import struct

import unittest

from mercurial.node import hex

try:

    from mercurial import rustext

    rustext.__name__  # trigger immediate actual import

except ImportError:

    rustext = None

else:

    from mercurial.rustext import revlog

    # this would fail already without appropriate ancestor.__package__

    from mercurial.rustext.ancestor import LazyAncestors

from mercurial.testing import revlog as revlogtesting

header = struct.unpack(">I", revlogtesting.data_non_inlined[:4])[0]

@unittest.skipIf(

    rustext is None,

    "rustext module revlog relies on is not available",

)

class RustRevlogIndexTest(revlogtesting.RevlogBasedTestBase):

    def test_heads(self):

        idx = self.parseindex()

        rustidx = revlog.Index(revlogtesting.data_non_inlined, header)

        self.assertEqual(rustidx.headrevs(), idx.headrevs())

    def test_len(self):

        idx = self.parseindex()

        rustidx = revlog.Index(revlogtesting.data_non_inlined, header)

        self.assertEqual(len(rustidx), len(idx))

    def test_ancestors(self):

        rustidx = revlog.Index(revlogtesting.data_non_inlined, header)

        lazy = LazyAncestors(rustidx, [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.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])

        # let's check bool for an empty one

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

@unittest.skipIf(

    rustext is None,

    "rustext module revlog relies on is not available",

)

class RustRevlogNodeTreeClassTest(revlogtesting.RustRevlogBasedTestBase):

    def test_standalone_nodetree(self):

        idx = self.parserustindex()

        nt = revlog.NodeTree(idx)

        for i in range(4):

            nt.insert(i)

        bin_nodes = [entry[7] for entry in idx]

        hex_nodes = [hex(n) for n in bin_nodes]

        for i, node in enumerate(hex_nodes):

            self.assertEqual(nt.prefix_rev_lookup(node), i)

            self.assertEqual(nt.prefix_rev_lookup(node[:5]), i)

        # all 4 revisions in idx (standard data set) have different

        # first nybbles in their Node IDs,

        # hence `nt.shortest()` should return 1 for them, except when

        # the leading nybble is 0 (ambiguity with NULL_NODE)

        for i, (bin_node, hex_node) in enumerate(zip(bin_nodes, hex_nodes)):

            shortest = nt.shortest(bin_node)

            expected = 2 if hex_node[0] == ord('0') else 1

            self.assertEqual(shortest, expected)

            self.assertEqual(nt.prefix_rev_lookup(hex_node[:shortest]), i)

        # test invalidation (generation poisoning) detection

        del idx[3]

        self.assertTrue(nt.is_invalidated())

if __name__ == '__main__':

    import silenttestrunner

    silenttestrunner.main(__name__)