"""Database configuration 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 app.config import settings


# Create database engine
engine = create_engine(
    settings.database_url,
    connect_args={"check_same_thread": False} if "sqlite" in settings.database_url else {},
    echo=settings.debug
)

# 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 function to get database session.
    
    Yields:
        Session: SQLAlchemy database session
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


def init_db() -> None:
    """Initialize database tables."""
    Base.metadata.create_all(bind=engine)