"""
migrations_tenant/env.py
------------------------
Standalone Alembic environment for running the EXISTING tenant migration chain
(migrations/versions) against an ARBITRARY tenant database.

Unlike migrations/env.py — which is Flask-Migrate-coupled and always targets
the app's default database via current_app — this reads sqlalchemy.url straight
from the Alembic config supplied per-tenant by control/tenant_migrate.py, and
reuses the same version scripts through version_locations. No Flask import, so
it can run for any tenant DB outside an app context.

The normal `flask db ...` workflow is unaffected; it still uses migrations/env.py.
"""

from logging.config import fileConfig

from sqlalchemy import create_engine, pool
from alembic import context

config = context.config

# Only configure logging if an ini file was supplied (the runner builds the
# Config programmatically, so this is typically skipped).
if config.config_file_name is not None:
    try:
        fileConfig(config.config_file_name)
    except Exception:
        pass

# Raw-SQL migrations with INFORMATION_SCHEMA guards — autogenerate is not used,
# so no target metadata is required here.
target_metadata = None


def run_migrations_offline():
    context.configure(
        url=config.get_main_option('sqlalchemy.url'),
        target_metadata=target_metadata,
        literal_binds=True,
        compare_type=False,
    )
    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online():
    url = config.get_main_option('sqlalchemy.url')
    connectable = create_engine(url, poolclass=pool.NullPool, future=True)
    try:
        with connectable.connect() as connection:
            context.configure(connection=connection, target_metadata=target_metadata)
            with context.begin_transaction():
                context.run_migrations()
    finally:
        connectable.dispose()


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