"""
Database connection and session management using SQLAlchemy.
"""
from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
from .config import settings

# Create database engine
engine = create_engine(
    settings.DATABASE_URL,
    pool_pre_ping=True,  # Verify connections before using
    echo=settings.DEBUG  # Log SQL queries in debug mode
)

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

# Base class for models
Base = declarative_base()


def get_db():
    """
    Dependency function to get database session.
    Yields a session and ensures it's closed after use.
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()