from alembic import util

from . import exclusions

if util.sqla_094:
    from sqlalchemy.testing.requirements import Requirements
else:
    class Requirements(object):
        pass


class SuiteRequirements(Requirements):
    @property
    def schemas(self):
        """Target database must support external schemas, and have one
        named 'test_schema'."""

        return exclusions.open()

    @property
    def unique_constraint_reflection(self):
        def doesnt_have_check_uq_constraints(config):
            if not util.sqla_084:
                return True
            from sqlalchemy import inspect
            insp = inspect(config.db)
            try:
                insp.get_unique_constraints('x')
            except NotImplementedError:
                return True
            except TypeError:
                return True
            except Exception:
                pass
            return False

        return exclusions.skip_if(
            lambda config: not util.sqla_084,
            "SQLAlchemy 0.8.4 or greater required"
        ) + exclusions.skip_if(doesnt_have_check_uq_constraints)

    @property
    def foreign_key_match(self):
        return exclusions.fails_if(
            lambda config: not util.sqla_08,
            "MATCH for foreign keys added in SQLAlchemy 0.8.0"
        )

    @property
    def check_constraints_w_enforcement(self):
        """Target database must support check constraints
        and also enforce them."""

        return exclusions.open()

    @property
    def reflects_pk_names(self):
        return exclusions.closed()

    @property
    def reflects_fk_options(self):
        return exclusions.closed()

    @property
    def fail_before_sqla_079(self):
        return exclusions.fails_if(
            lambda config: not util.sqla_079,
            "SQLAlchemy 0.7.9 or greater required"
        )

    @property
    def fail_before_sqla_080(self):
        return exclusions.fails_if(
            lambda config: not util.sqla_08,
            "SQLAlchemy 0.8.0 or greater required"
        )

    @property
    def fail_before_sqla_083(self):
        return exclusions.fails_if(
            lambda config: not util.sqla_083,
            "SQLAlchemy 0.8.3 or greater required"
        )

    @property
    def fail_before_sqla_084(self):
        return exclusions.fails_if(
            lambda config: not util.sqla_084,
            "SQLAlchemy 0.8.4 or greater required"
        )

    @property
    def fail_before_sqla_09(self):
        return exclusions.fails_if(
            lambda config: not util.sqla_09,
            "SQLAlchemy 0.9.0 or greater required"
        )

    @property
    def fail_before_sqla_100(self):
        return exclusions.fails_if(
            lambda config: not util.sqla_100,
            "SQLAlchemy 1.0.0 or greater required"
        )

    @property
    def fail_before_sqla_099(self):
        return exclusions.fails_if(
            lambda config: not util.sqla_099,
            "SQLAlchemy 0.9.9 or greater required"
        )

    @property
    def fail_before_sqla_110(self):
        return exclusions.fails_if(
            lambda config: not util.sqla_110,
            "SQLAlchemy 1.1.0 or greater required"
        )

    @property
    def sqlalchemy_08(self):

        return exclusions.skip_if(
            lambda config: not util.sqla_08,
            "SQLAlchemy 0.8.0b2 or greater required"
        )

    @property
    def sqlalchemy_09(self):
        return exclusions.skip_if(
            lambda config: not util.sqla_09,
            "SQLAlchemy 0.9.0 or greater required"
        )

    @property
    def sqlalchemy_092(self):
        return exclusions.skip_if(
            lambda config: not util.sqla_092,
            "SQLAlchemy 0.9.2 or greater required"
        )

    @property
    def sqlalchemy_094(self):
        return exclusions.skip_if(
            lambda config: not util.sqla_094,
            "SQLAlchemy 0.9.4 or greater required"
        )

    @property
    def sqlalchemy_110(self):
        return exclusions.skip_if(
            lambda config: not util.sqla_110,
            "SQLAlchemy 1.1.0 or greater required"
        )