from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import Session
import logging
import os
from contextlib import contextmanager


# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# Database configuration
DATABASE_URL = os.getenv("DATABASE_URL", "sqlite:///database.db")

engine = create_engine(DATABASE_URL)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()

def get_db():
    """Dependency to get a database session. Used for simple, single service operations."""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

@contextmanager
def transaction(db: Session):
    """Context manager to handle database transactions. Used for service operations that require multiple database operations."""
    try:
        yield
        db.commit()
    except Exception as e:
        db.rollback()
        raise e

def init_db():
    Base.metadata.create_all(bind=engine)