# Copyright 2014 MINES ParisTech
#
# This file is part of LinPy.
#
# LinPy 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.
#
# LinPy 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 LinPy.  If not, see <http://www.gnu.org/licenses/>.

import unittest

from fractions import Fraction

from ..linexprs import Dummy, LinExpr, Rational, Symbol, symbols
from .libhelper import requires_sympy


class TestLinExpr(unittest.TestCase):

    def setUp(self):
        self.x = Symbol('x')
        self.y = Symbol('y')
        self.z = Symbol('z')
        self.zero = LinExpr(constant=0)
        self.one = LinExpr(constant=1)
        self.pi = LinExpr(constant=Fraction(22, 7))
        self.expr = self.x - 2*self.y + 3

    def test_new(self):
        self.assertIsInstance(LinExpr(coefficients={self.x: 1}), Symbol)
        self.assertIsInstance(LinExpr(constant=self.pi), Rational)
        self.assertNotIsInstance(self.x + self.pi, Symbol)
        self.assertNotIsInstance(self.x + self.pi, Rational)
        xx = LinExpr({self.x: 2})
        self.assertNotIsInstance(xx, Symbol)
        with self.assertRaises(TypeError):
            LinExpr('x + y', 2)
        with self.assertRaises(TypeError):
            LinExpr({0: 2})
        with self.assertRaises(TypeError):
            LinExpr({'x': '2'})
        self.assertEqual(LinExpr(constant=1), LinExpr(constant=self.one))
        self.assertEqual(LinExpr(constant='1'), LinExpr(constant=self.one))
        with self.assertRaises(ValueError):
            LinExpr(constant='a')

    def test_coefficient(self):
        self.assertEqual(self.expr.coefficient(self.x), 1)
        self.assertEqual(self.expr.coefficient(self.y), -2)
        self.assertEqual(self.expr.coefficient(self.z), 0)
        with self.assertRaises(TypeError):
            self.expr.coefficients('x')
        with self.assertRaises(TypeError):
            self.expr.coefficient(0)
        with self.assertRaises(TypeError):
            self.expr.coefficient(self.expr)

    def test_getitem(self):
        self.assertEqual(self.expr[self.x], 1)
        self.assertEqual(self.expr[self.y], -2)
        self.assertEqual(self.expr[self.z], 0)
        with self.assertRaises(TypeError):
            self.assertEqual(self.expr['x'], 1)
        with self.assertRaises(TypeError):
            self.expr[0]
        with self.assertRaises(TypeError):
            self.expr[self.expr]

    def test_coefficients(self):
        self.assertListEqual(list(self.expr.coefficients()),
                             [(self.x, 1), (self.y, -2)])

    def test_constant(self):
        self.assertEqual(self.x.constant, 0)
        self.assertEqual(self.pi.constant, Fraction(22, 7))
        self.assertEqual(self.expr.constant, 3)

    def test_symbols(self):
        self.assertTupleEqual(self.x.symbols, (self.x,))
        self.assertTupleEqual(self.pi.symbols, ())
        self.assertTupleEqual(self.expr.symbols, (self.x, self.y))

    def test_dimension(self):
        self.assertEqual(self.x.dimension, 1)
        self.assertEqual(self.pi.dimension, 0)
        self.assertEqual(self.expr.dimension, 2)

    def test_isconstant(self):
        self.assertFalse(self.x.isconstant())
        self.assertTrue(self.pi.isconstant())
        self.assertFalse(self.expr.isconstant())

    def test_issymbol(self):
        self.assertTrue(self.x.issymbol())
        self.assertFalse(self.pi.issymbol())
        self.assertFalse(self.expr.issymbol())

    def test_values(self):
        self.assertListEqual(list(self.expr.values()), [1, -2, 3])

    def test_bool(self):
        self.assertTrue(self.x)
        self.assertFalse(self.zero)
        self.assertTrue(self.pi)
        self.assertTrue(self.expr)

    def test_pos(self):
        self.assertEqual(+self.expr, self.expr)

    def test_neg(self):
        self.assertEqual(-self.expr, -self.x + 2*self.y - 3)

