"""
Database engine and session — SQLModel/SQLAlchemy, no Django.

Reads DATABASE_URL from the environment.
"""

from __future__ import annotations

import os

from sqlalchemy import create_engine
from sqlmodel import Session

DATABASE_URL = os.environ.get("DATABASE_URL", "postgresql://mpr:mpr@localhost:5432/mpr")

_engine = None


def get_engine():
    global _engine
    if _engine is None:
        _engine = create_engine(DATABASE_URL, pool_size=5, max_overflow=10)
    return _engine


def get_session() -> Session:
    return Session(get_engine())


def create_tables():
    """Create all SQLModel tables."""
    from sqlmodel import SQLModel
    from . import tables  # noqa — registers all table classes
    SQLModel.metadata.create_all(get_engine())