import functools
import unittest

from ..linexprs import symbols
from ..polyhedra import *


try:
    import sympy
    def _requires_sympy(func):
        @functools.wraps(func)
        def wrapper(self):
            return func(self)
        return wrapper
except ImportError:
    def _requires_sympy(func):
        @functools.wraps(func)
        def wrapper(self):
            raise unittest.SkipTest('SymPy is not available')
        return wrapper


class TestPolyhedron(unittest.TestCase):

    def setUp(self):
        x, y = symbols('x y')
        self.square = Polyhedron(inequalities=[x, 1 - x, y, 1 - y])

    def test_symbols(self):
        self.assertCountEqual(self.square.symbols, ['x', 'y'])

    def test_dimension(self):
        self.assertEqual(self.square.dimension, 2)

    def test_str(self):
        self.assertEqual(str(self.square),
            'And(Ge(x, 0), Ge(-x + 1, 0), Ge(y, 0), Ge(-y + 1, 0))')

    def test_repr(self):
        self.assertEqual(repr(self.square),
            "And(Ge(x, 0), Ge(-x + 1, 0), Ge(y, 0), Ge(-y + 1, 0))")

    def test_fromstring(self):
        self.assertEqual(Polyhedron.fromstring('{x >= 0, -x + 1 >= 0, '
            'y >= 0, -y + 1 >= 0}'), self.square)

    def test_isempty(self):
        self.assertFalse(self.square.isempty())

    def test_isuniverse(self):
        self.assertFalse(self.square.isuniverse())

    @_requires_sympy
    def test_fromsympy(self):
        sp_x, sp_y = sympy.symbols('x y')
        self.assertEqual(Polyhedron.fromsympy((sp_x >= 0) & (sp_x <= 1) &
            (sp_y >= 0) & (sp_y <= 1)), self.square)

    @_requires_sympy
    def test_tosympy(self):
        sp_x, sp_y = sympy.symbols('x y')
        self.assertEqual(self.square.tosympy(),
            sympy.And(-sp_x + 1 >= 0, -sp_y + 1 >= 0, sp_x >= 0, sp_y >= 0))


class TestEmpty:

    def test_repr(self):
        self.assertEqual(repr(Empty), 'Empty')

    def test_isempty(self):
        self.assertTrue(Empty.isempty())

    def test_isuniverse(self):
        self.assertFalse(Empty.isuniverse())


class TestUniverse:

    def test_repr(self):
        self.assertEqual(repr(Universe), 'Universe')

    def test_isempty(self):
        self.assertTrue(Universe.isempty())

    def test_isuniverse(self):
        self.assertTrue(Universe.isuniverse())