import warnings

from multipledispatch.dispatcher import (
    Dispatcher,
    MDNotImplementedError,
    MethodDispatcher,
)
from multipledispatch.conflict import ambiguities
from multipledispatch.utils import raises


def identity(x):
    return x


def inc(x):
    return x + 1


def dec(x):
    return x - 1


def test_dispatcher():
    f = Dispatcher("f")
    f.add((int,), inc)
    f.add((float,), dec)

    with warnings.catch_warnings():
        warnings.simplefilter("ignore", DeprecationWarning)
        assert f.resolve((int,)) == inc
    assert f.dispatch(int) is inc

    assert f(1) == 2
    assert f(1.0) == 0.0


def test_union_types():
    f = Dispatcher("f")
    f.register((int, float))(inc)

    assert f(1) == 2
    assert f(1.0) == 2.0


def test_dispatcher_as_decorator():
    f = Dispatcher("f")

    @f.register(int)
    def inc(x):
        return x + 1

    @f.register(float)
    def dec(x):
        return x - 1

    assert f(1) == 2
    assert f(1.0) == 0.0


def test_register_instance_method():
    class Test(object):
        __init__ = MethodDispatcher("f")

        @__init__.register(list)
        def _init_list(self, data):
            self.data = data

        @__init__.register(object)
        def _init_obj(self, datum):
            self.data = [datum]

    a = Test(3)
    b = Test([3])
    assert a.data == b.data


def test_on_ambiguity():
    f = Dispatcher("f")

    def identity(x):
        return x

    ambiguities = [False]

    def on_ambiguity(dispatcher, amb):
        ambiguities[0] = True

    f.add((object, object), identity)
    f.add((object, float), identity)
    f.add((float, object), identity)

    assert not ambiguities[0]
    f.reorder(on_ambiguity=on_ambiguity)
    assert ambiguities[0]


def test_serializable():
    f = Dispatcher("f")
    f.add((int,), inc)
    f.add((float,), dec)
    f.add((object,), identity)

    import pickle

    assert isinstance(pickle.dumps(f), (str, bytes))

    g = pickle.loads(pickle.dumps(f))

    assert g(1) == 2
    assert g(1.0) == 0.0
    assert g("hello") == "hello"


def test_raise_error_on_non_class():
    f = Dispatcher("f")
    assert raises(TypeError, lambda: f.add((1,), inc))


def test_docstring():
    def one(x, y):
        """Docstring number one"""
        return x + y

    def two(x, y):
        """Docstring number two"""
        return x + y

    def three(x, y):
        return x + y

    master_doc = "Doc of the multimethod itself"

    f = Dispatcher("f", doc=master_doc)
    f.add((object, object), one)
    f.add((int, int), two)
    f.add((float, float), three)

    assert one.__doc__.strip() in f.__doc__
    assert two.__doc__.strip() in f.__doc__
    assert f.__doc__.find(one.__doc__.strip()) < f.__doc__.find(two.__doc__.strip())
    assert "object, object" in f.__doc__
    assert master_doc in f.__doc__


def test_help():
    def one(x, y):
        """Docstring number one"""
        return x + y

    def two(x, y):
        """Docstring number two"""
        return x + y

    def three(x, y):
        """Docstring number three"""
        return x + y

    master_doc = "Doc of the multimethod itself"

    f = Dispatcher("f", doc=master_doc)
    f.add((object, object), one)
    f.add((int, int), two)
    f.add((float, float), three)

    assert f._help(1, 1) == two.__doc__
    assert f._help(1.0, 2.0) == three.__doc__


def test_source():
    def one(x, y):
        """Docstring number one"""
        return x + y

    def two(x, y):
        """Docstring number two"""
        return x - y

    master_doc = "Doc of the multimethod itself"

    f = Dispatcher("f", doc=master_doc)
    f.add((int, int), one)
    f.add((float, float), two)

    assert "x + y" in f._source(1, 1)
    assert "x - y" in f._source(1.0, 1.0)


def test_source_raises_on_missing_function():
    f = Dispatcher("f")

    assert raises(TypeError, lambda: f.source(1))


def test_no_implementations():
    f = Dispatcher("f")
    assert raises(NotImplementedError, lambda: f("hello"))


def test_register_stacking():
    f = Dispatcher("f")

    @f.register(list)
    @f.register(tuple)
    def rev(x):
        return x[::-1]

    assert f((1, 2, 3)) == (3, 2, 1)
    assert f([1, 2, 3]) == [3, 2, 1]

    assert raises(NotImplementedError, lambda: f("hello"))
    assert rev("hello") == "olleh"


def test_dispatch_method():
    f = Dispatcher("f")

