"""Alembic environment configuration."""

import os
from logging.config import fileConfig

from alembic import context
from sqlalchemy import create_engine, pool

config = context.config

if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# Override sqlalchemy.url from environment variable
db_url = os.environ.get("DATABASE_URL", "")
if db_url:
    config.set_main_option("sqlalchemy.url", db_url)


def run_migrations_offline() -> None:
    """Run migrations in 'offline' mode."""
    url = config.get_main_option("sqlalchemy.url")
    context.configure(url=url, target_metadata=None, literal_binds=True, dialect_opts={"paramstyle": "named"})
    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    """Run migrations in 'online' mode."""
    connectable = create_engine(config.get_main_option("sqlalchemy.url"), poolclass=pool.NullPool)
    with connectable.connect() as connection:
        context.configure(connection=connection, target_metadata=None)
        with context.begin_transaction():
            context.run_migrations()


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