"""SQLAlchemy engine and session construction for the Hub database only."""

from __future__ import annotations

from collections.abc import Callable
from datetime import UTC, datetime
from typing import Any

from sqlalchemy import Engine, create_engine, event
from sqlalchemy.orm import DeclarativeBase, Session, sessionmaker


class Base(DeclarativeBase):
    """Declarative root for Hub-owned tables; ContextForge is never imported."""


def utc_now() -> datetime:
    return datetime.now(UTC)


def create_engine_from_url(database_url: str, **kwargs: Any) -> Engine:
    """Create an engine with safe SQLite test defaults and explicit pool settings."""

    options: dict[str, Any] = {"future": True, "pool_pre_ping": True, **kwargs}
    if database_url.startswith("sqlite"):
        options.setdefault("connect_args", {"check_same_thread": False})
    engine = create_engine(database_url, **options)
    if database_url.startswith("sqlite"):

        def enable_sqlite_foreign_keys(dbapi_connection: Any, _: Any) -> None:
            dbapi_connection.execute("PRAGMA foreign_keys=ON")

        event.listen(engine, "connect", enable_sqlite_foreign_keys)
    return engine


def session_factory(engine: Engine) -> Callable[[], Session]:
    """Return an explicit session factory; no hidden global session is used."""

    return sessionmaker(bind=engine, autoflush=False, expire_on_commit=False, class_=Session)