import sys

import unittest

from mercurial.node import wdirrev

from mercurial.testing import revlog as revlogtesting

try:

    from mercurial import rustext

    rustext.__name__  # trigger immediate actual import

except ImportError:

    rustext = None

else:

    # this would fail already without appropriate ancestor.__package__

    from mercurial.rustext.ancestor import (

        AncestorsIterator,

        LazyAncestors,

        MissingAncestors,

    )

    from mercurial.rustext import dagop

try:

    from mercurial.cext import parsers as cparsers

except ImportError:

    cparsers = None

@unittest.skipIf(

    rustext is None,

    'The Rust version of the "ancestor" module is not available. It is needed'

    ' for this test.',

)

@unittest.skipIf(

    rustext is None,

    'The Rust or C version of the "parsers" module, which the "ancestor" module'

    ' relies on, is not available.',

)

class rustancestorstest(revlogtesting.RevlogBasedTestBase):

    """Test the correctness of binding to Rust code.

    This test is merely for the binding to Rust itself: extraction of

    Python variable, giving back the results etc.

    It is not meant to test the algorithmic correctness of the operations

    on ancestors it provides. Hence the very simple embedded index data is

    good enough.

    Algorithmic correctness is asserted by the Rust unit tests.

    """

    def testiteratorrevlist(self):

        idx = self.parseindex()

        # checking test assumption about the index binary data:

        self.assertEqual(

            {i: (r[5], r[6]) for i, r in enumerate(idx)},

            {0: (-1, -1), 1: (0, -1), 2: (1, -1), 3: (2, -1)},

        )

        ait = AncestorsIterator(idx, [3], 0, True)

        self.assertEqual([r for r in ait], [3, 2, 1, 0])

        ait = AncestorsIterator(idx, [3], 0, False)

        self.assertEqual([r for r in ait], [2, 1, 0])

    def testlazyancestors(self):

        idx = self.parseindex()

        start_count = sys.getrefcount(idx)  # should be 2 (see Python doc)

        self.assertEqual(

            {i: (r[5], r[6]) for i, r in enumerate(idx)},

            {0: (-1, -1), 1: (0, -1), 2: (1, -1), 3: (2, -1)},

        )

        lazy = LazyAncestors(idx, [3], 0, True)

        # we have two more references to the index:

        # - in its inner iterator for __contains__ and __bool__

        # - in the LazyAncestors instance itself (to spawn new iterators)

        self.assertEqual(sys.getrefcount(idx), start_count + 2)

        self.assertTrue(2 in lazy)

        self.assertTrue(bool(lazy))

        self.assertEqual(list(lazy), [3, 2, 1, 0])

        # a second time to validate that we spawn new iterators

        self.assertEqual(list(lazy), [3, 2, 1, 0])

        # now let's watch the refcounts closer

        ait = iter(lazy)

        self.assertEqual(sys.getrefcount(idx), start_count + 3)

        del ait

        self.assertEqual(sys.getrefcount(idx), start_count + 2)

        del lazy

        self.assertEqual(sys.getrefcount(idx), start_count)

        # let's check bool for an empty one

        self.assertFalse(LazyAncestors(idx, [0], 0, False))

    def testmissingancestors(self):

        idx = self.parseindex()

        missanc = MissingAncestors(idx, [1])

        self.assertTrue(missanc.hasbases())

        self.assertEqual(missanc.missingancestors([3]), [2, 3])

        missanc.addbases({2})

        self.assertEqual(missanc.bases(), {1, 2})

        self.assertEqual(missanc.missingancestors([3]), [3])

        self.assertEqual(missanc.basesheads(), {2})

    def testmissingancestorsremove(self):

        idx = self.parseindex()

        missanc = MissingAncestors(idx, [1])

        revs = {0, 1, 2, 3}

        missanc.removeancestorsfrom(revs)

        self.assertEqual(revs, {2, 3})

    def testrefcount(self):

        idx = self.parseindex()

        start_count = sys.getrefcount(idx)

        # refcount increases upon iterator init...

        ait = AncestorsIterator(idx, [3], 0, True)

        self.assertEqual(sys.getrefcount(idx), start_count + 1)

        self.assertEqual(next(ait), 3)

        # and decreases once the iterator is removed

        del ait

        self.assertEqual(sys.getrefcount(idx), start_count)

        # and removing ref to the index after iterator init is no issue

        ait = AncestorsIterator(idx, [3], 0, True)

        del idx

        self.assertEqual(list(ait), [3, 2, 1, 0])

    def testgrapherror(self):

        data = (

            revlogtesting.data_non_inlined[: 64 + 27]

            + b'\xf2'

            + revlogtesting.data_non_inlined[64 + 28 :]

        )

        idx = cparsers.parse_index2(data, False)[0]

        with self.assertRaises(rustext.GraphError) as arc:

            AncestorsIterator(idx, [1], -1, False)

        exc = arc.exception

        self.assertIsInstance(exc, ValueError)

        # rust-cpython issues appropriate str instances for Python 2 and 3

        self.assertEqual(exc.args, ('ParentOutOfRange', 1))

    def testwdirunsupported(self):

        # trying to access ancestors of the working directory raises

        idx = self.parseindex()

            list(AncestorsIterator(idx, [wdirrev], -1, False))

    def testheadrevs(self):

        idx = self.parseindex()

        self.assertEqual(dagop.headrevs(idx, [1, 2, 3]), {3})

if __name__ == '__main__':

    import silenttestrunner

    silenttestrunner.main(__name__)