    def test_add(self):
        self.assertEqual(self.x + Fraction(22, 7), self.x + self.pi)
        self.assertEqual(Fraction(22, 7) + self.x, self.x + self.pi)
        self.assertEqual(self.x + self.x, 2 * self.x)
        self.assertEqual(self.expr + 2*self.y, self.x + 3)

    def test_sub(self):
        self.assertEqual(self.x - self.x, 0)
        self.assertEqual(self.expr - 3, self.x - 2*self.y)
        self.assertEqual(0 - self.x, -self.x)

    def test_mul(self):
        self.assertEqual(self.pi * 7, 22)
        self.assertEqual(self.expr * 0, 0)
        self.assertEqual(0 * self.expr, 0)
        self.assertEqual(self.expr * 2, 2*self.x - 4*self.y + 6)
        with self.assertRaises(TypeError):
            self.x * self.x

    def test_truediv(self):
        with self.assertRaises(ZeroDivisionError):
            self.expr / 0
        self.assertEqual(self.expr / 2, self.x / 2 - self.y + Fraction(3, 2))
        with self.assertRaises(TypeError):
            self.x / self.x

    def test_eq(self):
        self.assertEqual(self.expr, self.expr)
        self.assertNotEqual(self.x, self.y)
        self.assertEqual(self.zero, 0)

    def test_scaleint(self):
        self.assertEqual((self.x + self.y/2 + self.z/3).scaleint(),
                         6*self.x + 3*self.y + 2*self.z)

    def test_subs(self):
        self.assertEqual(self.x.subs(self.x, 3), 3)
        self.assertEqual(self.x.subs(self.x, self.x), self.x)
        self.assertEqual(self.x.subs(self.x, self.y), self.y)
        self.assertEqual(self.x.subs(self.x, self.x + self.y), self.x + self.y)
        self.assertEqual(self.x.subs(self.y, 3), self.x)
        self.assertEqual(self.pi.subs(self.x, 3), self.pi)
        self.assertEqual(self.expr.subs(self.x, -3), -2 * self.y)
        self.assertEqual(self.expr.subs([(self.x, self.y), (self.y, self.x)]),
                         -2*self.x + self.y + 3)
        self.assertEqual(self.expr.subs({self.x: self.z, self.y: self.z}),
                         3 - self.z)
        self.assertEqual(self.expr.subs({self.x: self.z, self.y: self.z}),
                         3 - self.z)
        with self.assertRaises(TypeError):
            self.x.subs('x', 3)
        with self.assertRaises(TypeError):
            self.expr.subs([('x', self.z), ('y', self.z)])
        with self.assertRaises(TypeError):
            self.expr.subs({'x': self.z, 'y': self.z})
        with self.assertRaises(TypeError):
            self.expr.subs(self.x, 'x')

    def test_fromstring(self):
        self.assertEqual(LinExpr.fromstring('x'), self.x)
        self.assertEqual(LinExpr.fromstring('-x'), -self.x)
        self.assertEqual(LinExpr.fromstring('22/7'), self.pi)
        self.assertEqual(LinExpr.fromstring('x - 2y + 3'), self.expr)
        self.assertEqual(LinExpr.fromstring('x - (3-1)y + 3'), self.expr)
        self.assertEqual(LinExpr.fromstring('x - 2*y + 3'), self.expr)

    def test_repr(self):
        self.assertEqual(str(LinExpr()), '0')
        self.assertEqual(str(self.x), 'x')
        self.assertEqual(str(-self.x), '-x')
        self.assertEqual(str(self.pi), '22/7')
        self.assertEqual(str(self.expr), 'x - 2*y + 3')

    @requires_sympy
    def test_fromsympy(self):
        import sympy
        sp_x, sp_y = sympy.symbols('x y')
        self.assertEqual(LinExpr.fromsympy(sp_x), self.x)
        self.assertEqual(LinExpr.fromsympy(sympy.Rational(22, 7)), self.pi)
        self.assertEqual(LinExpr.fromsympy(sp_x - 2*sp_y + 3), self.expr)
        with self.assertRaises(TypeError):
            LinExpr.fromsympy(sp_x*sp_y)

