"""
Database configuration module.

This module provides database session management.
Configuration is now centralized in app.config.Settings.
"""
import os
from typing import Generator

from sqlalchemy import create_engine
from sqlalchemy.orm import Session, sessionmaker

from app.config import get_settings


def get_engine():
    """Create SQLAlchemy engine from settings."""
    settings = get_settings()
    return create_engine(
        settings.DATABASE_URL,
        pool_size=settings.DATABASE_POOL_SIZE,
        max_overflow=settings.DATABASE_MAX_OVERFLOW,
        pool_timeout=settings.DATABASE_POOL_TIMEOUT,
        pool_recycle=settings.DATABASE_POOL_RECYCLE,
    )


# Create engine and session factory
_engine = get_engine()
_SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=_engine)


def get_db_session() -> Generator[Session, None, None]:
    """Get database session with automatic cleanup.
    
    Yields:
        Session: SQLAlchemy session
    """
    session: Session = _SessionLocal()
    try:
        yield session
    finally:
        session.close()