    @f.register(list)
    def rev(x):
        return x[::-1]

    @f.register(int, int)
    def add(x, y):
        return x + y

    class MyList(list):
        pass

    assert f.dispatch(list) is rev
    assert f.dispatch(MyList) is rev
    assert f.dispatch(int, int) is add


def test_not_implemented():
    f = Dispatcher("f")

    @f.register(object)
    def _1(x):
        return "default"

    @f.register(int)
    def _2(x):
        if x % 2 == 0:
            return "even"
        else:
            raise MDNotImplementedError()

    assert f("hello") == "default"  # default behavior
    assert f(2) == "even"  # specialized behavior
    assert f(3) == "default"  # fall back to default behavior
    assert raises(NotImplementedError, lambda: f(1, 2))


def test_not_implemented_error():
    f = Dispatcher("f")

    @f.register(float)
    def _(a):
        raise MDNotImplementedError()

    assert raises(NotImplementedError, lambda: f(1.0))


def test_vararg_not_last_element_of_signature():
    f = Dispatcher("f")
    assert raises(TypeError, lambda: f.register([float], str)(lambda: None))


def test_vararg_has_multiple_elements():
    f = Dispatcher("f")
    assert raises(TypeError, lambda: f.register([float, str])(lambda: None))


def test_vararg_dispatch_simple():
    f = Dispatcher("f")

    @f.register([float])
    def _1(*args):
        return args

    assert f(1.0) == (1.0,)
    assert f(1.0, 2.0, 3.0) == (1.0, 2.0, 3.0)


def test_vararg_dispatch_ambiguity():
    f = Dispatcher("f")

    @f.register(float, object, [int])
    def _1(a, b, *args):
        return 1

    @f.register(object, float, [int])
    def _2(a, b, *args):
        return 2

    assert ambiguities(f.funcs)


def test_vararg_dispatch_ambiguity_in_variadic():
    f = Dispatcher("f")

    @f.register(float, [object])
    def _1(a, b, *args):
        return 1

    @f.register(object, [float])
    def _2(a, b, *args):
        return 2

    assert ambiguities(f.funcs)


def test_vararg_dispatch_multiple_types_explicit_args():
    f = Dispatcher("f")

    @f.register(str, [float])
    def _1(a, *b):
        return (a, b)

    result = f("a", 1.0, 2.0, 3.0)
    assert result == ("a", (1.0, 2.0, 3.0))


def test_vararg_dispatch_multiple_implementations():
    f = Dispatcher("f")

    @f.register(str, [float])
    def _1(a, *b):
        return "mixed_string_floats"

    @f.register([float])
    def _2(*b):
        return "floats"

    @f.register([str])
    def _3(*strings):
        return "strings"

    assert f("a", 1.0, 2.0) == "mixed_string_floats"
    assert f(1.0, 2.0, 3.14) == "floats"
    assert f("a", "b", "c") == "strings"


def test_vararg_dispatch_unions():
    f = Dispatcher("f")

    @f.register(str, [(int, float)])
    def _1(a, *b):
        return "mixed_string_ints_floats"

    @f.register([str])
    def _2(*strings):
        return "strings"

    @f.register([(str, int)])
    def _3(*strings_ints):
        return "mixed_strings_ints"

    @f.register([object])
    def _4(*objects):
        return "objects"

    assert f("a", 1.0, 7, 2.0, 11) == "mixed_string_ints_floats"
    assert f("a", "b", "c") == "strings"
    assert f("a", 1, "b", 2) == "mixed_strings_ints"
    assert f([], (), {}) == "objects"


def test_vararg_no_args():
    f = Dispatcher("f")

    @f.register([str])
    def _1(*strings):
        return "strings"

    assert f() == "strings"


def test_vararg_no_args_failure():
    f = Dispatcher("f")

    @f.register(str, [str])
    def _2(*strings):
        return "strings"

    assert raises(NotImplementedError, f)


def test_vararg_no_args_failure_2():
    f = Dispatcher("f")

    @f.register([str])
    def _2(*strings):
        return "strings"

    assert raises(NotImplementedError, lambda: f("a", "b", 1))


def test_vararg_ordering():
    f = Dispatcher("f")

    @f.register(str, int, [object])
    def _1(string, integer, *objects):
        return 1

    @f.register(str, [object])
    def _2(string, *objects):
        return 2

    @f.register([object])
    def _3(*objects):
        return 3

    assert f("a", 1) == 1
    assert f("a", 1, ["a"]) == 1
    assert f("a", 1, "a") == 1
    assert f("a", "a") == 2
    assert f("a") == 2
    assert f("a", ["a"]) == 2
    assert f(1) == 3
    assert f() == 3