from sqlalchemy.testing import fixtures
from sqlalchemy.sql.ddl import SchemaGenerator, SchemaDropper
from sqlalchemy.engine import default
from sqlalchemy import MetaData, Table, Column, Integer, Sequence
from sqlalchemy import schema
from sqlalchemy.testing.mock import Mock

class EmitDDLTest(fixtures.TestBase):
    def _mock_connection(self, item_exists):
        def has_item(connection, name, schema):
            return item_exists(name)

        return Mock(dialect=Mock(
                    supports_sequences=True,
                    has_table=Mock(side_effect=has_item),
                    has_sequence=Mock(side_effect=has_item)
                )
                )

    def _mock_create_fixture(self, checkfirst, tables,
                    item_exists=lambda item: False):
        connection = self._mock_connection(item_exists)

        return SchemaGenerator(connection.dialect, connection,
                    checkfirst=checkfirst,
                    tables=tables)

    def _mock_drop_fixture(self, checkfirst, tables,
                    item_exists=lambda item: True):
        connection = self._mock_connection(item_exists)

        return SchemaDropper(connection.dialect, connection,
                    checkfirst=checkfirst,
                    tables=tables)

    def _table_fixture(self):
        m = MetaData()

        return (m, ) + tuple(
                            Table('t%d' % i, m, Column('x', Integer))
                            for i in range(1, 6)
                        )

    def _table_seq_fixture(self):
        m = MetaData()

        s1 = Sequence('s1')
        s2 = Sequence('s2')
        t1 = Table('t1', m, Column("x", Integer, s1, primary_key=True))
        t2 = Table('t2', m, Column("x", Integer, s2, primary_key=True))

        return m, t1, t2, s1, s2


    def test_create_seq_checkfirst(self):
        m, t1, t2, s1, s2 = self._table_seq_fixture()
        generator = self._mock_create_fixture(True, [t1, t2],
                        item_exists=lambda t: t not in ("t1", "s1")
                        )

        self._assert_create([t1, s1], generator, m)


    def test_drop_seq_checkfirst(self):
        m, t1, t2, s1, s2 = self._table_seq_fixture()
        generator = self._mock_drop_fixture(True, [t1, t2],
                        item_exists=lambda t: t in ("t1", "s1")
                        )

        self._assert_drop([t1, s1], generator, m)

    def test_create_collection_checkfirst(self):
        m, t1, t2, t3, t4, t5 = self._table_fixture()
        generator = self._mock_create_fixture(True, [t2, t3, t4],
                        item_exists=lambda t: t not in ("t2", "t4")
                        )

        self._assert_create_tables([t2, t4], generator, m)

    def test_drop_collection_checkfirst(self):
        m, t1, t2, t3, t4, t5 = self._table_fixture()
        generator = self._mock_drop_fixture(True, [t2, t3, t4],
                        item_exists=lambda t: t in ("t2", "t4")
                        )

        self._assert_drop_tables([t2, t4], generator, m)

    def test_create_collection_nocheck(self):
        m, t1, t2, t3, t4, t5 = self._table_fixture()
        generator = self._mock_create_fixture(False, [t2, t3, t4],
                        item_exists=lambda t: t not in ("t2", "t4")
                        )

        self._assert_create_tables([t2, t3, t4], generator, m)

    def test_create_empty_collection(self):
        m, t1, t2, t3, t4, t5 = self._table_fixture()
        generator = self._mock_create_fixture(True, [],
                        item_exists=lambda t: t not in ("t2", "t4")
                        )

        self._assert_create_tables([], generator, m)

    def test_drop_empty_collection(self):
        m, t1, t2, t3, t4, t5 = self._table_fixture()
        generator = self._mock_drop_fixture(True, [],
                        item_exists=lambda t: t in ("t2", "t4")
                        )

        self._assert_drop_tables([], generator, m)

    def test_drop_collection_nocheck(self):
        m, t1, t2, t3, t4, t5 = self._table_fixture()
        generator = self._mock_drop_fixture(False, [t2, t3, t4],
                        item_exists=lambda t: t in ("t2", "t4")
                        )

        self._assert_drop_tables([t2, t3, t4], generator, m)

    def test_create_metadata_checkfirst(self):
        m, t1, t2, t3, t4, t5 = self._table_fixture()
        generator = self._mock_create_fixture(True, None,
                        item_exists=lambda t: t not in ("t2", "t4")
                        )

        self._assert_create_tables([t2, t4], generator, m)

    def test_drop_metadata_checkfirst(self):
        m, t1, t2, t3, t4, t5 = self._table_fixture()
        generator = self._mock_drop_fixture(True, None,
                        item_exists=lambda t: t in ("t2", "t4")
                        )

        self._assert_drop_tables([t2, t4], generator, m)

    def test_create_metadata_nocheck(self):
        m, t1, t2, t3, t4, t5 = self._table_fixture()
        generator = self._mock_create_fixture(False, None,
                        item_exists=lambda t: t not in ("t2", "t4")
                        )

        self._assert_create_tables([t1, t2, t3, t4, t5], generator, m)

    def test_drop_metadata_nocheck(self):
        m, t1, t2, t3, t4, t5 = self._table_fixture()
        generator = self._mock_drop_fixture(False, None,
                        item_exists=lambda t: t in ("t2", "t4")
                        )

        self._assert_drop_tables([t1, t2, t3, t4, t5], generator, m)

    def _assert_create_tables(self, elements, generator, argument):
        self._assert_ddl(schema.CreateTable, elements, generator, argument)

    def _assert_drop_tables(self, elements, generator, argument):
        self._assert_ddl(schema.DropTable, elements, generator, argument)

    def _assert_create(self, elements, generator, argument):
        self._assert_ddl(
                (schema.CreateTable, schema.CreateSequence),
                elements, generator, argument)

    def _assert_drop(self, elements, generator, argument):
        self._assert_ddl(
                (schema.DropTable, schema.DropSequence),
                elements, generator, argument)

    def _assert_ddl(self, ddl_cls, elements, generator, argument):
        generator.traverse_single(argument)
        for call_ in generator.connection.execute.mock_calls:
            c = call_[1][0]
            assert isinstance(c, ddl_cls)
            assert c.element in elements, "element %r was not expected"\
                             % c.element
            elements.remove(c.element)
        assert not elements, "elements remain in list: %r" % elements