# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

from __future__ import absolute_import, division, print_function

from concurrent.futures import ThreadPoolExecutor
from tornado import gen
from tornado.ioloop import IOLoop
from tornado.testing import AsyncTestCase, gen_test
from tornado.test.util import unittest, skipBefore33, skipBefore35, exec_test

try:
    from tornado.platform.asyncio import asyncio
except ImportError:
    asyncio = None
else:
    from tornado.platform.asyncio import AsyncIOLoop, to_asyncio_future, AnyThreadEventLoopPolicy
    # This is used in dynamically-evaluated code, so silence pyflakes.
    to_asyncio_future


@unittest.skipIf(asyncio is None, "asyncio module not present")
class AsyncIOLoopTest(AsyncTestCase):
    def get_new_ioloop(self):
        io_loop = AsyncIOLoop()
        return io_loop

    def test_asyncio_callback(self):
        # Basic test that the asyncio loop is set up correctly.
        asyncio.get_event_loop().call_soon(self.stop)
        self.wait()

    @gen_test
    def test_asyncio_future(self):
        # Test that we can yield an asyncio future from a tornado coroutine.
        # Without 'yield from', we must wrap coroutines in ensure_future,
        # which was introduced during Python 3.4, deprecating the prior "async".
        if hasattr(asyncio, 'ensure_future'):
            ensure_future = asyncio.ensure_future
        else:
            # async is a reserved word in Python 3.7
            ensure_future = getattr(asyncio, 'async')

        x = yield ensure_future(
            asyncio.get_event_loop().run_in_executor(None, lambda: 42))
        self.assertEqual(x, 42)

    @skipBefore33
    @gen_test
    def test_asyncio_yield_from(self):
        # Test that we can use asyncio coroutines with 'yield from'
        # instead of asyncio.async(). This requires python 3.3 syntax.
        namespace = exec_test(globals(), locals(), """
        @gen.coroutine
        def f():
            event_loop = asyncio.get_event_loop()
            x = yield from event_loop.run_in_executor(None, lambda: 42)
            return x
        """)
        result = yield namespace['f']()
        self.assertEqual(result, 42)

    @skipBefore35
    def test_asyncio_adapter(self):
        # This test demonstrates that when using the asyncio coroutine
        # runner (i.e. run_until_complete), the to_asyncio_future
        # adapter is needed. No adapter is needed in the other direction,
        # as demonstrated by other tests in the package.
        @gen.coroutine
        def tornado_coroutine():
            yield gen.Task(self.io_loop.add_callback)
            raise gen.Return(42)
        native_coroutine_without_adapter = exec_test(globals(), locals(), """
        async def native_coroutine_without_adapter():
            return await tornado_coroutine()
        """)["native_coroutine_without_adapter"]

        native_coroutine_with_adapter = exec_test(globals(), locals(), """
        async def native_coroutine_with_adapter():
            return await to_asyncio_future(tornado_coroutine())
        """)["native_coroutine_with_adapter"]

        # Use the adapter, but two degrees from the tornado coroutine.
        native_coroutine_with_adapter2 = exec_test(globals(), locals(), """
        async def native_coroutine_with_adapter2():
            return await to_asyncio_future(native_coroutine_without_adapter())
        """)["native_coroutine_with_adapter2"]

        # Tornado supports native coroutines both with and without adapters
        self.assertEqual(
            self.io_loop.run_sync(native_coroutine_without_adapter),
            42)
        self.assertEqual(
            self.io_loop.run_sync(native_coroutine_with_adapter),
            42)
        self.assertEqual(
            self.io_loop.run_sync(native_coroutine_with_adapter2),
            42)

        # Asyncio only supports coroutines that yield asyncio-compatible
        # Futures (which our Future is since 5.0).
        self.assertEqual(
            asyncio.get_event_loop().run_until_complete(
                native_coroutine_without_adapter()),
            42)
        self.assertEqual(
            asyncio.get_event_loop().run_until_complete(
                native_coroutine_with_adapter()),
            42)
        self.assertEqual(
            asyncio.get_event_loop().run_until_complete(
                native_coroutine_with_adapter2()),
            42)


@unittest.skipIf(asyncio is None, "asyncio module not present")
class LeakTest(unittest.TestCase):
    def setUp(self):
        # Trigger a cleanup of the mapping so we start with a clean slate.
        AsyncIOLoop().close()
        # If we don't clean up after ourselves other tests may fail on
        # py34.
        self.orig_policy = asyncio.get_event_loop_policy()
        asyncio.set_event_loop_policy(asyncio.DefaultEventLoopPolicy())

    def tearDown(self):
        asyncio.get_event_loop().close()
        asyncio.set_event_loop_policy(self.orig_policy)

    def test_ioloop_close_leak(self):
        orig_count = len(IOLoop._ioloop_for_asyncio)
        for i in range(10):
            # Create and close an AsyncIOLoop using Tornado interfaces.
            loop = AsyncIOLoop()
            loop.close()
        new_count = len(IOLoop._ioloop_for_asyncio) - orig_count
        self.assertEqual(new_count, 0)

    def test_asyncio_close_leak(self):
        orig_count = len(IOLoop._ioloop_for_asyncio)
        for i in range(10):
            # Create and close an AsyncIOMainLoop using asyncio interfaces.
            loop = asyncio.new_event_loop()
            loop.call_soon(IOLoop.current)
            loop.call_soon(loop.stop)
            loop.run_forever()
            loop.close()
        new_count = len(IOLoop._ioloop_for_asyncio) - orig_count
        # Because the cleanup is run on new loop creation, we have one
        # dangling entry in the map (but only one).
        self.assertEqual(new_count, 1)


@unittest.skipIf(asyncio is None, "asyncio module not present")
class AnyThreadEventLoopPolicyTest(unittest.TestCase):
    def setUp(self):
        self.orig_policy = asyncio.get_event_loop_policy()
        self.executor = ThreadPoolExecutor(1)

    def tearDown(self):
        asyncio.set_event_loop_policy(self.orig_policy)
        self.executor.shutdown()

    def get_event_loop_on_thread(self):
        def get_and_close_event_loop():
            """Get the event loop. Close it if one is returned.

            Returns the (closed) event loop. This is a silly thing
            to do and leaves the thread in a broken state, but it's
            enough for this test. Closing the loop avoids resource
            leak warnings.
            """
            loop = asyncio.get_event_loop()
            loop.close()
            return loop
        future = self.executor.submit(get_and_close_event_loop)
        return future.result()

    def run_policy_test(self, accessor, expected_type):
        # With the default policy, non-main threads don't get an event
        # loop.
        self.assertRaises((RuntimeError, AssertionError),
                          self.executor.submit(accessor).result)
        # Set the policy and we can get a loop.
        asyncio.set_event_loop_policy(AnyThreadEventLoopPolicy())
        self.assertIsInstance(
            self.executor.submit(accessor).result(),
            expected_type)
        # Clean up to silence leak warnings. Always use asyncio since
        # IOLoop doesn't (currently) close the underlying loop.
        self.executor.submit(lambda: asyncio.get_event_loop().close()).result()

    def test_asyncio_accessor(self):
        self.run_policy_test(asyncio.get_event_loop, asyncio.AbstractEventLoop)

    def test_tornado_accessor(self):
        self.run_policy_test(IOLoop.current, IOLoop)
