database.py

import os
from dotenv import load_dotenv
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, declarative_base
from typing import Generator

# Load environment variables
load_dotenv()
SQLALCHEMY_DATABASE_URL = os.getenv("DATABASE_URL")

# --- Connection Configuration ---
# Note for Neon: pool_recycle helps with "scale to zero" to prevent idle connections
# from being dropped by the server. 280 seconds is less than Neon's 5-minute timeout.
engine = create_engine(
    SQLALCHEMY_DATABASE_URL, 
    pool_pre_ping=True, 
    pool_recycle=280
)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

# Base class for our models
Base = declarative_base()

# --- Dependency Function for Database Session ---
def get_db() -> Generator:
    """Provides a transactional session to the database."""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()