

	return str;
}

int main()
{
	/*
	initscr();
	addstr("test");
	refresh();

	getch();
	endwin();
	*/
	srand(time(NULL));
	init_centre_dists();

	struct pcoords t = { .a = 90, .r = 100 };
	struct pcoords res = throw_dart(t);
	struct segment seg = get_segment(res);

	for (int i = 0; i < 20; ++i) {
		res = throw_dart(t);
		seg = get_segment(res);
		char *name = segment_name(seg);
		printf("%d %f %f %d %s %s\n", seg.sector, res.a, res.r, seg.ring,
			RING_NAMES[seg.ring], name);
		free(name);
	}

	/*
	printf("\n");
	for (int i = 0; i < 6; i++) {
		printf("%.2f\n%.2f\n\n", CENTRE_DISTS[i], OUTER_DISTS[i]);
	}
	*/

	return 0;
}