import signal
import pytest

import trio
from .. import _core
from .._core.tests.tutil import ignore_coroutine_never_awaited_warnings
from .._util import (
    signal_raise,
    ConflictDetector,
    is_main_thread,
    coroutine_or_error,
    generic_function,
    Final,
    NoPublicConstructor,
)
from ..testing import wait_all_tasks_blocked


def test_signal_raise():
    record = []

    def handler(signum, _):
        record.append(signum)

    old = signal.signal(signal.SIGFPE, handler)
    try:
        signal_raise(signal.SIGFPE)
    finally:
        signal.signal(signal.SIGFPE, old)
    assert record == [signal.SIGFPE]


async def test_ConflictDetector():
    ul1 = ConflictDetector("ul1")
    ul2 = ConflictDetector("ul2")

    with ul1:
        with ul2:
            print("ok")

    with pytest.raises(_core.BusyResourceError) as excinfo:
        with ul1:
            with ul1:
                pass  # pragma: no cover
    assert "ul1" in str(excinfo.value)

    async def wait_with_ul1():
        with ul1:
            await wait_all_tasks_blocked()

    with pytest.raises(_core.BusyResourceError) as excinfo:
        async with _core.open_nursery() as nursery:
            nursery.start_soon(wait_with_ul1)
            nursery.start_soon(wait_with_ul1)
    assert "ul1" in str(excinfo.value)


def test_module_metadata_is_fixed_up():
    import trio
    import trio.testing

    assert trio.Cancelled.__module__ == "trio"
    assert trio.open_nursery.__module__ == "trio"
    assert trio.abc.Stream.__module__ == "trio.abc"
    assert trio.lowlevel.wait_task_rescheduled.__module__ == "trio.lowlevel"
    assert trio.testing.trio_test.__module__ == "trio.testing"

    # Also check methods
    assert trio.lowlevel.ParkingLot.__init__.__module__ == "trio.lowlevel"
    assert trio.abc.Stream.send_all.__module__ == "trio.abc"

    # And names
    assert trio.Cancelled.__name__ == "Cancelled"
    assert trio.Cancelled.__qualname__ == "Cancelled"
    assert trio.abc.SendStream.send_all.__name__ == "send_all"
    assert trio.abc.SendStream.send_all.__qualname__ == "SendStream.send_all"
    assert trio.to_thread.__name__ == "trio.to_thread"
    assert trio.to_thread.run_sync.__name__ == "run_sync"
    assert trio.to_thread.run_sync.__qualname__ == "run_sync"


async def test_is_main_thread():
    assert is_main_thread()

    def not_main_thread():
        assert not is_main_thread()

    await trio.to_thread.run_sync(not_main_thread)


# @coroutine is deprecated since python 3.8, which is fine with us.
@pytest.mark.filterwarnings("ignore:.*@coroutine.*:DeprecationWarning")
def test_coroutine_or_error():
    class Deferred:
        "Just kidding"

    with ignore_coroutine_never_awaited_warnings():

        async def f():  # pragma: no cover
            pass

        with pytest.raises(TypeError) as excinfo:
            coroutine_or_error(f())
        assert "expecting an async function" in str(excinfo.value)

        import asyncio

        @asyncio.coroutine
        def generator_based_coro():  # pragma: no cover
            yield from asyncio.sleep(1)

        with pytest.raises(TypeError) as excinfo:
            coroutine_or_error(generator_based_coro())
        assert "asyncio" in str(excinfo.value)

        with pytest.raises(TypeError) as excinfo:
            coroutine_or_error(asyncio.Future())
        assert "asyncio" in str(excinfo.value)

        with pytest.raises(TypeError) as excinfo:
            coroutine_or_error(lambda: asyncio.Future())
        assert "asyncio" in str(excinfo.value)

        with pytest.raises(TypeError) as excinfo:
            coroutine_or_error(Deferred())
        assert "twisted" in str(excinfo.value)

        with pytest.raises(TypeError) as excinfo:
            coroutine_or_error(lambda: Deferred())
        assert "twisted" in str(excinfo.value)

        with pytest.raises(TypeError) as excinfo:
            coroutine_or_error(len, [[1, 2, 3]])

        assert "appears to be synchronous" in str(excinfo.value)

        async def async_gen(arg):  # pragma: no cover
            yield

        with pytest.raises(TypeError) as excinfo:
            coroutine_or_error(async_gen, [0])
        msg = "expected an async function but got an async generator"
        assert msg in str(excinfo.value)

        # Make sure no references are kept around to keep anything alive
        del excinfo


def test_generic_function():
    @generic_function
    def test_func(arg):
        """Look, a docstring!"""
        return arg

    assert test_func is test_func[int] is test_func[int, str]
    assert test_func(42) == test_func[int](42) == 42
    assert test_func.__doc__ == "Look, a docstring!"
    assert test_func.__qualname__ == "test_generic_function.<locals>.test_func"
    assert test_func.__name__ == "test_func"
    assert test_func.__module__ == __name__


def test_final_metaclass():
    class FinalClass(metaclass=Final):
        pass

    with pytest.raises(TypeError):

        class SubClass(FinalClass):
            pass


def test_no_public_constructor_metaclass():
    class SpecialClass(metaclass=NoPublicConstructor):
        pass

    with pytest.raises(TypeError):
        SpecialClass()

    with pytest.raises(TypeError):

        class SubClass(SpecialClass):
            pass

    # Private constructor should not raise
    assert isinstance(SpecialClass._create(), SpecialClass)