    @requires_sympy
    def test_tosympy(self):
        import sympy
        sp_x, sp_y = sympy.symbols('x y')
        self.assertEqual(self.x.tosympy(), sp_x)
        self.assertEqual(self.pi.tosympy(), sympy.Rational(22, 7))
        self.assertEqual(self.expr.tosympy(), sp_x - 2*sp_y + 3)


class TestSymbol(unittest.TestCase):

    def setUp(self):
        self.x = Symbol('x')
        self.y = Symbol('y')

    def test_new(self):
        self.assertEqual(Symbol('x'), self.x)
        with self.assertRaises(TypeError):
            Symbol(self.x)
        with self.assertRaises(TypeError):
            Symbol(1)
        with self.assertRaises(SyntaxError):
            Symbol('1')
        with self.assertRaises(SyntaxError):
            Symbol('x.1')
        with self.assertRaises(SyntaxError):
            Symbol('x 1')
        Symbol('_')
        Symbol('_x')
        Symbol('x_1')

    def test_name(self):
        self.assertEqual(self.x.name, 'x')

    def test_issymbol(self):
        self.assertTrue(self.x.issymbol())

    def test_fromstring(self):
        self.assertEqual(Symbol.fromstring('x'), self.x)
        with self.assertRaises(SyntaxError):
            Symbol.fromstring('1')

    def test_repr(self):
        self.assertEqual(str(self.x), 'x')

    @requires_sympy
    def test_fromsympy(self):
        import sympy
        sp_x = sympy.Symbol('x')
        self.assertEqual(Symbol.fromsympy(sp_x), self.x)
        with self.assertRaises(TypeError):
            Symbol.fromsympy(sympy.Rational(22, 7))
        with self.assertRaises(TypeError):
            Symbol.fromsympy(2 * sp_x)
        with self.assertRaises(TypeError):
            Symbol.fromsympy(sp_x*sp_x)


class TestDummy(unittest.TestCase):

    def setUp(self):
        self.x = Dummy('x')

    def test_new(self):
        self.assertEqual(self.x.name, 'x')
        self.assertTrue(Dummy().name.startswith('Dummy'))

    def test_eq(self):
        self.assertEqual(self.x, self.x)
        self.assertNotEqual(self.x, Symbol('x'))
        self.assertNotEqual(Symbol('x'), self.x)
        self.assertNotEqual(self.x, Dummy('x'))
        self.assertNotEqual(Dummy(), Dummy())

    def test_repr(self):
        self.assertEqual(repr(self.x), '_x')
        dummy1 = Dummy()
        dummy2 = Dummy()
        self.assertTrue(repr(dummy1).startswith('_Dummy_'))
        self.assertNotEqual(repr(dummy1), repr(dummy2))


class TestSymbols(unittest.TestCase):

    def setUp(self):
        self.x = Symbol('x')
        self.y = Symbol('y')

    def test(self):
        self.assertTupleEqual(symbols('x y'), (self.x, self.y))
        self.assertTupleEqual(symbols('x,y'), (self.x, self.y))
        self.assertTupleEqual(symbols(['x', 'y']), (self.x, self.y))
        with self.assertRaises(TypeError):
            symbols(1)
        with self.assertRaises(TypeError):
            symbols(['a', 1])


class TestRational(unittest.TestCase):

    def setUp(self):
        self.zero = Rational(0)
        self.one = Rational(1)
        self.pi = Rational(22, 7)

    def test_new(self):
        self.assertEqual(Rational(), self.zero)
        self.assertEqual(Rational(1), self.one)
        self.assertEqual(Rational(self.pi), self.pi)
        self.assertEqual(Rational('22/7'), self.pi)

    def test_hash(self):
        self.assertEqual(hash(self.one), hash(1))
        self.assertEqual(hash(self.pi), hash(Fraction(22, 7)))

    def test_isconstant(self):
        self.assertTrue(self.zero.isconstant())

    def test_bool(self):
        self.assertFalse(self.zero)
        self.assertTrue(self.pi)

    def test_repr(self):
        self.assertEqual(repr(self.zero), '0')
        self.assertEqual(repr(self.one), '1')
        self.assertEqual(repr(self.pi), '22/7')

    @requires_sympy
    def test_fromsympy(self):
        import sympy
        self.assertEqual(Rational.fromsympy(sympy.Rational(22, 7)), self.pi)
        with self.assertRaises(TypeError):
            Rational.fromsympy(sympy.Symbol('x'))