# -*- Mode: Python; py-indent-offset: 4 -*-
# vim: tabstop=4 shiftwidth=4 expandtab

import pytest
import platform
import unittest

import asyncio
from gi.repository import GLib, Gio
from gi.events import GLibEventLoopPolicy


class TestAsync(unittest.TestCase):

    def setUp(self):
        policy = GLibEventLoopPolicy()
        asyncio.set_event_loop_policy(policy)
        self.addCleanup(asyncio.set_event_loop_policy, None)
        self.loop = policy.get_event_loop()
        self.addCleanup(self.loop.close)

    def test_async_enumerate(self):
        f = Gio.file_new_for_path("./")

        called = False

        def cb():
            nonlocal called
            called = True

        async def run():
            nonlocal called, self

            self.loop.call_soon(cb)

            iter_info = []
            for info in await f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT):
                iter_info.append(info.get_name())

            # The await runs the mainloop and cb is called.
            self.assertEqual(called, True)

            next_info = []
            enumerator = f.enumerate_children("standard::*", 0, None)
            while True:
                info = enumerator.next_file(None)
                if info is None:
                    break
                next_info.append(info.get_name())

            self.assertEqual(iter_info, next_info)

        self.loop.run_until_complete(run())

    def test_async_cancellation(self):
        """Cancellation raises G_IO_ERROR_CANCELLED"""

        f = Gio.file_new_for_path("./")

        async def run():
            nonlocal self

            # cancellable created implicitly
            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
            res.cancel()
            with self.assertRaisesRegex(GLib.GError, "Operation was cancelled"):
                await res

            # cancellable passed explicitly
            cancel = Gio.Cancellable()
            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT, cancel)
            self.assertEqual(res.cancellable, cancel)
            cancel.cancel()
            with self.assertRaisesRegex(GLib.GError, "Operation was cancelled"):
                await res

        self.loop.run_until_complete(run())

    def test_not_completed(self):
        """Querying an uncompleted task raises exceptions"""

        f = Gio.file_new_for_path("./")

        async def run():
            nonlocal self

            # cancellable created implicitly
            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
            with self.assertRaises(asyncio.InvalidStateError):
                res.result()

            with self.assertRaises(asyncio.InvalidStateError):
                res.exception()

            # And, await it
            await res

        self.loop.run_until_complete(run())

    def test_async_cancel_completed(self):
        """Cancelling a completed task just cancels the cancellable"""

        f = Gio.file_new_for_path("./")

        async def run():
            nonlocal self

            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
            await res
            assert not res.cancellable.is_cancelled()
            res.cancel()
            assert res.cancellable.is_cancelled()

        self.loop.run_until_complete(run())

    def test_async_completed_add_cb(self):
        """Adding a done cb to a completed future queues it with call_soon"""

        f = Gio.file_new_for_path("./")

        called = False

        def cb():
            nonlocal called
            called = True

        async def run():
            nonlocal called, self

            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
            await res
            self.loop.call_soon(cb)

            # Python await is smart and does not iterate the EventLoop
            await res
            assert not called

            # So create a new future and wait on that
            fut = asyncio.Future()

            def done_cb(res):
                nonlocal fut
                fut.set_result(res.result())

            res.add_done_callback(done_cb)
            await fut
            assert called

        self.loop.run_until_complete(run())

    @pytest.mark.xfail(platform.python_implementation() == "PyPy", reason="Exception reporting does not work in pypy")
    def test_deleting_failed_logs(self):
        f = Gio.file_new_for_path("./")

        async def run():
            nonlocal self

            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
            res.cancel()
            # Cancellation in Gio is not immediate, so sleep for a bit
            await asyncio.sleep(0.5)

        exc = None
        msg = None

        def handler(loop, context):
            nonlocal exc, msg
            msg = context['message']
            exc = context['exception']

        self.loop.set_exception_handler(handler)
        self.loop.run_until_complete(run())

        self.assertRegex(msg, ".*exception was never retrieved")
        self.assertIsInstance(exc, GLib.GError)
        assert exc.matches(Gio.io_error_quark(), Gio.IOErrorEnum.CANCELLED)

    def test_no_running_loop(self):
        f = Gio.file_new_for_path("./")

        res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
        self.assertIsNone(res)

    def test_wrong_default_context(self):
        f = Gio.file_new_for_path("./")

        async def run():
            nonlocal self

            ctx = GLib.MainContext.new()
            GLib.MainContext.push_thread_default(ctx)
            self.addCleanup(GLib.MainContext.pop_thread_default, ctx)

            res = f.enumerate_children_async("standard::*", 0, GLib.PRIORITY_DEFAULT)
            self.assertIsNone(res)

        self.loop.run_until_complete(run())
