backend/app/database.py

"""
SQLAlchemy database setup with SQLite.
Uses synchronous SQLAlchemy for simplicity and compatibility.
"""
import os
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, declarative_base
from app.config import get_settings

settings = get_settings()

# ── Ensure data directory exists ─────────────────────
db_path = settings.DATABASE_URL.replace("sqlite:///", "")
os.makedirs(os.path.dirname(db_path) if os.path.dirname(db_path) else ".", exist_ok=True)

# ── Engine & Session ─────────────────────────────────
engine = create_engine(
    settings.DATABASE_URL,
    connect_args={"check_same_thread": False},  # Required for SQLite
    echo=settings.DEBUG,
)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

Base = declarative_base()


def get_db():
    """FastAPI dependency — yields a DB session per request."""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db():
    """Create all tables on startup."""
    from app import models  # noqa: F401 — import to register models
    Base.metadata.create_all(bind=engine)