import sqlalchemy as sa
from sqlalchemy import Column
from sqlalchemy import Computed
from sqlalchemy import exc
from sqlalchemy import Identity
from sqlalchemy import Integer
from sqlalchemy import MetaData
from sqlalchemy import Table

from alembic import command
from alembic import op
from alembic.testing import assert_raises_message
from alembic.testing import combinations
from alembic.testing import eq_
from alembic.testing import is_true
from alembic.testing.env import _no_sql_testing_config
from alembic.testing.env import clear_staging_env
from alembic.testing.env import staging_env
from alembic.testing.env import three_rev_fixture
from alembic.testing.fixtures import capture_context_buffer
from alembic.testing.fixtures import op_fixture
from alembic.testing.fixtures import TestBase
from alembic.testing.suite._autogen_fixtures import AutogenFixtureTest
from alembic.util import sqla_compat


class FullEnvironmentTests(TestBase):
    @classmethod
    def setup_class(cls):
        staging_env()
        cls.cfg = cfg = _no_sql_testing_config("oracle")

        cls.a, cls.b, cls.c = three_rev_fixture(cfg)

    @classmethod
    def teardown_class(cls):
        clear_staging_env()

    def test_begin_commit(self):
        with capture_context_buffer(transactional_ddl=True) as buf:
            command.upgrade(self.cfg, self.a, sql=True)
        assert "SET TRANSACTION READ WRITE\n\n/" in buf.getvalue()
        assert "COMMIT\n\n/" in buf.getvalue()

    def test_batch_separator_default(self):
        with capture_context_buffer() as buf:
            command.upgrade(self.cfg, self.a, sql=True)
        assert "/" in buf.getvalue()
        assert ";" not in buf.getvalue()

    def test_batch_separator_custom(self):
        with capture_context_buffer(oracle_batch_separator="BYE") as buf:
            command.upgrade(self.cfg, self.a, sql=True)
        assert "BYE" in buf.getvalue()


class OpTest(TestBase):
    def test_add_column(self):
        context = op_fixture("oracle")
        op.add_column("t1", Column("c1", Integer, nullable=False))
        context.assert_("ALTER TABLE t1 ADD c1 INTEGER NOT NULL")

    def test_add_column_with_default(self):
        context = op_fixture("oracle")
        op.add_column(
            "t1", Column("c1", Integer, nullable=False, server_default="12")
        )
        context.assert_("ALTER TABLE t1 ADD c1 INTEGER DEFAULT '12' NOT NULL")

    def test_add_column_with_comment(self):
        context = op_fixture("oracle")
        op.add_column(
            "t1", Column("c1", Integer, nullable=False, comment="c1 comment")
        )
        context.assert_(
            "ALTER TABLE t1 ADD c1 INTEGER NOT NULL",
            "COMMENT ON COLUMN t1.c1 IS 'c1 comment'",
        )

    def test_add_column_computed(self):
        context = op_fixture("oracle")
        op.add_column(
            "t1",
            Column("some_column", Integer, Computed("foo * 5")),
        )
        context.assert_(
            "ALTER TABLE t1 ADD some_column "
            "INTEGER GENERATED ALWAYS AS (foo * 5)"
        )

    @combinations(
        (lambda: Computed("foo * 5"), lambda: None),
        (lambda: None, lambda: Computed("foo * 5")),
        (
            lambda: Computed("foo * 42"),
            lambda: Computed("foo * 5"),
        ),
    )
    def test_alter_column_computed_not_supported(self, sd, esd):
        op_fixture("oracle")
        assert_raises_message(
            exc.CompileError,
            'Adding or removing a "computed" construct, e.g. '
            "GENERATED ALWAYS AS, to or from an existing column is not "
            "supported.",
            op.alter_column,
            "t1",
            "c1",
            server_default=sd(),
            existing_server_default=esd(),
        )

    def test_alter_table_rename_oracle(self):
        context = op_fixture("oracle")
        op.rename_table("s", "t")
        context.assert_("ALTER TABLE s RENAME TO t")

    def test_alter_table_rename_schema_oracle(self):
        context = op_fixture("oracle")
        op.rename_table("s", "t", schema="myowner")
        context.assert_("ALTER TABLE myowner.s RENAME TO t")

    def test_alter_column_rename_oracle(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", new_column_name="x")
        context.assert_("ALTER TABLE t RENAME COLUMN c TO x")

    def test_alter_column_new_type(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", type_=Integer)
        context.assert_("ALTER TABLE t MODIFY c INTEGER")

    def test_alter_column_add_comment(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", type_=Integer, comment="c comment")
        context.assert_(
            "ALTER TABLE t MODIFY c INTEGER",
            "COMMENT ON COLUMN t.c IS 'c comment'",
        )

