"""SQLAlchemy async engine and declarative base for activity-core."""

import os

from sqlalchemy.ext.asyncio import AsyncEngine, create_async_engine
from sqlalchemy.orm import DeclarativeBase


class Base(DeclarativeBase):
    pass


def make_engine(url: str | None = None) -> AsyncEngine:
    """Return an async engine. Falls back to ACTCORE_DB_URL, then the dev default."""
    resolved = url or os.environ.get(
        "ACTCORE_DB_URL",
        "postgresql+asyncpg://actcore:actcore@localhost:5433/actcore",
    )
    return create_async_engine(resolved, echo=False)