"""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

try:
    from app.config import settings
except ModuleNotFoundError:
    from backend.app.config import settings

# Create database engine
engine = create_engine(
    settings.database_url,
    pool_pre_ping=True,
    pool_size=10,
    max_overflow=20,
)

# 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 to get database session.

    Yields:
        Database session
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


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