import itertools

from pint.compat import np
from pint.converters import (
    Converter,
    LogarithmicConverter,
    OffsetConverter,
    ScaleConverter,
)
from pint.testsuite import helpers


class TestConverter:
    def test_converter(self):
        c = Converter()
        assert c.is_multiplicative
        assert not c.is_logarithmic
        assert c.to_reference(8)
        assert c.from_reference(8)

    def test_multiplicative_converter(self):
        c = ScaleConverter(20.0)
        assert c.is_multiplicative
        assert not c.is_logarithmic
        assert c.from_reference(c.to_reference(100)) == 100
        assert c.to_reference(c.from_reference(100)) == 100

    def test_offset_converter(self):
        c = OffsetConverter(20.0, 2)
        assert not c.is_multiplicative
        assert not c.is_logarithmic
        assert c.from_reference(c.to_reference(100)) == 100
        assert c.to_reference(c.from_reference(100)) == 100

    def test_log_converter(self):
        c = LogarithmicConverter(scale=1, logbase=10, logfactor=1)
        assert not c.is_multiplicative
        assert c.is_logarithmic
        assert round(abs(c.to_reference(0) - 1), 7) == 0
        assert round(abs(c.to_reference(1) - 10), 7) == 0
        assert round(abs(c.to_reference(2) - 100), 7) == 0
        assert round(abs(c.from_reference(1) - 0), 7) == 0
        assert round(abs(c.from_reference(10) - 1), 7) == 0
        assert round(abs(c.from_reference(100) - 2), 7) == 0
        arb_value = 20.0
        assert (
            round(abs(c.from_reference(c.to_reference(arb_value)) - arb_value), 7) == 0
        )
        assert (
            round(abs(c.to_reference(c.from_reference(arb_value)) - arb_value), 7) == 0
        )

    @helpers.requires_numpy
    def test_converter_inplace(self):
        for c in (ScaleConverter(20.0), OffsetConverter(20.0, 2)):
            fun1 = lambda x, y: c.from_reference(c.to_reference(x, y), y)
            fun2 = lambda x, y: c.to_reference(c.from_reference(x, y), y)
            for fun, (inplace, comp) in itertools.product(
                (fun1, fun2), ((True, True), (False, False))
            ):
                a = np.ones((1, 10))
                ac = np.ones((1, 10))
                r = fun(a, inplace)
                np.testing.assert_allclose(r, ac)
                if comp:
                    assert a is r
                else:
                    assert a is not r

    @helpers.requires_numpy
    def test_log_converter_inplace(self):
        arb_value = 3.14
        c = LogarithmicConverter(scale=1, logbase=10, logfactor=1)

        from_to = lambda value, inplace: c.from_reference(
            c.to_reference(value, inplace), inplace
        )

        to_from = lambda value, inplace: c.to_reference(
            c.from_reference(value, inplace), inplace
        )

        for fun, (inplace, comp) in itertools.product(
            (from_to, to_from), ((True, True), (False, False))
        ):
            arb_array = arb_value * np.ones((1, 10))
            result = fun(arb_array, inplace)
            np.testing.assert_allclose(result, arb_array)
            if comp:
                assert arb_array is result
            else:
                assert arb_array is not result
