import functools
import importlib
import inspect
import pkgutil
import sys
import sysconfig
import types
import warnings

import pytest

import numpy
import numpy as np
from numpy.testing import IS_WASM
from numpy.testing._private.utils import run_subprocess

try:
    import ctypes
except ImportError:
    ctypes = None


def check_dir(module, module_name=None):
    """Returns a mapping of all objects with the wrong __module__ attribute."""
    if module_name is None:
        module_name = module.__name__
    results = {}
    for name in dir(module):
        if name == "core":
            continue
        item = getattr(module, name)
        if (hasattr(item, '__module__') and hasattr(item, '__name__')
                and item.__module__ != module_name):
            results[name] = item.__module__ + '.' + item.__name__
    return results


def test_numpy_namespace():
    # We override dir to not show these members
    allowlist = {
        'recarray': 'numpy.rec.recarray',
    }
    bad_results = check_dir(np)
    # pytest gives better error messages with the builtin assert than with
    # assert_equal
    assert bad_results == allowlist


@pytest.mark.skipif(IS_WASM, reason="can't start subprocess")
@pytest.mark.parametrize('name', ['testing'])
def test_import_lazy_import(name):
    """Make sure we can actually use the modules we lazy load.

    While not exported as part of the public API, it was accessible.  With the
    use of __getattr__ and __dir__, this isn't always true It can happen that
    an infinite recursion may happen.

    This is the only way I found that would force the failure to appear on the
    badly implemented code.

    We also test for the presence of the lazily imported modules in dir

    """
    exe = (sys.executable, '-c', "import numpy; numpy." + name)
    result = run_subprocess(exe)
    assert not result.stdout

    # Make sure they are still in the __dir__
    assert name in dir(np)


def test_dir_testing():
    """Assert that output of dir has only one "testing/tester"
    attribute without duplicate"""
    assert len(dir(np)) == len(set(dir(np)))


def test_numpy_linalg():
    bad_results = check_dir(np.linalg)
    assert bad_results == {}


def test_numpy_fft():
    bad_results = check_dir(np.fft)
    assert bad_results == {}


@pytest.mark.skipif(ctypes is None,
                    reason="ctypes not available in this python")
def test_NPY_NO_EXPORT():
    cdll = ctypes.CDLL(np._core._multiarray_tests.__file__)
    # Make sure an arbitrary NPY_NO_EXPORT function is actually hidden
    f = getattr(cdll, 'test_not_exported', None)
    assert f is None, ("'test_not_exported' is mistakenly exported, "
                      "NPY_NO_EXPORT does not work")


# Historically NumPy has not used leading underscores for private submodules
# much.  This has resulted in lots of things that look like public modules
# (i.e. things that can be imported as `import numpy.somesubmodule.somefile`),
# but were never intended to be public.  The PUBLIC_MODULES list contains
# modules that are either public because they were meant to be, or because they
# contain public functions/objects that aren't present in any other namespace
# for whatever reason and therefore should be treated as public.
#
# The PRIVATE_BUT_PRESENT_MODULES list contains modules that look public (lack
# of underscores) but should not be used.  For many of those modules the
# current status is fine.  For others it may make sense to work on making them
# private, to clean up our public API and avoid confusion.
PUBLIC_MODULES = ['numpy.' + s for s in [
    "ctypeslib",
    "dtypes",
    "exceptions",
    "f2py",
    "fft",
    "lib",
    "lib.array_utils",
    "lib.format",
    "lib.introspect",
    "lib.mixins",
    "lib.npyio",
    "lib.recfunctions",  # note: still needs cleaning, was forgotten for 2.0
    "lib.scimath",
    "lib.stride_tricks",
    "linalg",
    "ma",
    "ma.extras",
    "ma.mrecords",
    "polynomial",
    "polynomial.chebyshev",
    "polynomial.hermite",
    "polynomial.hermite_e",
    "polynomial.laguerre",
    "polynomial.legendre",
    "polynomial.polynomial",
    "random",
    "strings",
    "testing",
    "testing.overrides",
    "typing",
    "typing.mypy_plugin",
    "version",
]]


PUBLIC_ALIASED_MODULES = [
    "numpy.char",
    "numpy.emath",
    "numpy.rec",
]


