from sympy.core.logic import (fuzzy_not, Logic, And, Or, Not, fuzzy_and,
    fuzzy_or, _fuzzy_group, _torf, fuzzy_nand, fuzzy_xor)
from sympy.testing.pytest import raises

from itertools import product

T = True
F = False
U = None



def test_torf():
    v = [T, F, U]
    for i in product(*[v]*3):
        assert _torf(i) is (True if all(j for j in i) else
                            (False if all(j is False for j in i) else None))


def test_fuzzy_group():
    v = [T, F, U]
    for i in product(*[v]*3):
        assert _fuzzy_group(i) is (None if None in i else
                                   (True if all(j for j in i) else False))
        assert _fuzzy_group(i, quick_exit=True) is \
            (None if (i.count(False) > 1) else
             (None if None in i else (True if all(j for j in i) else False)))
    it = (True if (i == 0) else None for i in range(2))
    assert _torf(it) is None
    it = (True if (i == 1) else None for i in range(2))
    assert _torf(it) is None


def test_fuzzy_not():
    assert fuzzy_not(T) == F
    assert fuzzy_not(F) == T
    assert fuzzy_not(U) == U


def test_fuzzy_and():
    assert fuzzy_and([T, T]) == T
    assert fuzzy_and([T, F]) == F
    assert fuzzy_and([T, U]) == U
    assert fuzzy_and([F, F]) == F
    assert fuzzy_and([F, U]) == F
    assert fuzzy_and([U, U]) == U
    assert [fuzzy_and([w]) for w in [U, T, F]] == [U, T, F]
    assert fuzzy_and([T, F, U]) == F
    assert fuzzy_and([]) == T
    raises(TypeError, lambda: fuzzy_and())


def test_fuzzy_or():
    assert fuzzy_or([T, T]) == T
    assert fuzzy_or([T, F]) == T
    assert fuzzy_or([T, U]) == T
    assert fuzzy_or([F, F]) == F
    assert fuzzy_or([F, U]) == U
    assert fuzzy_or([U, U]) == U
    assert [fuzzy_or([w]) for w in [U, T, F]] == [U, T, F]
    assert fuzzy_or([T, F, U]) == T
    assert fuzzy_or([]) == F
    raises(TypeError, lambda: fuzzy_or())


def test_logic_onearg():
    assert And() is True
    assert Or() is False

    assert And(T) == T
    assert And(F) == F
    assert Or(T) == T
    assert Or(F) == F

    assert And('a') == 'a'
    assert Or('a') == 'a'


def test_logic_xnotx():
    assert And('a', Not('a')) == F
    assert Or('a', Not('a')) == T


def test_logic_eval_TF():
    assert And(F, F) == F
    assert And(F, T) == F
    assert And(T, F) == F
    assert And(T, T) == T

    assert Or(F, F) == F
    assert Or(F, T) == T
    assert Or(T, F) == T
    assert Or(T, T) == T

    assert And('a', T) == 'a'
    assert And('a', F) == F
    assert Or('a', T) == T
    assert Or('a', F) == 'a'


def test_logic_combine_args():
    assert And('a', 'b', 'a') == And('a', 'b')
    assert Or('a', 'b', 'a') == Or('a', 'b')

    assert And(And('a', 'b'), And('c', 'd')) == And('a', 'b', 'c', 'd')
    assert Or(Or('a', 'b'), Or('c', 'd')) == Or('a', 'b', 'c', 'd')

    assert Or('t', And('n', 'p', 'r'), And('n', 'r'), And('n', 'p', 'r'), 't',
              And('n', 'r')) == Or('t', And('n', 'p', 'r'), And('n', 'r'))


def test_logic_expand():
    t = And(Or('a', 'b'), 'c')
    assert t.expand() == Or(And('a', 'c'), And('b', 'c'))

    t = And(Or('a', Not('b')), 'b')
    assert t.expand() == And('a', 'b')

    t = And(Or('a', 'b'), Or('c', 'd'))
    assert t.expand() == \
        Or(And('a', 'c'), And('a', 'd'), And('b', 'c'), And('b', 'd'))


def test_logic_fromstring():
    S = Logic.fromstring

    assert S('a') == 'a'
    assert S('!a') == Not('a')
    assert S('a & b') == And('a', 'b')
    assert S('a | b') == Or('a', 'b')
    assert S('a | b & c') == And(Or('a', 'b'), 'c')
    assert S('a & b | c') == Or(And('a', 'b'), 'c')
    assert S('a & b & c') == And('a', 'b', 'c')
    assert S('a | b | c') == Or('a', 'b', 'c')

    raises(ValueError, lambda: S('| a'))
    raises(ValueError, lambda: S('& a'))
    raises(ValueError, lambda: S('a | | b'))
    raises(ValueError, lambda: S('a | & b'))
    raises(ValueError, lambda: S('a & & b'))
    raises(ValueError, lambda: S('a |'))
    raises(ValueError, lambda: S('a|b'))
    raises(ValueError, lambda: S('!'))
    raises(ValueError, lambda: S('! a'))
    raises(ValueError, lambda: S('!(a + 1)'))
    raises(ValueError, lambda: S(''))


def test_logic_not():
    assert Not('a') != '!a'
    assert Not('!a') != 'a'
    assert Not(True) == False
    assert Not(False) == True

    # NOTE: we may want to change default Not behaviour and put this
    # functionality into some method.
    assert Not(And('a', 'b')) == Or(Not('a'), Not('b'))
    assert Not(Or('a', 'b')) == And(Not('a'), Not('b'))

    raises(ValueError, lambda: Not(1))


def test_formatting():
    S = Logic.fromstring
    raises(ValueError, lambda: S('a&b'))
    raises(ValueError, lambda: S('a|b'))
    raises(ValueError, lambda: S('! a'))


def test_fuzzy_xor():
    assert fuzzy_xor((None,)) is None
    assert fuzzy_xor((None, True)) is None
    assert fuzzy_xor((None, False)) is None
    assert fuzzy_xor((True, False)) is True
    assert fuzzy_xor((True, True)) is False
    assert fuzzy_xor((True, True, False)) is False
    assert fuzzy_xor((True, True, False, True)) is True

def test_fuzzy_nand():
    for args in [(1, 0), (1, 1), (0, 0)]:
        assert fuzzy_nand(args) == fuzzy_not(fuzzy_and(args))