    def test_alter_column_add_comment_quotes(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", type_=Integer, comment="c 'comment'")
        context.assert_(
            "ALTER TABLE t MODIFY c INTEGER",
            "COMMENT ON COLUMN t.c IS 'c ''comment'''",
        )

    def test_alter_column_drop_comment(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", type_=Integer, comment=None)
        context.assert_(
            "ALTER TABLE t MODIFY c INTEGER", "COMMENT ON COLUMN t.c IS ''"
        )

    def test_create_table_comment(self):
        # this is handled by SQLAlchemy's compilers
        context = op_fixture("oracle")
        op.create_table_comment("t2", comment="t2 table", schema="foo")
        context.assert_("COMMENT ON TABLE foo.t2 IS 't2 table'")

    def test_drop_table_comment(self):
        # this is handled by SQLAlchemy's compilers
        context = op_fixture("oracle")
        op.drop_table_comment("t2", existing_comment="t2 table", schema="foo")
        context.assert_("COMMENT ON TABLE foo.t2 IS ''")

    def test_drop_index(self):
        context = op_fixture("oracle")
        op.drop_index("my_idx", table_name="my_table")
        context.assert_contains("DROP INDEX my_idx")

    def test_drop_column_w_default(self):
        context = op_fixture("oracle")
        op.drop_column("t1", "c1")
        context.assert_("ALTER TABLE t1 DROP COLUMN c1")

    def test_drop_column_w_check(self):
        context = op_fixture("oracle")
        op.drop_column("t1", "c1")
        context.assert_("ALTER TABLE t1 DROP COLUMN c1")

    def test_alter_column_nullable_w_existing_type(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", nullable=True, existing_type=Integer)
        context.assert_("ALTER TABLE t MODIFY c NULL")

    def test_alter_column_not_nullable_w_existing_type(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", nullable=False, existing_type=Integer)
        context.assert_("ALTER TABLE t MODIFY c NOT NULL")

    def test_alter_column_nullable_w_new_type(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", nullable=True, type_=Integer)
        context.assert_(
            "ALTER TABLE t MODIFY c NULL", "ALTER TABLE t MODIFY c INTEGER"
        )

    def test_alter_column_not_nullable_w_new_type(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", nullable=False, type_=Integer)
        context.assert_(
            "ALTER TABLE t MODIFY c NOT NULL", "ALTER TABLE t MODIFY c INTEGER"
        )

    def test_alter_add_server_default(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", server_default="5")
        context.assert_("ALTER TABLE t MODIFY c DEFAULT '5'")

    def test_alter_replace_server_default(self):
        context = op_fixture("oracle")
        op.alter_column(
            "t", "c", server_default="5", existing_server_default="6"
        )
        context.assert_("ALTER TABLE t MODIFY c DEFAULT '5'")

    def test_alter_remove_server_default(self):
        context = op_fixture("oracle")
        op.alter_column("t", "c", server_default=None)
        context.assert_("ALTER TABLE t MODIFY c DEFAULT NULL")

    def test_alter_do_everything(self):
        context = op_fixture("oracle")
        op.alter_column(
            "t",
            "c",
            new_column_name="c2",
            nullable=True,
            type_=Integer,
            server_default="5",
        )
        context.assert_(
            "ALTER TABLE t MODIFY c NULL",
            "ALTER TABLE t MODIFY c DEFAULT '5'",
            "ALTER TABLE t MODIFY c INTEGER",
            "ALTER TABLE t RENAME COLUMN c TO c2",
        )

    def test_create_table_with_column_comments(self):
        context = op_fixture("oracle")
        op.create_table(
            "t2", Column("c1", Integer, primary_key=True), comment="t2 comment"
        )
        context.assert_(
            "CREATE TABLE t2 (c1 INTEGER NOT NULL, PRIMARY KEY (c1))",
            "COMMENT ON TABLE t2 IS 't2 comment'",
        )

    # TODO: when we add schema support
    # def test_alter_column_rename_oracle_schema(self):
    #    context = op_fixture('oracle')
    #    op.alter_column("t", "c", name="x", schema="y")
    #    context.assert_(
    #        'ALTER TABLE y.t RENAME COLUMN c TO c2'
    #    )


class IdentityTest(AutogenFixtureTest, TestBase):
    __requires__ = ("identity_columns",)
    __backend__ = True
    __only_on__ = "oracle"

    def _identity_qualification(self, kw):
        always = kw.get("always", False)
        if always is None:
            return ""
        qualification = "ALWAYS" if always else "BY DEFAULT"
        if kw.get("oracle_on_null", False):
            qualification += " ON NULL"
        return qualification

    def _adapt_identity_kw(self, data):
        res = data.copy()
        if not sqla_compat.identity_has_dialect_kwargs:
            for k in data:
                if k.startswith("oracle_"):
                    res[k[7:]] = res.pop(k)
        return res