PRIVATE_BUT_PRESENT_MODULES = ['numpy.' + s for s in [
    "conftest",
    "core",
    "core.multiarray",
    "core.numeric",
    "core.umath",
    "core.arrayprint",
    "core.defchararray",
    "core.einsumfunc",
    "core.fromnumeric",
    "core.function_base",
    "core.getlimits",
    "core.numerictypes",
    "core.overrides",
    "core.records",
    "core.shape_base",
    "f2py.auxfuncs",
    "f2py.capi_maps",
    "f2py.cb_rules",
    "f2py.cfuncs",
    "f2py.common_rules",
    "f2py.crackfortran",
    "f2py.diagnose",
    "f2py.f2py2e",
    "f2py.f90mod_rules",
    "f2py.func2subr",
    "f2py.rules",
    "f2py.symbolic",
    "f2py.use_rules",
    "lib.user_array",  # note: not in np.lib, but probably should just be deleted
    "linalg.lapack_lite",
    "ma.core",
    "ma.testutils",
    "matlib",
    "matrixlib",
    "matrixlib.defmatrix",
    "polynomial.polyutils",
    "random.mtrand",
    "random.bit_generator",
    "testing.print_coercion_tables",
]]


def is_unexpected(name):
    """Check if this needs to be considered."""
    return (
        '._' not in name and '.tests' not in name and '.setup' not in name
        and name not in PUBLIC_MODULES
        and name not in PUBLIC_ALIASED_MODULES
        and name not in PRIVATE_BUT_PRESENT_MODULES
    )


def test_all_modules_are_expected():
    """
    Test that we don't add anything that looks like a new public module by
    accident.  Check is based on filenames.
    """

    modnames = []
    for _, modname, ispkg in pkgutil.walk_packages(path=np.__path__,
                                                   prefix=np.__name__ + '.',
                                                   onerror=None):
        if is_unexpected(modname):
            # We have a name that is new.  If that's on purpose, add it to
            # PUBLIC_MODULES.  We don't expect to have to add anything to
            # PRIVATE_BUT_PRESENT_MODULES.  Use an underscore in the name!
            modnames.append(modname)

    if modnames:
        raise AssertionError(f'Found unexpected modules: {modnames}')


# Stuff that clearly shouldn't be in the API and is detected by the next test
# below
SKIP_LIST_2 = [
    'numpy.matlib.char',
    'numpy.matlib.rec',
    'numpy.matlib.emath',
    'numpy.matlib.exceptions',
    'numpy.matlib.math',
    'numpy.matlib.linalg',
    'numpy.matlib.fft',
    'numpy.matlib.random',
    'numpy.matlib.ctypeslib',
    'numpy.matlib.ma',
]


@pytest.mark.slow
def test_all_modules_are_expected_2():
    """
    Method checking all objects. The pkgutil-based method in
    `test_all_modules_are_expected` does not catch imports into a namespace,
    only filenames.  So this test is more thorough, and checks this like:

        import .lib.scimath as emath

    To check if something in a module is (effectively) public, one can check if
    there's anything in that namespace that's a public function/object but is
    not exposed in a higher-level namespace.  For example for a `numpy.lib`
    submodule::

        mod = np.lib.mixins
        for obj in mod.__all__:
            if obj in np.__all__:
                continue
            elif obj in np.lib.__all__:
                continue

            else:
                print(obj)

    """

    def find_unexpected_members(mod_name):
        members = []
        module = importlib.import_module(mod_name)
        if hasattr(module, '__all__'):
            objnames = module.__all__
        else:
            objnames = dir(module)

        for objname in objnames:
            if not objname.startswith('_'):
                fullobjname = mod_name + '.' + objname
                if isinstance(getattr(module, objname), types.ModuleType):
                    if is_unexpected(fullobjname):
                        if fullobjname not in SKIP_LIST_2:
                            members.append(fullobjname)

        return members

    unexpected_members = find_unexpected_members("numpy")
    for modname in PUBLIC_MODULES:
        unexpected_members.extend(find_unexpected_members(modname))

    if unexpected_members:
        raise AssertionError("Found unexpected object(s) that look like "
                             f"modules: {unexpected_members}")


def test_api_importable():
    """
    Check that all submodules listed higher up in this file can be imported

