import contextlib
import collections
import pickle
import re
import sys
from unittest import TestCase, main, skipUnless, SkipTest, skip
from copy import copy, deepcopy

from typing import Any, NoReturn
from typing import TypeVar, AnyStr
from typing import T, KT, VT  # Not in __all__.
from typing import Union, Optional, Literal
from typing import Tuple, List, MutableMapping
from typing import Callable
from typing import Generic, ClassVar, Final, final, Protocol
from typing import cast, runtime_checkable
from typing import get_type_hints
from typing import get_origin, get_args
from typing import no_type_check, no_type_check_decorator
from typing import Type
from typing import NewType
from typing import NamedTuple, TypedDict
from typing import IO, TextIO, BinaryIO
from typing import Pattern, Match
import abc
import typing
import weakref
import types

from test import mod_generics_cache


class BaseTestCase(TestCase):

    def assertIsSubclass(self, cls, class_or_tuple, msg=None):
        if not issubclass(cls, class_or_tuple):
            message = '%r is not a subclass of %r' % (cls, class_or_tuple)
            if msg is not None:
                message += ' : %s' % msg
            raise self.failureException(message)

    def assertNotIsSubclass(self, cls, class_or_tuple, msg=None):
        if issubclass(cls, class_or_tuple):
            message = '%r is a subclass of %r' % (cls, class_or_tuple)
            if msg is not None:
                message += ' : %s' % msg
            raise self.failureException(message)

    def clear_caches(self):
        for f in typing._cleanups:
            f()


class Employee:
    pass


class Manager(Employee):
    pass


class Founder(Employee):
    pass


class ManagingFounder(Manager, Founder):
    pass


class AnyTests(BaseTestCase):

    def test_any_instance_type_error(self):
        with self.assertRaises(TypeError):
            isinstance(42, Any)

    def test_any_subclass_type_error(self):
        with self.assertRaises(TypeError):
            issubclass(Employee, Any)
        with self.assertRaises(TypeError):
            issubclass(Any, Employee)

    def test_repr(self):
        self.assertEqual(repr(Any), 'typing.Any')

    def test_errors(self):
        with self.assertRaises(TypeError):
            issubclass(42, Any)
        with self.assertRaises(TypeError):
            Any[int]  # Any is not a generic type.

    def test_cannot_subclass(self):
        with self.assertRaises(TypeError):
            class A(Any):
                pass
        with self.assertRaises(TypeError):
            class A(type(Any)):
                pass

    def test_cannot_instantiate(self):
        with self.assertRaises(TypeError):
            Any()
        with self.assertRaises(TypeError):
            type(Any)()

    def test_any_works_with_alias(self):
        # These expressions must simply not fail.
        typing.Match[Any]
        typing.Pattern[Any]
        typing.IO[Any]


class NoReturnTests(BaseTestCase):

    def test_noreturn_instance_type_error(self):
        with self.assertRaises(TypeError):
            isinstance(42, NoReturn)

    def test_noreturn_subclass_type_error(self):
        with self.assertRaises(TypeError):
            issubclass(Employee, NoReturn)
        with self.assertRaises(TypeError):
            issubclass(NoReturn, Employee)

    def test_repr(self):
        self.assertEqual(repr(NoReturn), 'typing.NoReturn')

    def test_not_generic(self):
        with self.assertRaises(TypeError):
            NoReturn[int]

    def test_cannot_subclass(self):
        with self.assertRaises(TypeError):
            class A(NoReturn):
                pass
        with self.assertRaises(TypeError):
            class A(type(NoReturn)):
                pass

    def test_cannot_instantiate(self):
        with self.assertRaises(TypeError):
            NoReturn()
        with self.assertRaises(TypeError):
            type(NoReturn)()


class TypeVarTests(BaseTestCase):

    def test_basic_plain(self):
        T = TypeVar('T')
        # T equals itself.
        self.assertEqual(T, T)
        # T is an instance of TypeVar
        self.assertIsInstance(T, TypeVar)

    def test_typevar_instance_type_error(self):
        T = TypeVar('T')
        with self.assertRaises(TypeError):
            isinstance(42, T)

    def test_typevar_subclass_type_error(self):
        T = TypeVar('T')
        with self.assertRaises(TypeError):
            issubclass(int, T)
        with self.assertRaises(TypeError):
            issubclass(T, int)

    def test_constrained_error(self):
        with self.assertRaises(TypeError):
            X = TypeVar('X', int)
            X

    def test_union_unique(self):
        X = TypeVar('X')
        Y = TypeVar('Y')
        self.assertNotEqual(X, Y)
        self.assertEqual(Union[X], X)
        self.assertNotEqual(Union[X], Union[X, Y])
        self.assertEqual(Union[X, X], X)
        self.assertNotEqual(Union[X, int], Union[X])
        self.assertNotEqual(Union[X, int], Union[int])
        self.assertEqual(Union[X, int].__args__, (X, int))
        self.assertEqual(Union[X, int].__parameters__, (X,))
        self.assertIs(Union[X, int].__origin__, Union)

    def test_union_constrained(self):
        A = TypeVar('A', str, bytes)
        self.assertNotEqual(Union[A, str], Union[A])

