/*
    Copyright (C) 2014 Fredrik Johansson

    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 "arf.h"

int
arf_cmp(const arf_t x, const arf_t y)
{
    int xs, ys, ec, mc;
    slong xn, yn;
    nn_srcptr xp, yp;

    if (arf_is_special(x) || arf_is_special(y))
    {
        if (arf_equal(x, y))
            return 0;
        if (arf_is_nan(x) || arf_is_nan(y))
            return 0;
        if (arf_is_zero(y)) return arf_sgn(x);
        if (arf_is_zero(x)) return -arf_sgn(y);
        if (arf_is_pos_inf(x)) return 1;
        if (arf_is_neg_inf(y)) return 1;
        return -1;
    }

    xs = ARF_SGNBIT(x);
    ys = ARF_SGNBIT(y);

    if (xs != ys)
        return xs ? -1 : 1;

    ec = fmpz_cmp(ARF_EXPREF(x), ARF_EXPREF(y));

    if (ec != 0)
        return ((ec < 0) ^ xs) ? -1 : 1;

    ARF_GET_MPN_READONLY(xp, xn, x);
    ARF_GET_MPN_READONLY(yp, yn, y);

    if (xn >= yn)
        mc = mpn_cmp(xp + xn - yn, yp, yn);
    else
        mc = mpn_cmp(xp, yp + yn - xn, xn);

    if (mc != 0)
        return ((mc < 0) ^ xs) ? -1 : 1;

    if (xn != yn)
        return ((xn < yn) ^ xs) ? -1 : 1;

    return 0;
}

int arf_cmp_si(const arf_t x, slong y)
{
    arf_t t;
    arf_init_set_si(t, y); /* no need to free */
    return arf_cmp(x, t);
}

int arf_cmp_ui(const arf_t x, ulong y)
{
    arf_t t;
    arf_init_set_ui(t, y); /* no need to free */
    return arf_cmp(x, t);
}

int arf_cmp_d(const arf_t x, double y)
{
    arf_t t;
    arf_init(t); /* no need to free */
    arf_set_d(t, y);
    return arf_cmp(x, t);
}

int
arf_cmpabs(const arf_t x, const arf_t y)
{
    int ec, mc;
    slong xn, yn;
    nn_srcptr xp, yp;

    if (arf_is_special(x) || arf_is_special(y))
    {
        if (arf_equal(x, y))
            return 0;
        if (arf_is_nan(x) || arf_is_nan(y))
            return 0;
        if (arf_is_zero(x)) return -1;
        if (arf_is_zero(y)) return 1;
        if (arf_is_inf(x)) return arf_is_inf(y) ? 0 : 1;
        if (arf_is_inf(y)) return -1;
        return -1;
    }

    ec = fmpz_cmp(ARF_EXPREF(x), ARF_EXPREF(y));

    if (ec != 0)
        return (ec < 0) ? -1 : 1;

    ARF_GET_MPN_READONLY(xp, xn, x);
    ARF_GET_MPN_READONLY(yp, yn, y);

    if (xn >= yn)
        mc = mpn_cmp(xp + xn - yn, yp, yn);
    else
        mc = mpn_cmp(xp, yp + yn - xn, xn);

    if (mc != 0)
        return (mc < 0) ? -1 : 1;

    if (xn != yn)
        return (xn < yn) ? -1 : 1;

    return 0;
}

int arf_cmpabs_ui(const arf_t x, ulong y)
{
    arf_t t;
    arf_init_set_ui(t, y); /* no need to free */
    return arf_cmpabs(x, t);
}

int arf_cmpabs_d(const arf_t x, double y)
{
    arf_t t;
    arf_init(t); /* no need to free */
    arf_set_d(t, y);
    return arf_cmpabs(x, t);
}

int
arf_cmp_2exp_si(const arf_t x, slong e)
{
    if (arf_is_special(x))
    {
        if (arf_is_zero(x)) return -1;
        if (arf_is_pos_inf(x)) return 1;
        if (arf_is_neg_inf(x)) return -1;
        return 0;
    }

    if (ARF_SGNBIT(x))
        return -1;

    /* Fast path. */
    if (!COEFF_IS_MPZ(ARF_EXP(x)))
    {
        if (ARF_IS_POW2(x) && (ARF_EXP(x) - 1 == e))
            return 0;
        else
            return (ARF_EXP(x) <= e) ? -1 : 1;
    }

    if (ARF_IS_POW2(x))
    {
        fmpz_t t;
        fmpz_init(t);
        fmpz_one(t);
        fmpz_add_si(t, t, e);
        if (fmpz_equal(ARF_EXPREF(x), t))
        {
            fmpz_clear(t);
            return 0;
        }
        fmpz_clear(t);
    }

    return (fmpz_cmp_si(ARF_EXPREF(x), e) <= 0) ? -1 : 1;
}

int
arf_cmpabs_2exp_si(const arf_t x, slong e)
{
    if (arf_is_special(x))
    {
        if (arf_is_zero(x)) return -1;
        if (arf_is_inf(x)) return 1;
        return 0;
    }

    /* Fast path. */
    if (!COEFF_IS_MPZ(ARF_EXP(x)))
    {
        if (ARF_IS_POW2(x) && (ARF_EXP(x) - 1 == e))
            return 0;
        else
            return (ARF_EXP(x) <= e) ? -1 : 1;
    }

    if (ARF_IS_POW2(x))
    {
        fmpz_t t;
        fmpz_init(t);

        fmpz_one(t);
        fmpz_add_si(t, t, e);

        if (fmpz_equal(ARF_EXPREF(x), t))
        {
            fmpz_clear(t);
            return 0;
        }

        fmpz_clear(t);
    }

    return (fmpz_cmp_si(ARF_EXPREF(x), e) <= 0) ? -1 : 1;
}