    Note that if a PRIVATE_BUT_PRESENT_MODULES entry goes missing, it may
    simply need to be removed from the list (deprecation may or may not be
    needed - apply common sense).
    """
    def check_importable(module_name):
        try:
            importlib.import_module(module_name)
        except (ImportError, AttributeError):
            return False

        return True

    module_names = []
    for module_name in PUBLIC_MODULES:
        if not check_importable(module_name):
            module_names.append(module_name)

    if module_names:
        raise AssertionError("Modules in the public API that cannot be "
                             f"imported: {module_names}")

    for module_name in PUBLIC_ALIASED_MODULES:
        try:
            eval(module_name)
        except AttributeError:
            module_names.append(module_name)

    if module_names:
        raise AssertionError("Modules in the public API that were not "
                             f"found: {module_names}")

    with warnings.catch_warnings(record=True) as w:
        warnings.filterwarnings('always', category=DeprecationWarning)
        warnings.filterwarnings('always', category=ImportWarning)
        for module_name in PRIVATE_BUT_PRESENT_MODULES:
            if not check_importable(module_name):
                module_names.append(module_name)

    if module_names:
        raise AssertionError("Modules that are not really public but looked "
                             "public and can not be imported: "
                             f"{module_names}")


@pytest.mark.xfail(
    sysconfig.get_config_var("Py_DEBUG") not in (None, 0, "0"),
    reason=(
        "NumPy possibly built with `USE_DEBUG=True ./tools/travis-test.sh`, "
        "which does not expose the `array_api` entry point. "
        "See https://github.com/numpy/numpy/pull/19800"
    ),
)
def test_array_api_entry_point():
    """
    Entry point for Array API implementation can be found with importlib and
    returns the main numpy namespace.
    """
    # For a development install that did not go through meson-python,
    # the entrypoint will not have been installed. So ensure this test fails
    # only if numpy is inside site-packages.
    numpy_in_sitepackages = sysconfig.get_path('platlib') in np.__file__

    eps = importlib.metadata.entry_points()
    xp_eps = eps.select(group="array_api")
    if len(xp_eps) == 0:
        if numpy_in_sitepackages:
            msg = "No entry points for 'array_api' found"
            raise AssertionError(msg) from None
        return

    try:
        ep = next(ep for ep in xp_eps if ep.name == "numpy")
    except StopIteration:
        if numpy_in_sitepackages:
            msg = "'numpy' not in array_api entry points"
            raise AssertionError(msg) from None
        return

    if ep.value == 'numpy.array_api':
        # Looks like the entrypoint for the current numpy build isn't
        # installed, but an older numpy is also installed and hence the
        # entrypoint is pointing to the old (no longer existing) location.
        # This isn't a problem except for when running tests with `spin` or an
        # in-place build.
        return

    xp = ep.load()
    msg = (
        f"numpy entry point value '{ep.value}' "
        "does not point to our Array API implementation"
    )
    assert xp is numpy, msg


def test_main_namespace_all_dir_coherence():
    """
    Checks if `dir(np)` and `np.__all__` are consistent and return
    the same content, excluding exceptions and private members.
    """
    def _remove_private_members(member_set):
        return {m for m in member_set if not m.startswith('_')}

    def _remove_exceptions(member_set):
        return member_set.difference({
            "bool"  # included only in __dir__
        })

    all_members = _remove_private_members(np.__all__)
    all_members = _remove_exceptions(all_members)

    dir_members = _remove_private_members(np.__dir__())
    dir_members = _remove_exceptions(dir_members)

    assert all_members == dir_members, (
        "Members that break symmetry: "
        f"{all_members.symmetric_difference(dir_members)}"
    )


@pytest.mark.filterwarnings(
    r"ignore:numpy.core(\.\w+)? is deprecated:DeprecationWarning"
)
def test_core_shims_coherence():
    """
    Check that all "semi-public" members of `numpy._core` are also accessible
    from `numpy.core` shims.
    """
    import numpy.core as core

    for member_name in dir(np._core):
        # Skip private and test members. Also if a module is aliased,
        # no need to add it to np.core
        if (
            member_name.startswith("_")
            or member_name in ["tests", "strings"]
            or f"numpy.{member_name}" in PUBLIC_ALIASED_MODULES
        ):
            continue

        member = getattr(np._core, member_name)

