import inspect
import sys
import pytest

import numpy as np
from numpy.core import arange
from numpy.testing import assert_, assert_equal, assert_raises_regex
from numpy.lib import deprecate, deprecate_with_doc
import numpy.lib.utils as utils

from io import StringIO


@pytest.mark.skipif(sys.flags.optimize == 2, reason="Python running -OO")
@pytest.mark.skipif(
    sys.version_info == (3, 10, 0, "candidate", 1),
    reason="Broken as of bpo-44524",
)
def test_lookfor():
    out = StringIO()
    utils.lookfor('eigenvalue', module='numpy', output=out,
                  import_modules=False)
    out = out.getvalue()
    assert_('numpy.linalg.eig' in out)


@deprecate
def old_func(self, x):
    return x


@deprecate(message="Rather use new_func2")
def old_func2(self, x):
    return x


def old_func3(self, x):
    return x
new_func3 = deprecate(old_func3, old_name="old_func3", new_name="new_func3")


def old_func4(self, x):
    """Summary.

    Further info.
    """
    return x
new_func4 = deprecate(old_func4)


def old_func5(self, x):
    """Summary.

        Bizarre indentation.
    """
    return x
new_func5 = deprecate(old_func5, message="This function is\ndeprecated.")


def old_func6(self, x):
    """
    Also in PEP-257.
    """
    return x
new_func6 = deprecate(old_func6)


@deprecate_with_doc(msg="Rather use new_func7")
def old_func7(self,x):
    return x


def test_deprecate_decorator():
    assert_('deprecated' in old_func.__doc__)


def test_deprecate_decorator_message():
    assert_('Rather use new_func2' in old_func2.__doc__)


def test_deprecate_fn():
    assert_('old_func3' in new_func3.__doc__)
    assert_('new_func3' in new_func3.__doc__)


def test_deprecate_with_doc_decorator_message():
    assert_('Rather use new_func7' in old_func7.__doc__)


@pytest.mark.skipif(sys.flags.optimize == 2, reason="-OO discards docstrings")
@pytest.mark.parametrize('old_func, new_func', [
    (old_func4, new_func4),
    (old_func5, new_func5),
    (old_func6, new_func6),
])
def test_deprecate_help_indentation(old_func, new_func):
    _compare_docs(old_func, new_func)
    # Ensure we don't mess up the indentation
    for knd, func in (('old', old_func), ('new', new_func)):
        for li, line in enumerate(func.__doc__.split('\n')):
            if li == 0:
                assert line.startswith('    ') or not line.startswith(' '), knd
            elif line:
                assert line.startswith('    '), knd


def _compare_docs(old_func, new_func):
    old_doc = inspect.getdoc(old_func)
    new_doc = inspect.getdoc(new_func)
    index = new_doc.index('\n\n') + 2
    assert_equal(new_doc[index:], old_doc)


@pytest.mark.skipif(sys.flags.optimize == 2, reason="-OO discards docstrings")
def test_deprecate_preserve_whitespace():
    assert_('\n        Bizarre' in new_func5.__doc__)


def test_deprecate_module():
    assert_(old_func.__module__ == __name__)


def test_safe_eval_nameconstant():
    # Test if safe_eval supports Python 3.4 _ast.NameConstant
    utils.safe_eval('None')


class TestByteBounds:

    def test_byte_bounds(self):
        # pointer difference matches size * itemsize
        # due to contiguity
        a = arange(12).reshape(3, 4)
        low, high = utils.byte_bounds(a)
        assert_equal(high - low, a.size * a.itemsize)

    def test_unusual_order_positive_stride(self):
        a = arange(12).reshape(3, 4)
        b = a.T
        low, high = utils.byte_bounds(b)
        assert_equal(high - low, b.size * b.itemsize)

    def test_unusual_order_negative_stride(self):
        a = arange(12).reshape(3, 4)
        b = a.T[::-1]
        low, high = utils.byte_bounds(b)
        assert_equal(high - low, b.size * b.itemsize)

    def test_strided(self):
        a = arange(12)
        b = a[::2]
        low, high = utils.byte_bounds(b)
        # the largest pointer address is lost (even numbers only in the
        # stride), and compensate addresses for striding by 2
        assert_equal(high - low, b.size * 2 * b.itemsize - b.itemsize)


def test_assert_raises_regex_context_manager():
    with assert_raises_regex(ValueError, 'no deprecation warning'):
        raise ValueError('no deprecation warning')


def test_info_method_heading():
    # info(class) should only print "Methods:" heading if methods exist

    class NoPublicMethods:
        pass

    class WithPublicMethods:
        def first_method():
            pass

    def _has_method_heading(cls):
        out = StringIO()
        utils.info(cls, output=out)
        return 'Methods:' in out.getvalue()

    assert _has_method_heading(WithPublicMethods)
    assert not _has_method_heading(NoPublicMethods)


def test_drop_metadata():
    def _compare_dtypes(dt1, dt2):
        return np.can_cast(dt1, dt2, casting='no')

    # structured dtype
    dt = np.dtype([('l1', [('l2', np.dtype('S8', metadata={'msg': 'toto'}))])],
                  metadata={'msg': 'titi'})
    dt_m = utils.drop_metadata(dt)
    assert _compare_dtypes(dt, dt_m) is True
    assert dt_m.metadata is None
    assert dt_m['l1'].metadata is None
    assert dt_m['l1']['l2'].metadata is None
    
    # alignement
    dt = np.dtype([('x', '<f8'), ('y', '<i4')],
                  align=True,
                  metadata={'msg': 'toto'})
    dt_m = utils.drop_metadata(dt)
    assert _compare_dtypes(dt, dt_m) is True
    assert dt_m.metadata is None

    # subdtype
    dt = np.dtype('8f',
                  metadata={'msg': 'toto'})
    dt_m = utils.drop_metadata(dt)
    assert _compare_dtypes(dt, dt_m) is True
    assert dt_m.metadata is None

    # scalar
    dt = np.dtype('uint32',
                  metadata={'msg': 'toto'})
    dt_m = utils.drop_metadata(dt)
    assert _compare_dtypes(dt, dt_m) is True
    assert dt_m.metadata is None


@pytest.mark.parametrize("dtype",
        [np.dtype("i,i,i,i")[["f1", "f3"]],
        np.dtype("f8"),
        np.dtype("10i")])
def test_drop_metadata_identity_and_copy(dtype):
    # If there is no metadata, the identity is preserved:
    assert utils.drop_metadata(dtype) is dtype

    # If there is any, it is dropped (subforms are checked above)
    dtype = np.dtype(dtype, metadata={1: 2})
    assert utils.drop_metadata(dtype).metadata is None