    @combinations(
        ({}, None),
        (dict(always=True), None),
        (dict(always=None, oracle_order=True), "ORDER"),
        (
            dict(start=3, increment=33, maxvalue=99, cycle=True),
            "INCREMENT BY 33 START WITH 3 MAXVALUE 99 CYCLE",
        ),
        (dict(oracle_on_null=True, start=42), "START WITH 42"),
    )
    def test_add_column_identity(self, kw, text):
        context = op_fixture("oracle")
        op.add_column(
            "t1",
            Column(
                "some_column",
                Integer,
                Identity(**self._adapt_identity_kw(kw)),
            ),
        )
        qualification = self._identity_qualification(kw)
        options = " (%s)" % text if text else ""
        context.assert_(
            "ALTER TABLE t1 ADD some_column "
            "INTEGER GENERATED %s AS IDENTITY%s" % (qualification, options)
        )

    @combinations(
        ({}, None),
        (dict(always=True), None),
        (dict(always=None, cycle=True), "CYCLE"),
        (
            dict(start=3, increment=33, maxvalue=99, cycle=True),
            "INCREMENT BY 33 START WITH 3 MAXVALUE 99 CYCLE",
        ),
        (dict(oracle_on_null=True, start=42), "START WITH 42"),
    )
    def test_add_identity_to_column(self, kw, text):
        context = op_fixture("oracle")
        op.alter_column(
            "t1",
            "some_column",
            server_default=Identity(**self._adapt_identity_kw(kw)),
            existing_server_default=None,
        )
        qualification = self._identity_qualification(kw)
        options = " (%s)" % text if text else ""
        context.assert_(
            "ALTER TABLE t1 MODIFY some_column "
            "GENERATED %s AS IDENTITY%s" % (qualification, options)
        )

    def test_remove_identity_from_column(self):
        context = op_fixture("oracle")
        op.alter_column(
            "t1",
            "some_column",
            server_default=None,
            existing_server_default=Identity(),
        )
        context.assert_("ALTER TABLE t1 MODIFY some_column DROP IDENTITY")

    @combinations(
        ({}, dict(always=True), None),
        (
            dict(always=True),
            dict(always=False, start=3),
            "START WITH 3",
        ),
        (
            dict(always=True, start=3, increment=2, minvalue=-3, maxvalue=99),
            dict(
                always=True,
                start=3,
                increment=1,
                minvalue=-3,
                maxvalue=99,
                cycle=True,
            ),
            "INCREMENT BY 1 START WITH 3 MINVALUE -3 MAXVALUE 99 CYCLE",
        ),
        (
            dict(
                always=False,
                start=3,
                maxvalue=9999,
                minvalue=0,
            ),
            dict(
                always=False,
                start=3,
                oracle_order=True,
                oracle_on_null=False,
                cache=2,
            ),
            "START WITH 3 CACHE 2 ORDER",
        ),
        (
            dict(always=False),
            dict(always=None, minvalue=0),
            "MINVALUE 0",
        ),
    )
    def test_change_identity_in_column(self, existing, updated, text):
        context = op_fixture("oracle")
        op.alter_column(
            "t1",
            "some_column",
            server_default=Identity(**self._adapt_identity_kw(updated)),
            existing_server_default=Identity(
                **self._adapt_identity_kw(existing)
            ),
        )

        qualification = self._identity_qualification(updated)
        options = " (%s)" % text if text else ""
        context.assert_(
            "ALTER TABLE t1 MODIFY some_column "
            "GENERATED %s AS IDENTITY%s" % (qualification, options)
        )

    def test_identity_on_null(self):
        m1 = MetaData()
        m2 = MetaData()

        Table(
            "user",
            m1,
            Column(
                "id",
                Integer,
                Identity(
                    **self._adapt_identity_kw(
                        dict(start=2, oracle_on_null=True)
                    )
                ),
            ),
            Column("other", sa.Text),
        )

        Table(
            "user",
            m2,
            Column(
                "id",
                Integer,
                Identity(
                    **self._adapt_identity_kw(
                        dict(start=2, oracle_on_null=False)
                    )
                ),
            ),
            Column("other", sa.Text),
        )

        diffs = self._fixture(m1, m2)
        eq_(len(diffs[0]), 1)
        diffs = diffs[0][0]
        eq_(diffs[0], "modify_default")
        eq_(diffs[2], "user")
        eq_(diffs[3], "id")
        old = diffs[5]
        new = diffs[6]

        is_true(isinstance(old, sa.Identity))
        is_true(isinstance(new, sa.Identity))