        # np.core is a shim and all submodules of np.core are shims
        # but we should be able to import everything in those shims
        # that are available in the "real" modules in np._core, with
        # the exception of the namespace packages (__spec__.origin is None),
        # like numpy._core.include, or numpy._core.lib.pkgconfig.
        if (
            inspect.ismodule(member)
            and member.__spec__ and member.__spec__.origin is not None
        ):
            submodule = member
            submodule_name = member_name
            for submodule_member_name in dir(submodule):
                # ignore dunder names
                if submodule_member_name.startswith("__"):
                    continue
                submodule_member = getattr(submodule, submodule_member_name)

                core_submodule = __import__(
                    f"numpy.core.{submodule_name}",
                    fromlist=[submodule_member_name]
                )

                assert submodule_member is getattr(
                    core_submodule, submodule_member_name
                )

        else:
            assert member is getattr(core, member_name)


@pytest.mark.filterwarnings(r"ignore:\w+ chararray \w+:DeprecationWarning")
def test_functions_single_location():
    """
    Check that each public function is available from one location only.

    Test performs BFS search traversing NumPy's public API. It flags
    any function-like object that is accessible from more that one place.
    """
    from collections.abc import Callable
    from typing import Any

    from numpy._core._multiarray_umath import (
        _ArrayFunctionDispatcher as dispatched_function,
    )

    visited_modules: set[types.ModuleType] = {np}
    visited_functions: set[Callable[..., Any]] = set()
    # Functions often have `__name__` overridden, therefore we need
    # to keep track of locations where functions have been found.
    functions_original_paths: dict[Callable[..., Any], str] = {}

    # Here we aggregate functions with more than one location.
    # It must be empty for the test to pass.
    duplicated_functions: list[tuple] = []

    modules_queue = [np]

    while len(modules_queue) > 0:

        module = modules_queue.pop()

        for member_name in dir(module):
            member = getattr(module, member_name)

            # first check if we got a module
            if (
                inspect.ismodule(member) and  # it's a module
                "numpy" in member.__name__ and  # inside NumPy
                not member_name.startswith("_") and  # not private
                "numpy._core" not in member.__name__ and  # outside _core
                # not a legacy or testing module
                member_name not in ["f2py", "ma", "testing", "tests"] and
                member not in visited_modules  # not visited yet
            ):
                modules_queue.append(member)
                visited_modules.add(member)

            # else check if we got a function-like object
            elif (
                inspect.isfunction(member) or
                isinstance(member, (dispatched_function, np.ufunc))
            ):
                if member in visited_functions:

                    # skip main namespace functions with aliases
                    if (
                        member.__name__ in [
                            "absolute",  # np.abs
                            "arccos",  # np.acos
                            "arccosh",  # np.acosh
                            "arcsin",  # np.asin
                            "arcsinh",  # np.asinh
                            "arctan",  # np.atan
                            "arctan2",  # np.atan2
                            "arctanh",  # np.atanh
                            "left_shift",  # np.bitwise_left_shift
                            "right_shift",  # np.bitwise_right_shift
                            "conjugate",  # np.conj
                            "invert",  # np.bitwise_not & np.bitwise_invert
                            "remainder",  # np.mod
                            "divide",  # np.true_divide
                            "concatenate",  # np.concat
                            "power",  # np.pow
                            "transpose",  # np.permute_dims
                        ] and
                        module.__name__ == "numpy"
                    ):
                        continue
                    # skip trimcoef from numpy.polynomial as it is
                    # duplicated by design.
                    if (
                        member.__name__ == "trimcoef" and
                        module.__name__.startswith("numpy.polynomial")
                    ):
                        continue

                    # skip ufuncs that are exported in np.strings as well
                    if member.__name__ in (
                        "add",
                        "equal",
                        "not_equal",
                        "greater",
                        "greater_equal",
                        "less",
                        "less_equal",
                    ) and module.__name__ == "numpy.strings":
                        continue

                    # numpy.char reexports all numpy.strings functions for
                    # backwards-compatibility
                    if module.__name__ == "numpy.char":
                        continue