    def test_repr(self):
        self.assertEqual(repr(T), '~T')
        self.assertEqual(repr(KT), '~KT')
        self.assertEqual(repr(VT), '~VT')
        self.assertEqual(repr(AnyStr), '~AnyStr')
        T_co = TypeVar('T_co', covariant=True)
        self.assertEqual(repr(T_co), '+T_co')
        T_contra = TypeVar('T_contra', contravariant=True)
        self.assertEqual(repr(T_contra), '-T_contra')

    def test_no_redefinition(self):
        self.assertNotEqual(TypeVar('T'), TypeVar('T'))
        self.assertNotEqual(TypeVar('T', int, str), TypeVar('T', int, str))

    def test_cannot_subclass_vars(self):
        with self.assertRaises(TypeError):
            class V(TypeVar('T')):
                pass

    def test_cannot_subclass_var_itself(self):
        with self.assertRaises(TypeError):
            class V(TypeVar):
                pass

    def test_cannot_instantiate_vars(self):
        with self.assertRaises(TypeError):
            TypeVar('A')()

    def test_bound_errors(self):
        with self.assertRaises(TypeError):
            TypeVar('X', bound=42)
        with self.assertRaises(TypeError):
            TypeVar('X', str, float, bound=Employee)

    def test_missing__name__(self):
        # See bpo-39942
        code = ("import typing\n"
                "T = typing.TypeVar('T')\n"
                )
        exec(code, {})

    def test_no_bivariant(self):
        with self.assertRaises(ValueError):
            TypeVar('T', covariant=True, contravariant=True)


class UnionTests(BaseTestCase):

    def test_basics(self):
        u = Union[int, float]
        self.assertNotEqual(u, Union)

    def test_subclass_error(self):
        with self.assertRaises(TypeError):
            issubclass(int, Union)
        with self.assertRaises(TypeError):
            issubclass(Union, int)
        with self.assertRaises(TypeError):
            issubclass(int, Union[int, str])
        with self.assertRaises(TypeError):
            issubclass(Union[int, str], int)

    def test_union_any(self):
        u = Union[Any]
        self.assertEqual(u, Any)
        u1 = Union[int, Any]
        u2 = Union[Any, int]
        u3 = Union[Any, object]
        self.assertEqual(u1, u2)
        self.assertNotEqual(u1, Any)
        self.assertNotEqual(u2, Any)
        self.assertNotEqual(u3, Any)

    def test_union_object(self):
        u = Union[object]
        self.assertEqual(u, object)
        u1 = Union[int, object]
        u2 = Union[object, int]
        self.assertEqual(u1, u2)
        self.assertNotEqual(u1, object)
        self.assertNotEqual(u2, object)

    def test_unordered(self):
        u1 = Union[int, float]
        u2 = Union[float, int]
        self.assertEqual(u1, u2)

    def test_single_class_disappears(self):
        t = Union[Employee]
        self.assertIs(t, Employee)

    def test_base_class_kept(self):
        u = Union[Employee, Manager]
        self.assertNotEqual(u, Employee)
        self.assertIn(Employee, u.__args__)
        self.assertIn(Manager, u.__args__)

    def test_union_union(self):
        u = Union[int, float]
        v = Union[u, Employee]
        self.assertEqual(v, Union[int, float, Employee])

    def test_repr(self):
        self.assertEqual(repr(Union), 'typing.Union')
        u = Union[Employee, int]
        self.assertEqual(repr(u), 'typing.Union[%s.Employee, int]' % __name__)
        u = Union[int, Employee]
        self.assertEqual(repr(u), 'typing.Union[int, %s.Employee]' % __name__)
        T = TypeVar('T')
        u = Union[T, int][int]
        self.assertEqual(repr(u), repr(int))
        u = Union[List[int], int]
        self.assertEqual(repr(u), 'typing.Union[typing.List[int], int]')

    def test_cannot_subclass(self):
        with self.assertRaises(TypeError):
            class C(Union):
                pass
        with self.assertRaises(TypeError):
            class C(type(Union)):
                pass
        with self.assertRaises(TypeError):
            class C(Union[int, str]):
                pass

    def test_cannot_instantiate(self):
        with self.assertRaises(TypeError):
            Union()
        with self.assertRaises(TypeError):
            type(Union)()
        u = Union[int, float]
        with self.assertRaises(TypeError):
            u()
        with self.assertRaises(TypeError):
            type(u)()

    def test_union_generalization(self):
        self.assertFalse(Union[str, typing.Iterable[int]] == str)
        self.assertFalse(Union[str, typing.Iterable[int]] == typing.Iterable[int])
        self.assertIn(str, Union[str, typing.Iterable[int]].__args__)
        self.assertIn(typing.Iterable[int], Union[str, typing.Iterable[int]].__args__)

    def test_union_compare_other(self):
        self.assertNotEqual(Union, object)
        self.assertNotEqual(Union, Any)
        self.assertNotEqual(ClassVar, Union)
        self.assertNotEqual(Optional, Union)
        self.assertNotEqual([None], Optional)
        self.assertNotEqual(Optional, typing.Mapping)
        self.assertNotEqual(Optional[typing.MutableMapping], Union)

    def test_optional(self):
        o = Optional[int]
        u = Union[int, None]
        self.assertEqual(o, u)

    def test_empty(self):