"""Pylons bootstrap environment.

Place 'pylons_config_file' into alembic.ini, and the application will
be loaded from there.

"""
from logging.config import fileConfig

from paste.deploy import loadapp

from alembic import context


try:
    # if pylons app already in, don't create a new app
    from pylons import config as pylons_config

    pylons_config["__file__"]
except:
    config = context.config
    # can use config['__file__'] here, i.e. the Pylons
    # ini file, instead of alembic.ini
    config_file = config.get_main_option("pylons_config_file")
    if config_file is not None:
        fileConfig(config_file)
    wsgi_app = loadapp("config:%s" % config_file, relative_to=".")


# customize this section for non-standard engine configurations.
meta = __import__(
    "%s.model.meta" % wsgi_app.config["pylons.package"]
).model.meta

# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
target_metadata = None


def run_migrations_offline():
    """Run migrations in 'offline' mode.

    This configures the context with just a URL
    and not an Engine, though an Engine is acceptable
    here as well.  By skipping the Engine creation
    we don't even need a DBAPI to be available.

    Calls to context.execute() here emit the given string to the
    script output.

    """
    context.configure(
        url=meta.engine.url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )
    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online():
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    """
    # specify here how the engine is acquired
    # engine = meta.engine
    raise NotImplementedError("Please specify engine connectivity here")

    with engine.connect() as connection:  # noqa
        context.configure(
            connection=connection, target_metadata=target_metadata
        )

        with context.begin_transaction():
            context.run_migrations()


if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()