                    # function is present in more than one location!
                    duplicated_functions.append(
                        (member.__name__,
                         module.__name__,
                         functions_original_paths[member])
                    )
                else:
                    visited_functions.add(member)
                    functions_original_paths[member] = module.__name__

    del visited_functions, visited_modules, functions_original_paths

    assert len(duplicated_functions) == 0, duplicated_functions


def test___module___attribute():
    modules_queue = [np]
    visited_modules = {np}
    visited_functions = set()
    incorrect_entries = []

    while len(modules_queue) > 0:
        module = modules_queue.pop()
        for member_name in dir(module):
            member = getattr(module, member_name)
            # first check if we got a module
            if (
                inspect.ismodule(member) and  # it's a module
                "numpy" in member.__name__ and  # inside NumPy
                not member_name.startswith("_") and  # not private
                "numpy._core" not in member.__name__ and  # outside _core
                # not in a skip module list
                member_name not in [
                    "char", "core", "f2py", "ma", "lapack_lite", "mrecords",
                    "testing", "tests", "polynomial", "typing", "mtrand",
                    "bit_generator",
                ] and
                member not in visited_modules  # not visited yet
            ):
                modules_queue.append(member)
                visited_modules.add(member)
            elif (
                not inspect.ismodule(member) and
                hasattr(member, "__name__") and
                not member.__name__.startswith("_") and
                member.__module__ != module.__name__ and
                member not in visited_functions
            ):
                # skip ufuncs that are exported in np.strings as well
                if member.__name__ in (
                    "add", "equal", "not_equal", "greater", "greater_equal",
                    "less", "less_equal",
                ) and module.__name__ == "numpy.strings":
                    continue

                # recarray and record are exported in np and np.rec
                if (
                    (member.__name__ == "recarray" and module.__name__ == "numpy") or
                    (member.__name__ == "record" and module.__name__ == "numpy.rec")
                ):
                    continue

                # ctypeslib exports ctypes c_long/c_longlong
                if (
                    member.__name__ in ("c_long", "c_longlong") and
                    module.__name__ == "numpy.ctypeslib"
                ):
                    continue

                # skip cdef classes
                if member.__name__ in (
                    "BitGenerator", "Generator", "MT19937", "PCG64", "PCG64DXSM",
                    "Philox", "RandomState", "SFC64", "SeedSequence",
                ):
                    continue

                incorrect_entries.append(
                    {
                        "Func": member.__name__,
                        "actual": member.__module__,
                        "expected": module.__name__,
                    }
                )
                visited_functions.add(member)

    if incorrect_entries:
        assert len(incorrect_entries) == 0, incorrect_entries


def _check_correct_qualname_and_module(obj) -> bool:
    qualname = obj.__qualname__
    name = obj.__name__
    module_name = obj.__module__
    assert name == qualname.split(".")[-1]

    module = sys.modules[module_name]
    actual_obj = functools.reduce(getattr, qualname.split("."), module)
    return (
        actual_obj is obj or
        # `obj` may be a bound method/property of `actual_obj`:
        (
            hasattr(actual_obj, "__get__") and hasattr(obj, "__self__") and
            actual_obj.__module__ == obj.__module__ and
            actual_obj.__qualname__ == qualname
        )
    )


@pytest.mark.filterwarnings(r"ignore:\w+ chararray \w+:DeprecationWarning")
def test___qualname___and___module___attribute():
    # NumPy messes with module and name/qualname attributes, but any object
    # should be discoverable based on its module and qualname, so test that.
    # We do this for anything with a name (ensuring qualname is also set).
    modules_queue = [np]
    visited_modules = {np}
    visited_functions = set()
    incorrect_entries = []

    while len(modules_queue) > 0:
        module = modules_queue.pop()
        for member_name in dir(module):
            member = getattr(module, member_name)
            # first check if we got a module
            if (
                inspect.ismodule(member) and  # it's a module
                "numpy" in member.__name__ and  # inside NumPy
                not member_name.startswith("_") and  # not private
                member_name not in {"tests", "typing"} and  # type names don't match
                "numpy._core" not in member.__name__ and  # outside _core
                member not in visited_modules  # not visited yet
            ):
                modules_queue.append(member)
                visited_modules.add(member)
            elif (
                not inspect.ismodule(member) and
                hasattr(member, "__name__") and
                not member.__name__.startswith("_") and
                not member_name.startswith("_") and
                not _check_correct_qualname_and_module(member) and
                member not in visited_functions
            ):
                incorrect_entries.append(
                    {
                        "found_at": f"{module.__name__}:{member_name}",
                        "advertises": f"{member.__module__}:{member.__qualname__}",
                    }
                )
                visited_functions.add(member)

    if incorrect_entries:
        assert len(incorrect_entries) == 0, incorrect_entries
