#include "rsa.h"

int64_t euler(int64_t r0, int64_t r1) {
	int64_t s0 = 1;
	int64_t s1 = 0;
	int64_t t0 = 0;
	int64_t t1 = 1;
	int64_t q0 = 0;

	while (r1 != 0) {
		q0 = r0 / r1;
		int64_t tmp = r0 % r1;
		r0 = r1;
		r1 = tmp;
		tmp = s0 - q0 * s1;
		s0 = s1;
		s1 = tmp;
		tmp = t0 - q0 * t1;
		t0 = t1;
		t1 = tmp;
	}
	return s0;
}

rsa_t rsa_generate_keys(void) {
	for (int try = 0; try < 1000; try++) {

	if (try % 100 == 0)
		printf("try: %d\n", try);
	int64_t p = (uint64_t)generate_prime();
	int64_t q = (uint64_t)generate_prime();
	int64_t ln = (p - 1) * (q - 1);
	int64_t e = 11317;

	while (ln % e == 0 || p == q) {
		p = generate_prime();
		q = generate_prime();
		ln = (p - 1) * (q - 1);
	}

	if (q > p) {
		uint64_t tmp = p;
		p = q;
		q = tmp;
	}
	int64_t n = p * q;

	int64_t r0 = e;
	int64_t r1 = ln;
	int64_t s0 = 1;
	int64_t s1 = 0;
	int64_t t0 = 0;
	int64_t t1 = 1;
	int64_t q0 = 0;

	while (r1 != 0) {
		q0 = r0 / r1;
		int64_t tmp = r0 % r1;
		r0 = r1;
		r1 = tmp;
		tmp = s0 - q0 * s1;
		s0 = s1;
		s1 = tmp;
		tmp = t0 - q0 * t1;
		t0 = t1;
		t1 = tmp;
	}

	int64_t d = euler(e, ln) + ln;
	if (d > n) {
		d -= ln;
	}

/*	printf("p: %ld\n", p);
	printf("q: %ld\n", q);
	printf("ln: %ld\n", ln);
	printf("n: %ld\n", n);
	printf("d: %ld\n", d);
	printf("e: %ld\n", e);
	printf("d * e %% ln = %ld\n", (d*e)%ln);*/
	for (uint64_t m = 0; m < 16384; m++) {
		//uint64_t m = get_random_bytes(fd2);
		uint64_t c = pow_mod(m, e, n);
		uint64_t m2 = pow_mod(c, d, n);
		if (m != m2) {
			printf("ERROR try: %d\nround: n/a\nmsg: %ld\ncypher: %ld\ndecrypted: %ld\nd: %ld\ne: %ld\np: %lu\nq: %lu\nn: %lu\n", try, m, c, m2, d, e, p, q, n);
			break;
		}
	}
	//int64_t m = 42;
	/*
	for (int64_t m = 41; m < 43; m++) {
	int64_t c = pow_mod(m, e, n);
	int64_t m2 = pow_mod(c, d, n);
	if (d < 0) {
		int64_t c2 = euler(c, n);
		printf("c2: %ld\n", c2);
		printf("c2 * c %% n = %ld\n", ((c2 + n)*c)%n);
		printf("c2 * c %% n = %ld\n", ((c2)*c)%n);
		m2 = pow_mod(c2 + n, -d, n);
	}
	printf("message: %ld\n", m);
	printf("cypher: %ld\n", c);
	printf("decrypted: %ld\n", m2);
	}*/
	}
	rsa_t rsa;
	rsa.p.len = 42;
	return rsa;
}