# Licensed under a 3-clause BSD style license - see LICENSE.rst

import os

import numpy as np

from astropy.utils.decorators import deprecated

__all__ = [
    "assert_equal",
    "assert_almost_equal",
    "assert_true",
    "setup_function",
    "teardown_function",
    "has_isnan",
]

CWD = os.getcwd()
TEST_DIR = os.path.dirname(__file__)

has_isnan = True
try:
    from math import isnan
except ImportError:
    try:
        from numpy import isnan  # noqa: F401
    except ImportError:
        has_isnan = False
        print("Tests requiring isnan will fail")


def setup_function(function):
    os.chdir(TEST_DIR)


def teardown_function(function):
    os.chdir(CWD)


# Compatibility functions to convert from nose to pytest
def assert_equal(a, b):
    assert a == b


def assert_almost_equal(a, b, **kwargs):
    assert np.allclose(a, b, **kwargs)


def assert_true(a):
    assert a


def make_decorator(func):
    """
    Wraps a test decorator so as to properly replicate metadata
    of the decorated function, including nose's additional stuff
    (namely, setup and teardown).
    """

    def decorate(newfunc):
        if hasattr(func, "compat_func_name"):
            name = func.compat_func_name
        else:
            name = func.__name__
        newfunc.__dict__ = func.__dict__
        newfunc.__doc__ = func.__doc__
        newfunc.__module__ = func.__module__
        if not hasattr(newfunc, "compat_co_firstlineno"):
            try:
                newfunc.compat_co_firstlineno = func.func_code.co_firstlineno
            except AttributeError:
                newfunc.compat_co_firstlineno = func.__code__.co_firstlineno
        try:
            newfunc.__name__ = name
        except TypeError:
            # can't set func name in 2.3
            newfunc.compat_func_name = name
        return newfunc

    return decorate


@deprecated("5.1", alternative="pytest.raises")
def raises(*exceptions):
    """Test must raise one of expected exceptions to pass.

    Example use::

      @raises(TypeError, ValueError)
      def test_raises_type_error():
          raise TypeError("This test passes")

      @raises(Exception)
      def test_that_fails_by_passing():
          pass

    """
    valid = " or ".join([e.__name__ for e in exceptions])

    def decorate(func):
        name = func.__name__

        def newfunc(*arg, **kw):
            try:
                func(*arg, **kw)
            except exceptions:
                pass
            else:
                message = f"{name}() did not raise {valid}"
                raise AssertionError(message)

        newfunc = make_decorator(func)(newfunc)
        return newfunc

    return decorate