import abc
import builtins
import collections
import collections.abc
from itertools import permutations
import pickle
import sys
from test import support
import threading
import time
import typing
import unittest

import functools

py_functools = support.import_fresh_module('functools', blocked=['_functools'])
c_functools = support.import_fresh_module('functools', fresh=['_functools'])

decimal = support.import_fresh_module('decimal', fresh=['_decimal'])

import gc, random
gc.set_threshold(random.randint(1, 500))

class TestLRU:

    def test_pickle(self):
        cls = self.__class__
        for f in cls.cached_func[0], cls.cached_meth, cls.cached_staticmeth:
            for proto in range(pickle.HIGHEST_PROTOCOL + 1):
                with self.subTest(proto=proto, func=f):
                    f_copy = pickle.loads(pickle.dumps(f, proto))
                    self.assertIs(f_copy, f)



@py_functools.lru_cache()
def py_cached_func(x, y):
    return 3 * x + y

@c_functools.lru_cache()
def c_cached_func(x, y):
    return 3 * x + y


class TestLRUPy(TestLRU, unittest.TestCase):
    module = py_functools
    cached_func = py_cached_func,

    @module.lru_cache()
    def cached_meth(self, x, y):
        return 3 * x + y

    @staticmethod
    @module.lru_cache()
    def cached_staticmeth(x, y):
        return 3 * x + y


class TestSingleDispatch(unittest.TestCase):

    def test_c3_abc(self):
        c = collections.abc
        mro = functools._c3_mro
        class A(object):
            pass
        class B(A):
            def __len__(self):
                return 0   # implies Sized
        @c.Container.register
        class C(object):
            pass
        class D(object):
            pass   # unrelated
        class X(D, C, B):
            def __call__(self):
                pass   # implies Callable
        expected = [X, c.Callable, D, C, c.Container, B, c.Sized, A, object]
        for abcs in permutations([c.Sized, c.Callable, c.Container]):
            self.assertEqual(mro(X, abcs=abcs), expected)
        # unrelated ABCs don't appear in the resulting MRO
        many_abcs = [c.Mapping, c.Sized, c.Callable, c.Container, c.Iterable]
        self.assertEqual(mro(X, abcs=many_abcs), expected)

    def test_mro_conflicts(self):
        c = collections.abc
        @functools.singledispatch
        def g(arg):
            return "base"
        class O(c.Sized):
            def __len__(self):
                return 0
        o = O()
        self.assertEqual(g(o), "base")
        g.register(c.Iterable, lambda arg: "iterable")
        g.register(c.Container, lambda arg: "container")
        g.register(c.Sized, lambda arg: "sized")
        g.register(c.Set, lambda arg: "set")
        self.assertEqual(g(o), "sized")
        c.Iterable.register(O)
        self.assertEqual(g(o), "sized")   # because it's explicitly in __mro__
        c.Container.register(O)
        self.assertEqual(g(o), "sized")   # see above: Sized is in __mro__
        c.Set.register(O)
        self.assertEqual(g(o), "set")     # because c.Set is a subclass of
                                          # c.Sized and c.Container
        class P:
            pass
        p = P()
        self.assertEqual(g(p), "base")
        c.Iterable.register(P)
        self.assertEqual(g(p), "iterable")
        c.Container.register(P)
        with self.assertRaises(RuntimeError) as re_one:
            g(p)
        self.assertIn(
            str(re_one.exception),
            (("Ambiguous dispatch: <class 'collections.abc.Container'> "
              "or <class 'collections.abc.Iterable'>"),
             ("Ambiguous dispatch: <class 'collections.abc.Iterable'> "
              "or <class 'collections.abc.Container'>")),
        )
        class Q(c.Sized):
            def __len__(self):
                return 0
        q = Q()
        self.assertEqual(g(q), "sized")
        c.Iterable.register(Q)
        self.assertEqual(g(q), "sized")   # because it's explicitly in __mro__
        c.Set.register(Q)
        self.assertEqual(g(q), "set")     # because c.Set is a subclass of
                                          # c.Sized and c.Iterable
        @functools.singledispatch
        def h(arg):
            return "base"
        @h.register(c.Sized)
        def _(arg):
            return "sized"
        @h.register(c.Container)
        def _(arg):
            return "container"
        # Even though Sized and Container are explicit bases of MutableMapping,
        # this ABC is implicitly registered on defaultdict which makes all of
        # MutableMapping's bases implicit as well from defaultdict's
        # perspective.
        with self.assertRaises(RuntimeError) as re_two:
            h(collections.defaultdict(lambda: 0))
        self.assertIn(
            str(re_two.exception),
            (("Ambiguous dispatch: <class 'collections.abc.Container'> "
              "or <class 'collections.abc.Sized'>"),
             ("Ambiguous dispatch: <class 'collections.abc.Sized'> "
              "or <class 'collections.abc.Container'>")),
        )
        class R(collections.defaultdict):
            pass
        c.MutableSequence.register(R)
        @functools.singledispatch
        def i(arg):
            return "base"
        @i.register(c.MutableMapping)
        def _(arg):
            return "mapping"
        @i.register(c.MutableSequence)
        def _(arg):
            return "sequence"
        r = R()
        self.assertEqual(i(r), "sequence")
        class S:
            pass
        class T(S, c.Sized):
            def __len__(self):
                return 0
        t = T()
        self.assertEqual(h(t), "sized")
        c.Container.register(T)
        self.assertEqual(h(t), "sized")   # because it's explicitly in the MRO
        class U:
            def __len__(self):
                return 0
        u = U()
        self.assertEqual(h(u), "sized")   # implicit Sized subclass inferred
                                          # from the existence of __len__()
        c.Container.register(U)
        # There is no preference for registered versus inferred ABCs.
        with self.assertRaises(RuntimeError) as re_three:
            h(u)
        self.assertIn(
            str(re_three.exception),
            (("Ambiguous dispatch: <class 'collections.abc.Container'> "
              "or <class 'collections.abc.Sized'>"),
             ("Ambiguous dispatch: <class 'collections.abc.Sized'> "
              "or <class 'collections.abc.Container'>")),
        )
        class V(c.Sized, S):
            def __len__(self):
                return 0
        @functools.singledispatch
        def j(arg):
            return "base"
        @j.register(S)
        def _(arg):
            return "s"
        @j.register(c.Container)
        def _(arg):
            return "container"
        v = V()
        self.assertEqual(j(v), "s")
        c.Container.register(V)
        self.assertEqual(j(v), "container")   # because it ends up right after
                                              # Sized in the MRO