"""Database connection and session management."""
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, Session
from typing import Generator

from ..utils.config import settings

# Create SQLAlchemy engine
engine = create_engine(
    settings.DATABASE_URL,
    pool_pre_ping=True,  # Enable connection health checks
    echo=settings.DEBUG,  # Log SQL queries in debug mode
)

# Create session factory
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

# Base class for models
Base = declarative_base()


def get_db() -> Generator[Session, None, None]:
    """Dependency for getting database session.

    Yields:
        Database session

    Usage:
        @app.get("/")
        def endpoint(db: Session = Depends(get_db)):
            ...
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db() -> None:
    """Initialize database (create tables).

    Note:
        In production, use Alembic migrations instead.
    """
    Base.metadata.create_all(bind=engine)