import unittest

from igraph import Graph, InternalError, Matching


def powerset(iterable):
    items_powers = [(item, 1 << i) for i, item in enumerate(iterable)]
    for i in range(1 << len(items_powers)):
        for item, power in items_powers:
            if i & power:
                yield item


leda_graph = Graph(
    [
        (0, 8),
        (0, 12),
        (0, 14),
        (1, 9),
        (1, 10),
        (1, 13),
        (2, 8),
        (2, 9),
        (3, 10),
        (3, 11),
        (3, 13),
        (4, 9),
        (4, 14),
        (5, 14),
        (6, 9),
        (6, 14),
        (7, 8),
        (7, 12),
        (7, 14),
    ]
)
leda_graph.vs["type"] = [0] * 8 + [1] * 7


class MatchingTests(unittest.TestCase):
    def setUp(self):
        self.matching = Matching(
            leda_graph, [12, 10, 8, 13, -1, 14, 9, -1, 2, 6, 1, -1, 0, 3, 5], "type"
        )

    def testIsMaximal(self):
        self.assertTrue(self.matching.is_maximal())
        self.matching.matching[0] = -1
        self.matching.matching[12] = -1
        self.assertFalse(self.matching.is_maximal())

    def testMatchingRetrieval(self):
        m = [12, 10, 8, 13, -1, 14, 9, -1, 2, 6, 1, -1, 0, 3, 5]
        self.assertEqual(self.matching.matching, m)
        for i, mate in enumerate(m):
            if mate == -1:
                self.assertFalse(self.matching.is_matched(i))
                self.assertEqual(self.matching.match_of(i), None)
            else:
                self.assertTrue(self.matching.is_matched(i))
                self.assertEqual(self.matching.match_of(i), mate)
                self.assertEqual(
                    self.matching.match_of(leda_graph.vs[i]).index,
                    leda_graph.vs[mate].index,
                )


class MaximumBipartiteMatchingTests(unittest.TestCase):
    def testBipartiteMatchingSimple(self):
        # Specifying the "type" attribute explicitly
        matching = leda_graph.maximum_bipartite_matching("type")
        self.assertEqual(len(matching), 6)
        self.assertTrue(matching.is_maximal())

        # Using the default attribute
        matching = leda_graph.maximum_bipartite_matching()
        self.assertEqual(len(matching), 6)
        self.assertTrue(matching.is_maximal())

    def testBipartiteMatchingErrors(self):
        # Type vector too short
        g = Graph([(0, 1), (1, 2), (2, 3)])
        self.assertRaises(InternalError, g.maximum_bipartite_matching, types=[0, 1, 0])

        # Graph not bipartite
        self.assertRaises(
            InternalError, g.maximum_bipartite_matching, types=[0, 1, 1, 1]
        )


def suite():
    matching_suite = unittest.defaultTestLoader.loadTestsFromTestCase(MatchingTests)
    bipartite_unweighted_suite = unittest.defaultTestLoader.loadTestsFromTestCase(MaximumBipartiteMatchingTests)
    return unittest.TestSuite([matching_suite, bipartite_unweighted_suite])


def test():
    runner = unittest.TextTestRunner()
    runner.run(suite())


if __name__ == "__main__":
    test()
