/*
    Copyright (C) 2009 William Hart

    This file is part of FLINT.

    FLINT is free software: you can redistribute it and/or modify it under
    the terms of the GNU Lesser General Public License (LGPL) as published
    by the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.  See <https://www.gnu.org/licenses/>.
*/

#include "test_helpers.h"
#include "gmpcompat.h"
#include "ulong_extras.h"

TEST_FUNCTION_START(n_is_probabprime_fermat, state)
{
    int i, result;
    ulong count = UWORD(0);
    ulong d, j;
    mpz_t d_m;

    for (i = 0; i < 10000 * flint_test_multiplier(); i++) /* Test that primes pass the test */
    {
        mpz_init(d_m);

        do
        {
            d = n_randtest_not_zero(state);
            if (d == UWORD(1)) d++;
            flint_mpz_set_ui(d_m, d);
            mpz_nextprime(d_m, d_m);
            d = flint_mpz_get_ui(d_m);
        } while (mpz_size(d_m) > 1);

        do
        {
            j = n_randtest(state) % d;
            if ((j == WORD(1)) && (d != UWORD(2))) j++;
        } while (n_gcd(d, j) != UWORD(1));

        result = n_is_probabprime_fermat(d, j);
        if (!result)
            TEST_FUNCTION_FAIL("d = %wu is declared composite\n", d);

        mpz_clear(d_m);
    }

    for (i = 0; i < 10000 * flint_test_multiplier(); i++) /* Test that not too many composites pass */
    {
        mpz_init(d_m);

        do
        {
            d = n_randtest_bits(state, n_randint(state, FLINT_BITS) + 1);
            if (d < UWORD(2)) d = 2;
            flint_mpz_set_ui(d_m, d);
        } while (mpz_probab_prime_p(d_m, 12));

        do
        {
            j = n_randtest(state) % d;
            if ((j == WORD(1)) && (d != UWORD(2))) j++;
        } while (n_gcd(d, j) != UWORD(1));

        if (n_is_probabprime_fermat(d, j)) count++;

        mpz_clear(d_m);
    }

    result = (count < 200 * flint_test_multiplier());
    if (!result)
        TEST_FUNCTION_FAIL("%wu composites declared prime\n", count);

    TEST_FUNCTION_END(state);
}
