# This program is free software: you can redistribute it and/or modify
# it 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.
#
# This program is distributed in the hope that it 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 this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Copyright(C) 2020 Max-Planck-Society
#
# NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.

import numpy as np

import nifty8 as ift


def check_state_back_to_orig():
    np.testing.assert_equal(len(ift.random._rng),1)
    np.testing.assert_equal(len(ift.random._sseq),1)


def test_rand1():
    with ift.random.Context(31):
        a = ift.random.current_rng().integers(0,1000000000)
    with ift.random.Context(31):
        b = ift.random.current_rng().integers(0,1000000000)
    check_state_back_to_orig()
    np.testing.assert_equal(a,b)


def test_rand2():
    sseq = ift.random.spawn_sseq(10)
    with ift.random.Context(sseq[2]):
        a = ift.random.current_rng().integers(0,1000000000)
    with ift.random.Context(sseq[2]):
        b = ift.random.current_rng().integers(0,1000000000)
    check_state_back_to_orig()
    np.testing.assert_equal(a,b)


def test_rand3():
    with ift.random.Context(31):
        sseq = ift.random.spawn_sseq(10)
        with ift.random.Context(sseq[2]):
            a = ift.random.current_rng().integers(0,1000000000)
    with ift.random.Context(31):
        sseq = ift.random.spawn_sseq(1)
        sseq = ift.random.spawn_sseq(1)
        sseq = ift.random.spawn_sseq(1)
        with ift.random.Context(sseq[0]):
            b = ift.random.current_rng().integers(0,1000000000)
    check_state_back_to_orig()
    np.testing.assert_equal(a,b)


def test_rand4():
    with ift.random.Context(31):
        a = ift.random.current_rng().integers(0,1000000000)
        with ift.random.Context(31):
            b = ift.random.current_rng().integers(0,1000000000)
    np.testing.assert_equal(a,b)


def test_rand5():
    ift.random.push_sseq_from_seed(31)
    a = ift.random.current_rng().integers(0,1000000000)
    ift.random.push_sseq_from_seed(31)
    b = ift.random.current_rng().integers(0,1000000000)
    c = ift.random.current_rng().integers(0,1000000000)
    ift.random.pop_sseq()
    d = ift.random.current_rng().integers(0,1000000000)
    ift.random.pop_sseq()
    check_state_back_to_orig()
    np.testing.assert_equal(a,b)
    np.testing.assert_equal(c,d)


def test_rand5b():
    with ift.random.Context(31):
        a = ift.random.current_rng().integers(0,1000000000)
        with ift.random.Context(31):
            b = ift.random.current_rng().integers(0,1000000000)
            c = ift.random.current_rng().integers(0,1000000000)
        d = ift.random.current_rng().integers(0,1000000000)
    check_state_back_to_orig()
    np.testing.assert_equal(a,b)
    np.testing.assert_equal(c,d)


def test_rand6():
    ift.random.push_sseq_from_seed(31)
    state = ift.random.getState()
    a = ift.random.current_rng().integers(0,1000000000)
    ift.random.setState(state)
    b = ift.random.current_rng().integers(0,1000000000)
    np.testing.assert_equal(a,b)
    ift.random.pop_sseq()
    check_state_back_to_orig()


def test_rand6b():
    with ift.random.Context(31):
        state = ift.random.getState()
        a = ift.random.current_rng().integers(0,1000000000)
        ift.random.setState(state)
        b = ift.random.current_rng().integers(0,1000000000)
        np.testing.assert_equal(a,b)
    check_state_back_to_orig()