/*
 * Copyright ©️ 2024 Mario Forzanini <mf@marioforzanini.com>
 *
 * This file is part of my exercises for LSN.
 *
 * My exercises for LSN are free software: you can redistribute them
 * and/or modify them under the terms of the GNU General Public License
 * as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * My exercises for LSN are distributed in the hope that they will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with my exercises for LSN. If not, see
 * <https://www.gnu.org/licenses/>.
 *
 */

#include <errno.h>
#include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>

#include "random.h"
#include "std.h"

#define M 100
#define NTHROWS 10000
#define PROBABILITY ((double)(NTHROWS) / (double)(M))

/*! Array where progressive values of χ2 are stored */
static double bins[M] = { 0 };

int
main(void)
{
	FILE *primes, *input;
	Random rnd = { 0 };
	if (!(primes = fopen("Primes", "r"))) {
		STD_ERROR("Error opening Primes: %s\n", strerror(errno));
		return 1;
	} else if (!(input = fopen("seed.in", "r"))) {
		STD_ERROR("Error opening seed.in: %s\n", strerror(errno));
		return 1;
	}
	if (!random_init(&rnd, primes, input)) {
		return 1;
	}
	for (int j = 0; j < 100; j++) {
		double chi2 = 0.0;
		for (int i = 0; i < NTHROWS; i++) {
			double random = random_rannyu(&rnd);
			bins[(int)(floor(random * M))]++;
		}
		for (int bin = 0; bin < M; bin++) {
			chi2 += pow(bins[bin] - PROBABILITY, 2);
		}
		printf("%d %lf\n", j, chi2 / PROBABILITY);
		memset(bins, 0, LEN(bins) * sizeof(*bins));
	}
	random_save_seed(&rnd, "seed.out");
	return 0;
}