"""
Database connection and session management.
Uses SQLAlchemy 2.0 async-compatible patterns.
"""
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, declarative_base
from app.config import get_settings

settings = get_settings()

# Create engine - using psycopg3 driver
# Convert postgresql:// to postgresql+psycopg:// for psycopg3
db_url = settings.database_url
if db_url.startswith("postgresql://"):
    db_url = db_url.replace("postgresql://", "postgresql+psycopg://", 1)

engine = create_engine(
    db_url,
    pool_pre_ping=True,  # Verify connections before using
    pool_size=5,
    max_overflow=10
)

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

# Base class for all models
Base = declarative_base()


def get_db():
    """
    Dependency that provides a database session.
    Ensures proper cleanup after request completes.
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()