"""
Alembic env.py — punto de entrada de las migraciones.

Lee la URL de conexión de MIGRATION_DATABASE_URL (recomendado: user con DDL
separado), o de DATABASE_URL como fallback.
"""

from logging.config import fileConfig

from sqlalchemy import engine_from_config, pool

from alembic import context
from app.settings import settings

config = context.config

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

config.set_main_option("sqlalchemy.url", settings.migration_url)

# Importar Base y modelos para que --autogenerate los detecte:
#   from app.models import Base
#   target_metadata = Base.metadata
target_metadata = None


def run_migrations_offline() -> None:
    """Genera SQL sin conectar — útil para revisar antes de aplicar."""
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )
    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    """Aplica migraciones contra la BD real."""
    connectable = engine_from_config(
        config.get_section(config.config_ini_section, {}),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )
    with connectable.connect() as connection:
        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()